From d7af78b9245545908c90bce2206f200a4250b5db Mon Sep 17 00:00:00 2001 From: Kieran Bingham Date: Thu, 24 May 2018 17:16:12 +0100 Subject: [PATCH] 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: Laurent Pinchart Signed-off-by: Kieran Bingham Signed-off-by: Felipe Balbi --- .../ABI/testing/configfs-usb-gadget-uvc | 5 ++++ drivers/usb/gadget/function/f_uvc.c | 24 ++++++++++++++++++- 2 files changed, 28 insertions(+), 1 deletion(-) diff --git a/Documentation/ABI/testing/configfs-usb-gadget-uvc b/Documentation/ABI/testing/configfs-usb-gadget-uvc index 1ba0d0fda9c0..9281e2aa38df 100644 --- a/Documentation/ABI/testing/configfs-usb-gadget-uvc +++ b/Documentation/ABI/testing/configfs-usb-gadget-uvc @@ -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 diff --git a/drivers/usb/gadget/function/f_uvc.c b/drivers/usb/gadget/function/f_uvc.c index 1d2feac5c532..d8ce7868fe22 100644 --- a/drivers/usb/gadget/function/f_uvc.c +++ b/drivers/usb/gadget/function/f_uvc.c @@ -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); -- 2.30.2