drivers/media/radio/si470x/radio-si470x-usb.c

Source file repositories/reference/linux-study-clean/drivers/media/radio/si470x/radio-si470x-usb.c

File Facts

System
Linux kernel
Corpus path
drivers/media/radio/si470x/radio-si470x-usb.c
Extension
.c
Size
23725 bytes
Lines
850
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

if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSR) == 0) {
			/* No RDS group ready, better luck next time */
			goto resubmit;
		}
		if ((radio->registers[STATUSRSSI] & STATUSRSSI_RDSS) == 0) {
			/* RDS decoder not synchronized */
			goto resubmit;
		}
		for (blocknum = 0; blocknum < 4; blocknum++) {
			switch (blocknum) {
			default:
				bler = (radio->registers[STATUSRSSI] &
						STATUSRSSI_BLERA) >> 9;
				rds = radio->registers[RDSA];
				break;
			case 1:
				bler = (radio->registers[READCHAN] &
						READCHAN_BLERB) >> 14;
				rds = radio->registers[RDSB];
				break;
			case 2:
				bler = (radio->registers[READCHAN] &
						READCHAN_BLERC) >> 12;
				rds = radio->registers[RDSC];
				break;
			case 3:
				bler = (radio->registers[READCHAN] &
						READCHAN_BLERD) >> 10;
				rds = radio->registers[RDSD];
				break;
			}

			/* Fill the V4L2 RDS buffer */
			put_unaligned_le16(rds, &tmpbuf);
			tmpbuf[2] = blocknum;		/* offset name */
			tmpbuf[2] |= blocknum << 3;	/* received offset */
			if (bler > max_rds_errors)
				tmpbuf[2] |= 0x80; /* uncorrectable errors */
			else if (bler > 0)
				tmpbuf[2] |= 0x40; /* corrected error(s) */

			/* copy RDS block to internal buffer */
			memcpy(&radio->buffer[radio->wr_index], &tmpbuf, 3);
			radio->wr_index += 3;

			/* wrap write pointer */
			if (radio->wr_index >= radio->buf_size)
				radio->wr_index = 0;

			/* check for overflow */
			if (radio->wr_index == radio->rd_index) {
				/* increment and wrap read pointer */
				radio->rd_index += 3;
				if (radio->rd_index >= radio->buf_size)
					radio->rd_index = 0;
			}
		}
		if (radio->wr_index != radio->rd_index)
			wake_up_interruptible(&radio->read_queue);
	}

resubmit:
	/* Resubmit if we're still running. */
	if (radio->int_in_running && radio->usbdev) {
		retval = usb_submit_urb(radio->int_in_urb, GFP_ATOMIC);
		if (retval) {
			dev_warn(&radio->intf->dev,
			       "resubmitting urb failed (%d)", retval);
			radio->int_in_running = 0;
		}
	}
	radio->status_rssi_auto_update = radio->int_in_running;
}


static int si470x_fops_open(struct file *file)
{
	return v4l2_fh_open(file);
}

static int si470x_fops_release(struct file *file)
{
	return v4l2_fh_release(file);
}

static void si470x_usb_release(struct v4l2_device *v4l2_dev)
{
	struct si470x_device *radio =
		container_of(v4l2_dev, struct si470x_device, v4l2_dev);

Annotation

Implementation Notes