Documentation/ABI/testing/sysfs-class-devfreq

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