[media] Add the via framebuffer camera controller driver

Add a driver for the video capture port on VIA integrated chipsets.  This
version has a remaining OLPCism or two and expects to be talking to an
ov7670; those can be improved as the need arises.

This work was supported by the One Laptop Per Child project.
Thanks to Laurent Pinchart for a number of useful comments.

Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

4 files changed, 1579 insertions, 0 deletions

diff --git a/drivers/media/video/Kconfig b/drivers/media/video/Kconfig
index 2d4226710ed5..0efbb29a1a08 100644
--- a/drivers/media/video/Kconfig
+++ b/drivers/media/video/Kconfig
@@ -712,6 +712,16 @@ config VIDEO_SR030PC30
 	---help---
 	  This driver supports SR030PC30 VGA camera from Siliconfile
 
+config VIDEO_VIA_CAMERA
+	tristate "VIAFB camera controller support"
+	depends on FB_VIA
+	select VIDEOBUF_DMA_SG
+	select VIDEO_OV7670
+	help
+	   Driver support for the integrated camera controller in VIA
+	   Chrome9 chipsets.  Currently only tested on OLPC xo-1.5 systems
+	   with ov7670 sensors.
+
 config SOC_CAMERA
 	tristate "SoC camera support"
 	depends on VIDEO_V4L2 && HAS_DMA && I2C
diff --git a/drivers/media/video/Makefile b/drivers/media/video/Makefile
index d5e49ddbf9dd..af79d476a4c8 100644
--- a/drivers/media/video/Makefile
+++ b/drivers/media/video/Makefile
@@ -122,6 +122,8 @@ obj-$(CONFIG_VIDEO_CX2341X) += cx2341x.o
 
 obj-$(CONFIG_VIDEO_CAFE_CCIC) += cafe_ccic.o
 
+obj-$(CONFIG_VIDEO_VIA_CAMERA) += via-camera.o
+
 obj-$(CONFIG_USB_DABUSB)        += dabusb.o
 obj-$(CONFIG_USB_SE401)         += se401.o
 obj-$(CONFIG_USB_ZR364XX)       += zr364xx.o
diff --git a/drivers/media/video/via-camera.c b/drivers/media/video/via-camera.c
new file mode 100644
index 000000000000..02a21bccae18
--- /dev/null
+++ b/drivers/media/video/via-camera.c
@@ -0,0 +1,1474 @@
+/*
+ * Driver for the VIA Chrome integrated camera controller.
+ *
+ * Copyright 2009,2010 Jonathan Corbet <corbet@lwn.net>
+ * Distributable under the terms of the GNU General Public License, version 2
+ *
+ * This work was supported by the One Laptop Per Child project
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/pci.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/videodev2.h>
+#include <media/v4l2-device.h>
+#include <media/v4l2-ioctl.h>
+#include <media/v4l2-chip-ident.h>
+#include <media/videobuf-dma-sg.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/pm_qos_params.h>
+#include <linux/via-core.h>
+#include <linux/via-gpio.h>
+#include <linux/via_i2c.h>
+
+#include "via-camera.h"
+
+MODULE_AUTHOR("Jonathan Corbet <corbet@lwn.net>");
+MODULE_DESCRIPTION("VIA framebuffer-based camera controller driver");
+MODULE_LICENSE("GPL");
+
+static int flip_image;
+module_param(flip_image, bool, 0444);
+MODULE_PARM_DESC(flip_image,
+		"If set, the sensor will be instructed to flip the image "
+		"vertically.");
+
+#ifdef CONFIG_OLPC_XO_1_5
+static int override_serial;
+module_param(override_serial, bool, 0444);
+MODULE_PARM_DESC(override_serial,
+		"The camera driver will normally refuse to load if "
+		"the XO 1.5 serial port is enabled.  Set this option "
+		"to force the issue.");
+#endif
+
+/*
+ * Basic window sizes.
+ */
+#define VGA_WIDTH	640
+#define VGA_HEIGHT	480
+#define QCIF_WIDTH	176
+#define	QCIF_HEIGHT	144
+
+/*
+ * The structure describing our camera.
+ */
+enum viacam_opstate { S_IDLE = 0, S_RUNNING = 1 };
+
+struct via_camera {
+	struct v4l2_device v4l2_dev;
+	struct video_device vdev;
+	struct v4l2_subdev *sensor;
+	struct platform_device *platdev;
+	struct viafb_dev *viadev;
+	struct mutex lock;
+	enum viacam_opstate opstate;
+	unsigned long flags;
+	struct pm_qos_request_list qos_request;
+	/*
+	 * GPIO info for power/reset management
+	 */
+	int power_gpio;
+	int reset_gpio;
+	/*
+	 * I/O memory stuff.
+	 */
+	void __iomem *mmio;	/* Where the registers live */
+	void __iomem *fbmem;	/* Frame buffer memory */
+	u32 fb_offset;		/* Reserved memory offset (FB) */
+	/*
+	 * Capture buffers and related.	 The controller supports
+	 * up to three, so that's what we have here.  These buffers
+	 * live in frame buffer memory, so we don't call them "DMA".
+	 */
+	unsigned int cb_offsets[3];	/* offsets into fb mem */
+	u8 *cb_addrs[3];		/* Kernel-space addresses */
+	int n_cap_bufs;			/* How many are we using? */
+	int next_buf;
+	struct videobuf_queue vb_queue;
+	struct list_head buffer_queue;	/* prot. by reg_lock */
+	/*
+	 * User tracking.
+	 */
+	int users;
+	struct file *owner;
+	/*
+	 * Video format information.  sensor_format is kept in a form
+	 * that we can use to pass to the sensor.  We always run the
+	 * sensor in VGA resolution, though, and let the controller
+	 * downscale things if need be.	 So we keep the "real*
+	 * dimensions separately.
+	 */
+	struct v4l2_pix_format sensor_format;
+	struct v4l2_pix_format user_format;
+	enum v4l2_mbus_pixelcode mbus_code;
+};
+
+/*
+ * Yes, this is a hack, but there's only going to be one of these
+ * on any system we know of.
+ */
+static struct via_camera *via_cam_info;
+
+/*
+ * Flag values, manipulated with bitops
+ */
+#define CF_DMA_ACTIVE	 0	/* A frame is incoming */
+#define CF_CONFIG_NEEDED 1	/* Must configure hardware */
+
+
+/*
+ * Nasty ugly v4l2 boilerplate.
+ */
+#define sensor_call(cam, optype, func, args...) \
+	v4l2_subdev_call(cam->sensor, optype, func, ##args)
+
+/*
+ * Debugging and related.
+ */
+#define cam_err(cam, fmt, arg...) \
+	dev_err(&(cam)->platdev->dev, fmt, ##arg);
+#define cam_warn(cam, fmt, arg...) \
+	dev_warn(&(cam)->platdev->dev, fmt, ##arg);
+#define cam_dbg(cam, fmt, arg...) \
+	dev_dbg(&(cam)->platdev->dev, fmt, ##arg);
+
+/*
+ * Format handling.  This is ripped almost directly from Hans's changes
+ * to cafe_ccic.c.  It's a little unfortunate; until this change, we
+ * didn't need to know anything about the format except its byte depth;
+ * now this information must be managed at this level too.
