v4l2: add v4l2_device_set_name()

From: Hans Verkuil <hverkuil@xs4all.nl>

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

Priority: normal

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/linux/include/media/v4l2-device.h b/linux/include/media/v4l2-device.h
index 9afd39fb2..5d5d550e6 100644
--- a/linux/include/media/v4l2-device.h
+++ b/linux/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);