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V4L/DVB (10643): v4l2-device: allow a NULL parent device when registering.

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Some drivers (e.g. for ISA devices) have no parent device because there
is no associated bus driver. Allow the parent device to be NULL in
those cases when registering v4l2_device.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil 2009-02-14 11:54:23 -03:00 committed by Mauro Carvalho Chehab
parent 62cfdacc94
commit 3a63e4492f
3 changed files with 48 additions and 30 deletions
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10
Documentation/video4linux/v4l2-framework.txt
View file

@ -84,12 +84,14 @@ 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. Registration will also set v4l2_dev->name to a value derived from
dev (driver name followed by the bus_id, to be precise). You may change the
name after registration if you want.
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.
The first 'dev' argument is normally the struct device pointer of a pci_dev,
usb_device or platform_device.
usb_device or platform_device. It is rare for dev to be NULL, but it happens
with ISA devices, for example.
You unregister with:

37
drivers/media/video/v4l2-device.c
View file

@ -26,15 +26,24 @@
int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
{
if (dev == NULL || v4l2_dev == NULL)
if (v4l2_dev == NULL)
return -EINVAL;
/* Warn if we apparently re-register a device */
WARN_ON(dev_get_drvdata(dev) != NULL);
INIT_LIST_HEAD(&v4l2_dev->subdevs);
spin_lock_init(&v4l2_dev->lock);
v4l2_dev->dev = dev;
snprintf(v4l2_dev->name, sizeof(v4l2_dev->name), "%s %s",
if (dev == NULL) {
/* If dev == NULL, then name must be filled in by the caller */
WARN_ON(!v4l2_dev->name[0]);
return 0;
}
/* Set name to driver name + device name if it is empty. */
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");
dev_set_drvdata(dev, v4l2_dev);
return 0;
}
@ -44,10 +53,11 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
{
struct v4l2_subdev *sd, *next;
if (v4l2_dev == NULL || v4l2_dev->dev == NULL)
if (v4l2_dev == NULL)
return;
dev_set_drvdata(v4l2_dev->dev, NULL);
/* unregister subdevs */
if (v4l2_dev->dev)
dev_set_drvdata(v4l2_dev->dev, NULL);
/* Unregister subdevs */
list_for_each_entry_safe(sd, next, &v4l2_dev->subdevs, list)
v4l2_device_unregister_subdev(sd);
@ -55,19 +65,20 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev)
}
EXPORT_SYMBOL_GPL(v4l2_device_unregister);
int v4l2_device_register_subdev(struct v4l2_device *dev, struct v4l2_subdev *sd)
int v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
struct v4l2_subdev *sd)
{
/* Check for valid input */
if (dev == NULL || sd == NULL || !sd->name[0])
if (v4l2_dev == NULL || sd == NULL || !sd->name[0])
return -EINVAL;
/* Warn if we apparently re-register a subdev */
WARN_ON(sd->dev != NULL);
if (!try_module_get(sd->owner))
return -ENODEV;
sd->dev = dev;
spin_lock(&dev->lock);
list_add_tail(&sd->list, &dev->subdevs);
spin_unlock(&dev->lock);
sd->dev = v4l2_dev;
spin_lock(&v4l2_dev->lock);
list_add_tail(&sd->list, &v4l2_dev->subdevs);
spin_unlock(&v4l2_dev->lock);
return 0;
}
EXPORT_SYMBOL_GPL(v4l2_device_register_subdev);

31
include/media/v4l2-device.h
View file

@ -33,7 +33,9 @@
#define V4L2_DEVICE_NAME_SIZE (BUS_ID_SIZE + 16)
struct v4l2_device {
/* dev->driver_data points to this struct */
/* dev->driver_data points to this struct.
Note: dev might be NULL if there is no parent device
as is the case with e.g. ISA devices. */
struct device *dev;
/* used to keep track of the registered subdevs */
struct list_head subdevs;
@ -44,7 +46,9 @@ struct v4l2_device {
char name[V4L2_DEVICE_NAME_SIZE];
};
/* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev */
/* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev.
dev may be NULL in rare cases (ISA devices). In that case you
must fill in the v4l2_dev->name field before calling this function. */
int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
/* Set v4l2_dev->dev->driver_data to NULL and unregister all sub-devices */
void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
@ -52,23 +56,24 @@ void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
/* Register a subdev with a v4l2 device. While registered the subdev module
is marked as in-use. An error is returned if the module is no longer
loaded when you attempt to register it. */
int __must_check v4l2_device_register_subdev(struct v4l2_device *dev, struct v4l2_subdev *sd);
int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
struct v4l2_subdev *sd);
/* Unregister a subdev with a v4l2 device. Can also be called if the subdev
wasn't registered. In that case it will do nothing. */
void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
/* Iterate over all subdevs. */
#define v4l2_device_for_each_subdev(sd, dev) \
list_for_each_entry(sd, &(dev)->subdevs, list)
#define v4l2_device_for_each_subdev(sd, v4l2_dev) \
list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
/* Call the specified callback for all subdevs matching the condition.
Ignore any errors. Note that you cannot add or delete a subdev
while walking the subdevs list. */
#define __v4l2_device_call_subdevs(dev, cond, o, f, args...) \
#define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...) \
do { \
struct v4l2_subdev *sd; \
\
list_for_each_entry(sd, &(dev)->subdevs, list) \
list_for_each_entry(sd, &(v4l2_dev)->subdevs, list) \
if ((cond) && sd->ops->o && sd->ops->o->f) \
sd->ops->o->f(sd , ##args); \
} while (0)
@ -77,12 +82,12 @@ void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
If the callback returns an error other than 0 or -ENOIOCTLCMD, then
return with that error code. Note that you cannot add or delete a
subdev while walking the subdevs list. */
#define __v4l2_device_call_subdevs_until_err(dev, cond, o, f, args...) \
#define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
({ \
struct v4l2_subdev *sd; \
long err = 0; \
\
list_for_each_entry(sd, &(dev)->subdevs, list) { \
list_for_each_entry(sd, &(v4l2_dev)->subdevs, list) { \
if ((cond) && sd->ops->o && sd->ops->o->f) \
err = sd->ops->o->f(sd , ##args); \
if (err && err != -ENOIOCTLCMD) \
@ -94,16 +99,16 @@ void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
/* Call the specified callback for all subdevs matching grp_id (if 0, then
match them all). Ignore any errors. Note that you cannot add or delete
a subdev while walking the subdevs list. */
#define v4l2_device_call_all(dev, grpid, o, f, args...) \
__v4l2_device_call_subdevs(dev, \
#define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...) \
__v4l2_device_call_subdevs(v4l2_dev, \
!(grpid) || sd->grp_id == (grpid), o, f , ##args)
/* Call the specified callback for all subdevs matching grp_id (if 0, then
match them all). If the callback returns an error other than 0 or
-ENOIOCTLCMD, then return with that error code. Note that you cannot
add or delete a subdev while walking the subdevs list. */
#define v4l2_device_call_until_err(dev, grpid, o, f, args...) \
__v4l2_device_call_subdevs_until_err(dev, \
#define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...) \
__v4l2_device_call_subdevs_until_err(v4l2_dev, \
!(grpid) || sd->grp_id == (grpid), o, f , ##args)
#endif