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Diffstat (limited to 'Documentation/ABI/testing/sysfs-class-devfreq')
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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 |