1 ======================== 1 ========================
2 Kernel driver for lm3556 2 Kernel driver for lm3556
3 ======================== 3 ========================
4 4
5 * Texas Instrument: 5 * Texas Instrument:
6 1.5 A Synchronous Boost LED Flash Driver w/ 6 1.5 A Synchronous Boost LED Flash Driver w/ High-Side Current Source
7 * Datasheet: http://www.national.com/ds/LM/LM3 7 * Datasheet: http://www.national.com/ds/LM/LM3556.pdf
8 8
9 Authors: 9 Authors:
10 - Daniel Jeong 10 - Daniel Jeong
11 11
12 Contact:Daniel Jeong(daniel.jeong-at-t 12 Contact:Daniel Jeong(daniel.jeong-at-ti.com, gshark.jeong-at-gmail.com)
13 13
14 Description 14 Description
15 ----------- 15 -----------
16 There are 3 functions in LM3556, Flash, Torch 16 There are 3 functions in LM3556, Flash, Torch and Indicator.
17 17
18 Flash Mode 18 Flash Mode
19 ^^^^^^^^^^ 19 ^^^^^^^^^^
20 20
21 In Flash Mode, the LED current source(LED) pro 21 In Flash Mode, the LED current source(LED) provides 16 target current levels
22 from 93.75 mA to 1500 mA.The Flash currents ar 22 from 93.75 mA to 1500 mA.The Flash currents are adjusted via the CURRENT
23 CONTROL REGISTER(0x09).Flash mode is activated 23 CONTROL REGISTER(0x09).Flash mode is activated by the ENABLE REGISTER(0x0A),
24 or by pulling the STROBE pin HIGH. 24 or by pulling the STROBE pin HIGH.
25 25
26 LM3556 Flash can be controlled through /sys/cl 26 LM3556 Flash can be controlled through /sys/class/leds/flash/brightness file
27 27
28 * if STROBE pin is enabled, below example cont 28 * if STROBE pin is enabled, below example control brightness only, and
29 ON / OFF will be controlled by STROBE pin. 29 ON / OFF will be controlled by STROBE pin.
30 30
31 Flash Example: 31 Flash Example:
32 32
33 OFF:: 33 OFF::
34 34
35 #echo 0 > /sys/class/leds/flash/bright 35 #echo 0 > /sys/class/leds/flash/brightness
36 36
37 93.75 mA:: 37 93.75 mA::
38 38
39 #echo 1 > /sys/class/leds/flash/bright 39 #echo 1 > /sys/class/leds/flash/brightness
40 40
41 ... 41 ...
42 42
43 1500 mA:: 43 1500 mA::
44 44
45 #echo 16 > /sys/class/leds/flash/brigh 45 #echo 16 > /sys/class/leds/flash/brightness
46 46
47 Torch Mode 47 Torch Mode
48 ^^^^^^^^^^ 48 ^^^^^^^^^^
49 49
50 In Torch Mode, the current source(LED) is prog 50 In Torch Mode, the current source(LED) is programmed via the CURRENT CONTROL
51 REGISTER(0x09).Torch Mode is activated by the 51 REGISTER(0x09).Torch Mode is activated by the ENABLE REGISTER(0x0A) or by the
52 hardware TORCH input. 52 hardware TORCH input.
53 53
54 LM3556 torch can be controlled through /sys/cl 54 LM3556 torch can be controlled through /sys/class/leds/torch/brightness file.
55 * if TORCH pin is enabled, below example contr 55 * if TORCH pin is enabled, below example control brightness only,
56 and ON / OFF will be controlled by TORCH pin. 56 and ON / OFF will be controlled by TORCH pin.
