Re: [PATCH v2 3/3] devfreq: Add current freq callback in device profile

From: Rajagopal Venkat rajagopal.venkat@linaro.org

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

Signed-off-by: MyungJoo Ham myungjoo.ham@samsung.com

---

Documentation/ABI/testing/sysfs-class-devfreq | 11 ++++++++++- drivers/devfreq/devfreq.c | 14 ++++++++++++++ include/linux/devfreq.h | 3 +++ 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq index 89283b1..e6cf08e 100644 --- a/Documentation/ABI/testing/sysfs-class-devfreq +++ b/Documentation/ABI/testing/sysfs-class-devfreq @@ -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 diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 309c46e..049e273 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -401,6 +401,19 @@ 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); } @@ -504,6 +517,7 @@ 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),

diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h index 7c7e179..d12ed41 100644 --- a/include/linux/devfreq.h +++ b/include/linux/devfreq.h @@ -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);

}; -- 1.7.11.3