xref: /openbmc/linux/drivers/media/usb/gspca/w996Xcf.c (revision fb574682)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /**
3  *
4  * GSPCA sub driver for W996[78]CF JPEG USB Dual Mode Camera Chip.
5  *
6  * Copyright (C) 2009 Hans de Goede <hdegoede@redhat.com>
7  *
8  * This module is adapted from the in kernel v4l1 w9968cf driver:
9  *
10  * Copyright (C) 2002-2004 by Luca Risolia <luca.risolia@studio.unibo.it>
11  */
12 
13 /* Note this is not a stand alone driver, it gets included in ov519.c, this
14    is a bit of a hack, but it needs the driver code for a lot of different
15    ov sensors which is already present in ov519.c (the old v4l1 driver used
16    the ovchipcam framework). When we have the time we really should move
17    the sensor drivers to v4l2 sub drivers, and properly split of this
18    driver from ov519.c */
19 
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 
22 #define W9968CF_I2C_BUS_DELAY    4 /* delay in us for I2C bit r/w operations */
23 
24 #define Y_QUANTABLE (&sd->jpeg_hdr[JPEG_QT0_OFFSET])
25 #define UV_QUANTABLE (&sd->jpeg_hdr[JPEG_QT1_OFFSET])
26 
27 static const struct v4l2_pix_format w9968cf_vga_mode[] = {
28 	{160, 120, V4L2_PIX_FMT_UYVY, V4L2_FIELD_NONE,
29 		.bytesperline = 160 * 2,
30 		.sizeimage = 160 * 120 * 2,
31 		.colorspace = V4L2_COLORSPACE_JPEG},
32 	{176, 144, V4L2_PIX_FMT_UYVY, V4L2_FIELD_NONE,
33 		.bytesperline = 176 * 2,
34 		.sizeimage = 176 * 144 * 2,
35 		.colorspace = V4L2_COLORSPACE_JPEG},
36 	{320, 240, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
37 		.bytesperline = 320 * 2,
38 		.sizeimage = 320 * 240 * 2,
39 		.colorspace = V4L2_COLORSPACE_JPEG},
40 	{352, 288, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
41 		.bytesperline = 352 * 2,
42 		.sizeimage = 352 * 288 * 2,
43 		.colorspace = V4L2_COLORSPACE_JPEG},
44 	{640, 480, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
45 		.bytesperline = 640 * 2,
46 		.sizeimage = 640 * 480 * 2,
47 		.colorspace = V4L2_COLORSPACE_JPEG},
48 };
49 
50 static void reg_w(struct sd *sd, u16 index, u16 value);
51 
52 /*--------------------------------------------------------------------------
53   Write 64-bit data to the fast serial bus registers.
54   Return 0 on success, -1 otherwise.
55   --------------------------------------------------------------------------*/
56 static void w9968cf_write_fsb(struct sd *sd, u16* data)
57 {
58 	struct usb_device *udev = sd->gspca_dev.dev;
59 	u16 value;
60 	int ret;
61 
62 	if (sd->gspca_dev.usb_err < 0)
63 		return;
64 
65 	value = *data++;
66 	memcpy(sd->gspca_dev.usb_buf, data, 6);
67 
68 	/* Avoid things going to fast for the bridge with a xhci host */
69 	udelay(150);
70 	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0,
71 			      USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE,
72 			      value, 0x06, sd->gspca_dev.usb_buf, 6, 500);
73 	if (ret < 0) {
74 		pr_err("Write FSB registers failed (%d)\n", ret);
75 		sd->gspca_dev.usb_err = ret;
76 	}
77 }
78 
79 /*--------------------------------------------------------------------------
80   Write data to the serial bus control register.
81   Return 0 on success, a negative number otherwise.
82   --------------------------------------------------------------------------*/
83 static void w9968cf_write_sb(struct sd *sd, u16 value)
84 {
85 	int ret;
86 
87 	if (sd->gspca_dev.usb_err < 0)
88 		return;
89 
90 	/* Avoid things going to fast for the bridge with a xhci host */
91 	udelay(150);
92 
93 	/* We don't use reg_w here, as that would cause all writes when
94 	   bitbanging i2c to be logged, making the logs impossible to read */
95 	ret = usb_control_msg(sd->gspca_dev.dev,
96 		usb_sndctrlpipe(sd->gspca_dev.dev, 0),
97 		0,
98 		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
99 		value, 0x01, NULL, 0, 500);
100 
101 	udelay(W9968CF_I2C_BUS_DELAY);
102 
103 	if (ret < 0) {
104 		pr_err("Write SB reg [01] %04x failed\n", value);
105 		sd->gspca_dev.usb_err = ret;
106 	}
107 }
108 
109 /*--------------------------------------------------------------------------
110   Read data from the serial bus control register.
111   Return 0 on success, a negative number otherwise.
112   --------------------------------------------------------------------------*/
113 static int w9968cf_read_sb(struct sd *sd)
114 {
115 	int ret;
116 
117 	if (sd->gspca_dev.usb_err < 0)
118 		return -1;
119 
120 	/* Avoid things going to fast for the bridge with a xhci host */
121 	udelay(150);
122 
123 	/* We don't use reg_r here, as the w9968cf is special and has 16
124 	   bit registers instead of 8 bit */
125 	ret = usb_control_msg(sd->gspca_dev.dev,
126 			usb_rcvctrlpipe(sd->gspca_dev.dev, 0),
127 			1,
128 			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
129 			0, 0x01, sd->gspca_dev.usb_buf, 2, 500);
130 	if (ret >= 0) {
131 		ret = sd->gspca_dev.usb_buf[0] |
132 		      (sd->gspca_dev.usb_buf[1] << 8);
133 	} else {
134 		pr_err("Read SB reg [01] failed\n");
135 		sd->gspca_dev.usb_err = ret;
136 		/*
137 		 * Make sure the buffer is zeroed to avoid uninitialized
138 		 * values.
