linux/Documentation/leds/leds-lp5523.txt
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   1Kernel driver for lp5523
   2========================
   3
   4* National Semiconductor LP5523 led driver chip
   5* Datasheet: http://www.national.com/pf/LP/LP5523.html
   6
   7Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo
   8Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com)
   9
  10Description
  11-----------
  12LP5523 can drive up to 9 channels. Leds can be controlled directly via
  13the led class control interface. Channels have generic names:
  14lp5523:channelx where x is 0...8
  15
  16The chip provides 3 engines. Each engine can control channels without
  17interaction from the main CPU. Details of the micro engine code can be found
  18from the public data sheet. Leds can be muxed to different channels.
  19
  20Control interface for the engines:
  21x is 1 .. 3
  22enginex_mode : disabled, load, run
  23enginex_load : microcode load (visible only in load mode)
  24enginex_leds : led mux control (visible only in load mode)
  25
  26cd /sys/class/leds/lp5523:channel2/device
  27echo "load" > engine3_mode
  28echo "9d80400004ff05ff437f0000" > engine3_load
  29echo "111111111" > engine3_leds
  30echo "run" > engine3_mode
  31
  32sysfs contains a selftest entry. It measures each channel
  33voltage level and checks if it looks reasonable. If the level is too high,
  34the led is missing; if the level is too low, there is a short circuit.
  35
  36Selftest uses always the current from the platform data.
  37
  38Each channel contains led current settings.
  39/sys/class/leds/lp5523:channel2/led_current - RW
  40/sys/class/leds/lp5523:channel2/max_current - RO
  41Format: 10x mA i.e 10 means 1.0 mA
  42
  43Example platform data:
  44
  45Note - chan_nr can have values between 0 and 8.
  46
  47static struct lp5523_led_config lp5523_led_config[] = {
  48        {
  49                .chan_nr        = 0,
  50                .led_current    = 50,
  51                .max_current    = 130,
  52        },
  53...
  54        }, {
  55                .chan_nr        = 8,
  56                .led_current    = 50,
  57                .max_current    = 130,
  58        }
  59};
  60
  61static int lp5523_setup(void)
  62{
  63        /* Setup HW resources */
  64}
  65
  66static void lp5523_release(void)
  67{
  68        /* Release HW resources */
  69}
  70
  71static void lp5523_enable(bool state)
  72{
  73        /* Control chip enable signal */
  74}
  75
  76static struct lp5523_platform_data lp5523_platform_data = {
  77        .led_config     = lp5523_led_config,
  78        .num_channels   = ARRAY_SIZE(lp5523_led_config),
  79        .clock_mode     = LP5523_CLOCK_EXT,
  80        .setup_resources   = lp5523_setup,
  81        .release_resources = lp5523_release,
  82        .enable            = lp5523_enable,
  83};
  84
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