xref: /openbmc/linux/drivers/media/usb/gspca/w996Xcf.c (revision bc5aa3a0)
1 /**
2  *
3  * GSPCA sub driver for W996[78]CF JPEG USB Dual Mode Camera Chip.
4  *
5  * Copyright (C) 2009 Hans de Goede <hdegoede@redhat.com>
6  *
7  * This module is adapted from the in kernel v4l1 w9968cf driver:
8  *
9  * Copyright (C) 2002-2004 by Luca Risolia <luca.risolia@studio.unibo.it>
10  *
11  * This program is free software; you can redistribute it and/or modify
12  * it under the terms of the GNU General Public License as published by
13  * the Free Software Foundation; either version 2 of the License, or
14  * any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License
22  * along with this program; if not, write to the Free Software
23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24  *
25  */
26 
27 /* Note this is not a stand alone driver, it gets included in ov519.c, this
28    is a bit of a hack, but it needs the driver code for a lot of different
29    ov sensors which is already present in ov519.c (the old v4l1 driver used
30    the ovchipcam framework). When we have the time we really should move
31    the sensor drivers to v4l2 sub drivers, and properly split of this
32    driver from ov519.c */
33 
34 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
35 
36 #define W9968CF_I2C_BUS_DELAY    4 /* delay in us for I2C bit r/w operations */
37 
38 #define Y_QUANTABLE (&sd->jpeg_hdr[JPEG_QT0_OFFSET])
39 #define UV_QUANTABLE (&sd->jpeg_hdr[JPEG_QT1_OFFSET])
40 
41 static const struct v4l2_pix_format w9968cf_vga_mode[] = {
42 	{160, 120, V4L2_PIX_FMT_UYVY, V4L2_FIELD_NONE,
43 		.bytesperline = 160 * 2,
44 		.sizeimage = 160 * 120 * 2,
45 		.colorspace = V4L2_COLORSPACE_JPEG},
46 	{176, 144, V4L2_PIX_FMT_UYVY, V4L2_FIELD_NONE,
47 		.bytesperline = 176 * 2,
48 		.sizeimage = 176 * 144 * 2,
49 		.colorspace = V4L2_COLORSPACE_JPEG},
50 	{320, 240, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
51 		.bytesperline = 320 * 2,
52 		.sizeimage = 320 * 240 * 2,
53 		.colorspace = V4L2_COLORSPACE_JPEG},
54 	{352, 288, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
55 		.bytesperline = 352 * 2,
56 		.sizeimage = 352 * 288 * 2,
57 		.colorspace = V4L2_COLORSPACE_JPEG},
58 	{640, 480, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
59 		.bytesperline = 640 * 2,
60 		.sizeimage = 640 * 480 * 2,
61 		.colorspace = V4L2_COLORSPACE_JPEG},
62 };
63 
64 static void reg_w(struct sd *sd, u16 index, u16 value);
65 
66 /*--------------------------------------------------------------------------
67   Write 64-bit data to the fast serial bus registers.
68   Return 0 on success, -1 otherwise.
69   --------------------------------------------------------------------------*/
70 static void w9968cf_write_fsb(struct sd *sd, u16* data)
71 {
72 	struct usb_device *udev = sd->gspca_dev.dev;
73 	u16 value;
74 	int ret;
75 
76 	if (sd->gspca_dev.usb_err < 0)
77 		return;
78 
79 	value = *data++;
80 	memcpy(sd->gspca_dev.usb_buf, data, 6);
81 
82 	/* Avoid things going to fast for the bridge with a xhci host */
83 	udelay(150);
84 	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0,
85 			      USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE,
86 			      value, 0x06, sd->gspca_dev.usb_buf, 6, 500);
87 	if (ret < 0) {
88 		pr_err("Write FSB registers failed (%d)\n", ret);
89 		sd->gspca_dev.usb_err = ret;
