nvmem: core: Print error on wrong bits DT property

The algorithms in nvmem core are built with the constraint that
bit_offset < 8. If bit_offset is greater the results are wrong. Print an
error if the devicetree 'bits' property is outside of the valid range
and abort parsing.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20240224114516.86365-12-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: include bit index in cell sysfs file name

Creating sysfs files for all Cells caused a boot failure for linux-6.8-rc1 on
Apple M1, which (in downstream dts files) has multiple nvmem cells that use the
same byte address. This causes the device probe to fail with

[ 0.605336] sysfs: cannot create duplicate filename '/devices/platform/soc@200000000/2922bc000.efuse/apple_efuses_nvmem0/cells/efuse@a10'
[ 0.605347] CPU: 7 PID: 1 Comm: swapper/0 Tainted: G S 6.8.0-rc1-arnd-5+ #133
[ 0.605355] Hardware name: Apple Mac Studio (M1 Ultra, 2022) (DT)
[ 0.605362] Call trace:
[ 0.605365] show_stack+0x18/0x2c
[ 0.605374] dump_stack_lvl+0x60/0x80
[ 0.605383] dump_stack+0x18/0x24
[ 0.605388] sysfs_warn_dup+0x64/0x80
[ 0.605395] sysfs_add_bin_file_mode_ns+0xb0/0xd4
[ 0.605402] internal_create_group+0x268/0x404
[ 0.605409] sysfs_create_groups+0x38/0x94
[ 0.605415] devm_device_add_groups+0x50/0x94
[ 0.605572] nvmem_populate_sysfs_cells+0x180/0x1b0
[ 0.605682] nvmem_register+0x38c/0x470
[ 0.605789] devm_nvmem_register+0x1c/0x6c
[ 0.605895] apple_efuses_probe+0xe4/0x120
[ 0.606000] platform_probe+0xa8/0xd0

As far as I can tell, this is a problem for any device with multiple cells on
different bits of the same address. Avoid the issue by changing the file name
to include the first bit number.

Fixes: 0331c611949f ("nvmem: core: Expose cells through sysfs")
Link: https://github.com/AsahiLinux/linux/blob/bd0a1a7d4/arch/arm64/boot/dts/apple/t600x-dieX.dtsi#L156
Cc: <regressions@lists.linux.dev>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Rafał Miłecki <rafal@milecki.pl>
Cc: Chen-Yu Tsai <wenst@chromium.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <asahi@lists.linux.dev>
Cc: Sven Peter <sven@svenpeter.dev>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Eric Curtin <ecurtin@redhat.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20240209163454.98051-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add nvmem_dev_size() helper

This is required by layouts that need to read whole NVMEM content. It's
especially useful for NVMEM devices without hardcoded layout (like
U-Boot environment data block).

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20231221173421.13737-2-zajec5@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: drop nvmem_layout_get_match_data()

Thanks for layouts refactoring we now have "struct device" associated
with layout. Also its OF pointer points directly to the "nvmem-layout"
DT node.

All it takes to get match data is a generic of_device_get_match_data().

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20231219120104.3422-2-zajec5@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: layouts: refactor .add_cells() callback arguments

Simply pass whole "struct nvmem_layout" instead of single variables.
There is nothing in "struct nvmem_layout" that we have to hide from
layout drivers. They also access it during .probe() and .remove().

Thanks to this change:

1. API gets more consistent
All layouts drivers callbacks get the same argument

2. Layouts get correct device
Before this change NVMEM core code was passing NVMEM device instead
of layout device. That resulted in:
* Confusing prints
* Calling devm_*() helpers on wrong device
* Helpers like of_device_get_match_data() dereferencing NULLs

3. It gets possible to get match data
First of all nvmem_layout_get_match_data() requires passing "struct
nvmem_layout" which .add_cells() callback didn't have before this. It
doesn't matter much as it's rather useless now anyway (and will be
dropped).
What's more important however is that of_device_get_match_data() can
be used now thanks to owning a proper device pointer.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20231219120104.3422-1-zajec5@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Expose cells through sysfs

The binary content of nvmem devices is available to the user so in the
easiest cases, finding the content of a cell is rather easy as it is
just a matter of looking at a known and fixed offset. However, nvmem
layouts have been recently introduced to cope with more advanced
situations, where the offset and size of the cells is not known in
advance or is dynamic. When using layouts, more advanced parsers are
used by the kernel in order to give direct access to the content of each
cell, regardless of its position/size in the underlying
device. Unfortunately, these information are not accessible by users,
unless by fully re-implementing the parser logic in userland.

Let's expose the cells and their content through sysfs to avoid these
situations. Of course the relevant NVMEM sysfs Kconfig option must be
enabled for this support to be available.

Not all nvmem devices expose cells. Indeed, the .bin_attrs attribute
group member will be filled at runtime only when relevant and will
remain empty otherwise. In this case, as the cells attribute group will
be empty, it will not lead to any additional folder/file creation.

Exposed cells are read-only. There is, in practice, everything in the
core to support a write path, but as I don't see any need for that, I
prefer to keep the interface simple (and probably safer). The interface
is documented as being in the "testing" state which means we can later
add a write attribute if though relevant.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Rafał Miłecki <rafal@milecki.pl>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231215111536.316972-9-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Rework layouts to become regular devices

Current layout support was initially written without modules support in
mind. When the requirement for module support rose, the existing base
was improved to adopt modularization support, but kind of a design flaw
was introduced. With the existing implementation, when a storage device
registers into NVMEM, the core tries to hook a layout (if any) and
populates its cells immediately. This means, if the hardware description
expects a layout to be hooked up, but no driver was provided for that,
the storage medium will fail to probe and try later from
scratch. Even if we consider that the hardware description shall be
correct, we could still probe the storage device (especially if it
contains the rootfs).

One way to overcome this situation is to consider the layouts as
devices, and leverage the native notifier mechanism. When a new NVMEM
device is registered, we can populate its nvmem-layout child, if any,
and wait for the matching to be done in order to get the cells (the
waiting can be easily done with the NVMEM notifiers). If the layout
driver is compiled as a module, it should automatically be loaded. This
way, there is no strong order to enforce, any NVMEM device creation
or NVMEM layout driver insertion will be observed as a new event which
may lead to the creation of additional cells, without disturbing the
probes with costly (and sometimes endless) deferrals.

In order to achieve that goal we create a new bus for the nvmem-layouts
with minimal logic to match nvmem-layout devices with nvmem-layout
drivers. All this infrastructure code is created in the layouts.c file.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231215111536.316972-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Move and rename ->fixup_cell_info()

This hook is meant to be used by any provider and instantiating a layout
just for this is useless. Let's instead move this hook to the nvmem
device and add it to the config structure to be easily shared by the
providers.

While at moving this hook, rename it ->fixup_dt_cell_info() to clarify
its main intended purpose.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231215111536.316972-6-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Simplify the ->add_cells() hook

The layout entry is not used and will anyway be made useless by the new
layout bus infrastructure coming next, so drop it. While at it, clarify
the kdoc entry.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231215111536.316972-5-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Create a header for internal sharing

Before adding all the NVMEM layout bus infrastructure to the core, let's
move the main nvmem_device structure in an internal header, only
available to the core. This way all the additional code can be added in
a dedicated file in order to keep the current core file tidy.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231215111536.316972-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Move of_nvmem_layout_get_container() in another header

nvmem-consumer.h is included by consumer devices, extracting data from
NVMEM devices whereas nvmem-provider.h is included by devices providing
NVMEM content.

The only users of of_nvmem_layout_get_container() outside of the core
are layout drivers, so better move its prototype to nvmem-provider.h.

While we do so, we also move the kdoc associated with the function to
the header rather than the .c file.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231215111536.316972-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Do not expect fixed layouts to grab a layout driver

Two series lived in parallel for some time, which led to this situation:
- The nvmem-layout container is used for dynamic layouts
- We now expect fixed layouts to also use the nvmem-layout container but
this does not require any additional driver, the support is built-in the
nvmem core.

Ensure we don't refuse to probe for wrong reasons.

Fixes: 27f699e578b1 ("nvmem: core: add support for fixed cells *layout*")
Cc: stable@vger.kernel.org
Reported-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Rafał Miłecki <rafal@milecki.pl>
Tested-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com>

Link: https://lore.kernel.org/r/20231124193814.360552-1-miquel.raynal@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Revert "nvmem: add new config option"

This reverts commit 517f14d9cf3533d5ab4fded195ab6f80a92e378f.

Config option "no_of_node" is no longer needed since adding a more
explicit and targeted option "add_legacy_fixed_of_cells".

That "no_of_node" config option was needed *earlier* to help mtd's case.

DT nodes of MTD partitions (that are also NVMEM devices) may contain
subnodes. Those SHOULD NOT be treated as NVMEM fixed cells.

To prevent NVMEM core code from parsing subnodes a "no_of_node" option
was added (and set to true in mtd) to make for_each_child_of_node() in
NVMEM a no-op. That was a bit hacky because it was messing with
"of_node" pointer to achieve some side-effect.

