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

Geert Uytterhoeven
2017-10-13T09:02:56Z

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...

>> + 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.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds