Initial multicolor LED intensities

Initial multicolor LED intensities

[Sven Schwermer]

Hi,

Is there a way to assign initial (non-zero) intensities to the 
individual colors of a multicolor LED via the device tree?

In my use case, I'd like to assign a default trigger to a multicolor LED 
(e.g. linux,default-trigger="heartbeat"). However, since the color 
intensities are zero upon boot, I don't get a heartbeat on the 
multicolor LED.

Best regards,
Sven

Re: Initial multicolor LED intensities

[Pavel Machek]

Hi!

> Is there a way to assign initial (non-zero) intensities to the individual
> colors of a multicolor LED via the device tree?

I don't believe we have such functionality. Patch would be welcome.

> In my use case, I'd like to assign a default trigger to a multicolor LED
> (e.g. linux,default-trigger="heartbeat"). However, since the color
> intensities are zero upon boot, I don't get a heartbeat on the multicolor
> LED.

Hmm. Defaulting to zero does not really make much sense. I guess we
should default to full on all channels?

Best regards,
								Pavel

[PATCH v1 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Sven Schwermer]

From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>

This allows to assign intensity values to the indivisual sub LEDs
(colors) at driver probe time, i.e. most commonly at kernel boot time.
This is crucial for setting a specific color early in the boot process.

Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
---
 .../devicetree/bindings/leds/leds-class-multicolor.yaml    | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
index 37445c68cdef..c483967a847c 100644
--- a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
+++ b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
@@ -31,6 +31,13 @@ patternProperties:
           include/linux/leds/common.h.
         enum: [ 8, 9 ]
 
+      default-intensities:
+        description: |
+          This parameter, if present, sets the initial intensities of the
+          individual colors. This array must have the same length as the
+          multi-color LED has sub LEDs (colors).
+        $ref: /schemas/types.yaml#/definitions/uint32-array
+
     $ref: "common.yaml#"
 
     required:
-- 
2.36.0

[PATCH v1 2/2] leds: multicolor: Read default-intensities property

[Sven Schwermer]

From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>

This allows to assign intensity values taken from the firmware interface
(if available) to the indivisual sub LEDs (colors) at driver probe time,
i.e. most commonly at kernel boot time. This is crucial for setting a
specific color and early in the boot process. While it would be possible
to set a static color in the bootloader, this mechanism allows setting a
pattern (e.g. blinking) at a specific color.

Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
---
 drivers/leds/led-class-multicolor.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/leds/led-class-multicolor.c b/drivers/leds/led-class-multicolor.c
index e317408583df..eb7f11345ec1 100644
--- a/drivers/leds/led-class-multicolor.c
+++ b/drivers/leds/led-class-multicolor.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
+#include <linux/property.h>
 
 #include "leds.h"
 
@@ -116,6 +117,23 @@ static struct attribute *led_multicolor_attrs[] = {
 };
 ATTRIBUTE_GROUPS(led_multicolor);
 
+static void multi_load_default_intensities(struct device *parent,
+					   struct led_classdev_mc *mcled_cdev,
+					   struct fwnode_handle *fwnode)
+{
+	u32 intensities[LED_COLOR_ID_MAX];
+	int ret;
+	int i;
+
+	ret = fwnode_property_read_u32_array(fwnode, "default-intensities",
+					     intensities, mcled_cdev->num_colors);
+	if (ret < 0 && ret != -ENODATA)
+		dev_warn(parent, "failed to read default-intensities property: %d", ret);
+
+	for (i = 0; i < ret; i++)
+		mcled_cdev->subled_info[i].intensity = intensities[i];
+}
+
 int led_classdev_multicolor_register_ext(struct device *parent,
 				     struct led_classdev_mc *mcled_cdev,
 				     struct led_init_data *init_data)
@@ -134,6 +152,9 @@ int led_classdev_multicolor_register_ext(struct device *parent,
 	led_cdev = &mcled_cdev->led_cdev;
 	mcled_cdev->led_cdev.groups = led_multicolor_groups;
 
+	if (init_data && init_data->fwnode)
+		multi_load_default_intensities(parent, mcled_cdev, init_data->fwnode);
+
 	return led_classdev_register_ext(parent, led_cdev, init_data);
 }
 EXPORT_SYMBOL_GPL(led_classdev_multicolor_register_ext);
-- 
2.36.0

[PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Sven Schwermer]

From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>

This allows to assign intensity values to the indivisual sub LEDs
(colors) at driver probe time, i.e. most commonly at kernel boot time.
This is crucial for setting a specific color early in the boot process.

Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
---

Notes:
    V1->V2: no changes

 .../devicetree/bindings/leds/leds-class-multicolor.yaml    | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
index 37445c68cdef..c483967a847c 100644
--- a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
+++ b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
@@ -31,6 +31,13 @@ patternProperties:
           include/linux/leds/common.h.
         enum: [ 8, 9 ]
 
+      default-intensities:
+        description: |
+          This parameter, if present, sets the initial intensities of the
+          individual colors. This array must have the same length as the
+          multi-color LED has sub LEDs (colors).
+        $ref: /schemas/types.yaml#/definitions/uint32-array
+
     $ref: "common.yaml#"
 
     required:
-- 
2.36.0

[PATCH v2 2/2] leds: multicolor: Read default-intensities property

[Sven Schwermer]

From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>

This allows to assign intensity values taken from the firmware interface
(if available) to the indivisual sub LEDs (colors) at driver probe time,
i.e. most commonly at kernel boot time. This is crucial for setting a
specific color and early in the boot process. While it would be possible
to set a static color in the bootloader, this mechanism allows setting a
pattern (e.g. blinking) at a specific color.

Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
---

Notes:
    V1->V2: Fix mixup

 drivers/leds/led-class-multicolor.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/drivers/leds/led-class-multicolor.c b/drivers/leds/led-class-multicolor.c
index e317408583df..84f237784246 100644
--- a/drivers/leds/led-class-multicolor.c
+++ b/drivers/leds/led-class-multicolor.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
+#include <linux/property.h>
 
 #include "leds.h"
 
@@ -116,6 +117,26 @@ static struct attribute *led_multicolor_attrs[] = {
 };
 ATTRIBUTE_GROUPS(led_multicolor);
 
+static void multi_load_default_intensities(struct device *parent,
+					   struct led_classdev_mc *mcled_cdev,
+					   struct fwnode_handle *fwnode)
+{
+	u32 intensities[LED_COLOR_ID_MAX];
+	unsigned int i;
+	int ret;
+
+	ret = fwnode_property_read_u32_array(fwnode, "default-intensities",
+					     intensities, mcled_cdev->num_colors);
+	if (ret < 0) {
+		if (ret != -ENODATA)
+			dev_warn(parent, "failed to read default-intensities property: %d", ret);
+		return;
+	}
+
+	for (i = 0; i < mcled_cdev->num_colors; i++)
+		mcled_cdev->subled_info[i].intensity = intensities[i];
+}
+
 int led_classdev_multicolor_register_ext(struct device *parent,
 				     struct led_classdev_mc *mcled_cdev,
 				     struct led_init_data *init_data)
@@ -134,6 +155,9 @@ int led_classdev_multicolor_register_ext(struct device *parent,
 	led_cdev = &mcled_cdev->led_cdev;
 	mcled_cdev->led_cdev.groups = led_multicolor_groups;
 
+	if (init_data && init_data->fwnode)
+		multi_load_default_intensities(parent, mcled_cdev, init_data->fwnode);
+
 	return led_classdev_register_ext(parent, led_cdev, init_data);
 }
 EXPORT_SYMBOL_GPL(led_classdev_multicolor_register_ext);
-- 
2.36.0

AW: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Sven Schuchmann]

Hello Sven,

tried this some time ago for the LP50XX
https://lore.kernel.org/all/20210204143726.27977-1-schuchmann@schleissheimer.de/

Your solution looks much better.
Could you give an example of how to use it?

My Configuration at this time looks like this:

multi-led@0 {
		#address-cells = <1>;
		#size-cells = <0>;
		reg = <0x0>;
		color = <LED_COLOR_ID_RGB>;
		function = "eee-led-status";

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

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

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


Where do I put the "default-intensities"?

