====== LCD Backlight ======
Most drivers use the //fbtft// backlight support to control backlight.
This is enabled if there is a 'led' gpio present.

These drivers will have backlight power control exposed in the sysfs filesystem.
<code>
# Turn off backlight
echo 1 | sudo tee /sys/class/backlight/*/bl_power

# Turn on backlight
echo 0 | sudo tee /sys/class/backlight/*/bl_power
</code>

Brightness is currently not supported (need a kernel PWM driver).

====== Give all users backlight control permissions ======
/etc/udev/rules.d/backlight-permissions.rules
<code>
SUBSYSTEM=="backlight",RUN+="/bin/chmod 666 /sys/class/backlight/%k/brightness /sys/class/backlight/%k/bl_power"
</code>

====== Backlight control outside of FBTFT ======
Wiring Pi can be used to dim the backlight.
<code>
sudo gpio mode 7 write
# Turn Off LCD backlight
sudo gpio write 7 0
# Turn On LCD backlight
sudo gpio write 7 1
</code>

====== References ======
 * [[https://github.com/notro/fbtft/wiki/Backlight|Backlight]]