rtc: sun6i: remove unnecessary message

The core already print a message once the rtc is successfully registered,
it is not necessary to print an other one.

Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20230827221643.544259-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: 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>
Link: https://lore.kernel.org/r/20230724205456.767430-1-robh@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Add a determine_rate hook

The Allwinner sun6i RTC clock implements a mux with a set_parent hook,
but doesn't provide a determine_rate implementation.

This is a bit odd, since set_parent() is there to, as its name implies,
change the parent of a clock. However, the most likely candidates to
trigger that parent change are either the assigned-clock-parents device
tree property or a call to clk_set_rate(), with determine_rate()
figuring out which parent is the best suited for a given rate.

The other trigger would be a call to clk_set_parent(), but it's far less
used, and it doesn't look like there's any obvious user for that clock.

Similarly, it doesn't look like the device tree using that clock driver
uses any of the assigned-clock properties on that clock.

So, the set_parent hook is effectively unused, possibly because of an
oversight. However, it could also be an explicit decision by the
original author to avoid any reparenting but through an explicit call to
clk_set_parent().

The latter case would be equivalent to setting the determine_rate
implementation to clk_hw_determine_rate_no_reparent(). Indeed, if no
determine_rate implementation is provided, clk_round_rate() (through
clk_core_round_rate_nolock()) will call itself on the parent if
CLK_SET_RATE_PARENT is set, and will not change the clock rate
otherwise.

And if it was an oversight, then we are at least explicit about our
behavior now and it can be further refined down the line.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Jernej Skrabec <jernej.skrabec@gmail.com>
Cc: Samuel Holland <samuel@sholland.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-rtc@vger.kernel.org
Cc: linux-sunxi@lists.linux.dev
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20221018-clk-range-checks-fixes-v4-45-971d5077e7d2@cerno.tech
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

rtc: sun6i: Use of_property_present() for testing DT property presence

It is preferred to use typed property access functions (i.e.
of_property_read_<type> functions) rather than low-level
of_get_property/of_find_property functions for reading properties. As
part of this, convert of_get_property/of_find_property calls to the
recently added of_property_present() helper when we just want to test
for presence of a property and nothing more.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Link: https://lore.kernel.org/r/20230310144736.1547041-1-robh@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Always export the internal oscillator

On all variants of the hardware, the internal oscillator is one possible
parent for the AR100 clock. It needs to be exported so we can model that
relationship correctly in the devicetree.

Fixes: c56afc1844d6 ("rtc: sun6i: Expose internal oscillator through device tree")
Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20221229215319.14145-1-samuel@sholland.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: add support for R329 RTC

Allwinner R329 has a RTC with a similar time storage with H616 but a
slightly different clock part.

As we have already handled the R329 RTC clocks in the CCU driver, add a
compatible string to RTC driver to allow probing of the RTC.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220626042756.58961-1-samuel@sholland.org

rtc: sun6i: Add NVMEM provider

The sun6i RTC provides 32 bytes of general-purpose data registers.
They can be used to save data in the always-on RTC power domain.
The registers are writable via 32-bit MMIO accesses only.

Expose them with a NVMEM provider so they can be used by other drivers.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220413231731.56709-1-samuel@sholland.org

Revert "clk: sunxi-ng: sun6i-rtc: Add support for H6"

This reverts commit 1738890a3165ccd0da98ebd3e2d5f9b230d5afa8.

Commit 1738890a3165 ("clk: sunxi-ng: sun6i-rtc: Add support for H6")
breaks HDMI output on Tanix TX6 mini board. Exact reason isn't known,
but because that commit doesn't actually improve anything, let's just
revert it.

Cc: stable@vger.kernel.org
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Link: https://lore.kernel.org/r/20220511200206.2458274-1-jernej.skrabec@gmail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

clk: sunxi-ng: sun6i-rtc: Add support for H6

H6 supports IOSC calibration and an ext-osc32k input. Unlike newer SoCs,
it has a single parent for its fanout clock.

Add support for H6 in the CCU driver, replacing the support in the
existing early OF clock provider.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220203021736.13434-7-samuel@sholland.org

clk: sunxi-ng: Add support for the sun6i RTC clocks

The RTC power domain in sun6i and newer SoCs manages the 16 MHz RC
oscillator (called "IOSC" or "osc16M") and the optional 32 kHz crystal
oscillator (called "LOSC" or "osc32k"). Starting with the H6, this power
domain also handles the 24 MHz DCXO (called variously "HOSC", "dcxo24M",
or "osc24M") as well. The H6 also adds a calibration circuit for IOSC.