Regards,

   Sven

> -----Ursprüngliche Nachricht-----
> Von: Sven Schwermer <sven@svenschwermer.de>
> Gesendet: Dienstag, 3. Mai 2022 13:27
> An: linux-leds@vger.kernel.org; linux-kernel@vger.kernel.org; pavel@ucw.cz;
> robh+dt@kernel.org; krzysztof.kozlowski+dt@linaro.org; dmurphy@ti.com;
> devicetree@vger.kernel.org
> Cc: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
> Betreff: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property
> 
> From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
> 
> This allows to assign intensity values to the indivisual sub LEDs
> (colors) at driver probe time, i.e. most commonly at kernel boot time.
> This is crucial for setting a specific color early in the boot process.
> 
> Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
> ---
> 
> Notes:
>     V1->V2: no changes
> 
>  .../devicetree/bindings/leds/leds-class-multicolor.yaml    | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
> b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
> index 37445c68cdef..c483967a847c 100644
> --- a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
> +++ b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
> @@ -31,6 +31,13 @@ patternProperties:
>            include/linux/leds/common.h.
>          enum: [ 8, 9 ]
> 
> +      default-intensities:
> +        description: |
> +          This parameter, if present, sets the initial intensities of the
> +          individual colors. This array must have the same length as the
> +          multi-color LED has sub LEDs (colors).
> +        $ref: /schemas/types.yaml#/definitions/uint32-array
> +
>      $ref: "common.yaml#"
> 
>      required:
> --
> 2.36.0

Re: AW: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Sven Schwermer]

Hi Sven,

Thanks for making me aware of your patch series. My series would work 
similar to yours, i.e. the default-intensities property would be on the 
same level as color = <LED_COLOR_ID_RGB>.

However, the concern voiced by Jacek is relevant for my patch as well, 
see 
https://lore.kernel.org/all/d5631e35-cd62-106f-2ec4-de3163367bc0@gmail.com/
However, I do not know how to resolve the issue. Perhaps somebody from 
the list has ideas?

Best regards,
Sven

On 5/3/22 15:50, Sven Schuchmann wrote:
> Hello Sven,
> 
> tried this some time ago for the LP50XX
> https://lore.kernel.org/all/20210204143726.27977-1-schuchmann@schleissheimer.de/
> 
> Your solution looks much better.
> Could you give an example of how to use it?
> 
> My Configuration at this time looks like this:
> 
> multi-led@0 {
> 		#address-cells = <1>;
> 		#size-cells = <0>;
> 		reg = <0x0>;
> 		color = <LED_COLOR_ID_RGB>;
> 		function = "eee-led-status";
> 
> 		led-0 {
> 			color = <LED_COLOR_ID_RED>;
> 		};
> 
> 		led-1 {
> 			color = <LED_COLOR_ID_GREEN>;
> 		};
> 
> 		led-2 {
> 			color = <LED_COLOR_ID_BLUE>;
> 		};
> 	};
> 
> 
> Where do I put the "default-intensities"?
> 
> Regards,
> 
>     Sven
> 
>> -----Ursprüngliche Nachricht-----
>> Von: Sven Schwermer <sven@svenschwermer.de>
>> Gesendet: Dienstag, 3. Mai 2022 13:27
>> An: linux-leds@vger.kernel.org; linux-kernel@vger.kernel.org; pavel@ucw.cz;
>> robh+dt@kernel.org; krzysztof.kozlowski+dt@linaro.org; dmurphy@ti.com;
>> devicetree@vger.kernel.org
>> Cc: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
>> Betreff: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property
>>
>> From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
>>
>> This allows to assign intensity values to the indivisual sub LEDs
>> (colors) at driver probe time, i.e. most commonly at kernel boot time.
>> This is crucial for setting a specific color early in the boot process.
>>
>> Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
>> ---
>>
>> Notes:
>>      V1->V2: no changes
>>
>>   .../devicetree/bindings/leds/leds-class-multicolor.yaml    | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
>> b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
>> index 37445c68cdef..c483967a847c 100644
>> --- a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
>> +++ b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
>> @@ -31,6 +31,13 @@ patternProperties:
>>             include/linux/leds/common.h.
>>           enum: [ 8, 9 ]
>>
>> +      default-intensities:
>> +        description: |
>> +          This parameter, if present, sets the initial intensities of the
>> +          individual colors. This array must have the same length as the
>> +          multi-color LED has sub LEDs (colors).
>> +        $ref: /schemas/types.yaml#/definitions/uint32-array
>> +
>>       $ref: "common.yaml#"
>>
>>       required:
>> --
>> 2.36.0
> 

AW: AW: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Sven Schuchmann]

Hello Sven,


> -----Ursprüngliche Nachricht-----
> Von: Sven Schwermer <sven@svenschwermer.de>
> Gesendet: Dienstag, 3. Mai 2022 20:59
> An: Sven Schuchmann <schuchmann@schleissheimer.de>; linux-leds@vger.kernel.org
> Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>; pavel@ucw.cz
> Betreff: Re: AW: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities
> property
> 
> Hi Sven,
> 
> Thanks for making me aware of your patch series. My series would work
> similar to yours, i.e. the default-intensities property would be on the
> same level as color = <LED_COLOR_ID_RGB>.
> 
> However, the concern voiced by Jacek is relevant for my patch as well,
> see
> https://lore.kernel.org/all/d5631e35-cd62-106f-2ec4-de3163367bc0@gmail.com/
> However, I do not know how to resolve the issue. Perhaps somebody from
> the list has ideas?

