xref: /openbmc/linux/drivers/media/usb/gspca/w996Xcf.c (revision e3b9f1e8)
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  */
22 
23 /* Note this is not a stand alone driver, it gets included in ov519.c, this
24    is a bit of a hack, but it needs the driver code for a lot of different
25    ov sensors which is already present in ov519.c (the old v4l1 driver used
26    the ovchipcam framework). When we have the time we really should move
27    the sensor drivers to v4l2 sub drivers, and properly split of this
28    driver from ov519.c */
29 
30 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
31 
32 #define W9968CF_I2C_BUS_DELAY    4 /* delay in us for I2C bit r/w operations */
33 
34 #define Y_QUANTABLE (&sd->jpeg_hdr[JPEG_QT0_OFFSET])
35 #define UV_QUANTABLE (&sd->jpeg_hdr[JPEG_QT1_OFFSET])
36 
37 static const struct v4l2_pix_format w9968cf_vga_mode[] = {
38 	{160, 120, V4L2_PIX_FMT_UYVY, V4L2_FIELD_NONE,
39 		.bytesperline = 160 * 2,
40 		.sizeimage = 160 * 120 * 2,
41 		.colorspace = V4L2_COLORSPACE_JPEG},
42 	{176, 144, V4L2_PIX_FMT_UYVY, V4L2_FIELD_NONE,
43 		.bytesperline = 176 * 2,
44 		.sizeimage = 176 * 144 * 2,
45 		.colorspace = V4L2_COLORSPACE_JPEG},
46 	{320, 240, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
47 		.bytesperline = 320 * 2,
48 		.sizeimage = 320 * 240 * 2,
49 		.colorspace = V4L2_COLORSPACE_JPEG},
50 	{352, 288, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
51 		.bytesperline = 352 * 2,
52 		.sizeimage = 352 * 288 * 2,
53 		.colorspace = V4L2_COLORSPACE_JPEG},
54 	{640, 480, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
55 		.bytesperline = 640 * 2,
56 		.sizeimage = 640 * 480 * 2,
57 		.colorspace = V4L2_COLORSPACE_JPEG},
58 };
59 
60 static void reg_w(struct sd *sd, u16 index, u16 value);
61 
62 /*--------------------------------------------------------------------------
63   Write 64-bit data to the fast serial bus registers.
64   Return 0 on success, -1 otherwise.
65   --------------------------------------------------------------------------*/
66 static void w9968cf_write_fsb(struct sd *sd, u16* data)
67 {
68 	struct usb_device *udev = sd->gspca_dev.dev;
69 	u16 value;
70 	int ret;
71 
72 	if (sd->gspca_dev.usb_err < 0)
73 		return;
74 
75 	value = *data++;
76 	memcpy(sd->gspca_dev.usb_buf, data, 6);
77 
78 	/* Avoid things going to fast for the bridge with a xhci host */
79 	udelay(150);
80 	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0,
81 			      USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE,
82 			      value, 0x06, sd->gspca_dev.usb_buf, 6, 500);
83 	if (ret < 0) {
84 		pr_err("Write FSB registers failed (%d)\n", ret);
85 		sd->gspca_dev.usb_err = ret;
86 	}
87 }
88 
89 /*--------------------------------------------------------------------------
90   Write data to the serial bus control register.
91   Return 0 on success, a negative number otherwise.
92   --------------------------------------------------------------------------*/
93 static void w9968cf_write_sb(struct sd *sd, u16 value)
94 {
95 	int ret;
96 
97 	if (sd->gspca_dev.usb_err < 0)
98 		return;
99 
100 	/* Avoid things going to fast for the bridge with a xhci host */
101 	udelay(150);
102 
103 	/* We don't use reg_w here, as that would cause all writes when
104 	   bitbanging i2c to be logged, making the logs impossible to read */
105 	ret = usb_control_msg(sd->gspca_dev.dev,
106 		usb_sndctrlpipe(sd->gspca_dev.dev, 0),
107 		0,
108 		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
109 		value, 0x01, NULL, 0, 500);
110 
111 	udelay(W9968CF_I2C_BUS_DELAY);
112 
113 	if (ret < 0) {
114 		pr_err("Write SB reg [01] %04x failed\n", value);
115 		sd->gspca_dev.usb_err = ret;
