Re: [PATCH/RFC v10 03/19] DT: leds: Add led-sources property

From: Rob Herring
Date: Mon Jan 12 2015 - 08:52:51 EST


On Mon, Jan 12, 2015 at 2:32 AM, Jacek Anaszewski
<j.anaszewski@xxxxxxxxxxx> wrote:
> On 01/09/2015 07:33 PM, Rob Herring wrote:
>>
>> On Fri, Jan 9, 2015 at 9:22 AM, Jacek Anaszewski
>> <j.anaszewski@xxxxxxxxxxx> wrote:
>>>
>>> Add a property for defining the device outputs the LED
>>> represented by the DT child node is connected to.
>>>
>>> Signed-off-by: Jacek Anaszewski <j.anaszewski@xxxxxxxxxxx>
>>> Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
>>> Cc: Bryan Wu <cooloney@xxxxxxxxx>
>>> Cc: Richard Purdie <rpurdie@xxxxxxxxx>
>>> Cc: Rob Herring <robh+dt@xxxxxxxxxx>
>>> Cc: Pawel Moll <pawel.moll@xxxxxxx>
>>> Cc: Mark Rutland <mark.rutland@xxxxxxx>
>>> Cc: Ian Campbell <ijc+devicetree@xxxxxxxxxxxxxx>
>>> Cc: Kumar Gala <galak@xxxxxxxxxxxxxx>
>>> ---
>>> Documentation/devicetree/bindings/leds/common.txt | 5 +++++
>>> 1 file changed, 5 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/leds/common.txt
>>> b/Documentation/devicetree/bindings/leds/common.txt
>>> index a2c3f7a..29295bf 100644
>>> --- a/Documentation/devicetree/bindings/leds/common.txt
>>> +++ b/Documentation/devicetree/bindings/leds/common.txt
>>> @@ -1,6 +1,10 @@
>>> Common leds properties.
>>>
>>> Optional properties for child nodes:
>>> +- led-sources : Array of bits signifying the LED current regulator
>>> outputs the
>>> + LED represented by the child node is connected to (1 -
>>> the LED
>>> + is connected to the output, 0 - the LED isn't connected
>>> to the
>>> + output).
>>
>>
>> Sorry, I just don't understand this.
>
>
> In some Flash LED devices one LED can be connected to one or more
> electric current outputs, which allows for multiplying the maximum
> current allowed for the LED. Each sub-LED is represented by a child
> node in the DT binding of the Flash LED device and it needs to declare
> which outputs it is connected to. In the example below the led-sources
> property is a two element array, which means that the flash LED device
> has two current outputs, and the bits signify if the LED is connected
> to the output.

Sounds like a regulator for which we already have bindings for and we
have a driver for regulator based LEDs (but no binding for it). Please
use the regulator binding.

> Do your doubts stem from the ambiguity of the word "current" or the
> form of the description itself is unclear? Probably there should be
> explicit explanation added that the size of the array depends on the
> number of current outputs of the flash LED device.

The size of the array and meaning of array indexes was not clear.

Rob

>
>
>>> - label : The label for this LED. If omitted, the label is
>>> taken from the node name (excluding the unit address).
>>>
>>> @@ -33,6 +37,7 @@ system-status {
>>>
>>> camera-flash {
>>> label = "Flash";
>>> + led-sources = <1 0>;
>>> max-microamp = <50000>;
>>> flash-max-microamp = <320000>;
>>> flash-timeout-us = <500000>;
>>> --
>>> 1.7.9.5
>>>
>>
>
> --
> Best Regards,
> Jacek Anaszewski
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