I also do not have an idea. But maybe we can talk about how the definition 
should look like in DT. As far as I understood with your patch I would 
have define the LED as follows:

multi-led@0 {
	#address-cells = <1>;
	#size-cells = <0>;
	reg = <0x0>;
	color = <LED_COLOR_ID_RGB>;
	default-intensities = <100 0 0>  <----
	function = "eee-led-status";
	led-0 {
		color = <LED_COLOR_ID_RED>;
	};
	led-1 {
		color = <LED_COLOR_ID_GREEN>;
	};
	led-2 {
		color = <LED_COLOR_ID_BLUE>;
	};
};


Maybe it is better to define per Color like this:

multi-led@0 {
	#address-cells = <1>;
	#size-cells = <0>;
	reg = <0x0>;
	color = <LED_COLOR_ID_RGB>;
	function = "eee-led-status";
	led-0 {
		color = <LED_COLOR_ID_RED>;
		default-intensity = 100
	};
	led-1 {
		color = <LED_COLOR_ID_GREEN>;
		default-intensity = 0
	};
	led-2 {
		color = <LED_COLOR_ID_BLUE>;
		default-intensity = 0
	};
};


I think this could then be handled by RGBW LEDs also.

Best Regards,

   Sven



> 
> Best regards,
> Sven
> 
> On 5/3/22 15:50, Sven Schuchmann wrote:
> > Hello Sven,
> >
> > tried this some time ago for the LP50XX
> > https://lore.kernel.org/all/20210204143726.27977-1-schuchmann@schleissheimer.de/
> >
> > Your solution looks much better.
> > Could you give an example of how to use it?
> >
> > My Configuration at this time looks like this:
> >
> > multi-led@0 {
> > 		#address-cells = <1>;
> > 		#size-cells = <0>;
> > 		reg = <0x0>;
> > 		color = <LED_COLOR_ID_RGB>;
> > 		function = "eee-led-status";
> >
> > 		led-0 {
> > 			color = <LED_COLOR_ID_RED>;
> > 		};
> >
> > 		led-1 {
> > 			color = <LED_COLOR_ID_GREEN>;
> > 		};
> >
> > 		led-2 {
> > 			color = <LED_COLOR_ID_BLUE>;
> > 		};
> > 	};
> >
> >
> > Where do I put the "default-intensities"?
> >
> > Regards,
> >
> >     Sven
> >
> >> -----Ursprüngliche Nachricht-----
> >> Von: Sven Schwermer <sven@svenschwermer.de>
> >> Gesendet: Dienstag, 3. Mai 2022 13:27
> >> An: linux-leds@vger.kernel.org; linux-kernel@vger.kernel.org; pavel@ucw.cz;
> >> robh+dt@kernel.org; krzysztof.kozlowski+dt@linaro.org; dmurphy@ti.com;
> >> devicetree@vger.kernel.org
> >> Cc: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
> >> Betreff: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property
> >>
> >> From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
> >>
> >> This allows to assign intensity values to the indivisual sub LEDs
> >> (colors) at driver probe time, i.e. most commonly at kernel boot time.
> >> This is crucial for setting a specific color early in the boot process.
> >>
> >> Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
> >> ---
> >>
> >> Notes:
> >>      V1->V2: no changes
> >>
> >>   .../devicetree/bindings/leds/leds-class-multicolor.yaml    | 7 +++++++
> >>   1 file changed, 7 insertions(+)
> >>
> >> diff --git a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
> >> b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
> >> index 37445c68cdef..c483967a847c 100644
> >> --- a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
> >> +++ b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
> >> @@ -31,6 +31,13 @@ patternProperties:
> >>             include/linux/leds/common.h.
> >>           enum: [ 8, 9 ]
> >>
> >> +      default-intensities:
> >> +        description: |
> >> +          This parameter, if present, sets the initial intensities of the
> >> +          individual colors. This array must have the same length as the
> >> +          multi-color LED has sub LEDs (colors).
> >> +        $ref: /schemas/types.yaml#/definitions/uint32-array
> >> +
> >>       $ref: "common.yaml#"
> >>
> >>       required:
> >> --
> >> 2.36.0
> >

Re: AW: AW: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Sven Schwermer]

Hi Sven,

I did consider placing the property into the multicolor's sub nodes. 
However, multicolor LEDs are not required to have firmware sub nodes. At 
least the multicolor class API does not make any assumptions about this.

