Re: [PATCH/RFC v9 06/19] DT: Add documentation for the mfd Maxim max77693

From: Sylwester Nawrocki
Date: Wed Dec 10 2014 - 07:20:28 EST


Hi,

On 04/12/14 17:12, Pavel Machek wrote:
>>>> +- maxim,boost-mode :
>>>> > >>+ In boost mode the device can produce up to 1.2A of total current
>>>> > >>+ on both outputs. The maximum current on each output is reduced
>>>> > >>+ to 625mA then. If there are two child led nodes defined then boost
>>>> > >>+ is enabled by default.
>>>> > >>+ Possible values:
>>>> > >>+ MAX77693_LED_BOOST_OFF - no boost,
>>>> > >>+ MAX77693_LED_BOOST_ADAPTIVE - adaptive mode,
>>>> > >>+ MAX77693_LED_BOOST_FIXED - fixed mode.
>>>> > >>+- maxim,boost-vout : Output voltage of the boost module in millivolts.
>>>> > >>+- maxim,vsys-min : Low input voltage level in millivolts. Flash is not fired
>>>> > >>+ if chip estimates that system voltage could drop below this level due
>>>> > >>+ to flash power consumption.
>>>> > >>+
>>>> > >>+Required properties of the LED child node:
>>>> > >>+- label : see Documentation/devicetree/bindings/leds/common.txt
>>>> > >>+- maxim,fled_id : Identifier of the fled output the led is connected to;
>>> > >
>>> > >I'm pretty sure this will be needed for about every chip that can drive
>>> > >multiple LEDs. Shouldn't it be documented in the generic documentation?
>> >
>> > OK.
>
> Well... "fled_id" is not exactly suitable name. On other busses, it
> would be "reg = <1>"?

I think we need to clarify what the LED device node subnodes really mean.
I thought initially they describe a physical current output of the LED
controller, but it turns out the subnode corresponds to a LED attached
to the LED controller. Since a LED can be connected to multiple outputs
of the LED controller I think 'reg' property doesn't make sense here.

Then presumably we should use a property in each subnode, telling which
LED controller outputs a LED is connected to?

For instance, if we assign numbers 0, 1 to FLED1, FLED2 outputs of
MAX77693 and there is just one LED connected to those outputs we would
have something like:

max77693: led {
compatible = "maxim,max77693-led";
...
led1 {
maxim,fled-sources = <0 1>;
...
};
};

Feel free to propose better name for the property, I guess we need to
avoid "maxim,current-sources" due to ambiguity of the word "current".

--
Regards,
Sylwester
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