1Kernel driver bh1770glc 2======================= 3 4Supported chips: 5ROHM BH1770GLC 6OSRAM SFH7770 7 8Data sheet: 9Not freely available 10 11Author: 12Samu Onkalo <samu.p.onkalo@nokia.com> 13 14Description 15----------- 16BH1770GLC and SFH7770 are combined ambient light and proximity sensors. 17ALS and proximity parts operates on their own, but they shares common I2C 18interface and interrupt logic. In principle they can run on their own, 19but ALS side results are used to estimate reliability of the proximity sensor. 20 21ALS produces 16 bit lux values. The chip contains interrupt logic to produce 22low and high threshold interrupts. 23 24Proximity part contains IR-led driver up to 3 IR leds. The chip measures 25amount of reflected IR light and produces proximity result. Resolution is 268 bit. Driver supports only one channel. Driver uses ALS results to estimate 27reliability of the proximity results. Thus ALS is always running while 28proximity detection is needed. 29 30Driver uses threshold interrupts to avoid need for polling the values. 31Proximity low interrupt doesn't exists in the chip. This is simulated 32by using a delayed work. As long as there is proximity threshold above 33interrupts the delayed work is pushed forward. So, when proximity level goes 34below the threshold value, there is no interrupt and the delayed work will 35finally run. This is handled as no proximity indication. 36 37Chip state is controlled via runtime pm framework when enabled in config. 38 39Calibscale factor is used to hide differences between the chips. By default 40value set to neutral state meaning factor of 1.00. To get proper values, 41calibrated source of light is needed as a reference. Calibscale factor is set 42so that measurement produces about the expected lux value. 43 44SYSFS 45----- 46 47chip_id 48 RO - shows detected chip type and version 49 50power_state 51 RW - enable / disable chip. Uses counting logic 52 1 enables the chip 53 0 disables the chip 54 55lux0_input 56 RO - measured lux value 57 sysfs_notify called when threshold interrupt occurs 58 59lux0_sensor_range 60 RO - lux0_input max value 61 62lux0_rate 63 RW - measurement rate in Hz 64 65lux0_rate_avail 66 RO - supported measurement rates 67 68lux0_thresh_above_value 69 RW - HI level threshold value. All results above the value 70 trigs an interrupt. 65535 (i.e. sensor_range) disables the above 71 interrupt. 72 73lux0_thresh_below_value 74 RW - LO level threshold value. All results below the value 75 trigs an interrupt. 0 disables the below interrupt. 76 77lux0_calibscale 78 RW - calibration value. Set to neutral value by default. 79 Output results are multiplied with calibscale / calibscale_default 80 value. 81 82lux0_calibscale_default 83 RO - neutral calibration value 84 85prox0_raw 86 RO - measured proximity value 87 sysfs_notify called when threshold interrupt occurs 88 89prox0_sensor_range 90 RO - prox0_raw max value 91 92prox0_raw_en 93 RW - enable / disable proximity - uses counting logic 94 1 enables the proximity 95 0 disables the proximity 96 97prox0_thresh_above_count 98 RW - number of proximity interrupts needed before triggering the event 99 100prox0_rate_above 101 RW - Measurement rate (in Hz) when the level is above threshold 102 i.e. when proximity on has been reported. 103 104prox0_rate_below 105 RW - Measurement rate (in Hz) when the level is below threshold 106 i.e. when proximity off has been reported. 107 108prox0_rate_avail 109 RO - Supported proximity measurement rates in Hz 110 111prox0_thresh_above0_value 112 RW - threshold level which trigs proximity events. 113 Filtered by persistence filter (prox0_thresh_above_count) 114 115prox0_thresh_above1_value 116 RW - threshold level which trigs event immediately 117