ads1015 1.8 KB

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