Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 580 insertions, 0 deletions

diff --git a/drivers/media/usb/gspca/w996Xcf.c b/drivers/media/usb/gspca/w996Xcf.c
new file mode 100644
index 000000000..ef0a839f9
--- /dev/null
+++ b/drivers/media/usb/gspca/w996Xcf.c
@@ -0,0 +1,580 @@
+/**
+ *
+ * GSPCA sub driver for W996[78]CF JPEG USB Dual Mode Camera Chip.
+ *
+ * Copyright (C) 2009 Hans de Goede <hdegoede@redhat.com>
+ *
+ * This module is adapted from the in kernel v4l1 w9968cf driver:
+ *
+ * Copyright (C) 2002-2004 by Luca Risolia <luca.risolia@studio.unibo.it>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+/* Note this is not a stand alone driver, it gets included in ov519.c, this
+   is a bit of a hack, but it needs the driver code for a lot of different
+   ov sensors which is already present in ov519.c (the old v4l1 driver used
+   the ovchipcam framework). When we have the time we really should move
+   the sensor drivers to v4l2 sub drivers, and properly split of this
+   driver from ov519.c */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define W9968CF_I2C_BUS_DELAY    4 /* delay in us for I2C bit r/w operations */
+
+#define Y_QUANTABLE (&sd->jpeg_hdr[JPEG_QT0_OFFSET])
+#define UV_QUANTABLE (&sd->jpeg_hdr[JPEG_QT1_OFFSET])
+
+static const struct v4l2_pix_format w9968cf_vga_mode[] = {
+	{160, 120, V4L2_PIX_FMT_UYVY, V4L2_FIELD_NONE,
+		.bytesperline = 160 * 2,
+		.sizeimage = 160 * 120 * 2,
+		.colorspace = V4L2_COLORSPACE_JPEG},
+	{176, 144, V4L2_PIX_FMT_UYVY, V4L2_FIELD_NONE,
+		.bytesperline = 176 * 2,
+		.sizeimage = 176 * 144 * 2,
+		.colorspace = V4L2_COLORSPACE_JPEG},
+	{320, 240, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
+		.bytesperline = 320 * 2,
+		.sizeimage = 320 * 240 * 2,
+		.colorspace = V4L2_COLORSPACE_JPEG},
+	{352, 288, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
+		.bytesperline = 352 * 2,
+		.sizeimage = 352 * 288 * 2,
+		.colorspace = V4L2_COLORSPACE_JPEG},
+	{640, 480, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
+		.bytesperline = 640 * 2,
+		.sizeimage = 640 * 480 * 2,
+		.colorspace = V4L2_COLORSPACE_JPEG},
+};
+
+static void reg_w(struct sd *sd, u16 index, u16 value);
+
+/*--------------------------------------------------------------------------
+  Write 64-bit data to the fast serial bus registers.
+  Return 0 on success, -1 otherwise.
+  --------------------------------------------------------------------------*/
+static void w9968cf_write_fsb(struct sd *sd, u16* data)
+{
+	struct usb_device *udev = sd->gspca_dev.dev;
+	u16 value;
+	int ret;
+
+	if (sd->gspca_dev.usb_err < 0)
+		return;
+
+	value = *data++;
+	memcpy(sd->gspca_dev.usb_buf, data, 6);
+
+	/* Avoid things going to fast for the bridge with a xhci host */
+	udelay(150);
+	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0,
+			      USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE,
+			      value, 0x06, sd->gspca_dev.usb_buf, 6, 500);
+	if (ret < 0) {
+		pr_err("Write FSB registers failed (%d)\n", ret);
+		sd->gspca_dev.usb_err = ret;
+	}
+}
+
+/*--------------------------------------------------------------------------
+  Write data to the serial bus control register.
+  Return 0 on success, a negative number otherwise.
+  --------------------------------------------------------------------------*/
+static void w9968cf_write_sb(struct sd *sd, u16 value)
+{
+	int ret;
+
+	if (sd->gspca_dev.usb_err < 0)
+		return;
+
+	/* Avoid things going to fast for the bridge with a xhci host */
+	udelay(150);
+
+	/* We don't use reg_w here, as that would cause all writes when
+	   bitbanging i2c to be logged, making the logs impossible to read */
+	ret = usb_control_msg(sd->gspca_dev.dev,
+		usb_sndctrlpipe(sd->gspca_dev.dev, 0),
+		0,
+		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+		value, 0x01, NULL, 0, 500);
+
+	udelay(W9968CF_I2C_BUS_DELAY);
+
+	if (ret < 0) {
+		pr_err("Write SB reg [01] %04x failed\n", value);
+		sd->gspca_dev.usb_err = ret;
+	}
+}
+
+/*--------------------------------------------------------------------------
+  Read data from the serial bus control register.
