Re: [PATCH 1/2] backlight: led_bl: Add devm_led_backlight_register() helper

[Daniel Thompson <daniel@riscstar.com>]

On Mon, Aug 17, 2026 at 07:08:14PM +0200, A. Sverdlin wrote:
> From: Alexander Sverdlin <alexander.sverdlin@siemens.com>
>
> The led-backlight driver could so far only be instantiated from a
> device-tree node with the "led-backlight" compatible. This makes it
> impossible for a self-contained LED provider (e.g. a hot-pluggable I2C
> LED controller) to expose a backlight interface tied to its own
> lifetime.
>
> Factor the actual backlight registration out of the probe path into a
> shared led_bl_register() helper and export devm_led_backlight_register(),
> which registers a backlight class device driven by a single LED, without
> device tree and bound to the caller's device lifetime. The backlight
> device and the LED sysfs handover are now devres-managed, so the probe
> path shrinks and the explicit .remove callback is no longer needed.

Please can you split this patch into two pieces to make review easier.
One to introduce make the backlight device and LED sysfs handover devre
-managed and the other to introduce devm_led_backlight_register().


> diff --git a/include/linux/led_bl.h b/include/linux/led_bl.h
> new file mode 100644
> index 0000000000000..e38e4d62bf653
> --- /dev/null
> +++ b/include/linux/led_bl.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_LED_BL_H
> +#define _LINUX_LED_BL_H
> +
> +#include <linux/kconfig.h>
> +
> +struct device;
> +struct led_classdev;
> +
> +#if IS_REACHABLE(CONFIG_BACKLIGHT_LED)
> +int devm_led_backlight_register(struct device *dev, struct led_classdev *led);
> +#else
> +static inline int devm_led_backlight_register(struct device *dev,
> +					      struct led_classdev *led)
> +{
> +	return 0;

This should not return success; it has not succeeded in registering a
backlight.
> +}
> +#endif


Daniel.