[PATCH] power:sysfs: Expose device wakeup_event_count.

[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@chromium.org>
---
 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@chromium.org>
+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@rjwysocki.net>
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

Re: [PATCH] power:sysfs: Expose device wakeup_event_count.

[Greg KH]

On Mon, Jul 22, 2019 at 11:02:58AM -0700, Ravi Chandra Sadineni wrote:
> 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@chromium.org>
> ---
>  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@chromium.org>
> +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.

The attribute is not "empty" it returns just an empty line.

Is that really a good thing if you are expecting a number?

> +
>  What:		/sys/devices/.../power/wakeup_active_count
>  Date:		September 2010
>  Contact:	Rafael J. Wysocki <rjw@rjwysocki.net>
> 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);

Why do you need to lock?  The state and count can change right after the
lock, so what does this help with?

> +	return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");

Use a real if statement please.

> +}
> +
> +static DEVICE_ATTR_RO(wakeup_event_count);
> +
> +
> +

too many empty lines :)

thanks,

greg k-h

Re: [PATCH] power:sysfs: Expose device wakeup_event_count.

[Ravi Chandra Sadineni]

Hi Greg,

On Mon, Jul 22, 2019 at 11:22 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Mon, Jul 22, 2019 at 11:02:58AM -0700, Ravi Chandra Sadineni wrote:
> > 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@chromium.org>
> > ---
> >  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@chromium.org>
> > +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.
>
> The attribute is not "empty" it returns just an empty line.
Corrected the description.
>
> Is that really a good thing if you are expecting a number?
This is to adhere to the convention as described in
base/power/sysfs.c. Hope this is o.k
>
> > +
> >  What:                /sys/devices/.../power/wakeup_active_count
> >  Date:                September 2010
> >  Contact:     Rafael J. Wysocki <rjw@rjwysocki.net>
> > 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);
>
> Why do you need to lock?  The state and count can change right after the
> lock, so what does this help with?
power.wakeup can be NULL (device_wakeup_detach ()) if wakeup is
disabled for a particular device.
>
> > +     return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
>
> Use a real if statement please.
>
> > +}
> > +
> > +static DEVICE_ATTR_RO(wakeup_event_count);
> > +
> > +
> > +
>
> too many empty lines :)
Removed the empty lines.
>
> thanks,
>
> greg k-h

Thanks,
Ravi