[PATCH v2 1/4] leds: lp50xx: add setting of default intensity from DT

[PATCH v2 1/4] leds: lp50xx: add setting of default intensity from DT

[Sven Schuchmann]

In order to use a multicolor-led together with a trigger
the led needs to have an intensity set to see something.
The trigger changes the brightness of the led but if there
is no intensity we actually see nothing.

This patch adds the ability to set the default intensity
of each multi-led node so that it is turned on from DT.
If no intensity is given the led will be initialized
with full intensity.

Part 1 updates the documentation.
Part 2 removes an unused variable.
Part 3 sets the initial intensity to full.
Part 4 reads the default intensity from DT

changes in v1
 - fix dt_binding_check errors

changes in v2
 - sets default intensity to full
 - adds the property to the multi-led node

Signed-off-by: Sven Schuchmann <schuchmann@schleissheimer.de>
---
 Documentation/devicetree/bindings/leds/leds-lp50xx.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml b/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
index c192b5feadc7..2bc25b2fc94d 100644
--- a/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
+++ b/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
@@ -65,6 +65,11 @@ patternProperties:
           This property denotes the LED module number(s) that is used on the
           for the child node.  The LED modules can either be used stand alone
           or grouped into a module bank.
+      default-intensity:
+        minItems: 1
+        maxItems: 3
+        description:
+          The default intensity the multi-led gets initialised with.
 
     patternProperties:
       "(^led-[0-9a-f]$|led)":
@@ -99,6 +104,7 @@ examples:
                reg = <0x1>;
                color = <LED_COLOR_ID_RGB>;
                function = LED_FUNCTION_CHARGING;
+               default-intensity = <100 0 0>;
 
                led-0 {
                    color = <LED_COLOR_ID_RED>;
-- 
2.17.1

Re: [PATCH v2 1/4] leds: lp50xx: add setting of default intensity from DT

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 1982 bytes --]

Hi!

> In order to use a multicolor-led together with a trigger
> the led needs to have an intensity set to see something.
> The trigger changes the brightness of the led but if there
> is no intensity we actually see nothing.
> 
> This patch adds the ability to set the default intensity
> of each multi-led node so that it is turned on from DT.
> If no intensity is given the led will be initialized
> with full intensity.
> 
> Part 1 updates the documentation.
> Part 2 removes an unused variable.
> Part 3 sets the initial intensity to full.
> Part 4 reads the default intensity from DT
> 

> diff --git a/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml b/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
> index c192b5feadc7..2bc25b2fc94d 100644
> --- a/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
> +++ b/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
> @@ -65,6 +65,11 @@ patternProperties:
>            This property denotes the LED module number(s) that is used on the
>            for the child node.  The LED modules can either be used stand alone
>            or grouped into a module bank.
> +      default-intensity:
> +        minItems: 1
> +        maxItems: 3
> +        description:

Do we need more than three for RGBW and similar?

> +          The default intensity the multi-led gets initialised with.
>  
>      patternProperties:
>        "(^led-[0-9a-f]$|led)":
> @@ -99,6 +104,7 @@ examples:
>                 reg = <0x1>;
>                 color = <LED_COLOR_ID_RGB>;
>                 function = LED_FUNCTION_CHARGING;
> +               default-intensity = <100 0 0>;
>  
>                 led-0 {
>                     color = <LED_COLOR_ID_RED>;

Should this go to leds-class-multicolor.yaml ? Can you make example
<255 120 0> or something like that, so make it clear it is not
percent?

Best regards,
								Pavel

-- 
http://www.livejournal.com/~pavelmachek

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]

AW: [PATCH v2 1/4] leds: lp50xx: add setting of default intensity from DT

[Sven Schuchmann]

Hello Pavel, hello Dan,

> > diff --git a/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml b/Documentation/devicetree/bindings/leds/leds-
> lp50xx.yaml
> > index c192b5feadc7..2bc25b2fc94d 100644
> > --- a/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
> > +++ b/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
> > @@ -65,6 +65,11 @@ patternProperties:
> >            This property denotes the LED module number(s) that is used on the
> >            for the child node.  The LED modules can either be used stand alone
> >            or grouped into a module bank.
> > +      default-intensity:
> > +        minItems: 1
> > +        maxItems: 3
> > +        description:
> 
> Do we need more than three for RGBW and similar?

