This drivers allows to communicate with a RTC PTA handled by OP-TEE [1].
This PTA allows to query RTC information, set/get time and set/get
offset depending on the supported features.
[1] https://github.com/OP-TEE/optee_os/pull/5179
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220308133505.471601-1-clement.leger@bootlin.com
Having !allow_set_time is equivalent to non-implemented set_time
function, which is normally represented with -ENODEV error in RTC
subsystem.
Today we are returning -EACCES error code, which is not considered
by RTC clients as a 'non implemented' feature, and which causes NTP
to retry hw clk sync (update_rtc) indefinitely.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1645090578-20734-1-git-send-email-loic.poulain@linaro.org
Attach the interrupt as a wake-irq to the device, so that:
- A corresponding wakeup source is created (and reported in e.g
/sys/kernel/debug/wakeup_sources).
- The power subsystem take cares of arming/disarming
irq-wake automatically on suspend/resume.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1645025082-6138-1-git-send-email-loic.poulain@linaro.org
Stop using uie_unsupported and clear RTC_FEATURE_UPDATE_INTERRUPT instead.
Also the driver doesn't supports UIE because it doesn't handle interrupts
so set RTC_FEATURE_ALARM_WAKEUP_ONLY,.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220309162301.61679-24-alexandre.belloni@bootlin.com
The reference manual doesn't specify whether the registers are latched and
they probably aren't, ensure the read time and date are consistent.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20220309162301.61679-21-alexandre.belloni@bootlin.com
Since commitc9f5c7e7a84f ("rtc: rtc-spear: Provide flag for no support of
UIE mode") which was in 2012, the core changed a lot and UIE are now
supported using regular alarms. Drop uie_unsupported now to reflect that.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20220309162301.61679-20-alexandre.belloni@bootlin.com
While the RTC can store dates from year 0000 to 9999, leap years where not
tested fro 2100. The driver currently stores tm_year directly which will
probably fail at that time or more probably in 2300.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20220309162301.61679-19-alexandre.belloni@bootlin.com
No platforms are currently setting no_irq. Anyway, letting platform_get_irq
fail is fine as this means that there is no IRQ. In that case, clear
RTC_FEATURE_ALARM so the core knows there are no alarms.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220309162301.61679-2-alexandre.belloni@bootlin.com
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
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
As the potential failure of the wm8350_register_irq(),
it should be better to check it and return error if fails.
Also, it need not free 'wm_rtc->rtc' since it will be freed
automatically.
Fixes: 077eaf5b40 ("rtc: rtc-wm8350: add support for WM8350 RTC")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220303085030.291793-1-jiasheng@iscas.ac.cn
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
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
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
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
When there is no interrupt line, rtc alarm feature is disabled.
The clearing of the alarm feature bit was being done prior to allocations
of ldata->rtc device, resulting in a null pointer dereference.
Clear RTC_FEATURE_ALARM after the rtc device is allocated.
Fixes: d9b0dd54a1 ("rtc: pl031: use RTC_FEATURE_ALARM")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Pouladi <quic_apouladi@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220225161924.274141-1-quic_eberman@quicinc.com
In mc146818_set_time(), CMOS_READ(RTC_CONTROL) was performed without the
rtc_lock taken, which is required for CMOS accesses. Fix this.
Nothing in kernel modifies RTC_DM_BINARY, so a separate critical section
is allowed here.
Fixes: dcf257e926 ("rtc: mc146818: Reduce spinlock section in mc146818_set_time()")
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220220090403.153928-1-mat.jonczyk@o2.pl
The RTC included in the MAX77714 PMIC is very similar to the one in the
MAX77686. Reuse the rtc-max77686.c driver with the minimum required changes
for the MAX77714 RTC.
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The MAX77714 RTC chip is explicitly set to 24-hour mode in
max77686_rtc_probe() -> max77686_rtc_init_reg() and never changed back to
12-hour mode. Accordingly info->rtc_24hr_mode is set to 1 in the same place
and never modified later, so it is de facto a constant. Yet there is code
to read 12-hour time, which is unreachable.
Remove the unused variable, the unreachable code to manage 12-hour mode and
the defines that become unused due to the above changes.
