1 Status LED 2 ======================================== 3 4 This README describes the status LED API. 5 6 The API is defined by the include file include/status_led.h 7 8 The first step is to enable CONFIG_LED_STATUS in menuconfig: 9 > Device Drivers > LED Support. 10 11 If the LED support is only for specific board, enable 12 CONFIG_LED_STATUS_BOARD_SPECIFIC in the menuconfig. 13 14 Status LEDS 0 to 5 are enabled by the following configurations at menuconfig: 15 CONFIG_STATUS_LED0, CONFIG_STATUS_LED1, ... CONFIG_STATUS_LED5 16 17 The following should be configured for each of the enabled LEDs: 18 CONFIG_STATUS_LED_BIT<n> 19 CONFIG_STATUS_LED_STATE<n> 20 CONFIG_STATUS_LED_FREQ<n> 21 Where <n> is an integer 1 through 5 (empty for 0). 22 23 CONFIG_STATUS_LED_BIT is passed into the __led_* functions to identify which LED 24 is being acted on. As such, the value choose must be unique with with respect to 25 the other CONFIG_STATUS_LED_BIT's. Mapping the value to a physical LED is the 26 reponsiblity of the __led_* function. 27 28 CONFIG_STATUS_LED_STATE is the initial state of the LED. It should be set to one 29 of these values: CONFIG_LED_STATUS_OFF or CONFIG_LED_STATUS_ON. 30 31 CONFIG_STATUS_LED_FREQ determines the LED blink frequency. 32 Values range from 2 to 10. 33 34 Some other LED macros 35 --------------------- 36 37 CONFIG_STATUS_LED_BOOT is the LED to light when the board is booting. 38 This must be a valid LED number (0-5). 39 40 CONFIG_STATUS_LED_RED is the red LED. It is used to signal errors. This must be 41 a valid LED number (0-5). Other similar color LED's macros are 42 CONFIG_STATUS_LED_GREEN, CONFIG_STATUS_LED_YELLOW and CONFIG_STATUS_LED_BLUE. 43 44 General LED functions 45 --------------------- 46 The following functions should be defined: 47 48 __led_init is called once to initialize the LED to CONFIG_STATUS_LED_STATE. 49 One time start 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 55 Colour LED 56 ======================================== 57 58 Colour LED's are at present only used by ARM. 59 60 The functions names explain their purpose. 61 62 coloured_LED_init 63 red_LED_on 64 red_LED_off 65 green_LED_on 66 green_LED_off 67 yellow_LED_on 68 yellow_LED_off 69 blue_LED_on 70 blue_LED_off 71 72 These are weakly defined in arch/arm/lib/board.c to noops. Where applicable, define 73 these functions in the board specific source. 74 75 TBD : Describe older board dependent macros similar to what is done for 76 77 TBD : Describe general support via asm/status_led.h 78
