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PM / devfreq: Add current freq callback in device profile

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Devfreq returns governor predicted frequency as current frequency
via sysfs interface. But device may not support all frequencies
that governor predicts. So add a callback in device profile to get
current freq from driver. Also add a new sysfs node to expose
governor predicted next target frequency.

Signed-off-by: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rajagopal Venkat 2012-10-26 01:50:26 +02:00 committed by Rafael J. Wysocki
parent 206c30cfeb
commit 7f98a905dc
3 changed files with 27 additions and 1 deletions
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11
Documentation/ABI/testing/sysfs-class-devfreq
View File

@ -19,7 +19,16 @@ 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.
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

14
drivers/devfreq/devfreq.c
View File

@ -463,6 +463,19 @@ static ssize_t show_governor(struct device *dev,
static ssize_t show_freq(struct device *dev,
struct device_attribute *attr, char *buf)
{
unsigned long freq;
struct devfreq *devfreq = to_devfreq(dev);
if (devfreq->profile->get_cur_freq &&
!devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
return sprintf(buf, "%lu\n", freq);
return sprintf(buf, "%lu\n", devfreq->previous_freq);
}
static ssize_t show_target_freq(struct device *dev,
struct device_attribute *attr, char *buf)
{
return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq);
}
@ -563,6 +576,7 @@ static ssize_t show_max_freq(struct device *dev, struct device_attribute *attr,
static struct device_attribute devfreq_attrs[] = {
__ATTR(governor, S_IRUGO, show_governor, NULL),
__ATTR(cur_freq, S_IRUGO, show_freq, NULL),
__ATTR(target_freq, S_IRUGO, show_target_freq, NULL),
__ATTR(polling_interval, S_IRUGO | S_IWUSR, show_polling_interval,
store_polling_interval),
__ATTR(min_freq, S_IRUGO | S_IWUSR, show_min_freq, store_min_freq),

3
include/linux/devfreq.h
View File

@ -66,6 +66,8 @@ struct devfreq_dev_status {
* explained above with "DEVFREQ_FLAG_*" macros.
* @get_dev_status The device should provide the current performance
* status to devfreq, which is used by governors.
* @get_cur_freq The device should provide the current frequency
* at which it is operating.
* @exit An optional callback that is called when devfreq
* is removing the devfreq object due to error or
* from devfreq_remove_device() call. If the user
@ -79,6 +81,7 @@ struct devfreq_dev_profile {
int (*target)(struct device *dev, unsigned long *freq, u32 flags);
int (*get_dev_status)(struct device *dev,
struct devfreq_dev_status *stat);
int (*get_cur_freq)(struct device *dev, unsigned long *freq);
void (*exit)(struct device *dev);
};