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
RTC_DATE and REG_RTC_DATE are used for the registers holding the day of
month. Rename these constants to mean what they mean.
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Convert the comments documenting this struct to kernel-doc format for
standardization and readability.
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
The first bug is that reading the 5 alarm registers results in a read
operation of 20 bytes. The reason is because the destination buffer is
defined as an array of "unsigned int", and we use the sizeof()
operator on this array to define the bulk read count.
The second bug is that the read value is invalid, because we are
indexing the destination buffer as integers (4 bytes), instead of
indexing it as u8.
Changing the destination buffer type to u8 fixes both problems.
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220208162908.3182581-1-hugo@hugovil.com
If the interrupt pin of the PCF2127 is routed to the input of a GPIO
expander using the pca953x driver, the later will only accept an IRQ
of type IRQ_TYPE_EDGE_FALLING or IRQ_TYPE_EDGE_RISING, and the IRQ
request will fail.
Therefore, allow the IRQ type to be passed from the device tree data
if available.
Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220117225742.1252362-1-hugo@hugovil.com
When building with automatic stack variable initialization, GCC 12
complains about variables defined outside of switch case statements.
Move variables outside the switch, which silences warnings:
./drivers/rtc/rtc-pcf8523.c:284:20: error: statement will never be executed [-Werror=switch-unreachable]
284 | u8 mode;
|
./drivers/rtc/rtc-pcf8523.c:245:21: error: statement will never be executed [-Werror=switch-unreachable]
245 | u32 value;
| ^~~~~
Signed-off-by: Victor Erminpour <victor.erminpour@oracle.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/1644453027-886-1-git-send-email-victor.erminpour@oracle.com
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
If the irqwork is still scheduled or running while the RTC device is
removed, a use-after-free occurs in rtc_timer_do_work(). Cleanup the
timerqueue and ensure the work is stopped to fix this.
BUG: KASAN: use-after-free in mutex_lock+0x94/0x110
Write of size 8 at addr ffffff801d846338 by task kworker/3:1/41
Workqueue: events rtc_timer_do_work
Call trace:
mutex_lock+0x94/0x110
rtc_timer_do_work+0xec/0x630
process_one_work+0x5fc/0x1344
...
Allocated by task 551:
kmem_cache_alloc_trace+0x384/0x6e0
devm_rtc_allocate_device+0xf0/0x574
devm_rtc_device_register+0x2c/0x12c
...
Freed by task 572:
kfree+0x114/0x4d0
rtc_device_release+0x64/0x80
device_release+0x8c/0x1f4
kobject_put+0x1c4/0x4b0
put_device+0x20/0x30
devm_rtc_release_device+0x1c/0x30
devm_action_release+0x54/0x90
release_nodes+0x124/0x310
devres_release_group+0x170/0x240
i2c_device_remove+0xd8/0x314
...
Last potentially related work creation:
insert_work+0x5c/0x330
queue_work_on+0xcc/0x154
rtc_set_time+0x188/0x5bc
rtc_dev_ioctl+0x2ac/0xbd0
...
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210160951.7718-1-vincent.whitchurch@axis.com
The value returned by an spi driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)
So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Claudius Heine <ch@denx.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220123175201.34839-6-u.kleine-koenig@pengutronix.de
Signed-off-by: Mark Brown <broonie@kernel.org>
If devm_ioremap_resource() fails, it should return error
code from sp_rtc->reg_base in sp_rtc_probe().
Fixes: fad6cbe9b2 ("rtc: Add driver for RTC in Sunplus SP7021")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220106075711.3216468-1-yangyingliang@huawei.com
There's limiting the year to 2069. When setting the rtc year to 2070,
reading it returns 1970. Evaluate century starting from 19 to count the
correct year.
$ sudo date -s 20700106
Mon 06 Jan 2070 12:00:00 AM CST
$ sudo hwclock -w
$ sudo hwclock -r
1970-01-06 12:00:49.604968+08:00
Fixes: 2a4daadd4d ("rtc: cmos: ignore bogus century byte")
Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
Acked-by: Eric Wong <e@80x24.org>
Reviewed-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220106084609.1223688-1-luriwen@kylinos.cn
The devm_kzalloc() function returns NULL on error, it doesn't return
error pointers.