90 	}
91 }
92 
93 /*--------------------------------------------------------------------------
94   Write data to the serial bus control register.
95   Return 0 on success, a negative number otherwise.
96   --------------------------------------------------------------------------*/
97 static void w9968cf_write_sb(struct sd *sd, u16 value)
98 {
99 	int ret;
100 
101 	if (sd->gspca_dev.usb_err < 0)
102 		return;
103 
104 	/* Avoid things going to fast for the bridge with a xhci host */
105 	udelay(150);
106 
107 	/* We don't use reg_w here, as that would cause all writes when
108 	   bitbanging i2c to be logged, making the logs impossible to read */
109 	ret = usb_control_msg(sd->gspca_dev.dev,
110 		usb_sndctrlpipe(sd->gspca_dev.dev, 0),
111 		0,
112 		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
113 		value, 0x01, NULL, 0, 500);
114 
115 	udelay(W9968CF_I2C_BUS_DELAY);
116 
117 	if (ret < 0) {
118 		pr_err("Write SB reg [01] %04x failed\n", value);
119 		sd->gspca_dev.usb_err = ret;
120 	}
121 }
122 
123 /*--------------------------------------------------------------------------
124   Read data from the serial bus control register.
125   Return 0 on success, a negative number otherwise.
126   --------------------------------------------------------------------------*/
127 static int w9968cf_read_sb(struct sd *sd)
128 {
129 	int ret;
130 
131 	if (sd->gspca_dev.usb_err < 0)
132 		return -1;
133 
134 	/* Avoid things going to fast for the bridge with a xhci host */
135 	udelay(150);
136 
137 	/* We don't use reg_r here, as the w9968cf is special and has 16
138 	   bit registers instead of 8 bit */
139 	ret = usb_control_msg(sd->gspca_dev.dev,
140 			usb_rcvctrlpipe(sd->gspca_dev.dev, 0),
141 			1,
142 			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
143 			0, 0x01, sd->gspca_dev.usb_buf, 2, 500);
144 	if (ret >= 0) {
145 		ret = sd->gspca_dev.usb_buf[0] |
146 		      (sd->gspca_dev.usb_buf[1] << 8);
147 	} else {
148 		pr_err("Read SB reg [01] failed\n");
149 		sd->gspca_dev.usb_err = ret;
150 	}
151 
152 	udelay(W9968CF_I2C_BUS_DELAY);
153 
154 	return ret;
155 }
156 
157 /*--------------------------------------------------------------------------
158   Upload quantization tables for the JPEG compression.
159   This function is called by w9968cf_start_transfer().
160   Return 0 on success, a negative number otherwise.
161   --------------------------------------------------------------------------*/
162 static void w9968cf_upload_quantizationtables(struct sd *sd)
163 {
164 	u16 a, b;
165 	int i, j;
166 
167 	reg_w(sd, 0x39, 0x0010); /* JPEG clock enable */
168 
169 	for (i = 0, j = 0; i < 32; i++, j += 2) {
170 		a = Y_QUANTABLE[j] | ((unsigned)(Y_QUANTABLE[j + 1]) << 8);
171 		b = UV_QUANTABLE[j] | ((unsigned)(UV_QUANTABLE[j + 1]) << 8);
172 		reg_w(sd, 0x40 + i, a);
173 		reg_w(sd, 0x60 + i, b);
174 	}
175 	reg_w(sd, 0x39, 0x0012); /* JPEG encoder enable */
176 }
177 
178 /****************************************************************************
