On 02/02/2023 16:12:33+0100, Johan Hovold wrote: > On Fri, Jan 27, 2023 at 05:05:03PM +0100, Alexandre Belloni wrote: > > On 27/01/2023 16:51:27+0100, Johan Hovold wrote: > > > > > > @@ -380,9 +478,23 @@ static int pm8xxx_rtc_probe(struct platform_device *pdev) > > > > > rtc_dd->allow_set_time = of_property_read_bool(pdev->dev.of_node, > > > > > "allow-set-time"); > > > > > > > > > > + rtc_dd->nvmem_cell = devm_nvmem_cell_get(&pdev->dev, "offset"); > > > > > > > > Maybe we should get something more specific than just "offset" so this > > > > could be parsed in the RTC core at some point (this is the second RTC to > > > > behave like this) > > > > > > Yes, that thought crossed my mind, but it's an nvmem cell name (label) > > > and not a generic devicetree property. If you look at the binding > > > document I think the name makes sense given the current description, and > > > I'm not sure changing to something like 'base' would be much of an > > > improvement. > > > > > > I also don't expect there to be more broken RTCs out there like these > > > ones. Hopefully Qualcomm will even get this fixed at some point > > > themselves. > > > > > > And I assume you were think of the old Atmel driver which uses a timer > > > counter and a scratch register as a base? That one is also a bit > > > different in that the timer can be reset, just not set. > > > > Nope, I'm thinking about the gamecube one and probably the nintendo > > switch one which seems to behave similarly (no driver in the kernel > > though). > > Found the gamecube one now (misread you comment above to imply that it > was also out of tree). > > That one is also different in that the timer in that RTC can also be > set (e.g. like the atmel one), but for consistency with some firmware an > offset also needs to be read from SRAM (not NVRAM) and applied. That > offset is also never updated by Linux. Yeah, I deally, the gamecube counter shouldn't be updated, the switch one doesn't seem to be updatable. I guess the idea being that games need to be able to know if you are messing with the RTC to get an advantage. -- Alexandre Belloni, co-owner and COO, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
