[PATCH] leds: lp50xx: Read default intensity from devicetree

[PATCH] leds: lp50xx: Read default intensity from devicetree

[Tobias Johansson]

Read the default-intensity property for each LP50xx multicolor
component so that the configured color intensities are available
when brightness is applied. This allows LEDs to use the intended
RGB values without first writing multi_intensity from userspace.

Leave the intensity at zero when the property is absent.

Signed-off-by: Tobias Johansson <tobias.johansson@axis.com>
---
 drivers/leds/leds-lp50xx.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/leds/leds-lp50xx.c b/drivers/leds/leds-lp50xx.c
index 20bfb315bda1..019a3e3cad05 100644
--- a/drivers/leds/leds-lp50xx.c
+++ b/drivers/leds/leds-lp50xx.c
@@ -522,6 +522,8 @@ static int lp50xx_probe_dt(struct lp50xx *priv)
 				dev_err(priv->dev, "reg %i out of range\n", multi_index);
 				return -EINVAL;
 			}
+			fwnode_property_read_u32(led_node, "default-intensity",
+						 &mc_led_info[multi_index].intensity);
 
 			mc_led_info[multi_index].color_index = color_id;
 			mc_led_info[multi_index].max_intensity = 255;

---
base-commit: 05b4738b0078f7d6f154f68068a11c8a0635e9df
change-id: 20260914-b4-leds-lp50xx-default-intensity-345d4cc702b4

Best regards,
-- 
Tobias Johansson <tobias.johansson@axis.com>

Re: [PATCH] leds: lp50xx: Read default intensity from devicetree

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found no new issues
in this patch, but noticed 1 related pre-existing issue it does not
introduce:
- [Critical] leds: lp50xx: heap out-of-bounds access in
  lp50xx_brightness_set() [1]
--

commit 79b801d6a9355ec03170294fd226b03df2a33733
Author: Tobias Johansson <tobias.johansson@axis.com>

leds: lp50xx: Read default intensity from devicetree

This commit reads the default-intensity property from device tree for each
LP50xx multicolor sub-LED component during probe.

> diff --git a/drivers/leds/leds-lp50xx.c b/drivers/leds/leds-lp50xx.c
> index 20bfb315bda1d..019a3e3cad057 100644
> --- a/drivers/leds/leds-lp50xx.c
> +++ b/drivers/leds/leds-lp50xx.c
> @@ -522,6 +522,8 @@ static int lp50xx_probe_dt(struct lp50xx *priv)
>  				dev_err(priv->dev, "reg %i out of range\n", multi_index);
>  				return -EINVAL;
>  			}
> +			fwnode_property_read_u32(led_node, "default-intensity",
> +						 &mc_led_info[multi_index].intensity);
>  
>  			mc_led_info[multi_index].color_index = color_id;
>  			mc_led_info[multi_index].max_intensity = 255;

[Severity: Critical]
This problem wasn't introduced by this patch, but can num_colors exceed
LP50XX_LEDS_PER_MODULE and cause an out-of-bounds access on mc_led_info[]
[1]?

mc_led_info is allocated with LP50XX_LEDS_PER_MODULE (3) elements, and
lp50xx_probe_dt() checks that multi_index < LP50XX_LEDS_PER_MODULE, but
num_colors is incremented unconditionally for every child node. If a
device tree defines more than three sub-LED nodes that reuse valid reg
indices, led->mc_cdev.num_colors will exceed 3, causing
multi_intensity_store() and lp50xx_brightness_set() to read and write past
the end of subled_info[].

[1] https://sashiko.dev/#/bug/linux-a0c116ab-2f34-4f53-a007-d7a42f28677b

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261109-b4-leds-lp50xx-default-intensity-v1-1-0a04a3533df6@axis.com?part=1