rtc: pcf2127: remove useless check

This check is only useful when introducing support for a new RTC in the
driver. Cut down the number of strings in th driver.

Link: https://lore.kernel.org/r/20230827214649.537095-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: remove unused function argument

Fixes the following W=1 kernel build warning(s):

drivers/rtc/rtc-pcf2127.c: In function ‘pcf2127_probe’:
drivers/rtc/rtc-pcf2127.c:635:32: warning: unused parameter ‘name’ [-Wunused-parameter]
635 | int alarm_irq, const char *name, bool is_pcf2127)
| ~~~~~~~~~~~~^~~~

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230801190432.3340545-1-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: add error checking when disabling POR0

If PCF2127 device is absent from the I2C bus, or if there is a
communication problem, disabling POR0 may fail silently and we
still continue with probing the device. In that case, abort probe
operation.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230728171211.3016019-1-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: fix error code in pcf2127_enable_ts()

This error path accidentally returns success. Return -EINVAL instead.

Fixes: 420cc9e850db ("rtc: pcf2127: add support for multiple TS functions")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Reviewed-by: Hugo Villeneuve <hugo@hugovil.com>
Reviewed-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/55b9c84b-9d21-444f-b91a-cf9316b65833@moroto.mountain
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: add UIE support for PCF2131

The PCF2127/29 do NOT support alarms with a 1 second resolution, but
the PCF2131 does.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-17-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: add flag for watchdog register value read support

The watchdog value register cannot be read on the PCF2131 after being
set.

Add a new flag to identify which variant has read access to this
register, and use this flag to selectively test if watchdog timer was
started by bootloader.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-16-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: support generic watchdog timing configuration

Introduce in the configuration structure two new values to hold the
watchdog clock source and the min_hw_heartbeat_ms value.

The minimum and maximum timeout values are automatically computed from
the watchdog clock source value for each variant.

The PCF2131 has no 1Hz watchdog clock source, as is the case for
PCF2127/29.

The next best choice is using a 1/4Hz clock, giving a watchdog timeout
range between 4 and 1016s. By using the same register configuration as
for the PCF2127/29, the 1/4Hz clock source is selected.

Note: the PCF2127 datasheet gives a min/max range between 1 and 255s,
but it should be between 2 and 254s, because the watchdog is triggered
when the timer value reaches 1, not 0.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-15-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: adapt time/date registers write sequence for PCF2131

The sequence for updating the time/date registers is slightly
different between PCF2127/29 and PCF2131.

For PCF2127/29, during write operations, the time counting
circuits (memory locations 03h through 09h) are automatically blocked.

For PCF2131, time/date registers write access requires setting the
STOP bit and sending the clear prescaler instruction (CPR). STOP then
needs to be released once write operation is completed.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-14-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: add support for PCF2131 interrupts on output INT_A

The PCF2127 and PCF2129 have one output interrupt pin. The PCF2131 has
two, named INT_A and INT_B. The hardware support that any interrupt
source can be routed to either one or both of them.

Force all interrupt sources to go to the INT A pin.

Support to route any interrupt source to INT A/B pins is not supported
by this driver at the moment.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-13-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: add support for PCF2131 RTC

This RTC is very similar in functionality to the PCF2127/29.

Basically it:
-supports two new control registers at offsets 4 and 5
-supports a new reset register (not implemented in this driver)
-supports 4 tamper detection functions instead of 1
-has no nvmem (like the PCF2129)
-has two output interrupt pins

Because of that, most of the register addresses are very different,
although they still follow the same layout. For example, the tamper
registers have a different base address, but the offsets are all the same.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-12-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: add support for multiple TS functions

This will simplify the implementation of new variants into this driver.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-11-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: adapt for CLKOUT register at any offset

This will simplify the implementation of new variants into this driver.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-10-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: adapt for WD registers at any offset

This will simplify the implementation of new variants into this driver.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Tested-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-9-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: adapt for alarm registers at any offset

This will simplify the implementation of new variants into this driver.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-8-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: adapt for time/date registers at any offset

This will simplify the implementation of new variants into this driver.

