0001 =================================================
0002 LP5521/LP5523/LP55231/LP5562/LP8501 Common Driver
0003 =================================================
0004
0005 Authors: Milo(Woogyom) Kim <milo.kim@ti.com>
0006
0007 Description
0008 -----------
0009 LP5521, LP5523/55231, LP5562 and LP8501 have common features as below.
0010
0011 Register access via the I2C
0012 Device initialization/deinitialization
0013 Create LED class devices for multiple output channels
0014 Device attributes for user-space interface
0015 Program memory for running LED patterns
0016
0017 The LP55xx common driver provides these features using exported functions.
0018
0019 lp55xx_init_device() / lp55xx_deinit_device()
0020 lp55xx_register_leds() / lp55xx_unregister_leds()
0021 lp55xx_regsister_sysfs() / lp55xx_unregister_sysfs()
0022
0023 ( Driver Structure Data )
0024
0025 In lp55xx common driver, two different data structure is used.
0026
0027 * lp55xx_led
0028 control multi output LED channels such as led current, channel index.
0029 * lp55xx_chip
0030 general chip control such like the I2C and platform data.
0031
0032 For example, LP5521 has maximum 3 LED channels.
0033 LP5523/55231 has 9 output channels::
0034
0035 lp55xx_chip for LP5521 ... lp55xx_led #1
0036 lp55xx_led #2
0037 lp55xx_led #3
0038
0039 lp55xx_chip for LP5523 ... lp55xx_led #1
0040 lp55xx_led #2
0041 .
0042 .
0043 lp55xx_led #9
0044
0045 ( Chip Dependent Code )
0046
0047 To support device specific configurations, special structure
0048 'lpxx_device_config' is used.
0049
0050 - Maximum number of channels
0051 - Reset command, chip enable command
0052 - Chip specific initialization
0053 - Brightness control register access
0054 - Setting LED output current
0055 - Program memory address access for running patterns
0056 - Additional device specific attributes
0057
0058 ( Firmware Interface )
0059
0060 LP55xx family devices have the internal program memory for running
0061 various LED patterns.
0062
0063 This pattern data is saved as a file in the user-land or
0064 hex byte string is written into the memory through the I2C.
0065
0066 LP55xx common driver supports the firmware interface.
0067
0068 LP55xx chips have three program engines.
0069
0070 To load and run the pattern, the programming sequence is following.
0071
0072 (1) Select an engine number (1/2/3)
0073 (2) Mode change to load
0074 (3) Write pattern data into selected area
0075 (4) Mode change to run
0076
0077 The LP55xx common driver provides simple interfaces as below.
0078
0079 select_engine:
0080 Select which engine is used for running program
0081 run_engine:
0082 Start program which is loaded via the firmware interface
0083 firmware:
