Kernel driver for lp5523 ======================== * National Semiconductor LP5523 led driver chip * Datasheet: http://www.national.com/pf/LP/LP5523.html Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com) Description ----------- LP5523 can drive up to 9 channels. Leds can be controlled directly via the led class control interface. Channels have generic names: lp5523:channelx where x is 0...8 The chip provides 3 engines. Each engine can control channels without interaction from the main CPU. Details of the micro engine code can be found from the public data sheet. Leds can be muxed to different channels. Control interface for the engines: x is 1 .. 3 enginex_mode : disabled, load, run enginex_load : microcode load (visible only in load mode) enginex_leds : led mux control (visible only in load mode) cd /sys/class/leds/lp5523:channel2/device echo "load" > engine3_mode echo "9d80400004ff05ff437f0000" > engine3_load echo "111111111" > engine3_leds echo "run" > engine3_mode sysfs contains a selftest entry. It measures each channel voltage level and checks if it looks reasonable. If the level is too high, the led is missing; if the level is too low, there is a short circuit. Selftest uses always the current from the platform data. Each channel contains led current settings. /sys/class/leds/lp5523:channel2/led_current - RW /sys/class/leds/lp5523:channel2/max_current - RO Format: 10x mA i.e 10 means 1.0 mA Example platform data: Note - chan_nr can have values between 0 and 8. static struct lp5523_led_config lp5523_led_config[] = { { .chan_nr = 0, .led_current = 50, .max_current = 130, }, ... }, { .chan_nr = 8, .led_current = 50, .max_current = 130, } }; static int lp5523_setup(void) { /* Setup HW resources */ } static void lp5523_release(void) { /* Release HW resources */ } static void lp5523_enable(bool state) { /* Control chip enable signal */ } static struct lp5523_platform_data lp5523_platform_data = { .led_config = lp5523_led_config, .num_channels = ARRAY_SIZE(lp5523_led_config), .clock_mode = LP5523_CLOCK_EXT, .setup_resources = lp5523_setup, .release_resources = lp5523_release, .enable = lp5523_enable, };