Re: [PATCH] [v2] leds: gpio: make legacy gpiolib interface optional

["Arnd Bergmann" <arnd@arndb.de>]

On Tue, May 5, 2026, at 15:25, Andy Shevchenko wrote:
> On Tue, May 05, 2026 at 04:19:36PM +0300, Andy Shevchenko wrote:
>> On Tue, May 05, 2026 at 03:10:28PM +0200, Arnd Bergmann wrote:
>> > On Mon, May 4, 2026, at 09:31, Andy Shevchenko wrote:
>> >        struct gpio_desc *gpiod;
>> > 
>> >        gpiod = devm_gpiod_get_index_optional(dev, NULL, idx, GPIOD_OUT_LOW);
>> 
>> >        if (gpiod && !IS_ERR(gpiod));
>> 
>> And this is not needed. The below is NULL-aware.
>
> To be clear
>
>         struct gpio_desc *gpiod;
>
>         gpiod = devm_gpiod_get_index_optional(dev, NULL, idx, GPIOD_OUT_LOW);
>         if (!IS_ERR(gpiod))
>                 gpiod_set_consumer_name(gpiod, template->name);
>
>         return gpiod;
>
> But looking at the original code, I would leave another return, so

Right, I actually had this at first, but decided to keep the NULL
check because that was used in the driver already.

I've dropped it again now.

>> >   gpiod = devm_gpiod_get_index_optional(dev, template->name, i, GPIOD_OUT_LOW);
>> > 
>> > Did I get that right? If so, I'll fold that in as another
>
> Nope, the con_id != consumer name. Can't be done this way.

I see. I had tried to find an existing interface that sets
the consumer name and saw that gpiod_get_index() internally
uses con_id as the label if set, but I missed that this would
break the actual lookup in gpio_desc_table_match() because the
13 lookup tables are of course all defined by index rather than
by name.

      Arnd