This second RFC incorporates feedback from the previous RFC: https://lore.kernel.org/linux-watchdog/20220413165104.179144-1-cheloha@xxxxxxxxxxxxx/ v2 changes of note: - Add a firmware feature flag for the H_WATCHDOG feature, FW_FEATURE_WATCHDOG. - Register a platform_device for the first watchdog timer during a pseries initcall if we have FW_FEATURE_WATCHDOG. Use id zero, as there could be more than one timer in the future. - Alphabetize Makefile changes. - Add missing copyright information to pseries-wdt.c. - Add an 'action' module parameter that configures how the guest is terminated on watchdog expiration. - Use dev_*() for logging critical errors instead of pr_*(). - Handle the H_NOOP case when trying to stop the watchdog. If the given watchdog is not actually running, H_WATCHDOG returns H_NOOP. This is harmless, so we should treat it as a success. - We don't need pseries_wdt_remove() at all. - Check watchdog_active() before stopping/starting the timer across suspend/resume. - Consolidate all code from pseries_wdt_module_init() into pseries_wdt_probe(). We can then use module_platform_driver(). I have one lingering question: - The pseries-wdt module is not "automatically" loaded during boot. When I do # modprobe pseries-wdt the driver attaches to the platform bus as expected and the /dev/watchdog* devices for the pseries-wdt.0 platform device are created. I was under the impression that driver/device matching for the platform bus was simple string comparison. ... what am I doing wrong? Is this expected behavior? Do I need to do additional configuration to get the module to load automatically at boot time?
