regmap: rework ->max_register handling

When regmap consists of single register, 'regmap' subsystem is unable to
understand whether ->max_register is set or not, because in both cases it
is equal to zero. It leads to that the logic based on value of
->max_register doesn't work. For example using of REGCACHE_FLAT fails.

This patch introduces an extra parameter to regmap config, indicating
that zero value in ->max_register is authentic.

Signed-off-by: Jan Dakinevich <jan.dakinevich@salutedevices.com>
Link: https://lore.kernel.org/r/20240126200836.1829995-1-jan.dakinevich@salutedevices.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: fix bogus error on regcache_sync success

Since commit 0ec7731655de ("regmap: Ensure range selector registers
are updated after cache sync") opening pcm512x based soundcards fail
with EINVAL and dmesg shows sync cache and pm_runtime_get errors:

[ 228.794676] pcm512x 1-004c: Failed to sync cache: -22
[ 228.794740] pcm512x 1-004c: ASoC: error at snd_soc_pcm_component_pm_runtime_get on pcm512x.1-004c: -22

This is caused by the cache check result leaking out into the
regcache_sync return value.

Fix this by making the check local-only, as the comment above the
regcache_read call states a non-zero return value means there's
nothing to do so the return value should not be altered.

Fixes: 0ec7731655de ("regmap: Ensure range selector registers are updated after cache sync")
Cc: stable@vger.kernel.org
Signed-off-by: Matthias Reichl <hias@horus.com>
Link: https://lore.kernel.org/r/20231203222216.96547-1-hias@horus.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Ensure range selector registers are updated after cache sync

When we sync the register cache we do so with the cache bypassed in order
to avoid overhead from writing the synced values back into the cache. If
the regmap has ranges and the selector register for those ranges is in a
register which is cached this has the unfortunate side effect of meaning
that the physical and cached copies of the selector register can be out of
sync after a cache sync. The cache will have whatever the selector was when
the sync started and the hardware will have the selector for the register
that was synced last.

Fix this by rewriting all cached selector registers after every sync,
ensuring that the hardware and cache have the same content. This will
result in extra writes that wouldn't otherwise be needed but is simple
so hopefully robust. We don't read from the hardware since not all
devices have physical read support.

Given that nobody noticed this until now it is likely that we are rarely if
ever hitting this case.

Reported-by: Hector Martin <marcan@marcan.st>
Cc: stable@vger.kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20231026-regmap-fix-selector-sync-v1-1-633ded82770d@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Let users check if a register is cached

The HDA driver has a use case for checking if a register is cached which
it bodges in awkwardly and unclearly. Provide an API which allows it to
directly do what it's trying to do.

Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230717-regmap-cache-check-v1-1-73ef688afae3@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Revert "Add 64-bit mode support"

There is no support for 64-bit data size in regmap, so
there is no point to have it in regmap cache.

This reverts commit 8b7663de6e2bfe3c40e1846e1c4625f33d138757.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230622183613.58762-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regcache: Push async I/O request down into the rbtree cache

Currently the regcache core unconditionally enables async I/O for all cache
types, causing problems for the maple tree cache which dynamically allocates
the buffers used to write registers to the device since async requires the
buffers to be kept around until the I/O has been completed.

This use of async I/O is mainly for the rbtree cache which stores data in
a format directly usable for regmap_raw_write(), though there is a special
case for single register writes which would also have allowed it to be used
with the flat cache. It is a bit of a landmine for other caches since it
implicitly converts sync operations to async, and with modern hardware it
is not clear that async I/O is actually a performance win as shown by the
performance work David Jander did with SPI. In multi core systems the cost
of managing concurrency ends up swamping the performance benefit and almost
all modern systems are multi core.

Address this by pushing the enablement of async I/O down into the rbtree
cache where it is actively used, avoiding surprises for other cache
implementations.

Reported-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Fixes: bfa0b38c1483 ("regmap: maple: Implement block sync for the maple tree cache")
Reviewed-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Tested-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230719-regcache-async-rbtree-v1-1-b03d30cf1daf@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: regcache: Don't sync read-only registers

regcache_maple_sync() tries to sync all cached values no matter
whether it's writable or not. OTOH, regache_sync_val() does care the
wrtability and returns -EIO for a read-only register. This results in
an error message like:
snd_hda_codec_realtek hdaudioC0D0: Unable to sync register 0x2f0009. -5
and the sync loop is aborted incompletely.

This patch adds the writable register check to regcache_sync_val() for
addressing the bug above.

Note that, although we may add the check in the caller side
(regcache_maple_sync()), here we put in regcache_sync_val(), so that a
similar case like this can be avoided in future.

Fixes: f033c26de5a5 ("regmap: Add maple tree based register cache")
Link: https://lore.kernel.org/r/877cs7g6f1.wl-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20230613112240.3361-1-tiwai@suse.de
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Don't check for changes in regcache_set_val()

The only user of regcache_set_val() ignores the return value so we may as
well not bother checking if the value we are trying to set is the same as
the value already stored.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230609-regcache-set-val-no-ret-v1-1-9a6932760cf8@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: maple: Implement block sync for the maple tree cache

For register maps where we can write multiple values in a single bus
operation it is generally much faster to do so. Improve the performance of
maple tree cache syncs on such devices by identifying blocks of adjacent
registers that need to be written out and combining them into a single
operation.