With the introduction of "add_legacy_fixed_of_cells" config option
things got more explicit. MTD subsystem simply tells NVMEM when to look
for fixed cells and there is no need to hack "of_node" pointer anymore.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231023102759.31529-1-zajec5@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: add explicit config option to read old syntax fixed OF cells

Binding for fixed NVMEM cells defined directly as NVMEM device subnodes
has been deprecated. It has been replaced by the "fixed-layout" NVMEM
layout binding.

New syntax is meant to be clearer and should help avoiding imprecise
bindings.

NVMEM subsystem already supports the new binding. It should be a good
idea to limit support for old syntax to existing drivers that actually
support & use it (we can't break backward compatibility!). That way we
additionally encourage new bindings & drivers to ignore deprecated
binding.

It wasn't clear (to me) if rtc and w1 code actually uses old syntax
fixed cells. I enabled them to don't risk any breakage.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
[for meson-{efuse,mx-efuse}.c]
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
[for mtk-efuse.c, nvmem/core.c, nvmem-provider.h]
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
[MT8192, MT8195 Chromebooks]
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
[for microchip-otpc.c]
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
[SAMA7G5-EK]
Tested-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20231020105545.216052-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Notify when a new layout is registered

Tell listeners a new layout was introduced and is now available.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230823132744.350618-23-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Do not open-code existing functions

Use of_nvmem_layout_get_container() instead of hardcoding it.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230823132744.350618-22-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Create all cells before adding the nvmem device

Let's pack all the cells creation in one place, so they are all created
before we add the nvmem device.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230823132744.350618-20-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230823132744.350618-14-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add support for fixed cells *layout*

This adds support for the "fixed-layout" NVMEM layout binding. It allows
defining NVMEM cells in a layout DT node named "nvmem-layout".

While NVMEM subsystem supports layout drivers it has been discussed that
"fixed-layout" may actually be supperted internally. It's because:
1. It's a very basic layout
2. It allows sharing code with legacy syntax parsing
3. It's safer for soc_device_match() due to -EPROBE_DEFER
4. This will make the syntax transition easier

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Message-ID: <20230611140330.154222-26-srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: remove MODULE_LICENSE in non-modules

Since commit 8b41fc4454e ("kbuild: create modules.builtin without
Makefile.modbuiltin or tristate.conf"), MODULE_LICENSE declarations
are used to identify modules. As a consequence, uses of the macro
in non-modules will cause modprobe to misidentify their containing
object file as a module when it is not (false positives), and modprobe
might succeed rather than failing with a suitable error message.

So remove it in the files in this commit, none of which can be built as
modules.

Signed-off-by: Nick Alcock <nick.alcock@oracle.com>
Suggested-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-modules@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Hitomi Hasegawa <hasegawa-hitomi@fujitsu.com>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

nvmem: core: support specifying both: cell raw data & post read lengths

Callback .read_post_process() is designed to modify raw cell content
before providing it to the consumer. So far we were dealing with
modifications that didn't affect cell size (length). In some cases
however cell content needs to be reformatted and resized.

It's required e.g. to provide properly formatted MAC address in case
it's stored in a non-binary format (e.g. using ASCII).

There were few discussions how to optimally handle that. Following
possible solutions were considered:
1. Allow .read_post_process() to realloc (resize) content buffer
2. Allow .read_post_process() to adjust (decrease) just buffer length
3. Register NVMEM cells using post-read sizes

The preferred solution was the last one. The problem is that simply
adjusting "bytes" in NVMEM providers would result in core code NOT
passing whole raw data to .read_post_process() callbacks. It means
callback functions couldn't do their job without somehow manually
reading original cell content on their own.

This patch deals with that by registering NVMEM cells with both lengths:
raw content one and post read one. It allows:
1. Core code to read whole raw cell content
2. Callbacks to return content they want

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-35-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: provide own priv pointer in post process callback

It doesn't make any more sense to have a opaque pointer set up by the
nvmem device. Usually, the layout isn't associated with a particular
nvmem device. Instead, let the caller who set the post process callback
provide the priv pointer.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-21-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: cell: drop global cell_post_process

There are no users anymore for the global cell_post_process callback
anymore. New users should use proper nvmem layouts.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-20-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: allow to modify a cell before adding it

Provide a way to modify a cell before it will get added. This is useful
to attach a custom post processing hook via a layout.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-18-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add per-cell post processing

Instead of relying on the name the consumer is using for the cell, like
it is done for the nvmem .cell_post_process configuration parameter,
provide a per-cell post processing hook. This can then be populated by
the NVMEM provider (or the NVMEM layout) when adding the cell.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-17-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: request layout modules loading

When a storage device like an eeprom or an mtd device probes, it
registers an nvmem device if the nvmem subsystem has been enabled (bool
symbol). During nvmem registration, if the device is using layouts to
expose dynamic nvmem cells, the core will first try to get a reference
over the layout driver callbacks. In practice there is not relationship
that can be described between the storage driver and the nvmem
layout. So there is no way we can enforce both drivers will be built-in
or both will be modules. If the storage device driver is built-in but
the layout is built as a module, instead of badly failing with an
endless probe deferral loop, lets just make a modprobe call in case the
driver was made available in an initramfs with
of_device_node_request_module(), and offer a fully functional system to
the user.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-16-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: handle the absence of expected layouts

Make nvmem_layout_get() return -EPROBE_DEFER while the expected layout
is not available. This condition cannot be triggered today as nvmem
layout drivers are initialed as part of an early init call, but soon
these drivers will be converted into modules and be initialized with a
standard priority, so the unavailability of the drivers might become a
reality that must be taken care of.

Let's anticipate this by telling the caller the layout might not yet be
available. A probe deferral is requested in this case.

Please note this does not affect any nvmem device not using layouts,
because an early check against the "nvmem-layout" container presence
will return NULL in this case.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-15-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: introduce NVMEM layouts

NVMEM layouts are used to generate NVMEM cells during runtime. Think of
an EEPROM with a well-defined conent. For now, the content can be
described by a device tree or a board file. But this only works if the
offsets and lengths are static and don't change. One could also argue
that putting the layout of the EEPROM in the device tree is the wrong
place. Instead, the device tree should just have a specific compatible
string.

Right now there are two use cases:
(1) The NVMEM cell needs special processing. E.g. if it only specifies
a base MAC address offset and you need to add an offset, or it
needs to parse a MAC from ASCII format or some proprietary format.
(Post processing of cells is added in a later commit).
(2) u-boot environment parsing. The cells don't have a particular
offset but it needs parsing the content to determine the offsets
and length.

Co-developed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230404172148.82422-14-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: return -ENOENT if nvmem cell is not found

Prior to commit 5d8e6e6c10a3 ("nvmem: core: add an index parameter to
the cell") of_nvmem_cell_get() would return -ENOENT if the cell wasn't
found. Particularly, if of_property_match_string() returned -EINVAL,
that return code was passed as the index to of_parse_phandle(), which
then detected it as invalid and returned NULL. That led to an return
code of -ENOENT.

With the new code, the negative index will lead to an -EINVAL of
of_parse_phandle_with_optional_args() which pass straight to the
caller and break those who expect an -ENOENT.

Fix it by always returning -ENOENT.

Fixes: 5d8e6e6c10a3 ("nvmem: core: add an index parameter to the cell")
Reported-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/2143916.GUh0CODmnK@steina-w/
Signed-off-by: Michael Walle <michael@walle.cc>
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230310094845.139400-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: use nvmem_add_one_cell() in nvmem_add_cells_from_of()

Convert nvmem_add_cells_from_of() to use the new nvmem_add_one_cell().
This will remove duplicate code and it will make it possible to add a
hook to a nvmem layout in between, which can change fields before the
cell is finally added.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230206134356.839737-17-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add nvmem_add_one_cell()

Add a new function to add exactly one cell. This will be used by the
nvmem layout drivers to add custom cells. In contrast to the
nvmem_add_cells(), this has the advantage that we don't have to assemble
a list of cells on runtime.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230206134356.839737-16-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: drop the removal of the cells in nvmem_add_cells()

If nvmem_add_cells() fails, the whole nvmem_register() will fail
and the cells will then be removed anyway. This is a preparation
to introduce a nvmem_add_one_cell() which can then be used by
nvmem_add_cells().

This is then the same to what nvmem_add_cells_from_table() and
nvmem_add_cells_from_of() do.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230206134356.839737-15-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add an index parameter to the cell

Sometimes a cell can represend multiple values. For example, a base
ethernet address stored in the NVMEM can be expanded into multiple
discreet ones by adding an offset.

For this use case, introduce an index parameter which is then used to
distiguish between values. This parameter will then be passed to the
post process hook which can then use it to create different values
during reading.

At the moment, there is only support for the device tree path. You can
add the index to the phandle, e.g.

&net {
nvmem-cells = <&base_mac_address 2>;
nvmem-cell-names = "mac-address";
};

&nvmem_provider {
base_mac_address: base-mac-address@0 {
#nvmem-cell-cells = <1>;
reg = <0 6>;
};
};

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230206134356.839737-13-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: remove spurious white space

Remove a spurious white space in for the ida_alloc() call.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230206134356.839737-8-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix return value

Dan Carpenter points out that the return code was not set in commit
60c8b4aebd8e ("nvmem: core: fix cleanup after dev_set_name()"), but
this is not the only issue - we also need to zero wp_gpio to prevent
gpiod_put() being called on an error value.