+ */
+static struct via_format {
+	__u8 *desc;
+	__u32 pixelformat;
+	int bpp;   /* Bytes per pixel */
+	enum v4l2_mbus_pixelcode mbus_code;
+} via_formats[] = {
+	{
+		.desc		= "YUYV 4:2:2",
+		.pixelformat	= V4L2_PIX_FMT_YUYV,
+		.mbus_code	= V4L2_MBUS_FMT_YUYV8_2X8,
+		.bpp		= 2,
+	},
+	{
+		.desc		= "RGB 565",
+		.pixelformat	= V4L2_PIX_FMT_RGB565,
+		.mbus_code	= V4L2_MBUS_FMT_RGB565_2X8_LE,
+		.bpp		= 2,
+	},
+	/* RGB444 and Bayer should be doable, but have never been
+	   tested with this driver. */
+};
+#define N_VIA_FMTS ARRAY_SIZE(via_formats)
+
+static struct via_format *via_find_format(u32 pixelformat)
+{
+	unsigned i;
+
+	for (i = 0; i < N_VIA_FMTS; i++)
+		if (via_formats[i].pixelformat == pixelformat)
+			return via_formats + i;
+	/* Not found? Then return the first format. */
+	return via_formats;
+}
+
+
+/*--------------------------------------------------------------------------*/
+/*
+ * Sensor power/reset management.  This piece is OLPC-specific for
+ * sure; other configurations will have things connected differently.
+ */
+static int via_sensor_power_setup(struct via_camera *cam)
+{
+	int ret;
+
+	cam->power_gpio = viafb_gpio_lookup("VGPIO3");
+	cam->reset_gpio = viafb_gpio_lookup("VGPIO2");
+	if (cam->power_gpio < 0 || cam->reset_gpio < 0) {
+		dev_err(&cam->platdev->dev, "Unable to find GPIO lines\n");
+		return -EINVAL;
+	}
+	ret = gpio_request(cam->power_gpio, "viafb-camera");
+	if (ret) {
+		dev_err(&cam->platdev->dev, "Unable to request power GPIO\n");
+		return ret;
+	}
+	ret = gpio_request(cam->reset_gpio, "viafb-camera");
+	if (ret) {
+		dev_err(&cam->platdev->dev, "Unable to request reset GPIO\n");
+		gpio_free(cam->power_gpio);
+		return ret;
+	}
+	gpio_direction_output(cam->power_gpio, 0);
+	gpio_direction_output(cam->reset_gpio, 0);
+	return 0;
+}
+
+/*
+ * Power up the sensor and perform the reset dance.
+ */
+static void via_sensor_power_up(struct via_camera *cam)
+{
+	gpio_set_value(cam->power_gpio, 1);
+	gpio_set_value(cam->reset_gpio, 0);
+	msleep(20);  /* Probably excessive */
+	gpio_set_value(cam->reset_gpio, 1);
+	msleep(20);
+}
+
+static void via_sensor_power_down(struct via_camera *cam)
+{
+	gpio_set_value(cam->power_gpio, 0);
+	gpio_set_value(cam->reset_gpio, 0);
+}
+
+
+static void via_sensor_power_release(struct via_camera *cam)
+{
+	via_sensor_power_down(cam);
+	gpio_free(cam->power_gpio);
+	gpio_free(cam->reset_gpio);
+}
+
+/* --------------------------------------------------------------------------*/
+/* Sensor ops */
+
+/*
+ * Manage the ov7670 "flip" bit, which needs special help.
+ */
+static int viacam_set_flip(struct via_camera *cam)
+{
+	struct v4l2_control ctrl;
+
+	memset(&ctrl, 0, sizeof(ctrl));
+	ctrl.id = V4L2_CID_VFLIP;
+	ctrl.value = flip_image;
+	return sensor_call(cam, core, s_ctrl, &ctrl);
+}
+
+/*
+ * Configure the sensor.  It's up to the caller to ensure
+ * that the camera is in the correct operating state.
+ */
+static int viacam_configure_sensor(struct via_camera *cam)
+{
+	struct v4l2_mbus_framefmt mbus_fmt;
+	int ret;
+
+	v4l2_fill_mbus_format(&mbus_fmt, &cam->sensor_format, cam->mbus_code);
+	ret = sensor_call(cam, core, init, 0);
+	if (ret == 0)
+		ret = sensor_call(cam, video, s_mbus_fmt, &mbus_fmt);
+	/*
+	 * OV7670 does weird things if flip is set *before* format...
+	 */
+	if (ret == 0)
+		ret = viacam_set_flip(cam);
+	return ret;
+}
+
+
+
+/* --------------------------------------------------------------------------*/
+/*
+ * Some simple register accessors; they assume that the lock is held.
+ *
+ * Should we want to support the second capture engine, we could
+ * hide the register difference by adding 0x1000 to registers in the
+ * 0x300-350 range.
+ */
+static inline void viacam_write_reg(struct via_camera *cam,
+		int reg, int value)
+{
+	iowrite32(value, cam->mmio + reg);
+}
+
+static inline int viacam_read_reg(struct via_camera *cam, int reg)
+{
+	return ioread32(cam->mmio + reg);
+}
+
+static inline void viacam_write_reg_mask(struct via_camera *cam,
+		int reg, int value, int mask)
+{
+	int tmp = viacam_read_reg(cam, reg);
+
+	tmp = (tmp & ~mask) | (value & mask);
+	viacam_write_reg(cam, reg, tmp);
+}
+
+
+/* --------------------------------------------------------------------------*/
+/* Interrupt management and handling */
+
+static irqreturn_t viacam_quick_irq(int irq, void *data)
+{
+	struct via_camera *cam = data;
+	irqreturn_t ret = IRQ_NONE;
+	int icv;
+
+	/*
+	 * All we do here is to clear the interrupts and tell
+	 * the handler thread to wake up.
+	 */
+	spin_lock(&cam->viadev->reg_lock);
+	icv = viacam_read_reg(cam, VCR_INTCTRL);
+	if (icv & VCR_IC_EAV) {
+		icv |= VCR_IC_EAV|VCR_IC_EVBI|VCR_IC_FFULL;
+		viacam_write_reg(cam, VCR_INTCTRL, icv);
+		ret = IRQ_WAKE_THREAD;
+	}
+	spin_unlock(&cam->viadev->reg_lock);
+	return ret;
+}
+
+/*
+ * Find the next videobuf buffer which has somebody waiting on it.
+ */
+static struct videobuf_buffer *viacam_next_buffer(struct via_camera *cam)
+{
+	unsigned long flags;
+	struct videobuf_buffer *buf = NULL;
+
+	spin_lock_irqsave(&cam->viadev->reg_lock, flags);
+	if (cam->opstate != S_RUNNING)
+		goto out;
+	if (list_empty(&cam->buffer_queue))
+		goto out;
+	buf = list_entry(cam->buffer_queue.next, struct videobuf_buffer, queue);
+	if (!waitqueue_active(&buf->done)) {/* Nobody waiting */
+		buf = NULL;
+		goto out;
+	}
+	list_del(&buf->queue);
+	buf->state = VIDEOBUF_ACTIVE;
+out:
+	spin_unlock_irqrestore(&cam->viadev->reg_lock, flags);
+	return buf;
+}
+
+/*
+ * The threaded IRQ handler.
+ */
+static irqreturn_t viacam_irq(int irq, void *data)
+{
+	int bufn;
+	struct videobuf_buffer *vb;
+	struct via_camera *cam = data;
+	struct videobuf_dmabuf *vdma;
+
+	/*
+	 * If there is no place to put the data frame, don't bother
+	 * with anything else.
+	 */
+	vb = viacam_next_buffer(cam);
+	if (vb == NULL)
+		goto done;
+	/*
+	 * Figure out which buffer we just completed.
+	 */
+	bufn = (viacam_read_reg(cam, VCR_INTCTRL) & VCR_IC_ACTBUF) >> 3;
+	bufn -= 1;
+	if (bufn < 0)
+		bufn = cam->n_cap_bufs - 1;
+	/*
+	 * Copy over the data and let any waiters know.
