drivers/media/usb/usbtv/usbtv-core.c

Source file repositories/reference/linux-study-clean/drivers/media/usb/usbtv/usbtv-core.c

File Facts

System
Linux kernel
Corpus path
drivers/media/usb/usbtv/usbtv-core.c
Extension
.c
Size
4749 bytes
Lines
166
Domain
Driver Families
Bucket
drivers/media
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

#include "usbtv.h"

int usbtv_set_regs(struct usbtv *usbtv, const u16 regs[][2], int size)
{
	int ret;
	int pipe = usb_sndctrlpipe(usbtv->udev, 0);
	int i;

	for (i = 0; i < size; i++) {
		u16 index = regs[i][0];
		u16 value = regs[i][1];

		ret = usb_control_msg(usbtv->udev, pipe, USBTV_REQUEST_REG,
			USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
			value, index, NULL, 0, USB_CTRL_GET_TIMEOUT);
		if (ret < 0)
			return ret;
	}

	return 0;
}

static int usbtv_probe(struct usb_interface *intf,
	const struct usb_device_id *id)
{
	int ret;
	int size;
	struct device *dev = &intf->dev;
	struct usbtv *usbtv;
	struct usb_host_endpoint *ep;

	/* Checks that the device is what we think it is. */
	if (intf->num_altsetting != 2)
		return -ENODEV;
	if (intf->altsetting[1].desc.bNumEndpoints != 4)
		return -ENODEV;

	ep = &intf->altsetting[1].endpoint[0];

	/* Packet size is split into 11 bits of base size and count of
	 * extra multiplies of it.*/
	size = usb_endpoint_maxp(&ep->desc);
	size = size * usb_endpoint_maxp_mult(&ep->desc);

	/* Device structure */
	usbtv = kzalloc_obj(struct usbtv);
	if (usbtv == NULL)
		return -ENOMEM;
	usbtv->dev = dev;
	usbtv->udev = interface_to_usbdev(intf);

	usbtv->iso_size = size;

	usb_set_intfdata(intf, usbtv);

	ret = usbtv_video_init(usbtv);
	if (ret < 0)
		goto usbtv_video_fail;

	ret = usbtv_audio_init(usbtv);
	if (ret < 0)
		goto usbtv_audio_fail;

	/* for simplicity we exploit the v4l2_device reference counting */
	v4l2_device_get(&usbtv->v4l2_dev);

	dev_info(dev, "Fushicai USBTV007 Audio-Video Grabber\n");
	return 0;

usbtv_audio_fail:
	/* we must not free at this point */
	v4l2_device_get(&usbtv->v4l2_dev);
	/* this will undo the v4l2_device_get() */
	usbtv_video_free(usbtv);

usbtv_video_fail:
	usb_set_intfdata(intf, NULL);
	kfree(usbtv);

	return ret;
}

static void usbtv_disconnect(struct usb_interface *intf)
{
	struct usbtv *usbtv = usb_get_intfdata(intf);

	usb_set_intfdata(intf, NULL);

	if (!usbtv)
		return;

Annotation

Implementation Notes