Some variants (PCF2131) have a 100th seconds register. This register is
currently not supported in this driver.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-7-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: add variant-specific configuration structure

Create variant-specific configuration structures to simplify the
implementation of new variants into this driver. It will also avoid
to have too many tests for a specific variant, or a list of variants
for new devices, inside the code itself.

Add configuration options for the support of the NVMEM, bit CD0 in
register WD_CTL as well as the maximum number of registers for each
variant, instead of hardcoding the variant (PCF2127) inside the
i2c_device_id and spi_device_id structures.

Also specify a different maximum number of registers (max_register)
for the PCF2129.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-6-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: remove superfluous comments

Noted while reviewing new PCF2131 driver.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-5-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: lower message severity if setting time fails

Noted while reviewing new PCF2131 driver.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-4-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: improve timestamp reading performance

Reading the 7 timetamp registers currently involves reading 25 registers
solely to be able to print the content of the three control registers,
in addition to the 7 timestamp registers. This print never occurs,
unless the user enables dynamic debug in this driver or set
CONFIG_RTC_DEBUG.

Reading the timestamp registers should consist of reading 7
consecutive timestamp registers.

This patch optimize the performance of reading the timestamp registers
by reading 7 consecutive registers instead of 25, and dropping the
print of the control registers.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-3-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: improve rtc_read_time() performance

Improve performance and readability of rtc_read_time() by reading only
the 7 time registers, instead of reading 8 registers (additional CTRL3
register).

We drop reading of CTRL3 to monitor the low battery flag, as this
check is already available in the ioctl. Anyway, this check only
display an info message and has no other impacts.

The code readability also improves as we do not have to fiddle with
buffer pointer and size arithmetic.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20230622145800.2442116-2-hugo@hugovil.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: Switch i2c drivers back to use .probe()

After commit b8a1a4cd5a98 ("i2c: Provide a temporary .probe_new()
call-back type"), all drivers being converted to .probe_new() and then
03c835f498b5 ("i2c: Switch .probe() to not take an id parameter") convert
back to (the new) .probe() to be able to eventually drop .probe_new() from
struct i2c_driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230505121136.1185653-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: Convert to .probe_new()

.probe_new() doesn't get the i2c_device_id * parameter, so determine
that explicitly in .probe(). The device_id array has to move up for that
to work.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20221021130706.178687-7-u.kleine-koenig@pengutronix.de
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: set RTC_FEATURE_ALARM_RES_2S

The PCF2127 doesn't support UIE because setting an alarm to fire every
second confuses the chip and the fastest we can go is an alarm every 2
seconds.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220309162301.61679-11-alexandre.belloni@bootlin.com

rtc: pcf2127: switch to RTC_FEATURE_UPDATE_INTERRUPT

Stop using uie_unsupported and clear RTC_FEATURE_UPDATE_INTERRUPT instead.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220309162301.61679-10-alexandre.belloni@bootlin.com

rtc: pcf2127: fix bug when reading alarm registers

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

rtc: pcf2127: use IRQ flags obtained from device tree if available

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

rtc: pcf2127: Fix typo in comment

Replace TFS2 with TSF2.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20211207215626.2619819-1-hugo@hugovil.com

rtc: pcf2127: handle timestamp interrupts

commit 03623b4b041c ("rtc: pcf2127: add tamper detection support")
added support for timestamp interrupts. However they are not being
handled in the irq handler. If a timestamp interrupt occurs it
results in kernel disabling the interrupt and displaying the call
trace:

[ 121.145580] irq 78: nobody cared (try booting with the "irqpoll" option)
...
[ 121.238087] [<00000000c4d69393>] irq_default_primary_handler threaded [<000000000a90d25b>] pcf2127_rtc_irq [rtc_pcf2127]
[ 121.248971] Disabling IRQ #78

Handle timestamp interrupts in pcf2127_rtc_irq(). Save time stamp
before clearing TSF1 and TSF2 flags so that it can't be overwritten.
Set a flag to mark if the timestamp is valid and only report to sysfs
if the flag is set. To mimic the hardware behavior, don’t save
another timestamp until the first one has been read by the userspace.