AFAIK the lp50xx supports only RGB. So I would go for that.


> >      patternProperties:
> >        "(^led-[0-9a-f]$|led)":
> > @@ -99,6 +104,7 @@ examples:
> >                 reg = <0x1>;
> >                 color = <LED_COLOR_ID_RGB>;
> >                 function = LED_FUNCTION_CHARGING;
> > +               default-intensity = <100 0 0>;
> >
> >                 led-0 {
> >                     color = <LED_COLOR_ID_RED>;
> 
> Should this go to leds-class-multicolor.yaml ? 

I think then all drivers should support it,  but I cannot change all drivers. 
So I would only leave it in there.


> Can you make example
> <255 120 0> or something like that, so make it clear it is not
> percent?

Sure

Best Regards,

   Sven

Re: [PATCH v2 1/4] leds: lp50xx: add setting of default intensity from DT

[Pavel Machek]

[-- Attachment #1: Type: text/plain, Size: 822 bytes --]

Hi!

> > >      patternProperties:
> > >        "(^led-[0-9a-f]$|led)":
> > > @@ -99,6 +104,7 @@ examples:
> > >                 reg = <0x1>;
> > >                 color = <LED_COLOR_ID_RGB>;
> > >                 function = LED_FUNCTION_CHARGING;
> > > +               default-intensity = <100 0 0>;
> > >
> > >                 led-0 {
> > >                     color = <LED_COLOR_ID_RED>;
> > 
> > Should this go to leds-class-multicolor.yaml ? 
> 
> I think then all drivers should support it,  but I cannot change all drivers. 
> So I would only leave it in there.

It really should be in common binding, and no, that does not mean you
need to change all the drivers.

Plus there's at most two of them at the moment.

Best regards,
							Pavel

-- 
http://www.livejournal.com/~pavelmachek

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 181 bytes --]

Re: [PATCH v2 1/4] leds: lp50xx: add setting of default intensity from DT

[Jacek Anaszewski]

Hi Pavel,

On 2/5/21 11:23 AM, Pavel Machek wrote:
> Hi!
> 
>>>>       patternProperties:
>>>>         "(^led-[0-9a-f]$|led)":
>>>> @@ -99,6 +104,7 @@ examples:
>>>>                  reg = <0x1>;
>>>>                  color = <LED_COLOR_ID_RGB>;
>>>>                  function = LED_FUNCTION_CHARGING;
>>>> +               default-intensity = <100 0 0>;

How will you know which array position is for which child LED?
I presume DT child nodes are not guaranteed to be parsed in the order
of declaration?

>>>>
>>>>                  led-0 {
>>>>                      color = <LED_COLOR_ID_RED>;
>>>
>>> Should this go to leds-class-multicolor.yaml ?
>>
>> I think then all drivers should support it,  but I cannot change all drivers.
>> So I would only leave it in there.
> 
> It really should be in common binding, and no, that does not mean you
> need to change all the drivers.
> 
> Plus there's at most two of them at the moment.
> 
> Best regards,
> 							Pavel
> 

-- 
Best regards,
Jacek Anaszewski

AW: [PATCH v2 1/4] leds: lp50xx: add setting of default intensity from DT

[Sven Schuchmann]

Hello Dan,

> Von: Jacek Anaszewski <jacek.anaszewski@gmail.com>
> Gesendet: Freitag, 5. Februar 2021 19:37
> Hi Pavel,
> 
> On 2/5/21 11:23 AM, Pavel Machek wrote:
> > Hi!
> >
> >>>>       patternProperties:
> >>>>         "(^led-[0-9a-f]$|led)":
> >>>> @@ -99,6 +104,7 @@ examples:
> >>>>                  reg = <0x1>;
> >>>>                  color = <LED_COLOR_ID_RGB>;
> >>>>                  function = LED_FUNCTION_CHARGING;
> >>>> +               default-intensity = <100 0 0>;
> 
> How will you know which array position is for which child LED?
> I presume DT child nodes are not guaranteed to be parsed in the order
> of declaration?

