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authorMyungJoo Ham <myungjoo.ham@samsung.com>2011-10-02 00:19:34 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2011-10-02 00:19:34 +0200
commitce26c5bb9569d8b826f01b8620fc16d8da6821e9 (patch)
tree3960fee73ec26f939295c92a231a09abcb4c816e /Documentation
parent9005b65099ee4f14b6be691c4574612fe947531a (diff)
PM / devfreq: Add basic governors
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>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-class-devfreq8
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
index 0ec855f479ce..23d78b5aab11 100644
--- a/Documentation/ABI/testing/sysfs-class-devfreq
+++ b/Documentation/ABI/testing/sysfs-class-devfreq
@@ -42,3 +42,11 @@ Description:
devfreq-provided central polling
(/sys/class/devfreq/.../central_polling is 0), this value
may be useless.
+
+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.