You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
76 lines
2.0 KiB
76 lines
2.0 KiB
Kernel driver ads1015 |
|
===================== |
|
|
|
Supported chips: |
|
* Texas Instruments ADS1015 |
|
Prefix: 'ads1015' |
|
Datasheet: Publicly available at the Texas Instruments website : |
|
http://focus.ti.com/lit/ds/symlink/ads1015.pdf |
|
* Texas Instruments ADS1115 |
|
Prefix: 'ads1115' |
|
Datasheet: Publicly available at the Texas Instruments website : |
|
http://focus.ti.com/lit/ds/symlink/ads1115.pdf |
|
|
|
Authors: |
|
Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de> |
|
|
|
Description |
|
----------- |
|
|
|
This driver implements support for the Texas Instruments ADS1015/ADS1115. |
|
|
|
This device is a 12/16-bit A-D converter with 4 inputs. |
|
|
|
The inputs can be used single ended or in certain differential combinations. |
|
|
|
The inputs can be made available by 8 sysfs input files in0_input - in7_input: |
|
in0: Voltage over AIN0 and AIN1. |
|
in1: Voltage over AIN0 and AIN3. |
|
in2: Voltage over AIN1 and AIN3. |
|
in3: Voltage over AIN2 and AIN3. |
|
in4: Voltage over AIN0 and GND. |
|
in5: Voltage over AIN1 and GND. |
|
in6: Voltage over AIN2 and GND. |
|
in7: Voltage over AIN3 and GND. |
|
|
|
Which inputs are available can be configured using platform data or devicetree. |
|
|
|
By default all inputs are exported. |
|
|
|
Platform Data |
|
------------- |
|
|
|
In linux/i2c/ads1015.h platform data is defined, channel_data contains |
|
configuration data for the used input combinations: |
|
- pga is the programmable gain amplifier (values are full scale) |
|
0: +/- 6.144 V |
|
1: +/- 4.096 V |
|
2: +/- 2.048 V |
|
3: +/- 1.024 V |
|
4: +/- 0.512 V |
|
5: +/- 0.256 V |
|
- data_rate in samples per second |
|
0: 128 |
|
1: 250 |
|
2: 490 |
|
3: 920 |
|
4: 1600 |
|
5: 2400 |
|
6: 3300 |
|
|
|
Example: |
|
struct ads1015_platform_data data = { |
|
.channel_data = { |
|
[2] = { .enabled = true, .pga = 1, .data_rate = 0 }, |
|
[4] = { .enabled = true, .pga = 4, .data_rate = 5 }, |
|
} |
|
}; |
|
|
|
In this case only in2_input (FS +/- 4.096 V, 128 SPS) and in4_input |
|
(FS +/- 0.512 V, 2400 SPS) would be created. |
|
|
|
Devicetree |
|
---------- |
|
|
|
Configuration is also possible via devicetree: |
|
Documentation/devicetree/bindings/hwmon/ads1015.txt
|
|
|