+	 */
+	vdma = videobuf_to_dma(vb);
+	viafb_dma_copy_out_sg(cam->cb_offsets[bufn], vdma->sglist, vdma->sglen);
+	vb->state = VIDEOBUF_DONE;
+	vb->size = cam->user_format.sizeimage;
+	wake_up(&vb->done);
+done:
+	return IRQ_HANDLED;
+}
+
+
+/*
+ * These functions must mess around with the general interrupt
+ * control register, which is relevant to much more than just the
+ * camera.  Nothing else uses interrupts, though, as of this writing.
+ * Should that situation change, we'll have to improve support at
+ * the via-core level.
+ */
+static void viacam_int_enable(struct via_camera *cam)
+{
+	viacam_write_reg(cam, VCR_INTCTRL,
+			VCR_IC_INTEN|VCR_IC_EAV|VCR_IC_EVBI|VCR_IC_FFULL);
+	viafb_irq_enable(VDE_I_C0AVEN);
+}
+
+static void viacam_int_disable(struct via_camera *cam)
+{
+	viafb_irq_disable(VDE_I_C0AVEN);
+	viacam_write_reg(cam, VCR_INTCTRL, 0);
+}
+
+
+
+/* --------------------------------------------------------------------------*/
+/* Controller operations */
+
+/*
+ * Set up our capture buffers in framebuffer memory.
+ */
+static int viacam_ctlr_cbufs(struct via_camera *cam)
+{
+	int nbuf = cam->viadev->camera_fbmem_size/cam->sensor_format.sizeimage;
+	int i;
+	unsigned int offset;
+
+	/*
+	 * See how many buffers we can work with.
+	 */
+	if (nbuf >= 3) {
+		cam->n_cap_bufs = 3;
+		viacam_write_reg_mask(cam, VCR_CAPINTC, VCR_CI_3BUFS,
+				VCR_CI_3BUFS);
+	} else if (nbuf == 2) {
+		cam->n_cap_bufs = 2;
+		viacam_write_reg_mask(cam, VCR_CAPINTC, 0, VCR_CI_3BUFS);
+	} else {
+		cam_warn(cam, "Insufficient frame buffer memory\n");
+		return -ENOMEM;
+	}
+	/*
+	 * Set them up.
+	 */
+	offset = cam->fb_offset;
+	for (i = 0; i < cam->n_cap_bufs; i++) {
+		cam->cb_offsets[i] = offset;
+		cam->cb_addrs[i] = cam->fbmem + offset;
+		viacam_write_reg(cam, VCR_VBUF1 + i*4, offset & VCR_VBUF_MASK);
+		offset += cam->sensor_format.sizeimage;
+	}
+	return 0;
+}
+
+/*
+ * Set the scaling register for downscaling the image.
+ *
+ * This register works like this...  Vertical scaling is enabled
+ * by bit 26; if that bit is set, downscaling is controlled by the
+ * value in bits 16:25.	 Those bits are divided by 1024 to get
+ * the scaling factor; setting just bit 25 thus cuts the height
+ * in half.
+ *
+ * Horizontal scaling works about the same, but it's enabled by
+ * bit 11, with bits 0:10 giving the numerator of a fraction
+ * (over 2048) for the scaling value.
+ *
+ * This function is naive in that, if the user departs from
+ * the 3x4 VGA scaling factor, the image will distort.	We
+ * could work around that if it really seemed important.
+ */
+static void viacam_set_scale(struct via_camera *cam)
+{
+	unsigned int avscale;
+	int sf;
+
+	if (cam->user_format.width == VGA_WIDTH)
+		avscale = 0;
+	else {
+		sf = (cam->user_format.width*2048)/VGA_WIDTH;
+		avscale = VCR_AVS_HEN | sf;
+	}
+	if (cam->user_format.height < VGA_HEIGHT) {
+		sf = (1024*cam->user_format.height)/VGA_HEIGHT;
+		avscale |= VCR_AVS_VEN | (sf << 16);
+	}
+	viacam_write_reg(cam, VCR_AVSCALE, avscale);
+}
+
+
+/*
+ * Configure image-related information into the capture engine.
+ */
+static void viacam_ctlr_image(struct via_camera *cam)
+{
+	int cicreg;
+
+	/*
+	 * Disable clock before messing with stuff - from the via
+	 * sample driver.
+	 */
+	viacam_write_reg(cam, VCR_CAPINTC, ~(VCR_CI_ENABLE|VCR_CI_CLKEN));
+	/*
+	 * Set up the controller for VGA resolution, modulo magic
+	 * offsets from the via sample driver.
+	 */
+	viacam_write_reg(cam, VCR_HORRANGE, 0x06200120);
+	viacam_write_reg(cam, VCR_VERTRANGE, 0x01de0000);
+	viacam_set_scale(cam);
+	/*
+	 * Image size info.
+	 */
+	viacam_write_reg(cam, VCR_MAXDATA,
+			(cam->sensor_format.height << 16) |
+			(cam->sensor_format.bytesperline >> 3));
+	viacam_write_reg(cam, VCR_MAXVBI, 0);
+	viacam_write_reg(cam, VCR_VSTRIDE,
+			cam->user_format.bytesperline & VCR_VS_STRIDE);
+	/*
+	 * Set up the capture interface control register,
+	 * everything but the "go" bit.
+	 *
+	 * The FIFO threshold is a bit of a magic number; 8 is what
+	 * VIA's sample code uses.
+	 */
+	cicreg = VCR_CI_CLKEN |
+		0x08000000 |		/* FIFO threshold */
+		VCR_CI_FLDINV |		/* OLPC-specific? */
+		VCR_CI_VREFINV |	/* OLPC-specific? */
+		VCR_CI_DIBOTH |		/* Capture both fields */
+		VCR_CI_CCIR601_8;
+	if (cam->n_cap_bufs == 3)
+		cicreg |= VCR_CI_3BUFS;
+	/*
+	 * YUV formats need different byte swapping than RGB.
+	 */
+	if (cam->user_format.pixelformat == V4L2_PIX_FMT_YUYV)
+		cicreg |= VCR_CI_YUYV;
+	else
+		cicreg |= VCR_CI_UYVY;
+	viacam_write_reg(cam, VCR_CAPINTC, cicreg);
+}
+
+
+static int viacam_config_controller(struct via_camera *cam)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&cam->viadev->reg_lock, flags);
+	ret = viacam_ctlr_cbufs(cam);
+	if (!ret)
+		viacam_ctlr_image(cam);
+	spin_unlock_irqrestore(&cam->viadev->reg_lock, flags);
+	clear_bit(CF_CONFIG_NEEDED, &cam->flags);
+	return ret;
+}
+
+/*
+ * Make it start grabbing data.
+ */
+static void viacam_start_engine(struct via_camera *cam)
+{
+	spin_lock_irq(&cam->viadev->reg_lock);
+	cam->next_buf = 0;
+	viacam_write_reg_mask(cam, VCR_CAPINTC, VCR_CI_ENABLE, VCR_CI_ENABLE);
+	viacam_int_enable(cam);
+	(void) viacam_read_reg(cam, VCR_CAPINTC); /* Force post */
+	cam->opstate = S_RUNNING;
+	spin_unlock_irq(&cam->viadev->reg_lock);
+}
+
+
+static void viacam_stop_engine(struct via_camera *cam)
+{
+	spin_lock_irq(&cam->viadev->reg_lock);
+	viacam_int_disable(cam);
+	viacam_write_reg_mask(cam, VCR_CAPINTC, 0, VCR_CI_ENABLE);
+	(void) viacam_read_reg(cam, VCR_CAPINTC); /* Force post */
+	cam->opstate = S_IDLE;
+	spin_unlock_irq(&cam->viadev->reg_lock);
+}
+
+
+/* --------------------------------------------------------------------------*/
+/* Videobuf callback ops */
+
+/*
+ * buffer_setup.  The purpose of this one would appear to be to tell
+ * videobuf how big a single image is.	It's also evidently up to us
+ * to put some sort of limit on the maximum number of buffers allowed.
