1 =================================================
2 LP5521/LP5523/LP55231/LP5562/LP8501 Common Driver
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4
5 Authors: Milo(Woogyom) Kim <milo.kim@ti.com>
6
7 Description
8 -----------
9 LP5521, LP5523/55231, LP5562 and LP8501 have common features as below.
10
11 Register access via the I2C
12 Device initialization/deinitialization
13 Create LED class devices for multiple output channels
14 Device attributes for user-space interface
15 Program memory for running LED patterns
16
17 The LP55xx common driver provides these features using exported functions.
18
19 lp55xx_init_device() / lp55xx_deinit_device()
20 lp55xx_register_leds() / lp55xx_unregister_leds()
21 lp55xx_regsister_sysfs() / lp55xx_unregister_sysfs()
22
23 ( Driver Structure Data )
24
25 In lp55xx common driver, two different data structure is used.
26
27 * lp55xx_led
28 control multi output LED channels such as led current, channel index.
29 * lp55xx_chip
30 general chip control such like the I2C and platform data.
31
32 For example, LP5521 has maximum 3 LED channels.
33 LP5523/55231 has 9 output channels::
34
35 lp55xx_chip for LP5521 ... lp55xx_led #1
36 lp55xx_led #2
37 lp55xx_led #3
38
39 lp55xx_chip for LP5523 ... lp55xx_led #1
40 lp55xx_led #2
41 .
42 .
43 lp55xx_led #9
44
45 ( Chip Dependent Code )
46
47 To support device specific configurations, special structure
48 'lpxx_device_config' is used.
49
50 - Maximum number of channels
51 - Reset command, chip enable command
52 - Chip specific initialization
53 - Brightness control register access
54 - Setting LED output current
55 - Program memory address access for running patterns
56 - Additional device specific attributes
57
58 ( Firmware Interface )
59
60 LP55xx family devices have the internal program memory for running
61 various LED patterns.
62
63 This pattern data is saved as a file in the user-land or
64 hex byte string is written into the memory through the I2C.
65
66 LP55xx common driver supports the firmware interface.
67
68 LP55xx chips have three program engines.
69
70 To load and run the pattern, the programming sequence is following.
71
72 (1) Select an engine number (1/2/3)
73 (2) Mode change to load
74 (3) Write pattern data into selected area
75 (4) Mode change to run
76
77 The LP55xx common driver provides simple interfaces as below.
78
79 select_engine:
80 Select which engine is used for running program
81 run_engine:
82 Start program which is loaded via the firmware interface
83 firmware:
