[v1.1,1/5] v4l: async: Add a pointer to of_node to struct v4l2_subdev, match it
diff mbox

Message ID 1433111079-22457-1-git-send-email-sakari.ailus@iki.fi
State New
Headers show

Commit Message

Sakari Ailus May 31, 2015, 10:24 p.m. UTC
V4L2 async sub-devices are currently matched (OF case) based on the struct
device_node pointer in struct device. LED devices may have more than one
LED, and in that case the OF node to match is not directly the device's
node, but a LED's node.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
---
since v1:

- Move conditional setting of struct v4l2_subdev.of_node from
  v4l2_device_register_subdev() to v4l2_async_register_subdev.

- Remove the check for NULL struct v4l2_subdev.of_node from match_of() as
  it's no longer needed.

- Unconditionally state in the struct v4l2_subdev.of_node field comment that
  the field contains (a pointer to) the sub-device's of_node.

 drivers/media/v4l2-core/v4l2-async.c | 34 ++++++++++++++++++++++------------
 include/media/v4l2-subdev.h          |  2 ++
 2 files changed, 24 insertions(+), 12 deletions(-)

Comments

Laurent Pinchart June 2, 2015, 2:47 a.m. UTC | #1
Hi Sakari,

Thank you for the patch. Please see below for one small comment.

On Monday 01 June 2015 01:24:39 Sakari Ailus wrote:
> V4L2 async sub-devices are currently matched (OF case) based on the struct
> device_node pointer in struct device. LED devices may have more than one
> LED, and in that case the OF node to match is not directly the device's
> node, but a LED's node.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> ---
> since v1:
> 
> - Move conditional setting of struct v4l2_subdev.of_node from
>   v4l2_device_register_subdev() to v4l2_async_register_subdev.
> 
> - Remove the check for NULL struct v4l2_subdev.of_node from match_of() as
>   it's no longer needed.
> 
> - Unconditionally state in the struct v4l2_subdev.of_node field comment that
> the field contains (a pointer to) the sub-device's of_node.
> 
>  drivers/media/v4l2-core/v4l2-async.c | 34 +++++++++++++++++++++------------
>  include/media/v4l2-subdev.h          |  2 ++
>  2 files changed, 24 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-async.c
> b/drivers/media/v4l2-core/v4l2-async.c index 85a6a34..b0badac 100644
> --- a/drivers/media/v4l2-core/v4l2-async.c
> +++ b/drivers/media/v4l2-core/v4l2-async.c

[snip]

> @@ -266,6 +273,9 @@ int v4l2_async_register_subdev(struct v4l2_subdev *sd)
>  {
>  	struct v4l2_async_notifier *notifier;
> 
> +	if (!sd->of_node && sd->dev)
> +		sd->of_node = sd->dev->of_node;
> +

I think we don't need to take a reference to of_node here, as we assume 
there's a reference to dev through the whole life of the subdev, and dev 
should have a reference to of_node, but could you double-check ?

If that's indeed not a problem,

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

(and maybe a small comment in the source code would be useful)

>  	mutex_lock(&list_lock);
> 
>  	INIT_LIST_HEAD(&sd->async_list);
> diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
> index 8f5da73..8a17c24 100644
> --- a/include/media/v4l2-subdev.h
> +++ b/include/media/v4l2-subdev.h
> @@ -603,6 +603,8 @@ struct v4l2_subdev {
>  	struct video_device *devnode;
>  	/* pointer to the physical device, if any */
>  	struct device *dev;
> +	/* A device_node of the subdev, usually the same as dev->of_node. */
> +	struct device_node *of_node;
>  	/* Links this subdev to a global subdev_list or @notifier->done list. */
>  	struct list_head async_list;
>  	/* Pointer to respective struct v4l2_async_subdev. */
Sakari Ailus June 9, 2015, 8:05 a.m. UTC | #2
Hi Laurent,

On Tue, Jun 02, 2015 at 05:47:12AM +0300, Laurent Pinchart wrote:
> Hi Sakari,
> 
> Thank you for the patch. Please see below for one small comment.
> 
> On Monday 01 June 2015 01:24:39 Sakari Ailus wrote:
> > V4L2 async sub-devices are currently matched (OF case) based on the struct
> > device_node pointer in struct device. LED devices may have more than one
> > LED, and in that case the OF node to match is not directly the device's
> > node, but a LED's node.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
> > ---
> > since v1:
> > 
> > - Move conditional setting of struct v4l2_subdev.of_node from
> >   v4l2_device_register_subdev() to v4l2_async_register_subdev.
> > 
> > - Remove the check for NULL struct v4l2_subdev.of_node from match_of() as
> >   it's no longer needed.
> > 
> > - Unconditionally state in the struct v4l2_subdev.of_node field comment that
> > the field contains (a pointer to) the sub-device's of_node.
> > 
> >  drivers/media/v4l2-core/v4l2-async.c | 34 +++++++++++++++++++++------------
> >  include/media/v4l2-subdev.h          |  2 ++
> >  2 files changed, 24 insertions(+), 12 deletions(-)
> > 
> > diff --git a/drivers/media/v4l2-core/v4l2-async.c
> > b/drivers/media/v4l2-core/v4l2-async.c index 85a6a34..b0badac 100644
> > --- a/drivers/media/v4l2-core/v4l2-async.c
> > +++ b/drivers/media/v4l2-core/v4l2-async.c
> 
> [snip]
> 
> > @@ -266,6 +273,9 @@ int v4l2_async_register_subdev(struct v4l2_subdev *sd)
> >  {
> >  	struct v4l2_async_notifier *notifier;
> > 
> > +	if (!sd->of_node && sd->dev)
> > +		sd->of_node = sd->dev->of_node;
> > +
> 
> I think we don't need to take a reference to of_node here, as we assume 
> there's a reference to dev through the whole life of the subdev, and dev 
> should have a reference to of_node, but could you double-check ?
> 
> If that's indeed not a problem,
> 
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Good question.

