Kernel driver for lp5521 ======================== * National Semiconductor LP5521 led driver chip * Datasheet: http://www.national.com/pf/LP/LP5521.html Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com) Description ----------- LP5521 can drive up to 3 channels. Leds can be controlled directly via the led class control interface. Channels have generic names: lp5521:channelx, where x is 0 .. 2 All three channels can be also controlled using the engine micro programs. More details of the instructions can be found from the public data sheet. Control interface for the engines: x is 1 .. 3 enginex_mode : disabled, load, run enginex_load : store program (visible only in engine load mode) Example (start to blink the channel 2 led): cd /sys/class/leds/lp5521:channel2/device echo "load" > engine3_mode echo "037f4d0003ff6000" > engine3_load echo "run" > engine3_mode stop the engine: echo "disabled" > engine3_mode sysfs contains a selftest entry. The test communicates with the chip and checks that the clock mode is automatically set to the requested one. Each channel has its own led current settings. /sys/class/leds/lp5521:channel0/led_current - RW /sys/class/leds/lp5521:channel0/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 2. static struct lp5521_led_config lp5521_led_config[] = { { .chan_nr = 0, .led_current = 50, .max_current = 130, }, { .chan_nr = 1, .led_current = 0, .max_current = 130, }, { .chan_nr = 2, .led_current = 0, .max_current = 130, } }; static int lp5521_setup(void) { /* setup HW resources */ } static void lp5521_release(void) { /* Release HW resources */ } static void lp5521_enable(bool state) { /* Control of chip enable signal */ } static struct lp5521_platform_data lp5521_platform_data = { .led_config = lp5521_led_config, .num_channels = ARRAY_SIZE(lp5521_led_config), .clock_mode = LP5521_CLOCK_EXT, .setup_resources = lp5521_setup, .release_resources = lp5521_release, .enable = lp5521_enable, }; If the current is set to 0 in the platform data, that channel is disabled and it is not visible in the sysfs.