Fixes: 86559400b3 ("rtc: gamecube: Add a RTC driver for the GameCube, Wii and Wii U")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220107073340.GF22086@kili
The mc146818_get_time() function returns zero on success or negative
a error code on failure. It needs to be type int.
Fixes: d35786b3a2 ("rtc: mc146818-lib: change return values of mc146818_get_time()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220111071922.GE11243@kili
With the latest stable kernel versions the rtc on the PXA based
Zaurus does not work, when booting I see the following kernel messages:
pxa-rtc pxa-rtc: failed to find rtc clock source
pxa-rtc pxa-rtc: Unable to init SA1100 RTC sub-device
pxa-rtc: probe of pxa-rtc failed with error -2
hctosys: unable to open rtc device (rtc0)
I think this is because commit f2997775b1 ("rtc: sa1100: fix possible
race condition") moved the allocation of the rtc_device struct out of
sa1100_rtc_init and into sa1100_rtc_probe. This means that pxa_rtc_probe
also needs to do allocation for the rtc_device struct, otherwise
sa1100_rtc_init will try to dereference a null pointer. This patch adds
that allocation by copying how sa1100_rtc_probe in
drivers/rtc/rtc-sa1100.c does it; after the IRQs are set up a managed
rtc_device is allocated.
I've tested this patch with `qemu-system-arm -machine akita` and with a
real Zaurus SL-C1000 applied to 4.19, 5.4, and 5.10.
Signed-off-by: Laurence de Bruxelles <lfdebrux@gmail.com>
Fixes: f2997775b1 ("rtc: sa1100: fix possible race condition")
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220101154149.12026-1-lfdebrux@gmail.com
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211220011524.17206-1-prabhakar.mahadev-lad.rj@bp.renesas.com
When building with automatic stack variable initialization, GCC 12
complains about variables defined outside of switch case statements.
Move the variable into the case that uses it, which silences the warning:
drivers/rtc/dev.c: In function 'rtc_dev_ioctl':
drivers/rtc/dev.c:394:30: warning: statement will never be executed [-Wswitch-unreachable]
394 | long offset;
| ^~~~~~
Fixes: 6a8af1b656 ("rtc: add parameter ioctl")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211209043915.1378393-1-keescook@chromium.org
The XSL bit only exists in RS5C372A/B. On other Ricoh RTC chips
supported in rs5c372, this bit has different meaning. For example, on
R2221x and R2223x, this bit of oscillation adjustment register
determines the operation frequency of oscillation adjustment circuit and
the oscillation is always 32768HZ. But rs5c372_get_trim gives 32000HZ to
osc when DEV is 1.
Signed-off-by: Camel Guo <camelg@axis.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211206125832.6461-1-camel.guo@axis.com
In order for linux userspace application to be able to adjust offset to
keep rtc precision as high as possible, this commit adds support of
offset correction by adjusting the time trimming register on
rs5c372[a|b] and oscilluation adjustment register on r2025x, r222[1|3]x,
rv5c38[6|7]a.
Signed-off-by: Camel Guo <camelg@axis.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211202152252.31264-1-camel.guo@axis.com
Some Intel chipsets disconnect the time and date RTC registers when the
clock update is in progress: during this time reads may return bogus
values and writes fail silently. This includes the RTC alarm registers.
[1]
cmos_set_alarm() did not take account for that, fix it.
[1] 7th Generation Intel ® Processor Family I/O for U/Y Platforms [...]
Datasheet, Volume 1 of 2 (Intel's Document Number: 334658-006)
Page 208
https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/7th-and-8th-gen-core-family-mobile-u-y-processor-lines-i-o-datasheet-vol-1.pdf
"If a RAM read from the ten time and date bytes is attempted
during an update cycle, the value read do not necessarily
represent the true contents of those locations. Any RAM writes
under the same conditions are ignored."
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210200131.153887-10-mat.jonczyk@o2.pl
Some Intel chipsets disconnect the time and date RTC registers when the
clock update is in progress: during this time reads may return bogus
values and writes fail silently. This includes the RTC alarm registers.
[1]
cmos_read_alarm() did not take account for that, which caused alarm time
reads to sometimes return bogus values. This can be shown with a test
patch that I am attaching to this patch series.
