Documentation/leds/leds-lp5562.rst

   1 ========================
   2 Kernel driver for lp5562
   3 ========================
   4
   5 * TI LP5562 LED Driver
   6
   7 Author: Milo(Woogyom) Kim <milo.kim@ti.com>
   8
   9 Description
  10 ===========
  11
  12   LP5562 can drive up to 4 channels. R/G/B and White.
  13   LEDs can be controlled directly via the led class control interface.
  14
  15   All four channels can be also controlled using the engine micro programs.
  16   LP5562 has the internal program memory for running various LED patterns.
  17   For the details, please refer to 'firmware' section in leds-lp55xx.txt
  18
  19 Device attribute
  20 ================
  21
  22 engine_mux
  23   3 Engines are allocated in LP5562, but the number of channel is 4.
  24   Therefore each channel should be mapped to the engine number.
  25
  26   Value: RGB or W
  27
  28   This attribute is used for programming LED data with the firmware interface.
  29   Unlike the LP5521/LP5523/55231, LP5562 has unique feature for the engine mux,
  30   so additional sysfs is required
  31
  32   LED Map
  33
  34   ===== === ===============================
  35   Red   ... Engine 1 (fixed)
  36   Green ... Engine 2 (fixed)
  37   Blue  ... Engine 3 (fixed)
  38   White ... Engine 1 or 2 or 3 (selective)
  39   ===== === ===============================
  40
  41 How to load the program data using engine_mux
  42 =============================================
  43
  44   Before loading the LP5562 program data, engine_mux should be written between
  45   the engine selection and loading the firmware.
  46   Engine mux has two different mode, RGB and W.
  47   RGB is used for loading RGB program data, W is used for W program data.
  48
  49   For example, run blinking green channel pattern::
  50
  51     echo 2 > /sys/bus/i2c/devices/xxxx/select_engine     # 2 is for green channel
  52     echo "RGB" > /sys/bus/i2c/devices/xxxx/engine_mux    # engine mux for RGB
  53     echo 1 > /sys/class/firmware/lp5562/loading
  54     echo "4000600040FF6000" > /sys/class/firmware/lp5562/data
  55     echo 0 > /sys/class/firmware/lp5562/loading
  56     echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
  57
  58   To run a blinking white pattern::
  59
  60     echo 1 or 2 or 3 > /sys/bus/i2c/devices/xxxx/select_engine
  61     echo "W" > /sys/bus/i2c/devices/xxxx/engine_mux
  62     echo 1 > /sys/class/firmware/lp5562/loading
  63     echo "4000600040FF6000" > /sys/class/firmware/lp5562/data
  64     echo 0 > /sys/class/firmware/lp5562/loading
  65     echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
  66
  67 How to load the predefined patterns
  68 ===================================
  69
  70   Please refer to 'leds-lp55xx.txt"
  71
  72 Setting Current of Each Channel
  73 ===============================
  74
  75   Like LP5521 and LP5523/55231, LP5562 provides LED current settings.
  76   The 'led_current' and 'max_current' are used.
  77
  78 Example of Platform data
  79 ========================
  80
  81 ::
  82
  83         static struct lp55xx_led_config lp5562_led_config[] = {
  84                 {
  85                         .name           = "R",
  86                         .chan_nr        = 0,
  87                         .led_current    = 20,
  88                         .max_current    = 40,
  89                 },
  90                 {
  91                         .name           = "G",
  92                         .chan_nr        = 1,
  93                         .led_current    = 20,
  94                         .max_current    = 40,
  95                 },
  96                 {
  97                         .name           = "B",
  98                         .chan_nr        = 2,
  99                         .led_current    = 20,
 100                         .max_current    = 40,
 101                 },
 102                 {
 103                         .name           = "W",
 104                         .chan_nr        = 3,
 105                         .led_current    = 20,
 106                         .max_current    = 40,
 107                 },
 108         };
 109
 110         static int lp5562_setup(void)
 111         {
 112                 /* setup HW resources */
 113         }
 114
 115         static void lp5562_release(void)
 116         {
 117                 /* Release HW resources */
 118         }
 119
 120         static void lp5562_enable(bool state)
 121         {
 122                 /* Control of chip enable signal */
 123         }
 124
 125         static struct lp55xx_platform_data lp5562_platform_data = {
 126                 .led_config     = lp5562_led_config,
 127                 .num_channels   = ARRAY_SIZE(lp5562_led_config),
 128                 .setup_resources   = lp5562_setup,
 129                 .release_resources = lp5562_release,
 130                 .enable            = lp5562_enable,
 131         };
 132
 133 To configure the platform specific data, lp55xx_platform_data structure is used
 134
 135
 136 If the current is set to 0 in the platform data, that channel is
 137 disabled and it is not visible in the sysfs.