84 Load program data
85
86 In case of LP5523, one more command is required, 'enginex_leds'.
87 It is used for selecting LED output(s) at each engine number.
88 In more details, please refer to 'leds-lp5523.txt'.
89
90 For example, run blinking pattern in engine #1 of LP5521::
91
92 echo 1 > /sys/bus/i2c/devices/xxxx/select_engine
93 echo 1 > /sys/class/firmware/lp5521/loading
94 echo "4000600040FF6000" > /sys/class/firmware/lp5521/data
95 echo 0 > /sys/class/firmware/lp5521/loading
96 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
97
98 For example, run blinking pattern in engine #3 of LP55231
99
100 Two LEDs are configured as pattern output channels::
101
102 echo 3 > /sys/bus/i2c/devices/xxxx/select_engine
103 echo 1 > /sys/class/firmware/lp55231/loading
104 echo "9d0740ff7e0040007e00a0010000" > /sys/class/firmware/lp55231/data
105 echo 0 > /sys/class/firmware/lp55231/loading
106 echo "000001100" > /sys/bus/i2c/devices/xxxx/engine3_leds
107 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
108
109 To start blinking patterns in engine #2 and #3 simultaneously::
110
111 for idx in 2 3
112 do
113 echo $idx > /sys/class/leds/red/device/select_engine
114 sleep 0.1
115 echo 1 > /sys/class/firmware/lp5521/loading
116 echo "4000600040FF6000" > /sys/class/firmware/lp5521/data
117 echo 0 > /sys/class/firmware/lp5521/loading
118 done
119 echo 1 > /sys/class/leds/red/device/run_engine
120
121 Here is another example for LP5523.
122
123 Full LED strings are selected by 'engine2_leds'::
124
125 echo 2 > /sys/bus/i2c/devices/xxxx/select_engine
126 echo 1 > /sys/class/firmware/lp5523/loading
127 echo "9d80400004ff05ff437f0000" > /sys/class/firmware/lp5523/data
128 echo 0 > /sys/class/firmware/lp5523/loading
129 echo "111111111" > /sys/bus/i2c/devices/xxxx/engine2_leds
130 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
131
132 As soon as 'loading' is set to 0, registered callback is called.
133 Inside the callback, the selected engine is loaded and memory is updated.
134 To run programmed pattern, 'run_engine' attribute should be enabled.
135
136 The pattern sequence of LP8501 is similar to LP5523.
137
138 However pattern data is specific.
139
140 Ex 1) Engine 1 is used::
141
142 echo 1 > /sys/bus/i2c/devices/xxxx/select_engine
143 echo 1 > /sys/class/firmware/lp8501/loading
144 echo "9d0140ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
145 echo 0 > /sys/class/firmware/lp8501/loading
146 echo 1 > /sys/bus/i2c/devices/xxxx/run_engine
147
148 Ex 2) Engine 2 and 3 are used at the same time::
149
150 echo 2 > /sys/bus/i2c/devices/xxxx/select_engine
151 sleep 1
152 echo 1 > /sys/class/firmware/lp8501/loading
153 echo "9d0140ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
154 echo 0 > /sys/class/firmware/lp8501/loading
155 sleep 1
156 echo 3 > /sys/bus/i2c/devices/xxxx/select_engine
157 sleep 1
158 echo 1 > /sys/class/firmware/lp8501/loading
159 echo "9d0340ff7e0040007e00a001c000" > /sys/class/firmware/lp8501/data
160 echo 0 > /sys/class/firmware/lp8501/loading
161 sleep 1
162 echo 1 > /sys/class/leds/d1/device/run_engine
163
164 ( 'run_engine' and 'firmware_cb' )
165
166 The sequence of running the program data is common.
167
168 But each device has own specific register addresses for commands.
169
170 To support this, 'run_engine' and 'firmware_cb' are configurable in each driver.
171
172 run_engine:
173 Control the selected engine
174 firmware_cb:
175 The callback function after loading the firmware is done.
176
177 Chip specific commands for loading and updating program memory.
178
179 ( Predefined pattern data )
180
181 Without the firmware interface, LP55xx driver provides another method for
182 loading a LED pattern. That is 'predefined' pattern.
183
184 A predefined pattern is defined in the platform data and load it(or them)
185 via the sysfs if needed.
186
187 To use the predefined pattern concept, 'patterns' and 'num_patterns' should be
188 configured.
189
190 Example of predefined pattern data::
191
192 /* mode_1: blinking data */
193 static const u8 mode_1[] = {
194 0x40, 0x00, 0x60, 0x00, 0x40, 0xFF, 0x60, 0x00,
195 };
196
197 /* mode_2: always on */
198 static const u8 mode_2[] = { 0x40, 0xFF, };
199
200 struct lp55xx_predef_pattern board_led_patterns[] = {
201 {
202 .r = mode_1,
203 .size_r = ARRAY_SIZE(mode_1),
204 },
205 {
206 .b = mode_2,
207 .size_b = ARRAY_SIZE(mode_2),
208 },
209 }
210
211 struct lp55xx_platform_data lp5562_pdata = {
212 ...
213 .patterns = board_led_patterns,
214 .num_patterns = ARRAY_SIZE(board_led_patterns),
215 };
216
217 Then, mode_1 and mode_2 can be run via through the sysfs::
218
219 echo 1 > /sys/bus/i2c/devices/xxxx/led_pattern # red blinking LED pattern
220 echo 2 > /sys/bus/i2c/devices/xxxx/led_pattern # blue LED always on
221
222 To stop running pattern::
223
224 echo 0 > /sys/bus/i2c/devices/xxxx/led_pattern
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