179  * Low-level I2C I/O functions.                                             *
180  * The adapter supports the following I2C transfer functions:               *
181  * i2c_adap_fastwrite_byte_data() (at 400 kHz bit frequency only)           *
182  * i2c_adap_read_byte_data()                                                *
183  * i2c_adap_read_byte()                                                     *
184  ****************************************************************************/
185 
186 static void w9968cf_smbus_start(struct sd *sd)
187 {
188 	w9968cf_write_sb(sd, 0x0011); /* SDE=1, SDA=0, SCL=1 */
189 	w9968cf_write_sb(sd, 0x0010); /* SDE=1, SDA=0, SCL=0 */
190 }
191 
192 static void w9968cf_smbus_stop(struct sd *sd)
193 {
194 	w9968cf_write_sb(sd, 0x0010); /* SDE=1, SDA=0, SCL=0 */
195 	w9968cf_write_sb(sd, 0x0011); /* SDE=1, SDA=0, SCL=1 */
196 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
197 }
198 
199 static void w9968cf_smbus_write_byte(struct sd *sd, u8 v)
200 {
201 	u8 bit;
202 	int sda;
203 
204 	for (bit = 0 ; bit < 8 ; bit++) {
205 		sda = (v & 0x80) ? 2 : 0;
206 		v <<= 1;
207 		/* SDE=1, SDA=sda, SCL=0 */
208 		w9968cf_write_sb(sd, 0x10 | sda);
209 		/* SDE=1, SDA=sda, SCL=1 */
210 		w9968cf_write_sb(sd, 0x11 | sda);
211 		/* SDE=1, SDA=sda, SCL=0 */
212 		w9968cf_write_sb(sd, 0x10 | sda);
213 	}
214 }
215 
216 static void w9968cf_smbus_read_byte(struct sd *sd, u8 *v)
217 {
218 	u8 bit;
219 
220 	/* No need to ensure SDA is high as we are always called after
221 	   read_ack which ends with SDA high */
222 	*v = 0;
223 	for (bit = 0 ; bit < 8 ; bit++) {
224 		*v <<= 1;
225 		/* SDE=1, SDA=1, SCL=1 */
226 		w9968cf_write_sb(sd, 0x0013);
227 		*v |= (w9968cf_read_sb(sd) & 0x0008) ? 1 : 0;
228 		/* SDE=1, SDA=1, SCL=0 */
229 		w9968cf_write_sb(sd, 0x0012);
230 	}
231 }
232 
233 static void w9968cf_smbus_write_nack(struct sd *sd)
234 {
235 	/* No need to ensure SDA is high as we are always called after
236 	   read_byte which ends with SDA high */
237 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
238 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
239 }
240 
241 static void w9968cf_smbus_read_ack(struct sd *sd)
242 {
243 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
244 	int sda;
245 
246 	/* Ensure SDA is high before raising clock to avoid a spurious stop */
247 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
248 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
249 	sda = w9968cf_read_sb(sd);
250 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
251 	if (sda >= 0 && (sda & 0x08)) {
252 		PDEBUG(D_USBI, "Did not receive i2c ACK");
253 		sd->gspca_dev.usb_err = -EIO;
254 	}
255 }
256 
257 /* SMBus protocol: S Addr Wr [A] Subaddr [A] Value [A] P */
258 static void w9968cf_i2c_w(struct sd *sd, u8 reg, u8 value)
259 {
260 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
261 	u16* data = (u16 *)sd->gspca_dev.usb_buf;
262 
263 	data[0] = 0x082f | ((sd->sensor_addr & 0x80) ? 0x1500 : 0x0);