116 	}
117 }
118 
119 /*--------------------------------------------------------------------------
120   Read data from the serial bus control register.
121   Return 0 on success, a negative number otherwise.
122   --------------------------------------------------------------------------*/
123 static int w9968cf_read_sb(struct sd *sd)
124 {
125 	int ret;
126 
127 	if (sd->gspca_dev.usb_err < 0)
128 		return -1;
129 
130 	/* Avoid things going to fast for the bridge with a xhci host */
131 	udelay(150);
132 
133 	/* We don't use reg_r here, as the w9968cf is special and has 16
134 	   bit registers instead of 8 bit */
135 	ret = usb_control_msg(sd->gspca_dev.dev,
136 			usb_rcvctrlpipe(sd->gspca_dev.dev, 0),
137 			1,
138 			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
139 			0, 0x01, sd->gspca_dev.usb_buf, 2, 500);
140 	if (ret >= 0) {
141 		ret = sd->gspca_dev.usb_buf[0] |
142 		      (sd->gspca_dev.usb_buf[1] << 8);
143 	} else {
144 		pr_err("Read SB reg [01] failed\n");
145 		sd->gspca_dev.usb_err = ret;
146 	}
147 
148 	udelay(W9968CF_I2C_BUS_DELAY);
149 
150 	return ret;
151 }
152 
153 /*--------------------------------------------------------------------------
154   Upload quantization tables for the JPEG compression.
155   This function is called by w9968cf_start_transfer().
156   Return 0 on success, a negative number otherwise.
157   --------------------------------------------------------------------------*/
158 static void w9968cf_upload_quantizationtables(struct sd *sd)
159 {
160 	u16 a, b;
161 	int i, j;
162 
163 	reg_w(sd, 0x39, 0x0010); /* JPEG clock enable */
164 
165 	for (i = 0, j = 0; i < 32; i++, j += 2) {
166 		a = Y_QUANTABLE[j] | ((unsigned)(Y_QUANTABLE[j + 1]) << 8);
167 		b = UV_QUANTABLE[j] | ((unsigned)(UV_QUANTABLE[j + 1]) << 8);
168 		reg_w(sd, 0x40 + i, a);
169 		reg_w(sd, 0x60 + i, b);
170 	}
171 	reg_w(sd, 0x39, 0x0012); /* JPEG encoder enable */
172 }
173 
174 /****************************************************************************
175  * Low-level I2C I/O functions.                                             *
176  * The adapter supports the following I2C transfer functions:               *
177  * i2c_adap_fastwrite_byte_data() (at 400 kHz bit frequency only)           *
178  * i2c_adap_read_byte_data()                                                *
179  * i2c_adap_read_byte()                                                     *
180  ****************************************************************************/
181 
182 static void w9968cf_smbus_start(struct sd *sd)
183 {
184 	w9968cf_write_sb(sd, 0x0011); /* SDE=1, SDA=0, SCL=1 */
185 	w9968cf_write_sb(sd, 0x0010); /* SDE=1, SDA=0, SCL=0 */
186 }
187 
188 static void w9968cf_smbus_stop(struct sd *sd)
189 {
190 	w9968cf_write_sb(sd, 0x0010); /* SDE=1, SDA=0, SCL=0 */
191 	w9968cf_write_sb(sd, 0x0011); /* SDE=1, SDA=0, SCL=1 */
192 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
193 }
194 
195 static void w9968cf_smbus_write_byte(struct sd *sd, u8 v)
196 {
197 	u8 bit;
198 	int sda;
199 
200 	for (bit = 0 ; bit < 8 ; bit++) {
201 		sda = (v & 0x80) ? 2 : 0;
202 		v <<= 1;
203 		/* SDE=1, SDA=sda, SCL=0 */
204 		w9968cf_write_sb(sd, 0x10 | sda);
205 		/* SDE=1, SDA=sda, SCL=1 */
206 		w9968cf_write_sb(sd, 0x11 | sda);