I don't think a reference would be needed also because we are only
interested in the pointer value itself, the memory the pointer is pointing
to is never accessed.

As far as I can tell, there's no reference through the device.

I can add a comment on this if you like. Perhaps it'd be a good idea
actually, as you usually do take a reference in such cases.

Patch
diff mbox

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 85a6a34..b0badac 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -22,10 +22,10 @@ 
 #include <media/v4l2-device.h>
 #include <media/v4l2-subdev.h>
 
-static bool match_i2c(struct device *dev, struct v4l2_async_subdev *asd)
+static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
 {
 #if IS_ENABLED(CONFIG_I2C)
-	struct i2c_client *client = i2c_verify_client(dev);
+	struct i2c_client *client = i2c_verify_client(sd->dev);
 	return client &&
 		asd->match.i2c.adapter_id == client->adapter->nr &&
 		asd->match.i2c.address == client->addr;
@@ -34,14 +34,24 @@  static bool match_i2c(struct device *dev, struct v4l2_async_subdev *asd)
 #endif
 }
 
-static bool match_devname(struct device *dev, struct v4l2_async_subdev *asd)
+static bool match_devname(struct v4l2_subdev *sd,
+			  struct v4l2_async_subdev *asd)
 {
-	return !strcmp(asd->match.device_name.name, dev_name(dev));
+	return !strcmp(asd->match.device_name.name, dev_name(sd->dev));
 }
 
-static bool match_of(struct device *dev, struct v4l2_async_subdev *asd)
+static bool match_of(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
 {
-	return dev->of_node == asd->match.of.node;
+	return sd->of_node == asd->match.of.node;
+}
+
+static bool match_custom(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
+{
+	if (!asd->match.custom.match)
+		/* Match always */
+		return true;
+
+	return asd->match.custom.match(sd->dev, asd);
 }
 
 static LIST_HEAD(subdev_list);
@@ -51,17 +61,14 @@  static DEFINE_MUTEX(list_lock);
 static struct v4l2_async_subdev *v4l2_async_belongs(struct v4l2_async_notifier *notifier,
 						    struct v4l2_subdev *sd)
 {
+	bool (*match)(struct v4l2_subdev *, struct v4l2_async_subdev *);
 	struct v4l2_async_subdev *asd;
-	bool (*match)(struct device *, struct v4l2_async_subdev *);
 
 	list_for_each_entry(asd, &notifier->waiting, list) {
 		/* bus_type has been verified valid before */
 		switch (asd->match_type) {
 		case V4L2_ASYNC_MATCH_CUSTOM:
-			match = asd->match.custom.match;
-			if (!match)
-				/* Match always */
-				return asd;
+			match = match_custom;
 			break;
 		case V4L2_ASYNC_MATCH_DEVNAME:
 			match = match_devname;
@@ -79,7 +86,7 @@  static struct v4l2_async_subdev *v4l2_async_belongs(struct v4l2_async_notifier *
 		}
 
 		/* match cannot be NULL here */
-		if (match(sd->dev, asd))
+		if (match(sd, asd))
 			return asd;
 	}
 
@@ -266,6 +273,9 @@  int v4l2_async_register_subdev(struct v4l2_subdev *sd)
 {
 	struct v4l2_async_notifier *notifier;
 
+	if (!sd->of_node && sd->dev)
+		sd->of_node = sd->dev->of_node;
+
 	mutex_lock(&list_lock);
 
 	INIT_LIST_HEAD(&sd->async_list);
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index 8f5da73..8a17c24 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -603,6 +603,8 @@  struct v4l2_subdev {
 	struct video_device *devnode;
 	/* pointer to the physical device, if any */
 	struct device *dev;
+	/* A device_node of the subdev, usually the same as dev->of_node. */
+	struct device_node *of_node;
 	/* Links this subdev to a global subdev_list or @notifier->done list. */
 	struct list_head async_list;
 	/* Pointer to respective struct v4l2_async_subdev. */