xref: /openbmc/u-boot/doc/README.LED_display (revision 2d2811c2)
1LED display internal API
2=======================================
3
4This README describes the LED display API.
5
6The API is defined by the include file include/led-display.h
7
8The first step in to define CONFIG_CMD_DISPLAY in the board config file.
9Then you need to provide the following functions to access LED display:
10
11void display_set(int cmd);
12
13This function should control the state of the LED display. Argument is
14an ORed combination of the following values:
15 DISPLAY_CLEAR	-- clear the display
16 DISPLAY_HOME	-- set the position to the beginning of display
17
18int display_putc(char c);
19
20This function should display it's parameter on the LED display in the
21current position. Returns the displayed character on success or -1 in
22case of failure.
23
24With this functions defined 'display' command will display it's
25arguments on the LED display (or clear the display if called without
26arguments).
27