1 .. SPDX-License-Identifier: GPL-2.0 1 .. SPDX-License-Identifier: GPL-2.0
2 2
3 ======================= 3 =======================
4 Kernel driver bh1770glc 4 Kernel driver bh1770glc
5 ======================= 5 =======================
6 6
7 Supported chips: 7 Supported chips:
8 8
9 - ROHM BH1770GLC 9 - ROHM BH1770GLC
10 - OSRAM SFH7770 10 - OSRAM SFH7770
11 11
12 Data sheet: 12 Data sheet:
13 Not freely available 13 Not freely available
14 14
15 Author: 15 Author:
16 Samu Onkalo <samu.p.onkalo@nokia.com> 16 Samu Onkalo <samu.p.onkalo@nokia.com>
17 17
18 Description 18 Description
19 ----------- 19 -----------
20 BH1770GLC and SFH7770 are combined ambient lig 20 BH1770GLC and SFH7770 are combined ambient light and proximity sensors.
21 ALS and proximity parts operates on their own, 21 ALS and proximity parts operates on their own, but they shares common I2C
22 interface and interrupt logic. In principle th 22 interface and interrupt logic. In principle they can run on their own,
23 but ALS side results are used to estimate reli 23 but ALS side results are used to estimate reliability of the proximity sensor.
24 24
25 ALS produces 16 bit lux values. The chip conta 25 ALS produces 16 bit lux values. The chip contains interrupt logic to produce
26 low and high threshold interrupts. 26 low and high threshold interrupts.
27 27
28 Proximity part contains IR-led driver up to 3 28 Proximity part contains IR-led driver up to 3 IR leds. The chip measures
29 amount of reflected IR light and produces prox 29 amount of reflected IR light and produces proximity result. Resolution is
30 8 bit. Driver supports only one channel. Drive 30 8 bit. Driver supports only one channel. Driver uses ALS results to estimate
31 reliability of the proximity results. Thus ALS 31 reliability of the proximity results. Thus ALS is always running while
32 proximity detection is needed. 32 proximity detection is needed.
33 33
34 Driver uses threshold interrupts to avoid need 34 Driver uses threshold interrupts to avoid need for polling the values.
35 Proximity low interrupt doesn't exists in the 35 Proximity low interrupt doesn't exists in the chip. This is simulated
36 by using a delayed work. As long as there is p 36 by using a delayed work. As long as there is proximity threshold above
37 interrupts the delayed work is pushed forward. 37 interrupts the delayed work is pushed forward. So, when proximity level goes
38 below the threshold value, there is no interru 38 below the threshold value, there is no interrupt and the delayed work will
39 finally run. This is handled as no proximity i 39 finally run. This is handled as no proximity indication.
40 40
41 Chip state is controlled via runtime pm framew 41 Chip state is controlled via runtime pm framework when enabled in config.
42 42
43 Calibscale factor is used to hide differences 43 Calibscale factor is used to hide differences between the chips. By default
44 value set to neutral state meaning factor of 1 44 value set to neutral state meaning factor of 1.00. To get proper values,
45 calibrated source of light is needed as a refe 45 calibrated source of light is needed as a reference. Calibscale factor is set
46 so that measurement produces about the expecte 46 so that measurement produces about the expected lux value.
47 47
48 SYSFS 48 SYSFS
49 ----- 49 -----
50 50
51 chip_id 51 chip_id
52 RO - shows detected chip type and vers 52 RO - shows detected chip type and version
53 53
54 power_state 54 power_state
55 RW - enable / disable chip 55 RW - enable / disable chip
56 56
57 Uses counting logic 57 Uses counting logic
58 58
59 - 1 enables the chip 59 - 1 enables the chip
60 - 0 disables the chip 60 - 0 disables the chip
61 61
62 lux0_input 62 lux0_input
63 RO - measured lux value 63 RO - measured lux value
64 64
65 sysfs_notify called when threshol 65 sysfs_notify called when threshold interrupt occurs
66 66
67 lux0_sensor_range 67 lux0_sensor_range
68 RO - lux0_input max value 68 RO - lux0_input max value
69 69
70 lux0_rate 70 lux0_rate
71 RW - measurement rate in Hz 71 RW - measurement rate in Hz
72 72
73 lux0_rate_avail 73 lux0_rate_avail
74 RO - supported measurement rates 74 RO - supported measurement rates
75 75
76 lux0_thresh_above_value 76 lux0_thresh_above_value
77 RW - HI level threshold value 77 RW - HI level threshold value
78 78
79 All results above the value 79 All results above the value
80 trigs an interrupt. 65535 (i.e. s 80 trigs an interrupt. 65535 (i.e. sensor_range) disables the above
81 interrupt. 81 interrupt.
82 82
83 lux0_thresh_below_value 83 lux0_thresh_below_value
84 RW - LO level threshold value 84 RW - LO level threshold value
85 85
86 All results below the value 86 All results below the value
87 trigs an interrupt. 0 disables th 87 trigs an interrupt. 0 disables the below interrupt.
88 88
89 lux0_calibscale 89 lux0_calibscale
90 RW - calibration value 90 RW - calibration value
91 91
92 Set to neutral value by default. 92 Set to neutral value by default.
93 Output results are multiplied wit 93 Output results are multiplied with calibscale / calibscale_default
94 value. 94 value.
95 95
96 lux0_calibscale_default 96 lux0_calibscale_default
97 RO - neutral calibration value 97 RO - neutral calibration value
98 98
99 prox0_raw 99 prox0_raw
100 RO - measured proximity value 100 RO - measured proximity value
101 101
102 sysfs_notify called when threshol 102 sysfs_notify called when threshold interrupt occurs
103 103
104 prox0_sensor_range 104 prox0_sensor_range
105 RO - prox0_raw max value 105 RO - prox0_raw max value
106 106
107 prox0_raw_en 107 prox0_raw_en
108 RW - enable / disable proximity 108 RW - enable / disable proximity
109 109
110 Uses counting logic 110 Uses counting logic
111 111
112 - 1 enables the proximity 112 - 1 enables the proximity
113 - 0 disables the proximity 113 - 0 disables the proximity
114 114
115 prox0_thresh_above_count 115 prox0_thresh_above_count
116 RW - number of proximity interrupts ne 116 RW - number of proximity interrupts needed before triggering the event
117 117
118 prox0_rate_above 118 prox0_rate_above
119 RW - Measurement rate (in Hz) when the 119 RW - Measurement rate (in Hz) when the level is above threshold
120 i.e. when proximity on has been report 120 i.e. when proximity on has been reported.
121 121
122 prox0_rate_below 122 prox0_rate_below
123 RW - Measurement rate (in Hz) when the 123 RW - Measurement rate (in Hz) when the level is below threshold
124 i.e. when proximity off has been repor 124 i.e. when proximity off has been reported.
125 125
126 prox0_rate_avail 126 prox0_rate_avail
127 RO - Supported proximity measurement r 127 RO - Supported proximity measurement rates in Hz
128 128
129 prox0_thresh_above0_value 129 prox0_thresh_above0_value
130 RW - threshold level which trigs proxi 130 RW - threshold level which trigs proximity events.
131 131
132 Filtered by persistence filter (p 132 Filtered by persistence filter (prox0_thresh_above_count)
133 133
134 prox0_thresh_above1_value 134 prox0_thresh_above1_value
135 RW - threshold level which trigs event 135 RW - threshold level which trigs event immediately
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