Fix this, by using mc146818_avoid_UIP().
[1] 7th Generation Intel ® Processor Family I/O for U/Y Platforms [...]
Datasheet, Volume 1 of 2 (Intel's Document Number: 334658-006)
Page 208
https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/7th-and-8th-gen-core-family-mobile-u-y-processor-lines-i-o-datasheet-vol-1.pdf
"If a RAM read from the ten time and date bytes is attempted
during an update cycle, the value read do not necessarily
represent the true contents of those locations. Any RAM writes
under the same conditions are ignored."
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210200131.153887-9-mat.jonczyk@o2.pl
Refactor mc146818_does_rtc_work() so that it uses mc146818_avoid_UIP().
It is enough to call mc146818_avoid_UIP() with no callback.
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210200131.153887-8-mat.jonczyk@o2.pl
Function mc146818_get_time() contains an elaborate mechanism of reading
the RTC time while no RTC update is in progress. It turns out that
reading the RTC alarm clock also requires avoiding the RTC update.
Therefore, the mechanism in mc146818_get_time() should be reused - so
extract it into a separate function.
The logic in mc146818_avoid_UIP() is same as in mc146818_get_time()
except that after every
if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP) {
there is now "mdelay(1)".
To avoid producing a very unreadable patch, mc146818_get_time() will be
refactored to use mc146818_avoid_UIP() in the next patch.
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210200131.153887-6-mat.jonczyk@o2.pl
To prevent an infinite loop in mc146818_get_time(),
commit 211e5db19d ("rtc: mc146818: Detect and handle broken RTCs")
added a check for RTC availability. Together with a later fix, it
checked if bit 6 in register 0x0d is cleared.
This, however, caused a false negative on a motherboard with an AMD
SB710 southbridge; according to the specification [1], bit 6 of register
0x0d of this chipset is a scratchbit. This caused a regression in Linux
5.11 - the RTC was determined broken by the kernel and not used by
rtc-cmos.c [3]. This problem was also reported in Fedora [4].
As a better alternative, check whether the UIP ("Update-in-progress")
bit is set for longer then 10ms. If that is the case, then apparently
the RTC is either absent (and all register reads return 0xff) or broken.
Also limit the number of loop iterations in mc146818_get_time() to 10 to
prevent an infinite loop there.
The functions mc146818_get_time() and mc146818_does_rtc_work() will be
refactored later in this patch series, in order to fix a separate
problem with reading / setting the RTC alarm time. This is done so to
avoid a confusion about what is being fixed when.
In a previous approach to this problem, I implemented a check whether
the RTC_HOURS register contains a value <= 24. This, however, sometimes
did not work correctly on my Intel Kaby Lake laptop. According to
Intel's documentation [2], "the time and date RAM locations (0-9) are
disconnected from the external bus" during the update cycle so reading
this register without checking the UIP bit is incorrect.
[1] AMD SB700/710/750 Register Reference Guide, page 308,
https://developer.amd.com/wordpress/media/2012/10/43009_sb7xx_rrg_pub_1.00.pdf
[2] 7th Generation Intel ® Processor Family I/O for U/Y Platforms [...] Datasheet
Volume 1 of 2, page 209
Intel's Document Number: 334658-006,
https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/7th-and-8th-gen-core-family-mobile-u-y-processor-lines-i-o-datasheet-vol-1.pdf
[3] Functions in arch/x86/kernel/rtc.c apparently were using it.
[4] https://bugzilla.redhat.com/show_bug.cgi?id=1936688
Fixes: 211e5db19d ("rtc: mc146818: Detect and handle broken RTCs")
Fixes: ebb22a0594 ("rtc: mc146818: Dont test for bit 0-5 in Register D")
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210200131.153887-5-mat.jonczyk@o2.pl
There are 4 users of mc146818_get_time() and none of them was checking
the return value from this function. Change this.
Print the appropriate warnings in callers of mc146818_get_time() instead
of in the function mc146818_get_time() itself, in order not to add
strings to rtc-mc146818-lib.c, which is kind of a library.
