summaryrefslogtreecommitdiffstats
path: root/Documentation/ABI/testing/sysfs-class-devfreq
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/ABI/testing/sysfs-class-devfreq')
-rw-r--r--Documentation/ABI/testing/sysfs-class-devfreq134
1 files changed, 134 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
new file mode 100644
index 0000000000..1e7e0bb4c1
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-devfreq
@@ -0,0 +1,134 @@
+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/.../name
+Date: November 2019
+Contact: Chanwoo Choi <cw00.choi@samsung.com>
+Description:
+ The /sys/class/devfreq/.../name shows the name of device
+ of the corresponding devfreq object.
+
+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/.../trans_stat
+Date: October 2012
+Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
+Description:
+ This ABI shows or clears 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. If need to reset the statistics of devfreq
+ behavior on a specific device, enter 0(zero) to 'trans_stat'
+ as following::
+
+ echo 0 > /sys/class/devfreq/.../trans_stat
+
+ If the transition table is bigger than PAGE_SIZE, reading
+ this will return an -EFBIG error.
+
+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.
+
+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.
+
+ A list of governors that support the node:
+ - simple_ondmenad
+ - tegra_actmon
+
+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.
+
+ A list of governors that support the node:
+ - userspace
+
+What: /sys/class/devfreq/.../timer
+Date: July 2020
+Contact: Chanwoo Choi <cw00.choi@samsung.com>
+Description:
+ This ABI shows and stores the kind of work timer by users.
+ This work timer is used by devfreq workqueue in order to
+ monitor the device status such as utilization. The user
+ can change the work timer on runtime according to their demand
+ as following::
+
+ echo deferrable > /sys/class/devfreq/.../timer
+ echo delayed > /sys/class/devfreq/.../timer
+
+ A list of governors that support the node:
+ - simple_ondemand