Combining writes does mean that we need to allocate a scratch buffer and
format the data into it but it is expected that for most cases where caches
are in use the cost of I/O will be much greater than the cost of doing the
allocation and format.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230609-regcache-maple-sync-raw-v1-1-8ddeb4e2b9ab@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Add maple tree based register cache

The current state of the art for sparse register maps is the
rbtree cache. This works well for most applications but isn't
always ideal for sparser register maps since the rbtree can get
deep, requiring a lot of walking. Fortunately the kernel has a
data structure intended to address this very problem, the maple
tree. Provide an initial implementation of a register cache
based on the maple tree to start taking advantage of it.

The entries stored in the maple tree are arrays of register
values, with the maple tree keys holding the register addresses.
We store data in host native format rather than device native
format as we do for rbtree, this will be a benefit for devices
where we don't marshal data within regmap and simplifies the code
but will result in additional CPU overhead when syncing the cache
on devices where we do marshal data in regmap.

This should work well for a lot of devices, though there's some
additional areas that could be looked at such as caching the
last accessed entry like we do for rbtree and trying to minimise
the maple tree level locking. We should also use bulk writes
rather than single register writes when resyncing the cache where
possible, even if we don't store in device native format.

Very small register maps may continue to to better with rbtree
longer term.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230325-regcache-maple-v3-2-23e271f93dc7@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Factor out single value register syncing

In order to support sparse caches that don't store data in raw format
factor out the parts of the raw block sync implementation that deal with
writing a single register via _regmap_write().

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230325-regcache-maple-v3-1-23e271f93dc7@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Removed compressed cache support

The compressed register cache support has assumptions that make it hard to
cover in testing, mainly that it requires raw registers defaults be
provided. Rather than either address these assumptions or leave it untested
by the forthcoming KUnit tests let's remove it, the use case is quite thin
and there are no current users.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230324-regcache-lzo-v1-1-08c5d63e2a5e@kernel.org

regmap: Clarify error for unknown cache types

The error message printed when we fail to locate the cache type the map
requested says it can't find a compress type rather than a cache type,
fix that. Since the compressed type is the only one currently compiled
conditionally it's likely to be the missing type but that might not always
be true and is still unclear.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230324-regcache-unknown-v1-1-80deecbf196b@kernel.org

regmap: Handle sparse caches in the default sync

If there is no cache entry available we will get -ENOENT from the cache
implementation, handle this gracefully and skip rather than treating it as
an error.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20230325-regcache-sparse-sync-v1-1-2a890239d061@kernel.org

regmap: cache: Silence checkpatch warning

checkpatch.pl warned:
WARNING: ENOSYS means 'invalid syscall nr' and nothing else
Align the return value to regcache_drop_region().

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/20230313071812.13577-2-alexander.stein@ew.tq-group.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Return error in cache sync operations for REGCACHE_NONE

There is no sense in doing a cache sync on REGCACHE_NONE regmaps.
Instead of panicking the kernel due to missing cache_ops, return an error
to client driver.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Link: https://lore.kernel.org/r/20230313071812.13577-1-alexander.stein@ew.tq-group.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Add extra parameter check in regcache_init

When num_reg_defaults > 0 but reg_defaults is NULL, there will be a
NULL pointer exception.

Current code has no such usage, but as additional hardening, also
check this to prevent any chance of crashing.

Signed-off-by: Schspa Shi <schspa@gmail.com>
Link: https://lore.kernel.org/r/20220629130951.63040-1-schspa@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Don't warn about cache only mode for devices with no cache

For devices with no cache it can make sense to use cache only mode as a
mechanism for trapping writes to hardware which is inaccessible but since
no cache is equivalent to cache bypass we force such devices into bypass
mode. This means that our check that bypass and cache only mode aren't both
enabled simultanously is less sensible for devices without a cache so relax
it.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220622171723.1235749-1-broonie@kernel.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Fix syntax errors in comments

Delete the redundant word 'the'.

Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Link: https://lore.kernel.org/r/20220604041603.9697-1-wangxiang@cdjrlc.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: set max_register with reg_stride

Current logic does not consider multi-stride cases,
the max_register have to calculate with reg_stride
because it is a kind of address range.

Signed-off-by: Jeongtae Park <jtp.park@samsung.com>
Link: https://lore.kernel.org/r/20220425114613.15934-1-jtp.park@samsung.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Assign boolean values to a bool variable

Fix the following coccicheck warnings:

./drivers/base/regmap/regcache.c:71:3-18: WARNING: Assignment of
0/1 to bool variable.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Zhong <abaci-bugfix@linux.alibaba.com>
Link: https://lore.kernel.org/r/1611215961-33725-1-git-send-email-abaci-bugfix@linux.alibaba.com
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: fix page selection for noinc writes

Non-incrementing writes can fail if register + length crosses page
border. However for non-incrementing writes we should not check for page
border crossing. Fix this by passing additional flag to _regmap_raw_write
and passing length to _regmap_select_page basing on the flag.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Fixes: cdf6b11daa77 ("regmap: Add regmap_noinc_write API")
Link: https://lore.kernel.org/r/20200917153405.3139200-2-dmitry.baryshkov@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: add proper SPDX identifiers on files that did not have them.

There were a few files in the regmap code that did not have SPDX
identifiers on them, so fix that up. At the same time, remove the "free
form" text that specified the license of the file, as that is impossible
for any tool to properly parse.

Also, as Mark loves // comment markers, convert all of the headers to be
the same to make things look consistent :)

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Fix typo in IS_ENABLED() check

Reported-by: Andreas Ziegler <andreas.ziegler@fau.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: make LZO cache optional

Commit 2cbbb579bcbe3 ("regmap: Add the LZO cache support") added support
for LZO compression in regcache, but there were never any users added
afterwards. Since LZO support itself has its own size, it currently is
rather a deoptimization.