264 	data[0] |= (sd->sensor_addr & 0x40) ? 0x4000 : 0x0;
265 	data[1] = 0x2082 | ((sd->sensor_addr & 0x40) ? 0x0005 : 0x0);
266 	data[1] |= (sd->sensor_addr & 0x20) ? 0x0150 : 0x0;
267 	data[1] |= (sd->sensor_addr & 0x10) ? 0x5400 : 0x0;
268 	data[2] = 0x8208 | ((sd->sensor_addr & 0x08) ? 0x0015 : 0x0);
269 	data[2] |= (sd->sensor_addr & 0x04) ? 0x0540 : 0x0;
270 	data[2] |= (sd->sensor_addr & 0x02) ? 0x5000 : 0x0;
271 	data[3] = 0x1d20 | ((sd->sensor_addr & 0x02) ? 0x0001 : 0x0);
272 	data[3] |= (sd->sensor_addr & 0x01) ? 0x0054 : 0x0;
273 
274 	w9968cf_write_fsb(sd, data);
275 
276 	data[0] = 0x8208 | ((reg & 0x80) ? 0x0015 : 0x0);
277 	data[0] |= (reg & 0x40) ? 0x0540 : 0x0;
278 	data[0] |= (reg & 0x20) ? 0x5000 : 0x0;
279 	data[1] = 0x0820 | ((reg & 0x20) ? 0x0001 : 0x0);
280 	data[1] |= (reg & 0x10) ? 0x0054 : 0x0;
281 	data[1] |= (reg & 0x08) ? 0x1500 : 0x0;
282 	data[1] |= (reg & 0x04) ? 0x4000 : 0x0;
283 	data[2] = 0x2082 | ((reg & 0x04) ? 0x0005 : 0x0);
284 	data[2] |= (reg & 0x02) ? 0x0150 : 0x0;
285 	data[2] |= (reg & 0x01) ? 0x5400 : 0x0;
286 	data[3] = 0x001d;
287 
288 	w9968cf_write_fsb(sd, data);
289 
290 	data[0] = 0x8208 | ((value & 0x80) ? 0x0015 : 0x0);
291 	data[0] |= (value & 0x40) ? 0x0540 : 0x0;
292 	data[0] |= (value & 0x20) ? 0x5000 : 0x0;
293 	data[1] = 0x0820 | ((value & 0x20) ? 0x0001 : 0x0);
294 	data[1] |= (value & 0x10) ? 0x0054 : 0x0;
295 	data[1] |= (value & 0x08) ? 0x1500 : 0x0;
296 	data[1] |= (value & 0x04) ? 0x4000 : 0x0;
297 	data[2] = 0x2082 | ((value & 0x04) ? 0x0005 : 0x0);
298 	data[2] |= (value & 0x02) ? 0x0150 : 0x0;
299 	data[2] |= (value & 0x01) ? 0x5400 : 0x0;
300 	data[3] = 0xfe1d;
301 
302 	w9968cf_write_fsb(sd, data);
303 
304 	PDEBUG(D_USBO, "i2c 0x%02x -> [0x%02x]", value, reg);
305 }
306 
307 /* SMBus protocol: S Addr Wr [A] Subaddr [A] P S Addr+1 Rd [A] [Value] NA P */
308 static int w9968cf_i2c_r(struct sd *sd, u8 reg)
309 {
310 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
311 	int ret = 0;
312 	u8 value;
313 
314 	/* Fast serial bus data control disable */
315 	w9968cf_write_sb(sd, 0x0013); /* don't change ! */
316 
317 	w9968cf_smbus_start(sd);
318 	w9968cf_smbus_write_byte(sd, sd->sensor_addr);
319 	w9968cf_smbus_read_ack(sd);
320 	w9968cf_smbus_write_byte(sd, reg);
321 	w9968cf_smbus_read_ack(sd);
322 	w9968cf_smbus_stop(sd);
323 	w9968cf_smbus_start(sd);
324 	w9968cf_smbus_write_byte(sd, sd->sensor_addr + 1);
325 	w9968cf_smbus_read_ack(sd);
326 	w9968cf_smbus_read_byte(sd, &value);
327 	/* signal we don't want to read anymore, the v4l1 driver used to
328 	   send an ack here which is very wrong! (and then fixed
329 	   the issues this gave by retrying reads) */
330 	w9968cf_smbus_write_nack(sd);
331 	w9968cf_smbus_stop(sd);
332 
333 	/* Fast serial bus data control re-enable */
334 	w9968cf_write_sb(sd, 0x0030);
335 
336 	if (sd->gspca_dev.usb_err >= 0) {
337 		ret = value;
338 		PDEBUG(D_USBI, "i2c [0x%02X] -> 0x%02X", reg, value);
339 	} else
340 		PERR("i2c read [0x%02x] failed", reg);
341 
342 	return ret;
