sysfs-class-backlight 2.3 KB

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  1. What: /sys/class/backlight/<backlight>/scale
  2. Date: July 2019
  3. KernelVersion: 5.4
  4. Contact: Daniel Thompson <daniel.thompson@linaro.org>
  5. Description:
  6. Description of the scale of the brightness curve.
  7. The human eye senses brightness approximately logarithmically,
  8. hence linear changes in brightness are perceived as being
  9. non-linear. To achieve a linear perception of brightness changes
  10. controls like sliders need to apply a logarithmic mapping for
  11. backlights with a linear brightness curve.
  12. Possible values of the attribute are:
  13. unknown
  14. The scale of the brightness curve is unknown.
  15. linear
  16. The brightness changes linearly with each step. Brightness
  17. controls should apply a logarithmic mapping for a linear
  18. perception.
  19. non-linear
  20. The brightness changes non-linearly with each step. Brightness
  21. controls should use a linear mapping for a linear perception.
  22. What: /sys/class/backlight/<backlight>/ambient_light_level
  23. Date: Apr, 2010
  24. KernelVersion: v2.6.35
  25. Contact: Michael Hennerich <michael.hennerich@analog.com>
  26. Description:
  27. (RO) Get conversion value of the light sensor.
  28. The value is automatically updated every 80 ms when the
  29. light sensor is enabled.
  30. The value range is device-driver specific:
  31. For ADP8870:
  32. It returns integer between 0 (dark) and 8000 (max ambient
  33. brightness).
  34. For ADP8860:
  35. It returns a 13-bits integer.
  36. What: /sys/class/backlight/<backlight>/ambient_light_zone
  37. Date: Apr, 2010
  38. KernelVersion: v2.6.35
  39. Contact: Michael Hennerich <michael.hennerich@analog.com>,
  40. device-drivers-devel@blackfin.uclinux.org
  41. Description:
  42. (RW) Read or write the specific brightness level at which the
  43. backlight operates.
  44. The value meaning is device-driver specific:
  45. For ADP8860:
  46. == ==========================
  47. 0 Off: Backlight set to 0 mA
  48. 1 Level 1: daylight
  49. 2 Level 2: bright
  50. 3 Level 3: dark
  51. == ==========================
  52. For ADP8870:
  53. == ==========================
  54. 0 Off: Backlight set to 0 mA
  55. 1 Level 1: daylight
  56. 2 Level 2: bright
  57. 3 Level 3: office
  58. 4 Level 4: indoor
  59. 5 Level 5: dark
  60. == ==========================
  61. Writing 0 returns to normal/automatic ambient light level
  62. operation.
  63. It can be enabled by writing the value stored in
  64. /sys/class/backlight/<backlight>/max_brightness to
  65. /sys/class/backlight/<backlight>/brightness.