Documentation/leds/leds-lp5523.txt

   1 Kernel driver for lp5523
   2 ========================
   3
   4 * National Semiconductor LP5523 led driver chip
   5 * Datasheet: http://www.national.com/pf/LP/LP5523.html
   6
   7 Authors: Mathias Nyman, Yuri Zaporozhets, Samu Onkalo
   8 Contact: Samu Onkalo (samu.p.onkalo-at-nokia.com)
   9
  10 Description
  11 -----------
  12 LP5523 can drive up to 9 channels. Leds can be controlled directly via
  13 the led class control interface.
  14 The name of each channel is configurable in the platform data - name and label.
  15 There are three options to make the channel name.
  16
  17 a) Define the 'name' in the platform data
  18 To make specific channel name, then use 'name' platform data.
  19 /sys/class/leds/R1               (name: 'R1')
  20 /sys/class/leds/B1               (name: 'B1')
  21
  22 b) Use the 'label' with no 'name' field
  23 For one device name with channel number, then use 'label'.
  24 /sys/class/leds/RGB:channelN     (label: 'RGB', N: 0 ~ 8)
  25
  26 c) Default
  27 If both fields are NULL, 'lp5523' is used by default.
  28 /sys/class/leds/lp5523:channelN  (N: 0 ~ 8)
  29
  30 LP5523 has the internal program memory for running various LED patterns.
  31 There are two ways to run LED patterns.
  32
  33 1) Legacy interface - enginex_mode, enginex_load and enginex_leds
  34   Control interface for the engines:
  35   x is 1 .. 3
  36   enginex_mode : disabled, load, run
  37   enginex_load : microcode load
  38   enginex_leds : led mux control
  39
  40   cd /sys/class/leds/lp5523:channel2/device
  41   echo "load" > engine3_mode
  42   echo "9d80400004ff05ff437f0000" > engine3_load
  43   echo "111111111" > engine3_leds
  44   echo "run" > engine3_mode
  45
  46   To stop the engine:
  47   echo "disabled" > engine3_mode
  48
  49 2) Firmware interface - LP55xx common interface
  50   For the details, please refer to 'firmware' section in leds-lp55xx.txt
  51
  52 LP5523 has three master faders. If a channel is mapped to one of
  53 the master faders, its output is dimmed based on the value of the master
  54 fader.
  55
  56 For example,
  57
  58   echo "123000123" > master_fader_leds
  59
  60 creates the following channel-fader mappings:
  61
  62   channel 0,6 to master_fader1
  63   channel 1,7 to master_fader2
  64   channel 2,8 to master_fader3
  65
  66 Then, to have 25% of the original output on channel 0,6:
  67
  68   echo 64 > master_fader1
  69
  70 To have 0% of the original output (i.e. no output) channel 1,7:
  71
  72   echo 0 > master_fader2
  73
  74 To have 100% of the original output (i.e. no dimming) on channel 2,8:
  75
  76   echo 255 > master_fader3
  77
  78 To clear all master fader controls:
  79
  80   echo "000000000" > master_fader_leds
  81
  82 Selftest uses always the current from the platform data.
  83
  84 Each channel contains led current settings.
  85 /sys/class/leds/lp5523:channel2/led_current - RW
  86 /sys/class/leds/lp5523:channel2/max_current - RO
  87 Format: 10x mA i.e 10 means 1.0 mA
  88
  89 Example platform data:
  90
  91 Note - chan_nr can have values between 0 and 8.
  92
  93 static struct lp55xx_led_config lp5523_led_config[] = {
  94         {
  95                 .name           = "D1",
  96                 .chan_nr        = 0,
  97                 .led_current    = 50,
  98                 .max_current    = 130,
  99         },
 100 ...
 101         {
 102                 .chan_nr        = 8,
 103                 .led_current    = 50,
 104                 .max_current    = 130,
 105         }
 106 };
 107
 108 static int lp5523_setup(void)
 109 {
 110         /* Setup HW resources */
 111 }
 112
 113 static void lp5523_release(void)
 114 {
 115         /* Release HW resources */
 116 }
 117
 118 static void lp5523_enable(bool state)
 119 {
 120         /* Control chip enable signal */
 121 }
 122
 123 static struct lp55xx_platform_data lp5523_platform_data = {
 124         .led_config     = lp5523_led_config,
 125         .num_channels   = ARRAY_SIZE(lp5523_led_config),
 126         .clock_mode     = LP55XX_CLOCK_EXT,
 127         .setup_resources   = lp5523_setup,
 128         .release_resources = lp5523_release,
 129         .enable            = lp5523_enable,
 130 };