| Status LED | |
| ======================================== | |
| This README describes the status LED API. | |
| The API is defined by the include file include/status_led.h | |
| The first step is to enable CONFIG_LED_STATUS in menuconfig: | |
| > Device Drivers > LED Support. | |
| If the LED support is only for specific board, enable | |
| CONFIG_LED_STATUS_BOARD_SPECIFIC in the menuconfig. | |
| Status LEDS 0 to 5 are enabled by the following configurations at menuconfig: | |
| CONFIG_STATUS_LED0, CONFIG_STATUS_LED1, ... CONFIG_STATUS_LED5 | |
| The following should be configured for each of the enabled LEDs: | |
| CONFIG_STATUS_LED_BIT<n> | |
| CONFIG_STATUS_LED_STATE<n> | |
| CONFIG_STATUS_LED_FREQ<n> | |
| Where <n> is an integer 1 through 5 (empty for 0). | |
| CONFIG_STATUS_LED_BIT is passed into the __led_* functions to identify which LED | |
| is being acted on. As such, the value choose must be unique with with respect to | |
| the other CONFIG_STATUS_LED_BIT's. Mapping the value to a physical LED is the | |
| reponsiblity of the __led_* function. | |
| CONFIG_STATUS_LED_STATE is the initial state of the LED. It should be set to one | |
| of these values: CONFIG_LED_STATUS_OFF or CONFIG_LED_STATUS_ON. | |
| CONFIG_STATUS_LED_FREQ determines the LED blink frequency. | |
| Values range from 2 to 10. | |
| Some other LED macros | |
| --------------------- | |
| CONFIG_STATUS_LED_BOOT is the LED to light when the board is booting. | |
| This must be a valid LED number (0-5). | |
| CONFIG_STATUS_LED_RED is the red LED. It is used to signal errors. This must be | |
| a valid LED number (0-5). Other similar color LED's macros are | |
| CONFIG_STATUS_LED_GREEN, CONFIG_STATUS_LED_YELLOW and CONFIG_STATUS_LED_BLUE. | |
| General LED functions | |
| --------------------- | |
| The following functions should be defined: | |
| __led_init is called once to initialize the LED to CONFIG_STATUS_LED_STATE. | |
| One time start up code should be placed here. | |
| __led_set is called to change the state of the LED. | |
| __led_toggle is called to toggle the current state of the LED. | |
| Colour LED | |
| ======================================== | |
| Colour LED's are at present only used by ARM. | |
| The functions names explain their purpose. | |
| coloured_LED_init | |
| red_LED_on | |
| red_LED_off | |
| green_LED_on | |
| green_LED_off | |
| yellow_LED_on | |
| yellow_LED_off | |
| blue_LED_on | |
| blue_LED_off | |
| These are weakly defined in arch/arm/lib/board.c to noops. Where applicable, define | |
| these functions in the board specific source. | |
| TBD : Describe older board dependent macros similar to what is done for | |
| TBD : Describe general support via asm/status_led.h |