+ */
+static int viacam_vb_buf_setup(struct videobuf_queue *q,
+		unsigned int *count, unsigned int *size)
+{
+	struct via_camera *cam = q->priv_data;
+
+	*size = cam->user_format.sizeimage;
+	if (*count == 0 || *count > 6)	/* Arbitrary number */
+		*count = 6;
+	return 0;
+}
+
+/*
+ * Prepare a buffer.
+ */
+static int viacam_vb_buf_prepare(struct videobuf_queue *q,
+		struct videobuf_buffer *vb, enum v4l2_field field)
+{
+	struct via_camera *cam = q->priv_data;
+
+	vb->size = cam->user_format.sizeimage;
+	vb->width = cam->user_format.width; /* bytesperline???? */
+	vb->height = cam->user_format.height;
+	vb->field = field;
+	if (vb->state == VIDEOBUF_NEEDS_INIT) {
+		int ret = videobuf_iolock(q, vb, NULL);
+		if (ret)
+			return ret;
+	}
+	vb->state = VIDEOBUF_PREPARED;
+	return 0;
+}
+
+/*
+ * We've got a buffer to put data into.
+ *
+ * FIXME: check for a running engine and valid buffers?
+ */
+static void viacam_vb_buf_queue(struct videobuf_queue *q,
+		struct videobuf_buffer *vb)
+{
+	struct via_camera *cam = q->priv_data;
+
+	/*
+	 * Note that videobuf holds the lock when it calls
+	 * us, so we need not (indeed, cannot) take it here.
+	 */
+	vb->state = VIDEOBUF_QUEUED;
+	list_add_tail(&vb->queue, &cam->buffer_queue);
+}
+
+/*
+ * Free a buffer.
+ */
+static void viacam_vb_buf_release(struct videobuf_queue *q,
+		struct videobuf_buffer *vb)
+{
+	struct via_camera *cam = q->priv_data;
+
+	videobuf_dma_unmap(&cam->platdev->dev, videobuf_to_dma(vb));
+	videobuf_dma_free(videobuf_to_dma(vb));
+	vb->state = VIDEOBUF_NEEDS_INIT;
+}
+
+static const struct videobuf_queue_ops viacam_vb_ops = {
+	.buf_setup	= viacam_vb_buf_setup,
+	.buf_prepare	= viacam_vb_buf_prepare,
+	.buf_queue	= viacam_vb_buf_queue,
+	.buf_release	= viacam_vb_buf_release,
+};
+
+/* --------------------------------------------------------------------------*/
+/* File operations */
+
+static int viacam_open(struct file *filp)
+{
+	struct via_camera *cam = video_drvdata(filp);
+
+	filp->private_data = cam;
+	/*
+	 * Note the new user.  If this is the first one, we'll also
+	 * need to power up the sensor.
+	 */
+	mutex_lock(&cam->lock);
+	if (cam->users == 0) {
+		int ret = viafb_request_dma();
+
+		if (ret) {
+			mutex_unlock(&cam->lock);
+			return ret;
+		}
+		via_sensor_power_up(cam);
+		set_bit(CF_CONFIG_NEEDED, &cam->flags);
+		/*
+		 * Hook into videobuf.	Evidently this cannot fail.
+		 */
+		videobuf_queue_sg_init(&cam->vb_queue, &viacam_vb_ops,
+				&cam->platdev->dev, &cam->viadev->reg_lock,
+				V4L2_BUF_TYPE_VIDEO_CAPTURE, V4L2_FIELD_NONE,
+				sizeof(struct videobuf_buffer), cam, NULL);
+	}
+	(cam->users)++;
+	mutex_unlock(&cam->lock);
+	return 0;
+}
+
+static int viacam_release(struct file *filp)
+{
+	struct via_camera *cam = video_drvdata(filp);
+
+	mutex_lock(&cam->lock);
+	(cam->users)--;
+	/*
+	 * If the "owner" is closing, shut down any ongoing
+	 * operations.
+	 */
+	if (filp == cam->owner) {
+		videobuf_stop(&cam->vb_queue);
+		/*
+		 * We don't hold the spinlock here, but, if release()
+		 * is being called by the owner, nobody else will
+		 * be changing the state.  And an extra stop would
+		 * not hurt anyway.
+		 */
+		if (cam->opstate != S_IDLE)
+			viacam_stop_engine(cam);
+		cam->owner = NULL;
+	}
+	/*
+	 * Last one out needs to turn out the lights.
+	 */
+	if (cam->users == 0) {
+		videobuf_mmap_free(&cam->vb_queue);
+		via_sensor_power_down(cam);
+		viafb_release_dma();
+	}
+	mutex_unlock(&cam->lock);
+	return 0;
+}
+
+/*
+ * Read a frame from the device.
+ */
+static ssize_t viacam_read(struct file *filp, char __user *buffer,
+		size_t len, loff_t *pos)
+{
+	struct via_camera *cam = video_drvdata(filp);
+	int ret;
+
+	mutex_lock(&cam->lock);
+	/*
+	 * Enforce the V4l2 "only one owner gets to read data" rule.
+	 */
+	if (cam->owner && cam->owner != filp) {
+		ret = -EBUSY;
+		goto out_unlock;
+	}
+	cam->owner = filp;
+	/*
+	 * Do we need to configure the hardware?
+	 */
+	if (test_bit(CF_CONFIG_NEEDED, &cam->flags)) {
+		ret = viacam_configure_sensor(cam);
+		if (!ret)
+			ret = viacam_config_controller(cam);
+		if (ret)
+			goto out_unlock;
+	}
+	/*
+	 * Fire up the capture engine, then have videobuf do
+	 * the heavy lifting.  Someday it would be good to avoid
+	 * stopping and restarting the engine each time.
+	 */
+	INIT_LIST_HEAD(&cam->buffer_queue);
+	viacam_start_engine(cam);
+	ret = videobuf_read_stream(&cam->vb_queue, buffer, len, pos, 0,
+			filp->f_flags & O_NONBLOCK);
+	viacam_stop_engine(cam);
+	/* videobuf_stop() ?? */
+
+out_unlock:
+	mutex_unlock(&cam->lock);
+	return ret;
+}
+
+
+static unsigned int viacam_poll(struct file *filp, struct poll_table_struct *pt)
+{
+	struct via_camera *cam = video_drvdata(filp);
+
+	return videobuf_poll_stream(filp, &cam->vb_queue, pt);
+}
+
+
+static int viacam_mmap(struct file *filp, struct vm_area_struct *vma)
+{
+	struct via_camera *cam = video_drvdata(filp);
+
+	return videobuf_mmap_mapper(&cam->vb_queue, vma);
+}
+
+
+
+static const struct v4l2_file_operations viacam_fops = {
+	.owner		= THIS_MODULE,
+	.open		= viacam_open,
+	.release	= viacam_release,
+	.read		= viacam_read,
+	.poll		= viacam_poll,
+	.mmap		= viacam_mmap,
+	.unlocked_ioctl	= video_ioctl2,
+};
+
+/*----------------------------------------------------------------------------*/
+/*
+ * The long list of v4l2 ioctl ops
+ */
+
+static int viacam_g_chip_ident(struct file *file, void *priv,
+		struct v4l2_dbg_chip_ident *ident)
+{
+	struct via_camera *cam = priv;
+
+	ident->ident = V4L2_IDENT_NONE;
+	ident->revision = 0;
+	if (v4l2_chip_match_host(&ident->match)) {
+		ident->ident = V4L2_IDENT_VIA_VX855;
+		return 0;
+	}
+	return sensor_call(cam, core, g_chip_ident, ident);
+}
+
+/*
+ * Control ops are passed through to the sensor.
