Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 LP5521/LP5523/LP55231/LP5562/LP8501 Common Driver 2 ================================================= 3 4 Authors: Milo(Woogyom) Kim <milo.kim@ti.com> 5 6 Description 7 ----------- 8 LP5521, LP5523/55231, LP5562 and LP8501 have common features as below. 9 10 Register access via the I2C 11 Device initialization/deinitialization 12 Create LED class devices for multiple output channels 13 Device attributes for user-space interface 14 Program memory for running LED patterns 15 16 The LP55xx common driver provides these features using exported functions. 17 lp55xx_init_device() / lp55xx_deinit_device() 18 lp55xx_register_leds() / lp55xx_unregister_leds() 19 lp55xx_regsister_sysfs() / lp55xx_unregister_sysfs() 20 21 ( Driver Structure Data ) 22 23 In lp55xx common driver, two different data structure is used. 24 25 o lp55xx_led 26 control multi output LED channels such as led current, channel index. 27 o lp55xx_chip 28 general chip control such like the I2C and platform data. 29 30 For example, LP5521 has maximum 3 LED channels. 31 LP5523/55231 has 9 output channels. 32 33 lp55xx_chip for LP5521 ... lp55xx_led #1 34 lp55xx_led #2 35 lp55xx_led #3 36 37 lp55xx_chip for LP5523 ... lp55xx_led #1 38 lp55xx_led #2 39 . 40 . 41 lp55xx_led #9 42 43 ( Chip Dependent Code ) 44 45 To support device specific configurations, special structure 46 'lpxx_device_config' is used. 47 48 Maximum number of channels 49 Reset command, chip enable command 50 Chip specific initialization 51 Brightness control register access 52 Setting LED output current 53 Program memory address access for running patterns 54 Additional device specific attributes 55 56 ( Firmware Interface ) 57 58 LP55xx family devices have the internal program memory for running 59 various LED patterns. 60 This pattern data is saved as a file in the user-land or 61 hex byte string is written into the memory through the I2C. 62 LP55xx common driver supports the firmware interface. 63 64 LP55xx chips have three program engines. 65 To load and run the pattern, the programming sequence is following. 66 (1) Select an engine number (1/2/3) 67 (2) Mode change to load 68 (3) Write pattern data into selected area 69 (4) Mode change to run 70 71 The LP55xx common driver provides simple interfaces as below. 72 select_engine : Select which engine is used for running program 73 run_engine : Start program which is loaded via the firmware interface 74 firmware : Load program data 75 76 In case of LP5523, one more command is required, 'enginex_leds'. 77 It is used for selecting LED output(s) at each engine number. 78 In more details, please refer to 'leds-lp5523.txt'. 79 80 For example, run blinking pattern in engine #1 of LP5521 81 echo 1 > /sys/bus/i2c/devices/xxxx/select_engine 82 echo 1 > /sys/class/firmware/lp5521/loading 83 echo "4000600040FF6000" > /sys/class/firmware/lp5521/data 84 echo 0 > /sys/class/firmware/lp5521/loading 85 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine 86 87 For example, run blinking pattern in engine #3 of LP55231 88 Two LEDs are configured as pattern output channels. 89 echo 3 > /sys/bus/i2c/devices/xxxx/select_engine 90 echo 1 > /sys/class/firmware/lp55231/loading 91 echo "9d0740ff7e0040007e00a0010000" > /sys/class/firmware/lp55231/data 92 echo 0 > /sys/class/firmware/lp55231/loading 93 echo "000001100" > /sys/bus/i2c/devices/xxxx/engine3_leds 94 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine 95 96 To start blinking patterns in engine #2 and #3 simultaneously, 97 for idx in 2 3 98 do 99 echo $idx > /sys/class/leds/red/device/select_engine 100 sleep 0.1 101 echo 1 > /sys/class/firmware/lp5521/loading 102 echo "4000600040FF6000" > /sys/class/firmware/lp5521/data 103 echo 0 > /sys/class/firmware/lp5521/loading 104 done 105 echo 1 > /sys/class/leds/red/device/run_engine 106 107 Here is another example for LP5523. 