Re: [PATCH v5 1/2] dt: add cap11xx LED documentation

[Jacek Anaszewski <j.anaszewski@samsung.com>]

On 06/24/2015 09:28 AM, Jacek Anaszewski wrote:
> On 06/23/2015 08:07 PM, Dmitry Torokhov wrote:
>> On Tue, Jun 23, 2015 at 10:23:57AM -0700, Matt Ranostay wrote:
>>> On Tue, Jun 23, 2015 at 1:36 AM, Jacek Anaszewski
>>> <j.anaszewski@samsung.com> wrote:
>>>> On 06/22/2015 07:59 PM, Dmitry Torokhov wrote:
>>>>>
>>>>> On Wed, Jun 17, 2015 at 08:58:16PM -0700, Matt Ranostay wrote:
>>>>>>
>>>>>> Signed-off-by: Matt Ranostay <mranostay@gmail.com>
>>>>>> ---
>>>>>>    .../devicetree/bindings/input/cap11xx.txt          | 25
>>>>>> ++++++++++++++++++++++
>>>>>>    1 file changed, 25 insertions(+)
>>>>>>
>>>>>> diff --git a/Documentation/devicetree/bindings/input/cap11xx.txt
>>>>>> b/Documentation/devicetree/bindings/input/cap11xx.txt
>>>>>> index 7d0a300..09cdc43 100644
>>>>>> --- a/Documentation/devicetree/bindings/input/cap11xx.txt
>>>>>> +++ b/Documentation/devicetree/bindings/input/cap11xx.txt
>>>>>> @@ -38,6 +38,11 @@ Optional properties:
>>>>>>                                  defaults. The array must have
>>>>>> exactly six
>>>>>>                                  entries.
>>>>>>
>>>>>> +       linux,led-brightness:   Defines the ON brightness when the
>>>>>> optional LED
>>>>>> +                               functionality is used. Valid
>>>>>> values are
>>>>>> 1-15.
>>>>>> +                               By default a value of 15 is set.
>>>>>
>>>>>
>>>>> Please mention the device does not allow controlling brightness of
>>>>> leds
>>>>> individually and that is why this property is at device level, not
>>>>> individual led level.
>>>>
>>>>
>>>> I've just noticed that we have drivers/leds/leds-netxbig.c driver,
>>>> which
>>>> also doesn't allow controlling the LEDs on extension board
>>>> individually,
>>>> but it still does allow changing their brightness. I am leaning towards
>>>> allowing this also for this driver and adding similar comment in the
>>>> source code like at the line 218 of the aforementioned driver.
>>>> As a result this property wouldn't be required.
>>>>
>>>
>>> Ok that should be pretty simple to do. But seems kind weird to have
>>> each led channel to be changing the brightness of all.  Wouldn't the
>>> brightness sysfs entries of the other led channels be showing
>>> incorrect values?
>
> If you implemented brightness_get op it would show proper value.
> Assuming that the device allows reading current brightness.

Of course brightness_get wouldn't have to read the brightness
from the device, but return the value cached on on each call to
brightness_set for any LED class device exposed by the driver.

-- 
Best Regards,
Jacek Anaszewski