+  Return 0 on success, a negative number otherwise.
+  --------------------------------------------------------------------------*/
+static int w9968cf_read_sb(struct sd *sd)
+{
+	int ret;
+
+	if (sd->gspca_dev.usb_err < 0)
+		return -1;
+
+	/* Avoid things going to fast for the bridge with a xhci host */
+	udelay(150);
+
+	/* We don't use reg_r here, as the w9968cf is special and has 16
+	   bit registers instead of 8 bit */
+	ret = usb_control_msg(sd->gspca_dev.dev,
+			usb_rcvctrlpipe(sd->gspca_dev.dev, 0),
+			1,
+			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+			0, 0x01, sd->gspca_dev.usb_buf, 2, 500);
+	if (ret >= 0) {
+		ret = sd->gspca_dev.usb_buf[0] |
+		      (sd->gspca_dev.usb_buf[1] << 8);
+	} else {
+		pr_err("Read SB reg [01] failed\n");
+		sd->gspca_dev.usb_err = ret;
+		/*
+		 * Make sure the buffer is zeroed to avoid uninitialized
+		 * values.
+		 */
+		memset(sd->gspca_dev.usb_buf, 0, 2);
+	}
+
+	udelay(W9968CF_I2C_BUS_DELAY);
+
+	return ret;
+}
+
+/*--------------------------------------------------------------------------
+  Upload quantization tables for the JPEG compression.
+  This function is called by w9968cf_start_transfer().
+  Return 0 on success, a negative number otherwise.
+  --------------------------------------------------------------------------*/
+static void w9968cf_upload_quantizationtables(struct sd *sd)
+{
+	u16 a, b;
+	int i, j;
+
+	reg_w(sd, 0x39, 0x0010); /* JPEG clock enable */
+
+	for (i = 0, j = 0; i < 32; i++, j += 2) {
+		a = Y_QUANTABLE[j] | ((unsigned)(Y_QUANTABLE[j + 1]) << 8);
+		b = UV_QUANTABLE[j] | ((unsigned)(UV_QUANTABLE[j + 1]) << 8);
+		reg_w(sd, 0x40 + i, a);
+		reg_w(sd, 0x60 + i, b);
+	}
+	reg_w(sd, 0x39, 0x0012); /* JPEG encoder enable */
+}
+
+/****************************************************************************
+ * Low-level I2C I/O functions.                                             *
+ * The adapter supports the following I2C transfer functions:               *
+ * i2c_adap_fastwrite_byte_data() (at 400 kHz bit frequency only)           *
+ * i2c_adap_read_byte_data()                                                *
+ * i2c_adap_read_byte()                                                     *
+ ****************************************************************************/
+
+static void w9968cf_smbus_start(struct sd *sd)
+{
+	w9968cf_write_sb(sd, 0x0011); /* SDE=1, SDA=0, SCL=1 */
+	w9968cf_write_sb(sd, 0x0010); /* SDE=1, SDA=0, SCL=0 */
+}
+
+static void w9968cf_smbus_stop(struct sd *sd)
+{
+	w9968cf_write_sb(sd, 0x0010); /* SDE=1, SDA=0, SCL=0 */
+	w9968cf_write_sb(sd, 0x0011); /* SDE=1, SDA=0, SCL=1 */
+	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
+}
+
+static void w9968cf_smbus_write_byte(struct sd *sd, u8 v)
+{
+	u8 bit;
+	int sda;
+
+	for (bit = 0 ; bit < 8 ; bit++) {
+		sda = (v & 0x80) ? 2 : 0;
+		v <<= 1;
+		/* SDE=1, SDA=sda, SCL=0 */
+		w9968cf_write_sb(sd, 0x10 | sda);
+		/* SDE=1, SDA=sda, SCL=1 */
+		w9968cf_write_sb(sd, 0x11 | sda);
