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

From: Sylwester Nawrocki
Date: Fri Jan 16 2015 - 05:17:37 EST


Hi,

On 15/01/15 22:03, Pavel Machek wrote:
>> Perhaps we could use the 'reg' property to describe actual connections,
>> > I'm not sure if it's better than a LED specific property, e.g.
>> >
>> > max77387@52 {
>> > compatible = "nxp,max77387";
>> > #address-cells = <2>;
>> > #size-cells = <0>;
>> > reg = <0x52>;
>> >
>> > flash_led {
>> > reg = <1 1>;
>> > ...
>> > };
>> > };
>
> Normally, reg property is <start length>, if I understand things
> correctly? Would that be enough here, or would we be doing list of
> outputs?

In general the exact meaning depends on value of the #address-cells and
#size-cells properties in the parent node. In case as above #size-cells
is 0. You can find exact explanation in [1], at page 25.

Anyway, the above example might an abuse of the simple bus. I thought more
about a list of outputs, but the indexes wouldn't be contiguous, e.g.

curr. reg. outputs | "addres" value
--------------------------------
FLED2 FLED1 | reg
--------------------+-----------
0 1 | 0x00000001
1 0 | 0x00010000
1 1 | 0x00010001

But it might be not a good idea as Rob pointed out.

OTOH we could simply assign indices 1,2,3 to the above FLED1/2 output
combinations.

[1] https://www.power.org/wp-content/uploads/2012/06/Power_ePAPR_APPROVED_v1.1.pdf

--
Regards,
Sylwester
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/