Re: [PATCH v1.3 1/5] v4l: async: Add a pointer to of_node to struct v4l2_subdev, match it

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sakari,

Thank you for the patch.

On Thursday 11 June 2015 22:18:01 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>

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

> ---
> since v1.2:
> 
> - "A" -> "The" in the of_node field comment in struct v4l2_subdev.
> 
> - A better reason for not taking a reference to the of_node is that a
>   reference is already there for struct device, pointed to by the dev field
>   of struct v4l2_subdev. The async sub-device never exists without a device.
> 
>  drivers/media/v4l2-core/v4l2-async.c | 39 ++++++++++++++++++++++-----------
>  include/media/v4l2-subdev.h          |  2 ++
>  2 files changed, 29 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-async.c
> b/drivers/media/v4l2-core/v4l2-async.c index 85a6a34..5bada20 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 +273,14 @@ int v4l2_async_register_subdev(struct v4l2_subdev *sd)
>  {
>  	struct v4l2_async_notifier *notifier;
> 
> +	/*
> +	 * No reference taken. The reference is held by the device
> +	 * (struct v4l2_subdev.dev), and async sub-device does not
> +	 * exist independently of the device at any point of time.
> +	 */
> +	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..cdd534b 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;
> +	/* The 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. */

-- 
Regards,

Laurent Pinchart