Re: [PATCH 0/2] add ripple counter dt binding and driver

On Mon, Mar 1, 2021 at 9:34 AM Rasmus Villemoes
[off-list ref] wrote:

On 26/02/2021 20.53, Guenter Roeck wrote:

quoted

Sorry, I am missing something. If the watchdog is controlled by the clock,
it is a consumer of that clock.

But that's just it, the watchdog chip is _not_ a consumer of the clock -
I don't think I've ever seen a gpio_wdt that is not internally clocked,
but even if they exist, that's not the case for this board.

 What else does "consumer" mean ? And why

quoted

not just add optional clock support to the gpio_wdt driver ?

Because, the consumer is a piece of electronics sitting _between_ the
watchdog chip's reset output and the SOCs reset pin, namely the ripple
counter that implements a 64 ms delay from the watchdog fires till the
actual reset. (The watchdog's reset is also routed directly to an
interrupt; so software gets a 64 ms warning that a hard reset is imminent).

I think it's  a question of how you look at what the gpio_wdt device is.
While physical gpio chip is not a consumer of the clock, I agree with
Guenter that the conceptual device is: The functionality of the watchdog
in this case is provided by the combination of the external chip with the
ripple counter. I think it is therefore appropriate to have the gpio_wdt
and the driver refer to the clock as part of the watchdog.

        Arnd