Later SoCs introduce further variations on the design:
- H616 adds an additional mux for the 32 kHz fanout source.
- R329 adds an additional mux for the RTC timekeeping clock, a clock
for the SPI bus between power domains inside the RTC, and removes the
IOSC calibration functionality.

Take advantage of the CCU framework to handle this increased complexity.
This driver is intended to be a drop-in replacement for the existing RTC
clock provider. So some runtime adjustment of the clock parents is
needed, both to handle hardware differences, and to support the old
binding which omitted some of the input clocks.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220203021736.13434-6-samuel@sholland.org

rtc: sun6i: Add Allwinner H616 support

The H616 RTC changes its day storage to the newly introduced linear day
scheme, so pair the new compatible string with this feature flag.
The RTC clock parts are handled in a separate driver now, so we skip
the clock parts in this driver completely.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220211122643.1343315-7-andre.przywara@arm.com

rtc: sun6i: Add support for broken-down alarm registers

Newer versions of the Allwinner RTC, for instance as found in the H616
SoC, not only store the current day as a linear number, but also change
the way the alarm is handled: There are now two registers, that
explicitly store the wakeup time, in the same format as the current
time.

Add support for that variant by writing the requested wakeup time
directly into the registers, instead of programming the seconds left, as
the old SoCs required.

Reviewed by: Jernej Skrabec <jernej.skrabec@gmail.com>

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220211122643.1343315-6-andre.przywara@arm.com

rtc: sun6i: Add support for linear day storage

Newer versions of the Allwinner RTC, as for instance found in the H616
SoC, no longer store a broken-down day/month/year representation in the
RTC_DAY_REG, but just a linear day number.
The user manual does not give any indication about the expected epoch
time of this day count, but the BSP kernel uses the UNIX epoch, which
allows easy support due to existing conversion functions in the kernel.

Allow tagging a compatible string with a flag, and use that to mark
those new RTCs. Then convert between a UNIX day number (converted into
seconds) and the broken-down day representation using mktime64() and
time64_to_tm() in the set_time/get_time functions.

That enables support for the RTC in those new chips.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220211122643.1343315-5-andre.przywara@arm.com

rtc: sun6i: Fix time overflow handling

Using "unsigned long" for UNIX timestamps is never a good idea, and
comparing the value of such a variable against U32_MAX does not do
anything useful on 32-bit systems.

Use the proper time64_t type when dealing with timestamps, and avoid
cutting down the time range unnecessarily. This also fixes the flawed
check for the alarm time being too far into the future.

The check for this condition is actually somewhat theoretical, as the
RTC counts till 2033 only anyways, and 2^32 seconds from now is not
before the year 2157 - at which point I hope nobody will be using this
hardware anymore.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220211122643.1343315-4-andre.przywara@arm.com

rtc: sun6i: Enable the bus clock when provided

H6 and newer variants of the RTC hardware have a bus clock gate in the
PRCM CCU. This was not known at the time H6 support was added, so it was
not included in the H6 RTC binding, nor in the H6 PRCM CCU driver. Now
that this clock gate is documented, it is included in the A100 and D1
PRCM CCU drivers. Therefore, the RTC driver needs to have a consumer for
the clock gate to prevent Linux from disabling it.

Patch-changes: 3
- New patch for compatibility with new CCU drivers

Signed-off-by: Samuel Holland <samuel@sholland.org>
Reviewed-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220203021736.13434-4-samuel@sholland.org

rtc: sun6i: Allow probing without an early clock provider

Some SoCs have an RTC supported by this RTC driver, but do not have an
early clock provider declared here. Currently, this prevents the RTC
driver from probing, because it expects a global struct to already be
allocated. Fix probing the driver by copying the missing pieces from the
clock provider setup function, replacing them with the devm variants.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210928080335.36706-7-samuel@sholland.org

rtc: rework rtc_register_device() resource management

rtc_register_device() is a managed interface but it doesn't use devres
by itself - instead it marks an rtc_device as "registered" and the devres
callback for devm_rtc_allocate_device() takes care of resource release.

This doesn't correspond with the design behind devres where managed
structures should not be aware of being managed. The correct solution
here is to register a separate devres callback for unregistering the
device.

