watchdog: da9062: da9063: use unlocked xfer function in restart

Machine resets via da9062/da9063 PMICs are challenging since one needs
to use special i2c atomic transfers due to the fact interrupts are
disabled in such late system stages. This is the reason both PMICs don't
use regmap and have instead opted for i2c_smbus_write_byte_data() in
restart handlers.

However extensive testing revealed that even using atomic safe function
is not enough and occasional resets fail with error message "Failed to
shutdown (err = -11)". This is due to the fact that function
i2c_smbus_write_byte_data() in turn calls __i2c_lock_bus_helper()
which might fail with -EAGAIN when bus lock is already taken and cannot
be released anymore.

Thus replace i2c_smbus_write_byte_data() with unlocked flavor of
i2c_smbus_xfer() function to avoid above dead-lock scenario. At this
system stage we don't care about proper locking anymore and only want
proper machine reset to be carried out.

Signed-off-by: Primoz Fiser <primoz.fiser@norik.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20221216083645.2574077-1-primoz.fiser@norik.com
[groeck: Fixed continuation line alignment]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: da9063: optionally disable watchdog during suspend

Optionally disable watchdog during suspend (if enabled) and re-enable
it upon resume.
This enables boards to sleep without being interrupted by the watchdog.

This patch is based on commit f6c98b08381c ("watchdog: da9062: add
power management ops") and commit 8541673d2a5f ("watchdog: da9062: fix
power management ops") and brings the same functionality to DA9063.

Signed-off-by: Primoz Fiser <primoz.fiser@norik.com>
Reviewed-by: Adam Thomson <DLG-Adam.Thomson.Opensource@dm.renesas.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220422072713.3172345-2-primoz.fiser@norik.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: da9063: use atomic safe i2c transfer in reset handler

This patch is based on commit 057b52b4b3d5 ("watchdog: da9062: make restart
handler atomic safe"), which uses the atomic transfer capability of the
i2c framework.

Signed-off-by: Yunus Bas <y.bas@phytec.de>
Signed-off-by: Andrej Picej <andrej.picej@norik.com>
Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20211124080654.2601135-1-andrej.picej@norik.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: da9062: da9063: prevent pings ahead of machine reset

Proper machine resets via da9062/da9063 PMICs are very tricky as they
require special i2c atomic transfers when interrupts are not available
anymore. This is also a reason why both PMIC's restart handlers do not
use regmap but instead opt for i2c_smbus_write_byte_data() which does
i2c transfer in atomic manner. Under the hood, this function tries to
obtain i2c bus lock with call to i2c_adapter_trylock_bus() which will
return -EAGAIN (-11) if lock is not available.

Since commit 982bb70517aef ("watchdog: reset last_hw_keepalive time at
start") occasional restart handler failures with "Failed to shutdown
(err = -11)" error messages were observed, indicating that some
process is holding the i2c bus lock. Investigation into the matter
uncovered that sometimes during reboot sequence watchdog ping is issued
late into poweroff/reboot phase which did not happen before mentioned
commit (usually the watchdog ping happened immediately as commit message
suggests). As of now, when watchdog ping usually happens late into
poweroff/reboot stage when interrupts are not available anymore, i2c bus
lock cannot be released anymore and pending restart handler in turn
fails.

Thus, to prevent such late watchdog pings from happening ahead of
pending machine restart and consequently locking up the i2c bus, check
for system_state in watchdog ping handler and consequently do not send
pings anymore in case system_state > SYSTEM_RUNNING.

Signed-off-by: Primoz Fiser <primoz.fiser@norik.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Link: https://lore.kernel.org/r/20210708082128.2832904-1-primoz.fiser@norik.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: da9063: Make use of pre-configured timeout during probe

The watchdog might already be running during boot with a timeout set by
e.g. the bootloader. Make use of this pre-configured timeout instead of
falling back to the default timeout if no device tree value is given.

Signed-off-by: Stefan Riedmueller <s.riedmueller@phytec.de>
Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200403130728.39260-2-s.riedmueller@phytec.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: da9063_wdt: parse DT for timeout value, too

And make sure the final obtained value gets properly scaled. Remove two
empty lines to group the initialization blocks while we are here.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: Steve Twiss <stwiss.opensource@diasemi.com>
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: da9063_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

Cc: Support Opensource <support.opensource@diasemi.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Steve Twiss <stwiss.opensource@diasemi.com>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: da9063: remove duplicated timeout_to_sel calls

Every time da9063_wdt_update_timeout() gets called a timeout_to_sel() is
made because the timeout argument of update_timeout() is the raw
register value. Moving the second<->raw-value translation into
da9063_wdt_update_timeout() removes duplicated code.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Acked-by: Steve Twiss <stwiss.opensource@diasemi.com>
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: da9063: rename helper function to avoid misunderstandings

_da9063_wdt_set_timeout() is called by da9063_wdg_set_timeout(),
da9063_wdg_start() and da9063_wdg_probe() but the name expect only to be
called by da9063_wdg_set_timeout(). Rename the function to avoid
misunderstandings.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Acked-by: Steve Twiss <stwiss.opensource@diasemi.com>
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: da9063: Fix timeout handling during probe

The watchdog can be enabled in previous steps (e.g. the bootloader). Set
the driver default timeout value (8s) if the watchdog is already running
and the HW_RUNNING flag. So the watchdog core framework will ping the
watchdog till the user space activates the watchdog explicit with the
desired timeout value.

