watchdog: stm32_iwdg: initialize default timeout

The driver never sets a default timeout value, therefore it is
initialized to zero. When CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is
enabled, the watchdog is started during probe. The kernel is supposed to
automatically ping the watchdog from this point until userspace takes
over, but this does not happen if the configured timeout is zero. A zero
timeout causes watchdog_need_worker() to return false, so the heartbeat
worker does not run and the system therefore resets soon after the
driver is probed.

This patch fixes this by setting an arbitrary non-zero default timeout.
The default could be read from the hardware instead, but I didn't see
any reason to add this complexity.

This has been tested on an STM32F746.

Fixes: 85fdc63fe256 ("drivers: watchdog: stm32_iwdg: set WDOG_HW_RUNNING at probe")
Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20240228182723.12855-1-ben.wolsieffer@hefring.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: stm32: Drop unnecessary of_match_ptr()

With COMPILE_TEST recently enabled, 0-day reports a warning:

drivers/watchdog/stm32_iwdg.c:215:34: warning: 'stm32_iwdg_of_match' defined but not used [-Wunused-const-variable=]

As STM32 platforms are always used with DT, drop the of_match_ptr().

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202308211837.4VBSUAtZ-lkp@intel.com/
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230823151059.2356881-1-robh@kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it was merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Alim Akhtar <alim.akhtar@samsung.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230726233302.3812749-1-robh@kernel.org
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: stm32_iwdg: drop superfluous error message

In the function stm32_iwdg_probe(), devm_platform_ioremap_resource
has already contained error message, so drop the redundant one.

Co-developed-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Zhang Shengju <zhangshengju@cmss.chinamobile.com>
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210814142741.7396-1-tangbin@cmss.chinamobile.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: stm32_iwdg: don't print an error on probe deferral

Do not print an error trace when deferring probe for clock resources.

Signed-off-by: Etienne Carriere <etienne.carriere@st.com>
Signed-off-by: Christophe Roullier <christophe.roullier@st.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20201106142327.3129-2-christophe.roullier@st.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers: watchdog: stm32_iwdg: set WDOG_HW_RUNNING at probe

If the watchdog hardware is already enabled during the boot process,
when the Linux watchdog driver loads, it should start/reset the watchdog
and tell the watchdog framework. As a result, ping can be generated from
the watchdog framework (if CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED is set),
until the userspace watchdog daemon takes over control

Fixes:4332d113c66a ("watchdog: Add STM32 IWDG driver")

Signed-off-by: Christophe Roullier <christophe.roullier@st.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191122132246.8473-1-christophe.roullier@st.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: stm32_iwdg: drop warning after registering device

The core will print out details now.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: stm32: add dynamic prescaler support

This patch allows to define the max prescaler by compatible.
To set a large range of timeout, the prescaler should be set
dynamically (from the timeout request) to improve the resolution
in order to have a timeout close to the expected value.

Signed-off-by: Ludovic Barre <ludovic.barre@st.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: stm32_iwdg: drop warning after calling watchdog_init_timeout

The core will print out details now.

Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: stm32_iwdg: Convert to use device managed functions and other improvements

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

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

- Drop assignments to otherwise unused variables
- Drop empty remove function
- Use devm_add_action_or_reset() for calls to clk_disable_unprepare
- Introduce local variable 'struct device *dev' and use it instead of
dereferencing it repeatedly
- Use devm_watchdog_register_driver() to register watchdog device

Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: Convert to use devm_platform_ioremap_resource

Use devm_platform_ioremap_resource to reduce source code size,
improve readability, and reduce the likelyhood of bugs.

The conversion was done automatically with coccinelle using the
following semantic patch.

@r@
identifier res, pdev;
expression a;
expression index;
expression e;
@@

<+...
- res = platform_get_resource(pdev, IORESOURCE_MEM, index);
- a = devm_ioremap_resource(e, res);
+ a = devm_platform_ioremap_resource(pdev, index);
...+>

@depends on r@
identifier r.res;
@@
- struct resource *res;
... when != res

@@
identifier res, pdev;
expression index;
expression a;
@@
- struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, index);
- a = devm_ioremap_resource(&pdev->dev, res);
+ a = devm_platform_ioremap_resource(pdev, index);

Cc: Joel Stanley <joel@jms.id.au>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Keguang Zhang <keguang.zhang@gmail.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Avi Fishman <avifishman70@gmail.com>
Cc: Nancy Yuen <yuenn@google.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Barry Song <baohua@kernel.org>
Cc: Orson Zhai <orsonzhai@gmail.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Marc Gonzalez <marc.w.gonzalez@free.fr>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Acked-by: Michal Simek <michal.simek@xilinx.com> (cadence/xilinx wdts)
Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: stm32: add pclk feature for stm32mp1

This patch adds compatible data to manage pclk clock by
compatible. Adds stm32mp1 support which requires pclk clock.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Acked-by: Alexandre TORGUE <alexandre.torgue@st.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: stm32: Fix copyright

Uniformize STMicroelectronics copyrights header
Add SPDX identifier

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Acked-by: Alexandre TORGUE <alexandre.torgue@st.com>
CC: Yannick Fertre <yannick.fertre@st.com>
Acked-by: Yannick Fertre <yannick.fertre@st.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: stm32_iwdg: constify watchdog_ops structure

Check for watchdog_ops structures that are only stored in the ops field of
a watchdog_device structure. This field is declared const, so watchdog_ops
structures that have this property can be declared as const also.

This issue was detected using Coccinelle and the following semantic patch:

@r
disable optional_qualifier@
identifier i;
position p;
@@
static struct watchdog_ops i@p = { ... };

@ok@
identifier r.i;
struct watchdog_device e;
position p;
@@
e.ops = &i@p;

@bad@
position p != {r.p,ok.p};
identifier r.i;
struct watchdog_ops e;
@@
e@i@p

@depends on !bad disable optional_qualifier@
identifier r.i;
@@
static
+const
struct watchdog_ops i = { ... };

Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.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: Add STM32 IWDG driver

This patch adds IWDG (Independent WatchDoG) support for STM32 platform.

Signed-off-by: Yannick FERTRE <yannick.fertre@st.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>