Fixes: 560181d3ace6 ("nvmem: core: fix cleanup after dev_set_name()")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230127104015.23839-10-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix cell removal on error

nvmem_add_cells() could return an error after some cells are already
added to the provider. In this case, the added cells are not removed.
Remove any registered cells if nvmem_add_cells() fails.

Fixes: fa72d847d68d7 ("nvmem: check the return value of nvmem_add_cells()")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230127104015.23839-9-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix device node refcounting

In of_nvmem_cell_get(), of_get_next_parent() is used on cell_np. This
will decrement the refcount on cell_np, but cell_np is still used later
in the code. Use of_get_parent() instead and of_node_put() in the
appropriate places.

Fixes: 69aba7948cbe ("nvmem: Add a simple NVMEM framework for consumers")
Fixes: 7ae6478b304b ("nvmem: core: rework nvmem cell instance creation")
Cc: stable@vger.kernel.org
Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230127104015.23839-8-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix registration vs use race

The i.MX6 CPU frequency driver sometimes fails to register at boot time
due to nvmem_cell_read_u32() sporadically returning -ENOENT.

This happens because there is a window where __nvmem_device_get() in
of_nvmem_cell_get() is able to return the nvmem device, but as cells
have been setup, nvmem_find_cell_entry_by_node() returns NULL.

The occurs because the nvmem core registration code violates one of the
fundamental principles of kernel programming: do not publish data
structures before their setup is complete.

Fix this by making nvmem core code conform with this principle.

Fixes: eace75cfdcf7 ("nvmem: Add a simple NVMEM framework for nvmem providers")
Cc: stable@vger.kernel.org
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230127104015.23839-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix cleanup after dev_set_name()

If dev_set_name() fails, we leak nvmem->wp_gpio as the cleanup does not
put this. While a minimal fix for this would be to add the gpiod_put()
call, we can do better if we split device_register(), and use the
tested nvmem_release() cleanup code by initialising the device early,
and putting the device.

This results in a slightly larger fix, but results in clear code.

Note: this patch depends on "nvmem: core: initialise nvmem->id early"
and "nvmem: core: remove nvmem_config wp_gpio".

Fixes: 5544e90c8126 ("nvmem: core: add error handling for dev_set_name")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
[Srini: Fixed subject line and error code handing with wp_gpio while applying.]
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230127104015.23839-6-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: remove nvmem_config wp_gpio

No one provides wp_gpio, so let's remove it to avoid issues with
the nvmem core putting this gpio.

Cc: stable@vger.kernel.org
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230127104015.23839-5-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: initialise nvmem->id early

The error path for wp_gpio attempts to free the IDA nvmem->id, but
this has yet to be assigned, so will always be zero - leaking the
ID allocated by ida_alloc(). Fix this by moving the initialisation
of nvmem->id earlier.

Fixes: f7d8d7dcd978 ("nvmem: fix memory leak in error path")
Cc: stable@vger.kernel.org
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20230127104015.23839-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add error handling for dev_set_name

The type of return value of dev_set_name is int, which may return
wrong result, so we add error handling for it to reclaim memory
of nvmem resource, and return early when an error occurs.

Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220916122100.170016-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Fix memleak in nvmem_register()

dev_set_name will alloc memory for nvmem->dev.kobj.name in
nvmem_register, when nvmem_validate_keepouts failed, nvmem's
memory will be freed and return, but nobody will free memory
for nvmem->dev.kobj.name, there will be memleak, so moving
nvmem_validate_keepouts() after device_register() and let
the device core deal with cleaning name in error cases.

Fixes: de0534df9347 ("nvmem: core: fix error handling while validating keepout regions")
Cc: stable@vger.kernel.org
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220916120402.38753-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: support passing DT node in cell info

Some hardware may have NVMEM cells described in Device Tree using
individual nodes. Let drivers pass such nodes to the NVMEM subsystem so
they can be later used by NVMEM consumers.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220429162701.2222-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Check input parameter for NULL in nvmem_unregister()

nvmem_unregister() frees resources and standard pattern is to allow
caller to not care if it's NULL or not. This will reduce burden on
the callers to perform this check.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220220151527.17216-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Use devm_add_action_or_reset()

Slightly simplify the devm_nvmem_register() by using the
devm_add_action_or_reset().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220220151527.17216-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Remove unused devm_nvmem_unregister()

There are no users and seems no will come of the devm_nvmem_unregister().
Remove the function and remove the unused devm_nvmem_match() along with it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220220151527.17216-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Fix a conflict between MTD and NVMEM on wp-gpios property

Wp-gpios property can be used on NVMEM nodes and the same property can
be also used on MTD NAND nodes. In case of the wp-gpios property is
defined at NAND level node, the GPIO management is done at NAND driver
level. Write protect is disabled when the driver is probed or resumed
and is enabled when the driver is released or suspended.

When no partitions are defined in the NAND DT node, then the NAND DT node
will be passed to NVMEM framework. If wp-gpios property is defined in
this node, the GPIO resource is taken twice and the NAND controller
driver fails to probe.

It would be possible to set config->wp_gpio at MTD level before calling
nvmem_register function but NVMEM framework will toggle this GPIO on
each write when this GPIO should only be controlled at NAND level driver
to ensure that the Write Protect has not been enabled.

A way to fix this conflict is to add a new boolean flag in nvmem_config
named ignore_wp. In case ignore_wp is set, the GPIO resource will
be managed by the provider.

Fixes: 2a127da461a9 ("nvmem: add support for the write-protect pin")
Cc: stable@vger.kernel.org
Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220220151432.16605-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: set size for sysfs bin file

For some reason we never set the size for nvmem sysfs binary file.
Set this.

Reported-by: Gilles BULOZ <gilles.buloz@kontron.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20211130133909.6154-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add nvmem cell post processing callback

Some NVMEM providers have certain nvmem cells encoded, which requires
post processing before actually using it.

For example mac-address is stored in either in ascii or delimited or reverse-order.

Having a post-process callback hook to provider drivers would enable them to
do this vendor specific post processing before nvmem consumers see it.

Tested-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20211013131957.30271-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: rework nvmem cell instance creation

In the existing design, we do not create a instance per nvmem cell consumer
but we directly refer cell from nvmem cell list that are added to provider.

However this design has some limitations when consumers want to assign name
or connection id the nvmem cell instance, ex: via "nvmem-cell-names" or
id in nvmem_cell_get(id).

Having a name associated with nvmem cell consumer instance will help
provider drivers in performing post processing of nvmem cell data if required
before data is seen by the consumers. This is pretty normal with some vendors
storing nvmem cells like mac-address in a vendor specific data layouts that
are not directly usable by the consumer drivers.

With this patch nvmem cell will be created dynamically during nvmem_cell_get
and destroyed in nvmem_cell_put, allowing consumers to associate name with
nvmem cell consumer instance.

With this patch a new struct nvmem_cell_entry replaces struct nvmem_cell
for storing nvmem cell information within the core.
This patch does not change nvmem-consumer interface based on nvmem_cell.

Tested-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20211013131957.30271-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Fix shift-out-of-bound (UBSAN) with byte size cells

If a cell has 'nbits' equal to a multiple of BITS_PER_BYTE the logic

*p &= GENMASK((cell->nbits%BITS_PER_BYTE) - 1, 0);

will become undefined behavior because nbits modulo BITS_PER_BYTE is 0, and we
subtract one from that making a large number that is then shifted more than the
number of bits that fit into an unsigned long.

UBSAN reports this problem:

UBSAN: shift-out-of-bounds in drivers/nvmem/core.c:1386:8
shift exponent 64 is too large for 64-bit type 'unsigned long'
CPU: 6 PID: 7 Comm: kworker/u16:0 Not tainted 5.15.0-rc3+ #9
Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
Workqueue: events_unbound deferred_probe_work_func
Call trace:
dump_backtrace+0x0/0x170
show_stack+0x24/0x30
dump_stack_lvl+0x64/0x7c
dump_stack+0x18/0x38
ubsan_epilogue+0x10/0x54
__ubsan_handle_shift_out_of_bounds+0x180/0x194
__nvmem_cell_read+0x1ec/0x21c
nvmem_cell_read+0x58/0x94
nvmem_cell_read_variable_common+0x4c/0xb0
nvmem_cell_read_variable_le_u32+0x40/0x100
a6xx_gpu_init+0x170/0x2f4
adreno_bind+0x174/0x284
component_bind_all+0xf0/0x264
msm_drm_bind+0x1d8/0x7a0
try_to_bring_up_master+0x164/0x1ac
__component_add+0xbc/0x13c
component_add+0x20/0x2c
dp_display_probe+0x340/0x384
platform_probe+0xc0/0x100
really_probe+0x110/0x304
__driver_probe_device+0xb8/0x120
driver_probe_device+0x4c/0xfc
__device_attach_driver+0xb0/0x128
bus_for_each_drv+0x90/0xdc
__device_attach+0xc8/0x174
device_initial_probe+0x20/0x2c
bus_probe_device+0x40/0xa4
deferred_probe_work_func+0x7c/0xb8
process_one_work+0x128/0x21c
process_scheduled_works+0x40/0x54
worker_thread+0x1ec/0x2a8
kthread+0x138/0x158
ret_from_fork+0x10/0x20

Fix it by making sure there are any bits to mask out.