So make it optional by introducing a symbol that can be selected by
drivers wanting to make use of it.

Saves e.g. ~46 kB on MIPS (size of LZO support + regcache LZO code).

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Fixup the kernel-doc comments on functions/structures

Most of the kernel-doc comments in regmap don't actually generate
correctly. This patch fixes up a few common issues, corrects some typos
and adds some missing argument descriptions.

The most common issues being using a : after the function name which
causes the short description to not render correctly and not separating
the long and short descriptions of the function. There are quite a few
instances of arguments not being described or given the wrong name as
well.

This patch doesn't fixup functions/structures that are currently missing
descriptions.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Fix num_reg_defaults computation from reg_defaults_raw

In 3245d460 (regmap: cache: Fall back to register by register read for
cache defaults) non-readable registers are skipped when initializing
reg_defaults, but are still included in num_reg_defaults. So there can
be uninitialized entries at the end of reg_defaults, which can cause
problems when the register cache initializes from the full array.

Fixed it by excluding non-readable registers from the count as well.

Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Fix typo in cache_bypass parameter description

Setting the flag 'cache_bypass' will bypass the cache not the hardware.
Fix this comment here.

Fixes: 0eef6b0415f5 ("regmap: Fix doc comment")
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Fall back to register by register read for cache defaults

If we are unable to read the cache defaults for a regmap then fall back
on attempting to read them word by word. This is going to be painfully
slow for large regmaps but might be adequate for smaller ones.

Signed-off-by: Mark Brown <broonie@kernel.org>
[maciej: Use cache_bypass around read and skipping of unreadable regs]
Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Tested-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: pass buffer size to regmap_raw_read() in regcache_hw_init()

regcache_hw_init() uses regmap_raw_read() to initialize cache
when reg_defaults_raw isn't provided.

The last parameter to regmap_raw_read() is buffer size in bytes,
however regcache_hw_init() called it with number of registers
to read instead, which cause problem if they aren't one byte
wide in cache.

This wasn't triggered by any of current in-tree drivers
since they either have one-byte registers or provide
reg_defaults_raw explicitly.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Move the num_reg_defaults check as early as possible

If the register defaults are provided by the driver without the
number by mistake, it should just return an error with one promotion.

This should be as early as possible, then there is no need to verify
the register defaults' stride and the other code followed.

Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Add warning info for the cache check

If there is no cache used for the drivers, the register defaults
or the register defaults raw are not need any more. This patch
will check this and print a warning.

Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Add 64-bit mode support

Since the mmio has support the 64-bit has been supported for the
64-bit platform, so should the regcache core too.

Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: To suppress the noise of checkpatch

There will be some warning like the following when checking new
patches near this code:
"WARNING: Missing a blank line after declarations"
This patch will suppress this warning.

Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

debugfs: Pass bool pointer to debugfs_create_bool()

Its a bit odd that debugfs_create_bool() takes 'u32 *' as an argument,
when all it needs is a boolean pointer.

It would be better to update this API to make it accept 'bool *'
instead, as that will make it more consistent and often more convenient.
Over that bool takes just a byte.

That required updates to all user sites as well, in the same commit
updating the API. regmap core was also using
debugfs_{read|write}_file_bool(), directly and variable types were
updated for that to be bool as well.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

regmap: Split use_single_rw internally into use_single_read/write

use_single_rw currently reflects the capabilities of the connected
device. The capabilities of the bus are currently missing for this
variable.

As there are read only and write only buses we need seperate values for
use_single_rw to also reflect tha capabilities of the bus.

This patch splits use_single_rw into use_single_read and
use_single_write. The initialization is changed to check the
configuration for use_single_rw and to check the capabilities of the
used bus.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Use regcache_mark_dirty() to indicate power loss or reset

Existing regmap users call regcache_mark_dirty() as part of the
suspend/resume sequence, to tell regcache that non-default values need to
be resynced post-resume. Add an internal "no_sync_defaults" regmap flag
to remember this state, so that regcache_sync() can differentiate between
these two cases:

1) HW was reset, so any cache values that match map->reg_defaults can be
safely skipped. On some chips there are a lot of registers in the
reg_defaults list, so this optimization speeds things up quite a bit.

2) HW was not reset (maybe it was just clock-gated), so if we cached
any writes, they should be sent to the hardware regardless of whether
they match the HW default. Currently this will write out all values in
the regcache, since we don't maintain per-register dirty bits.

Suggested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Add a helper function for regcache sync test

We're going to add another "does this register need syncing?" check, so
rather than repeating it in three places, we'll separate all of the
relevant logic into a helper function.

Signed-off-by: Kevin Cernekee <cernekee@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Move tracing header into drivers/base/regmap

The tracing events for regmap are confined to the regmap subsystem. It
also requires accessing an internal header. Instead of including the
internal header from a generic file location, move the tracing file
into the regmap directory.

