PM / devfreq: Simplify the sysfs name of devfreq-event device

This patch just removes '.' character from the sysfs name of devfreq-event
device as following. Usually, the subsystem uses the similiar naming style
such as {framework name}{Number}.
- old : /sys/class/devfreq-event/event.(X)
- new : /sys/class/devfreq-event/event(X)

And this patch initializes the value of 'event_no' with -1
in order to remove the unneeded operation (-1) when calling
the atomic_inc_return(&event_no).

Lastly, this patch adds the ABI document for devfreq-event class.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

2 files changed, 27 insertions, 2 deletions

diff --git a/Documentation/ABI/testing/sysfs-class-devfreq-event b/Documentation/ABI/testing/sysfs-class-devfreq-event
new file mode 100644
index 000000000000..ceaf0f686d4a
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-devfreq-event
@@ -0,0 +1,25 @@
+What:           /sys/class/devfreq-event/event(x)/
+Date:           January 2017
+Contact:        Chanwoo Choi <cw00.choi@samsung.com>
+Description:
+                Provide a place in sysfs for the devfreq-event objects.
+                This allows accessing various devfreq-event specific variables.
+                The name of devfreq-event object denoted as 'event(x)' which
+                includes the unique number of 'x' for each devfreq-event object.
+
+What:           /sys/class/devfreq-event/event(x)/name
+Date:           January 2017
+Contact:        Chanwoo Choi <cw00.choi@samsung.com>
+Description:
+                The /sys/class/devfreq-event/event(x)/name attribute contains
+                the name of the devfreq-event object. This attribute is
+                read-only.
+
+What:           /sys/class/devfreq-event/event(x)/enable_count
+Date:           January 2017
+Contact:        Chanwoo Choi <cw00.choi@samsung.com>
+Description:
+                The /sys/class/devfreq-event/event(x)/enable_count attribute
+                contains the reference count to enable the devfreq-event
+                object. If the device is enabled, the value of attribute is
+                greater than zero.
diff --git a/drivers/devfreq/devfreq-event.c b/drivers/devfreq/devfreq-event.c
index 9aea2c7ecbe6..8648b32ebc89 100644
--- a/drivers/devfreq/devfreq-event.c
+++ b/drivers/devfreq/devfreq-event.c
@@ -306,7 +306,7 @@ struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
                                                 struct devfreq_event_desc *desc)
 {
         struct devfreq_event_dev *edev;
-        static atomic_t event_no = ATOMIC_INIT(0);
+        static atomic_t event_no = ATOMIC_INIT(-1);
         int ret;
 
         if (!dev || !desc)
@@ -329,7 +329,7 @@ struct devfreq_event_dev *devfreq_event_add_edev(struct device *dev,
         edev->dev.class = devfreq_event_class;
         edev->dev.release = devfreq_event_release_edev;
 
-        dev_set_name(&edev->dev, "event.%d", atomic_inc_return(&event_no) - 1);
+        dev_set_name(&edev->dev, "event%d", atomic_inc_return(&event_no));
         ret = device_register(&edev->dev);
         if (ret < 0) {
                 put_device(&edev->dev);