drivers/media/usb/em28xx/em28xx-vbi.c

Source file repositories/reference/linux-study-clean/drivers/media/usb/em28xx/em28xx-vbi.c

File Facts

System
Linux kernel
Corpus path
drivers/media/usb/em28xx/em28xx-vbi.c
Extension
.c
Size
2172 bytes
Lines
88
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

// SPDX-License-Identifier: GPL-2.0+
//
// em28xx-vbi.c - VBI driver for em28xx
//
// Copyright (C) 2009 Devin Heitmueller <dheitmueller@kernellabs.com>
//
// This work was sponsored by EyeMagnet Limited.

#include "em28xx.h"

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/hardirq.h>
#include <linux/init.h>
#include <linux/usb.h>

#include "em28xx-v4l.h"

/* ------------------------------------------------------------------ */

static int vbi_queue_setup(struct vb2_queue *vq,
			   unsigned int *nbuffers, unsigned int *nplanes,
			   unsigned int sizes[], struct device *alloc_devs[])
{
	struct em28xx *dev = vb2_get_drv_priv(vq);
	struct em28xx_v4l2 *v4l2 = dev->v4l2;
	unsigned long size = v4l2->vbi_width * v4l2->vbi_height * 2;

	if (*nbuffers < 2)
		*nbuffers = 2;

	if (*nplanes) {
		if (sizes[0] < size)
			return -EINVAL;
		size = sizes[0];
	}

	*nplanes = 1;
	sizes[0] = size;

	return 0;
}

static int vbi_buffer_prepare(struct vb2_buffer *vb)
{
	struct em28xx        *dev  = vb2_get_drv_priv(vb->vb2_queue);
	struct em28xx_v4l2   *v4l2 = dev->v4l2;
	unsigned long        size;

	size = v4l2->vbi_width * v4l2->vbi_height * 2;

	if (vb2_plane_size(vb, 0) < size) {
		dev_info(&dev->intf->dev,
			 "%s data will not fit into plane (%lu < %lu)\n",
			 __func__, vb2_plane_size(vb, 0), size);
		return -EINVAL;
	}
	vb2_set_plane_payload(vb, 0, size);

	return 0;
}

static void
vbi_buffer_queue(struct vb2_buffer *vb)
{
	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
	struct em28xx *dev = vb2_get_drv_priv(vb->vb2_queue);
	struct em28xx_buffer *buf =
		container_of(vbuf, struct em28xx_buffer, vb);
	struct em28xx_dmaqueue *vbiq = &dev->vbiq;
	unsigned long flags = 0;

	buf->mem = vb2_plane_vaddr(vb, 0);
	buf->length = vb2_plane_size(vb, 0);

	spin_lock_irqsave(&dev->slock, flags);
	list_add_tail(&buf->list, &vbiq->active);
	spin_unlock_irqrestore(&dev->slock, flags);
}

const struct vb2_ops em28xx_vbi_qops = {
	.queue_setup    = vbi_queue_setup,
	.buf_prepare    = vbi_buffer_prepare,
	.buf_queue      = vbi_buffer_queue,
	.start_streaming = em28xx_start_analog_streaming,
	.stop_streaming = em28xx_stop_vbi_streaming,
};

Annotation

Implementation Notes