However, if the alarm irq is not configured, keep the old way of
handling timestamp interrupt in the timestamp0 sysfs calls.

Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Tested-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210629150643.31551-1-ykaukab@suse.de

rtc: pcf2127: Fix the datasheet URL

The current datasheet URL is no longer valid.

Replace with a valid one.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210603143447.2223353-1-festevam@gmail.com

rtc: pcf2127: properly set flag WD_CD for rtc chips(pcf2129, pca2129)

Properly set flag WD_CD for rtc chips(pcf2129, pca2129)

Signed-off-by: Biwen Li <biwen.li@nxp.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201202031840.15582-1-biwen.li@oss.nxp.com

rtc: pcf2127: Run a OTP refresh if not done before

The datasheet of the PCF2127 states, it is recommended to process an OTP
refresh once the power is up and the oscillator is operating stable. The
OTP refresh takes less than 100 ms to complete.

Signed-off-by: Philipp Rosenberger <p.rosenberger@kunbus.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210118085752.5759-3-p.rosenberger@kunbus.com

rtc: pcf2127: Disable Power-On Reset Override

To resume normal operation after a total power loss (no or empty
battery) the "Power-On Reset Override (PORO)" facility needs to be
disabled.

The register reset value sets the PORO enabled and the data sheet
recommends setting it to disabled for normal operation.

From what I've seen on the PCF2127 and PCF2129 there is no event
generated at the interrupt pin (INT), as long the PORO bit is set. This
behavior is not documented in the manual.

Signed-off-by: Philipp Rosenberger <p.rosenberger@kunbus.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210118085752.5759-2-p.rosenberger@kunbus.com

rtc: pcf2127: remove pcf2127_rtc_alrm_ops

Move the alarm callbacks in pcf2127_rtc_ops and use RTC_FEATURE_ALARM to
signal to the core whether alarms are available instead of having a
supplementary struct rtc_class_ops without alarm callbacks.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20210110231752.1418816-8-alexandre.belloni@bootlin.com

rtc: pcf2127: only use watchdog when explicitly available

Most boards using the pcf2127 chip (in my bubble) don't make use of the
watchdog functionality and the respective output is not connected. The
effect on such a board is that there is a watchdog device provided that
doesn't work.

So only register the watchdog if the device tree has a "reset-source"
property.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[RV: s/has-watchdog/reset-source/]
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201218101054.25416-3-rasmus.villemoes@prevas.dk

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: add devm_ prefix to rtc_nvmem_register()

rtc_nvmem_register() is a managed interface. It doesn't require any
release function to be called at driver detach. To avoid confusing
driver authors, let's rename it to devm_rtc_nvmem_register() and add it
to the list of managed interfaces in Documentation/.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201109163409.24301-6-brgl@bgdev.pl

rtc: pcf2127: fix pcf2127_nvmem_read/write() returns

These functions should return zero on success. Non-zero returns are
treated as error. On some paths, this doesn't matter but in
nvmem_cell_read() a non-zero return would be passed to ERR_PTR() and
lead to an Oops.

Fixes: d6c3029f32f7 ("rtc: pcf2127: add support for accessing internal static RAM")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20201022070451.GA2817669@mwanda

rtc: pcf2127: move watchdog initialisation to a separate function

The obvious advantages are:

- The linker can drop the watchdog functions if CONFIG_WATCHDOG is off.
- All watchdog stuff grouped together with only a single function call
left in generic code.
- Watchdog register is only read when it is actually used.
- Less #ifdefery

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20200924105256.18162-2-u.kleine-koenig@pengutronix.de

rtc: pcf2127: fix a bug when not specify interrupts property

Fix a bug when not specify interrupts property in dts
as follows,
rtc-pcf2127-i2c 1-0051: failed to request alarm irq
rtc-pcf2127-i2c: probe of 1-0051 failed with error -22