+ */
+static int viacam_queryctrl(struct file *filp, void *priv,
+		struct v4l2_queryctrl *qc)
+{
+	struct via_camera *cam = priv;
+	int ret;
+
+	mutex_lock(&cam->lock);
+	ret = sensor_call(cam, core, queryctrl, qc);
+	mutex_unlock(&cam->lock);
+	return ret;
+}
+
+
+static int viacam_g_ctrl(struct file *filp, void *priv,
+		struct v4l2_control *ctrl)
+{
+	struct via_camera *cam = priv;
+	int ret;
+
+	mutex_lock(&cam->lock);
+	ret = sensor_call(cam, core, g_ctrl, ctrl);
+	mutex_unlock(&cam->lock);
+	return ret;
+}
+
+
+static int viacam_s_ctrl(struct file *filp, void *priv,
+		struct v4l2_control *ctrl)
+{
+	struct via_camera *cam = priv;
+	int ret;
+
+	mutex_lock(&cam->lock);
+	ret = sensor_call(cam, core, s_ctrl, ctrl);
+	mutex_unlock(&cam->lock);
+	return ret;
+}
+
+/*
+ * Only one input.
+ */
+static int viacam_enum_input(struct file *filp, void *priv,
+		struct v4l2_input *input)
+{
+	if (input->index != 0)
+		return -EINVAL;
+
+	input->type = V4L2_INPUT_TYPE_CAMERA;
+	input->std = V4L2_STD_ALL; /* Not sure what should go here */
+	strcpy(input->name, "Camera");
+	return 0;
+}
+
+static int viacam_g_input(struct file *filp, void *priv, unsigned int *i)
+{
+	*i = 0;
+	return 0;
+}
+
+static int viacam_s_input(struct file *filp, void *priv, unsigned int i)
+{
+	if (i != 0)
+		return -EINVAL;
+	return 0;
+}
+
+static int viacam_s_std(struct file *filp, void *priv, v4l2_std_id *std)
+{
+	return 0;
+}
+
+/*
+ * Video format stuff.	Here is our default format until
+ * user space messes with things.
+ */
+static const struct v4l2_pix_format viacam_def_pix_format = {
+	.width		= VGA_WIDTH,
+	.height		= VGA_HEIGHT,
+	.pixelformat	= V4L2_PIX_FMT_YUYV,
+	.field		= V4L2_FIELD_NONE,
+	.bytesperline	= VGA_WIDTH * 2,
+	.sizeimage	= VGA_WIDTH * VGA_HEIGHT * 2,
+};
+
+static const enum v4l2_mbus_pixelcode via_def_mbus_code = V4L2_MBUS_FMT_YUYV8_2X8;
+
+static int viacam_enum_fmt_vid_cap(struct file *filp, void *priv,
+		struct v4l2_fmtdesc *fmt)
+{
+	if (fmt->index >= N_VIA_FMTS)
+		return -EINVAL;
+	strlcpy(fmt->description, via_formats[fmt->index].desc,
+			sizeof(fmt->description));
+	fmt->pixelformat = via_formats[fmt->index].pixelformat;
+	return 0;
+}
+
+/*
+ * Figure out proper image dimensions, but always force the
+ * sensor to VGA.
+ */
+static void viacam_fmt_pre(struct v4l2_pix_format *userfmt,
+		struct v4l2_pix_format *sensorfmt)
+{
+	*sensorfmt = *userfmt;
+	if (userfmt->width < QCIF_WIDTH || userfmt->height < QCIF_HEIGHT) {
+		userfmt->width = QCIF_WIDTH;
+		userfmt->height = QCIF_HEIGHT;
+	}
+	if (userfmt->width > VGA_WIDTH || userfmt->height > VGA_HEIGHT) {
+		userfmt->width = VGA_WIDTH;
+		userfmt->height = VGA_HEIGHT;
+	}
+	sensorfmt->width = VGA_WIDTH;
+	sensorfmt->height = VGA_HEIGHT;
+}
+
+static void viacam_fmt_post(struct v4l2_pix_format *userfmt,
+		struct v4l2_pix_format *sensorfmt)
+{
+	struct via_format *f = via_find_format(userfmt->pixelformat);
+
+	sensorfmt->bytesperline = sensorfmt->width * f->bpp;
+	sensorfmt->sizeimage = sensorfmt->height * sensorfmt->bytesperline;
+	userfmt->pixelformat = sensorfmt->pixelformat;
+	userfmt->field = sensorfmt->field;
+	userfmt->bytesperline = 2 * userfmt->width;
+	userfmt->sizeimage = userfmt->bytesperline * userfmt->height;
+}
+
+
+/*
+ * The real work of figuring out a workable format.
+ */
+static int viacam_do_try_fmt(struct via_camera *cam,
+		struct v4l2_pix_format *upix, struct v4l2_pix_format *spix)
+{
+	int ret;
+	struct v4l2_mbus_framefmt mbus_fmt;
+	struct via_format *f = via_find_format(upix->pixelformat);
+
+	upix->pixelformat = f->pixelformat;
+	viacam_fmt_pre(upix, spix);
+	v4l2_fill_mbus_format(&mbus_fmt, upix, f->mbus_code);
+	ret = sensor_call(cam, video, try_mbus_fmt, &mbus_fmt);
+	v4l2_fill_pix_format(spix, &mbus_fmt);
+	viacam_fmt_post(upix, spix);
+	return ret;
+}
+
+
+
+static int viacam_try_fmt_vid_cap(struct file *filp, void *priv,
+		struct v4l2_format *fmt)
+{
+	struct via_camera *cam = priv;
+	struct v4l2_format sfmt;
+	int ret;
+
+	mutex_lock(&cam->lock);
+	ret = viacam_do_try_fmt(cam, &fmt->fmt.pix, &sfmt.fmt.pix);
+	mutex_unlock(&cam->lock);
+	return ret;
+}
+
+
+static int viacam_g_fmt_vid_cap(struct file *filp, void *priv,
+		struct v4l2_format *fmt)
+{
+	struct via_camera *cam = priv;
+
+	mutex_lock(&cam->lock);
+	fmt->fmt.pix = cam->user_format;
+	mutex_unlock(&cam->lock);
+	return 0;
+}
+
+static int viacam_s_fmt_vid_cap(struct file *filp, void *priv,
+		struct v4l2_format *fmt)
+{
+	struct via_camera *cam = priv;
+	int ret;
+	struct v4l2_format sfmt;
+	struct via_format *f = via_find_format(fmt->fmt.pix.pixelformat);
+
+	/*
+	 * Camera must be idle or we can't mess with the
+	 * video setup.
+	 */
+	mutex_lock(&cam->lock);
+	if (cam->opstate != S_IDLE) {
+		ret = -EBUSY;
+		goto out;
+	}
+	/*
+	 * Let the sensor code look over and tweak the
+	 * requested formatting.
+	 */
+	ret = viacam_do_try_fmt(cam, &fmt->fmt.pix, &sfmt.fmt.pix);
+	if (ret)
+		goto out;
+	/*
+	 * OK, let's commit to the new format.
+	 */
+	cam->user_format = fmt->fmt.pix;
+	cam->sensor_format = sfmt.fmt.pix;
+	cam->mbus_code = f->mbus_code;
+	ret = viacam_configure_sensor(cam);
+	if (!ret)
+		ret = viacam_config_controller(cam);
+out:
+	mutex_unlock(&cam->lock);
+	return ret;
+}
+
+static int viacam_querycap(struct file *filp, void *priv,
+		struct v4l2_capability *cap)
+{
+	strcpy(cap->driver, "via-camera");
+	strcpy(cap->card, "via-camera");
+	cap->version = 1;
+	cap->capabilities = V4L2_CAP_VIDEO_CAPTURE |
+		V4L2_CAP_READWRITE | V4L2_CAP_STREAMING;
+	return 0;
+}
+
+/*
+ * Streaming operations - pure videobuf stuff.
