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- .. SPDX-License-Identifier: GPL-2.0-or-later
- Kernel driver ChipCap2
- ======================
- Supported chips:
- * Amphenol CC2D23, CC2D23S, CC2D25, CC2D25S, CC2D33, CC2D33S, CC2D35, CC2D35S
- Prefix: 'chipcap2'
- Addresses scanned: -
- Datasheet: https://www.amphenol-sensors.com/en/telaire/humidity/527-humidity-sensors/3095-chipcap-2
- Author:
- - Javier Carrasco <javier.carrasco.cruz@gmail.com>
- Description
- -----------
- This driver implements support for the Amphenol ChipCap 2, a humidity and
- temperature chip family. Temperature is measured in milli degrees celsius,
- relative humidity is expressed as a per cent mille. The measurement ranges
- are the following:
- - Relative humidity: 0 to 100000 pcm (14-bit resolution)
- - Temperature: -40000 to +125000 m°C (14-bit resolution)
- The device communicates with the I2C protocol and uses the I2C address 0x28
- by default.
- Depending on the hardware configuration, up to two humidity alarms to control
- minimum and maximum values are provided. Their thresholds and hystersis can be
- configured via sysfs.
- Thresholds and hysteris must be provided as a per cent mille. These values
- might be truncated to match the 14-bit device resolution (6.1 pcm/LSB)
- Known Issues
- ------------
- The driver does not support I2C address and command window length modification.
- sysfs-Interface
- ---------------
- The following list includes the sysfs attributes that the driver always provides,
- their permissions and a short description:
- =============================== ======= ========================================
- Name Perm Description
- =============================== ======= ========================================
- temp1_input: RO temperature input
- humidity1_input: RO humidity input
- =============================== ======= ========================================
- The following list includes the sysfs attributes that the driver may provide
- depending on the hardware configuration:
- =============================== ======= ========================================
- Name Perm Description
- =============================== ======= ========================================
- humidity1_min: RW humidity low limit. Measurements under
- this limit trigger a humidity low alarm
- humidity1_max: RW humidity high limit. Measurements above
- this limit trigger a humidity high alarm
- humidity1_min_hyst: RW humidity low hystersis
- humidity1_max_hyst: RW humidity high hystersis
- humidity1_min_alarm: RO humidity low alarm indicator
- humidity1_max_alarm: RO humidity high alarm indicator
- =============================== ======= ========================================
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