Also rename the regmap tracing header to trace.h, as it is redundant to
keep the regmap.h name when it is in the regmap directory.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: introduce regmap_name to fix syscon regmap trace events

This patch fixes a NULL pointer dereference when enabling regmap event
tracing in the presence of a syscon regmap, introduced by commit bdb0066df96e
("mfd: syscon: Decouple syscon interface from platform devices").
That patch introduced syscon regmaps that have their dev field set to NULL.
The regmap trace events expect it to point to a valid struct device and feed
it to dev_name():

$ echo 1 > /sys/kernel/debug/tracing/events/regmap/enable

Unable to handle kernel NULL pointer dereference at virtual address 0000002c
pgd = 80004000
[0000002c] *pgd=00000000
Internal error: Oops: 17 [#1] SMP ARM
Modules linked in: coda videobuf2_vmalloc
CPU: 0 PID: 304 Comm: kworker/0:2 Not tainted 4.0.0-rc2+ #9197
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
Workqueue: events_freezable thermal_zone_device_check
task: 9f25a200 ti: 9f1ee000 task.ti: 9f1ee000
PC is at ftrace_raw_event_regmap_block+0x3c/0xe4
LR is at _regmap_raw_read+0x1bc/0x1cc
pc : [<803636e8>] lr : [<80365f2c>] psr: 600f0093
sp : 9f1efd78 ip : 9f1efdb8 fp : 9f1efdb4
r10: 00000004 r9 : 00000001 r8 : 00000001
r7 : 00000180 r6 : 00000000 r5 : 9f00e3c0 r4 : 00000003
r3 : 00000001 r2 : 00000180 r1 : 00000000 r0 : 9f00e3c0
Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c5387d Table: 2d91004a DAC: 00000015
Process kworker/0:2 (pid: 304, stack limit = 0x9f1ee210)
Stack: (0x9f1efd78 to 0x9f1f0000)
fd60: 9f1efda4 9f1efd88
fd80: 800708c0 805f9510 80927140 800f0013 9f1fc800 9eb2f490 00000000 00000180
fda0: 808e3840 00000001 9f1efdfc 9f1efdb8 80365f2c 803636b8 805f8958 800708e0
fdc0: a00f0013 803636ac 9f16de00 00000180 80927140 9f1fc800 9f1fc800 9f1efe6c
fde0: 9f1efe6c 9f732400 00000000 00000000 9f1efe1c 9f1efe00 80365f70 80365d7c
fe00: 80365f3c 9f1fc800 9f1fc800 00000180 9f1efe44 9f1efe20 803656a4 80365f48
fe20: 9f1fc800 00000180 9f1efe6c 9f1efe6c 9f732400 00000000 9f1efe64 9f1efe48
fe40: 803657bc 80365634 00000001 9e95f910 9f1fc800 9f1efeb4 9f1efe8c 9f1efe68
fe60: 80452ac0 80365778 9f1efe8c 9f1efe78 9e93d400 9e93d5e8 9f1efeb4 9f72ef40
fe80: 9f1efeac 9f1efe90 8044e11c 80452998 8045298c 9e93d608 9e93d400 808e1978
fea0: 9f1efecc 9f1efeb0 8044fd14 8044e0d0 ffffffff 9f25a200 9e93d608 9e481380
fec0: 9f1efedc 9f1efed0 8044fde8 8044fcec 9f1eff1c 9f1efee0 80038d50 8044fdd8
fee0: 9f1ee020 9f72ef40 9e481398 00000000 00000008 9f72ef54 9f1ee020 9f72ef40
ff00: 9e481398 9e481380 00000008 9f72ef40 9f1eff5c 9f1eff20 80039754 80038bfc
ff20: 00000000 9e481380 80894100 808e1662 00000000 9e4f2ec0 00000000 9e481380
ff40: 800396f8 00000000 00000000 00000000 9f1effac 9f1eff60 8003e020 80039704
ff60: ffffffff 00000000 ffffffff 9e481380 00000000 00000000 9f1eff78 9f1eff78
ff80: 00000000 00000000 9f1eff88 9f1eff88 9e4f2ec0 8003df30 00000000 00000000
ffa0: 00000000 9f1effb0 8000eb60 8003df3c 00000000 00000000 00000000 00000000
ffc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
ffe0: 00000000 00000000 00000000 00000000 00000013 00000000 ffffffff ffffffff
Backtrace:
[<803636ac>] (ftrace_raw_event_regmap_block) from [<80365f2c>] (_regmap_raw_read+0x1bc/0x1cc)
r9:00000001 r8:808e3840 r7:00000180 r6:00000000 r5:9eb2f490 r4:9f1fc800
[<80365d70>] (_regmap_raw_read) from [<80365f70>] (_regmap_bus_read+0x34/0x6c)
r10:00000000 r9:00000000 r8:9f732400 r7:9f1efe6c r6:9f1efe6c r5:9f1fc800
r4:9f1fc800
[<80365f3c>] (_regmap_bus_read) from [<803656a4>] (_regmap_read+0x7c/0x144)
r6:00000180 r5:9f1fc800 r4:9f1fc800 r3:80365f3c
[<80365628>] (_regmap_read) from [<803657bc>] (regmap_read+0x50/0x70)
r9:00000000 r8:9f732400 r7:9f1efe6c r6:9f1efe6c r5:00000180 r4:9f1fc800
[<8036576c>] (regmap_read) from [<80452ac0>] (imx_get_temp+0x134/0x1a4)
r6:9f1efeb4 r5:9f1fc800 r4:9e95f910 r3:00000001
[<8045298c>] (imx_get_temp) from [<8044e11c>] (thermal_zone_get_temp+0x58/0x74)
r7:9f72ef40 r6:9f1efeb4 r5:9e93d5e8 r4:9e93d400
[<8044e0c4>] (thermal_zone_get_temp) from [<8044fd14>] (thermal_zone_device_update+0x34/0xec)
r6:808e1978 r5:9e93d400 r4:9e93d608 r3:8045298c
[<8044fce0>] (thermal_zone_device_update) from [<8044fde8>] (thermal_zone_device_check+0x1c/0x20)
r5:9e481380 r4:9e93d608
[<8044fdcc>] (thermal_zone_device_check) from [<80038d50>] (process_one_work+0x160/0x3d4)
[<80038bf0>] (process_one_work) from [<80039754>] (worker_thread+0x5c/0x4f4)
r10:9f72ef40 r9:00000008 r8:9e481380 r7:9e481398 r6:9f72ef40 r5:9f1ee020
r4:9f72ef54
[<800396f8>] (worker_thread) from [<8003e020>] (kthread+0xf0/0x108)
r10:00000000 r9:00000000 r8:00000000 r7:800396f8 r6:9e481380 r5:00000000
r4:9e4f2ec0
[<8003df30>] (kthread) from [<8000eb60>] (ret_from_fork+0x14/0x34)
r7:00000000 r6:00000000 r5:8003df30 r4:9e4f2ec0
Code: e3140040 1a00001a e3140020 1a000016 (e596002c)
---[ end trace 193c15c2494ec960 ]---

