Re: [PATCH 2/2] doc: dt: add documentation for alphascale,asm9260-rtc

[Alexandre Belloni <alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>]

On 01/02/2016 at 09:27:50 -0600, Rob Herring wrote :
> On Fri, Jan 29, 2016 at 09:40:02AM +0100, Oleksij Rempel wrote:
> > Document Alphascale asm9260 RTC bindings
> > 
> > Signed-off-by: Oleksij Rempel <linux-YEK0n+YFykbzxQdaRaTXBw@public.gmane.org>
> > ---
> >  .../bindings/rtc/alphascale,asm9260-rtc.txt        | 25 ++++++++++++++++++++++
> >  1 file changed, 25 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/rtc/alphascale,asm9260-rtc.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/rtc/alphascale,asm9260-rtc.txt b/Documentation/devicetree/bindings/rtc/alphascale,asm9260-rtc.txt
> > new file mode 100644
> > index 0000000..2c0ff3c
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/rtc/alphascale,asm9260-rtc.txt
> > @@ -0,0 +1,25 @@
> > +* Alphascale asm9260 SoC Real Time Clock
> > +
> > +Required properties:
> > +- compatible: Should be "alphascale,asm9260-rtc"
> > +- reg: Physical base address of the controller and length
> > +       of memory mapped region.
> > +- interrupts: IRQ line for the RTC.
> > +- clocks: Reference to the clock entry.
> > +- clock-names: should contain:
> > +  * "ahb" for the SoC RTC clock
> > +
> > +Optional:
> > +- calibration: calibration value for 1 sec period.
> > +		Max value for forward calibration is 0x1ffff (131071),
> > +		Min value for backward calibration is 0xfffe0001 (-131071).
> 
> This should be prefixed with 'alphascale,'
> 
> How is this value determined?
> 

I think this should stay in userspace, see that series:
https://groups.google.com/forum/#!topic/rtc-linux/HGQqiHnMiuw

It quite often depends on environmental things like temperature so it may be updated at runtime.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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