watchdog: pm8916_wdt: Remove redundant of_match_ptr()

The driver depends on CONFIG_OF, it is not necessary to use
of_match_ptr() here.

Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230811062707.2301583-1-ruanjinjie@huawei.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: pm8916_wdt: Handle watchdog enabled by bootloader

The bootloader might already enable the watchdog to catch hangs
during the boot process. In that case the kernel needs to ping
the watchdog temporarily until userspace is fully started.

Add a check for this in the probe() function and set the WDOG_HW_RUNNING
flag to make the watchdog core handle this automatically.

Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220629084816.125515-4-stephan.gerhold@kernkonzept.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: pm8916_wdt: Report reboot reason

The PM8916 PMIC provides "power-off reason" (POFF_REASON) registers
to allow detecting why the board was powered off or rebooted. This
can be used to expose if a reset happened due to a watchdog timeout.
The watchdog API also provides status bits for overtemperature and
undervoltage which happen to be reported in the same PMIC register.

Make this information available as part of the watchdog device
so userspace can decide to handle the situation accordingly.

Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220629084816.125515-3-stephan.gerhold@kernkonzept.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: pm8916_wdt: Avoid read of write-only PET register

PMIC_WD_RESET_PET is a write-only register that is used to ping
the watchdog. It does not make sense to use read-modify-write
for it: a register read will never return anything but zero.
(And actually even if it did we would still want to write again
to ensure the watchdog is pinged.)

Reduce the overhead for the watchdog ping slightly by using
regmap_write() directly instead.

Signed-off-by: Stephan Gerhold <stephan.gerhold@kernkonzept.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220629084816.125515-2-stephan.gerhold@kernkonzept.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: pm8916_wdt: Add system sleep callbacks

Add suspend and resume pm operations.
Tested on dragonboard-410c.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1581435483-6796-1-git-send-email-loic.poulain@linaro.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: pm8916_wdt: fix pretimeout registration flow

When an IRQ is present in the dts, the probe function shall fail if
the interrupt can not be registered.

The probe function shall also be retried if getting the irq is being
deferred.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@linaro.org>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: pm8916_wdt: Use 'dev' instead of dereferencing it repeatedly

Introduce local variable 'struct device *dev' and use it instead of
dereferencing it repeatedly.

The conversion was done automatically with coccinelle using the
following semantic patches. The semantic patches and the scripts
used to generate this commit log are available at
https://github.com/groeck/coccinelle-patches

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: Add pm8916 watchdog driver

The PM816 module is a versatile PMIC with many diverse functions
integrated, including, a watchdog.
This watchdog is subcomponent of the PON (Power On) peripheral,
in the same way as pwrkey/resin buttons.
It works with two timers (2-stages), the first one generates an
IRQ to the main SoC (APQ8016/MSM8916), the second one performs
the reset.

This driver expects the following device hierarchy:
[pm8916]->[pm8916-pon]->[pm8916-wdt]

It uses the pm8916 regmap to access PM8916 registers.

Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>