Re: Clarification regarding multicolor leds

[Luca Weiss <luca@z3ntu.xyz>]

Hi Jacek

On Samstag, 24. Oktober 2020 21:34:38 CET Jacek Anaszewski wrote:
> Hi Luca,
> 
> On 10/24/20 12:48 AM, Luca Weiss wrote:
> > Hi,
> > I'm currently experimenting with the qcom lpg[0] which is a driver for the
> > rgb notification led found on e.g. Snapdragon 801 devices (and many
> > more), specifically my example is about the Fairphone 2
> > (msm8974-fairphone-fp2).
> > 
> > [0]
> > https://lore.kernel.org/lkml/20201021201224.3430546-1-bjorn.andersson@lin
> > aro.org/> 
> > My dts is looking like the following (abbreviated):
> >      [in lpg node]
> >      multi-led {
> >      
> >          color = <LED_COLOR_ID_MULTI>;
> >          function = LED_FUNCTION_STATUS;
> >          ....
> >      
> >      };
> > 
> > I'm comparing this to the PinePhone where the leds are defined as follows:
> >      [in gpio-leds node]
> >      blue {
> >      
> >          function = LED_FUNCTION_INDICATOR;
> >          color = <LED_COLOR_ID_BLUE>;
> >      
> >      };
> >      
> >      green {
> >      
> >          function = LED_FUNCTION_INDICATOR;
> >          color = <LED_COLOR_ID_GREEN>;
> >      
> >      };
> >      
> >      red {
> >      
> >          function = LED_FUNCTION_INDICATOR;
> >          color = <LED_COLOR_ID_RED>;
> >      
> >      };
> > 
> > (sidenote: the LED_FUNCTION_INDICATOR should probably also be
> > LED_FUNCTION_STATUS there; the dts was made before the better descriptions
> > for the defines have been added)
> > 
> > This gets the following directories created in /sys/class/leds/:
> >      blue:indicator
> >      green:indicator
> >      red:indicator
> > 
> > But with the multicolor led on the Fairphone 2 only a directory with the
> > name of "multi-led" gets created which I would have expected to be
> > "multicolor:status" instead.
> 
> This is because the driver from patch set [0] does not use *ext()
> multicolor registration API, but follows old-fashion LED name
> initialization via 'name' property of struct led_classdev, which is
> initialized to DT 'label' value or DT node name if the former is absent.

Right, I remember now having done something similar with my sgm3140 flash led 
driver half a year ago, thanks for the reminder!
With the qcom-lpg driver using the _ext function it works as expected.

@Bjorn I've prepared a diff for your patches at
https://public.z3ntu.xyz/tmp/lpg.diff where 
1. LED_COLOR_ID_MULTI is replaced with LED_COLOR_ID_RGB based on these emails
2. The example in the documentation uses LED_FUNCTION_STATUS (see description 
for the constant in include/dt-bindings/leds/common.h)
3. The _ext registration api now gets used, see e.g. commit 5b4b723c483f

Thanks for your help, really appreciate it!
Regards
Luca