Signed-off-by: Biwen Li <biwen.li@nxp.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20200915073213.12779-1-biwen.li@oss.nxp.com

rtc: pcf2127: fix alarm handling

Fix multiple issues when handling alarms:
- Use threaded interrupt to avoid scheduling when atomic
- Stop matching on week day as it may not be set correctly
- Avoid parsing the DT interrupt and use what is provided by the i2c or
spi subsystem
- Avoid returning IRQ_NONE in case of error in the interrupt handler
- Never write WDTF as specified in the datasheet
- Set uie_unsupported, as for the pcf85063, setting alarms every seconds
is not working correctly and confuses the RTC.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20200812085114.474903-1-alexandre.belloni@bootlin.com

rtc: pcf2127: add alarm support

Add alarm support for the pcf2127 RTC chip family.
Tested on pca2129.

Signed-off-by: Liam Beguin <lvb@xiphos.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20200630024211.12782-3-liambeguin@gmail.com

rtc: pcf2127: add pca2129 device id

The PCA2129 is the automotive grade version of the PCF2129.
add it to the list of compatibles.

Signed-off-by: Liam Beguin <lvb@xiphos.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20200630024211.12782-2-liambeguin@gmail.com

rtc: pcf2127: watchdog: handle nowayout feature

Driver does not use module parameter for nowayout, so it need to
statically initialize status variable of the watchdog_device based
on CONFIG_WATCHDOG_NOWAYOUT.

Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200604162602.76524-1-bruno.thomsen@gmail.com

rtc: pcf2127: report battery switch over

Add support for the RTC_VL_BACKUP_SWITCH flag to report battery switch over
events.

Link: https://lore.kernel.org/r/20200511140335.799133-1-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: set regmap max_register

Set regmap max_register to ease debugging and enforce the register range.

Link: https://lore.kernel.org/r/20200505201310.255145-4-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: remove unnecessary #ifdef

There is not point in setting .ioctl to NULL when CONFIG_RTC_INTF_DEV is
not defined because it would not be called anyway.

Link: https://lore.kernel.org/r/20200505201310.255145-3-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: let the core handle rtc range

Let the core handle offsetting and windowing the RTC range.

Link: https://lore.kernel.org/r/20200505201310.255145-2-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: return meaningful value for RTC_VL_READ

PCF2127_BIT_CTRL3_BLF indicates the battery is low and needs to be replaced
soon.

Link: https://lore.kernel.org/r/20191214220259.621996-5-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: handle boot-enabled watchdog feature

Linux should handle when the pcf2127 watchdog feature is enabled by the
bootloader. This is done by checking the watchdog timer value during
init, and set the WDOG_HW_RUNNING flag if the value differs from zero.

Signed-off-by: Martin Hundebøll <martin@geanix.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191021080838.2789-1-martin@geanix.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: bugfix: watchdog build dependency

Disable watchdog registation when kernel is build without
watchdog functionality, and enable watchdog core otherwise.
This removes compile errors like the one below:

drivers/rtc/rtc-pcf2127.o: in function `pcf2127_probe.constprop.3':
rtc-pcf2127.c:(.text.unlikely+0x2c8): undefined reference to
`devm_watchdog_register_device'

Watchdog feature in chip will always be configured as
this is safe to do in both cases and minimize code churn.

Reported-by: Hulk Robot <hulkci@huawei.com>
Reported-by: YueHaibing <yuehaibing@huawei.com>
Fixes: bbc597561ce1 ("rtc: pcf2127: add watchdog feature support")
Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20190827143656.4734-1-bruno.thomsen@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: add tamper detection support

Add support for integrated tamper detection function in both PCF2127 and
PCF2129 chips. This patch implements the feature by adding an additional
timestamp0 file to sysfs device path. This file contains seconds since
epoch, if an event occurred, or is empty, if none occurred.
Interface should match ISL1208 and RV3028 RTC drivers.

Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20190822131936.18772-5-bruno.thomsen@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: add watchdog feature support

Add partial support for the watchdog functionality of
both PCF2127 and PCF2129 chips.

