1Status LED 2======================================== 3 4This README describes the status LED API. 5 6The API is defined by the include file include/status_led.h 7 8The first step is to define CONFIG_STATUS_LED in the board config file. 9 10If the LED support is only for a single board, define CONFIG_BOARD_SPECIFIC_LED 11in the board config file. 12 13At a minimum, these macros must be defined at 14STATUS_LED_BIT 15STATUS_LED_STATE 16STATUS_LED_PERIOD 17 18If there are multiple status LED's define 19STATUS_LED_BIT<n> 20STATUS_LED_STATE<n> 21STATUS_LED_PERIOD<n> 22 23Where <n> can a integer 1 through 3. 24 25STATUS_LED_BIT is passed into the __led_* functions to identify which LED is 26being acted on. As such, the value choose must be unique with with respect to 27the other STATUS_LED_BIT's. Mapping the value to a physical LED is the 28reponsiblity of the __led_* function. 29 30STATUS_LED_STATE is the initial state of the LED. It should be set to one of 31these values: STATUS_LED_OFF or STATUS_LED_ON. 32 33STATUS_LED_PERIOD is how long is the LED blink period. This usually set to 34(CONFIG_SYS_HZ / <N>) where <N> is the frequency of the blink. Typical values 35range from 2 to 10. 36 37Some other LED macros 38 39STATUS_LED_BOOT is the LED to light when the board is booting. This must be a 40valid STATUS_LED_BIT value. 41 42STATUS_LED_RED is the red LED. It is used signal errors. This must be a valid 43STATUS_LED_BIT value. Other similar color LED's are STATUS_LED_YELLOW and 44STATUS_LED_BLUE. 45 46These board must define these functions 47 48__led_init is called once to initialize the LED to STATUS_LED_STATE. One time 49start up code should be placed here. 50 51__led_set is called to change the state of the LED. 52 53__led_toggle is called to toggle the current state of the LED. 54 55Colour LED 56======================================== 57 58Colour LED's are at present only used by ARM. 59 60The functions names explain their purpose. 61 62coloured_LED_init 63red_LED_on 64red_LED_off 65green_LED_on 66green_LED_off 67yellow_LED_on 68yellow_LED_off 69blue_LED_on 70blue_LED_off 71 72These are weakly defined in arch/arm/lib/board.c to noops. Where applicable, define 73these functions in the board specific source. 74 75TBD : Describe older board dependent macros similar to what is done for 76CONFIG_TQM8xxL. 77 78TBD : Describe general support via asm/status_led.h 79