tree de53af30b71dbde0bb9b72cba4dc42c2842491b6
parent 2332e91ff6b0758026ce68f049a74cda6e13b702
author Andrew Jeffery <andrew@aj.id.au> 1552891837 +1030
committer Andrew Jeffery <andrew@aj.id.au> 1554697130 +0930

physical: Conform to LED class kernel ABI

The kernel says the following about the LED sysfs interface:

> LED handling under Linux
> ========================
>
> In its simplest form, the LED class just allows control of LEDs from
> userspace. LEDs appear in /sys/class/leds/. The maximum brightness of the
> LED is defined in max_brightness file. The brightness file will set the brightness
> of the LED (taking a value 0-max_brightness). Most LEDs don't have hardware
> brightness support so will just be turned on for non-zero brightness settings.

The existing code assumed that max_brightness always held a value of
255 and defined a constant for it. Instead, use a class variable to
cache the max brightness for the associated LED.

Change-Id: I2d8f46de0cddac5f9d8ff5444449518bb4056130
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>