The programmable watchdog timer is currently using a fixed
clock source of 1Hz. This result in a selectable range of
1-255 seconds, which covers most embedded Linux use-cases.

Clock sources of 4096Hz, 64Hz and 1/60Hz is mostly useful
in MCU use-cases.

Countdown timer not available when using watchdog feature.

Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20190822131936.18772-4-bruno.thomsen@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: bugfix: read rtc disables watchdog

The previous fix listed bulk read of registers as root cause of
accendential disabling of watchdog, since the watchdog counter
register (WD_VAL) was zeroed.

Fixes: 3769a375ab83 rtc: pcf2127: bulk read only date and time registers.

Tested with the same PCF2127 chip as Sean reveled root cause
of WD_VAL register value zeroing was caused by reading CTRL2
register which is one of the watchdog feature control registers.

So the solution is to not read the first two control registers
(CTRL1 and CTRL2) in pcf2127_rtc_read_time as they are not
needed anyway. Size of local buf variable is kept to allow
easy usage of register defines to improve readability of code.

Debug trace line was updated after CTRL1 and CTRL2 are no longer
read from the chip. Also replaced magic numbers in buf access
with register defines.

Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20190822131936.18772-3-bruno.thomsen@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: cleanup register and bit defines

Cleanup of defines to follow kernel coding style and increase code
readability by using same register and bit define style.

Change PCF2127_REG_RAM_{addr_MSB,wrt_cmd,rd_cmd} to upper case as
kernel coding guide section 12 'Macros, Enums and RTL' states
"Names of macros defining constants and labels in enums are capitalized".

Improve readability of RAM register comment by making whole sentences.

Remove parentheses from register defines as they are only used
for expressions and not constants.

As there are no clear style for name of registers and bits in the
kernel drivers, I suggest the following for at least this driver,
but hopefully also other RTC drivers.

Register name should follow this convention:
[chip]_REG_[reg name] 0xXX

Bit name should follow this convention, so it clearly states which
chip register it's part of:
[chip]_BIT_[reg name]_[bit name] BIT(X)

Additionally I suggest bit defines are always placed right below
its corresponding register define and using an extra tab indentation
for the BIT(X) part. This will visually make it easy to see that bit
defines are part of the complete register definition.

Rename PCF2127_OSF to PCF2127_BIT_SC_OSF and move it right below
PCF2127_REG_SC. This will improve readability of bit checks as it's
easy to verify that it uses the correct register.

Move end of line comments above register defines as it's more like
a heading for 1 register define and up to 8 bit defines or a
collection of registers that are close related like timestamp
split across 6 registers.

Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20190822131936.18772-2-bruno.thomsen@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: convert to devm_rtc_allocate_device

This allows further improvement of the driver.

Signed-off-by: Bruno Thomsen <bruno.thomsen@gmail.com>
Link: https://lore.kernel.org/r/20190822131936.18772-1-bruno.thomsen@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 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 version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

rtc: pcf2127: fix a kmemleak caused in pcf2127_i2c_gather_write

pcf2127_i2c_gather_write() allocates memory as local variable
for i2c_master_send(), after finishing the master transfer,
the allocated memory should be freed. The kmemleak is reported:

unreferenced object 0xffff80231e7dba80 (size 64):
comm "hwclock", pid 27762, jiffies 4296880075 (age 356.944s)
hex dump (first 32 bytes):
03 00 12 03 19 02 11 13 00 80 98 18 00 00 ff ff ................
00 50 00 00 00 00 00 00 02 00 00 00 00 00 00 00 .P..............
backtrace:
[<ffff000008221398>] create_object+0xf8/0x278
[<ffff000008a96264>] kmemleak_alloc+0x74/0xa0
[<ffff00000821070c>] __kmalloc+0x1ac/0x348
[<ffff0000087ed1dc>] pcf2127_i2c_gather_write+0x54/0xf8
[<ffff0000085fd9d4>] _regmap_raw_write+0x464/0x850
[<ffff0000085fe3f4>] regmap_bulk_write+0x1a4/0x348
[<ffff0000087ed32c>] pcf2127_rtc_set_time+0xac/0xe8
[<ffff0000087eaad8>] rtc_set_time+0x80/0x138
[<ffff0000087ebfb0>] rtc_dev_ioctl+0x398/0x610
[<ffff00000823f2c0>] do_vfs_ioctl+0xb0/0x848
[<ffff00000823fae4>] SyS_ioctl+0x8c/0xa8
[<ffff000008083ac0>] el0_svc_naked+0x34/0x38
[<ffffffffffffffff>] 0xffffffffffffffff

