This is a Linux driver for a family of similar LED display controllers which are used in some boards to drive 7-segment LED displays and, optionally, provide input support for up to a few tens of buttons.

The bus between the CPU and the display driver IC is accessed purely by bit-banging three GPIO pins (which are defined in the DTS file, example included).

Driver supports arbitrary character output (limited by 7 segment geometry), an additional bitmap overlay (which can be used to light additional icons on the display), variable brightness, on/off, Linux input device support for button input.

Additionaly, a highly configurable daemon program is provided that will fill the LED display with various useful information.

What was tested and WILL work:

• The LED display on a X92 AMLogic S912-based Android TV box. This box uses an FD628 display controller and a common-anode LED display. This board has no input buttons connected to FD628.

What was not tested but SHOULD work:

• Display controllers based on the following chips should be 100% compatible: PT6964, SM1628, TM1623, FD268.
• Display controllers compatible with FD620 also seems to work.

What was not tested but COULD work:

• The Linux input event code has not been tested yet due to missing hardware. However, I believe it should work, because I have tested it by modifying the code so that it thinks some hardware buttons are pressed.

To use this driver, copy the subdirectory vfd into AMLogic kernel tree, into the directory drivers/amlogic/input/.