+		/* SDE=1, SDA=sda, SCL=0 */
+		w9968cf_write_sb(sd, 0x10 | sda);
+	}
+}
+
+static void w9968cf_smbus_read_byte(struct sd *sd, u8 *v)
+{
+	u8 bit;
+
+	/* No need to ensure SDA is high as we are always called after
+	   read_ack which ends with SDA high */
+	*v = 0;
+	for (bit = 0 ; bit < 8 ; bit++) {
+		*v <<= 1;
+		/* SDE=1, SDA=1, SCL=1 */
+		w9968cf_write_sb(sd, 0x0013);
+		*v |= (w9968cf_read_sb(sd) & 0x0008) ? 1 : 0;
+		/* SDE=1, SDA=1, SCL=0 */
+		w9968cf_write_sb(sd, 0x0012);
+	}
+}
+
+static void w9968cf_smbus_write_nack(struct sd *sd)
+{
+	/* No need to ensure SDA is high as we are always called after
+	   read_byte which ends with SDA high */
+	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
+	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
+}
+
+static void w9968cf_smbus_read_ack(struct sd *sd)
+{
+	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
+	int sda;
+
+	/* Ensure SDA is high before raising clock to avoid a spurious stop */
+	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
+	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
+	sda = w9968cf_read_sb(sd);
+	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
+	if (sda >= 0 && (sda & 0x08)) {
+		gspca_dbg(gspca_dev, D_USBI, "Did not receive i2c ACK\n");
+		sd->gspca_dev.usb_err = -EIO;
+	}
+}
+
+/* SMBus protocol: S Addr Wr [A] Subaddr [A] Value [A] P */
+static void w9968cf_i2c_w(struct sd *sd, u8 reg, u8 value)
+{
+	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
+	u16* data = (u16 *)sd->gspca_dev.usb_buf;
+
+	data[0] = 0x082f | ((sd->sensor_addr & 0x80) ? 0x1500 : 0x0);
+	data[0] |= (sd->sensor_addr & 0x40) ? 0x4000 : 0x0;
+	data[1] = 0x2082 | ((sd->sensor_addr & 0x40) ? 0x0005 : 0x0);
+	data[1] |= (sd->sensor_addr & 0x20) ? 0x0150 : 0x0;
+	data[1] |= (sd->sensor_addr & 0x10) ? 0x5400 : 0x0;
+	data[2] = 0x8208 | ((sd->sensor_addr & 0x08) ? 0x0015 : 0x0);
+	data[2] |= (sd->sensor_addr & 0x04) ? 0x0540 : 0x0;
+	data[2] |= (sd->sensor_addr & 0x02) ? 0x5000 : 0x0;
+	data[3] = 0x1d20 | ((sd->sensor_addr & 0x02) ? 0x0001 : 0x0);
+	data[3] |= (sd->sensor_addr & 0x01) ? 0x0054 : 0x0;
+
+	w9968cf_write_fsb(sd, data);
+
+	data[0] = 0x8208 | ((reg & 0x80) ? 0x0015 : 0x0);
+	data[0] |= (reg & 0x40) ? 0x0540 : 0x0;
+	data[0] |= (reg & 0x20) ? 0x5000 : 0x0;
+	data[1] = 0x0820 | ((reg & 0x20) ? 0x0001 : 0x0);
+	data[1] |= (reg & 0x10) ? 0x0054 : 0x0;
+	data[1] |= (reg & 0x08) ? 0x1500 : 0x0;
+	data[1] |= (reg & 0x04) ? 0x4000 : 0x0;
+	data[2] = 0x2082 | ((reg & 0x04) ? 0x0005 : 0x0);
+	data[2] |= (reg & 0x02) ? 0x0150 : 0x0;
+	data[2] |= (reg & 0x01) ? 0x5400 : 0x0;
+	data[3] = 0x001d;
+
+	w9968cf_write_fsb(sd, data);
+
+	data[0] = 0x8208 | ((value & 0x80) ? 0x0015 : 0x0);
+	data[0] |= (value & 0x40) ? 0x0540 : 0x0;
+	data[0] |= (value & 0x20) ? 0x5000 : 0x0;
+	data[1] = 0x0820 | ((value & 0x20) ? 0x0001 : 0x0);
+	data[1] |= (value & 0x10) ? 0x0054 : 0x0;
+	data[1] |= (value & 0x08) ? 0x1500 : 0x0;
+	data[1] |= (value & 0x04) ? 0x4000 : 0x0;
+	data[2] = 0x2082 | ((value & 0x04) ? 0x0005 : 0x0);
