> + /* > + * Check if the LED driver supports the requested mode provided by the > + * defined supported trigger to setup the LED to hw control mode. > + */ > + int (*hw_control_is_supported)(struct led_classdev *led_cdev, > + unsigned long flags); Hi Christian This needs better documentation. What is the expected return value? My initial implementation for the Marvell driver did not work. I returned -EINVAL if it was not supported and some value >= 0 if it was supported. And most times, it was > 0, not 0. However, when i look at the trigger code: /* Check if the requested mode is supported */ ret = led_cdev->hw_control_is_supported(led_cdev, hw_mode); if (ret) return ret; *can_use_hw_control = true; Anything other than 0 means it is not supported. Andrew