Fixes: 69aba7948cbe ("nvmem: Add a simple NVMEM framework for consumers")
Cc: Douglas Anderson <dianders@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20211013124511.18726-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix error handling while validating keepout regions

Current error path on failure of validating keepout regions is calling
put_device, eventhough the device is not even registered at that point.

Fix this by adding proper error handling of freeing ida and nvmem.

Fixes: fd3bb8f54a88 ("nvmem: core: Add support for keepout regions")
Cc: <stable@vger.kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210806085947.22682-5-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add a missing of_node_put

'for_each_child_of_node' performs an of_node_get on each iteration, so a
return from the middle of the loop requires an of_node_put.

Fixes: e888d445ac33 ("nvmem: resolve cells from DT at registration time")
Cc: <stable@vger.kernel.org>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210611102321.11509-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: prepare basics for FRAM support

Added enum and string for FRAM (ferroelectric RAM) to expose it as file
named "fram".
Added documentation of sysfs file.

Signed-off-by: Jiri Prchal <jiri.prchal@aksignal.cz>
Link: https://lore.kernel.org/r/20210611094601.95131-2-jiri.prchal@aksignal.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: constify nvmem_cell_read_variable_common() return value

The caller doesn't modify the memory pointed to by the pointer so it
can be const.

Suggested-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210611083348.20170-9-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: allow specifying of_node

Until now, the of_node of the parent device is used. Some devices
provide more than just the nvmem provider. To avoid name space clashes,
add a way to allow specifying the nvmem cells in subnodes. Consider the
following example:

flash@0 {
compatible = "jedec,spi-nor";

partitions {
compatible = "fixed-partitions";
#address-cells = <1>;
#size-cells = <1>;

partition@0 {
reg = <0x000000 0x010000>;
};
};

otp {
compatible = "user-otp";
#address-cells = <1>;
#size-cells = <1>;

serial-number@0 {
reg = <0x0 0x8>;
};
};
};

There the nvmem provider might be the MTD partition or the OTP region of
the flash.

Add a new config->of_node parameter, which if set, will be used instead
of the parent's of_node.

Signed-off-by: Michael Walle <michael@walle.cc>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210424110608.15748-2-michael@walle.cc

nvmem: core: Fix unintentional sign extension issue

The shifting of the u8 integer buf[3] by 24 bits to the left will
be promoted to a 32 bit signed int and then sign-extended to a
u64. In the event that the top bit of buf[3] is set then all
then all the upper 32 bits of the u64 end up as also being set
because of the sign-extension. Fix this by casting buf[i] to
a u64 before the shift.

Fixes: a28e824fb827 ("nvmem: core: Add functions to make number reading easy")
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Addresses-Coverity: ("Unintended sign extension")
Link: https://lore.kernel.org/r/20210330111241.19401-8-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Add functions to make number reading easy

Sometimes the clients of nvmem just want to get a number out of
nvmem. They don't want to think about exactly how many bytes the nvmem
cell took up. They just want the number. Let's make it easy.

In general this concept is useful because nvmem space is precious and
usually the fewest bits are allocated that will hold a given value on
a given system. However, even though small numbers might be fine on
one system that doesn't mean that logically the number couldn't be
bigger. Imagine nvmem containing a max frequency for a component. On
one system perhaps that fits in 16 bits. On another system it might
fit in 32 bits. The code reading this number doesn't care--it just
wants the number.

We'll provide two functions: nvmem_cell_read_variable_le_u32() and
nvmem_cell_read_variable_le_u64().

Comparing these to the existing functions like nvmem_cell_read_u32():
* These new functions have no problems if the value was stored in
nvmem in fewer bytes. It's OK to use these function as long as the
value stored will fit in 32-bits (or 64-bits).
* These functions avoid problems that the earlier APIs had with bit
offsets. For instance, you can't use nvmem_cell_read_u32() to read a
value has nbits=32 and bit_offset=4 because the nvmem cell must be
at least 5 bytes big to hold this value. The new API accounts for
this and works fine.
* These functions make it very explicit that they assume that the
number was stored in little endian format. The old functions made
this assumption whenever bit_offset was non-zero (see
nvmem_shift_read_buffer_in_place()) but didn't whenever the
bit_offset was zero.

NOTE: it's assumed that we don't need an 8-bit or 16-bit version of
this function. The 32-bit version of the function can be used to read
8-bit or 16-bit data.

At the moment, I'm only adding the "unsigned" versions of these
functions, but if it ends up being useful someone could add a "signed"
version that did 2's complement sign extension.

At the moment, I'm only adding the "little endian" versions of these
functions. Adding the "big endian" version would require adding "big
endian" support to nvmem_shift_read_buffer_in_place().

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210330111241.19401-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: skip child nodes not matching binding

The nvmem cell binding applies to all eeprom child nodes matching
"^.*@[0-9a-f]+$" without taking a compatible into account.

Linux drivers, like at24, are even more extensive and assume
_all_ at24 eeprom child nodes to be nvmem cells since e888d445ac33
("nvmem: resolve cells from DT at registration time").

Since df5f3b6f5357 ("dt-bindings: nvmem: stm32: new property for
data access"), the additionalProperties: True means it's Ok to have
other properties as long as they don't match "^.*@[0-9a-f]+$".

The barebox bootloader extends the MTD partitions binding to
EEPROM and can fix up following device tree node:

&eeprom {
partitions {
compatible = "fixed-partitions";
};
};

This is allowed binding-wise, but drivers using nvmem_register()
like at24 will fail to parse because the function expects all child
nodes to have a reg property present. This results in the whole
EEPROM driver probe failing despite the device tree being correct.

Fix this by skipping nodes lacking a reg property instead of
returning an error. This effectively makes the drivers adhere
to the binding because all nodes with a unit address must have
a reg property and vice versa.

Fixes: e888d445ac33 ("nvmem: resolve cells from DT at registration time").
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210129171430.11328-6-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Fix a resource leak on error in nvmem_add_cells_from_of()

This doesn't call of_node_put() on the error path so it leads to a
memory leak.

Fixes: 0749aa25af82 ("nvmem: core: fix regression in of_nvmem_cell_get()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210129171430.11328-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Add support for keepout regions

Introduce support into the nvmem core for arrays of register ranges
that should not result in actual device access. For these regions a
constant byte (repeated) is returned instead on read, and writes are
quietly ignored and returned as successful.

This is useful for instance if certain efuse regions are protected
from access by Linux because they contain secret info to another part
of the system (like an integrated modem).

Signed-off-by: Evan Green <evgreen@chromium.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20201127102837.19366-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix possibly memleak when use nvmem_cell_info_to_nvmem_cell()

Fix missing 'kfree_const(cell->name)' when call to
nvmem_cell_info_to_nvmem_cell() in several places:

* after nvmem_cell_info_to_nvmem_cell() failed during
nvmem_add_cells()

* during nvmem_device_cell_{read,write} when cell->name is
kstrdup'ed() without calling kfree_const() at the end, but
really there is no reason to do that 'dup, because the cell
instance is allocated on the stack for some short period to be
read/write without exposing it to the caller.

So the new nvmem_cell_info_to_nvmem_cell_nodup() helper is introduced
which is used to convert cell_info -> cell without name duplication as
a lighweight version of nvmem_cell_info_to_nvmem_cell().

Fixes: e2a5402ec7c6 ("nvmem: Add nvmem_device based consumer apis.")
Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Vadym Kochan <vadym.kochan@plvision.eu>
Link: https://lore.kernel.org/r/20200923204456.14032-1-vadym.kochan@plvision.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix missing of_node_put() in of_nvmem_device_get()

of_parse_phandle() returns device_node with incremented ref count
which needs to be decremented by of_node_put() when device_node
is not used.

Fixes: e2a5402ec7c6 ("nvmem: Add nvmem_device based consumer apis.")
Signed-off-by: Vadym Kochan <vadym.kochan@plvision.eu>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200917134437.16637-5-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: switch to simpler IDA interface

We don't need to specify any ranges when allocating IDs so we can switch
to ida_alloc() and ida_free() instead of the ida_simple_ counterparts.

ida_simple_get(ida, 0, 0, gfp) is equivalent to
ida_alloc_range(ida, 0, UINT_MAX, gfp) which is equivalent to
ida_alloc(ida, gfp). Note: IDR will never actually allocate an ID
larger than INT_MAX.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200917134437.16637-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Use kobj_to_dev() instead of container_of()

Use kobj_to_dev() instead of container_of()

Signed-off-by: Tian Tao <tiantao6@hisilicon.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200917134437.16637-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add support to auto devid

For nvmem providers which have multiple instances, it is required
to suffix the provider name with proper id, so that they do not
confict for the same name. Currently the core does not handle
this case properly eventhough core already has logic to generate the id.

This patch add new devid type NVMEM_DEVID_AUTO for providers to be
able to allow core to assign id and append it to provier name.

Reported-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Link: https://lore.kernel.org/r/20200722100705.7772-8-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Add nvmem_cell_read_u8()

Complement the u16, u32 and u64 helpers with a u8 variant to ease
accessing byte-sized values.