207 		/* SDE=1, SDA=sda, SCL=0 */
208 		w9968cf_write_sb(sd, 0x10 | sda);
209 	}
210 }
211 
212 static void w9968cf_smbus_read_byte(struct sd *sd, u8 *v)
213 {
214 	u8 bit;
215 
216 	/* No need to ensure SDA is high as we are always called after
217 	   read_ack which ends with SDA high */
218 	*v = 0;
219 	for (bit = 0 ; bit < 8 ; bit++) {
220 		*v <<= 1;
221 		/* SDE=1, SDA=1, SCL=1 */
222 		w9968cf_write_sb(sd, 0x0013);
223 		*v |= (w9968cf_read_sb(sd) & 0x0008) ? 1 : 0;
224 		/* SDE=1, SDA=1, SCL=0 */
225 		w9968cf_write_sb(sd, 0x0012);
226 	}
227 }
228 
229 static void w9968cf_smbus_write_nack(struct sd *sd)
230 {
231 	/* No need to ensure SDA is high as we are always called after
232 	   read_byte which ends with SDA high */
233 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
234 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
235 }
236 
237 static void w9968cf_smbus_read_ack(struct sd *sd)
238 {
239 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
240 	int sda;
241 
242 	/* Ensure SDA is high before raising clock to avoid a spurious stop */
243 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
244 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
245 	sda = w9968cf_read_sb(sd);
246 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
247 	if (sda >= 0 && (sda & 0x08)) {
248 		gspca_dbg(gspca_dev, D_USBI, "Did not receive i2c ACK\n");
249 		sd->gspca_dev.usb_err = -EIO;
250 	}
251 }
252 
253 /* SMBus protocol: S Addr Wr [A] Subaddr [A] Value [A] P */
254 static void w9968cf_i2c_w(struct sd *sd, u8 reg, u8 value)
255 {
256 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
257 	u16* data = (u16 *)sd->gspca_dev.usb_buf;
258 
259 	data[0] = 0x082f | ((sd->sensor_addr & 0x80) ? 0x1500 : 0x0);
260 	data[0] |= (sd->sensor_addr & 0x40) ? 0x4000 : 0x0;
261 	data[1] = 0x2082 | ((sd->sensor_addr & 0x40) ? 0x0005 : 0x0);
262 	data[1] |= (sd->sensor_addr & 0x20) ? 0x0150 : 0x0;
263 	data[1] |= (sd->sensor_addr & 0x10) ? 0x5400 : 0x0;
264 	data[2] = 0x8208 | ((sd->sensor_addr & 0x08) ? 0x0015 : 0x0);
265 	data[2] |= (sd->sensor_addr & 0x04) ? 0x0540 : 0x0;
266 	data[2] |= (sd->sensor_addr & 0x02) ? 0x5000 : 0x0;
267 	data[3] = 0x1d20 | ((sd->sensor_addr & 0x02) ? 0x0001 : 0x0);
268 	data[3] |= (sd->sensor_addr & 0x01) ? 0x0054 : 0x0;
269 
270 	w9968cf_write_fsb(sd, data);
271 
272 	data[0] = 0x8208 | ((reg & 0x80) ? 0x0015 : 0x0);
273 	data[0] |= (reg & 0x40) ? 0x0540 : 0x0;
274 	data[0] |= (reg & 0x20) ? 0x5000 : 0x0;
275 	data[1] = 0x0820 | ((reg & 0x20) ? 0x0001 : 0x0);
276 	data[1] |= (reg & 0x10) ? 0x0054 : 0x0;
277 	data[1] |= (reg & 0x08) ? 0x1500 : 0x0;
278 	data[1] |= (reg & 0x04) ? 0x4000 : 0x0;
279 	data[2] = 0x2082 | ((reg & 0x04) ? 0x0005 : 0x0);
280 	data[2] |= (reg & 0x02) ? 0x0150 : 0x0;
281 	data[2] |= (reg & 0x01) ? 0x5400 : 0x0;
282 	data[3] = 0x001d;
283 
284 	w9968cf_write_fsb(sd, data);
285 
286 	data[0] = 0x8208 | ((value & 0x80) ? 0x0015 : 0x0);
287 	data[0] |= (value & 0x40) ? 0x0540 : 0x0;
288 	data[0] |= (value & 0x20) ? 0x5000 : 0x0;
289 	data[1] = 0x0820 | ((value & 0x20) ? 0x0001 : 0x0);
290 	data[1] |= (value & 0x10) ? 0x0054 : 0x0;
291 	data[1] |= (value & 0x08) ? 0x1500 : 0x0;
292 	data[1] |= (value & 0x04) ? 0x4000 : 0x0;
293 	data[2] = 0x2082 | ((value & 0x04) ? 0x0005 : 0x0);