The callers of alpha_rtc_read_time() and cmos_read_time() may use the
contents of (struct rtc_time *) even when the functions return a failure
code. Therefore, set the contents of (struct rtc_time *) to 0x00,
which looks more sensible then 0xff and aligns with the (possibly
stale?) comment in cmos_read_time:
/*
* If pm_trace abused the RTC for storage, set the timespec to 0,
* which tells the caller that this RTC value is unusable.
*/
For consistency, do this in mc146818_get_time().
Note: hpet_rtc_interrupt() may call mc146818_get_time() many times a
second. It is very unlikely, though, that the RTC suddenly stops
working and mc146818_get_time() would consistently fail.
Only compile-tested on alpha.
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: linux-alpha@vger.kernel.org
Cc: x86@kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210200131.153887-4-mat.jonczyk@o2.pl
No function is checking mc146818_get_time() return values yet, so
correct them to make them more customary.
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210200131.153887-3-mat.jonczyk@o2.pl
Reading from the CMOS involves writing to the index register and then
reading from the data register. Therefore access to the CMOS has to be
serialized with rtc_lock. This invocation of CMOS_READ was not
serialized, which could cause trouble when other code is accessing CMOS
at the same time.
Use spin_lock_irq() like the rest of the function.
Nothing in kernel modifies the RTC_DM_BINARY bit, so there could be a
separate pair of spin_lock_irq() / spin_unlock_irq() before doing the
math.
Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl>
Reviewed-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211210200131.153887-2-mat.jonczyk@o2.pl
I haven’t been able to test this patch as all of my consoles have a
working RTC battery, but according to the documentation it should work
like that.
Signed-off-by: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211215175501.6761-3-linkmauve@linkmauve.fr
These three consoles share a device, the MX23L4005, which contains a
clock and 64 bytes of SRAM storage, and is exposed on the EXI bus
(similar to SPI) on channel 0, device 1. This driver allows it to be
used as a Linux RTC device, where time can be read and set.
The hardware also exposes two timers, one which shuts down the console
and one which powers it on, but these aren’t supported currently.
On the Wii U, the counter bias is stored in a XML file, /config/rtc.xml,
encrypted in the SLC (eMMC storage), using a proprietary filesystem. In
order to avoid having to implement all that, this driver assumes a
bootloader will parse this XML file and write the bias into the SRAM, at
the same location the other two consoles have it.
Signed-off-by: Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211215175501.6761-2-linkmauve@linkmauve.fr
The Epson RX8804 RTC has the same programming model as RV8803.
Add support for it in the driver.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Otavio Salvador <otavio@ossystems.com.br>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211130125830.1166194-2-festevam@gmail.com
As da9063 RTC is not a real I2C client, but relies on da9063 MFD
driver, we need to explicitly mark da9063 RTC as a wakeup source
to be able to access class/rtc/rtcN/wakealarm sysfs entry
to set alarms, so we can wakeup from SHUTDOWN/RTC/DELIVERY mode.
As da9063 driver refuses to load without irq, we simply add it
as a wakeup source before registering rtc device.
Signed-off-by: Nikita Shubin <nikita.shubin@maquefel.me>
Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211129072650.22686-1-nikita.shubin@maquefel.me
Stop using uie_unsupported and clear RTC_FEATURE_UPDATE_INTERRUPT instead.
Also, let the core know that the alarm will truncate seconds as it only has
a minute resolution.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Link: https://lore.kernel.org/r/20211109234750.107115-1-alexandre.belloni@bootlin.com
The pcf85063 driver regsitration currently supports the "compatible"
property type of matching (for DT).
This patch adds "matching by name" support to the driver by defining
an i2c_device_id table and setting the id_table parameter in the
i2c_driver struct.
This will, for example, make the driver easier to instantiate on
systems where CONFIG_OF is not enabled (x86 in my case).
Signed-off-by: Marc Ferland <ferlandm@amotus.ca>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211116164733.17149-1-ferlandm@amotus.ca
In order to make it possible to get battery voltage status, this commit
adds RTC_VL_READ, RTC_VL_CLR ioctl commands to rtc-rs5c372.
Signed-off-by: Camel Guo <camelg@axis.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211111083625.10216-1-camel.guo@axis.com
Subsystem:
- Add new ioctl to get and set extra RTC parameters, this includes backup
switch mode
- Expose available features to userspace, in particular, when alarmas have a
resolution of one minute instead of a second.