Signed-off-by: Xulin Sun <xulin.sun@windriver.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rtc: pcf2127: add support for accessing internal static RAM

The PCF2127 has 512 bytes of internal static RAM and this patch expands
the driver to access this memory.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
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: pcf2127: bulk read only date and time registers.

Read control registers one by one and bulk read time registers.
This fixes when the clock is read, the watchdog counter register is zeroed.

Signed-off-by: Sean Nyekjaer <sean.nyekjaer@prevas.dk>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: pcf2127: add pcf2129 device id

There are only a few differences between PCF2127 and PCF2129 (PCF2127
has 512 bytes of general purpose SRAM and count-down timer).

The rtc-pcf2127 driver currently doesn't use the PCF2127 specific
functionality and Kconfig help text already says this driver supports
PCF2127/29, so we can simply add pcf2129 to device id list.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: pcf2127: add support for spi interface

pcf2127 has selectable I2C-bus and SPI-bus interface support.

This adds support for SPI interface.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: pcf2127: convert to use regmap

pcf2127 has selectable I2C-bus and SPI-bus interface support.
Currently rtc-pcf2127 driver only supports I2C.

This is preparation for support for SPI interface.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: pcf2127: remove useless driver version

A driver version is only really sensible for oot drivers. Also the
dev_info about having found a chip only signals that allocating the
driver data succeeded and so isn't worth much.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: pcf2127: fix reading uninitialized value on RTC_READ_VL ioctl

The flag reported on the RTC_READ_VL ioctl is only initialized when the
date is read out. So the voltage low value doesn't represent reality but
the status at the time the date was read (or 0 if the date was not read
yet).

Moreover when userspace requests a value via an ioctl there is no added
benefit to also make a prosa representation of this (and other) values
appear in the kernel log so remove the calls to dev_info and the driver
data members to track their state.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: pcf2127: make module license match the file header

The header of the pcf2127 driver specifies GPL v2 only as license, so
use "GPL v2" as module license specifier instead of "GPL" as the latter
means "GNU Public License v2 or later".

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: Drop owner assignment from i2c_driver

i2c_driver does not need to set an owner because i2c_register_driver()
will set it.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: pcf2127: use OFS flag to detect unreliable date and warn the user

The PCF2127 datasheet states that it's wrong to say that the date in
unreliable if BLF (battery low flag) is set but instead, OSF (seconds
register) should be used to check if oscillator, for any reason, stopped.
Battery may be low (usually below 2V5 threshold) but the date may be anyway
correct (typically date is unreliable when input voltage is below 1V2).

Signed-off-by: Andrea Scian <andrea.scian@dave.eu>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

rtc: use rtc_valid_tm() error code when reading date/time

There's a wrong comment in some RTC drivers that say it's better to ignore
rtc_valid_tm() when reading RTC timestamp. However this is wrong and is
better to return to the userspace the error if timestamp is not valid.

Signed-off-by: Andrea Scian <andrea.scian@dave.eu>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/rtc-pcf2127.c: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO

Fix a coccinelle error regarding usage of IS_ERR and PTR_ERR instead of
PTR_ERR_OR_ZERO.

Signed-off-by: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-pcf2127.c: remove empty function

The 'remove' function is empty and does not do anything. Delete it.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

rtc: add NXP PCF2127 support (i2c)

Added support for NXP PCF2127 RTC (i2c).

[akpm@linux-foundation.org: fix typo, fix warnings]
Signed-off-by: Renaud Cerrato <r.cerrato@til-technologies.fr>
Cc: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>