| Dirk Eibach | 8c22a8f | 2011-03-21 17:59:36 +0100 | [diff] [blame^] | 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 | |
| 22 | The inputs can be exported to 8 sysfs input files in0_input - in7_input: |
| 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 | |
| 32 | Which inputs are exported can be configured using platform data or devicetree. |
| 33 | |
| 34 | By default all inputs are exported. |
| 35 | |
| 36 | Platform Data |
| 37 | ------------- |
| 38 | |
| 39 | In linux/i2c/ads1015.h platform data is defined as: |
| 40 | |
| 41 | struct ads1015_platform_data { |
| 42 | unsigned int exported_channels; |
| 43 | }; |
| 44 | |
| 45 | exported_channels is a bitmask that specifies which inputs should be exported. |
| 46 | |
| 47 | Example: |
| 48 | struct ads1015_platform_data data = { |
| 49 | .exported_channels = (1 << 2) | (1 << 4) |
| 50 | }; |
| 51 | |
| 52 | In this case only in2_input and in4_input would be created. |
| 53 | |
| 54 | Devicetree |
| 55 | ---------- |
| 56 | |
| 57 | The ads1015 node may have an "exported-channels" property. |
| 58 | exported_channels is a bitmask that specifies which inputs should be exported. |
| 59 | |
| 60 | Example: |
| 61 | ads1015@49 { |
| 62 | compatible = "ti,ads1015"; |
| 63 | reg = <0x49>; |
| 64 | exported-channels = < 0x14 >; |
| 65 | }; |
| 66 | |
| 67 | In this case only in2_input and in4_input would be created. |