- Let the core handle those alarms with a minute resolution
New driver:
- MSTAR MSC313 RTC
Drivers:
- Add SPI ID table where necessary
- Add BSM support for rv3028, rv3032 and pcf8523
- s3c: set RTC range
- rx8025: set range, implement .set_offset and .read_offset
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Merge tag 'rtc-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux
Pull RTC updates from Alexandre Belloni:
"This includes new ioctls to get and set parameters and in particular
the backup switch mode that is needed for some RTCs to actually enable
the backup voltage (and have a useful RTC).
The same interface can also be used to get the actual features
supported by the RTC so userspace has a better way than trying and
failing.
Summary:
Subsystem:
- Add new ioctl to get and set extra RTC parameters, this includes
backup switch mode
- Expose available features to userspace, in particular, when alarmas
have a resolution of one minute instead of a second.
- Let the core handle those alarms with a minute resolution
New driver:
- MSTAR MSC313 RTC
Drivers:
- Add SPI ID table where necessary
- Add BSM support for rv3028, rv3032 and pcf8523
- s3c: set RTC range
- rx8025: set range, implement .set_offset and .read_offset"
* tag 'rtc-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (50 commits)
rtc: rx8025: use .set_offset/.read_offset
rtc: rx8025: use rtc_add_group
rtc: rx8025: clear RTC_FEATURE_ALARM when alarm are not supported
rtc: rx8025: set range
rtc: rx8025: let the core handle the alarm resolution
rtc: rx8025: switch to devm_rtc_allocate_device
rtc: ab8500: let the core handle the alarm resolution
rtc: ab-eoz9: support UIE when available
rtc: ab-eoz9: use RTC_FEATURE_UPDATE_INTERRUPT
rtc: rv3032: let the core handle the alarm resolution
rtc: s35390a: let the core handle the alarm resolution
rtc: handle alarms with a minute resolution
rtc: pcf85063: silence cppcheck warning
rtc: rv8803: fix writing back ctrl in flag register
rtc: s3c: Add time range
rtc: s3c: Extract read/write IO into separate functions
rtc: s3c: Remove usage of devm_rtc_device_register()
rtc: tps80031: Remove driver
rtc: sun6i: Allow probing without an early clock provider
rtc: pcf8523: add BSM support
...
The driver has its own sysfs file to adjust the clock. Fortunately, it is
already in pbb, however, the sign it expects is the opposite of what the
RTC core does (which actually aligns with the RTC).
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211107225458.111068-12-alexandre.belloni@bootlin.com
Tell the RTC core UIE are not supported because the resolution of the alarm
is a minute.
Note that this is in fact also fixing how the resolution is reported as the
previous test was simply ensuring the alarm was more than a minute in the
future while the register has a minute resolution.
This would be ok if the alarm was a countdown but ab8500_rtc_read_alarm
suggests otherwise and the AB8500 datasheet states that the RTC
documentation is not public.
Finally, the comment is wrong and what makes the UIE emulation work is
uie_unsupported being set.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20211107225458.111068-6-alexandre.belloni@bootlin.com
Handle alarms with a minute resolution in the core. Until now drivers have
been open coding the seconds part removal and have been doing that wrongly.
Most of them are rounding up which means the allow the system to miss
deadlines. So, round down and let __rtc_set_alarm return immediately if the
time has already passed.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211107225458.111068-1-alexandre.belloni@bootlin.com
ctrl is set from read_regs(..FLAG, 2, ctrl), so ctrl[0] is FLAG
and ctrl[1] is the CTRL register.
Use ctrl[0] to write back to the FLAG register as appropriate.
Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211101013400.325855-1-dominique.martinet@atmark-techno.com
1. Convert Exynos ChipID and ASV driver to a module and make it a
default, instead of selected. The driver is not essential, so it
could be disabled, if needed.
2. Add support for Exynos850 and Exynos Auto v9 to Exynos ChipID and ASV
driver.
3. Get rid of HAVE_S3C_RTC because it was adding just another layer
instead of direct dependencies.
