linux-kernel - Re: [PATCH v8 6/6] leds: Add a multicolor LED driver to group monochromatic LEDs

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Message-ID: <CAHp75Vca0SKPkyPM_14Zny+Vn0a=hKWRfYW9qzTpN8AVZ_R_YQ@mail.gmail.com>
Date:   Tue, 28 Mar 2023 20:20:27 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Jean-Jacques Hiblot <jjhiblot@...phandler.com>
Cc:     lee.jones@...aro.org, pavel@....cz, robh+dt@...nel.org,
        sven.schwermer@...ruptive-technologies.com,
        krzysztof.kozlowski+dt@...aro.org, johan+linaro@...nel.org,
        marijn.suijten@...ainline.org, jacek.anaszewski@...il.com,
        linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8 6/6] leds: Add a multicolor LED driver to group
 monochromatic LEDs

On Tue, Mar 28, 2023 at 7:15 PM Jean-Jacques Hiblot
<jjhiblot@...phandler.com> wrote:
>
> Grouping multiple monochrome LEDs into a multicolor LED device has a few
> benefits over handling the group in user-space:
> - The state of the LEDs relative to each other is consistent. In other
>   words, if 2 threads competes to set the LED to green and red, the
>   end-result cannot be black or yellow.
> - The multicolor LED as a whole can be driven through the sysfs LED
>   interface.

...

> +config LEDS_GROUP_MULTICOLOR
> +       tristate "LEDs group multi-color support"
> +       depends on OF || COMPILE_TEST

Why is OF a dependency?
Can't we make it a firmware provider agnostic solution from day 1?

> +       help
> +         This option enables support for monochrome LEDs that are
> +         grouped into multicolor LEDs.
> +         This useful in the case where LEDs of different colors are

This is

> +         physically grouped in a single multi-color LED and driven
> +         by a controller that doesn't have multi-color support.
> +
> +         To compile this driver as a module, choose M here: the module
> +         will be called leds-group-multicolor.

...

> +               led_cdev = devm_of_led_get_optional(dev, count);

I don't see how this is OF specific to this driver. Maybe it needs to
be patched first, so we will have something non-OF specific?

> +               if (IS_ERR(led_cdev))
> +                       return dev_err_probe(dev, PTR_ERR(led_cdev), "Unable to get LED #%d",
> +                                            count);

At least we need to have a FIXME or so here.

-- 
With Best Regards,
Andy Shevchenko