Re: [PATCH v7 1/1] leds: LED driver for TI LP3952 6-Channel Color LED

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

On 07/05/2016 02:12 PM, Rafael J. Wysocki wrote:
> On Tue, Jul 5, 2016 at 12:47 PM, Jacek Anaszewski
> <j.anaszewski@samsung.com> wrote:
>> PING
>>
>>
>> On 06/29/2016 12:54 PM, Jacek Anaszewski wrote:
>>>
>>> On 06/29/2016 12:07 PM, Tony wrote:
>>>>
>>>>
>>>> On 29/06/16 07:52, Jacek Anaszewski wrote:
>>>>>
>>>>> Hi Rafael,
>>>>
>>>>
>>>>>>> +#ifdef CONFIG_ACPI
>>>>>>> +static const struct acpi_device_id lp3952_acpi_match[] = {
>>>>>>> +    {LP3952_ACPI_NAME, 0},
>>>>>>
>>>>>>
>>>>>> No, you can't use "PRP0001" in this list.
>>>>>>
>>>>>>> +    {}
>>>>>>> +};
>>>>>>> +
>>>>>>> +MODULE_DEVICE_TABLE(acpi, lp3952_acpi_match);
>>>>>>
>>>>>>
>>>>>> And you don't need this for the "PRP0001" thing to work.  The core will
>>>>>> take care of it for you then.
>>>>>>
>>>>>>> +#endif
>>>>>>
>>>>>>
>>>>>> So the entire ACPI block can be dropped for now.
>>>>>>
>>>>>> And the driver doesn't have to depend on CONFIG_ACPI any more, does it?
>>>>>
>>>>>
>>>>> The driver currently supports probing only with ACPI.
>>>>> I have one question BTW: isn't there anything similar to the device tree
>>>>> bindings documentation required for ACPI overlays?
>>>>> Pointer to the discussion which led us to this solution:
>>>>>
>>>>> http://www.spinics.net/lists/linux-leds/msg06230.html
>>>>>
>>>> _DSD is working now. I managed to get "PRP0001" working as suggested by
>>>> Rafael in
>>>> http://marc.info/?l=linux-acpi&m=146711623115228&w=2
>>>> with _DSD
>>>
>>>
>>> Thanks for the link.
>>>
>>> Rafael, "Package" entries seem to mimic Device Tree properties defined
>>> in the common leds bindings. Would it be possible to make it even
>>> more compatible and define every LED connected to the LED controller
>>> in the form of a child node, similarly as in case of LED DT bindings?
>>>
>>> See Documentation/devicetree/bindings/leds/common.txt and other
>>> bindings in Documentation/devicetree/bindings/leds.
>
> I'm not sure what you mean.
>
> If somebody decides to arrange the data in their ACPI tables to follow
> that scheme, it will just work IMO.
>
> Is there anything more that needs to be done in the kernel here?

In case of Device Tree based platforms it is customary to define each
LED as a child node of the LED controller node. LED names can then
be obtained from the 'label' property or DT node name.
Tony has encountered some issues [1] while trying to follow this
pattern. Tony, could you please double check that?

[1] http://www.spinics.net/lists/linux-leds/msg06230.html

-- 
Best regards,
Jacek Anaszewski