4. Minor cleanups.
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Merge tag 'samsung-drivers-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux into arm/drivers
Samsung SoC drivers changes for v5.16
1. Convert Exynos ChipID and ASV driver to a module and make it a
default, instead of selected. The driver is not essential, so it
could be disabled, if needed.
2. Add support for Exynos850 and Exynos Auto v9 to Exynos ChipID and ASV
driver.
3. Get rid of HAVE_S3C_RTC because it was adding just another layer
instead of direct dependencies.
4. Minor cleanups.
* tag 'samsung-drivers-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux:
soc: samsung: exynos-chipid: add exynosautov9 SoC support
rtc: s3c: remove HAVE_S3C_RTC in favor of direct dependencies
soc: samsung: exynos-chipid: Add Exynos850 support
dt-bindings: samsung: exynos-chipid: Document Exynos850 compatible
soc: samsung: exynos-chipid: Pass revision reg offsets
soc: samsung: pm_domains: drop unused is_off field
arm64: exynos: don't have ARCH_EXYNOS select EXYNOS_CHIPID
soc: samsung: exynos-chipid: do not enforce built-in
soc: samsung: exynos-chipid: convert to a module
soc: samsung: exynos-chipid: avoid soc_device_to_device()
soc: samsung: exynos-pmu: Fix compilation when nothing selects CONFIG_MFD_CORE
Link: https://lore.kernel.org/r/20211026094709.75692-2-krzysztof.kozlowski@canonical.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
This RTC driver starts counting from 2000 to avoid Y2K problem. Also it
only supports 100 years range for all RTCs. Provide that info to RTC
framework. Also remove check for 100 years range in s3c_rtc_settime(),
as RTC core won't pass any invalid values to the driver, now that
correct range is set.
Here is the rationale on 100 years range limitation. Info on different
Samsung RTCs (credit goes to Krzysztof Kozlowski):
- All S3C chips have only 8-bit wide year register (can store 100
years range in BCD format)
- S5Pv210 and Exynos chips have 12-bit year register (can store 1000
years range in BCD format)
But in reality we usually can't make use of those 12 bits either:
- RTCs might think that both 2000 and 2100 years are leap years. So
when the YEAR register is 0, RTC goes from 28 Feb to 29 Feb, and
when the YEAR register is 100, RTC also goes from 28 Feb to 29 Feb.
This is of course incorrect: RTC breaks leap year criteria, which
breaks the time contiguity, which leads to inability to use the RTC
after year of 2099. It was found for example on Exynos850 SoC.
- Despite having 12 bits for holding the year value, RTC might
overflow the year value internally much earlier. For example, on
Exynos850 the RTC overflows when YEAR=159, making the next YEAR=0.
This way RTC actually has range of 160 years, not 1000 as one may
think.
All that said, there is no sense in trying to increase the time range
for more than 100 years on RTCs that seem capable of that. It also
doesn't have too much practical value -- current hardware will be
probably obsolete by 2100.
Tested manually on Exynos850 RTC:
$ date -s "1999-12-31 23:59:50"
$ hwclock -w -f /dev/rtc0
$ date -s "2100-01-01 00:00:00"
$ hwclock -w -f /dev/rtc0
$ date -s "2000-01-01 00:00:00"
$ hwclock -w -f /dev/rtc0
$ hwclock -r -f /dev/rtc0
$ date -s "2099-12-31 23:59:50"
$ hwclock -w -f /dev/rtc0
$ hwclock -r -f /dev/rtc0
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211021202256.28517-4-semen.protsenko@linaro.org
Create dedicated functions for I/O operations and BCD conversion. It can
be useful to separate those from representation conversion and other
stuff found in RTC callbacks.
This patch does not introduce any functional changes, it's merely
refactoring change.
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211021202256.28517-3-semen.protsenko@linaro.org
devm_rtc_device_register() is deprecated. Use devm_rtc_allocate_device()
and devm_rtc_register_device() API instead. This change doesn't change
the behavior, but allows for further improvements.
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211021202256.28517-2-semen.protsenko@linaro.org
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
Backup Switch Mode allows to select the strategy to use to switch from the
main power supply to the backup power supply. As before, the driver will
switch from standby mode to level mode but now only when it has never been
set.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211018153651.82069-5-alexandre.belloni@bootlin.com