I tried to fiddle this out, but it seems Jacek is right over here.
The multi-led definition looks like this (from the documentation leds-lp50xx.yaml)

        multi-led@1 {
               #address-cells = <1>;
               #size-cells = <0>;
               reg = <0x1>;
               color = <LED_COLOR_ID_RGB>;
               function = LED_FUNCTION_CHARGING;

               led-0 {
                   color = <LED_COLOR_ID_RED>;
               };

               led-1 {
                   color = <LED_COLOR_ID_GREEN>;
               };

               led-2 {
                   color = <LED_COLOR_ID_BLUE>;
               };
          };

But it seems that the color definition of each led is ignored.
By ignored I mean the driver does not take care which color
is at which position. So if I change led-0 to be LED_COLOR_ID_BLUE
and led-2 to be LED_COLOR_ID_RED nothing will change if I write
from userspace. Could you help to clarify?
Then it is even hard to know which led to set with default-intensity.

Also it seems that the enumeration of the multi-leds should
start with multi-led@0 (and not 1 as in the documentation).

Best Regards,

   Sven

Re: AW: [PATCH v2 1/4] leds: lp50xx: add setting of default intensity from DT

[Jacek Anaszewski]

Sven,

On 2/6/21 2:14 PM, Sven Schuchmann wrote:
> Hello Dan,
> 
>> Von: Jacek Anaszewski <jacek.anaszewski@gmail.com>
>> Gesendet: Freitag, 5. Februar 2021 19:37
>> Hi Pavel,
>>
>> On 2/5/21 11:23 AM, Pavel Machek wrote:
>>> Hi!
>>>
>>>>>>        patternProperties:
>>>>>>          "(^led-[0-9a-f]$|led)":
>>>>>> @@ -99,6 +104,7 @@ examples:
>>>>>>                   reg = <0x1>;
>>>>>>                   color = <LED_COLOR_ID_RGB>;
>>>>>>                   function = LED_FUNCTION_CHARGING;
>>>>>> +               default-intensity = <100 0 0>;
>>
>> How will you know which array position is for which child LED?
>> I presume DT child nodes are not guaranteed to be parsed in the order
>> of declaration?
> 
> I tried to fiddle this out, but it seems Jacek is right over here.
> The multi-led definition looks like this (from the documentation leds-lp50xx.yaml)
> 
>          multi-led@1 {
>                 #address-cells = <1>;
>                 #size-cells = <0>;
>                 reg = <0x1>;
>                 color = <LED_COLOR_ID_RGB>;
>                 function = LED_FUNCTION_CHARGING;
> 
>                 led-0 {
>                     color = <LED_COLOR_ID_RED>;
>                 };
> 
>                 led-1 {
>                     color = <LED_COLOR_ID_GREEN>;
>                 };
> 
>                 led-2 {
>                     color = <LED_COLOR_ID_BLUE>;
>                 };
>            };
> 
> But it seems that the color definition of each led is ignored.
> By ignored I mean the driver does not take care which color
> is at which position. So if I change led-0 to be LED_COLOR_ID_BLUE
> and led-2 to be LED_COLOR_ID_RED nothing will change if I write
> from userspace. Could you help to clarify?
> Then it is even hard to know which led to set with default-intensity.

See Documentation/ABI/testing/sysfs-class-led-multicolor and
documentation of multi_index and multi_intensity files.
It is the multi_index file that tells what is the order of colors
in the multi_intensity file.

And that depends on the order of enumeration of the nodes by DT parser.

> Also it seems that the enumeration of the multi-leds should
> start with multi-led@0 (and not 1 as in the documentation).

The @unit-address part of node name must match the first address
specified in the reg property of the node, so this is correct.
-- 
Best regards,
Jacek Anaszewski