+	data[2] |= (value & 0x02) ? 0x0150 : 0x0;
+	data[2] |= (value & 0x01) ? 0x5400 : 0x0;
+	data[3] = 0xfe1d;
+
+	w9968cf_write_fsb(sd, data);
+
+	gspca_dbg(gspca_dev, D_USBO, "i2c 0x%02x -> [0x%02x]\n", value, reg);
+}
+
+/* SMBus protocol: S Addr Wr [A] Subaddr [A] P S Addr+1 Rd [A] [Value] NA P */
+static int w9968cf_i2c_r(struct sd *sd, u8 reg)
+{
+	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
+	int ret = 0;
+	u8 value;
+
+	/* Fast serial bus data control disable */
+	w9968cf_write_sb(sd, 0x0013); /* don't change ! */
+
+	w9968cf_smbus_start(sd);
+	w9968cf_smbus_write_byte(sd, sd->sensor_addr);
+	w9968cf_smbus_read_ack(sd);
+	w9968cf_smbus_write_byte(sd, reg);
+	w9968cf_smbus_read_ack(sd);
+	w9968cf_smbus_stop(sd);
+	w9968cf_smbus_start(sd);
+	w9968cf_smbus_write_byte(sd, sd->sensor_addr + 1);
+	w9968cf_smbus_read_ack(sd);
+	w9968cf_smbus_read_byte(sd, &value);
+	/* signal we don't want to read anymore, the v4l1 driver used to
+	   send an ack here which is very wrong! (and then fixed
+	   the issues this gave by retrying reads) */
+	w9968cf_smbus_write_nack(sd);
+	w9968cf_smbus_stop(sd);
+
+	/* Fast serial bus data control re-enable */
+	w9968cf_write_sb(sd, 0x0030);
+
+	if (sd->gspca_dev.usb_err >= 0) {
+		ret = value;
+		gspca_dbg(gspca_dev, D_USBI, "i2c [0x%02X] -> 0x%02X\n",
+			  reg, value);
+	} else
+		gspca_err(gspca_dev, "i2c read [0x%02x] failed\n", reg);
+
+	return ret;
+}
+
+/*--------------------------------------------------------------------------
+  Turn on the LED on some webcams. A beep should be heard too.
+  Return 0 on success, a negative number otherwise.
+  --------------------------------------------------------------------------*/
+static void w9968cf_configure(struct sd *sd)
+{
+	reg_w(sd, 0x00, 0xff00); /* power-down */
+	reg_w(sd, 0x00, 0xbf17); /* reset everything */
+	reg_w(sd, 0x00, 0xbf10); /* normal operation */
+	reg_w(sd, 0x01, 0x0010); /* serial bus, SDS high */
+	reg_w(sd, 0x01, 0x0000); /* serial bus, SDS low */
+	reg_w(sd, 0x01, 0x0010); /* ..high 'beep-beep' */
+	reg_w(sd, 0x01, 0x0030); /* Set sda scl to FSB mode */
+
+	sd->stopped = 1;
+}
+
+static void w9968cf_init(struct sd *sd)
+{
+	unsigned long hw_bufsize = sd->sif ? (352 * 288 * 2) : (640 * 480 * 2),
+		      y0 = 0x0000,
+		      u0 = y0 + hw_bufsize / 2,
+		      v0 = u0 + hw_bufsize / 4,
+		      y1 = v0 + hw_bufsize / 4,
+		      u1 = y1 + hw_bufsize / 2,
+		      v1 = u1 + hw_bufsize / 4;
+
+	reg_w(sd, 0x00, 0xff00); /* power off */
+	reg_w(sd, 0x00, 0xbf10); /* power on */
+
+	reg_w(sd, 0x03, 0x405d); /* DRAM timings */
+	reg_w(sd, 0x04, 0x0030); /* SDRAM timings */
+
+	reg_w(sd, 0x20, y0 & 0xffff); /* Y buf.0, low */
+	reg_w(sd, 0x21, y0 >> 16);    /* Y buf.0, high */
+	reg_w(sd, 0x24, u0 & 0xffff); /* U buf.0, low */
+	reg_w(sd, 0x25, u0 >> 16);    /* U buf.0, high */
+	reg_w(sd, 0x28, v0 & 0xffff); /* V buf.0, low */
+	reg_w(sd, 0x29, v0 >> 16);    /* V buf.0, high */
+
+	reg_w(sd, 0x22, y1 & 0xffff); /* Y buf.1, low */
