1.. SPDX-License-Identifier: GPL-2.0-or-later 2 3Kernel driver ChipCap2 4====================== 5 6Supported chips: 7 8 * Amphenol CC2D23, CC2D23S, CC2D25, CC2D25S, CC2D33, CC2D33S, CC2D35, CC2D35S 9 10 Prefix: 'chipcap2' 11 12 Addresses scanned: - 13 14 Datasheet: https://www.amphenol-sensors.com/en/telaire/humidity/527-humidity-sensors/3095-chipcap-2 15 16Author: 17 18 - Javier Carrasco <javier.carrasco.cruz@gmail.com> 19 20Description 21----------- 22 23This driver implements support for the Amphenol ChipCap 2, a humidity and 24temperature chip family. Temperature is measured in milli degrees celsius, 25relative humidity is expressed as a per cent mille. The measurement ranges 26are the following: 27 28 - Relative humidity: 0 to 100000 pcm (14-bit resolution) 29 - Temperature: -40000 to +125000 m°C (14-bit resolution) 30 31The device communicates with the I2C protocol and uses the I2C address 0x28 32by default. 33 34Depending on the hardware configuration, up to two humidity alarms to control 35minimum and maximum values are provided. Their thresholds and hystersis can be 36configured via sysfs. 37 38Thresholds and hysteris must be provided as a per cent mille. These values 39might be truncated to match the 14-bit device resolution (6.1 pcm/LSB) 40 41Known Issues 42------------ 43 44The driver does not support I2C address and command window length modification. 45 46sysfs-Interface 47--------------- 48 49The following list includes the sysfs attributes that the driver always provides, 50their permissions and a short description: 51 52=============================== ======= ======================================== 53Name Perm Description 54=============================== ======= ======================================== 55temp1_input: RO temperature input 56humidity1_input: RO humidity input 57=============================== ======= ======================================== 58 59The following list includes the sysfs attributes that the driver may provide 60depending on the hardware configuration: 61 62=============================== ======= ======================================== 63Name Perm Description 64=============================== ======= ======================================== 65humidity1_min: RW humidity low limit. Measurements under 66 this limit trigger a humidity low alarm 67humidity1_max: RW humidity high limit. Measurements above 68 this limit trigger a humidity high alarm 69humidity1_min_hyst: RW humidity low hystersis 70humidity1_max_hyst: RW humidity high hystersis 71humidity1_min_alarm: RO humidity low alarm indicator 72humidity1_max_alarm: RO humidity high alarm indicator 73=============================== ======= ======================================== 74