Re: [PATCH v6 05/11] platform: cznic: turris-omnia-mcu: Add support for MCU watchdog

["Marek Behún" <kabel@kernel.org>]

On Thu, 18 Apr 2024 06:26:04 -0700
Guenter Roeck <linux@roeck-us.net> wrote:

> On Thu, Apr 18, 2024 at 02:11:10PM +0200, Marek Behún wrote:
> > Add support for the watchdog mechanism provided by the MCU.
> > 
> > Signed-off-by: Marek Behún <kabel@kernel.org>  
> 
> This driver should reside in driver/watchdog and use a generic API
> such as regmap to access chip registers.

Hi Guenter,

I have these points against that:

- the regmap API is not applicable in a sane way to the Turris Omnia
  MCU interface. I was trying to do this 5 years ago. An explanation
  can be found at
    https://www.spinics.net/lists/linux-leds/msg11583.html
  (the LED driver uses same interface as the MCU driver, LED controller
   is implemented by the MCU).

  so were the watchdog driver a separate module, we would either need
  to rape the regmap API to do this, or come up with a new API specific
  for Turris Omnia, which seems like an unnecessary complication just
  for one device

- this watchdog is specific for Turris Omnia, the driver can not be
  reused anywhere else

- there are several other multifunction drivers in kernel registering
  watchdog that do not live in drivers/watchdog/

- leaving it in platform/cznic/turris-omnia-mcu* keeps all these
  turris-omnia-mcu features together and they are all implemented
  by one .ko module

Marek