| 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 |