343 }
344 
345 /*--------------------------------------------------------------------------
346   Turn on the LED on some webcams. A beep should be heard too.
347   Return 0 on success, a negative number otherwise.
348   --------------------------------------------------------------------------*/
349 static void w9968cf_configure(struct sd *sd)
350 {
351 	reg_w(sd, 0x00, 0xff00); /* power-down */
352 	reg_w(sd, 0x00, 0xbf17); /* reset everything */
353 	reg_w(sd, 0x00, 0xbf10); /* normal operation */
354 	reg_w(sd, 0x01, 0x0010); /* serial bus, SDS high */
355 	reg_w(sd, 0x01, 0x0000); /* serial bus, SDS low */
356 	reg_w(sd, 0x01, 0x0010); /* ..high 'beep-beep' */
357 	reg_w(sd, 0x01, 0x0030); /* Set sda scl to FSB mode */
358 
359 	sd->stopped = 1;
360 }
361 
362 static void w9968cf_init(struct sd *sd)
363 {
364 	unsigned long hw_bufsize = sd->sif ? (352 * 288 * 2) : (640 * 480 * 2),
365 		      y0 = 0x0000,
366 		      u0 = y0 + hw_bufsize / 2,
367 		      v0 = u0 + hw_bufsize / 4,
368 		      y1 = v0 + hw_bufsize / 4,
369 		      u1 = y1 + hw_bufsize / 2,
370 		      v1 = u1 + hw_bufsize / 4;
371 
372 	reg_w(sd, 0x00, 0xff00); /* power off */
373 	reg_w(sd, 0x00, 0xbf10); /* power on */
374 
375 	reg_w(sd, 0x03, 0x405d); /* DRAM timings */
376 	reg_w(sd, 0x04, 0x0030); /* SDRAM timings */
377 
378 	reg_w(sd, 0x20, y0 & 0xffff); /* Y buf.0, low */
379 	reg_w(sd, 0x21, y0 >> 16);    /* Y buf.0, high */
380 	reg_w(sd, 0x24, u0 & 0xffff); /* U buf.0, low */
381 	reg_w(sd, 0x25, u0 >> 16);    /* U buf.0, high */
382 	reg_w(sd, 0x28, v0 & 0xffff); /* V buf.0, low */
383 	reg_w(sd, 0x29, v0 >> 16);    /* V buf.0, high */
384 
385 	reg_w(sd, 0x22, y1 & 0xffff); /* Y buf.1, low */
386 	reg_w(sd, 0x23, y1 >> 16);    /* Y buf.1, high */
387 	reg_w(sd, 0x26, u1 & 0xffff); /* U buf.1, low */
388 	reg_w(sd, 0x27, u1 >> 16);    /* U buf.1, high */
389 	reg_w(sd, 0x2a, v1 & 0xffff); /* V buf.1, low */
390 	reg_w(sd, 0x2b, v1 >> 16);    /* V buf.1, high */
391 
392 	reg_w(sd, 0x32, y1 & 0xffff); /* JPEG buf 0 low */
393 	reg_w(sd, 0x33, y1 >> 16);    /* JPEG buf 0 high */
394 
395 	reg_w(sd, 0x34, y1 & 0xffff); /* JPEG buf 1 low */
396 	reg_w(sd, 0x35, y1 >> 16);    /* JPEG bug 1 high */
397 
398 	reg_w(sd, 0x36, 0x0000);/* JPEG restart interval */
399 	reg_w(sd, 0x37, 0x0804);/*JPEG VLE FIFO threshold*/
400 	reg_w(sd, 0x38, 0x0000);/* disable hw up-scaling */
401 	reg_w(sd, 0x3f, 0x0000); /* JPEG/MCTL test data */
402 }
403 
404 static void w9968cf_set_crop_window(struct sd *sd)
405 {
406 	int start_cropx, start_cropy,  x, y, fw, fh, cw, ch,
407 	    max_width, max_height;
408 
409 	if (sd->sif) {
410 		max_width  = 352;
411 		max_height = 288;
412 	} else {
413 		max_width  = 640;
414 		max_height = 480;
415 	}
416 
417 	if (sd->sensor == SEN_OV7620) {
418 		/*
419 		 * Sigh, this is dependend on the clock / framerate changes
420 		 * made by the frequency control, sick.
