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2 | Kernel driver for lm3556 |
3 | ======================== | |
4 | ||
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5 | * Texas Instrument: |
6 | 1.5 A Synchronous Boost LED Flash Driver w/ High-Side Current Source | |
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7 | * Datasheet: http://www.national.com/ds/LM/LM3556.pdf |
8 | ||
9 | Authors: | |
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10 | - Daniel Jeong |
11 | ||
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12 | Contact:Daniel Jeong(daniel.jeong-at-ti.com, gshark.jeong-at-gmail.com) |
13 | ||
14 | Description | |
15 | ----------- | |
16 | There are 3 functions in LM3556, Flash, Torch and Indicator. | |
17 | ||
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18 | Flash Mode |
19 | ^^^^^^^^^^ | |
20 | ||
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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 are adjusted via the CURRENT | |
23 | CONTROL REGISTER(0x09).Flash mode is activated by the ENABLE REGISTER(0x0A), | |
24 | or by pulling the STROBE pin HIGH. | |
8dab9197 | 25 | |
abb9c078 | 26 | LM3556 Flash can be controlled through /sys/class/leds/flash/brightness file |
8dab9197 | 27 | |
32abb478 | 28 | * if STROBE pin is enabled, below example control brightness only, and |
8dab9197 | 29 | ON / OFF will be controlled by STROBE pin. |
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30 | |
31 | Flash Example: | |
32abb478 | 32 | |
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33 | OFF:: |
34 | ||
abb9c078 | 35 | #echo 0 > /sys/class/leds/flash/brightness |
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36 | |
37 | 93.75 mA:: | |
38 | ||
abb9c078 | 39 | #echo 1 > /sys/class/leds/flash/brightness |
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40 | |
41 | ... | |
42 | ||
43 | 1500 mA:: | |
44 | ||
abb9c078 | 45 | #echo 16 > /sys/class/leds/flash/brightness |
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46 | |
47 | Torch Mode | |
48 | ^^^^^^^^^^ | |
49 | ||
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50 | In Torch Mode, the current source(LED) is programmed via the CURRENT CONTROL |
51 | REGISTER(0x09).Torch Mode is activated by the ENABLE REGISTER(0x0A) or by the | |
52 | hardware TORCH input. | |
8dab9197 | 53 | |
abb9c078 | 54 | LM3556 torch can be controlled through /sys/class/leds/torch/brightness file. |
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55 | * if TORCH pin is enabled, below example control brightness only, |
56 | and ON / OFF will be controlled by TORCH pin. | |
57 | ||
58 | Torch Example: | |
32abb478 | 59 | |
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60 | OFF:: |
61 | ||
abb9c078 | 62 | #echo 0 > /sys/class/leds/torch/brightness |
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63 | |
64 | 46.88 mA:: | |
65 | ||
abb9c078 | 66 | #echo 1 > /sys/class/leds/torch/brightness |
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67 | |
68 | ... | |
69 | ||
70 | 375 mA:: | |
71 | ||
abb9c078 | 72 | #echo 8 > /sys/class/leds/torch/brightness |
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73 | |
74 | Indicator Mode | |
75 | ^^^^^^^^^^^^^^ | |
76 | ||
abb9c078 | 77 | Indicator pattern can be set through /sys/class/leds/indicator/pattern file, |
32abb478 | 78 | and 4 patterns are pre-defined in indicator_pattern array. |
8dab9197 | 79 | |
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80 | According to N-lank, Pulse time and N Period values, different pattern wiill |
81 | be generated.If you want new patterns for your own device, change | |
82 | indicator_pattern array with your own values and INDIC_PATTERN_SIZE. | |
8dab9197 | 83 | |
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84 | Please refer datasheet for more detail about N-Blank, Pulse time and N Period. |
85 | ||
86 | Indicator pattern example: | |
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87 | |
88 | pattern 0:: | |
89 | ||
abb9c078 | 90 | #echo 0 > /sys/class/leds/indicator/pattern |
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91 | |
92 | ... | |
93 | ||
94 | pattern 3:: | |
95 | ||
abb9c078 | 96 | #echo 3 > /sys/class/leds/indicator/pattern |
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97 | |
98 | Indicator brightness can be controlled through | |
99 | sys/class/leds/indicator/brightness file. | |
100 | ||
101 | Example: | |
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102 | |
103 | OFF:: | |
104 | ||
abb9c078 | 105 | #echo 0 > /sys/class/leds/indicator/brightness |
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106 | |
107 | 5.86 mA:: | |
108 | ||
abb9c078 | 109 | #echo 1 > /sys/class/leds/indicator/brightness |
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110 | |
111 | ... | |
112 | ||
113 | 46.875mA:: | |
114 | ||
abb9c078 | 115 | #echo 8 > /sys/class/leds/indicator/brightness |
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116 | |
117 | Notes | |
118 | ----- | |
119 | Driver expects it is registered using the i2c_board_info mechanism. | |
120 | To register the chip at address 0x63 on specific adapter, set the platform data | |
121 | according to include/linux/platform_data/leds-lm3556.h, set the i2c board info | |
122 | ||
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123 | Example:: |
124 | ||
eb967b6a | 125 | static struct i2c_board_info board_i2c_ch4[] __initdata = { |
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126 | { |
127 | I2C_BOARD_INFO(LM3556_NAME, 0x63), | |
128 | .platform_data = &lm3556_pdata, | |
129 | }, | |
130 | }; | |
131 | ||
132 | and register it in the platform init function | |
133 | ||
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134 | Example:: |
135 | ||
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136 | board_register_i2c_bus(4, 400, |
137 | board_i2c_ch4, ARRAY_SIZE(board_i2c_ch4)); |