This helper will be useful for Realtek Digital Home Center platforms,
which store some byte and sub-byte sized values in non-volatile memory.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200722100705.7772-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Grammar fixes for help text

It's "an unsigned" but "a U".
Similarly, "an entry" but "a binary entry".

While at it, also drop superfluous articles for negative and zero.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200722100705.7772-6-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Enforce nvmem stride in the sysfs interface

The 'struct nvmem_config' has a stride attribute that specifies the
needed alignment for accesses into the nvmem. This is used in
nvmem_cell_info_to_nvmem_cell() but not in the sysfs read/write
functions. If the alignment is important in one place it's important
everywhere, so let's add enforcement.

For now we'll consider it totally invalid to access with the wrong
alignment. We could relax this in the read case where we could just
read some extra bytes and throw them away. Relaxing it in the write
case seems harder (and less safe?) since we'd have to read some data
first and then write it back. To keep it symmetric we'll just
disallow it in both cases.

Reported-by: Ravi Kumar Bokka <rbokka@codeaurora.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Ravi Kumar Bokka <rbokka@codeaurora.org>
Tested-by: Ravi Kumar Bokka <rbokka@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200722100705.7772-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: ensure sysfs writes handle write-protect pin

Commit 2a127da461a9 ("nvmem: add support for the write-protect pin")
added support for handling write-protect pins to the nvmem core, and
Commit 1c89074bf850 ("eeprom: at24: remove the write-protect pin support")
retrofitted the at24 driver to use this support.

These changes broke write() on the nvmem sysfs attribute for eeproms
which utilize a write-protect pin, as the write callback invokes the
nvmem device's reg_write callback directly which no longer handles
changing the state of the write-protect pin.

Change the read and write callbacks for the sysfs attribute to invoke
nvmme_reg_read/nvmem_reg_write helpers which handle this, rather than
calling reg_read/reg_write directly.

Fixes: 2a127da461a9 ("nvmem: add support for the write-protect pin")
Signed-off-by: Michael Auchter <michael.auchter@ni.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200511145042.31223-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: cleanup old eeprom compat entry attributes

file permission are derived based on various configs for
default nvmem sysfs file, reuse it to create the eeprom
compat file too.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200417121306.23121-1-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: remove nvmem_sysfs_get_groups()

Now that we are using is_bin_visible callback, we do not need
nvmem_sysfs_get_groups() anymore so move all the relevant data-structures
and code to core.c

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200325131951.31887-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: use is_bin_visible for permissions

By using is_bin_visible callback to set permissions will remove a
large list of attribute groups. These group permissions can be
dynamically derived in the callback.

Also add checks for read/write callbacks and set permissions accordingly.

Suggested-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200325131951.31887-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: use device_register and device_unregister

use device_register/unregister instead of spliting them with no use.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200324171600.15606-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add root_only member to nvmem device struct

As we are planning to move to use sysfs is_bin_visible callback,
having root_only as part of nvmem_device will help decide correct
permissions.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200325122116.15096-2-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: validate nvmem config before parsing

nvmem provider has to provide either reg_read/write, add a check
to enforce this.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200310132257.23358-9-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: release the write-protect pin

Put the write-protect GPIO descriptor in nvmem_release() so that it can
be automatically released when the associated device's reference count
drops to 0.

Fixes: 2a127da461a9 ("nvmem: add support for the write-protect pin")
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Khouloud Touil <ktouil@baylibre.com>
Cc: stable <stable@vger.kernel.org>
[Bartosz: tweak the commit message]
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200310132257.23358-8-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: fix memory leak in error path

We need to free the ida mapping and nvmem struct if the write-protect
GPIO lookup fails.

Fixes: 2a127da461a9 ("nvmem: add support for the write-protect pin")
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200310132257.23358-7-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: add a newline for readability

Visibly separate the GPIO request from the previous operation in the
code with a newline.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200310132257.23358-6-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: remove a stray newline in nvmem_register()

Two newlines are unnecessary - remove one.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200310132257.23358-5-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add nvmem_cell_read_u64

Add nvmem_cell_read_u64() helper to ease read of an u64 value on consumer
side. This helper is useful on some sunxi platform that has 64 bits data
cells stored in no volatile memory.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200310132257.23358-4-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add nvmem_cell_read_common

Now there are nvmem_cell_read_u16 and nvmem_cell_read_u32.
They are very similar, let's strip out a common part.

And use nvmem_cell_read_common to simplify their implementation.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200310132257.23358-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix memory abort in cleanup path

nvmem_cell_info_to_nvmem_cell implementation has static
allocation of name. nvmem_add_cells_from_of() call may
return error and kfree name results in memory abort. Use
kstrdup_const() and kfree_const calls for name alloc and free.

Unable to handle kernel paging request at virtual address ffffffffffe44888
Mem abort info:
ESR = 0x96000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
swapper pgtable: 64k pages, 48-bit VAs, pgdp=00000000815d0000
[ffffffffffe44888] pgd=0000000081d30803, pud=0000000081d30803,
pmd=0000000000000000
Internal error: Oops: 96000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 2 PID: 43 Comm: kworker/2:1 Tainted
Hardware name: quill (DT)
Workqueue: events deferred_probe_work_func
pstate: a0000005 (NzCv daif -PAN -UAO)
pc : kfree+0x38/0x278
lr : nvmem_cell_drop+0x68/0x80
sp : ffff80001284f9d0
x29: ffff80001284f9d0 x28: ffff0001f677e830
x27: ffff800011b0b000 x26: ffff0001c36e1008
x25: ffff8000112ad000 x24: ffff8000112c9000
x23: ffffffffffffffea x22: ffff800010adc7f0
x21: ffffffffffe44880 x20: ffff800011b0b068
x19: ffff80001122d380 x18: ffffffffffffffff
x17: 00000000d5cb4756 x16: 0000000070b193b8
x15: ffff8000119538c8 x14: 0720072007200720
x13: 07200720076e0772 x12: 07750762072d0765
x11: 0773077507660765 x10: 072f073007300730
x9 : 0730073207380733 x8 : 0000000000000151
x7 : 07660765072f0720 x6 : ffff0001c00e0f00
x5 : 0000000000000000 x4 : ffff0001c0b43800
x3 : ffff800011b0b068 x2 : 0000000000000000
x1 : 0000000000000000 x0 : ffffffdfffe00000
Call trace:
kfree+0x38/0x278
nvmem_cell_drop+0x68/0x80
nvmem_device_remove_all_cells+0x2c/0x50
nvmem_register.part.9+0x520/0x628
devm_nvmem_register+0x48/0xa0
tegra_fuse_probe+0x140/0x1f0
platform_drv_probe+0x50/0xa0
really_probe+0x108/0x348
driver_probe_device+0x58/0x100
__device_attach_driver+0x90/0xb0
bus_for_each_drv+0x64/0xc8
__device_attach+0xd8/0x138
device_initial_probe+0x10/0x18
bus_probe_device+0x90/0x98
deferred_probe_work_func+0x74/0xb0
process_one_work+0x1e0/0x358
worker_thread+0x208/0x488
kthread+0x118/0x120
ret_from_fork+0x10/0x18
Code: d350feb5 f2dffbe0 aa1e03f6 8b151815 (f94006a0)
---[ end trace 49b1303c6b83198e ]---

Fixes: badcdff107cbf ("nvmem: Convert to using %pOFn instead of device_node.name")
Signed-off-by: Bitan Biswas <bbiswas@nvidia.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200109104017.6249-5-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: fix a 'makes pointer from integer without a cast' build warning

nvmem_register() returns a pointer, not a long int. Use ERR_CAST() to
cast the struct gpio_desc pointer to struct nvmem_device.

Reported-by: kbuild test robot <lkp@intel.com>
Fixes: 2a127da461a9 ("nvmem: add support for the write-protect pin")
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

nvmem: add support for the write-protect pin

The write-protect pin handling looks like a standard property that
could benefit other users if available in the core nvmem framework.

Instead of modifying all the memory drivers to check this pin, make
the NVMEM subsystem check if the write-protect GPIO being passed
through the nvmem_config or defined in the device tree and pull it
low whenever writing to the memory.

There was a suggestion for introducing the gpiodesc from pdata, but
as pdata is already removed it could be replaced by adding it to
nvmem_config.

Reference: https://lists.96boards.org/pipermail/dev/2018-August/001056.html

Signed-off-by: Khouloud Touil <ktouil@baylibre.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>

nvmem: core: add nvmem_device_find

nvmem_device_find provides a way to search for nvmem devices with
the help of a match function simlair to bus_find_device.

Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-rtc@vger.kernel.org
Cc: linux-serial@vger.kernel.org

drivers: Introduce device lookup variants by of_node

Introduce wrappers for {bus/driver/class}_find_device() to
locate devices by its of_node.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: dri-devel@lists.freedesktop.org
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: devicetree@vger.kernel.org
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: linux-i2c@vger.kernel.org
Cc: linux-rockchip@lists.infradead.org
Cc: linux-spi@vger.kernel.org
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Alan Tull <atull@kernel.org>
Cc: linux-fpga@vger.kernel.org
Cc: Peter Rosin <peda@axentia.se>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Heiner Kallweit <hkallweit1@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Thor Thayer <thor.thayer@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Peter Rosin <peda@axentia.se>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # I2C part
Acked-by: Moritz Fischer <mdf@kernel.org> # For FPGA part
Acked-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20190723221838.12024-3-suzuki.poulose@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

bus_find_device: Unify the match callback with class_find_device

There is an arbitrary difference between the prototypes of
bus_find_device() and class_find_device() preventing their callers
from passing the same pair of data and match() arguments to both of
them, which is the const qualifier used in the prototype of
class_find_device(). If that qualifier is also used in the
bus_find_device() prototype, it will be possible to pass the same
match() callback function to both bus_find_device() and
class_find_device(), which will allow some optimizations to be made in
order to avoid code duplication going forward. Also with that, constify
the "data" parameter as it is passed as a const to the match function.

For this reason, change the prototype of bus_find_device() to match
the prototype of class_find_device() and adjust its callers to use the
const qualifier in accordance with the new prototype of it.

Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Andreas Noever <andreas.noever@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Corey Minyard <minyard@acm.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: David Kershner <david.kershner@unisys.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: David Airlie <airlied@linux.ie>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Harald Freudenberger <freude@linux.ibm.com>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michael Jamet <michael.jamet@intel.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
Cc: Sebastian Ott <sebott@linux.ibm.com>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Yehezkel Bernat <YehezkelShB@gmail.com>
Cc: rafael@kernel.org
Acked-by: Corey Minyard <minyard@acm.org>
Acked-by: David Kershner <david.kershner@unisys.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Acked-by: Wolfram Sang <wsa@the-dreams.de> # for the I2C parts
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add NVMEM_SYSFS Kconfig

Many nvmem providers are not very keen on having default sysfs
nvmem entry, as most of the usecases for them are inside kernel
itself. And in some cases read/writes to some areas in nvmem are
restricted and trapped at secure monitor level, so accessing them
from userspace would result in board reboots.

This patch adds new NVMEM_SYSFS Kconfig to make binary sysfs entry
an optional one. This provision will give more flexibility to users.
This patch also moves existing sysfs code to a new file so that its
not compiled in when its not really required.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Gaurav Kohli <gkohli@codeaurora.org>
Tested-by: Gaurav Kohli <gkohli@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix read buffer in place

When the bit_offset in the cell is zero, the pointer to the msb will
not be properly initialized (ie, will still be pointing to the first
byte in the buffer).

This being the case, if there are bits to clear in the msb, those will
be left untouched while the mask will incorrectly clear bit positions
on the first byte.

This commit also makes sure that any byte unused in the cell is
cleared.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add nvmem_cell_read_u16

Add nvmem_cell_read_u16() helper to ease read of an u16 value on consumer
side. This is inspired by nvmem_cell_read_u32() function.
This helper is useful on stm32 that has 16 bits data cells stored in non
volatile memory.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: don't check the return value of notifier chain call

blocking_notifier_call_chain() returns the value returned by the last
registered callback. A positive return value doesn't indicate an error
and an nvmem device should correctly register irrespective of any
notifier callback failures. Drop the retval check.

Fixes: bee1138bea15 ("nvmem: add a notifier chain")
Cc: stable@vger.kernel.org
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Avoid useless iterations in nvmem_cell_get_from_lookup()

Once the correct cell has been found there is no need to continue
iterating, just stop there. While at it replace the goto used to leave
the loop with simple break statements.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Fix device reference leak

__nvmem_device_get() make use of bus_find_device() to get the relevant
device and this function increase the reference count of the device
found, however this is not accounted for anywhere. Fix
__nvmem_device_get() and __nvmem_device_put() to properly release this
reference count.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Always reference the device returned by nvmem_device_get()

In nvmem_device_get(), when the device lookup fails with DT it
currently fallback on nvmem_find() which is wrong for two reasons.
First nvmem_find() return NULL when nothing is found instead of an
ERR_PTR. But nvmem_find() also just lookup the device, it doesn't
reference the module and increment the reference count like it is done
in the DT path.

To fix this we replace the call to nvmem_find() with a call to
__nvmem_device_get() which does all the referencing and return a
proper ERR_PTR in case of error.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Properly handle connection ID in of_nvmem_device_get()

of_nvmem_device_get() would crash if NULL was passed as a connection
ID. Rework this to use the usual sementic of assuming the first
connection when no connection ID is given.

Furthermore of_nvmem_device_get() would return -EINVAL when it failed
to resolve the connection, making it impossible to properly implement
an optional connection. Return -ENOENT instead to let the caller know
that the connection doesn't exists.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Fix cell lookup when no cell is found

If the cell list is not empty and nvmem_find_cell_by_node/name() is
called for a cell that is not present in the list they will return an
invalid pointer instead of NULL. This happen because
list_for_each_entry() stop once it reach the list head again, but as
the list head is not contained in a struct nvmem_cell the iteration
variable then contains an invalid value.

This is easily solved by using a variable to iterate over the list and
one to return the cell found.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Fix of_nvmem_cell_get() for optional cells

of_nvmem_cell_get() should return -ENOENT when a cell isn't defined,
otherwise callers can't distinguish between a missing cell and other
errors.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Set the provider read-only when no write callback is given

If no write callback is given the device should be marked as read-only.
While at it also move from a bit or to a logical or as that is a logical
expression.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: add new config option

We want to add nvmem support for MTD. TI DaVinci is the first platform
that will be using it, but only in non-DT mode. In order not to
introduce any new interface to supporting of which we would have to
commit - add a new config option that tells nvmem not to use the DT
node of the parent device.

This way we won't be creating nvmem devices corresponding with MTD
partitions defined in device tree. By default MTD will set this new
field to true.

Once a set of bindings for MTD nvmem cells is agreed upon, we'll be
able to remove this option.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Move nvmem_type_str array to its only user

Since we put static variable to a header file it's copied to each module
that includes the header. But not all of them are actually using it.

Move nvmem_type_str array to its only user to make a compiler happy:

In file included from include/linux/rtc.h:18,
from drivers/rtc/rtc-proc.c:15:
include/linux/nvmem-provider.h:29:27: warning: 'nvmem_type_str'
defined but not used [-Wunused-const-variable=]
static const char * const nvmem_type_str[] = {
^~~~~~~~~~~~~~

Suggested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Suggested-by: Joe Perches <joe@perches.com>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: add type attribute

Add a type attribute so userspace is able to know how the data is stored as
this can help taking the correct decision when selecting which device to
use. This will also help program display the proper warnings when burning
fuses for example.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix regression in of_nvmem_cell_get()

NVMEM DT support seems to be totally broken after
commit e888d445ac33 ("nvmem: resolve cells from DT at registration time")
Fix this!

Index used in of_nvmem_cell_get() to find cell is specific to
consumer, It can not be used for searching the cell in provider.
Use device_node instead of this to find the matching cell in device
tree case.

Fixes: e888d445ac33 ("nvmem: resolve cells from DT at registration time")
Reported-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: hide unused nvmem_find_cell_by_index function

nvmem_find_cell_by_index() is only called from inside an #ifdef,
so we get a build warning without CONFIG_OF:

drivers/nvmem/core.c:496:1: error: 'nvmem_find_cell_by_index' defined but not used [-Werror=unused-function]

Move it into the same #ifdef as the caller to avoid the warning.

Fixes: e888d445ac33 ("nvmem: resolve cells from DT at registration time")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: fix nvmem_cell_get_from_lookup()

We check if the pointer returned by __nvmem_device_get() is not NULL
while we should actually check if it is not IS_ERR(nvmem). Fix it.

While we're at it: fix the next error path where we should assign an
error value to cell before returning.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Convert to using %pOFn instead of device_node.name

In preparation to remove the node name pointer from struct device_node,
convert printf users to use the %pOFn format specifier.

Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
[srinivas: rebased on top of next]
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: make nvmem_add_cells() static

Now we have new api nvmem_add/del_cell_table() we do not want users to use
nvmem_add_cells() anymore. So mark it accordingly. I guess it was missed in
original cleanup patch.

This also fixes below warning:
core.c:355:5: warning: no previous prototype for 'nvmem_add_cells'
[-Wmissing-prototypes]

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: use octal permissions instead of constants

Checkpatch emits a warning when using symbolic permissions. Use octal
permissions instead.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: fix commenting style

Remove a redundant '*/' as pointed out by checkpatch.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: make the naming of arguments in nvmem_cell_get() consistent

The argument representing the cell name in the nvmem_cell_get() family
of functions is not consistend between function prototypes and
definitions. Name it 'id' in all those routines. This is in line with
other frameworks and can represent both the DT cell name from the
nvmem-cell-names property as well as the con_id field from cell
lookup entries.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: use SPDX license identifiers

Use SPDX license identiefiers to core nvmem files and remove GPL 2.0
license boilerplate.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: add a notifier chain

Add a blocking notifier chain with four events (add and remove for
both devices and cells) so that users can get notified about the
addition of nvmem resources they're waiting for.

We'll use this instead of the at24 setup callback in the mityomapl138
board file.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: add support for cell lookups from machine code

Add a way for machine code users to associate devices with nvmem cells.

This restores the support for non-DT systems but following a different
approach. Cells must now be associated with devices using provided
routines and data structures before they can be retrieved using
nvmem_cell_get().

