As Arnd and Guenther suggested, this adds support to the gpio_wdt driver for being a consumer of the clock driving the ripple counter. However, I don't think it should be merged as-is, see below. The first patch makes sense on its own, quick grepping suggests plenty of places that could benefit from this, and I thought it would be odd to have to re-introduce a .remove callback in the gpio_wdt driver. Unfortunately, this turns out to be a bit of an "operation succeeded, patient (almost) died": We use CONFIG_GPIO_WATCHDOG_ARCH_INITCALL because the watchdog has a rather short timeout (1.0-2.25s, 1.6s typical according to data sheet). At first, I put the new code right after the devm_gpiod_get(), but the problem is that this early, we get -EPROBE_DEFER since the clock provider (the RTC which sits off i2c) isn't probed yet. But then the board would reset because it takes way too long for the rest of the machine to initialize. [The bootloader makes sure to turn on the RTC's clock output so the watchdog is actually functional, the task here is to figure out the proper way to prevent clk_disable_unused() from disabling it.] Moving the logic to after the first "is it always-running and if so give it an initial ping" made the board survive, but unfortunately the second, and succesful, probe happens a little more than a second later, which happens to work on this particular board, but is obviously not suitable for production given that it's already above what the spec says, and other random changes in the future might make the gap even wider. So I don't know. The hardware is obviously misdesigned, and I don't know how far the mainline kernel should stretch to support this; OTOH the kernel does contain lots of workarounds for quirks and hardware bugs. Rasmus Villemoes (3): clk: add devm_clk_prepare_enable() helper dt-bindings: watchdog: add optional "delay" clock to gpio-wdt binding watchdog: gpio_wdt: implement support for optional "delay" clock .../devicetree/bindings/watchdog/gpio-wdt.txt | 6 ++++ .../driver-api/driver-model/devres.rst | 1 + drivers/clk/clk-devres.c | 29 +++++++++++++++++++ drivers/watchdog/gpio_wdt.c | 9 ++++++ include/linux/clk.h | 13 +++++++++ 5 files changed, 58 insertions(+) -- 2.29.2