While at it: rename rtc_register_device() to devm_rtc_register_device()
and add it to the list of managed interfaces in devres.rst. This way we
can avoid any potential confusion of driver developers who may expect
there to exist a corresponding unregister function.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201109163409.24301-8-brgl@bgdev.pl

rtc: sun6i: Fix memleak in sun6i_rtc_clk_init

When clk_hw_register_fixed_rate_with_accuracy() fails,
clk_data should be freed. It's the same for the subsequent
two error paths, but we should also unregister the already
registered clocks in them.

Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201020061226.6572-1-dinghao.liu@zju.edu.cn

rtc: sun6i: let the core handle rtc range

Let the rtc core check the date/time against the RTC range.

Tested-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Link: https://lore.kernel.org/r/20200330201226.860967-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: switch to rtc_time64_to_tm/rtc_tm_to_time64

Call the 64bit versions of rtc_tm time conversion.

Tested-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Link: https://lore.kernel.org/r/20200330201226.860967-2-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Make external 32k oscillator optional

Some boards, like OrangePi PC2 (H5), OrangePi Plus 2E (H3) and Tanix TX6
(H6) don't have external 32kHz oscillator. Till H6, it didn't really
matter if external oscillator was enabled because HW detected error and
fall back to internal one. H6 has same functionality but it's the first
SoC which have "auto switch bypass" bit documented and always enabled in
driver. This prevents RTC to work correctly if external crystal is not
present on board. There are other side effects - all peripherals which
depends on this clock also don't work (HDMI CEC for example).

Make clocks property optional. If it is present, select external
oscillator. If not, stay on internal.

Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20200308135849.106333-2-jernej.skrabec@siol.net
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Add support for RTC clocks on R40

When support for the R40 in the rtc-sun6i driver was split out for a
separate compatible string, only the RTC half was covered, and not the
clock half. Unfortunately this results in the whole driver not working,
as the RTC half expects the clock half to have been initialized.

Add support for the clock part as well. The clock part is like the H3,
but does not need to export the internal oscillator, nor does it have
a gateable LOSC external output.

This fixes issues with WiFi and Bluetooth not working on the BPI M2U.

Fixes: d6624cc75021 ("rtc: sun6i: Add R40 compatible")
Cc: <stable@vger.kernel.org> # 5.3.x
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20191205085054.6049-1-wens@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Remove struct device from sun6i_rtc_dev

struct device in struct sun6i_rtc_dev is not used, remove it.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Link: https://lore.kernel.org/r/20191123090538.32364-1-nobuhiro1.iwamatsu@toshiba.co.jp
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Allow using as wakeup source from suspend

This patch allows userspace to set up wakeup alarms on any RTC handled by the
sun6i driver, and adds the necessary PM operations to allow resuming from
suspend when the configured wakeup alarm fires a IRQ. Of course, that the
device actually resumes depends on the suspend state and how a particular
hardware reacts to it, but that is out of scope for this patch.

I've tested these changes on a Pine H64 model B, which contains a
Allwinner H6 SoC, with the help of CONFIG_PM_TEST_SUSPEND kernel option.
These are the interesting outputs from the kernel and commands which
show that it works. As every RTC handled by this driver is largely the
same, I think that it shouldn't introduce any regression on other SoCs,
but I may be wrong.

[ 1.092705] PM: test RTC wakeup from 'freeze' suspend
[ 1.098230] PM: suspend entry (s2idle)
[ 1.212907] PM: suspend devices took 0.080 seconds
(The SoC freezes for some seconds)
[ 3.197604] PM: resume devices took 0.104 seconds
[ 3.215937] PM: suspend exit

[ 1.092812] PM: test RTC wakeup from 'mem' suspend
[ 1.098089] PM: suspend entry (deep)
[ 1.102033] PM: suspend exit
[ 1.105205] PM: suspend test failed, error -22

In any case, the RTC alarm interrupt gets fired as exptected:

$ echo +5 > /sys/class/rtc/rtc0/wakealarm && sleep 5 && grep rtc /proc/interrupts
29: 1 0 0 0 GICv2 133 Level 7000000.rtc

Signed-off-by: Alejandro González <alejandro.gonzalez.correo@gmail.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20190821210056.11995-1-alejandro.gonzalez.correo@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Add support for H6 RTC

RTC on H6 is mostly the same as on H5 and H3. It has slight differences
mostly in features that are not yet supported by this driver.

Some differences are already stated in the comments in existing code.
One other difference is that H6 has extra bit in LOSC_CTRL_REG, called
EXT_LOSC_EN to enable/disable external low speed crystal oscillator.

