| 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 define CONFIG_STATUS_LED in the board config file. | |
| If the LED support is only for a single board, define CONFIG_BOARD_SPECIFIC_LED | |
| in the board config file. | |
| At a minimum, these macros must be defined at | |
| STATUS_LED_BIT | |
| STATUS_LED_STATE | |
| STATUS_LED_PERIOD | |
| If there are multiple status LED's define | |
| STATUS_LED_BIT<n> | |
| STATUS_LED_STATE<n> | |
| STATUS_LED_PERIOD<n> | |
| Where <n> can a integer 1 through 3. | |
| 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 STATUS_LED_BIT's. Mapping the value to a physical LED is the | |
| reponsiblity of the __led_* function. | |
| STATUS_LED_STATE is the initial state of the LED. It should be set to one of | |
| these values: STATUS_LED_OFF or STATUS_LED_ON. | |
| STATUS_LED_PERIOD is how long is the LED blink period. This usually set to | |
| (CONFIG_SYS_HZ / <N>) where <N> is the frequency of the blink. Typical values | |
| range from 2 to 10. | |
| Some other LED macros | |
| STATUS_LED_BOOT is the LED to light when the board is booting. This must be a | |
| valid STATUS_LED_BIT value. | |
| STATUS_LED_RED is the red LED. It is used signal errors. This must be a valid | |
| STATUS_LED_BIT value. Other similar color LED's are STATUS_LED_YELLOW and | |
| STATUS_LED_BLUE. | |
| These board must define these functions | |
| __led_init is called once to initialize the LED to 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 | |
| CONFIG_TQM8xxL. | |
| TBD : Describe general support via asm/status_led.h |