108 Full LED strings are selected by 'engine2_leds'. 109 echo 2 > /sys/bus/i2c/devices/xxxx/select_engine 110 echo 1 > /sys/class/firmware/lp5523/loading 111 echo "9d80400004ff05ff437f0000" > /sys/class/firmware/lp5523/data 112 echo 0 > /sys/class/firmware/lp5523/loading 113 echo "111111111" > /sys/bus/i2c/devices/xxxx/engine2_leds 114 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine 115 116 As soon as 'loading' is set to 0, registered callback is called. 117 Inside the callback, the selected engine is loaded and memory is updated. 118 To run programmed pattern, 'run_engine' attribute should be enabled. 119 120 The pattern sequence of LP8501 is similar to LP5523. 121 However pattern data is specific. 122 Ex 1) Engine 1 is used 123 echo 1 > /sys/bus/i2c/devices/xxxx/select_engine 124 echo 1 > /sys/class/firmware/lp8501/loading 125 echo "9d0140ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data 126 echo 0 > /sys/class/firmware/lp8501/loading 127 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine 128 129 Ex 2) Engine 2 and 3 are used at the same time 130 echo 2 > /sys/bus/i2c/devices/xxxx/select_engine 131 sleep 1 132 echo 1 > /sys/class/firmware/lp8501/loading 133 echo "9d0140ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data 134 echo 0 > /sys/class/firmware/lp8501/loading 135 sleep 1 136 echo 3 > /sys/bus/i2c/devices/xxxx/select_engine 137 sleep 1 138 echo 1 > /sys/class/firmware/lp8501/loading 139 echo "9d0340ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data 140 echo 0 > /sys/class/firmware/lp8501/loading 141 sleep 1 142 echo 1 > /sys/class/leds/d1/device/run_engine 143 144 ( 'run_engine' and 'firmware_cb' ) 145 The sequence of running the program data is common. 146 But each device has own specific register addresses for commands. 147 To support this, 'run_engine' and 'firmware_cb' are configurable in each driver. 148 run_engine : Control the selected engine 149 firmware_cb : The callback function after loading the firmware is done. 150 Chip specific commands for loading and updating program memory. 151 152 ( Predefined pattern data ) 153 154 Without the firmware interface, LP55xx driver provides another method for 155 loading a LED pattern. That is 'predefined' pattern. 156 A predefined pattern is defined in the platform data and load it(or them) 157 via the sysfs if needed. 158 To use the predefined pattern concept, 'patterns' and 'num_patterns' should be 159 configured. 160 161 Example of predefined pattern data: 162 163 /* mode_1: blinking data */ 164 static const u8 mode_1[] = { 165 0x40, 0x00, 0x60, 0x00, 0x40, 0xFF, 0x60, 0x00, 166 }; 167 168 /* mode_2: always on */ 169 static const u8 mode_2[] = { 0x40, 0xFF, }; 170 171 struct lp55xx_predef_pattern board_led_patterns[] = { 172 { 173 .r = mode_1, 174 .size_r = ARRAY_SIZE(mode_1), 175 }, 176 { 177 .b = mode_2, 178 .size_b = ARRAY_SIZE(mode_2), 179 }, 180 } 181 182 struct lp55xx_platform_data lp5562_pdata = { 183 ... 184 .patterns = board_led_patterns, 185 .num_patterns = ARRAY_SIZE(board_led_patterns), 186 }; 187 188 Then, mode_1 and mode_2 can be run via through the sysfs. 189 190 echo 1 > /sys/bus/i2c/devices/xxxx/led_pattern # red blinking LED pattern 191 echo 2 > /sys/bus/i2c/devices/xxxx/led_pattern # blue LED always on 192 193 To stop running pattern, 194 echo 0 > /sys/bus/i2c/devices/xxxx/led_pattern