1Kernel driver sht15
2===================
3
4Authors:
5
6  * Wouter Horre
7  * Jonathan Cameron
8  * Vivien Didelot <vivien.didelot@savoirfairelinux.com>
9  * Jerome Oufella <jerome.oufella@savoirfairelinux.com>
10
11Supported chips:
12
13  * Sensirion SHT10
14
15    Prefix: 'sht10'
16
17  * Sensirion SHT11
18
19    Prefix: 'sht11'
20
21  * Sensirion SHT15
22
23    Prefix: 'sht15'
24
25  * Sensirion SHT71
26
27    Prefix: 'sht71'
28
29  * Sensirion SHT75
30
31    Prefix: 'sht75'
32
33Datasheet: Publicly available at the Sensirion website
34
35	http://www.sensirion.ch/en/pdf/product_information/Datasheet-humidity-sensor-SHT1x.pdf
36
37Description
38-----------
39
40The SHT10, SHT11, SHT15, SHT71, and SHT75 are humidity and temperature
41sensors.
42
43The devices communicate using two GPIO lines.
44
45Supported resolutions for the measurements are 14 bits for temperature and 12
46bits for humidity, or 12 bits for temperature and 8 bits for humidity.
47
48The humidity calibration coefficients are programmed into an OTP memory on the
49chip. These coefficients are used to internally calibrate the signals from the
50sensors. Disabling the reload of those coefficients allows saving 10ms for each
51measurement and decrease power consumption, while losing on precision.
52
53Some options may be set via sysfs attributes.
54
55Notes:
56  * The regulator supply name is set to "vcc".
57  * If a CRC validation fails, a soft reset command is sent, which resets
58    status register to its hardware default value, but the driver will try to
59    restore the previous device configuration.
60
61Platform data
62-------------
63
64* checksum:
65  set it to true to enable CRC validation of the readings (default to false).
66* no_otp_reload:
67  flag to indicate not to reload from OTP (default to false).
68* low_resolution:
69  flag to indicate the temp/humidity resolution to use (default to false).
70
71Sysfs interface
72---------------
73
74================== ==========================================================
75temp1_input        temperature input
76humidity1_input    humidity input
77heater_enable      write 1 in this attribute to enable the on-chip heater,
78		   0 to disable it. Be careful not to enable the heater
79		   for too long.
80temp1_fault        if 1, this means that the voltage is low (below 2.47V) and
81		   measurement may be invalid.
82humidity1_fault    same as temp1_fault.
83================== ==========================================================
84