One possible solution that I came up with is to do something like this:

multi-led {
	color = <LED_COLOR_ID_RGB>;
	default-intensities = <
		LED_COLOR_ID_RED 100
		LED_COLOR_ID_GREEN 0
		LED_COLOR_ID_BLUE 0
	>;
	led-0 {
		color = <LED_COLOR_ID_RED>;
	};
	led-1 {
		color = <LED_COLOR_ID_GREEN>;
	};
	led-2 {
		color = <LED_COLOR_ID_BLUE>;
	};
};

This requires the array to be twice as long as the number of colors (sub 
LEDs). Each color identifier would be paired with the initial intensity. 
This would limit number of LEDs per color to 1. However, I believe, this 
limitation is already there today.

Thoughts?

Best regards,
Sven

On 5/4/22 09:17, Sven Schuchmann wrote:
> Hello Sven,
> 
> 
>> -----Ursprüngliche Nachricht-----
>> Von: Sven Schwermer <sven@svenschwermer.de>
>> Gesendet: Dienstag, 3. Mai 2022 20:59
>> An: Sven Schuchmann <schuchmann@schleissheimer.de>; linux-leds@vger.kernel.org
>> Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>; pavel@ucw.cz
>> Betreff: Re: AW: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities
>> property
>>
>> Hi Sven,
>>
>> Thanks for making me aware of your patch series. My series would work
>> similar to yours, i.e. the default-intensities property would be on the
>> same level as color = <LED_COLOR_ID_RGB>.
>>
>> However, the concern voiced by Jacek is relevant for my patch as well,
>> see
>> https://lore.kernel.org/all/d5631e35-cd62-106f-2ec4-de3163367bc0@gmail.com/
>> However, I do not know how to resolve the issue. Perhaps somebody from
>> the list has ideas?
> 
> I also do not have an idea. But maybe we can talk about how the definition
> should look like in DT. As far as I understood with your patch I would
> have define the LED as follows:
> 
> multi-led@0 {
> 	#address-cells = <1>;
> 	#size-cells = <0>;
> 	reg = <0x0>;
> 	color = <LED_COLOR_ID_RGB>;
> 	default-intensities = <100 0 0>  <----
> 	function = "eee-led-status";
> 	led-0 {
> 		color = <LED_COLOR_ID_RED>;
> 	};
> 	led-1 {
> 		color = <LED_COLOR_ID_GREEN>;
> 	};
> 	led-2 {
> 		color = <LED_COLOR_ID_BLUE>;
> 	};
> };
> 
> 
> Maybe it is better to define per Color like this:
> 
> multi-led@0 {
> 	#address-cells = <1>;
> 	#size-cells = <0>;
> 	reg = <0x0>;
> 	color = <LED_COLOR_ID_RGB>;
> 	function = "eee-led-status";
> 	led-0 {
> 		color = <LED_COLOR_ID_RED>;
> 		default-intensity = 100
> 	};
> 	led-1 {
> 		color = <LED_COLOR_ID_GREEN>;
> 		default-intensity = 0
> 	};
> 	led-2 {
> 		color = <LED_COLOR_ID_BLUE>;
> 		default-intensity = 0
> 	};
> };
> 
> 
> I think this could then be handled by RGBW LEDs also.
> 
> Best Regards,
> 
>     Sven
> 
> 
> 
>>
>> Best regards,
>> Sven
>>
>> On 5/3/22 15:50, Sven Schuchmann wrote:
>>> Hello Sven,
>>>
>>> tried this some time ago for the LP50XX
>>> https://lore.kernel.org/all/20210204143726.27977-1-schuchmann@schleissheimer.de/
>>>
>>> Your solution looks much better.
>>> Could you give an example of how to use it?
>>>
>>> My Configuration at this time looks like this:
>>>
>>> multi-led@0 {
>>> 		#address-cells = <1>;
>>> 		#size-cells = <0>;
>>> 		reg = <0x0>;
>>> 		color = <LED_COLOR_ID_RGB>;
>>> 		function = "eee-led-status";
>>>
>>> 		led-0 {
>>> 			color = <LED_COLOR_ID_RED>;
>>> 		};
>>>
>>> 		led-1 {
>>> 			color = <LED_COLOR_ID_GREEN>;
>>> 		};
>>>
>>> 		led-2 {
>>> 			color = <LED_COLOR_ID_BLUE>;
>>> 		};
>>> 	};
>>>
>>>
>>> Where do I put the "default-intensities"?
>>>
>>> Regards,
>>>
>>>      Sven
>>>
>>>> -----Ursprüngliche Nachricht-----
>>>> Von: Sven Schwermer <sven@svenschwermer.de>
>>>> Gesendet: Dienstag, 3. Mai 2022 13:27
>>>> An: linux-leds@vger.kernel.org; linux-kernel@vger.kernel.org; pavel@ucw.cz;
>>>> robh+dt@kernel.org; krzysztof.kozlowski+dt@linaro.org; dmurphy@ti.com;
>>>> devicetree@vger.kernel.org
>>>> Cc: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
>>>> Betreff: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property
>>>>
>>>> From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
>>>>
>>>> This allows to assign intensity values to the indivisual sub LEDs
>>>> (colors) at driver probe time, i.e. most commonly at kernel boot time.
>>>> This is crucial for setting a specific color early in the boot process.
>>>>
>>>> Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
>>>> ---
>>>>
>>>> Notes:
>>>>       V1->V2: no changes
>>>>
>>>>    .../devicetree/bindings/leds/leds-class-multicolor.yaml    | 7 +++++++
>>>>    1 file changed, 7 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
>>>> b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
>>>> index 37445c68cdef..c483967a847c 100644
>>>> --- a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
>>>> +++ b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
>>>> @@ -31,6 +31,13 @@ patternProperties:
>>>>              include/linux/leds/common.h.
>>>>            enum: [ 8, 9 ]
>>>>
>>>> +      default-intensities:
>>>> +        description: |
>>>> +          This parameter, if present, sets the initial intensities of the
>>>> +          individual colors. This array must have the same length as the
>>>> +          multi-color LED has sub LEDs (colors).
>>>> +        $ref: /schemas/types.yaml#/definitions/uint32-array
>>>> +
>>>>        $ref: "common.yaml#"
>>>>
>>>>        required:
>>>> --
>>>> 2.36.0
>>>