421 		 *
422 		 * Note we cannot use v4l2_ctrl_g_ctrl here, as we get called
423 		 * from ov519.c:setfreq() with the ctrl lock held!
424 		 */
425 		if (sd->freq->val == 1) {
426 			start_cropx = 277;
427 			start_cropy = 37;
428 		} else {
429 			start_cropx = 105;
430 			start_cropy = 37;
431 		}
432 	} else {
433 		start_cropx = 320;
434 		start_cropy = 35;
435 	}
436 
437 	/* Work around to avoid FP arithmetics */
438 	#define SC(x) ((x) << 10)
439 
440 	/* Scaling factors */
441 	fw = SC(sd->gspca_dev.pixfmt.width) / max_width;
442 	fh = SC(sd->gspca_dev.pixfmt.height) / max_height;
443 
444 	cw = (fw >= fh) ? max_width : SC(sd->gspca_dev.pixfmt.width) / fh;
445 	ch = (fw >= fh) ? SC(sd->gspca_dev.pixfmt.height) / fw : max_height;
446 
447 	sd->sensor_width = max_width;
448 	sd->sensor_height = max_height;
449 
450 	x = (max_width - cw) / 2;
451 	y = (max_height - ch) / 2;
452 
453 	reg_w(sd, 0x10, start_cropx + x);
454 	reg_w(sd, 0x11, start_cropy + y);
455 	reg_w(sd, 0x12, start_cropx + x + cw);
456 	reg_w(sd, 0x13, start_cropy + y + ch);
457 }
458 
459 static void w9968cf_mode_init_regs(struct sd *sd)
460 {
461 	int val, vs_polarity, hs_polarity;
462 
463 	w9968cf_set_crop_window(sd);
464 
465 	reg_w(sd, 0x14, sd->gspca_dev.pixfmt.width);
466 	reg_w(sd, 0x15, sd->gspca_dev.pixfmt.height);
467 
468 	/* JPEG width & height */
469 	reg_w(sd, 0x30, sd->gspca_dev.pixfmt.width);
470 	reg_w(sd, 0x31, sd->gspca_dev.pixfmt.height);
471 
472 	/* Y & UV frame buffer strides (in WORD) */
473 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
474 	    V4L2_PIX_FMT_JPEG) {
475 		reg_w(sd, 0x2c, sd->gspca_dev.pixfmt.width / 2);
476 		reg_w(sd, 0x2d, sd->gspca_dev.pixfmt.width / 4);
477 	} else
478 		reg_w(sd, 0x2c, sd->gspca_dev.pixfmt.width);
479 
480 	reg_w(sd, 0x00, 0xbf17); /* reset everything */
481 	reg_w(sd, 0x00, 0xbf10); /* normal operation */
482 
483 	/* Transfer size in WORDS (for UYVY format only) */
484 	val = sd->gspca_dev.pixfmt.width * sd->gspca_dev.pixfmt.height;
485 	reg_w(sd, 0x3d, val & 0xffff); /* low bits */
486 	reg_w(sd, 0x3e, val >> 16);    /* high bits */
487 
488 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
489 	    V4L2_PIX_FMT_JPEG) {
490 		/* We may get called multiple times (usb isoc bw negotiat.) */
491 		jpeg_define(sd->jpeg_hdr, sd->gspca_dev.pixfmt.height,
492 			    sd->gspca_dev.pixfmt.width, 0x22); /* JPEG 420 */
493 		jpeg_set_qual(sd->jpeg_hdr, v4l2_ctrl_g_ctrl(sd->jpegqual));
494 		w9968cf_upload_quantizationtables(sd);
495 		v4l2_ctrl_grab(sd->jpegqual, true);
496 	}
497 
498 	/* Video Capture Control Register */
499 	if (sd->sensor == SEN_OV7620) {
500 		/* Seems to work around a bug in the image sensor */
501 		vs_polarity = 1;
502 		hs_polarity = 1;
503 	} else {
504 		vs_polarity = 1;
505 		hs_polarity = 0;
506 	}
507 
508 	val = (vs_polarity << 12) | (hs_polarity << 11);
509 
510 	/* NOTE: We may not have enough memory to do double buffering while
511 	   doing compression (amount of memory differs per model cam).