+ */
+static int viacam_reqbufs(struct file *filp, void *priv,
+		struct v4l2_requestbuffers *rb)
+{
+	struct via_camera *cam = priv;
+
+	return videobuf_reqbufs(&cam->vb_queue, rb);
+}
+
+static int viacam_querybuf(struct file *filp, void *priv,
+		struct v4l2_buffer *buf)
+{
+	struct via_camera *cam = priv;
+
+	return videobuf_querybuf(&cam->vb_queue, buf);
+}
+
+static int viacam_qbuf(struct file *filp, void *priv, struct v4l2_buffer *buf)
+{
+	struct via_camera *cam = priv;
+
+	return videobuf_qbuf(&cam->vb_queue, buf);
+}
+
+static int viacam_dqbuf(struct file *filp, void *priv, struct v4l2_buffer *buf)
+{
+	struct via_camera *cam = priv;
+
+	return videobuf_dqbuf(&cam->vb_queue, buf, filp->f_flags & O_NONBLOCK);
+}
+
+static int viacam_streamon(struct file *filp, void *priv, enum v4l2_buf_type t)
+{
+	struct via_camera *cam = priv;
+	int ret = 0;
+
+	if (t != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+
+	mutex_lock(&cam->lock);
+	if (cam->opstate != S_IDLE) {
+		ret = -EBUSY;
+		goto out;
+	}
+	/*
+	 * Enforce the V4l2 "only one owner gets to read data" rule.
+	 */
+	if (cam->owner && cam->owner != filp) {
+		ret = -EBUSY;
+		goto out;
+	}
+	cam->owner = filp;
+	/*
+	 * Configure things if need be.
+	 */
+	if (test_bit(CF_CONFIG_NEEDED, &cam->flags)) {
+		ret = viacam_configure_sensor(cam);
+		if (ret)
+			goto out;
+		ret = viacam_config_controller(cam);
+		if (ret)
+			goto out;
+	}
+	/*
+	 * If the CPU goes into C3, the DMA transfer gets corrupted and
+	 * users start filing unsightly bug reports.  Put in a "latency"
+	 * requirement which will keep the CPU out of the deeper sleep
+	 * states.
+	 */
+	pm_qos_add_request(&cam->qos_request, PM_QOS_CPU_DMA_LATENCY, 50);
+	/*
+	 * Fire things up.
+	 */
+	INIT_LIST_HEAD(&cam->buffer_queue);
+	ret = videobuf_streamon(&cam->vb_queue);
+	if (!ret)
+		viacam_start_engine(cam);
+out:
+	mutex_unlock(&cam->lock);
+	return ret;
+}
+
+static int viacam_streamoff(struct file *filp, void *priv, enum v4l2_buf_type t)
+{
+	struct via_camera *cam = priv;
+	int ret;
+
+	if (t != V4L2_BUF_TYPE_VIDEO_CAPTURE)
+		return -EINVAL;
+	mutex_lock(&cam->lock);
+	if (cam->opstate != S_RUNNING) {
+		ret = -EINVAL;
+		goto out;
+	}
+	pm_qos_remove_request(&cam->qos_request);
+	viacam_stop_engine(cam);
+	/*
+	 * Videobuf will recycle all of the outstanding buffers, but
+	 * we should be sure we don't retain any references to
+	 * any of them.
+	 */
+	ret = videobuf_streamoff(&cam->vb_queue);
+	INIT_LIST_HEAD(&cam->buffer_queue);
+out:
+	mutex_unlock(&cam->lock);
+	return ret;
+}
+
+#ifdef CONFIG_VIDEO_V4L1_COMPAT
+static int viacam_vidiocgmbuf(struct file *filp, void *priv,
+		struct video_mbuf *mbuf)
+{
+	struct via_camera *cam = priv;
+
+	return videobuf_cgmbuf(&cam->vb_queue, mbuf, 6);
+}
+#endif
+
+/* G/S_PARM */
+
+static int viacam_g_parm(struct file *filp, void *priv,
+		struct v4l2_streamparm *parm)
+{
+	struct via_camera *cam = priv;
+	int ret;
+
+	mutex_lock(&cam->lock);
+	ret = sensor_call(cam, video, g_parm, parm);
+	mutex_unlock(&cam->lock);
+	parm->parm.capture.readbuffers = cam->n_cap_bufs;
+	return ret;
+}
+
+static int viacam_s_parm(struct file *filp, void *priv,
+		struct v4l2_streamparm *parm)
+{
+	struct via_camera *cam = priv;
+	int ret;
+
+	mutex_lock(&cam->lock);
+	ret = sensor_call(cam, video, s_parm, parm);
+	mutex_unlock(&cam->lock);
+	parm->parm.capture.readbuffers = cam->n_cap_bufs;
+	return ret;
+}
+
+static int viacam_enum_framesizes(struct file *filp, void *priv,
+		struct v4l2_frmsizeenum *sizes)
+{
+	if (sizes->index != 0)
+		return -EINVAL;
+	sizes->type = V4L2_FRMSIZE_TYPE_CONTINUOUS;
+	sizes->stepwise.min_width = QCIF_WIDTH;
+	sizes->stepwise.min_height = QCIF_HEIGHT;
+	sizes->stepwise.max_width = VGA_WIDTH;
+	sizes->stepwise.max_height = VGA_HEIGHT;
+	sizes->stepwise.step_width = sizes->stepwise.step_height = 1;
+	return 0;
+}
+
+static int viacam_enum_frameintervals(struct file *filp, void *priv,
+		struct v4l2_frmivalenum *interval)
+{
+	struct via_camera *cam = priv;
+	int ret;
+
+	mutex_lock(&cam->lock);
+	ret = sensor_call(cam, video, enum_frameintervals, interval);
+	mutex_unlock(&cam->lock);
+	return ret;
+}
+
+
+
+static const struct v4l2_ioctl_ops viacam_ioctl_ops = {
+	.vidioc_g_chip_ident	= viacam_g_chip_ident,
+	.vidioc_queryctrl	= viacam_queryctrl,
+	.vidioc_g_ctrl		= viacam_g_ctrl,
+	.vidioc_s_ctrl		= viacam_s_ctrl,
+	.vidioc_enum_input	= viacam_enum_input,
+	.vidioc_g_input		= viacam_g_input,
+	.vidioc_s_input		= viacam_s_input,
+	.vidioc_s_std		= viacam_s_std,
+	.vidioc_enum_fmt_vid_cap = viacam_enum_fmt_vid_cap,
+	.vidioc_try_fmt_vid_cap = viacam_try_fmt_vid_cap,
+	.vidioc_g_fmt_vid_cap	= viacam_g_fmt_vid_cap,
+	.vidioc_s_fmt_vid_cap	= viacam_s_fmt_vid_cap,
+	.vidioc_querycap	= viacam_querycap,
+	.vidioc_reqbufs		= viacam_reqbufs,
+	.vidioc_querybuf	= viacam_querybuf,
+	.vidioc_qbuf		= viacam_qbuf,
+	.vidioc_dqbuf		= viacam_dqbuf,
+	.vidioc_streamon	= viacam_streamon,
+	.vidioc_streamoff	= viacam_streamoff,
+	.vidioc_g_parm		= viacam_g_parm,
+	.vidioc_s_parm		= viacam_s_parm,
+	.vidioc_enum_framesizes = viacam_enum_framesizes,
+	.vidioc_enum_frameintervals = viacam_enum_frameintervals,
+#ifdef CONFIG_VIDEO_V4L1_COMPAT
+	.vidiocgmbuf		= viacam_vidiocgmbuf,
+#endif
+};
+
+/*----------------------------------------------------------------------------*/
+
+/*
+ * Power management.
