In the current code, the return value of devm_request_threaded_irq may be
returned. This fixes it.

CC: Alessandro Zummo <a.zummo@towertech.it>
CC: Alexandre Belloni <alexandre.belloni@bootlin.com>
CC: Akshay Bhat <akshay.bhat@timesys.com>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Link: https://lore.kernel.org/r/20191217121231.2698817-2-iwamatsu@nigauri.orgSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Fixes coccicheck warning:

drivers/rtc/rtc-omap.c:619:2-3: Unneeded semicolon
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Link: https://lore.kernel.org/r/1576466353-45384-1-git-send-email-zhengbin13@huawei.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The driver misses a check for devm_clk_get().
Add the check to fix it.
Signed-off-by: Chuhong Yuan <hslester96@gmail.com>
Link: https://lore.kernel.org/r/20191214074528.16806-1-hslester96@gmail.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Remove redundant messages or messages that would not add any value because
the information is already conveyed properly using errno.

Link: https://lore.kernel.org/r/20191223100108.1083078-1-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rv30{2,4}9_register_driver and rv30{2,4}9_unregister_driver are only called
from the init and exit functions of the module. Annotate them properly.

Link: https://lore.kernel.org/r/20191223101430.1091572-1-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The compatibles have been marked obsolete for more that 2 years, drop them
now. Note that this doesn't currently prevent the driver from probing
because the i2c core will still match using the i2c_device_id table.

Link: https://lore.kernel.org/r/20191212230239.65784-1-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Export the 8 byte RAM using nvmem.

Link: https://lore.kernel.org/r/20191214221022.622482-17-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Despite the comment, the RV3029 uses a 7bit BCD register for the year,
making 2079 the last supported year.

Link: https://lore.kernel.org/r/20191214221022.622482-14-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

This allows further improvement of the driver.

Link: https://lore.kernel.org/r/20191214221022.622482-13-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

In case the data is invalid (PON or VLOW2 are set in STATUS, explicitly
tell userspace that the time is invalid. Only remove VLOW2 when setting a
new valid time.

Link: https://lore.kernel.org/r/20191214221022.622482-12-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The RV3029 can report three different conditions: power on, voltage dropped
and data is lost and voltage is low and temperature compensation has
stopped. The first two conditions amount to the same status, the RTC data
is invalid.

VLOW1 has to be cleared manually to resume temperature compensation, this
is achieved using RTC_VL_CLEAR.

Link: https://lore.kernel.org/r/20191214221022.622482-11-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rv3029_read_regs and rv3029_write_regs are simply calling
regmap_bulk_{read,write}. Drop them and call regmap_{,bulk}_{read,write} as
appropriate.

Link: https://lore.kernel.org/r/20191214221022.622482-10-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

It is unecessay to test alarm->enabled before calling
rv3029_alarm_irq_enable.

Link: https://lore.kernel.org/r/20191214221022.622482-9-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Use regmap_update_bits instead of open coding it in
rv3029_alarm_irq_enable.

Link: https://lore.kernel.org/r/20191214221022.622482-8-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

There is no point in having 2 indirections before calling regmap_read,
especially since rv3029_get_sr also changes the return value without any
good reason. Call regmap_read directly.

Link: https://lore.kernel.org/r/20191214221022.622482-7-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

RV3029_STATUS is read in multiple location but its value is never used
afterwards. Avoid this register access when not necessary.

Link: https://lore.kernel.org/r/20191214221022.622482-6-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

There is no lock preventing concurrent access to the status register from
bth the rtc subsystem and the hwmon subsystem. Use regmap_update_bits to
ensure updating RV3029_STATUS is properly locked.

Link: https://lore.kernel.org/r/20191214221022.622482-5-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

rv3029_update_bits open codes regmap_update_bits and forgets to properly
lock the register range while doing so. Use regmap_update_bits instead.

Link: https://lore.kernel.org/r/20191214221022.622482-4-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Instead of trying to validate the accessed registers in custom functions,
let regmap handle that. This allows to defines all the holes in the
register range and gives access to the regmap debugfs register dump.

Link: https://lore.kernel.org/r/20191214221022.622482-3-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The correct name for the rtc is rv3029. c2 is actually the package form
factor rv3029c3 exists and simply has a smaller form factor.

Link: https://lore.kernel.org/r/20191214221022.622482-2-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

RX8010_FLAG_VLF means the voltage dropped too low and data has been lost.

