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V4L/DVB (11671): v4l2: add v4l2_device_set_name()

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Add a utility function that can be used to setup the v4l2_device's name
field in a standard manner.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Hans Verkuil 2009-05-02 10:12:50 -03:00 committed by Mauro Carvalho Chehab
parent 416a7aa883
commit 102e781364
3 changed files with 42 additions and 0 deletions
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5
Documentation/video4linux/v4l2-framework.txt
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@ -89,6 +89,11 @@ 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 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. 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,
etc. If the name ends with a digit, then it will insert a dash: cx18-0,
cx18-1, etc. This function returns the instance number.
The first 'dev' argument is normally the struct device pointer of a pci_dev, The first 'dev' argument is normally the struct device pointer of a pci_dev,
usb_interface or platform_device. It is rare for dev to be NULL, but it happens usb_interface or platform_device. It is rare for dev to be NULL, but it happens
with ISA devices or when one device creates multiple PCI devices, thus making with ISA devices or when one device creates multiple PCI devices, thus making

16
drivers/media/video/v4l2-device.c
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@ -49,6 +49,22 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev)
} }
EXPORT_SYMBOL_GPL(v4l2_device_register); EXPORT_SYMBOL_GPL(v4l2_device_register);
int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
atomic_t *instance)
{
int num = atomic_inc_return(instance) - 1;
int len = strlen(basename);
if (basename[len - 1] >= '0' && basename[len - 1] <= '9')
snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
"%s-%d", basename, num);
else
snprintf(v4l2_dev->name, sizeof(v4l2_dev->name),
"%s%d", basename, num);
return num;
}
EXPORT_SYMBOL_GPL(v4l2_device_set_name);
void v4l2_device_disconnect(struct v4l2_device *v4l2_dev) void v4l2_device_disconnect(struct v4l2_device *v4l2_dev)
{ {
if (v4l2_dev->dev) { if (v4l2_dev->dev) {

21
include/media/v4l2-device.h
View File

@ -53,10 +53,31 @@ struct v4l2_device {
dev may be NULL in rare cases (ISA devices). In that case you 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. */ 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); int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
/* Optional function to initialize the name field of struct v4l2_device using
the driver name and a driver-global atomic_t instance.
This function will increment the instance counter and returns the instance
value used in the name.
Example:
static atomic_t drv_instance = ATOMIC_INIT(0);
...
instance = v4l2_device_set_name(&v4l2_dev, "foo", &drv_instance);
The first time this is called the name field will be set to foo0 and
this function returns 0. If the name ends with a digit (e.g. cx18),
then the name will be set to cx18-0 since cx180 looks really odd. */
int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
atomic_t *instance);
/* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects. /* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects.
Since the parent disappears this ensures that v4l2_dev doesn't have an Since the parent disappears this ensures that v4l2_dev doesn't have an
invalid parent pointer. */ invalid parent pointer. */
void v4l2_device_disconnect(struct v4l2_device *v4l2_dev); void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
/* Unregister all sub-devices and any other resources related to v4l2_dev. */ /* Unregister all sub-devices and any other resources related to v4l2_dev. */
void v4l2_device_unregister(struct v4l2_device *v4l2_dev); void v4l2_device_unregister(struct v4l2_device *v4l2_dev);