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

Message ID 1507649178-31473-2-git-send-email-geert+renesas@glider.be
State Changes Requested
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Series
  • arm64: dts: renesas: Salvator-X/XS: Enable DDR Backup Mode
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Commit Message

Geert Uytterhoeven Oct. 10, 2017, 3:26 p.m.
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(+)

Comments

Lee Jones Oct. 13, 2017, 8:55 a.m. | #1
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?

> +			    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.

>  		regulators {
>  			dvfs: dvfs {
Geert Uytterhoeven Oct. 13, 2017, 9:02 a.m. | #2
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
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Lee Jones Oct. 13, 2017, 10 a.m. | #3
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?

Patch

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
+			    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>;
 
 		regulators {
 			dvfs: dvfs {