This version (15 Nov 2022 14:57) was approved by Cosmin Tanislav.The Previously approved version (07 Jan 2020 13:45) is available.
Table of Contents
LTC2983/LTC2984/LTC2986/LTM2985 Multi-Sensor Digital Temperature Measurement System Driver
Supported Devices
Evaluation Boards
Description
This is a Linux industrial I/O (IIO) subsystem driver, targeting temperature sensors. The industrial I/O subsystem provides a unified framework for drivers for many different types of converters and sensors using a number of different physical interfaces (i2c, spi, etc). See IIO for more information.
Source Code
Status
| Source | Mainlined? |
|---|---|
| drivers/iio/temperature/ltc2983.c | yes |
Files
| Function | File |
|---|---|
| driver | drivers/iio/temperature/ltc2983.c |
| Documentation | adi,ltc2983.yaml |
Example SPI device initialization
The devices can only be instantiated via device tree, along with all the sensors attached to it.
Adding Linux driver support
Configure kernel with “make menuconfig” (alternatively use “make xconfig” or “make qconfig”).
The LTC2983 driver depends CONFIG_SPI.
Linux Kernel Configuration
Device Drivers --->
<*> Industrial I/O support --->
--- Industrial I/O support
[--snip--]
Temperature sensors --->
[--snip--]
-*- Analog Devices Multi-Sensor Digital Temperature Measurement System
[--snip--]
Hardware configuration
Driver testing
Each and every IIO device, typically a hardware chip, has a device folder under /sys/bus/iio/devices/iio:deviceX. Where X is the IIO index of the device. Under every of these directory folders reside a set of files, depending on the characteristics and features of the hardware device in question. These files are consistently generalized and documented in the IIO ABI documentation. In order to determine which IIO deviceX corresponds to which hardware device, the user can read the name file /sys/bus/iio/devices/iio:deviceX/name. In case the sequence in which the iio device drivers are loaded/registered is constant, the numbering is constant and may be known in advance.
This specifies any shell prompt running on the target
root:/> cd /sys/bus/iio/devices/ root:/sys/bus/iio/devices> ls iio:device0 root:/sys/bus/iio/devices> cd iio:device0 root:/sys/bus/iio/devices/iio:device0> ls -l -r--r--r-- 1 root root 4096 Nov 16 11:17 dev -rw-r--r-- 1 root root 4096 Nov 16 11:17 in_temp0_thermistor_raw -rw-r--r-- 1 root root 4096 Nov 16 11:17 in_temp1_rtd_raw -rw-r--r-- 1 root root 4096 Nov 16 11:17 in_temp2_diode_raw -rw-r--r-- 1 root root 4096 Nov 16 11:17 in_temp3_thermocouple_raw -rw-r--r-- 1 root root 4096 Nov 16 11:17 in_temp_scale -rw-r--r-- 1 root root 4096 Nov 16 11:17 in_voltage0_direct_adc_raw -rw-r--r-- 1 root root 4096 Nov 16 11:17 in_voltage_scale -r--r--r-- 1 root root 4096 Nov 16 11:17 name lrwxrwxrwx 1 root root 0 Nov 16 11:17 of_node -> ../../../../../../../../firmware/devicetree/base/soc/spi@7e204000/ltc2983@0 drwxr-xr-x 2 root root 0 Nov 16 11:17 power lrwxrwxrwx 1 root root 0 Nov 16 11:17 subsystem -> ../../../../../../../../bus/iio -rw-r--r-- 1 root root 4096 Nov 16 11:17 uevent root:/sys/bus/iio/devices/iio:device0>
Show device name
This specifies any shell prompt running on the target
root:/sys/bus/iio/devices/iio:device0> cat name ltc2983
Show temperature
This specifies any shell prompt running on the target
root:/sys/bus/iio/devices/iio:device0> cat in_temp0_thermistor_raw 1048576
Show temperature scale
Description:
scale to be applied to in_tempX_${sensor_type}_raw in order to obtain the measured temperature in °C or °F (depending on chip configuration).
This specifies any shell prompt running on the target
root:/sys/bus/iio/devices/iio:device0> cat in_temp_scale 0.000976562
Show voltage
This specifies any shell prompt running on the target
root:/sys/bus/iio/devices/iio:device0> cat in_voltage0_direct_adc_raw 2621440
Show Voltage scale
Description:
scale to be applied to in_voltageX_direct_adc_raw in order to obtain the measured voltage in Volts
This specifies any shell prompt running on the target
root:/sys/bus/iio/devices/iio:device0> cat in_voltage_scale 0.000000476
More Information
- IIO mailing list: linux [dash] iio [at] vger [dot] kernel [dot] org
resources/tools-software/linux-drivers/iio-temperature/ltc2983.txt · Last modified: 15 Nov 2022 14:57 by Cosmin Tanislav