Fixes: bdb0066df96e (mfd: syscon: Decouple syscon interface from platform devices)
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

regmap: Skip read-only registers in regcache_sync()

regcache_sync() spews warnings when a value was cached for a read-only
register as it tries to write all registers no matter whether they are
writable or not. This patch adds regmap_wrtieable() checks for
avoiding it in regcache_sync_block_single() and regcache_block_raw().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Sort include headers alphabetically

If the inlcude headers aren't sorted alphabetically, then the
logical choice is to append new ones, however that creates a
lot of potential for conflicts or duplicates because every change
will then add new includes in the same location.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Fix possible ZERO_SIZE_PTR pointer dereferencing error.

When all the registers are volatile(unlikely, but logically and mostly
will happen for some 'device' who has very few registers), then the
count will be euqal to 0, then kmalloc() will return ZERO_SIZE_PTR,
which equals to ((void *)16).

So this patch fix this with just doing the zero check before calling
kmalloc(). If the count == 0, so we can make sure that all the registers
are volatile, so no cache is need.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: use kmalloc_array instead of kmalloc

This patch fixes checkpatch.pl warning for regmap cache.
WARNING : prefer kmalloc_array over kmalloc with multiply

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: speed regcache_hw_init() up.

This may speed regcache_hw_init() up for some cases that there
has volatile registers.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: fix errno in regcache_hw_init()

When kmalloc() fails, we should return -ENOMEM.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: cleanup regcache_hw_init()

Remove the redundant code for regmap cache.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: fix errno in regcache_hw_init()

When kmalloc() fails, we should return -ENOMEM.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: cache: Do not fail silently from regcache_sync calls

Call stack of regcache_sync calls may not emit any error message even if
operation was cancelled due an error in I/O driver. One such a silent error
is for instance if I2C bus driver doesn't receive ACK from the I2C device
and returns -EREMOTEIO.

Since many users of regcache_sync() don't check and print the error there is
no any indication that HW registers are potentially out of sync.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

regmap: Don't attempt block writes when syncing cache on single_rw devices

If the device can't support block writes then don't attempt to use raw
syncing which will automatically generate block writes for adjacent
registers, use the existing _single() block syncing implementation.

Reported-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org

regmap: cache: Don't attempt to sync non-writeable registers

In the regcache_default_sync, if a register isn't writeable, then
_regmap_write will return an error and the rest of the sync will be
aborted. Avoid this by checking if a register is writeable before
trying to sync it.

Signed-off-by: Dylan Reid <dgreid@chromium.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

regmap: cache: Step by stride in default sync

The default sync operation was still assuming a stride of one, fix it
to respect the reg_stride set in the map.

Signed-off-by: Dylan Reid <dgreid@chromium.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

regmap: Check stride of register patch as we register it

Currently, we check the registers in the patch are aligned to the
register stride everytime we sync the cache and the first time the patch
is written out is unchecked.

This patch checks the register patch when we first register it so the
first writes are no longer unchecked and then doesn't check on
subsequent syncs as the patch will be unchanged.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

regmap: cache: Handle stride > 1 in sync_block_raw_flush

regcache_sync_block_raw_flush takes the address of the base register
and the address of one past the last register to write to. "count" is
the number of registers in the range, not the number of bytes, it
should be (end addr - start addr) / stride. Without accounting for
strides greater than one, registers past the end might be synced or
the writeable_reg callback at the beginning of _regmap_raw_write will
fail and nothing will be written.

Signed-off-by: Dylan Reid <dgreid@chromium.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

regmap: Use async I/O during cache sync

Try to speed up I/O a little by not synchronising until we are finished
scheduling writes. A brief survey of existing users suggests we have none
that would currently benefit from an async cache sync.

Signed-off-by: Mark Brown <broonie@linaro.org>

regmap: Simplify the initiation of async I/O

Rather than passing a flag around through the entire call stack store it
in the regmap struct and read it when required. This minimises the
visibility of the feature through the API, minimising the code updates
needed to use it more widely.

Signed-off-by: Mark Brown <broonie@linaro.org>

regmap: rbtree: Make cache_present bitmap per node

With devices which have a dense and small register map but placed at a large
offset the global cache_present bitmap imposes a huge memory overhead. Making
the cache_present per rbtree node avoids the issue and easily reduces the memory
footprint by a factor of ten. For devices with a more sparse map or without a
large base register offset the memory usage might increase slightly by a few
bytes, but not significantly. E.g. for a device which has ~50 registers at
offset 0x4000 the memory footprint of the register cache goes down form 2496
bytes to 175 bytes.

Moving the bitmap to a per node basis means that the handling of the bitmap is
now cache implementation specific and can no longer be managed by the core. The
regcache_sync_block() function is extended by a additional parameter so that the
cache implementation can tell the core which registers in the block are set and
which are not. The parameter is optional and if NULL the core assumes that all
registers are set. The rbtree cache also needs to implement its own drop
callback instead of relying on the core to handle this.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

regmap: regcache: allow read-only regs to be cached

The regmap_writeable() check should not be done in
regcache_write() because this prevents read-only
registers to be cached. After a read on a read-only
register its value will not be stored in the cache
and the next time someone will try to read it the
value will be read from the bus instead of the
cache.

