diff mbox series

[v1,2/2] dt: bindings: lp50xx: Add max-brightness as in leds-pwm

Message ID 20230629134722.3908637-3-astrid.rost@axis.com
State New
Headers show
Series [v1,1/2] led: leds-lp50xx: Add max-brightness as in leds-pwm | expand

Commit Message

Astrid Rost June 29, 2023, 1:47 p.m. UTC
Add max-brightness in order to reduce the current on the connected LEDs.
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.

Signed-off-by: Astrid Rost <astrid.rost@axis.com>
---
 Documentation/devicetree/bindings/leds/leds-lp50xx.yaml | 9 +++++++++
 1 file changed, 9 insertions(+)

Comments

Astrid Rost June 30, 2023, 7:23 a.m. UTC | #1
On 6/29/23 19:59, Rob Herring wrote:
> On Thu, Jun 29, 2023 at 03:47:22PM +0200, Astrid Rost wrote:
>> Add max-brightness in order to reduce the current on the connected LEDs.
>> 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.
>>
>> Signed-off-by: Astrid Rost <astrid.rost@axis.com>
>> ---
>>   Documentation/devicetree/bindings/leds/leds-lp50xx.yaml | 9 +++++++++
>>   1 file changed, 9 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml b/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
>> index 402c25424525..6a1425969cb4 100644
>> --- a/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
>> +++ b/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
>> @@ -73,6 +73,15 @@ patternProperties:
>>         '#size-cells':
>>           const: 0
>>   
>> +      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.
>> +        $ref: /schemas/types.yaml#definitions/uint32
> 
> We already have led-max-microamp. If this h/w works by controlling the
> current, then that is what you should use. "max-brightness" makes more
> sense for PWM based control.

Yes, I looked into this. This LED controller TI-LP5024 has only one flag 
as max current option, which allows to set between 35 mA and the default 
value 25.5 mA. This is not enough for our application.

> 
> If you do end up keeping this, it belongs in the 'led' nodes not the
> controller as brightness is a property of the LED, not the LED
> driver(controller). And it should be in common schema rather than
> defining the type yet again.

I will look moving it into the the LED generic bindings as Andy 
suggested. max_brightness is already there and handled correctly. It is 
just a matter of reading it from the devicetree.

> 
> Rob
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml b/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
index 402c25424525..6a1425969cb4 100644
--- a/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
+++ b/Documentation/devicetree/bindings/leds/leds-lp50xx.yaml
@@ -73,6 +73,15 @@  patternProperties:
       '#size-cells':
         const: 0
 
+      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.
+        $ref: /schemas/types.yaml#definitions/uint32
+
     patternProperties:
       "^led@[0-9a-f]+$":
         type: object