diff options
| -rw-r--r-- | Documentation/video4linux/v4l2-framework.txt | 5 | ||||
| -rw-r--r-- | drivers/media/video/v4l2-device.c | 16 | ||||
| -rw-r--r-- | include/media/v4l2-device.h | 21 |
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); |