Complex triggers whilst available to all LEDs have LED specific
parameters and work on a per LED basis. The timer trigger is an example.
+The timer trigger will periodically change the LED brightness between
+LED_OFF and the current brightness setting. The "on" and "off" time can
+be specified via /sys/class/leds/<device>/delay_{on,off} in milliseconds.
+You can change the brightness value of a LED independently of the timer
+trigger. However, if you set the brightness value to LED_OFF it will
+also disable the timer trigger.
You can change triggers in a similar manner to the way an IO scheduler
is chosen (via /sys/class/leds/<device>/trigger). Trigger specific
Some LEDs can be programmed to blink without any CPU interaction. To
support this feature, a LED driver can optionally implement the
-blink_set() function (see <linux/leds.h>). If implemeted, triggers can
+blink_set() function (see <linux/leds.h>). If implemented, triggers can
attempt to use it before falling back to software timers. The blink_set()
function should return 0 if the blink setting is supported, or -EINVAL
otherwise, which means that LED blinking will be handled by software.
this case the driver should give back the chosen value through delay_on
and delay_off parameters to the leds subsystem.
-Any call to the brightness_set() callback function should cancel the
-previously programmed hardware blinking function so setting the brightness
-to 0 can also cancel the blinking of the LED.
+Setting the brightness to zero with brightness_set() callback function
+should completely turn off the LED and cancel the previously programmed
+hardware blinking function, if any.
Known Issues