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Commit d7af78b9 authored by Kieran Bingham's avatar Kieran Bingham Committed by Felipe Balbi
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usb: gadget: uvc: Expose configuration name through video node 



When utilising multiple instantiations of a UVC gadget on a composite
device, there is no clear method to link a particular configuration to
its respective video node.

Provide a means for identifying the correct video node by exposing the
name of the function configuration through sysfs.

Reviewed-by: default avatarLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: default avatarKieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: default avatarFelipe Balbi <felipe.balbi@linux.intel.com>
parent c728effd

Documentation/ABI/testing/configfs-usb-gadget-uvc

+5 −0
Original line number Diff line number Diff line
@@ -263,3 +263,8 @@ Description: Specific streaming header descriptors 
					is connected

		bmInfo			- capabilities of this video streaming

					interface



What:		/sys/class/udc/udc.name/device/gadget/video4linux/video.name/function_name

Date:		May 2018

KernelVersion:	4.19

Description:	UVC configfs function instance name

drivers/usb/gadget/function/f_uvc.c

+23 −1
Original line number Diff line number Diff line
@@ -413,10 +413,21 @@ uvc_function_disconnect(struct uvc_device *uvc) 
 * USB probe and disconnect

 */



static ssize_t function_name_show(struct device *dev,

				  struct device_attribute *attr, char *buf)

{

	struct uvc_device *uvc = dev_get_drvdata(dev);



	return sprintf(buf, "%s\n", uvc->func.fi->group.cg_item.ci_name);

}



static DEVICE_ATTR_RO(function_name);



static int

uvc_register_video(struct uvc_device *uvc)

{

	struct usb_composite_dev *cdev = uvc->func.config->cdev;

	int ret;



	/* TODO reference counting. */

	uvc->vdev.v4l2_dev = &uvc->v4l2_dev;
@@ -429,7 +440,17 @@ uvc_register_video(struct uvc_device *uvc) 


	video_set_drvdata(&uvc->vdev, uvc);



	return video_register_device(&uvc->vdev, VFL_TYPE_GRABBER, -1);

	ret = video_register_device(&uvc->vdev, VFL_TYPE_GRABBER, -1);

	if (ret < 0)

		return ret;



	ret = device_create_file(&uvc->vdev.dev, &dev_attr_function_name);

	if (ret < 0) {

		video_unregister_device(&uvc->vdev);

		return ret;

	}



	return 0;

}



#define UVC_COPY_DESCRIPTOR(mem, dst, desc) \
@@ -867,6 +888,7 @@ static void uvc_unbind(struct usb_configuration *c, struct usb_function *f) 


	INFO(cdev, "%s\n", __func__);



	device_remove_file(&uvc->vdev.dev, &dev_attr_function_name);

	video_unregister_device(&uvc->vdev);

	v4l2_device_unregister(&uvc->v4l2_dev);