[PATCH v3 1/2] dt-bindings: leds: Read max-brightness from devicetree

[PATCH v3 1/2] dt-bindings: leds: Read max-brightness from devicetree

[Astrid Rost]

Normally, the maximum brightness is determined by the hardware, and this
property is not required. This property is used to set a software limit.
It could happen that an LED is made so bright that it gets damaged or
causes damage due to restrictions in a specific system, such as mounting
conditions.
Note that this flag is mainly used for PWM-LEDs, where it is not possible
to map brightness to current. Drivers for other controllers should use
led-max-microamp.

Signed-off-by: Astrid Rost <astrid.rost@axis.com>
---
 Documentation/devicetree/bindings/leds/common.yaml | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/common.yaml b/Documentation/devicetree/bindings/leds/common.yaml
index 11aedf1650a1..16f08d0939ce 100644
--- a/Documentation/devicetree/bindings/leds/common.yaml
+++ b/Documentation/devicetree/bindings/leds/common.yaml
@@ -160,6 +160,18 @@ properties:
       For flash LED controllers with configurable current this property is
       mandatory for the LEDs in the non-flash modes (e.g. torch or indicator).
 
+  max-brightness:
+    description:
+      Normally, the maximum brightness is determined by the hardware, and this
+      property is not required. This property is used to set a software limit.
+      It could happen that an LED is made so bright that it gets damaged or
+      causes damage due to restrictions in a specific system, such as mounting
+      conditions.
+      Note that this flag is mainly used for PWM-LEDs, where it is not possible
+      to map brightness to current. Drivers for other controllers should use
+      led-max-microamp.
+    $ref: /schemas/types.yaml#definitions/uint32
+
   panic-indicator:
     description:
       This property specifies that the LED should be used, if at all possible,
-- 
2.30.2

[PATCH v3 2/2] led: led-class: Read max-brightness from devicetree

[Astrid Rost]

Normally, the maximum brightness is determined by the hardware, and this
property is not required. This property is used to set a software limit.
It could happen that an LED is made so bright that it gets damaged or
causes damage due to restrictions in a specific system, such as mounting
conditions.
Note that this flag is mainly used for PWM-LEDs, where it is not possible
to map brightness to current. Drivers for other controllers should use
led-max-microamp.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Astrid Rost <astrid.rost@axis.com>
---
 drivers/leds/led-class.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 9255bc11f99d..ce652abf9336 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -457,6 +457,10 @@ int led_classdev_register_ext(struct device *parent,
 			if (fwnode_property_present(init_data->fwnode,
 						    "retain-state-shutdown"))
 				led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;
+
+			fwnode_property_read_u32(init_data->fwnode,
+				"max-brightness",
+				&led_cdev->max_brightness);
 		}
 	} else {
 		proposed_name = led_cdev->name;
-- 
2.30.2

Re: [PATCH v3 2/2] led: led-class: Read max-brightness from devicetree

[Jacek Anaszewski]

Hi Astrid,

Thanks for the update.

On 7/3/23 15:03, Astrid Rost wrote:
> Normally, the maximum brightness is determined by the hardware, and this
> property is not required. This property is used to set a software limit.
> It could happen that an LED is made so bright that it gets damaged or
> causes damage due to restrictions in a specific system, such as mounting
> conditions.
> Note that this flag is mainly used for PWM-LEDs, where it is not possible
> to map brightness to current. Drivers for other controllers should use
> led-max-microamp.
> 
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Astrid Rost <astrid.rost@axis.com>
> ---
>   drivers/leds/led-class.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index 9255bc11f99d..ce652abf9336 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -457,6 +457,10 @@ int led_classdev_register_ext(struct device *parent,
>   			if (fwnode_property_present(init_data->fwnode,
>   						    "retain-state-shutdown"))
>   				led_cdev->flags |= LED_RETAIN_AT_SHUTDOWN;
> +
> +			fwnode_property_read_u32(init_data->fwnode,
> +				"max-brightness",
> +				&led_cdev->max_brightness);
>   		}
>   	} else {
>   		proposed_name = led_cdev->name;

For the whole set:

Acked-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

-- 
Best regards,
Jacek Anaszewski

Re: [PATCH v3 1/2] dt-bindings: leds: Read max-brightness from devicetree

[Krzysztof Kozlowski]

On 03/07/2023 15:03, Astrid Rost wrote:
> Normally, the maximum brightness is determined by the hardware, and this
> property is not required. This property is used to set a software limit.
> It could happen that an LED is made so bright that it gets damaged or
> causes damage due to restrictions in a specific system, such as mounting
> conditions.
> Note that this flag is mainly used for PWM-LEDs, where it is not possible
> to map brightness to current. Drivers for other controllers should use
> led-max-microamp.
> 
> Signed-off-by: Astrid Rost <astrid.rost@axis.com>

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Best regards,
Krzysztof

Re: [PATCH v3 1/2] dt-bindings: leds: Read max-brightness from devicetree

[Rob Herring]

On Mon, 03 Jul 2023 15:03:12 +0200, Astrid Rost wrote:
> Normally, the maximum brightness is determined by the hardware, and this
> property is not required. This property is used to set a software limit.
> It could happen that an LED is made so bright that it gets damaged or
> causes damage due to restrictions in a specific system, such as mounting
> conditions.
> Note that this flag is mainly used for PWM-LEDs, where it is not possible
> to map brightness to current. Drivers for other controllers should use
> led-max-microamp.
> 
> Signed-off-by: Astrid Rost <astrid.rost@axis.com>
> ---
>  Documentation/devicetree/bindings/leds/common.yaml | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 

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

Re: [PATCH v3 1/2] dt-bindings: leds: Read max-brightness from devicetree

[Lee Jones]

On Mon, 03 Jul 2023, Astrid Rost wrote:

> Normally, the maximum brightness is determined by the hardware, and this
> property is not required. This property is used to set a software limit.
> It could happen that an LED is made so bright that it gets damaged or
> causes damage due to restrictions in a specific system, such as mounting
> conditions.
> Note that this flag is mainly used for PWM-LEDs, where it is not possible
> to map brightness to current. Drivers for other controllers should use
> led-max-microamp.
> 
> Signed-off-by: Astrid Rost <astrid.rost@axis.com>
> ---
>  Documentation/devicetree/bindings/leds/common.yaml | 12 ++++++++++++
>  1 file changed, 12 insertions(+)

Applied, thanks

-- 
Lee Jones [李琼斯]

Re: [PATCH v3 2/2] led: led-class: Read max-brightness from devicetree

[Lee Jones]

On Mon, 03 Jul 2023, Astrid Rost wrote:

> Normally, the maximum brightness is determined by the hardware, and this
> property is not required. This property is used to set a software limit.
> It could happen that an LED is made so bright that it gets damaged or
> causes damage due to restrictions in a specific system, such as mounting
> conditions.
> Note that this flag is mainly used for PWM-LEDs, where it is not possible
> to map brightness to current. Drivers for other controllers should use
> led-max-microamp.
> 
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Astrid Rost <astrid.rost@axis.com>
> ---
>  drivers/leds/led-class.c | 4 ++++
>  1 file changed, 4 insertions(+)

Applied, thanks

-- 
Lee Jones [李琼斯]