+ */
+
+/*
+ * Setup stuff.
+ */
+
+static struct video_device viacam_v4l_template = {
+	.name		= "via-camera",
+	.minor		= -1,
+	.tvnorms	= V4L2_STD_NTSC_M,
+	.current_norm	= V4L2_STD_NTSC_M,
+	.fops		= &viacam_fops,
+	.ioctl_ops	= &viacam_ioctl_ops,
+	.release	= video_device_release_empty, /* Check this */
+};
+
+
+static __devinit int viacam_probe(struct platform_device *pdev)
+{
+	int ret;
+	struct i2c_adapter *sensor_adapter;
+	struct viafb_dev *viadev = pdev->dev.platform_data;
+
+	/*
+	 * Note that there are actually two capture channels on
+	 * the device.	We only deal with one for now.	That
+	 * is encoded here; nothing else assumes it's dealing with
+	 * a unique capture device.
+	 */
+	struct via_camera *cam;
+
+	/*
+	 * Ensure that frame buffer memory has been set aside for
+	 * this purpose.  As an arbitrary limit, refuse to work
+	 * with less than two frames of VGA 16-bit data.
+	 *
+	 * If we ever support the second port, we'll need to set
+	 * aside more memory.
+	 */
+	if (viadev->camera_fbmem_size < (VGA_HEIGHT*VGA_WIDTH*4)) {
+		printk(KERN_ERR "viacam: insufficient FB memory reserved\n");
+		return -ENOMEM;
+	}
+	if (viadev->engine_mmio == NULL) {
+		printk(KERN_ERR "viacam: No I/O memory, so no pictures\n");
+		return -ENOMEM;
+	}
+	/*
+	 * Basic structure initialization.
+	 */
+	cam = kzalloc (sizeof(struct via_camera), GFP_KERNEL);
+	if (cam == NULL)
+		return -ENOMEM;
+	via_cam_info = cam;
+	cam->platdev = pdev;
+	cam->viadev = viadev;
+	cam->users = 0;
+	cam->owner = NULL;
+	cam->opstate = S_IDLE;
+	cam->user_format = cam->sensor_format = viacam_def_pix_format;
+	mutex_init(&cam->lock);
+	INIT_LIST_HEAD(&cam->buffer_queue);
+	cam->mmio = viadev->engine_mmio;
+	cam->fbmem = viadev->fbmem;
+	cam->fb_offset = viadev->camera_fbmem_offset;
+	cam->flags = 1 << CF_CONFIG_NEEDED;
+	cam->mbus_code = via_def_mbus_code;
+	/*
+	 * Tell V4L that we exist.
+	 */
+	ret = v4l2_device_register(&pdev->dev, &cam->v4l2_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to register v4l2 device\n");
+		return ret;
+	}
+	/*
+	 * Convince the system that we can do DMA.
+	 */
+	pdev->dev.dma_mask = &viadev->pdev->dma_mask;
+	dma_set_mask(&pdev->dev, 0xffffffff);
+	/*
+	 * Fire up the capture port.  The write to 0x78 looks purely
+	 * OLPCish; any system will need to tweak 0x1e.
+	 */
+	via_write_reg_mask(VIASR, 0x78, 0, 0x80);
+	via_write_reg_mask(VIASR, 0x1e, 0xc0, 0xc0);
+	/*
+	 * Get the sensor powered up.
+	 */
+	ret = via_sensor_power_setup(cam);
+	if (ret)
+		goto out_unregister;
+	via_sensor_power_up(cam);
+
+	/*
+	 * See if we can't find it on the bus.	The VIA_PORT_31 assumption
+	 * is OLPC-specific.  0x42 assumption is ov7670-specific.
+	 */
+	sensor_adapter = viafb_find_i2c_adapter(VIA_PORT_31);
+	cam->sensor = v4l2_i2c_new_subdev(&cam->v4l2_dev, sensor_adapter,
+			"ov7670", "ov7670", 0x42 >> 1, NULL);
+	if (cam->sensor == NULL) {
+		dev_err(&pdev->dev, "Unable to find the sensor!\n");
+		ret = -ENODEV;
+		goto out_power_down;
+	}
+	/*
+	 * Get the IRQ.
+	 */
+	viacam_int_disable(cam);
+	ret = request_threaded_irq(viadev->pdev->irq, viacam_quick_irq,
+			viacam_irq, IRQF_SHARED, "via-camera", cam);
+	if (ret)
+		goto out_power_down;
+	/*
+	 * Tell V4l2 that we exist.
+	 */
+	cam->vdev = viacam_v4l_template;
+	cam->vdev.v4l2_dev = &cam->v4l2_dev;
+	ret = video_register_device(&cam->vdev, VFL_TYPE_GRABBER, -1);
+	if (ret)
+		goto out_irq;
+	video_set_drvdata(&cam->vdev, cam);
+
+	/* Power the sensor down until somebody opens the device */
+	via_sensor_power_down(cam);
+	return 0;
+
+out_irq:
+	free_irq(viadev->pdev->irq, cam);
+out_power_down:
+	via_sensor_power_release(cam);
+out_unregister:
+	v4l2_device_unregister(&cam->v4l2_dev);
+	return ret;
+}
+
+static __devexit int viacam_remove(struct platform_device *pdev)
+{
+	struct via_camera *cam = via_cam_info;
+	struct viafb_dev *viadev = pdev->dev.platform_data;
+
+	video_unregister_device(&cam->vdev);
+	v4l2_device_unregister(&cam->v4l2_dev);
+	free_irq(viadev->pdev->irq, cam);
+	via_sensor_power_release(cam);
+	via_cam_info = NULL;
+	return 0;
+}
+
+
+static struct platform_driver viacam_driver = {
+	.driver = {
+		.name = "viafb-camera",
+	},
+	.probe = viacam_probe,
+	.remove = viacam_remove,
+};
+
+
+#ifdef CONFIG_OLPC_XO_1_5
+/*
+ * The OLPC folks put the serial port on the same pin as
+ * the camera.	They also get grumpy if we break the
+ * serial port and keep them from using it.  So we have
+ * to check the serial enable bit and not step on it.
+ */
+#define VIACAM_SERIAL_DEVFN 0x88
+#define VIACAM_SERIAL_CREG 0x46
+#define VIACAM_SERIAL_BIT 0x40
+
+static __devinit int viacam_check_serial_port(void)
+{
+	struct pci_bus *pbus = pci_find_bus(0, 0);
+	u8 cbyte;
+
+	pci_bus_read_config_byte(pbus, VIACAM_SERIAL_DEVFN,
+			VIACAM_SERIAL_CREG, &cbyte);
+	if ((cbyte & VIACAM_SERIAL_BIT) == 0)
+		return 0; /* Not enabled */
+	if (override_serial == 0) {
+		printk(KERN_NOTICE "Via camera: serial port is enabled, " \
+				"refusing to load.\n");
+		printk(KERN_NOTICE "Specify override_serial=1 to force " \
+				"module loading.\n");
+		return -EBUSY;
+	}
+	printk(KERN_NOTICE "Via camera: overriding serial port\n");
+	pci_bus_write_config_byte(pbus, VIACAM_SERIAL_DEVFN,
+			VIACAM_SERIAL_CREG, cbyte & ~VIACAM_SERIAL_BIT);
+	return 0;
+}
+#endif
+
+
+
+
+static int viacam_init(void)
+{
+#ifdef CONFIG_OLPC_XO_1_5
+	if (viacam_check_serial_port())
+		return -EBUSY;
+#endif
+	return platform_driver_register(&viacam_driver);
+}
+module_init(viacam_init);
+
+static void viacam_exit(void)
+{
+	platform_driver_unregister(&viacam_driver);
+}
+module_exit(viacam_exit);
diff --git a/drivers/media/video/via-camera.h b/drivers/media/video/via-camera.h
new file mode 100644
index 000000000000..b12a4b3d616f
--- /dev/null
+++ b/drivers/media/video/via-camera.h
@@ -0,0 +1,93 @@
+/*
+ * VIA Camera register definitions.