+	reg_w(sd, 0x23, y1 >> 16);    /* Y buf.1, high */
+	reg_w(sd, 0x26, u1 & 0xffff); /* U buf.1, low */
+	reg_w(sd, 0x27, u1 >> 16);    /* U buf.1, high */
+	reg_w(sd, 0x2a, v1 & 0xffff); /* V buf.1, low */
+	reg_w(sd, 0x2b, v1 >> 16);    /* V buf.1, high */
+
+	reg_w(sd, 0x32, y1 & 0xffff); /* JPEG buf 0 low */
+	reg_w(sd, 0x33, y1 >> 16);    /* JPEG buf 0 high */
+
+	reg_w(sd, 0x34, y1 & 0xffff); /* JPEG buf 1 low */
+	reg_w(sd, 0x35, y1 >> 16);    /* JPEG bug 1 high */
+
+	reg_w(sd, 0x36, 0x0000);/* JPEG restart interval */
+	reg_w(sd, 0x37, 0x0804);/*JPEG VLE FIFO threshold*/
+	reg_w(sd, 0x38, 0x0000);/* disable hw up-scaling */
+	reg_w(sd, 0x3f, 0x0000); /* JPEG/MCTL test data */
+}
+
+static void w9968cf_set_crop_window(struct sd *sd)
+{
+	int start_cropx, start_cropy,  x, y, fw, fh, cw, ch,
+	    max_width, max_height;
+
+	if (sd->sif) {
+		max_width  = 352;
+		max_height = 288;
+	} else {
+		max_width  = 640;
+		max_height = 480;
+	}
+
+	if (sd->sensor == SEN_OV7620) {
+		/*
+		 * Sigh, this is dependend on the clock / framerate changes
+		 * made by the frequency control, sick.
+		 *
+		 * Note we cannot use v4l2_ctrl_g_ctrl here, as we get called
+		 * from ov519.c:setfreq() with the ctrl lock held!
+		 */
+		if (sd->freq->val == 1) {
+			start_cropx = 277;
+			start_cropy = 37;
+		} else {
+			start_cropx = 105;
+			start_cropy = 37;
+		}
+	} else {
+		start_cropx = 320;
+		start_cropy = 35;
+	}
+
+	/* Work around to avoid FP arithmetics */
+	#define SC(x) ((x) << 10)
+
+	/* Scaling factors */
+	fw = SC(sd->gspca_dev.pixfmt.width) / max_width;
+	fh = SC(sd->gspca_dev.pixfmt.height) / max_height;
+
+	cw = (fw >= fh) ? max_width : SC(sd->gspca_dev.pixfmt.width) / fh;
+	ch = (fw >= fh) ? SC(sd->gspca_dev.pixfmt.height) / fw : max_height;
+
+	sd->sensor_width = max_width;
+	sd->sensor_height = max_height;
+
+	x = (max_width - cw) / 2;
+	y = (max_height - ch) / 2;
+
+	reg_w(sd, 0x10, start_cropx + x);
+	reg_w(sd, 0x11, start_cropy + y);
+	reg_w(sd, 0x12, start_cropx + x + cw);
+	reg_w(sd, 0x13, start_cropy + y + ch);
+}
+
+static void w9968cf_mode_init_regs(struct sd *sd)
+{
+	int val, vs_polarity, hs_polarity;
+
+	w9968cf_set_crop_window(sd);
+
+	reg_w(sd, 0x14, sd->gspca_dev.pixfmt.width);
+	reg_w(sd, 0x15, sd->gspca_dev.pixfmt.height);
+
+	/* JPEG width & height */
+	reg_w(sd, 0x30, sd->gspca_dev.pixfmt.width);
+	reg_w(sd, 0x31, sd->gspca_dev.pixfmt.height);
+
+	/* Y & UV frame buffer strides (in WORD) */
+	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
+	    V4L2_PIX_FMT_JPEG) {
+		reg_w(sd, 0x2c, sd->gspca_dev.pixfmt.width / 2);
+		reg_w(sd, 0x2d, sd->gspca_dev.pixfmt.width / 4);
+	} else
+		reg_w(sd, 0x2c, sd->gspca_dev.pixfmt.width);
+
+	reg_w(sd, 0x00, 0xbf17); /* reset everything */
+	reg_w(sd, 0x00, 0xbf10); /* normal operation */
+
+	/* Transfer size in WORDS (for UYVY format only) */
+	val = sd->gspca_dev.pixfmt.width * sd->gspca_dev.pixfmt.height;
+	reg_w(sd, 0x3d, val & 0xffff); /* low bits */
+	reg_w(sd, 0x3e, val >> 16);    /* high bits */
