xref: /openbmc/u-boot/doc/README.LED_display (revision 1032d97496f6d534bf0030a5779ff1cb38cc9ebf)
1*7f0d241dSIlya YanokLED display internal API
2*7f0d241dSIlya Yanok=======================================
3*7f0d241dSIlya Yanok
4*7f0d241dSIlya YanokThis README describes the LED display API.
5*7f0d241dSIlya Yanok
6*7f0d241dSIlya YanokThe API is defined by the include file include/led-display.h
7*7f0d241dSIlya Yanok
8*7f0d241dSIlya YanokThe first step in to define CONFIG_CMD_DISPLAY in the board config file.
9*7f0d241dSIlya YanokThen you need to provide the following functions to access LED display:
10*7f0d241dSIlya Yanok
11*7f0d241dSIlya Yanokvoid display_set(int cmd);
12*7f0d241dSIlya Yanok
13*7f0d241dSIlya YanokThis function should control the state of the LED display. Argument is
14*7f0d241dSIlya Yanokan ORed combination of the following values:
15*7f0d241dSIlya Yanok DISPLAY_CLEAR	-- clear the display
16*7f0d241dSIlya Yanok DISPLAY_HOME	-- set the position to the beginning of display
17*7f0d241dSIlya Yanok
18*7f0d241dSIlya Yanokint display_putc(char c);
19*7f0d241dSIlya Yanok
20*7f0d241dSIlya YanokThis function should display it's parameter on the LED display in the
21*7f0d241dSIlya Yanokcurrent position. Returns the displayed character on success or -1 in
22*7f0d241dSIlya Yanokcase of failure.
23*7f0d241dSIlya Yanok
24*7f0d241dSIlya YanokWith this functions defined 'display' command will display it's
25*7f0d241dSIlya Yanokarguments on the LED display (or clear the display if called without
26*7f0d241dSIlya Yanokarguments).
27