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Commit 95db3a60 authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Mauro Carvalho Chehab
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[media] v4l: Add a media_device pointer to the v4l2_device structure 



The pointer will later be used to register/unregister media entities
when registering/unregistering a v4l2_subdev or a video_device.

With the introduction of media devices, device drivers need to store a
pointer to a driver-specific structure in the device's drvdata.
v4l2_device can't claim ownership of the drvdata anymore.

To maintain compatibility with drivers that rely on v4l2_device storing
a pointer to itself in the device's drvdata, v4l2_device_register() will
keep doing so if the drvdata is NULL.

Signed-off-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: default avatarHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent e02188c9

Documentation/video4linux/v4l2-framework.txt

+12 −5
Original line number Diff line number Diff line
@@ -83,11 +83,17 @@ You must register the device instance: 


	v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);



Registration will initialize the v4l2_device struct and link dev->driver_data

to v4l2_dev. If v4l2_dev->name is empty then it will be set to a value derived

from dev (driver name followed by the bus_id, to be precise). If you set it

up before calling v4l2_device_register then it will be untouched. If dev is

NULL, then you *must* setup v4l2_dev->name before calling v4l2_device_register.

Registration will initialize the v4l2_device struct. If the dev->driver_data

field is NULL, it will be linked to v4l2_dev. Drivers that use the media

device framework in addition to the V4L2 framework need to set

dev->driver_data manually to point to the driver-specific device structure

that embed the struct v4l2_device instance. This is achieved by a

dev_set_drvdata() call before registering the V4L2 device instance.



If v4l2_dev->name is empty then it will be set to a value derived from dev

(driver name followed by the bus_id, to be precise). If you set it up before

calling v4l2_device_register then it will be untouched. If dev is NULL, then

you *must* setup v4l2_dev->name before calling v4l2_device_register.



You can use v4l2_device_set_name() to set the name based on a driver name and

a driver-global atomic_t instance. This will generate names like ivtv0, ivtv1,
@@ -108,6 +114,7 @@ You unregister with: 


	v4l2_device_unregister(struct v4l2_device *v4l2_dev);



If the dev->driver_data field points to v4l2_dev, it will be reset to NULL.

Unregistering will also automatically unregister all subdevs from the device.



If you have a hotpluggable device (e.g. a USB device), then when a disconnect

drivers/media/video/v4l2-device.c

+7 −6
Original line number Diff line number Diff line
@@ -47,8 +47,7 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev) 
	if (!v4l2_dev->name[0])

		snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",

			dev->driver->name, dev_name(dev));

	if (dev_get_drvdata(dev))

		v4l2_warn(v4l2_dev, "Non-NULL drvdata on register\n");

	if (!dev_get_drvdata(dev))

		dev_set_drvdata(dev, v4l2_dev);

	return 0;

}
@@ -72,11 +71,13 @@ EXPORT_SYMBOL_GPL(v4l2_device_set_name); 


void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)

{

	if (v4l2_dev->dev) {

	if (v4l2_dev->dev == NULL)

		return;



	if (dev_get_drvdata(v4l2_dev->dev) == v4l2_dev)

		dev_set_drvdata(v4l2_dev->dev, NULL);

	v4l2_dev->dev = NULL;

}

}

EXPORT_SYMBOL_GPL(v4l2_device_disconnect);



void v4l2_device_unregister(struct v4l2_device *v4l2_dev)

include/media/v4l2-device.h

+4 −0
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#ifndef _V4L2_DEVICE_H

#define _V4L2_DEVICE_H



#include <media/media-device.h>

#include <media/v4l2-subdev.h>



/* Each instance of a V4L2 device should create the v4l2_device struct,
@@ -39,6 +40,9 @@ struct v4l2_device { 
	   Note: dev might be NULL if there is no parent device

	   as is the case with e.g. ISA devices. */

	struct device *dev;

#if defined(CONFIG_MEDIA_CONTROLLER)

	struct media_device *mdev;

#endif

	/* used to keep track of the registered subdevs */

	struct list_head subdevs;

	/* lock this struct; can be used by the driver as well if this