Re: [PATCH/RFC 1/5] dt-bindings: mfd: bd9571mwv: Document rohm,ddr-backup-power

Lee Jones
2017-10-13T10:00:16Z

On Fri, 13 Oct 2017, Geert Uytterhoeven wrote:

> Hi Lee,
>
> On Fri, Oct 13, 2017 at 10:55 AM, Lee Jones <lee.jones@linaro.org> wrote:
> > On Tue, 10 Oct 2017, Geert Uytterhoeven wrote:
> >> Document the new optional "rohm,ddr-backup-power" property.
> >>
> >> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> >> ---
> >> Documentation/devicetree/bindings/mfd/bd9571mwv.txt | 7 +++++++
> >> 1 file changed, 7 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/mfd/bd9571mwv.txt b/Documentation/devicetree/bindings/mfd/bd9571mwv.txt
> >> index 9ab216a851d5619b..7ea3f2db41d4e501 100644
> >> --- a/Documentation/devicetree/bindings/mfd/bd9571mwv.txt
> >> +++ b/Documentation/devicetree/bindings/mfd/bd9571mwv.txt
> >> @@ -25,6 +25,12 @@ Required properties:
> >> Each child node is defined using the standard
> >> binding for regulators.
> >>
> >> +Optional properties:
> >> + - rohm,ddr-backup-power : Value to use for DDR-Backup Power. This controls
> >> + which DDR rails need to be kept powered when backup
> >> + mode is enabled, cfr. the KEEPON_DDR* bits in the
> >
> > Perhaps it's just me, but I'm confused by this line.
> >
> > Can you word it another way?
>
> I'll ttry... Let me think a bit about it...

I think it's just the "cfr" which is throwing me.

> >> + documentation for the "BKUP Mode Cnt" register.
> >> +
> >> Example:
> >>
> >> pmic: pmic@30 {
> >> @@ -36,6 +42,7 @@ Example:
> >> #interrupt-cells = <2>;
> >> gpio-controller;
> >> #gpio-cells = <2>;
> >> + rohm,ddr-backup-power = <15>;
> >
> > Can you explain what this means? Is it a mask, or does line 15 need
> > to be kept on? What is the range? Is 0 acceptable? Clarification
> > required please.
>
> It's a mask (OR of (in this case all four) needed KEEPON_DDR* bits).
> Unfortunately the datasheet is not publicly available.
>
> 0 is acceptable, but as the property is optional, you better just leave it out.

Would you mind reflecting that in the doc please?

Maybe a few more examples will help?

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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