Re: [PATCH v4 05/11] [RFC] leds: led-class: Add devicetree support to led_get()

[Andy Shevchenko <andy.shevchenko@xxxxxxxxx>]

On Thu, Jan 19, 2023 at 3:01 PM Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
>
> Turn of_led_get() into a more generic __of_led_get() helper function,
> which can lookup LEDs in devicetree by either name or index.
>
> And use this new helper to add devicetree support to the generic
> (non devicetree specific) [devm_]led_get() function.
>
> This uses the standard devicetree pattern of adding a -names string array
> to map names to the indexes for an array of resources.
>
> Note the new led-names property for LED consumers is not added
> to the devicetree documentation because there seems to be no
> documentation for the leds property itself to extend it with this.
> It seems that how LED consumers should be described is not documented
> at all ATM.
>
> This patch is marked as RFC because of both the missing devicetree
> documentation and because there are no devicetree users of
> the generic [devm_]led_get() function for now.

FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>

Yeah, it's a pity we have no documentation for the LED properties...

> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
>  drivers/leds/led-class.c | 37 ++++++++++++++++++++++++++++---------
>  1 file changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
> index 6dff57c41e96..22f658c750d1 100644
> --- a/drivers/leds/led-class.c
> +++ b/drivers/leds/led-class.c
> @@ -234,19 +234,18 @@ static struct led_classdev *led_module_get(struct device *led_dev)
>         return led_cdev;
>  }
>
> -/**
> - * of_led_get() - request a LED device via the LED framework
> - * @np: device node to get the LED device from
> - * @index: the index of the LED
> - *
> - * Returns the LED device parsed from the phandle specified in the "leds"
> - * property of a device tree node or a negative error-code on failure.
> - */
> -struct led_classdev *of_led_get(struct device_node *np, int index)
> +static struct led_classdev *__of_led_get(struct device_node *np, int index,
> +                                        const char *name)
>  {
>         struct device *led_dev;
>         struct device_node *led_node;
>
> +       /*
> +        * For named LEDs, first look up the name in the "led-names" property.
> +        * If it cannot be found, then of_parse_phandle() will propagate the error.
> +        */
> +       if (name)
> +               index = of_property_match_string(np, "led-names", name);
>         led_node = of_parse_phandle(np, "leds", index);
>         if (!led_node)
>                 return ERR_PTR(-ENOENT);
> @@ -256,6 +255,19 @@ struct led_classdev *of_led_get(struct device_node *np, int index)
>
>         return led_module_get(led_dev);
>  }
> +
> +/**
> + * of_led_get() - request a LED device via the LED framework
> + * @np: device node to get the LED device from
> + * @index: the index of the LED
> + *
> + * Returns the LED device parsed from the phandle specified in the "leds"
> + * property of a device tree node or a negative error-code on failure.
> + */
> +struct led_classdev *of_led_get(struct device_node *np, int index)
> +{
> +       return __of_led_get(np, index, NULL);
> +}
>  EXPORT_SYMBOL_GPL(of_led_get);
>
>  /**
> @@ -329,9 +341,16 @@ EXPORT_SYMBOL_GPL(devm_of_led_get);
>  struct led_classdev *led_get(struct device *dev, char *function)
>  {
>         struct led_lookup_data *lookup;
> +       struct led_classdev *led_cdev;
>         const char *led_name = NULL;
>         struct device *led_dev;
>
> +       if (dev->of_node) {
> +               led_cdev = __of_led_get(dev->of_node, -1, function);
> +               if (!IS_ERR(led_cdev) || PTR_ERR(led_cdev) != -ENOENT)
> +                       return led_cdev;
> +       }
> +
>         mutex_lock(&leds_lookup_lock);
>         list_for_each_entry(lookup, &leds_lookup_list, list) {
>                 if (!strcmp(lookup->consumer_dev_name, dev_name(dev)) &&
> --
> 2.39.0
>


-- 
With Best Regards,
Andy Shevchenko