Hi Geert,
Happy St Patrick's Day!
(I know you are not Irish....but you are closer to Ireland than I am ;)
On Friday, March 17, 2017, Geert Uytterhoeven wrote:
> On Thu, Mar 16, 2017 at 6:51 PM, Chris Brandt <chris.brandt@xxxxxxxxxxx>
> wrote:
> > rtc-sh is a RTC for SuperH and RZ/A SoCs.
>
> an RTC?
Good point. That's more better ;)
> > +Required properties:
> > +- compatible: Should be "renesas,r7s72100-rtc" or "renesas,sh-rtc" as
> > +a
>
> s/or/and/
OK
> > + fallback.
> > +- reg: physical base address and length of memory mapped region.
> > +- interrupts: 3 interrupts for alarm, period, and carry.
>
> If there's a need for multiple interrupts, it's always a good idea to use
> interrupt-names. The datasheet calls them "arm", "prd", and "cup", but I
> wouldn't object against "alarm", "period", and "carry" ;-)
OK. I'll change.
I like the longer names as well ("prd" looks ugly)
> > +- clocks: the clock source for the RTC controller.
>
> The datasheet mentions 3 possible clock sources?
There is the clock source that does the counting (RTC_X1, RTC_X3, XTAL), and then a clock source that runs the register interface (run off of the p0 clock). So I just need to turn on the p0 clock so I can get at the registers. Note that if you do a hard reset with a RESET button, and all the registers in the chip go back to their POR state, the counter still counts off of the 32KHz XTAL even though the "peripheral clock" is stopped (which just means you can't get to the registers).
In reality, you have to assume the RTC counting source has already been set up by u-boot, or from a past reboot, so I don't do any of that select configuration at all.
Chris