57 57
58 Torch Example: 58 Torch Example:
59 59
60 OFF:: 60 OFF::
61 61
62 #echo 0 > /sys/class/leds/torch/bright 62 #echo 0 > /sys/class/leds/torch/brightness
63 63
64 46.88 mA:: 64 46.88 mA::
65 65
66 #echo 1 > /sys/class/leds/torch/bright 66 #echo 1 > /sys/class/leds/torch/brightness
67 67
68 ... 68 ...
69 69
70 375 mA:: 70 375 mA::
71 71
72 #echo 8 > /sys/class/leds/torch/bright 72 #echo 8 > /sys/class/leds/torch/brightness
73 73
74 Indicator Mode 74 Indicator Mode
75 ^^^^^^^^^^^^^^ 75 ^^^^^^^^^^^^^^
76 76
77 Indicator pattern can be set through /sys/clas 77 Indicator pattern can be set through /sys/class/leds/indicator/pattern file,
78 and 4 patterns are pre-defined in indicator_pa 78 and 4 patterns are pre-defined in indicator_pattern array.
79 79
80 According to N-lank, Pulse time and N Period v 80 According to N-lank, Pulse time and N Period values, different pattern wiill
81 be generated.If you want new patterns for your 81 be generated.If you want new patterns for your own device, change
82 indicator_pattern array with your own values a 82 indicator_pattern array with your own values and INDIC_PATTERN_SIZE.
83 83
84 Please refer datasheet for more detail about N 84 Please refer datasheet for more detail about N-Blank, Pulse time and N Period.
85 85
86 Indicator pattern example: 86 Indicator pattern example:
87 87
88 pattern 0:: 88 pattern 0::
89 89
90 #echo 0 > /sys/class/leds/indicator/pa 90 #echo 0 > /sys/class/leds/indicator/pattern
91 91
92 ... 92 ...
93 93
94 pattern 3:: 94 pattern 3::
95 95
96 #echo 3 > /sys/class/leds/indicator/pa 96 #echo 3 > /sys/class/leds/indicator/pattern
97 97
98 Indicator brightness can be controlled through 98 Indicator brightness can be controlled through
99 sys/class/leds/indicator/brightness file. 99 sys/class/leds/indicator/brightness file.
100 100
101 Example: 101 Example:
102 102
103 OFF:: 103 OFF::
104 104
105 #echo 0 > /sys/class/leds/indicator/br 105 #echo 0 > /sys/class/leds/indicator/brightness
106 106
107 5.86 mA:: 107 5.86 mA::
108 108
109 #echo 1 > /sys/class/leds/indicator/br 109 #echo 1 > /sys/class/leds/indicator/brightness
110 110
111 ... 111 ...
112 112
113 46.875mA:: 113 46.875mA::
114 114
115 #echo 8 > /sys/class/leds/indicator/br 115 #echo 8 > /sys/class/leds/indicator/brightness
116 116
117 Notes 117 Notes
118 ----- 118 -----
119 Driver expects it is registered using the i2c_ 119 Driver expects it is registered using the i2c_board_info mechanism.
120 To register the chip at address 0x63 on specif 120 To register the chip at address 0x63 on specific adapter, set the platform data
121 according to include/linux/platform_data/leds- 121 according to include/linux/platform_data/leds-lm3556.h, set the i2c board info
122 122
123 Example:: 123 Example::
124 124
125 static struct i2c_board_info board_i2c 125 static struct i2c_board_info board_i2c_ch4[] __initdata = {
126 { 126 {
127 I2C_BOARD_INFO(LM3556 127 I2C_BOARD_INFO(LM3556_NAME, 0x63),
128 .platform_data = &lm3 128 .platform_data = &lm3556_pdata,
129 }, 129 },
130 }; 130 };
131 131
132 and register it in the platform init function 132 and register it in the platform init function
133 133
134 Example:: 134 Example::
135 135
136 board_register_i2c_bus(4, 400, 136 board_register_i2c_bus(4, 400,
137 board_i2c_ch4, 137 board_i2c_ch4, ARRAY_SIZE(board_i2c_ch4));
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.