Instead the regmap_writeable() check should be done
in _regmap_write() to prevent callers from writing
to read-only registers.

Signed-off-by: Ionut Nicu <ioan.nicu.ext@nsn.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

regmap: cache: Make sure to sync the last register in a block

regcache_sync_block_raw_flush() expects the address of the register after last
register that needs to be synced as its parameter. But the last call to
regcache_sync_block_raw_flush() in regcache_sync_block_raw() passes the address
of the last register in the block. This effectively always skips over the last
register in a block, even if it needs to be synced. In order to fix it increase
the address by one register.

The issue was introduced in commit 75a5f89 ("regmap: cache: Write consecutive
registers in a single block write").

Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

regmap: Implemented default cache sync operation

This can be used for cache types for which syncing values one by one is
equally efficient as syncing a range, such as the flat cache.

Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

regmap: regcache: Fixup locking for custom lock callbacks

The parameter passed to the regmap lock/unlock callbacks needs to be
map->lock_arg, regcache passes just map. This works fine in the case that no
custom locking callbacks are used since in this case map->lock_arg equals map,
but will break when custom locking callbacks are used. The issue was introduced
in commit 0d4529c5("regmap: make lock/unlock functions customizable") and is
fixed by this patch.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: regcache: Fixup locking for custom lock callbacks

The parameter passed to the regmap lock/unlock callbacks needs to be
map->lock_arg, regcache passes just map. This works fine in the case that no
custom locking callbacks are used, since in this case map->lock_arg equals map,
but will break when custom locking callbacks are used. The issue was introduced
in commit 0d4529c5 ("regmap: make lock/unlock functions customizable") and is
fixed by this patch.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Add support for discarding parts of the register cache

Allow drivers to discard parts of the register cache, for example if part
of the hardware has been reset.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: cache: Fix format specifier in dev_dbg

Fix format specifier in dev_dbg and suppress the following warning

drivers/base/regmap/regcache.c: In function
‘regcache_sync_block_raw_flush’:
drivers/base/regmap/regcache.c:593:2: warning: format ‘%d’ expects
argument of type ‘int’, but argument 4 has type ‘size_t’ [-Wformat]

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: cache: Make regcache_sync_block_raw static

regcache_sync_block_raw is used only in this file. Hence make it static.
Silences the following warning:
drivers/base/regmap/regcache.c:608:5: warning:
symbol 'regcache_sync_block_raw' was not declared. Should it be static?

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: cache: Write consecutive registers in a single block write

When syncing blocks of data using raw writes combine the writes into a
single block write, saving us bus overhead for setup, addressing and
teardown.

Currently the block write is done unconditionally as it is expected that
hardware which has a register format which can support raw writes will
support auto incrementing writes, this decision may need to be revised in
future.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>

regmap: cache: Split raw and non-raw syncs

For code clarity after implementing block writes split out the raw and
non-raw I/O sync implementations.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>

regmap: cache: Factor out block sync

The idea of holding blocks of registers in device format is shared between
at least rbtree and lzo cache formats so split out the loop that does the
sync from the rbtree code so optimisations on it can be reused.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>

regmap: cache: Factor out reg_present support from rbtree cache

The idea of maintaining a bitmap of present registers is something that
can usefully be used by other cache types that maintain blocks of cached
registers so move the code out of the rbtree cache and into the generic
regcache code.

Refactor the interface slightly as we go to wrap the set bit and enlarge
bitmap operations (since we never do one without the other) and make it
more robust for reads of uncached registers by bounds checking before we
look at the bitmap.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>

regmap: cache: Provide a get address of value operation

Provide a helper to do the size based index into a block of registers and
use it when reading a value.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: cache: Store caches in native register format where possible

This allows the cached data to be sent directly to the device when
we sync it.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: cache: Use regcache_get_value() to check if we updated

Factor things out a little.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: cache: Pass the map rather than the word size when updating values

It's more idiomatic to pass the map structure around and this means we
can use other bits of information from the map.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: flat: Add flat cache type

While for I2C and SPI devices the overhead of using rbtree for devices with
only one block of registers is negligible the same isn't always going to
be true for MMIO devices where the I/O costs are very much lower. Cater
for these devices by adding a simple flat array type for them where the
lookups are simple array accesses, taking us right back to the original
ASoC cache implementation.

Thanks to Magnus Damm for the discussion which prompted this.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: implement register striding

regmap_config.reg_stride is introduced. All extant register addresses
are a multiple of this value. Users of serial-oriented regmap busses will
typically set this to 1. Users of the MMIO regmap bus will typically set
this based on the value size of their registers, in bytes, so 4 for a
32-bit register.

Throughout the regmap code, actual register addresses are used. Wherever
the register address is used to index some array of values, the address
is divided by the stride to determine the index, or vice-versa. Error-
checking is added to all entry-points for register address data to ensure
that register addresses actually satisfy the specified stride. The MMIO
bus ensures that the specified stride is large enough for the register
size.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: introduce fast_io busses, and use a spinlock for them

Some bus types have very fast IO. For these, acquiring a mutex for every
IO operation is a significant overhead. Allow busses to indicate their IO
is fast, and enhance regmap to use a spinlock for those busses.

