PM / devfreq: Add current freq callback in device profile

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>

diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq
index 89283b1b0240f61f1454534ae12ae6106e6c0a5f..e6cf08e6734d4b727055022077afd2c7ece03d84 100644 (file)
--- 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 999600da21c7ad240af93b9031bac8e7b82f35b7..f2f8a976c465dd0a905f81261f72198e59459bec 100644 (file)
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -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),

diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index ee243a3229b8042dc79e5f56e5d459ce9a06f3b5..7e2e2ea4a70f10693c6a146497726af1e9f4265b 100644 (file)
--- 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);
 };