1 LP5521/LP5523/LP55231/LP5562/LP8501 Common Driver
2 =================================================
4 Authors: Milo(Woogyom) Kim <milo.kim@ti.com>
8 LP5521, LP5523/55231, LP5562 and LP8501 have common features as below.
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
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()
21 ( Driver Structure Data )
23 In lp55xx common driver, two different data structure is used.
26 control multi output LED channels such as led current, channel index.
28 general chip control such like the I2C and platform data.
30 For example, LP5521 has maximum 3 LED channels.
31 LP5523/55231 has 9 output channels.
33 lp55xx_chip for LP5521 ... lp55xx_led #1
37 lp55xx_chip for LP5523 ... lp55xx_led #1
43 ( Chip Dependent Code )
45 To support device specific configurations, special structure
46 'lpxx_device_config' is used.
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
56 ( Firmware Interface )
58 LP55xx family devices have the internal program memory for running
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.
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
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
76 For example, run blinking pattern in engine #1 of LP5521
77 echo 1 > /sys/bus/i2c/devices/xxxx/select_engine
78 echo 1 > /sys/class/firmware/lp5521/loading
79 echo "4000600040FF6000" > /sys/class/firmware/lp5521/data
80 echo 0 > /sys/class/firmware/lp5521/loading
81 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
83 For example, run blinking pattern in engine #3 of LP55231
84 echo 3 > /sys/bus/i2c/devices/xxxx/select_engine
85 echo 1 > /sys/class/firmware/lp55231/loading
86 echo "9d0740ff7e0040007e00a0010000" > /sys/class/firmware/lp55231/data
87 echo 0 > /sys/class/firmware/lp55231/loading
88 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
90 To start blinking patterns in engine #2 and #3 simultaneously,
93 echo $idx > /sys/class/leds/red/device/select_engine
95 echo 1 > /sys/class/firmware/lp5521/loading
96 echo "4000600040FF6000" > /sys/class/firmware/lp5521/data
97 echo 0 > /sys/class/firmware/lp5521/loading
99 echo 1 > /sys/class/leds/red/device/run_engine
101 Here is another example for LP5523.
102 echo 2 > /sys/bus/i2c/devices/xxxx/select_engine
103 echo 1 > /sys/class/firmware/lp5523/loading
104 echo "9d80400004ff05ff437f0000" > /sys/class/firmware/lp5523/data
105 echo 0 > /sys/class/firmware/lp5523/loading
106 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
108 As soon as 'loading' is set to 0, registered callback is called.
109 Inside the callback, the selected engine is loaded and memory is updated.
110 To run programmed pattern, 'run_engine' attribute should be enabled.
112 The pattern sqeuence of LP8501 is same as LP5523.
113 However pattern data is specific.
114 Ex 1) Engine 1 is used
115 echo 1 > /sys/bus/i2c/devices/xxxx/select_engine
116 echo 1 > /sys/class/firmware/lp8501/loading
117 echo "9d0140ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
118 echo 0 > /sys/class/firmware/lp8501/loading
119 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
121 Ex 2) Engine 2 and 3 are used at the same time
122 echo 2 > /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
128 echo 3 > /sys/bus/i2c/devices/xxxx/select_engine
130 echo 1 > /sys/class/firmware/lp8501/loading
131 echo "9d0340ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
132 echo 0 > /sys/class/firmware/lp8501/loading
134 echo 1 > /sys/class/leds/d1/device/run_engine
136 ( 'run_engine' and 'firmware_cb' )
137 The sequence of running the program data is common.
138 But each device has own specific register addresses for commands.
139 To support this, 'run_engine' and 'firmware_cb' are configurable in each driver.
140 run_engine : Control the selected engine
141 firmware_cb : The callback function after loading the firmware is done.
142 Chip specific commands for loading and updating program memory.
144 ( Predefined pattern data )
146 Without the firmware interface, LP55xx driver provides another method for
147 loading a LED pattern. That is 'predefined' pattern.
148 A predefined pattern is defined in the platform data and load it(or them)
149 via the sysfs if needed.
150 To use the predefined pattern concept, 'patterns' and 'num_patterns' should be
153 Example of predefined pattern data:
155 /* mode_1: blinking data */
156 static const u8 mode_1[] = {
157 0x40, 0x00, 0x60, 0x00, 0x40, 0xFF, 0x60, 0x00,
160 /* mode_2: always on */
161 static const u8 mode_2[] = { 0x40, 0xFF, };
163 struct lp55xx_predef_pattern board_led_patterns[] = {
166 .size_r = ARRAY_SIZE(mode_1),
170 .size_b = ARRAY_SIZE(mode_2),
174 struct lp55xx_platform_data lp5562_pdata = {
176 .patterns = board_led_patterns,
177 .num_patterns = ARRAY_SIZE(board_led_patterns),
180 Then, mode_1 and mode_2 can be run via through the sysfs.
182 echo 1 > /sys/bus/i2c/devices/xxxx/led_pattern # red blinking LED pattern
183 echo 2 > /sys/bus/i2c/devices/xxxx/led_pattern # blue LED always on
185 To stop running pattern,
186 echo 0 > /sys/bus/i2c/devices/xxxx/led_pattern