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

Rajagopal Venkat
2012-09-13T13:58:59Z

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>
---
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