+
+	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
+	    V4L2_PIX_FMT_JPEG) {
+		/* We may get called multiple times (usb isoc bw negotiat.) */
+		jpeg_define(sd->jpeg_hdr, sd->gspca_dev.pixfmt.height,
+			    sd->gspca_dev.pixfmt.width, 0x22); /* JPEG 420 */
+		jpeg_set_qual(sd->jpeg_hdr, v4l2_ctrl_g_ctrl(sd->jpegqual));
+		w9968cf_upload_quantizationtables(sd);
+		v4l2_ctrl_grab(sd->jpegqual, true);
+	}
+
+	/* Video Capture Control Register */
+	if (sd->sensor == SEN_OV7620) {
+		/* Seems to work around a bug in the image sensor */
+		vs_polarity = 1;
+		hs_polarity = 1;
+	} else {
+		vs_polarity = 1;
+		hs_polarity = 0;
+	}
+
+	val = (vs_polarity << 12) | (hs_polarity << 11);
+
+	/* NOTE: We may not have enough memory to do double buffering while
+	   doing compression (amount of memory differs per model cam).
+	   So we use the second image buffer also as jpeg stream buffer
+	   (see w9968cf_init), and disable double buffering. */
+	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
+	    V4L2_PIX_FMT_JPEG) {
+		/* val |= 0x0002; YUV422P */
+		val |= 0x0003; /* YUV420P */
+	} else
+		val |= 0x0080; /* Enable HW double buffering */
+
+	/* val |= 0x0020; enable clamping */
+	/* val |= 0x0008; enable (1-2-1) filter */
+	/* val |= 0x000c; enable (2-3-6-3-2) filter */
+
+	val |= 0x8000; /* capt. enable */
+
+	reg_w(sd, 0x16, val);
+
+	sd->gspca_dev.empty_packet = 0;
+}
+
+static void w9968cf_stop0(struct sd *sd)
+{
+	v4l2_ctrl_grab(sd->jpegqual, false);
+	reg_w(sd, 0x39, 0x0000); /* disable JPEG encoder */
+	reg_w(sd, 0x16, 0x0000); /* stop video capture */
+}
+
+/* The w9968cf docs say that a 0 sized packet means EOF (and also SOF
+   for the next frame). This seems to simply not be true when operating
+   in JPEG mode, in this case there may be empty packets within the
+   frame. So in JPEG mode use the JPEG SOI marker to detect SOF.
+
+   Note to make things even more interesting the w9968cf sends *PLANAR* jpeg,
+   to be precise it sends: SOI, SOF, DRI, SOS, Y-data, SOS, U-data, SOS,
+   V-data, EOI. */
+static void w9968cf_pkt_scan(struct gspca_dev *gspca_dev,
+			u8 *data,			/* isoc packet */
+			int len)			/* iso packet length */
+{
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	if (w9968cf_vga_mode[gspca_dev->curr_mode].pixelformat ==
+	    V4L2_PIX_FMT_JPEG) {
+		if (len >= 2 &&
+		    data[0] == 0xff &&
+		    data[1] == 0xd8) {
+			gspca_frame_add(gspca_dev, LAST_PACKET,
+					NULL, 0);
+			gspca_frame_add(gspca_dev, FIRST_PACKET,
+					sd->jpeg_hdr, JPEG_HDR_SZ);
+			/* Strip the ff d8, our own header (which adds
+			   huffman and quantization tables) already has this */
+			len -= 2;
+			data += 2;
+		}
+	} else {
+		/* In UYVY mode an empty packet signals EOF */
+		if (gspca_dev->empty_packet) {
+			gspca_frame_add(gspca_dev, LAST_PACKET,
+						NULL, 0);
+			gspca_frame_add(gspca_dev, FIRST_PACKET,
+					NULL, 0);
+			gspca_dev->empty_packet = 0;
+		}
+	}
+	gspca_frame_add(gspca_dev, INTER_PACKET, data, len);
+}