linux/Documentation/hwmon/ads1015.rst

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/platform_data/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