1Kernel driver sht15
2===================
3
4Authors:
5  * Wouter Horre
6  * Jonathan Cameron
7  * Vivien Didelot <vivien.didelot@savoirfairelinux.com>
8  * Jerome Oufella <jerome.oufella@savoirfairelinux.com>
9
10Supported chips:
11  * Sensirion SHT10
12    Prefix: 'sht10'
13
14  * Sensirion SHT11
15    Prefix: 'sht11'
16
17  * Sensirion SHT15
18    Prefix: 'sht15'
19
20  * Sensirion SHT71
21    Prefix: 'sht71'
22
23  * Sensirion SHT75
24    Prefix: 'sht75'
25
26Datasheet: Publicly available at the Sensirion website
27http://www.sensirion.ch/en/pdf/product_information/Datasheet-humidity-sensor-SHT1x.pdf
28
29Description
30-----------
31
32The SHT10, SHT11, SHT15, SHT71, and SHT75 are humidity and temperature
33sensors.
34
35The devices communicate using two GPIO lines.
36
37Supported resolutions for the measurements are 14 bits for temperature and 12
38bits for humidity, or 12 bits for temperature and 8 bits for humidity.
39
40The humidity calibration coefficients are programmed into an OTP memory on the
41chip. These coefficients are used to internally calibrate the signals from the
42sensors. Disabling the reload of those coefficients allows saving 10ms for each
43measurement and decrease power consumption, while losing on precision.
44
45Some options may be set via sysfs attributes.
46
47Notes:
48  * The regulator supply name is set to "vcc".
49  * If a CRC validation fails, a soft reset command is sent, which resets
50    status register to its hardware default value, but the driver will try to
51    restore the previous device configuration.
52
53Platform data
54-------------
55
56* checksum:
57  set it to true to enable CRC validation of the readings (default to false).
58* no_otp_reload:
59  flag to indicate not to reload from OTP (default to false).
60* low_resolution:
61  flag to indicate the temp/humidity resolution to use (default to false).
62
63Sysfs interface
64---------------
65
66* temp1_input:     temperature input
67* humidity1_input: humidity input
68* heater_enable:   write 1 in this attribute to enable the on-chip heater,
69                   0 to disable it. Be careful not to enable the heater
70                   for too long.
71* temp1_fault:     if 1, this means that the voltage is low (below 2.47V) and
72                   measurement may be invalid.
73* humidity1_fault: same as temp1_fault.
74