backlight: use exponential backlight control instead of linear.

Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>
drivers: video: Add backlight dimmer option

This is based on n5dim by @mzhou  https://github.com/mzhou/n5dim

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
drivers: video: gradual transitions for backlight dimmer

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
video: backlight: enable backlight_dimmer by default. Auto-brightness looks great with this.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
backlight: fix a bug where the screen would be completely dark or near darkness with backlight_dimmer enabled when the display dimmed. The brightness level can't be any lower than dev->min_brightness and previous code allowed that to happen, so fix it.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
backlight: clean the code.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
backlight: add minimum backlight brightness module param.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
backlight: scale max current when the brightness level is below 15 instead of using always 0.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>