Commit 102e7813 authored by Hans Verkuil's avatar Hans Verkuil Committed by Mauro Carvalho Chehab
Browse files

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



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

Signed-off-by: default avatarHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 416a7aa8

Documentation/video4linux/v4l2-framework.txt

+5 −0
Original line number Diff line number Diff line
@@ -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

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,

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

drivers/media/video/v4l2-device.c

+16 −0
Original line number Diff line number Diff line
@@ -49,6 +49,22 @@ int v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev) 
}

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)

{

	if (v4l2_dev->dev) {

include/media/v4l2-device.h

+21 −0
Original line number Diff line number Diff line
@@ -53,10 +53,31 @@ struct v4l2_device { 
   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);



/* 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.

   Since the parent disappears this ensures that v4l2_dev doesn't have an

   invalid parent pointer. */

void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);



/* Unregister all sub-devices and any other resources related to v4l2_dev. */

void v4l2_device_unregister(struct v4l2_device *v4l2_dev);