projects / deliverable / linux.git / blame
| 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 | ||
| 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. |