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-rw-r--r--Documentation/video4linux/v4l2-framework.txt5
-rw-r--r--drivers/media/video/v4l2-device.c16
-rw-r--r--include/media/v4l2-device.h21
3 files changed, 42 insertions, 0 deletions
diff --git a/Documentation/video4linux/v4l2-framework.txt b/Documentation/video4linux/v4l2-framework.txt
index 854808b67fae..d54c1e4c6a9c 100644
--- a/Documentation/video4linux/v4l2-framework.txt
+++ b/Documentation/video4linux/v4l2-framework.txt
@@ -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
diff --git a/drivers/media/video/v4l2-device.c b/drivers/media/video/v4l2-device.c
index 94aa485ade52..ffb425f7c24c 100644
--- a/drivers/media/video/v4l2-device.c
+++ b/drivers/media/video/v4l2-device.c
@@ -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) {
diff --git a/include/media/v4l2-device.h b/include/media/v4l2-device.h
index 9afd39fb2cfc..5d5d550e63ad 100644
--- a/include/media/v4l2-device.h
+++ b/include/media/v4l2-device.h
@@ -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);