It also has bit EXT_LOSC_STA in LOSC_AUTO_SWT_STA_REG, to check whether
external low speed oscillator is working correctly.

This patch adds support for enabling LOSC when necessary:

- during reparenting
- when probing the clock

H6 also has capacbility to automatically reparent RTC clock from
external crystal oscillator, to internal RC oscillator, if external
oscillator fails. This is enabled by default. Disable it during
probe.

Signed-off-by: Ondrej Jirman <megous@megous.com>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Link: https://lore.kernel.org/r/20190820151934.3860-3-megous@megous.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Don't reference clk_init_data after registration

A future patch is going to change semantics of clk_register() so that
clk_hw::init is guaranteed to be NULL after a clk is registered. Avoid
referencing this member here so that we don't run into NULL pointer
exceptions.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lkml.kernel.org/r/20190815160020.183334-4-sboyd@kernel.org
Acked-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: Remove dev_err() usage after platform_get_irq()

We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.

// <smpl>
@@
expression ret;
struct platform_device *E;
@@

ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);

if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>

While we're here, remove braces on if statements that only have one
statement (manually).

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: linux-rtc@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-40-swboyd@chromium.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Add R40 compatible

The R40 has a quite different RTC, with only a single interrupt line, but
two clock outputs. Let's add a compatible.

Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157

Based on 3 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [kishon] [vijay] [abraham]
[i] [kishon]@[ti] [com] this program is distributed in the hope that
it will be useful but without any warranty without even the implied
warranty of merchantability or fitness for a particular purpose see
the gnu general public license for more details

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version [author] [graeme] [gregory]
[gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
[kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
[hk] [hemahk]@[ti] [com] this program is distributed in the hope
that it will be useful but without any warranty without even the
implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

rtc: sun6i: Expose internal oscillator through device tree

The bindings have been updated to expose the RTC's internal oscillator,
for some SoCs that have it directly feeding the PRCM block. The changes
include the index 2 for the clock outputs, as well as the clock output
names.

This patch adds the internal oscillator to the list of clocks exposed
through of_clk_add_hw_provider(), and also have the driver optionally
fetch the name of the clock from the device tree if it's available.

Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Add support for all known pre-H6 variants

There are different variants to the RTC hardware first seen on sun6i
(A31). The differences we care about in this driver are the clock rate
for the internal oscillator, prescalers, and the presence of an external
clock output.

This patch adds support for all the known pre-H6 base compatibles using
the variants data structure previously introduced.

Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Add support for different variants

Amongst the Allwinner SoCs that have seen some kind of coverage by the
linux-sunxi community, whether it be mainline Linux or U-boot support,
or just available datasheets, most newer chips use the RTC design first
seen in the A31 (sun6i).

Overall there have been some minor differences. This patch covers the
following:

- average clock rate of the internal RC oscillator
+ presence of fixed and adjustable prescaler for this clock
- availability of an external (to the SoC) clock output

One major difference regarding the H6 is the 24 MHz crystal is now
routed through the RTC, as a digitally compensated oscillator (DCXO).
This is not covered in this patch and will be supported later.

Other differences are either unrelated to RTC or clock functionality,
such as boot or crypto related registers, or the driver simply doesn't
use the feature in question. One example of the latter is the
calibration function for the RC oscillator. We consider this clock to
be very bad and avoid using it.

Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Add default clock name for LOSC

The RTC's main clock, used internally and exported to the rest of the
SoC, is called "LOSC" (low speed oscillator) through the hardware
documentation.

This patch adds a default name for this clock, in case the device tree
does not provide one. This shouldn't happen, but lets play it safe.

Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Tested-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Use struct_size() in kzalloc()

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:

struct foo {
int stuff;
void *entry[];
};

instance = kzalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: Fix bit_idx value for clk_register_gate

clk-gate core will take bit_idx through clk_register_gate
and then do clk_gate_ops by using BIT(bit_idx), but rtc-sun6i
is passing bit_idx as BIT(bit_idx) it becomes BIT(BIT(bit_idx)
which is wrong and eventually external gate clock is not enabling.

