[PATCH] power:sysfs: Expose device wakeup_event_count.

[Ravi Chandra Sadineni]

Device level event_count can help user level daemon to track if a
praticular device has seen an wake interrupt during a suspend resume
cycle. Thus expose it via sysfs.

Signed-off-by: Ravi Chandra Sadineni <ravisadineni@xxxxxxxxxxxx>
---
 Documentation/ABI/testing/sysfs-devices-power | 11 ++++++++++
 drivers/base/power/sysfs.c                    | 20 +++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-devices-power b/Documentation/ABI/testing/sysfs-devices-power
index 1ca04b4f0489..344549f4013f 100644
--- a/Documentation/ABI/testing/sysfs-devices-power
+++ b/Documentation/ABI/testing/sysfs-devices-power
@@ -89,6 +89,17 @@ Description:
 		attribute is not present. If the device is not enabled to wake
 		up the system from sleep states, this attribute is empty.
 
+What:		/sys/devices/.../power/wakeup_event_count
+Date:		July 2019
+Contact:	Ravi Chandra sadineni <ravisadineni@xxxxxxxxxxxx>
+Description:
+		The /sys/devices/.../wakeup_event_count attribute contains the
+		number of signaled wakeup events associated with the device.
+		This attribute is read-only. If the device is not capable to
+		wake up the system from sleep states, this attribute is not
+		present. If the device is not enabled to wake up the system
+		from sleep states, this attribute is empty.
+
 What:		/sys/devices/.../power/wakeup_active_count
 Date:		September 2010
 Contact:	Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index f42044d9711c..8dc1235b9784 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -357,6 +357,25 @@ static ssize_t wakeup_count_show(struct device *dev,
 
 static DEVICE_ATTR_RO(wakeup_count);
 
+static ssize_t wakeup_event_count_show(struct device *dev,
+				 struct device_attribute *attr, char *buf)
+{
+	unsigned long count = 0;
+	bool enabled = false;
+
+	spin_lock_irq(&dev->power.lock);
+	if (dev->power.wakeup) {
+		count = dev->power.wakeup->event_count;
+		enabled = true;
+	}
+	spin_unlock_irq(&dev->power.lock);
+	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
+}
+
+static DEVICE_ATTR_RO(wakeup_event_count);
+
+
+
 static ssize_t wakeup_active_count_show(struct device *dev,
 					struct device_attribute *attr,
 					char *buf)
@@ -561,6 +580,7 @@ static struct attribute *wakeup_attrs[] = {
 #ifdef CONFIG_PM_SLEEP
 	&dev_attr_wakeup.attr,
 	&dev_attr_wakeup_count.attr,
+	&dev_attr_wakeup_event_count.attr,
 	&dev_attr_wakeup_active_count.attr,
 	&dev_attr_wakeup_expire_count.attr,
 	&dev_attr_wakeup_active.attr,
-- 
2.20.1