On 22/06/2020 07:26:56-0700, Guenter Roeck wrote: > On Mon, Jun 22, 2020 at 12:14:13PM +0100, Lee Jones wrote: > > On Mon, 22 Jun 2020, Johnson CH Chen (陳昭勳) wrote: > > > > > Dallas/Maxim DS1374 is a counter designed to continuously count > > > time in seconds. It provides an I2C interface to the host to > > > access RTC clock or Alarm/Watchdog timer. > > > > > > Add MFD Core driver, supporting the I2C communication to RTC and > > > Watchdog devices. > > > > > > Signed-off-by: Johnson Chen <johnsonch.chen@xxxxxxxx> > > > --- > > > drivers/mfd/Kconfig | 11 +++++ > > > drivers/mfd/Makefile | 2 + > > > drivers/mfd/ds1374.c | 101 +++++++++++++++++++++++++++++++++++++++++++ > > > 3 files changed, 114 insertions(+) > > > create mode 100644 drivers/mfd/ds1374.c > > > > Not sure I see the point of this driver. > > > > Not entirely sure either. Seems to me the idea is to use the watchdog > subsystem for watchdog functionality, but that is just a guess and not > really necessary (the conversion could be done in the rtc driver). > I don't think the code as written works - the rtc code uses a mutex > which the watchdog driver obviously isn't aware of. The mutex would > have to be moved into the mfd code, with respective access functions. > > Overall this adds a lot of complexity, and it seems the interdependencies > between rtc and watchdog functionality are not well understood. Plus, > other watchdog drivers have recently been added to other rtc clock chips, > so this adds some inconsistencies in the rtc subsystem. Are we going > to see this change for all those combined rtc/watchdog drivers ? > If so, it might make sense to communicate that now to ensure consistency. > I read the datasheet again and I agree the watchdog part can live in the rtc driver. As only the RTC alarm and the watchdog are mutually exclusive. I don't think an MFD driver is necessary. Converting the current driver to the watchdog subsystem seems to be the correct way forward. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
