On Wed, Feb 12, 2025 at 02:35:32PM +0800, Peng Fan wrote: > On Tue, Feb 11, 2025 at 04:59:53PM +0000, Sudeep Holla wrote: > >On Tue, Jan 21, 2025 at 02:31:55PM +0000, Peng Fan wrote: > >> > >> It is the i.MX SCMI Protocol exports two RTCs using one protocol. > >> > >> Two RTC devices are created, but share one parent device. > >> > >> Do you mean each RTC device should have a unique parent device? > >> > > > >Can you point where is this check for unique parent ? I am not so familiar > >with RTC but I couldn't find myself with quick search. > > The RTC ops takes the rtc parent as input parameter > https://elixir.bootlin.com/linux/v6.13.2/source/drivers/rtc/interface.c#L94 > "err = rtc->ops->read_time(rtc->dev.parent, tm);" > > So in the rtc device driver, there is no way to know which rtc it is just > from the parent device. > If that is the expectation, you could create a platform or normal device per instance of RTC on your platform and slap them as parent device. IIUC on any pure DT based system, a device node exists per RTC and hence platform device associated with it. And the RTC devices are created with parent pointing to unique platform device. > However i.MX SCMI BBM exports two RTCs(id: 0, id: 1), so to make it work for > current RTC framework, we could only pick one RTC and pass the id to BBM > server side. > > I am not sure whether Alexandre wanna me to update the code following each > parent could only support one RTC or else. > I assume something like my suggestion above. -- Regards, Sudeep