[Currently limited to native endian registers -- broonie]

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: implement register striding

regmap_config.reg_stride is introduced. All extant register addresses
are a multiple of this value. Users of serial-oriented regmap busses will
typically set this to 1. Users of the MMIO regmap bus will typically set
this based on the value size of their registers, in bytes, so 4 for a
32-bit register.

Throughout the regmap code, actual register addresses are used. Wherever
the register address is used to index some array of values, the address
is divided by the stride to determine the index, or vice-versa. Error-
checking is added to all entry-points for register address data to ensure
that register addresses actually satisfy the specified stride. The MMIO
bus ensures that the specified stride is large enough for the register
size.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: introduce fast_io busses, and use a spinlock for them

Some bus types have very fast IO. For these, acquiring a mutex for every
IO operation is a significant overhead. Allow busses to indicate their IO
is fast, and enhance regmap to use a spinlock for those busses.

[Currently limited to native endian registers -- broonie]

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Export regcache_sync_region()

regcache_sync_region() isn't going to be useful to most drivers if we
don't export it since otherwise they can't use it when built modular.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

device.h: cleanup users outside of linux/include (C files)

For files that are actively using linux/device.h, make sure
that they call it out. This will allow us to clean up some
of the implicit uses of linux/device.h within include/*
without introducing build regressions.

Yes, this was created by "cheating" -- i.e. the headers were
cleaned up, and then the fallout was found and fixed, and then
the two commits were reordered. This ensures we don't introduce
build regressions into the git history.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

regmap: Allow drivers to sync only part of the register cache

Provide a regcache_sync_region() operation which allows drivers to
write only part of the cache back to the hardware. This is intended
for use in cases like power domains or DSP memories where part of the
device register map may be reset without fully resetting the device.

Fully supporting these devices is likely to require additional work to
make specific regions of the register map cache only while they are in
reset, but this is enough for most devices.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Supply ranges to the sync operations

In order to allow us to support partial sync operations add minimum and
maximum register arguments to the sync operation and update the rbtree
and lzo caches to use this new information. The LZO implementation is
obviously not good, we could exit the iteration earlier, but there may
be room for more wide reaching optimisation there.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Add tracepoints for cache only and cache bypass

Useful for figuring out where the hardware interaction went or came from.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Mark the cache as clean after a successful sync

Previously the cache would never be marked clean, meaning syncs would
never be suppressed which isn't the end of the world but could be
inefficient.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Remove default cache sync implementation

It's not used as all cache types have sync operations so it's just dead
code which never gets tested.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Implement support for 32 bit registers and values

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Bypassing cache when initializing cache

During regcache_init, if client has not passed the
default data of cached register then it is directly
read from the hw to initialize cache. This hw register
read happens before cache ops are initialized and hence
avoiding register read to check for the data available
on cache or not by enabling flag of cache_bypass.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Fix cache defaults initialization from raw cache defaults

Currently registers with a value of 0 are ignored when initializing the register
defaults from raw defaults. This worked in the past, because registers without a
explicit default were assumed to have a default value of 0. This was changed in
commit b03622a8 ("regmap: Ensure rbtree syncs registers set to zero properly").
As a result registers, which have a raw default value of 0 are now assumed to
have no default. This again can result in unnecessary writes when syncing the
cache. It will also result in unnecessary reads for e.g. the first update
operation. In the case where readback is not possible this will even let the
update operation fail, if the register has not been written to before.

So this patch removes the check. Instead it adds a check to ignore raw defaults
for registers which are volatile, since those registers are not cached.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: stable@vger.kernel.org

regmap: Remove incorrect unreachable comment in regcache_set_val()

regcache_set_val() returns false if cache[idx] != val.
Thus it actually is not unreachable.

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Bypass the cache when applying patches

Otherwise any patch that affects a register which is writable may trash
cached values.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Skip patch application when the cache is not dirty on sync

On the basis that if we don't actually need to resync the cache then the
patches are probably also already applied.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Unexport regcache_write() and regcache_read()

They have no current users which is fortunate as they don't take the lock
and therefore aren't safe to use externally. We'll need to add new
operations if direct cache access is needed.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Support register patch sets

Device manufacturers frequently provide register sequences, usually not
fully documented, to be run at startup in order to provide better defaults
for devices (for example, improving performance in the light of silicon
evaluation). Support such updates by allowing drivers to register update
sets with the core. These updates will be written to the device immediately
and will also be rewritten when the cache is synced.

The assumption is that the reason for resyncing the cache will always be
that the device has been powered off. If this turns out to not be the case
then a separate operation can be provided.

Currently the implementation only allows a single set of updates to be
specified for a device, this could be extended in future.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Move initialization of regcache related fields to regcache_init

Move the initialization regcache related fields of the regmap struct to
regcache_init. This allows us to keep regmap and regcache code better
separated.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Add trace event for successful cache reads

Currently we only trace physical reads, there's no instrumentation if
the read is satisfied from cache.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Remove indexed cache type

There should be no situation where it offers any advantage over rbtree
and there are no current users so remove the code for simplicity.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Drop check whether a register is readable in regcache_read

One of the reasons for using a cache is to have a software shadow of a register
which is writable but not readable. This allows us to do a read-modify-write
operation on such a register.