294 	data[2] |= (value & 0x02) ? 0x0150 : 0x0;
295 	data[2] |= (value & 0x01) ? 0x5400 : 0x0;
296 	data[3] = 0xfe1d;
297 
298 	w9968cf_write_fsb(sd, data);
299 
300 	gspca_dbg(gspca_dev, D_USBO, "i2c 0x%02x -> [0x%02x]\n", value, reg);
301 }
302 
303 /* SMBus protocol: S Addr Wr [A] Subaddr [A] P S Addr+1 Rd [A] [Value] NA P */
304 static int w9968cf_i2c_r(struct sd *sd, u8 reg)
305 {
306 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
307 	int ret = 0;
308 	u8 value;
309 
310 	/* Fast serial bus data control disable */
311 	w9968cf_write_sb(sd, 0x0013); /* don't change ! */
312 
313 	w9968cf_smbus_start(sd);
314 	w9968cf_smbus_write_byte(sd, sd->sensor_addr);
315 	w9968cf_smbus_read_ack(sd);
316 	w9968cf_smbus_write_byte(sd, reg);
317 	w9968cf_smbus_read_ack(sd);
318 	w9968cf_smbus_stop(sd);
319 	w9968cf_smbus_start(sd);
320 	w9968cf_smbus_write_byte(sd, sd->sensor_addr + 1);
321 	w9968cf_smbus_read_ack(sd);
322 	w9968cf_smbus_read_byte(sd, &value);
323 	/* signal we don't want to read anymore, the v4l1 driver used to
324 	   send an ack here which is very wrong! (and then fixed
325 	   the issues this gave by retrying reads) */
326 	w9968cf_smbus_write_nack(sd);
327 	w9968cf_smbus_stop(sd);
328 
329 	/* Fast serial bus data control re-enable */
330 	w9968cf_write_sb(sd, 0x0030);
331 
332 	if (sd->gspca_dev.usb_err >= 0) {
333 		ret = value;
334 		gspca_dbg(gspca_dev, D_USBI, "i2c [0x%02X] -> 0x%02X\n",
335 			  reg, value);
336 	} else
337 		gspca_err(gspca_dev, "i2c read [0x%02x] failed\n", reg);
338 
339 	return ret;
340 }
341 
342 /*--------------------------------------------------------------------------
343   Turn on the LED on some webcams. A beep should be heard too.
344   Return 0 on success, a negative number otherwise.
345   --------------------------------------------------------------------------*/
346 static void w9968cf_configure(struct sd *sd)
347 {
348 	reg_w(sd, 0x00, 0xff00); /* power-down */
349 	reg_w(sd, 0x00, 0xbf17); /* reset everything */
350 	reg_w(sd, 0x00, 0xbf10); /* normal operation */
351 	reg_w(sd, 0x01, 0x0010); /* serial bus, SDS high */
352 	reg_w(sd, 0x01, 0x0000); /* serial bus, SDS low */
353 	reg_w(sd, 0x01, 0x0010); /* ..high 'beep-beep' */
354 	reg_w(sd, 0x01, 0x0030); /* Set sda scl to FSB mode */
355 
356 	sd->stopped = 1;
357 }
358 
359 static void w9968cf_init(struct sd *sd)
360 {
361 	unsigned long hw_bufsize = sd->sif ? (352 * 288 * 2) : (640 * 480 * 2),
362 		      y0 = 0x0000,
363 		      u0 = y0 + hw_bufsize / 2,
364 		      v0 = u0 + hw_bufsize / 4,
365 		      y1 = v0 + hw_bufsize / 4,
366 		      u1 = y1 + hw_bufsize / 2,
367 		      v1 = u1 + hw_bufsize / 4;
368 
369 	reg_w(sd, 0x00, 0xff00); /* power off */
370 	reg_w(sd, 0x00, 0xbf10); /* power on */
371 
372 	reg_w(sd, 0x03, 0x405d); /* DRAM timings */
373 	reg_w(sd, 0x04, 0x0030); /* SDRAM timings */
374 
375 	reg_w(sd, 0x20, y0 & 0xffff); /* Y buf.0, low */
376 	reg_w(sd, 0x21, y0 >> 16);    /* Y buf.0, high */
377 	reg_w(sd, 0x24, u0 & 0xffff); /* U buf.0, low */
378 	reg_w(sd, 0x25, u0 >> 16);    /* U buf.0, high */
379 	reg_w(sd, 0x28, v0 & 0xffff); /* V buf.0, low */
380 	reg_w(sd, 0x29, v0 >> 16);    /* V buf.0, high */
381 
382 	reg_w(sd, 0x22, y1 & 0xffff); /* Y buf.1, low */
