@@ -209,6 +209,19 @@ static int led_bl_probe(struct platform_device *pdev)
return PTR_ERR(priv->bl_dev);
}
+ for (i = 0; i < priv->nb_leds; i++) {
+ struct device_link *link;
+
+ link = device_link_add(&pdev->dev, priv->leds[0]->dev->parent,
+ DL_FLAG_AUTOREMOVE_CONSUMER);
+ if (!link) {
+ dev_err(&pdev->dev, "Failed to add devlink (consumer %s, supplier %s)\n",
+ dev_name(&pdev->dev), dev_name(priv->leds[0]->dev->parent));
+ backlight_device_unregister(priv->bl_dev);
+ return -EINVAL;
+ }
+ }
+
for (i = 0; i < priv->nb_leds; i++) {
mutex_lock(&priv->leds[i]->led_access);
led_sysfs_disable(priv->leds[i]);
led-backlight is a consumer of one or multiple LED class devices, but no devlink is created for such supplier-producer relationship. One consequence is that removal ordered is not correctly enforced. Issues happen for example with the following sections in a device tree overlay: // An LED driver chip pca9632@62 { compatible = "nxp,pca9632"; reg = <0x62>; // ... addon_led_pwm: led-pwm@3 { reg = <3>; label = "addon:led:pwm"; }; }; backlight-addon { compatible = "led-backlight"; leds = <&addon_led_pwm>; brightness-levels = <255>; default-brightness-level = <255>; }; On removal of the above overlay, the LED driver can be removed before the backlight device, resulting in: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010 ... Call trace: led_put+0xe0/0x140 devm_led_release+0x6c/0x98 Fix by adding a devlink between the consuming led-backlight device and the supplying LED device. Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com> --- This patch first appeared in v4. --- drivers/video/backlight/led_bl.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)