Fixes: 5e9c16e37608 ("watchdog: Add DA9063 PMIC watchdog driver.")
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
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: da9063: Fix updating timeout value

The DA9063 watchdog has only one register field to store the timeout value
and to enable the watchdog. The watchdog gets enabled if the value is
not zero. There is no issue if the watchdog is already running but it
leads into problems if the watchdog is disabled.

If the watchdog is disabled and only the timeout value should be prepared
the watchdog gets enabled too. Add a check to get the current watchdog
state and update the watchdog timeout value on hw-side only if the
watchdog is already active.

Fixes: 5e9c16e37608 ("watchdog: Add DA9063 PMIC watchdog driver.")
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
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: da9063: Fix setting/changing timeout

If the timeout value is set more than once the DA9063 watchdog triggers
a reset signal which reset the system.

To update the timeout value we have to disable the watchdog, clear the
watchdog counter value and write the new timeout value to the watchdog.
Clearing the counter value is a feature to be on the safe side because the
data sheet doesn't describe the behaviour of the watchdog counter value
after a watchdog disabling-enable-sequence.

The patch is based on Philipp Zabel's previous patch.

Fixes: 5e9c16e37608 ("watchdog: Add DA9063 PMIC watchdog driver.")
Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
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: add SPDX identifiers for watchdog subsystem

- Add SPDX identifier
- Remove boiler plate license text
- If MODULE_LICENSE and boiler plate does not match, go for boiler plate
license

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Acked-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Acked-by: Keiji Hayashibara <hayashibara.keiji@socionext.com>
Acked-by: Johannes Thumshirn <jth@kernel.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Mans Rullgard <mans@mansr.com>
Acked-by: Matthias Brugger <matthias.bgg@gmail.com>
Acked-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Tomas Winkler <tomas.winkler@intel.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: da9063_wdt: Simplify by removing unneeded struct...

...da9063_watchdog, which contained nothing but struct watchdog_device and a
struct da9063 pointer.
Assign the struct da9063 pointer directly to the struct watchdog_device's
driver_data field instead of creating struct da9063_watchdog and assigning
it's address there.
Spares a pointer's size data memory and an indirection level in the callbacks.

Signed-off-by: Karsten Wiese <fzuuzf@googlemail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: da9063_wdt: Convert to use device managed functions

Use device managed functions to simplify error handling, reduce
source code size, improve readability, and reduce the likelyhood of bugs.

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

- Replace 'val = e; return val;' with 'return e;'
- Replace 'if (e) return e; return 0;' with 'return e;'
- Drop assignments to otherwise unused variables
- Drop unused variables
- Drop remove function
- Drop dev_set_drvdata()
- Use devm_watchdog_register_driver() to register watchdog device

Acked-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

watchdog: da9063_wdt: don't trigger watchdog too fast

Triggering the watchdog faster than T_WDMIN=256ms leads to resets of the
DA9063 chip. The datasheet says that the watchdog must only be triggered
in the timeframe T_WDMIN to T_WDMAX. The T_WDMAX is configured in the
driver.

Signed-off-by: Stefan Christ <s.christ@phytec.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: Add 'action' and 'data' parameters to restart handler callback

The 'action' (or restart mode) and data parameters may be used by restart
handlers, so they should be passed to the restart callback functions.

Cc: Sylvain Lemieux <slemieux@tycoint.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: da9063_wdt: use core restart handler

Get rid of the custom restart handler by using the one provided by the
watchdog core.

Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Watchdog: Fix parent of watchdog_devices

/sys/class/watchdog/watchdogn/device/modalias can help to identify the
driver/module for a given watchdog node. However, many wdt devices do not
set their parent and so, we do not see an entry for device in sysfs for
such devices.

This patch fixes parent of watchdog_device so that
/sys/class/watchdog/watchdogn/device is populated.

Exceptions: booke, diag288, octeon, softdog and w83627hf -- They do not
have any parent. Not sure, how we can identify driver for these devices.

Signed-off-by: Pratyush Anand <panand@redhat.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Lubomir Rintel <lkundrak@v3.sk>
Acked-by: Maxime Coquelin <maxime.coquelin@st.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: da9063: Add restart handler support

Register a restart handler for the da9063 watchdog. System restart is
triggered by sending the shutdown command to the PMIC.
As more-suitable restart handlers may exist, the priority of the
watchdog restart handler is set to 128.

The actual restart method was inspired by a platform-specific patch from
the BSP by Hisashi Nakamura <hisashi.nakamura.ak@renesas.com>.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Steve Twiss <stwiss.opensource@diasemi.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: Add DA9063 PMIC watchdog driver.

This driver supports the watchdog device inside the DA9063 PMIC.

Signed-off-by: Krystian Garbaciak <krystian.garbaciak@diasemi.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Steve Twiss <stwiss.opensource@diasemi.com>
Tested-by: Steve Twiss <stwiss.opensource@diasemi.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>