sysfs-class-devfreq 4.5 KB

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  1. What: /sys/class/devfreq/.../
  2. Date: September 2011
  3. Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
  4. Description:
  5. Provide a place in sysfs for the devfreq objects.
  6. This allows accessing various devfreq specific variables.
  7. The name of devfreq object denoted as ... is same as the
  8. name of device using devfreq.
  9. What: /sys/class/devfreq/.../name
  10. Date: November 2019
  11. Contact: Chanwoo Choi <cw00.choi@samsung.com>
  12. Description:
  13. The /sys/class/devfreq/.../name shows the name of device
  14. of the corresponding devfreq object.
  15. What: /sys/class/devfreq/.../governor
  16. Date: September 2011
  17. Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
  18. Description:
  19. The /sys/class/devfreq/.../governor show or set the name of the
  20. governor used by the corresponding devfreq object.
  21. What: /sys/class/devfreq/.../cur_freq
  22. Date: September 2011
  23. Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
  24. Description:
  25. The /sys/class/devfreq/.../cur_freq shows the current
  26. frequency of the corresponding devfreq object. Same as
  27. target_freq when get_cur_freq() is not implemented by
  28. devfreq driver.
  29. What: /sys/class/devfreq/.../target_freq
  30. Date: September 2012
  31. Contact: Rajagopal Venkat <rajagopal.venkat@linaro.org>
  32. Description:
  33. The /sys/class/devfreq/.../target_freq shows the next governor
  34. predicted target frequency of the corresponding devfreq object.
  35. What: /sys/class/devfreq/.../polling_interval
  36. Date: September 2011
  37. Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
  38. Description:
  39. The /sys/class/devfreq/.../polling_interval shows and sets
  40. the requested polling interval of the corresponding devfreq
  41. object. The values are represented in ms. If the value is
  42. less than 1 jiffy, it is considered to be 0, which means
  43. no polling. This value is meaningless if the governor is
  44. not polling; thus. If the governor is not using
  45. devfreq-provided central polling
  46. (/sys/class/devfreq/.../central_polling is 0), this value
  47. may be useless.
  48. What: /sys/class/devfreq/.../trans_stat
  49. Date: October 2012
  50. Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
  51. Description:
  52. This ABI shows or clears the statistics of devfreq behavior
  53. on a specific device. It shows the time spent in each state
  54. and the number of transitions between states.
  55. In order to activate this ABI, the devfreq target device
  56. driver should provide the list of available frequencies
  57. with its profile. If need to reset the statistics of devfreq
  58. behavior on a specific device, enter 0(zero) to 'trans_stat'
  59. as following::
  60. echo 0 > /sys/class/devfreq/.../trans_stat
  61. What: /sys/class/devfreq/.../userspace/set_freq
  62. Date: September 2011
  63. Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
  64. Description:
  65. The /sys/class/devfreq/.../userspace/set_freq shows and
  66. sets the requested frequency for the devfreq object if
  67. userspace governor is in effect.
  68. What: /sys/class/devfreq/.../available_frequencies
  69. Date: October 2012
  70. Contact: Nishanth Menon <nm@ti.com>
  71. Description:
  72. The /sys/class/devfreq/.../available_frequencies shows
  73. the available frequencies of the corresponding devfreq object.
  74. This is a snapshot of available frequencies and not limited
  75. by the min/max frequency restrictions.
  76. What: /sys/class/devfreq/.../available_governors
  77. Date: October 2012
  78. Contact: Nishanth Menon <nm@ti.com>
  79. Description:
  80. The /sys/class/devfreq/.../available_governors shows
  81. currently available governors in the system.
  82. What: /sys/class/devfreq/.../min_freq
  83. Date: January 2013
  84. Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
  85. Description:
  86. The /sys/class/devfreq/.../min_freq shows and stores
  87. the minimum frequency requested by users. It is 0 if
  88. the user does not care. min_freq overrides the
  89. frequency requested by governors.
  90. What: /sys/class/devfreq/.../max_freq
  91. Date: January 2013
  92. Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
  93. Description:
  94. The /sys/class/devfreq/.../max_freq shows and stores
  95. the maximum frequency requested by users. It is 0 if
  96. the user does not care. max_freq overrides the
  97. frequency requested by governors and min_freq.
  98. The max_freq overrides min_freq because max_freq may be
  99. used to throttle devices to avoid overheating.
  100. What: /sys/class/devfreq/.../timer
  101. Date: July 2020
  102. Contact: Chanwoo Choi <cw00.choi@samsung.com>
  103. Description:
  104. This ABI shows and stores the kind of work timer by users.
  105. This work timer is used by devfreq workqueue in order to
  106. monitor the device status such as utilization. The user
  107. can change the work timer on runtime according to their demand
  108. as following::
  109. echo deferrable > /sys/class/devfreq/.../timer
  110. echo delayed > /sys/class/devfreq/.../timer