diff options
Diffstat (limited to 'drivers/leds/trigger/ledtrig-netdev.c')
| -rw-r--r-- | drivers/leds/trigger/ledtrig-netdev.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/leds/trigger/ledtrig-netdev.c b/drivers/leds/trigger/ledtrig-netdev.c index bd68da15c723..836610292b37 100644 --- a/drivers/leds/trigger/ledtrig-netdev.c +++ b/drivers/leds/trigger/ledtrig-netdev.c @@ -38,6 +38,16 @@ * tx - LED blinks on transmitted data * rx - LED blinks on receive data * + * Note: If the user selects a mode that is not supported by hw, default + * behavior is to fall back to software control of the LED. However not every + * hw supports software control. LED callbacks brightness_set() and + * brightness_set_blocking() are NULL in this case. hw_control_is_supported() + * should use available means supported by hw to inform the user that selected + * mode isn't supported by hw. This could be switching off the LED or any + * hw blink mode. If software control fallback isn't possible, we return + * -EOPNOTSUPP to the user, but still store the selected mode. This is needed + * in case an intermediate unsupported mode is necessary to switch from one + * supported mode to another. */ struct led_netdev_data { @@ -318,6 +328,7 @@ static ssize_t netdev_led_attr_store(struct device *dev, const char *buf, size_t size, enum led_trigger_netdev_modes attr) { struct led_netdev_data *trigger_data = led_trigger_get_drvdata(dev); + struct led_classdev *led_cdev = trigger_data->led_cdev; unsigned long state, mode = trigger_data->mode; int ret; int bit; @@ -363,6 +374,10 @@ static ssize_t netdev_led_attr_store(struct device *dev, const char *buf, trigger_data->mode = mode; trigger_data->hw_control = can_hw_control(trigger_data); + if (!led_cdev->brightness_set && !led_cdev->brightness_set_blocking && + !trigger_data->hw_control) + return -EOPNOTSUPP; + set_baseline_state(trigger_data); return size; |