It's still possible to define cells statically in nvmem_config but
cells created this way still need to be associated with consumers using
lookup entries.

Note that nvmem_find() must be moved higher in the source file as we
want to call it from __nvmem_device_get() for devices that don't have
a device node.

The signature of __nvmem_device_get() is also changed as it's no longer
used to retrieve cells.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: resolve cells from DT at registration time

Currently we're creating a new cell structure everytime a DT user
calls nvmem_cell_get().

Change this behavior by resolving the cells during nvmem provider
registration and adding all cells to the provider's list. Make
of_nvmem_cell_get() just parse the phandle and look the cell up
in the relevant provider's list.

Don't drop the cell in nvmem_cell_put().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: add support for cell info

Add new structs and routines allowing users to define nvmem cells from
machine code. This global list of entries is parsed when a provider
is registered and cells are associated with the relevant nvmem_device
struct.

A possible improvement for the future is to allow users to register
cell tables after the nvmem provider has been registered by updating
the cell list at each call to nvmem_(add|del)_cell_table().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: remove the global cell list

Nvmem subsystem keeps a global list of cells that, for non-DT systems,
can only be referenced by cell name, which makes it impossible to have
more than one nvmem device with cells named the same.

This patch makes every nvmem device the owner of the list of its cells.
This effectively removes the support for non-DT systems, but it will
be reintroduced following a different approach in subsequent patches.

This isn't a problem as support for board files in nvmem is currently
broken anyway: any user that would try to get an nvmem cell from the
global cell list would remove the cell after the calling
nvmem_cell_put(). This can cause anything from a subsequent user not
being able to get the cell to double free errors if more users hold
reference to the same cell at the same time.

Fortunately there are no such users which allows us to rework this part.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: change the signature of nvmem_unregister()

We switched the nvmem framework to using kref instead of manually
checking the current number of users in nvmem_unregister() so this
function can no longer fail. We also converted all remaining users
that still checked the return value of nvmem_unregister() to using
devm_nvmem_register(). Make the routine return void.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: use kref

Use kref for reference counting. Use an approach similar to the one
seen in the common clock subsystem: don't actually destroy the nvmem
device until the last user puts it. This way we can get rid of the
users check from nvmem_unregister().

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: check the return value of nvmem_add_cells()

This function can fail so check its return value in nvmem_register()
and act accordingly.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: remove a stray newline

There are two empty lines between devm_nvmem_unregister() and
__nvmem_device_get(). Remove one.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: use list_for_each_entry_safe in nvmem_device_remove_all_cells()

Use the provided helper for iterating over list entries without having
to use the list_entry() macro.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: remove the name field from struct nvmem_device

This field is never set and is only used in a single error message.
Remove the field and use nvmem_dev_name() instead.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: provide nvmem_dev_name()

Kernel users don't have any means of checking the names of nvmem
devices. Add a routine that returns the name of the nvmem provider.

This will be useful for future nvmem notifier subscribers - otherwise
they can't check what device is being added/removed.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: return error code instead of NULL from nvmem_device_get

nvmem_device_get() should return ERR_PTR() on error or valid pointer
on success, but one of the code path seems to return NULL, so fix it.

Reported-by: Niklas Cassel <niklas.cassel@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: remove unused nvmem_device ncells member

nvmem ncells can be over written by calling nvmem_add_cells()
multiple times. I see there is no real point of maintaining count
of cells when we have a list of cell.

Remove this to avoid any confusion!

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Don't let a NULL cell_id for nvmem_cell_get() crash us

In commit ca04d9d3e1b1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on
Qcom chips") you can see a call like:

devm_nvmem_cell_get(dev, NULL);

Note that the cell ID passed to the function is NULL. This is because
the qcom-qusb2 driver is expected to work only on systems where the
PHY node is hooked up via device-tree and is nameless.

This works OK for the most part. The first thing nvmem_cell_get()
does is to call of_nvmem_cell_get() and there it's documented that a
NULL name is fine. The problem happens when the call to
of_nvmem_cell_get() returns -EINVAL. In such a case we'll fall back
to nvmem_cell_get_from_list() and eventually might (if nvmem_cells
isn't an empty list) crash with something that looks like:

strcmp
nvmem_find_cell
__nvmem_device_get
nvmem_cell_get_from_list
nvmem_cell_get
devm_nvmem_cell_get
qusb2_phy_probe

There are several different ways we could fix this problem:

One could argue that perhaps the qcom-qusb2 driver should be changed
to use of_nvmem_cell_get() which is allowed to have a NULL name. In
that case, we'd need to add a patche to introduce
devm_of_nvmem_cell_get() since the qcom-qusb2 driver is using devm
managed resources.

One could also argue that perhaps we could just add a name to
qcom-qusb2. That would be OK but I believe it effectively changes the
device tree bindings, so maybe it's a no-go.

In this patch I have chosen to fix the problem by simply not crashing
when a NULL cell_id is passed to nvmem_cell_get().

NOTE: that for the qcom-qusb2 driver the "nvmem-cells" property is
defined to be optional and thus it's expected to be a common case that
we would hit this crash and this is more than just a theoretical fix.

Fixes: ca04d9d3e1b1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips")
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: properly handle returned value nvmem_reg_read

Function nvmem_reg_read can return a non zero value indicating an error.
This returned value must be read and error propagated to
nvmem_cell_prepare_write_buffer. Silence the following gcc warning (W=1):

drivers/nvmem/core.c:1093:9: warning: variable 'rc' set but
not used [-Wunused-but-set-variable]

Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: describe add missing dev function parameter

Document dev parameter which not described in devm_nvmem_unregister
and devm_nvmem_register functions.

Fix below warnings when kernel is compiled with W=1
drivers/nvmem/core.c:579: warning: Function parameter or member
'dev' not described in 'devm_nvmem_register'
nvmem/core.c:615: warning: Function parameter or member 'dev'
not described in 'devm_nvmem_unregister'

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers: nvmem: Export nvmem_add_cells()

Not all platforms use device tree. It is useful to be able to add
cells to a NVMEM device from code. Export nvmem_add_cells() so making
this possible.

This required changing the parameters a bit, so that just the cells
and the number of cells are passed, not the whole nvmem config
structure.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Introduce devm_nvmem_(un)register()

Introduce devm_nvmem_register()/devm_nvmem_unregister() to make
.remove() unnecessary in trivial drivers.

Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: cphealy@gmail.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mediatek@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Cc: linux-amlogic@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Allow specifying device name verbatim

Add code to allow avoid having nvmem core append a numeric suffix to
the end of the name by passing config->id of -1.

Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: cphealy@gmail.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-mediatek@lists.infradead.org
Cc: linux-rockchip@lists.infradead.org
Cc: linux-amlogic@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: switch to device_property_present for reading property "read-only"

Switch to more generic device_property_present to consider also non-DT
properties.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: let stride and word_size default to 1

If the caller doesn't set stride and/or word_size in struct nvmem_config
then nvmem_register accepts this but we may face strange effects later
due to both values being 0. Therefore use 1 as default for both values.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Deduplicate bus_find_device() by name matching

No need to reinvent the wheel, we have bus_find_device_by_name().

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: set nvmem->owner to nvmem->dev->driver->owner if unset

All nvmem drivers are supposed to set the owner field of struct
nvmem_config, but this matches nvmem->dev->driver->owner.

As far as I see in drivers/nvmem/ directory, all the drivers are
the case. So, make nvmem_register() set the nvmem's owner to the
associated driver's owner unless nvmem_config sets otherwise.

Remove .owner settings in the drivers that are now redundant.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: remove unneeded IS_ENABLED(CONFIG_NVMEM) conditional

As you see in drivers/nvmem/Makefile, this C file is compiled only
when CONFIG_NVMEM is y or m.

So, IS_ENABLED(CONFIG_NVMEM) is always evaluated to 1 in this file.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: remove inline in drivers/nvmem/core.c

These two functions are defined in .c file, but called just once
(at least for now). So, the compiler will fold them into their
callers even without the "inline" markers.

However, this kind of optimization should not be done by hand.
It is compiler's judge after all.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: add missing of_node_put() in of_nvmem_cell_get()

of_get_next_parent() increments the refcount of the returned node.
It should be put when done.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: return EFBIG on out-of-range write

When writing data that exceeds the nvmem size to a nvmem sysfs file
using the sh redirection operator >, the shell hangs, trying to
write the out-of-range bytes endlessly.

Fix the problem by returning EFBIG described in man 2 write.

Similar change was done for binary sysfs files on commit
0936896056365349afa867c16e9f9100a6707cbf

Signed-off-by: Guy Shapiro <guy.shapiro@mobi-wize.com>
Cc: linux-api@vger.kernel.org
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: remove unneeded NULL check

"p" is the list iterator so it can't be NULL. Static checkers complain
about this unnecessary check because we dereference the list iterator to
get the next item in the list so we'd be in trouble if it really was
NULL. I have removed the check.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Add nvmem_cell_read_u32

This function does a quick and easy read of an u32 value without any
kind of resource management code on the consumer side.

Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
Reviewed-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Convert to using %pOF instead of full_name

Now that we have a custom printf format specifier, convert users of
full_name to use %pOF instead. This is preparation to remove storing
of the full path string for each node.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: add locking to nvmem_find_cell

Adding entries to nvmem_cells and deleting entries from it is
protected by nvmem_cells_mutex. Therefore this mutex should
also protect iterating over the list.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Call put_device() in nvmem_unregister()

Call put_device() in nvmem_unregister() to make sure nvmem_release
gets called freeing up allocated resources.

Cc: cphealy@gmail.com
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix leaks on registration errors

Make sure to deregister and release the nvmem device and underlying
memory on registration errors.

Note that the private data must be freed using put_device() once the
struct device has been initialised.

Also note that there's a related reference leak in the deregistration
function as reported by Mika Westerberg which is being fixed separately.

Fixes: b6c217ab9be6 ("nvmem: Add backwards compatibility support for older EEPROM drivers.")
Fixes: eace75cfdcf7 ("nvmem: Add a simple NVMEM framework for nvmem providers")
Cc: stable <stable@vger.kernel.org> # 4.3
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Acked-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Allow allocating several anonymous nvmem devices

Currently the nvmem core expect the config to provide a name and ID
that are then used to create the device name. When no device name is
given 'nvmem' is used. However if there is several such anonymous
devices they all get named 'nvmem0', which doesn't work.

To fix this problem use the ID from the config only when the config
also provides a name. When no name is provided take the uinque ID of
the nvmem device instead.

Signed-off-by: Aban Bedel <albeu@free.fr>
Reviewed-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Allow getting nvmem cell with a NULL cell id

The nvmem cell with a NULL cell name/id should be the one
with no accompanying 'nvmem-cell-names' property, and thus
will be the cell at index 0 in the device tree.
So, we default to index 0 and update the cell index only when
nvmem cell name id exists.

Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Correct a bunch of function documentations

Correct the documentation for arguments to a number
of functions.

Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Allow ignoring length when reading a cell

nvmem_cell_read() API fills in the argument 'len' with
the number of bytes read from the cell. Many users don't
care about this length value. So allow users to pass a
NULL pointer to this len field.

Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: fix nvmem_cell_read() return type doc

nvmem_cell_read() returns void *, not char *. This is a cleanup that got
left out of commit a6c50912508d ("nvmem: Declare nvmem_cell_read()
consistently").

Signed-off-by: Brian Norris <briannorris@chromium.org>
Fixes: a6c50912508d ("nvmem: Declare nvmem_cell_read() consistently")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

remove lots of IS_ERR_VALUE abuses

Most users of IS_ERR_VALUE() in the kernel are wrong, as they
pass an 'int' into a function that takes an 'unsigned long'
argument. This happens to work because the type is sign-extended
on 64-bit architectures before it gets converted into an
unsigned type.

However, anything that passes an 'unsigned short' or 'unsigned int'
argument into IS_ERR_VALUE() is guaranteed to be broken, as are
8-bit integers and types that are wider than 'unsigned long'.

Andrzej Hajda has already fixed a lot of the worst abusers that
were causing actual bugs, but it would be nice to prevent any
users that are not passing 'unsigned long' arguments.

This patch changes all users of IS_ERR_VALUE() that I could find
on 32-bit ARM randconfig builds and x86 allmodconfig. For the
moment, this doesn't change the definition of IS_ERR_VALUE()
because there are probably still architecture specific users
elsewhere.

Almost all the warnings I got are for files that are better off
using 'if (err)' or 'if (err < 0)'.
The only legitimate user I could find that we get a warning for
is the (32-bit only) freescale fman driver, so I did not remove
the IS_ERR_VALUE() there but changed the type to 'unsigned long'.
For 9pfs, I just worked around one user whose calling conventions
are so obscure that I did not dare change the behavior.

I was using this definition for testing:

#define IS_ERR_VALUE(x) ((unsigned long*)NULL == (typeof (x)*)NULL && \
unlikely((unsigned long long)(x) >= (unsigned long long)(typeof(x))-MAX_ERRNO))

which ends up making all 16-bit or wider types work correctly with
the most plausible interpretation of what IS_ERR_VALUE() was supposed
to return according to its users, but also causes a compile-time
warning for any users that do not pass an 'unsigned long' argument.

I suggested this approach earlier this year, but back then we ended
up deciding to just fix the users that are obviously broken. After
the initial warning that caused me to get involved in the discussion
(fs/gfs2/dir.c) showed up again in the mainline kernel, Linus
asked me to send the whole thing again.

[ Updated the 9p parts as per Al Viro - Linus ]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.org/lkml/2016/1/7/363
Link: https://lkml.org/lkml/2016/5/27/486
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> # For nvmem part
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

nvmem: core: remove regmap dependency

nvmem uses regmap_raw_read/write apis to read/write data from providers,
regmap raw apis stopped working with recent kernels which removed raw
accessors on mmio bus. This resulted in broken nvmem for providers
which are based on regmap mmio bus. This issue can be fixed temporarly
by moving to other regmap apis, but we might hit same issue in future.
Moving to interfaces based on read/write callbacks from providers would
be more robust.

This patch removes regmap dependency from nvmem and introduces
read/write callbacks from the providers.

Without this patch nvmem providers like qfprom based on regmap mmio
bus would not work.

Reported-by: Rajendra Nayak <rjendra@qti.qualcomm.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Add backwards compatibility support for older EEPROM drivers.

Older drivers made an 'eeprom' file available in the /sys device
directory. Have the NVMEM core provide this to retain backwards
compatibility.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Add flag to export NVMEM to root only

Legacy AT24, AT25 EEPROMs are exported in sys so that only root can
read the contents. The EEPROMs may contain sensitive information. Add
a flag so the provide can indicate that NVMEM should also restrict
access to root only.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix error path in nvmem_add_cells()

The current code fails to nvmem_cell_drop(cells[0]) - even worse, if
the loop above fails already at i==0, we'll enter an essentially
infinite loop doing nvmem_cell_drop on cells[-1], cells[-2], ... which
is unlikely to end well.

Also, we're not freeing the temporary backing array cells on the error
path.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: return error for non word aligned access

nvmem providers have restrictions on register strides, so return error
when users attempt to read/write buffers with sizes which are less
than word size.

Without this patch the userspace would continue to try as it does not
get any error from the nvmem core, resulting in a hang or endless loop
in userspace.

Reported-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: return error for non word aligned access

nvmem providers have restrictions on register strides, so return error
when users attempt to read/write buffers with sizes which are less
than word size.

Without this patch the userspace would continue to try as it does not
get any error from the nvmem core, resulting in a hang or endless loop
in userspace.

Reported-by: Ariel D'Alessandro <ariel@vanguardiasur.com.ar>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Fix memory leak in nvmem_cell_write

A tmp buffer is allocated if cell->bit_offset || cell->nbits.
So the tmp buffer needs to be freed at the same condition to avoid leak.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: Handle shift bits in-place if cell->nbits is non-zero

It's pointless to test (cell->bit_offset || cell->bit_offset).
nvmem_shift_read_buffer_in_place() should be called when
(cell->bit_offset || cell->nbits).

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: core: fix the out-of-range leak in read/write()

The position to read/write must be less than max
register size.

Signed-off-by: ZhengShunQian <zhengsq@rock-chips.com>
Acked-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Add nvmem_device based consumer apis.

This patch adds read/write apis which are based on nvmem_device. It is
common that the drivers like omap cape manager or qcom cpr driver to
access bytes directly at particular offset in the eeprom and not from
nvmem cell info in DT. These driver would need to get access to the nvmem
directly, which is what these new APIS provide.

These wrapper apis would help such users to avoid code duplication in
there drivers and also avoid them reading a big eeprom blob and parsing
it internally in there driver.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Add a simple NVMEM framework for consumers

This patch adds just consumers part of the framework just to enable easy
review.

Up until now, nvmem drivers were stored in drivers/misc, where they all
had to duplicate pretty much the same code to register a sysfs file,
allow in-kernel users to access the content of the devices they were
driving, etc.

This was also a problem as far as other in-kernel users were involved,
since the solutions used were pretty much different from on driver to
another, there was a rather big abstraction leak.

This introduction of this framework aims at solving this. It also
introduces DT representation for consumer devices to go get the data they
require (MAC Addresses, SoC/Revision ID, part numbers, and so on) from
the nvmems.

Having regmap interface to this framework would give much better
abstraction for nvmems on different buses.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
[Maxime Ripard: intial version of the framework]
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

nvmem: Add a simple NVMEM framework for nvmem providers

This patch adds just providers part of the framework just to enable easy
review.

Up until now, NVMEM drivers like eeprom were stored in drivers/misc,
where they all had to duplicate pretty much the same code to register
a sysfs file, allow in-kernel users to access the content of the devices
they were driving, etc.

This was also a problem as far as other in-kernel users were involved,
since the solutions used were pretty much different from on driver to
another, there was a rather big abstraction leak.

This introduction of this framework aims at solving this. It also
introduces DT representation for consumer devices to go get the data
they require (MAC Addresses, SoC/Revision ID, part numbers, and so on)
from the nvmems.

Having regmap interface to this framework would give much better
abstraction for nvmems on different buses.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
[Maxime Ripard: intial version of eeprom framework]
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de>
Tested-by: Rajendra Nayak <rnayak@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>