Currently regcache checks whether a register is readable when performing a
cached read and returns an error if it is not. Drop this check, since it will
prevent us from using the cache for registers where read-back is not possible.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Properly round cache_word_size

regcache currently only properly works with val bit sizes of 8 or 16, since
it will, when calculating the cache word size, round down. This causes the
cache storage to be too small to hold the full register value. Fix this by
rounding up instead.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Make reg_config reg_defaults const

The reg_defaults field usually points to a static per driver array, which should
not be modified. Make requirement this explicit by making reg_defaults const.
To allow this the regcache_init code needs some minor changes. Previoulsy the
reg_config was not available in regcache_init and regmap->reg_defaults was used
to pass the default register set to regcache_init. Now that the reg_config is
available we can work on it directly.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Move initialization of regcache related fields to regcache_init

Move the initialization regcache related fields of the regmap struct to
regcache_init. This allows us to keep regmap and regcache code better
separated.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Fix memory leak in regcache_init error path

Make sure all allocated memory gets freed again in case initializing the cache
failed.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Fix memory leak in regcache_hw_init error path

Make sure reg_defaults_raw gets freed in case of an error.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Track if the register cache is dirty and suppress unneeded syncs

Allow drivers to optimise out the register cache sync if they didn't need
to do one. If the hardware is desynced from the register cache (by power
loss for example) then the driver should call regcache_mark_dirty() to
let the core know about this.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base: Add export.h for EXPORT_SYMBOL/THIS_MODULE as required.

Most of these files were implicitly getting EXPORT_SYMBOL via
device.h which was including module.h, but that path will be broken
soon.

[ with input from Stephen Rothwell <sfr@canb.auug.org.au> ]

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

regmap: Allow caches for devices with no defaults

We only really need the defaults in order to cut down the number of
registers we sync and to satisfy reads while the device is powered off
but not all devices are going to need to do that (always on devices like
PMICs being the prime example) so don't require those devices to supply
a default. Instead only try to fall back to hardware defaults if the
driver told us to.

Devices using LZO won't be able to instantiate with this, that will require
some updates in the LZO code to handle this case.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>

regmap: Return a sensible error code if we fail to read the cache

If a register isn't cached then let callers know that so they can fall
back or error handle appropriately.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>

regmap: Use bsearch() to search the register defaults

Rather than open coding a binary search use the standard bsearch() using
the comparison function we're already using for sort() on insert. This
fixes a lockup I was observing due to iterating on min <= max rather
than min < max when we fail to look up.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>

regmap: Fix doc comment

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Optimize the lookup path to use binary search

Since there are more lookups than insertions in a typical
scenario, optimize the linear search into a binary search. For
this to work, we need to keep reg_defaults sorted upon
insertions, for now be lazy and use sort().

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Ensure we scream if we enable cache bypass/only at the same time

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Implement regcache_cache_bypass helper function

Ensure we've got a function so users can enable/disable the
cache bypass option.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Save/restore the bypass state upon syncing

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Lock the sync path, ensure we use the lockless _regmap_write()

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Fix apostrophe usage

An apostrophe does not mean "look out, here comes an s!".

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Fix lock used for regcache_cache_only()

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Grab the lock in regcache_cache_only()

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Modify map->cache_bypass directly

In preperation for the upcoming patches, modify map->cache_bypass
directly. The helper functions will grab an exclusive lock. Because
we'll have acquired the same lock we need to avoid a deadlock.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Fix regcache_sync generic implementation

We want to use regmap_write() to actually write anything
to the HW.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Implement generic syncing functionality

In the absence of a sync callback, do it manually. This of course
can't take advantange of the specific optimizations of each
cache type but it will do well enough in most cases.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Allow drivers to control cache_only flag

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: A cache type of _NONE behaves like a bypassed cache

Avoid extra special casing by setting the cache_bypass flag when we're
not caching.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Add the regcache_sync trace event

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Add the LZO cache support

This patch adds support for LZO compression when storing the register
cache.

For a typical device whose register map would normally occupy 25kB or 50kB
by using the LZO compression technique, one can get down to ~5-7kB. There
might be a performance penalty associated with each individual read/write
due to decompressing/compressing the underlying cache, however that should not
be noticeable. These memory benefits depend on whether the target architecture
can get rid of the memory occupied by the original register defaults cache
which is marked as __devinitconst. Nevertheless there will be some memory
gain even if the target architecture can't get rid of the original register
map, this should be around ~30-32kB instead of 50kB.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Add the rbtree cache support

This patch adds support for the rbtree cache compression type.

Each rbnode manages a variable length block of registers. There can be no
two nodes with overlapping blocks. Each block has a base register and a
currently top register, all the other registers, if any, lie in between these
two and in ascending order.

The reasoning behind the construction of this rbtree is simple. In the
snd_soc_rbtree_cache_init() function, we iterate over the register defaults
provided by the regcache core. For each register value that is non-zero we
insert it in the rbtree. In order to determine in which rbnode we need
to add the register, we first look if there is another register already
added that is adjacent to the one we are about to add. If that is the case
we append it in that rbnode block, otherwise we create a new rbnode
with a single register in its block and add it to the tree.

There are various optimizations across the implementation to speed up lookups
by caching the most recently used rbnode.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Add the indexed cache support

This is the simplest form of a cache available in regcache. Any
registers whose default value is 0 are ignored. If any of those
registers are modified in the future, they will be placed in the
cache on demand. The cache layout is essentially using the provided
register defaults by the regcache core directly and does not re-map
it to another representation.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

regmap: Introduce caching support

This patch introduces caching support for regmap. The regcache API
has evolved essentially out of ASoC soc-cache so most of the actual
caching types (except LZO) have been tested in the past.

The purpose of regcache is to optimize in time and space the handling
of register caches. Time optimization is achieved by not having to go
over a slow bus like I2C to read the value of a register, instead it is
cached locally in memory and can be retrieved faster. Regarding space
optimization, some of the cache types are better at packing the caches,
for e.g. the rbtree and the LZO caches. By doing this the sacrifice in
time still wins over doing I2C transactions.

Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>