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Four cpufreq-like governors are provided as examples. powersave: use the lowest frequency possible. The user (device) should set the polling_ms as 0 because polling is useless for this governor. performance: use the highest freqeuncy possible. The user (device) should set the polling_ms as 0 because polling is useless for this governor. userspace: use the user specified frequency stored at devfreq.user_set_freq. With sysfs support in the following patch, a user may set the value with the sysfs interface. simple_ondemand: simplified version of cpufreq's ondemand governor. When a user updates OPP entries (enable/disable/add), OPP framework automatically notifies devfreq to update operating frequency accordingly. Thus, devfreq users (device drivers) do not need to update devfreq manually with OPP entry updates or set polling_ms for powersave , performance, userspace, or any other "static" governors. Note that these are given only as basic examples for governors and any devices with devfreq may implement their own governors with the drivers and use them. Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Reviewed-by: Mike Turquette <mturquette@ti.com> Acked-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
52 lines
1.9 KiB
Text
52 lines
1.9 KiB
Text
What: /sys/class/devfreq/.../
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Date: September 2011
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Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
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Description:
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Provide a place in sysfs for the devfreq objects.
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This allows accessing various devfreq specific variables.
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The name of devfreq object denoted as ... is same as the
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name of device using devfreq.
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What: /sys/class/devfreq/.../governor
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Date: September 2011
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Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
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Description:
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The /sys/class/devfreq/.../governor shows the name of the
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governor used by the corresponding devfreq object.
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What: /sys/class/devfreq/.../cur_freq
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Date: September 2011
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Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
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Description:
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The /sys/class/devfreq/.../cur_freq shows the current
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frequency of the corresponding devfreq object.
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What: /sys/class/devfreq/.../central_polling
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Date: September 2011
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Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
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Description:
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The /sys/class/devfreq/.../central_polling shows whether
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the devfreq ojbect is using devfreq-provided central
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polling mechanism or not.
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What: /sys/class/devfreq/.../polling_interval
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Date: September 2011
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Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
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Description:
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The /sys/class/devfreq/.../polling_interval shows and sets
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the requested polling interval of the corresponding devfreq
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object. The values are represented in ms. If the value is
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less than 1 jiffy, it is considered to be 0, which means
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no polling. This value is meaningless if the governor is
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not polling; thus. If the governor is not using
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devfreq-provided central polling
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(/sys/class/devfreq/.../central_polling is 0), this value
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may be useless.
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What: /sys/class/devfreq/.../userspace/set_freq
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Date: September 2011
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Contact: MyungJoo Ham <myungjoo.ham@samsung.com>
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Description:
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The /sys/class/devfreq/.../userspace/set_freq shows and
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sets the requested frequency for the devfreq object if
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userspace governor is in effect.
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