Re: AW: AW: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Jacek Anaszewski]

Hi Sven and Sven,

On 5/4/22 11:24, Sven Schwermer wrote:
> Hi Sven,
> 
> I did consider placing the property into the multicolor's sub nodes. 
> However, multicolor LEDs are not required to have firmware sub nodes. At 
> least the multicolor class API does not make any assumptions about this.

So this is something to be clarified. The whole idea relies on having
sub-nodes in the multi-led node.

> One possible solution that I came up with is to do something like this:
> 
> multi-led {
>      color = <LED_COLOR_ID_RGB>;
>      default-intensities = <
>          LED_COLOR_ID_RED 100
>          LED_COLOR_ID_GREEN 0
>          LED_COLOR_ID_BLUE 0
>      >;
>      led-0 {
>          color = <LED_COLOR_ID_RED>;
>      };
>      led-1 {
>          color = <LED_COLOR_ID_GREEN>;
>      };
>      led-2 {
>          color = <LED_COLOR_ID_BLUE>;
>      };
> };
> 
[...]
>>
>>
>> Maybe it is better to define per Color like this:
>>
>> multi-led@0 {
>>     #address-cells = <1>;
>>     #size-cells = <0>;
>>     reg = <0x0>;
>>     color = <LED_COLOR_ID_RGB>;
>>     function = "eee-led-status";
>>     led-0 {
>>         color = <LED_COLOR_ID_RED>;
>>         default-intensity = 100
>>     };
>>     led-1 {
>>         color = <LED_COLOR_ID_GREEN>;
>>         default-intensity = 0
>>     };
>>     led-2 {
>>         color = <LED_COLOR_ID_BLUE>;
>>         default-intensity = 0
>>     };
>> };

I would go for this. Seems to be the most straightforward solution.