383 	reg_w(sd, 0x23, y1 >> 16);    /* Y buf.1, high */
384 	reg_w(sd, 0x26, u1 & 0xffff); /* U buf.1, low */
385 	reg_w(sd, 0x27, u1 >> 16);    /* U buf.1, high */
386 	reg_w(sd, 0x2a, v1 & 0xffff); /* V buf.1, low */
387 	reg_w(sd, 0x2b, v1 >> 16);    /* V buf.1, high */
388 
389 	reg_w(sd, 0x32, y1 & 0xffff); /* JPEG buf 0 low */
390 	reg_w(sd, 0x33, y1 >> 16);    /* JPEG buf 0 high */
391 
392 	reg_w(sd, 0x34, y1 & 0xffff); /* JPEG buf 1 low */
393 	reg_w(sd, 0x35, y1 >> 16);    /* JPEG bug 1 high */
394 
395 	reg_w(sd, 0x36, 0x0000);/* JPEG restart interval */
396 	reg_w(sd, 0x37, 0x0804);/*JPEG VLE FIFO threshold*/
397 	reg_w(sd, 0x38, 0x0000);/* disable hw up-scaling */
398 	reg_w(sd, 0x3f, 0x0000); /* JPEG/MCTL test data */
399 }
400 
401 static void w9968cf_set_crop_window(struct sd *sd)
402 {
403 	int start_cropx, start_cropy,  x, y, fw, fh, cw, ch,
404 	    max_width, max_height;
405 
406 	if (sd->sif) {
407 		max_width  = 352;
408 		max_height = 288;
409 	} else {
410 		max_width  = 640;
411 		max_height = 480;
412 	}
413 
414 	if (sd->sensor == SEN_OV7620) {
415 		/*
416 		 * Sigh, this is dependend on the clock / framerate changes
417 		 * made by the frequency control, sick.
418 		 *
419 		 * Note we cannot use v4l2_ctrl_g_ctrl here, as we get called
420 		 * from ov519.c:setfreq() with the ctrl lock held!
421 		 */
422 		if (sd->freq->val == 1) {
423 			start_cropx = 277;
424 			start_cropy = 37;
425 		} else {
426 			start_cropx = 105;
427 			start_cropy = 37;
428 		}
429 	} else {
430 		start_cropx = 320;
431 		start_cropy = 35;
432 	}
433 
434 	/* Work around to avoid FP arithmetics */
435 	#define SC(x) ((x) << 10)
436 
437 	/* Scaling factors */
438 	fw = SC(sd->gspca_dev.pixfmt.width) / max_width;
439 	fh = SC(sd->gspca_dev.pixfmt.height) / max_height;
440 
441 	cw = (fw >= fh) ? max_width : SC(sd->gspca_dev.pixfmt.width) / fh;
442 	ch = (fw >= fh) ? SC(sd->gspca_dev.pixfmt.height) / fw : max_height;
443 
444 	sd->sensor_width = max_width;
445 	sd->sensor_height = max_height;
446 
447 	x = (max_width - cw) / 2;
448 	y = (max_height - ch) / 2;
449 
450 	reg_w(sd, 0x10, start_cropx + x);
451 	reg_w(sd, 0x11, start_cropy + y);
452 	reg_w(sd, 0x12, start_cropx + x + cw);
453 	reg_w(sd, 0x13, start_cropy + y + ch);
454 }
455 
456 static void w9968cf_mode_init_regs(struct sd *sd)
457 {
458 	int val, vs_polarity, hs_polarity;
459 
460 	w9968cf_set_crop_window(sd);
461 
462 	reg_w(sd, 0x14, sd->gspca_dev.pixfmt.width);
463 	reg_w(sd, 0x15, sd->gspca_dev.pixfmt.height);
464 
465 	/* JPEG width & height */
466 	reg_w(sd, 0x30, sd->gspca_dev.pixfmt.width);
467 	reg_w(sd, 0x31, sd->gspca_dev.pixfmt.height);
468 
469 	/* Y & UV frame buffer strides (in WORD) */
470 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
471 	    V4L2_PIX_FMT_JPEG) {
472 		reg_w(sd, 0x2c, sd->gspca_dev.pixfmt.width / 2);
473 		reg_w(sd, 0x2d, sd->gspca_dev.pixfmt.width / 4);
474 	} else
475 		reg_w(sd, 0x2c, sd->gspca_dev.pixfmt.width);
476 
477 	reg_w(sd, 0x00, 0xbf17); /* reset everything */
478 	reg_w(sd, 0x00, 0xbf10); /* normal operation */
479 
480 	/* Transfer size in WORDS (for UYVY format only) */
481 	val = sd->gspca_dev.pixfmt.width * sd->gspca_dev.pixfmt.height;
482 	reg_w(sd, 0x3d, val & 0xffff); /* low bits */
483 	reg_w(sd, 0x3e, val >> 16);    /* high bits */