0084 Load program data
0085
0086 In case of LP5523, one more command is required, 'enginex_leds'.
0087 It is used for selecting LED output(s) at each engine number.
0088 In more details, please refer to 'leds-lp5523.txt'.
0089
0090 For example, run blinking pattern in engine #1 of LP5521::
0091
0092 echo 1 > /sys/bus/i2c/devices/xxxx/select_engine
0093 echo 1 > /sys/class/firmware/lp5521/loading
0094 echo "4000600040FF6000" > /sys/class/firmware/lp5521/data
0095 echo 0 > /sys/class/firmware/lp5521/loading
0096 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
0097
0098 For example, run blinking pattern in engine #3 of LP55231
0099
0100 Two LEDs are configured as pattern output channels::
0101
0102 echo 3 > /sys/bus/i2c/devices/xxxx/select_engine
0103 echo 1 > /sys/class/firmware/lp55231/loading
0104 echo "9d0740ff7e0040007e00a0010000" > /sys/class/firmware/lp55231/data
0105 echo 0 > /sys/class/firmware/lp55231/loading
0106 echo "000001100" > /sys/bus/i2c/devices/xxxx/engine3_leds
0107 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
0108
0109 To start blinking patterns in engine #2 and #3 simultaneously::
0110
0111 for idx in 2 3
0112 do
0113 echo $idx > /sys/class/leds/red/device/select_engine
0114 sleep 0.1
0115 echo 1 > /sys/class/firmware/lp5521/loading
0116 echo "4000600040FF6000" > /sys/class/firmware/lp5521/data
0117 echo 0 > /sys/class/firmware/lp5521/loading
0118 done
0119 echo 1 > /sys/class/leds/red/device/run_engine
0120
0121 Here is another example for LP5523.
0122
0123 Full LED strings are selected by 'engine2_leds'::
0124
0125 echo 2 > /sys/bus/i2c/devices/xxxx/select_engine
0126 echo 1 > /sys/class/firmware/lp5523/loading
0127 echo "9d80400004ff05ff437f0000" > /sys/class/firmware/lp5523/data
0128 echo 0 > /sys/class/firmware/lp5523/loading
0129 echo "111111111" > /sys/bus/i2c/devices/xxxx/engine2_leds
0130 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
0131
0132 As soon as 'loading' is set to 0, registered callback is called.
0133 Inside the callback, the selected engine is loaded and memory is updated.
0134 To run programmed pattern, 'run_engine' attribute should be enabled.
0135
0136 The pattern sequence of LP8501 is similar to LP5523.
0137
0138 However pattern data is specific.
0139
0140 Ex 1) Engine 1 is used::
0141
0142 echo 1 > /sys/bus/i2c/devices/xxxx/select_engine
0143 echo 1 > /sys/class/firmware/lp8501/loading
0144 echo "9d0140ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
0145 echo 0 > /sys/class/firmware/lp8501/loading
0146 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
0147
0148 Ex 2) Engine 2 and 3 are used at the same time::
0149
0150 echo 2 > /sys/bus/i2c/devices/xxxx/select_engine
0151 sleep 1
0152 echo 1 > /sys/class/firmware/lp8501/loading
0153 echo "9d0140ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
0154 echo 0 > /sys/class/firmware/lp8501/loading
0155 sleep 1
0156 echo 3 > /sys/bus/i2c/devices/xxxx/select_engine
0157 sleep 1
0158 echo 1 > /sys/class/firmware/lp8501/loading
0159 echo "9d0340ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
0160 echo 0 > /sys/class/firmware/lp8501/loading
0161 sleep 1
0162 echo 1 > /sys/class/leds/d1/device/run_engine
0163
0164 ( 'run_engine' and 'firmware_cb' )
0165
0166 The sequence of running the program data is common.
0167
0168 But each device has own specific register addresses for commands.
0169
0170 To support this, 'run_engine' and 'firmware_cb' are configurable in each driver.
0171
0172 run_engine:
0173 Control the selected engine
0174 firmware_cb:
0175 The callback function after loading the firmware is done.
0176
0177 Chip specific commands for loading and updating program memory.
0178
0179 ( Predefined pattern data )
0180
0181 Without the firmware interface, LP55xx driver provides another method for
0182 loading a LED pattern. That is 'predefined' pattern.
0183
0184 A predefined pattern is defined in the platform data and load it(or them)
0185 via the sysfs if needed.
0186
0187 To use the predefined pattern concept, 'patterns' and 'num_patterns' should be
0188 configured.
0189
0190 Example of predefined pattern data::
0191
0192 /* mode_1: blinking data */
0193 static const u8 mode_1[] = {
0194 0x40, 0x00, 0x60, 0x00, 0x40, 0xFF, 0x60, 0x00,
0195 };
0196
0197 /* mode_2: always on */
0198 static const u8 mode_2[] = { 0x40, 0xFF, };
0199
0200 struct lp55xx_predef_pattern board_led_patterns[] = {
0201 {
0202 .r = mode_1,
0203 .size_r = ARRAY_SIZE(mode_1),
0204 },
0205 {
0206 .b = mode_2,
0207 .size_b = ARRAY_SIZE(mode_2),
0208 },
0209 }
0210
0211 struct lp55xx_platform_data lp5562_pdata = {
0212 ...
0213 .patterns = board_led_patterns,
0214 .num_patterns = ARRAY_SIZE(board_led_patterns),
0215 };
0216
0217 Then, mode_1 and mode_2 can be run via through the sysfs::
0218
0219 echo 1 > /sys/bus/i2c/devices/xxxx/led_pattern # red blinking LED pattern
0220 echo 2 > /sys/bus/i2c/devices/xxxx/led_pattern # blue LED always on
0221
0222 To stop running pattern::
0223
0224 echo 0 > /sys/bus/i2c/devices/xxxx/led_pattern