-- 
Best regards,
Jacek Anaszewski

Re: AW: AW: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Sven Schwermer]

Hi Jacek,

On 5/8/22 21:55, Jacek Anaszewski wrote:
> Hi Sven and Sven,
> 
> On 5/4/22 11:24, Sven Schwermer wrote:
>> Hi Sven,
>>
>> I did consider placing the property into the multicolor's sub nodes. 
>> However, multicolor LEDs are not required to have firmware sub nodes. 
>> At least the multicolor class API does not make any assumptions about 
>> this.
> 
> So this is something to be clarified. The whole idea relies on having
> sub-nodes in the multi-led node.

As far as I understand, multi-color LEDs don't require actual OF 
sub-nodes. The Turris Omnia LED driver doesn't have sub-nodes, see 
Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml

>>> Maybe it is better to define per Color like this:
>>>
>>> multi-led@0 {
>>>     #address-cells = <1>;
>>>     #size-cells = <0>;
>>>     reg = <0x0>;
>>>     color = <LED_COLOR_ID_RGB>;
>>>     function = "eee-led-status";
>>>     led-0 {
>>>         color = <LED_COLOR_ID_RED>;
>>>         default-intensity = 100
>>>     };
>>>     led-1 {
>>>         color = <LED_COLOR_ID_GREEN>;
>>>         default-intensity = 0
>>>     };
>>>     led-2 {
>>>         color = <LED_COLOR_ID_BLUE>;
>>>         default-intensity = 0
>>>     };
>>> };
> 
> I would go for this. Seems to be the most straightforward solution.

I agree, that this would be the best option. However, as noted above, 
this wouldn't be compatible with all existing multi-color drivers.

Best regards,
Sven

Re: AW: AW: [PATCH v2 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Jacek Anaszewski]

On 5/10/22 20:31, Sven Schwermer wrote:
> Hi Jacek,
> 
> On 5/8/22 21:55, Jacek Anaszewski wrote:
>> Hi Sven and Sven,
>>
>> On 5/4/22 11:24, Sven Schwermer wrote:
>>> Hi Sven,
>>>
>>> I did consider placing the property into the multicolor's sub nodes. 
>>> However, multicolor LEDs are not required to have firmware sub nodes. 
>>> At least the multicolor class API does not make any assumptions about 
>>> this.
>>
>> So this is something to be clarified. The whole idea relies on having
>> sub-nodes in the multi-led node.
> 
> As far as I understand, multi-color LEDs don't require actual OF 
> sub-nodes. The Turris Omnia LED driver doesn't have sub-nodes, see 
> Documentation/devicetree/bindings/leds/cznic,turris-omnia-leds.yaml

Ah, I forgot about that one and the related discussion.
In this case, yes, global array will do.

-- 
Best regards,
Jacek Anaszewski

[PATCH v3 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Sven Schwermer]

From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>

This allows to assign intensity values to the individual sub LEDs
(colors) at driver probe time, i.e. most commonly at kernel boot time.
This is crucial for setting a specific color early in the boot process.

Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
---

Notes:
    V1->V2: no changes
    V2->V3:
    - Use color-intensity mapping instead of simple intensity array
    - Add example DTS snippet

 .../bindings/leds/leds-class-multicolor.yaml  | 37 +++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
index f41d021ed677..41050de496f6 100644
--- a/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
+++ b/Documentation/devicetree/bindings/leds/leds-class-multicolor.yaml
@@ -31,6 +31,19 @@ patternProperties:
           include/linux/leds/common.h.
         enum: [ 8, 9 ]
 
+      default-intensities:
+        description: |
+          This parameter, if present, sets the initial intensities of the
+          individual colors. The format is a list of pairs, mapping an intensity
+          value to a sub LED identified by its color.
+        $ref: /schemas/types.yaml#/definitions/uint32-matrix
+        items:
+          minItems: 2
+          maxItems: 2
+          items:
+            - description: color identifier (LED_COLOR_ID_*)
+            - description: intensity value
+
     $ref: "common.yaml#"
 
     required:
@@ -38,4 +51,28 @@ patternProperties:
 
 additionalProperties: true
 
+examples:
+  - |
+    #include <dt-bindings/leds/common.h>
+
+    multi-led {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      color = <LED_COLOR_ID_RGB>;
+      default-intensities = <LED_COLOR_ID_RED 64>,
+                            <LED_COLOR_ID_BLUE 0>;
+      led@0 {
+        reg = <0>;
+        color = <LED_COLOR_ID_RED>;
+      };
+      led@1 {
+        reg = <1>;
+        color = <LED_COLOR_ID_GREEN>;
+      };
+      led@2 {
+        reg = <2>;
+        color = <LED_COLOR_ID_BLUE>;
+      };
+    };
 ...
-- 
2.36.0

[PATCH v3 2/2] leds: multicolor: Read default-intensities property

[Sven Schwermer]

From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>

This allows to assign intensity values taken from the firmware interface
(if available) to the indivisual sub LEDs (colors) at driver probe time,
i.e. most commonly at kernel boot time. This is crucial for setting a
specific color and early in the boot process. While it would be possible
to set a static color in the bootloader, this mechanism allows setting a
pattern (e.g. blinking) at a specific color.

Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
---

Notes:
    V1->V2: Fix mixup
    V2->V3: Use color-intensity mapping instead of simple intensity array

 drivers/leds/led-class-multicolor.c | 48 +++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/drivers/leds/led-class-multicolor.c b/drivers/leds/led-class-multicolor.c
index e317408583df..2900dd02fe41 100644
--- a/drivers/leds/led-class-multicolor.c
+++ b/drivers/leds/led-class-multicolor.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
+#include <linux/property.h>
 
 #include "leds.h"
 
@@ -116,6 +117,50 @@ static struct attribute *led_multicolor_attrs[] = {
 };
 ATTRIBUTE_GROUPS(led_multicolor);
 
+static void multi_load_default_intensities(struct device *parent,
+					   struct led_classdev_mc *mcled_cdev,
+					   struct fwnode_handle *fwnode)
+{
+	u32 intensities[2 * LED_COLOR_ID_MAX];
+	unsigned int j;
+	int len;
+	int ret;
+	int i;
+
+	len = fwnode_property_read_u32_array(fwnode, "default-intensities",
+					     NULL, 0);
+	if (len < 0) {
+		if (len != -ENODATA)
+			dev_warn(parent,
+				 "failed to read default-intensities property length: %d", ret);
+		return;
+	}
+	if (len % 2 != 0) {
+		dev_warn(parent, "default-intensities property has uneven number of values");
+		return;
+	}
+	if (len > ARRAY_SIZE(intensities)) {
+		dev_warn(parent, "default-intensities property has too many values");
+		return;
+	}
+
+	ret = fwnode_property_read_u32_array(fwnode, "default-intensities",
+					     intensities, len);
+	if (ret < 0) {
+		dev_warn(parent, "failed to read default-intensities property values: %d", ret);
+		return;
+	}
+
+	for (i = 0; i < len; i += 2) {
+		for (j = 0; j < mcled_cdev->num_colors; j++) {
+			if (intensities[i] == mcled_cdev->subled_info[j].color_index) {
+				mcled_cdev->subled_info[j].intensity = intensities[i + 1];
+				break;
+			}
+		}
+	}
+}
+
 int led_classdev_multicolor_register_ext(struct device *parent,
 				     struct led_classdev_mc *mcled_cdev,
 				     struct led_init_data *init_data)
@@ -134,6 +179,9 @@ int led_classdev_multicolor_register_ext(struct device *parent,
 	led_cdev = &mcled_cdev->led_cdev;
 	mcled_cdev->led_cdev.groups = led_multicolor_groups;
 
+	if (init_data && init_data->fwnode)
+		multi_load_default_intensities(parent, mcled_cdev, init_data->fwnode);
+
 	return led_classdev_register_ext(parent, led_cdev, init_data);
 }
 EXPORT_SYMBOL_GPL(led_classdev_multicolor_register_ext);
-- 
2.36.0

Re: [PATCH v3 1/2] dt-bindings: leds: Add multi-color default-intensities property

[Rob Herring]

On Thu, 05 May 2022 11:50:08 +0200, Sven Schwermer wrote:
> From: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
> 
> This allows to assign intensity values to the individual sub LEDs
> (colors) at driver probe time, i.e. most commonly at kernel boot time.
> This is crucial for setting a specific color early in the boot process.
> 
> Signed-off-by: Sven Schwermer <sven.schwermer@disruptive-technologies.com>
> ---
> 
> Notes:
>     V1->V2: no changes
>     V2->V3:
>     - Use color-intensity mapping instead of simple intensity array
>     - Add example DTS snippet
> 
>  .../bindings/leds/leds-class-multicolor.yaml  | 37 +++++++++++++++++++
>  1 file changed, 37 insertions(+)
> 

Acked-by: Rob Herring <robh@kernel.org>