This patch fixed by passing bit index and the original change
introduced from below commit.
"rtc: sun6i: Add support for the external oscillator gate"
(sha1: 17ecd246414b3a0fe0cb248c86977a8bda465b7b)

Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>
Fixes: 17ecd246414b ("rtc: sun6i: Add support for the external oscillator gate")
Cc: stable@vger.kernel.org
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: stop validating rtc_time in .read_time

The RTC core is always calling rtc_valid_tm after the read_time callback.
It is not necessary to call it just before returning from the callback.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: sun6i: ensure rtc is kfree'd on error

The error return path on clk_data allocation failure does not kfree
the allocated rtc object. Fix this with a kfree of rtc on the error
exit path.

Detected by CoverityScan, CID#1452264 ("Resource Leak")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: Add support for the external oscillator gate

The RTC can output its 32kHz clock outside of the SoC, for example to clock
a WiFi chip.

Create a new clock that other devices will be able to retrieve, while
maintaining the DT stability by providing a default name for that clock if
clock-output-names doesn't list one.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: ensure clk_data is kfree'd on error

There are two error return paths that do not kfree clk_data and
we end up with a memory leak. Fix these with a kfree error exit
path.

Detected by CoverityScan, CID#1402959 ("Resource Leak")

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: Remove double init of spinlock in sun6i_rtc_clk_init()

Remove double init of spinlock in sun6i_rtc_clk_init()

Fixes: 847b8bf62eb4 ("rtc: sun6i: Expose the 32kHz oscillator")
Signed-off-by: Alexey Klimov <alexey.klimov@arm.com>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: Fix return value check in sun6i_rtc_clk_init()

In case of error, the function of_io_request_and_map() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check should
be replaced with IS_ERR().

Fixes: 847b8bf62eb4 ("rtc: sun6i: Expose the 32kHz oscillator")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: Fix compatibility with old DT binding

Commit 847b8bf62eb4 ("rtc: sun6i: Expose the 32kHz oscillator") adds
a new clock for the rtc block with a 2 step probe mechanism. To share
the register region between both the clock and rtc instance, a static
pointer is used to keep the related data structure.

To preserve compatibility with the old binding, the data structure
should be saved as soon as the registers are mapped in, regardless
of the presence of the clock bindings, so that the rtc device can
retrieve it when it is probed.

This fixes the rtc device not probing when we use the updated driver
with an old device tree blob.

Fixes: 847b8bf62eb4 ("rtc: sun6i: Expose the 32kHz oscillator")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: Switch to devm_rtc_device_register

Now that we have a devm variant of rtc_device_register, switch to it.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: Expose the 32kHz oscillator

The RTC controls the input source of the main 32kHz oscillator in the
system, feeding it to the clock unit too.

By default, this is using an internal, very inaccurate (+/- 30%)
oscillator with a divider to make it roughly around 32kHz. This is however
quite impractical for the RTC, since our time will not be tracked properly.

Since this oscillator is an input of the main clock unit, and since that
clock unit will be probed using CLK_OF_DECLARE, we have to use it as well,
leading to a two stage probe: one to enable the clock, the other one to
enable the RTC.

There is also a slight change in the binding that is required (and should
have been from the beginning), since we'll need a phandle to the external
oscillator used on that board. We support the old binding by not allowing
to switch to the external oscillator and only using the internal one (which
was the previous behaviour) in the case where we're missing that phandle.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: Switch to the external oscillator

The RTC is clocked from either an internal, imprecise, oscillator or an
external one, which is usually much more accurate.

The difference perceived between the time elapsed and the time reported by
the RTC is in a 10% scale, which prevents the RTC from being useful at all.

Fortunately, the external oscillator is reported to be mandatory in the
Allwinner datasheet, so we can just switch to it.

Cc: stable@vger.kernel.org
Fixes: 9765d2d94309 ("rtc: sun6i: Add sun6i RTC driver")
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: Add some locking

Some registers have a read-modify-write access pattern that are not atomic.

Add some locking to prevent from concurrent accesses.

Cc: stable@vger.kernel.org
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: Disable the build as a module

Since we have to provide the clock very early on, the RTC driver cannot be
built as a module. Make sure that won't happen.

Cc: stable@vger.kernel.org
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: sun6i: Add sun6i RTC driver

This patch introduces the driver for the RTC in the Allwinner A31 and
A23 SoCs.

Unlike the RTC found in A10/A20 SoCs, which was part of the timer, the
RTC in A31/A23 are a separate hardware block, which also contain a few
controls for the RTC block hardware (a regulator and RTC block GPIO pin
latches), while also having separate interrupts for the alarms.

The hardware is different enough to make a different driver for it.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Varka Bhadram <varkabhadram@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>