Link: https://lore.kernel.org/r/20191214220259.621996-18-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Remove RTC_VL_CLR handling because it is a disservice to userspace as it
removes the important information that the RTC data is invalid. This may
lead userspace to set an invalid system time later on.

Link: https://lore.kernel.org/r/20191214220259.621996-17-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

RV8803_FLAG_V1F means the voltage is too low to keep the temperature
compensation running and the accuracy of the RTC is affected.

RV8803_FLAG_V2F means the voltage dropped so low that data is now invalid.

Link: https://lore.kernel.org/r/20191214220259.621996-16-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Stop clearing RV8803_FLAG_V2F in RTC_VL_CLR because it is a disservice to
userspace as it removes the important information that the RTC data is
invalid. This may lead userspace to set an invalid system time later on.

Link: https://lore.kernel.org/r/20191214220259.621996-15-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

RV3028_STATUS_PORF means the voltage dropped too low and data has been
lost.

Link: https://lore.kernel.org/r/20191214220259.621996-14-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Remove RTC_VL_CLR handling because it is a disservice to userspace as it
removes the important information that the RTC data is invalid. This may
lead userspace to set an invalid system time later on.

Link: https://lore.kernel.org/r/20191214220259.621996-13-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

PCF85063_REG_SC_OS means the voltage dropped too low and data has been
lost.

Link: https://lore.kernel.org/r/20191214220259.621996-12-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Remove RTC_VL_CLR handling because it is a disservice to userspace as it
removes the important information that the RTC data is invalid. This may
lead userspace to set an invalid system time later on.

Link: https://lore.kernel.org/r/20191214220259.621996-11-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

PCF8563_SC_LV means the voltage dropped too low and data has been lost.

Link: https://lore.kernel.org/r/20191214220259.621996-10-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

voltage_low is only updated when reading the time, this means that using
RTC_VL_READ will miss the VL flag if the time has not been read before
using the ioctl. Always read the status from the hardware.

Link: https://lore.kernel.org/r/20191214220259.621996-9-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Always compile pcf8563_rtc_ioctl as we are sure that CONFIG_RTC_INTF_DEV is
selected on actual kernel configurations.

Link: https://lore.kernel.org/r/20191214220259.621996-8-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Remove RTC_VL_CLR handling because it is a disservice to userspace as it
removes the important information that the RTC data is invalid. This may
lead userspace to set an invalid system time later on.

Link: https://lore.kernel.org/r/20191214220259.621996-7-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

REG_CONTROL3_BLF indicates the battery is low and needs to be replaced
soon.

Link: https://lore.kernel.org/r/20191214220259.621996-6-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

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

ABX8XX_STATUS_BLF indicates the battery is low and needs to be replaced
soon.

Link: https://lore.kernel.org/r/20191214220259.621996-4-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

RTC_VL_READ and RTC_VL_CLR have been introduced in 2012 with commit
0f20b767 ("drivers/rtc/rtc-pcf8563.c: add RTC_VL_READ/RTC_VL_CLR ioctl
feature")

Document them now that they have been unified.

Link: https://lore.kernel.org/r/20191214220259.621996-3-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Currently, the meaning of the value returned by RTC_VL_READ is undocumented
and left to the driver implementation. In order to get more meaningful
values, define a set of values to use as to make clear to userspace what is
the status of the various voltages feeding the RTC.

Link: https://lore.kernel.org/r/20191214220259.621996-2-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

The current use of mode flags to us SPI_MODE_3 and
SPI_CS_HIGH is fragile: it overwrites anything already
assigned by the SPI core. Change it thusly:

- Just |= the SPI_MODE_3 so we keep other flags
- Assign ^= SPI_CS_HIGH since we might be active high
  already, and that is usually the case with GPIOs used
  for chip select, even if they are in practice active low.

Add a comment clarifying why ^= SPI_CS_HIGH is the right
choice here.
Reported-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20191204225731.20306-1-linus.walleij@linaro.orgSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

This allows a subsequent commit to spin_unlock sooner.
Signed-off-by: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Link: https://lore.kernel.org/r/20191128015613.10003-1-jeff.dagenais@gmail.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

Free Electrons is now Bootlin.

Link: https://lore.kernel.org/r/20191210134653.2995661-1-alexandre.belloni@bootlin.comSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>