[PATCH v2 0/2] Add the NXP S32 Watchdog

Daniel Lezcano
2025-04-02T15:49:54Z

The NXP S32 watchdog, referenced in the documentation as the Software
Watchdog Timer is actually a hardware watchdog. The system has one
watchdog per core but an assertation does not directly reset the
system as this behavior relies on a particular setup and another
component which is not part of these changes. However the first
watchdog on the system, tied with the Cortex-M4 #0 is a particular
case where it will reset the system directly. This is enough for the
watchdog purpose on Linux.

The watchdog relies on the default timeout described in the device
tree but if another timeout is needed at boot time, it can be changed
with the module parameter.

If the kernel has to service the watchdog in place of the userspace,
it can specify the 'early-enable' option at boot time.

And finally, if starting the watchdog has no wayback then the option
'nowayout' can be also specified in the boot option.

Changelog:

- v2:

- Removed debugfs code as considered pointless for a such simple
driver (Arnd Bergmann)
- Replaced __raw_readl / __raw_writel by readl and writel (Arnd Bergmann)
- Reordered alphabetically the headers (Guenter Roeck)
- Enclosed macro parameter into parenthesis (Guenter Roeck)
- Fixed checkpatch reported errors (Guenter Roeck)
- Clarified a ping on a stopped timer does not affect it (Guenter Roeck)
- Used wdt_is_running() to save an extra IO (Guenter Roeck)
- Fixed a misleading comment about starting the watchdog at boot time (Guenter Roeck)
- Replaced allocation size sizeof(struct ...) by sizeof(*var) (Krzysztof Kozlowski)
- Drop old way of describing the module and use table module device (Krzysztof Kozlowski)
- Replaced additionalProperties by unevaluatedProperties (Rob Herring)
- Removed the DT bindings description as it is obvious (Ghennadi Procopciuc)
- Fixed DT bindings compatible string (Krzysztof Kozlowski)

- v1: initial posting

Daniel Lezcano (2):
dt-bindings: watchdog: Add NXP Software Watchdog Timer
watchdog: Add the Watchdog Timer for the NXP S32 platform

.../bindings/watchdog/nxp,s32g2-swt.yaml | 42 +++
drivers/watchdog/Kconfig | 9 +
drivers/watchdog/Makefile | 1 +
drivers/watchdog/s32g_wdt.c | 313 ++++++++++++++++++
4 files changed, 365 insertions(+)
create mode 100644 Documentation/devicetree/bindings/watchdog/nxp,s32g2-swt.yaml
create mode 100644 drivers/watchdog/s32g_wdt.c

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2.43.0