512 	   So we use the second image buffer also as jpeg stream buffer
513 	   (see w9968cf_init), and disable double buffering. */
514 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
515 	    V4L2_PIX_FMT_JPEG) {
516 		/* val |= 0x0002; YUV422P */
517 		val |= 0x0003; /* YUV420P */
518 	} else
519 		val |= 0x0080; /* Enable HW double buffering */
520 
521 	/* val |= 0x0020; enable clamping */
522 	/* val |= 0x0008; enable (1-2-1) filter */
523 	/* val |= 0x000c; enable (2-3-6-3-2) filter */
524 
525 	val |= 0x8000; /* capt. enable */
526 
527 	reg_w(sd, 0x16, val);
528 
529 	sd->gspca_dev.empty_packet = 0;
530 }
531 
532 static void w9968cf_stop0(struct sd *sd)
533 {
534 	v4l2_ctrl_grab(sd->jpegqual, false);
535 	reg_w(sd, 0x39, 0x0000); /* disable JPEG encoder */
536 	reg_w(sd, 0x16, 0x0000); /* stop video capture */
537 }
538 
539 /* The w9968cf docs say that a 0 sized packet means EOF (and also SOF
540    for the next frame). This seems to simply not be true when operating
541    in JPEG mode, in this case there may be empty packets within the
542    frame. So in JPEG mode use the JPEG SOI marker to detect SOF.
543 
544    Note to make things even more interesting the w9968cf sends *PLANAR* jpeg,
545    to be precise it sends: SOI, SOF, DRI, SOS, Y-data, SOS, U-data, SOS,
546    V-data, EOI. */
547 static void w9968cf_pkt_scan(struct gspca_dev *gspca_dev,
548 			u8 *data,			/* isoc packet */
549 			int len)			/* iso packet length */
550 {
551 	struct sd *sd = (struct sd *) gspca_dev;
552 
553 	if (w9968cf_vga_mode[gspca_dev->curr_mode].pixelformat ==
554 	    V4L2_PIX_FMT_JPEG) {
555 		if (len >= 2 &&
556 		    data[0] == 0xff &&
557 		    data[1] == 0xd8) {
558 			gspca_frame_add(gspca_dev, LAST_PACKET,
559 					NULL, 0);
560 			gspca_frame_add(gspca_dev, FIRST_PACKET,
561 					sd->jpeg_hdr, JPEG_HDR_SZ);
562 			/* Strip the ff d8, our own header (which adds
563 			   huffman and quantization tables) already has this */
564 			len -= 2;
565 			data += 2;
566 		}
567 	} else {
568 		/* In UYVY mode an empty packet signals EOF */
569 		if (gspca_dev->empty_packet) {
570 			gspca_frame_add(gspca_dev, LAST_PACKET,
571 						NULL, 0);
572 			gspca_frame_add(gspca_dev, FIRST_PACKET,
573 					NULL, 0);
574 			gspca_dev->empty_packet = 0;
575 		}
576 	}
577 	gspca_frame_add(gspca_dev, INTER_PACKET, data, len);
578 }
579