linux-pinenote/Documentation/hwmon/ads1015

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

Authors:
        Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>

Description
-----------

This driver implements support for the Texas Instruments ADS1015.

This device is a 12-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