Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) ====================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) One-shot LED Trigger
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) ====================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) This is a LED trigger useful for signaling the user of an event where there are
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) no clear trap points to put standard led-on and led-off settings.  Using this
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) trigger, the application needs only to signal the trigger when an event has
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) happened, than the trigger turns the LED on and than keeps it off for a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) specified amount of time.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) This trigger is meant to be usable both for sporadic and dense events.  In the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) first case, the trigger produces a clear single controlled blink for each
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) event, while in the latter it keeps blinking at constant rate, as to signal
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) that the events are arriving continuously.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) A one-shot LED only stays in a constant state when there are no events.  An
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) additional "invert" property specifies if the LED has to stay off (normal) or
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) on (inverted) when not rearmed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) The trigger can be activated from user space on led class devices as shown
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) below::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)   echo oneshot > trigger
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) This adds sysfs attributes to the LED that are documented in:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) Documentation/ABI/testing/sysfs-class-led-trigger-oneshot
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) Example use-case: network devices, initialization::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30)   echo oneshot > trigger # set trigger for this led
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31)   echo 33 > delay_on     # blink at 1 / (33 + 33) Hz on continuous traffic
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)   echo 33 > delay_off
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) interface goes up::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36)   echo 1 > invert # set led as normally-on, turn the led on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) packet received/transmitted::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)   echo 1 > shot # led starts blinking, ignored if already blinking
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) interface goes down::
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44)   echo 0 > invert # set led as normally-off, turn the led off