Adds OneXPlayer HID configuration driver. In this initial driver patch, add the RGB interface for the first generation of HID based RGB control. This interface provides the following attributes: - brightness: provided by the LED core, this works in a fairly unique way on this device. The hardware accepts 5 brightness values (0-4), which affects the brightness of the multicolor and animated effects built into the MCU firmware. For monocolor settings, the device expects the hardware brightness value to be pushed to maximum, then we apply brightness adjustments mathematically based on % (0-100). This leads to some odd conversion as we need the brightness slider to reach the full range, but it has no affect when incrementing between the division points for other effects. - multi-intensity: provided by the LED core for red, green, and blue. - effect: Allows the MCU to set 19 individual effects. - effect_index: Lists the 19 valid effect names for the interface. - enabled: Allows the MCU to toggle the RGB interface on/off. - enabled_index: Lists the valid states for enabled. - speed: Allows the MCU to set the animation rate for the various effects. - speed_range: Lists the valid range of speed (0-9). The MCU also has a few odd quirks that make sending multiple synchronous events challenging. It will essentially freeze if it receives another message before it has finished processing the last command. It also will not reply if you wait on it using a completion. To get around this, we do a 200ms sleep inside a work queue thread and debounce all but the most recent message using a 50ms mod_delayed_work. This will cache the last write, queue the work, then return so userspace can release its write thread. The work queue is only used for brightness/multi-intensity as that is the path likely to receive rapid successive writes. Reviewed-by: Zhouwang Huang <honjow311@gmail.com> Tested-by: Zhouwang Huang <honjow311@gmail.com> Signed-off-by: Derek J. Clark <derekjohn.clark@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.com>