v4.19.13 snapshot.
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+What: /sys/class/devfreq/.../
+Date: September 2011
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ Provide a place in sysfs for the devfreq objects.
+ This allows accessing various devfreq specific variables.
+ The name of devfreq object denoted as ... is same as the
+ name of device using devfreq.
+
+What: /sys/class/devfreq/.../governor
+Date: September 2011
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ The /sys/class/devfreq/.../governor show or set the name of the
+ governor used by the corresponding devfreq object.
+
+What: /sys/class/devfreq/.../cur_freq
+Date: September 2011
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ The /sys/class/devfreq/.../cur_freq shows the current
+ frequency of the corresponding devfreq object. Same as
+ target_freq when get_cur_freq() is not implemented by
+ devfreq driver.
+
+What: /sys/class/devfreq/.../target_freq
+Date: September 2012
+Contact: Rajagopal Venkat <rajagopal.venkat@linaro.org>
+Description:
+ The /sys/class/devfreq/.../target_freq shows the next governor
+ predicted target frequency of the corresponding devfreq object.
+
+What: /sys/class/devfreq/.../polling_interval
+Date: September 2011
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ The /sys/class/devfreq/.../polling_interval shows and sets
+ the requested polling interval of the corresponding devfreq
+ object. The values are represented in ms. If the value is
+ less than 1 jiffy, it is considered to be 0, which means
+ no polling. This value is meaningless if the governor is
+ not polling; thus. If the governor is not using
+ devfreq-provided central polling
+ (/sys/class/devfreq/.../central_polling is 0), this value
+ may be useless.
+
+What: /sys/class/devfreq/.../trans_stat
+Date: October 2012
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Descrtiption:
+ This ABI shows the statistics of devfreq behavior on a
+ specific device. It shows the time spent in each state and
+ the number of transitions between states.
+ In order to activate this ABI, the devfreq target device
+ driver should provide the list of available frequencies
+ with its profile.
+
+What: /sys/class/devfreq/.../userspace/set_freq
+Date: September 2011
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ The /sys/class/devfreq/.../userspace/set_freq shows and
+ sets the requested frequency for the devfreq object if
+ userspace governor is in effect.
+
+What: /sys/class/devfreq/.../available_frequencies
+Date: October 2012
+Contact: Nishanth Menon <nm@ti.com>
+Description:
+ The /sys/class/devfreq/.../available_frequencies shows
+ the available frequencies of the corresponding devfreq object.
+ This is a snapshot of available frequencies and not limited
+ by the min/max frequency restrictions.
+
+What: /sys/class/devfreq/.../available_governors
+Date: October 2012
+Contact: Nishanth Menon <nm@ti.com>
+Description:
+ The /sys/class/devfreq/.../available_governors shows
+ currently available governors in the system.
+
+What: /sys/class/devfreq/.../min_freq
+Date: January 2013
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ The /sys/class/devfreq/.../min_freq shows and stores
+ the minimum frequency requested by users. It is 0 if
+ the user does not care. min_freq overrides the
+ frequency requested by governors.
+
+What: /sys/class/devfreq/.../max_freq
+Date: January 2013
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ The /sys/class/devfreq/.../max_freq shows and stores
+ the maximum frequency requested by users. It is 0 if
+ the user does not care. max_freq overrides the
+ frequency requested by governors and min_freq.
+ The max_freq overrides min_freq because max_freq may be
+ used to throttle devices to avoid overheating.