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/.../trans_stat
  41 Date:           October 2012
  42 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  43 Description:
  44                 This ABI shows or clears the statistics of devfreq behavior
  45                 on a specific device. It shows the time spent in each state
  46                 and the number of transitions between states.
  47                 In order to activate this ABI, the devfreq target device
  48                 driver should provide the list of available frequencies
  49                 with its profile. If need to reset the statistics of devfreq
  50                 behavior on a specific device, enter 0(zero) to 'trans_stat'
  51                 as following::
  52
  53                         echo 0 > /sys/class/devfreq/.../trans_stat
  54
  55 What:           /sys/class/devfreq/.../available_frequencies
  56 Date:           October 2012
  57 Contact:        Nishanth Menon <nm@ti.com>
  58 Description:
  59                 The /sys/class/devfreq/.../available_frequencies shows
  60                 the available frequencies of the corresponding devfreq object.
  61                 This is a snapshot of available frequencies and not limited
  62                 by the min/max frequency restrictions.
  63
  64 What:           /sys/class/devfreq/.../available_governors
  65 Date:           October 2012
  66 Contact:        Nishanth Menon <nm@ti.com>
  67 Description:
  68                 The /sys/class/devfreq/.../available_governors shows
  69                 currently available governors in the system.
  70
  71 What:           /sys/class/devfreq/.../min_freq
  72 Date:           January 2013
  73 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  74 Description:
  75                 The /sys/class/devfreq/.../min_freq shows and stores
  76                 the minimum frequency requested by users. It is 0 if
  77                 the user does not care. min_freq overrides the
  78                 frequency requested by governors.
  79
  80 What:           /sys/class/devfreq/.../max_freq
  81 Date:           January 2013
  82 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  83 Description:
  84                 The /sys/class/devfreq/.../max_freq shows and stores
  85                 the maximum frequency requested by users. It is 0 if
  86                 the user does not care. max_freq overrides the
  87                 frequency requested by governors and min_freq.
  88                 The max_freq overrides min_freq because max_freq may be
  89                 used to throttle devices to avoid overheating.
  90
  91 What:           /sys/class/devfreq/.../polling_interval
  92 Date:           September 2011
  93 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
  94 Description:
  95                 The /sys/class/devfreq/.../polling_interval shows and sets
  96                 the requested polling interval of the corresponding devfreq
  97                 object. The values are represented in ms. If the value is
  98                 less than 1 jiffy, it is considered to be 0, which means
  99                 no polling. This value is meaningless if the governor is
 100                 not polling; thus. If the governor is not using
 101                 devfreq-provided central polling
 102                 (/sys/class/devfreq/.../central_polling is 0), this value
 103                 may be useless.
 104
 105                 A list of governors that support the node:
 106                 - simple_ondmenad
 107                 - tegra_actmon
 108
 109 What:           /sys/class/devfreq/.../userspace/set_freq
 110 Date:           September 2011
 111 Contact:        MyungJoo Ham <myungjoo.ham@samsung.com>
 112 Description:
 113                 The /sys/class/devfreq/.../userspace/set_freq shows and
 114                 sets the requested frequency for the devfreq object if
 115                 userspace governor is in effect.
 116
 117                 A list of governors that support the node:
 118                 - userspace
 119
 120 What:           /sys/class/devfreq/.../timer
 121 Date:           July 2020
 122 Contact:        Chanwoo Choi <cw00.choi@samsung.com>
 123 Description:
 124                 This ABI shows and stores the kind of work timer by users.
 125                 This work timer is used by devfreq workqueue in order to
 126                 monitor the device status such as utilization. The user
 127                 can change the work timer on runtime according to their demand
 128                 as following::
 129
 130                         echo deferrable > /sys/class/devfreq/.../timer
 131                         echo delayed > /sys/class/devfreq/.../timer
 132
 133                 A list of governors that support the node:
 134                 - simple_ondemand