+ */
+#define VCR_INTCTRL	0x300	/* Capture interrupt control */
+#define   VCR_IC_EAV	  0x0001   /* End of active video status */
+#define	  VCR_IC_EVBI	  0x0002   /* End of VBI status */
+#define   VCR_IC_FBOTFLD  0x0004   /* "flipping" Bottom field is active */
+#define   VCR_IC_ACTBUF	  0x0018   /* Active video buffer  */
+#define   VCR_IC_VSYNC	  0x0020   /* 0 = VB, 1 = active video */
+#define   VCR_IC_BOTFLD	  0x0040   /* Bottom field is active */
+#define   VCR_IC_FFULL	  0x0080   /* FIFO full */
+#define   VCR_IC_INTEN	  0x0100   /* End of active video int. enable */
+#define   VCR_IC_VBIINT	  0x0200   /* End of VBI int enable */
+#define   VCR_IC_VBIBUF	  0x0400   /* Current VBI buffer */
+
+#define VCR_TSC		0x308	/* Transport stream control */
+#define VCR_TSC_ENABLE    0x000001   /* Transport stream input enable */
+#define VCR_TSC_DROPERR   0x000002   /* Drop error packets */
+#define VCR_TSC_METHOD    0x00000c   /* DMA method (non-functional) */
+#define VCR_TSC_COUNT     0x07fff0   /* KByte or packet count */
+#define VCR_TSC_CBMODE	  0x080000   /* Change buffer by byte count */
+#define VCR_TSC_PSSIG	  0x100000   /* Packet starting signal disable */
+#define VCR_TSC_BE	  0x200000   /* MSB first (serial mode) */
+#define VCR_TSC_SERIAL	  0x400000   /* Serial input (0 = parallel) */
+
+#define VCR_CAPINTC	0x310	/* Capture interface control */
+#define   VCR_CI_ENABLE   0x00000001  /* Capture enable */
+#define   VCR_CI_BSS	  0x00000002  /* WTF "bit stream selection" */
+#define   VCR_CI_3BUFS	  0x00000004  /* 1 = 3 buffers, 0 = 2 buffers */
+#define   VCR_CI_VIPEN	  0x00000008  /* VIP enable */
+#define   VCR_CI_CCIR601_8  0	        /* CCIR601 input stream, 8 bit */
+#define   VCR_CI_CCIR656_8  0x00000010  /* ... CCIR656, 8 bit */
+#define   VCR_CI_CCIR601_16 0x00000020  /* ... CCIR601, 16 bit */
+#define   VCR_CI_CCIR656_16 0x00000030  /* ... CCIR656, 16 bit */
+#define   VCR_CI_HDMODE   0x00000040  /* CCIR656-16 hdr decode mode; 1=16b */
+#define   VCR_CI_BSWAP    0x00000080  /* Swap bytes (16-bit) */
+#define   VCR_CI_YUYV	  0	      /* Byte order 0123 */
+#define   VCR_CI_UYVY	  0x00000100  /* Byte order 1032 */
+#define   VCR_CI_YVYU	  0x00000200  /* Byte order 0321 */
+#define   VCR_CI_VYUY	  0x00000300  /* Byte order 3012 */
+#define   VCR_CI_VIPTYPE  0x00000400  /* VIP type */
+#define   VCR_CI_IFSEN    0x00000800  /* Input field signal enable */
+#define   VCR_CI_DIODD	  0	      /* De-interlace odd, 30fps */
+#define   VCR_CI_DIEVEN   0x00001000  /*    ...even field, 30fps */
+#define   VCR_CI_DIBOTH   0x00002000  /*    ...both fields, 60fps */
+#define   VCR_CI_DIBOTH30 0x00003000  /*    ...both fields, 30fps interlace */
+#define   VCR_CI_CONVTYPE 0x00004000  /* 4:2:2 to 4:4:4; 1 = interpolate */
+#define   VCR_CI_CFC	  0x00008000  /* Capture flipping control */
+#define   VCR_CI_FILTER   0x00070000  /* Horiz filter mode select
+					 000 = none
+					 001 = 2 tap
+					 010 = 3 tap
+					 011 = 4 tap
+					 100 = 5 tap */
+#define   VCR_CI_CLKINV   0x00080000  /* Input CLK inverted */
+#define   VCR_CI_VREFINV  0x00100000  /* VREF inverted */
+#define   VCR_CI_HREFINV  0x00200000  /* HREF inverted */
+#define   VCR_CI_FLDINV   0x00400000  /* Field inverted */
+#define   VCR_CI_CLKPIN	  0x00800000  /* Capture clock pin */
+#define   VCR_CI_THRESH   0x0f000000  /* Capture fifo threshold */
+#define   VCR_CI_HRLE     0x10000000  /* Positive edge of HREF */
+#define   VCR_CI_VRLE     0x20000000  /* Positive edge of VREF */
+#define   VCR_CI_OFLDINV  0x40000000  /* Field output inverted */
+#define   VCR_CI_CLKEN    0x80000000  /* Capture clock enable */
+
+#define VCR_HORRANGE	0x314	/* Active video horizontal range */
+#define VCR_VERTRANGE	0x318	/* Active video vertical range */
+#define VCR_AVSCALE	0x31c	/* Active video scaling control */
+#define   VCR_AVS_HEN	  0x00000800   /* Horizontal scale enable */
+#define   VCR_AVS_VEN	  0x04000000   /* Vertical enable */
+#define VCR_VBIHOR	0x320	/* VBI Data horizontal range */
+#define VCR_VBIVERT	0x324	/* VBI data vertical range */
+#define VCR_VBIBUF1	0x328	/* First VBI buffer */
+#define VCR_VBISTRIDE	0x32c	/* VBI stride */
+#define VCR_ANCDATACNT	0x330	/* Ancillary data count setting */
+#define VCR_MAXDATA	0x334	/* Active data count of active video */
+#define VCR_MAXVBI	0x338	/* Maximum data count of VBI */
+#define VCR_CAPDATA	0x33c	/* Capture data count */
+#define VCR_VBUF1	0x340	/* First video buffer */
+#define VCR_VBUF2	0x344	/* Second video buffer */
+#define VCR_VBUF3	0x348	/* Third video buffer */
+#define VCR_VBUF_MASK	0x1ffffff0	/* Bits 28:4 */
+#define VCR_VBIBUF2	0x34c	/* Second VBI buffer */
+#define VCR_VSTRIDE	0x350	/* Stride of video + coring control */
+#define   VCR_VS_STRIDE_SHIFT 4
+#define   VCR_VS_STRIDE   0x00001ff0  /* Stride (8-byte units) */
+#define   VCR_VS_CCD	  0x007f0000  /* Coring compare data */
+#define   VCR_VS_COREEN   0x00800000  /* Coring enable */
+#define VCR_TS0ERR	0x354	/* TS buffer 0 error indicator */
+#define VCR_TS1ERR	0x358	/* TS buffer 0 error indicator */
+#define VCR_TS2ERR	0x35c	/* TS buffer 0 error indicator */
+
+/* Add 0x1000 for the second capture engine registers */