[linux-2.6-block.git] / 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
Commit	Line	Data
8c22a8f5 DE	1	Kernel driver ads1015
	2	=====================
	3
	4	Supported chips:
	5	* Texas Instruments ADS1015
	6	Prefix: 'ads1015'
	7	Datasheet: Publicly available at the Texas Instruments website :
	8	http://focus.ti.com/lit/ds/symlink/ads1015.pdf
	9
	10	Authors:
	11	Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>
	12
	13	Description
	14	-----------
	15
	16	This driver implements support for the Texas Instruments ADS1015.
	17
	18	This device is a 12-bit A-D converter with 4 inputs.
	19
	20	The inputs can be used single ended or in certain differential combinations.
	21
c0046867	22	The inputs can be made available by 8 sysfs input files in0_input - in7_input:
8c22a8f5 DE	23	in0: Voltage over AIN0 and AIN1.
	24	in1: Voltage over AIN0 and AIN3.
	25	in2: Voltage over AIN1 and AIN3.
	26	in3: Voltage over AIN2 and AIN3.
	27	in4: Voltage over AIN0 and GND.
	28	in5: Voltage over AIN1 and GND.
	29	in6: Voltage over AIN2 and GND.
	30	in7: Voltage over AIN3 and GND.
	31
c0046867	32	Which inputs are available can be configured using platform data or devicetree.
8c22a8f5 DE	33
	34	By default all inputs are exported.
	35
	36	Platform Data
	37	-------------
	38
c0046867 DE	39	In linux/i2c/ads1015.h platform data is defined, channel_data contains
	40	configuration data for the used input combinations:
	41	- pga is the programmable gain amplifier (values are full scale)
	42	0: +/- 6.144 V
	43	1: +/- 4.096 V
	44	2: +/- 2.048 V
	45	3: +/- 1.024 V
	46	4: +/- 0.512 V
	47	5: +/- 0.256 V
	48	- data_rate in samples per second
	49	0: 128
	50	1: 250
	51	2: 490
	52	3: 920
	53	4: 1600
	54	5: 2400
	55	6: 3300
8c22a8f5 DE	56
	57	Example:
	58	struct ads1015_platform_data data = {
c0046867 DE	59	.channel_data = {
	60	[2] = { .enabled = true, .pga = 1, .data_rate = 0 },
	61	[4] = { .enabled = true, .pga = 4, .data_rate = 5 },
	62	}
8c22a8f5 DE	63	};
8c22a8f5 DE	64
c0046867 DE	65	In this case only in2_input (FS +/- 4.096 V, 128 SPS) and in4_input
c0046867 DE	66	(FS +/- 0.512 V, 2400 SPS) would be created.
8c22a8f5 DE	67
	68	Devicetree
	69	----------
	70
c0046867 DE	71	Configuration is also possible via devicetree:
c0046867 DE	72	Documentation/devicetree/bindings/hwmon/ads1015.txt