484 
485 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
486 	    V4L2_PIX_FMT_JPEG) {
487 		/* We may get called multiple times (usb isoc bw negotiat.) */
488 		jpeg_define(sd->jpeg_hdr, sd->gspca_dev.pixfmt.height,
489 			    sd->gspca_dev.pixfmt.width, 0x22); /* JPEG 420 */
490 		jpeg_set_qual(sd->jpeg_hdr, v4l2_ctrl_g_ctrl(sd->jpegqual));
491 		w9968cf_upload_quantizationtables(sd);
492 		v4l2_ctrl_grab(sd->jpegqual, true);
493 	}
494 
495 	/* Video Capture Control Register */
496 	if (sd->sensor == SEN_OV7620) {
497 		/* Seems to work around a bug in the image sensor */
498 		vs_polarity = 1;
499 		hs_polarity = 1;
500 	} else {
501 		vs_polarity = 1;
502 		hs_polarity = 0;
503 	}
504 
505 	val = (vs_polarity << 12) | (hs_polarity << 11);
506 
507 	/* NOTE: We may not have enough memory to do double buffering while
508 	   doing compression (amount of memory differs per model cam).
509 	   So we use the second image buffer also as jpeg stream buffer
510 	   (see w9968cf_init), and disable double buffering. */
511 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
512 	    V4L2_PIX_FMT_JPEG) {
513 		/* val |= 0x0002; YUV422P */
514 		val |= 0x0003; /* YUV420P */
515 	} else
516 		val |= 0x0080; /* Enable HW double buffering */
517 
518 	/* val |= 0x0020; enable clamping */
519 	/* val |= 0x0008; enable (1-2-1) filter */
520 	/* val |= 0x000c; enable (2-3-6-3-2) filter */
521 
522 	val |= 0x8000; /* capt. enable */
523 
524 	reg_w(sd, 0x16, val);
525 
526 	sd->gspca_dev.empty_packet = 0;
527 }
528 
529 static void w9968cf_stop0(struct sd *sd)
530 {
531 	v4l2_ctrl_grab(sd->jpegqual, false);
532 	reg_w(sd, 0x39, 0x0000); /* disable JPEG encoder */
533 	reg_w(sd, 0x16, 0x0000); /* stop video capture */
534 }
535 
536 /* The w9968cf docs say that a 0 sized packet means EOF (and also SOF
537    for the next frame). This seems to simply not be true when operating
538    in JPEG mode, in this case there may be empty packets within the
539    frame. So in JPEG mode use the JPEG SOI marker to detect SOF.
540 
541    Note to make things even more interesting the w9968cf sends *PLANAR* jpeg,
542    to be precise it sends: SOI, SOF, DRI, SOS, Y-data, SOS, U-data, SOS,
543    V-data, EOI. */
544 static void w9968cf_pkt_scan(struct gspca_dev *gspca_dev,
545 			u8 *data,			/* isoc packet */
546 			int len)			/* iso packet length */
547 {
548 	struct sd *sd = (struct sd *) gspca_dev;
549 
550 	if (w9968cf_vga_mode[gspca_dev->curr_mode].pixelformat ==
551 	    V4L2_PIX_FMT_JPEG) {
552 		if (len >= 2 &&
553 		    data[0] == 0xff &&
554 		    data[1] == 0xd8) {
555 			gspca_frame_add(gspca_dev, LAST_PACKET,
556 					NULL, 0);
557 			gspca_frame_add(gspca_dev, FIRST_PACKET,
558 					sd->jpeg_hdr, JPEG_HDR_SZ);
559 			/* Strip the ff d8, our own header (which adds
560 			   huffman and quantization tables) already has this */
561 			len -= 2;
562 			data += 2;
563 		}
564 	} else {
565 		/* In UYVY mode an empty packet signals EOF */
566 		if (gspca_dev->empty_packet) {
567 			gspca_frame_add(gspca_dev, LAST_PACKET,
568 						NULL, 0);
569 			gspca_frame_add(gspca_dev, FIRST_PACKET,
570 					NULL, 0);
571 			gspca_dev->empty_packet = 0;
572 		}
573 	}
574 	gspca_frame_add(gspca_dev, INTER_PACKET, data, len);
575 }
576