139 		 */
140 		memset(sd->gspca_dev.usb_buf, 0, 2);
141 	}
142 
143 	udelay(W9968CF_I2C_BUS_DELAY);
144 
145 	return ret;
146 }
147 
148 /*--------------------------------------------------------------------------
149   Upload quantization tables for the JPEG compression.
150   This function is called by w9968cf_start_transfer().
151   Return 0 on success, a negative number otherwise.
152   --------------------------------------------------------------------------*/
153 static void w9968cf_upload_quantizationtables(struct sd *sd)
154 {
155 	u16 a, b;
156 	int i, j;
157 
158 	reg_w(sd, 0x39, 0x0010); /* JPEG clock enable */
159 
160 	for (i = 0, j = 0; i < 32; i++, j += 2) {
161 		a = Y_QUANTABLE[j] | ((unsigned)(Y_QUANTABLE[j + 1]) << 8);
162 		b = UV_QUANTABLE[j] | ((unsigned)(UV_QUANTABLE[j + 1]) << 8);
163 		reg_w(sd, 0x40 + i, a);
164 		reg_w(sd, 0x60 + i, b);
165 	}
166 	reg_w(sd, 0x39, 0x0012); /* JPEG encoder enable */
167 }
168 
169 /****************************************************************************
170  * Low-level I2C I/O functions.                                             *
171  * The adapter supports the following I2C transfer functions:               *
172  * i2c_adap_fastwrite_byte_data() (at 400 kHz bit frequency only)           *
173  * i2c_adap_read_byte_data()                                                *
174  * i2c_adap_read_byte()                                                     *
175  ****************************************************************************/
176 
177 static void w9968cf_smbus_start(struct sd *sd)
178 {
179 	w9968cf_write_sb(sd, 0x0011); /* SDE=1, SDA=0, SCL=1 */
180 	w9968cf_write_sb(sd, 0x0010); /* SDE=1, SDA=0, SCL=0 */
181 }
182 
183 static void w9968cf_smbus_stop(struct sd *sd)
184 {
185 	w9968cf_write_sb(sd, 0x0010); /* SDE=1, SDA=0, SCL=0 */
186 	w9968cf_write_sb(sd, 0x0011); /* SDE=1, SDA=0, SCL=1 */
187 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
188 }
189 
190 static void w9968cf_smbus_write_byte(struct sd *sd, u8 v)
191 {
192 	u8 bit;
193 	int sda;
194 
195 	for (bit = 0 ; bit < 8 ; bit++) {
196 		sda = (v & 0x80) ? 2 : 0;
197 		v <<= 1;
198 		/* SDE=1, SDA=sda, SCL=0 */
199 		w9968cf_write_sb(sd, 0x10 | sda);
200 		/* SDE=1, SDA=sda, SCL=1 */
201 		w9968cf_write_sb(sd, 0x11 | sda);
202 		/* SDE=1, SDA=sda, SCL=0 */
203 		w9968cf_write_sb(sd, 0x10 | sda);
204 	}
205 }
206 
207 static void w9968cf_smbus_read_byte(struct sd *sd, u8 *v)
208 {
209 	u8 bit;
210 
211 	/* No need to ensure SDA is high as we are always called after
212 	   read_ack which ends with SDA high */
213 	*v = 0;
214 	for (bit = 0 ; bit < 8 ; bit++) {
215 		*v <<= 1;
216 		/* SDE=1, SDA=1, SCL=1 */
217 		w9968cf_write_sb(sd, 0x0013);
218 		*v |= (w9968cf_read_sb(sd) & 0x0008) ? 1 : 0;
219 		/* SDE=1, SDA=1, SCL=0 */
220 		w9968cf_write_sb(sd, 0x0012);
221 	}
222 }
223 
224 static void w9968cf_smbus_write_nack(struct sd *sd)
225 {
226 	/* No need to ensure SDA is high as we are always called after
227 	   read_byte which ends with SDA high */
228 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
229 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
230 }
231 
232 static void w9968cf_smbus_read_ack(struct sd *sd)
233 {
234 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
235 	int sda;
236 
237 	/* Ensure SDA is high before raising clock to avoid a spurious stop */
238 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
239 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
240 	sda = w9968cf_read_sb(sd);
241 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
242 	if (sda >= 0 && (sda & 0x08)) {
243 		gspca_dbg(gspca_dev, D_USBI, "Did not receive i2c ACK\n");
244 		sd->gspca_dev.usb_err = -EIO;
245 	}
246 }
247 
248 /* SMBus protocol: S Addr Wr [A] Subaddr [A] Value [A] P */
249 static void w9968cf_i2c_w(struct sd *sd, u8 reg, u8 value)
250 {
251 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
252 	u16* data = (u16 *)sd->gspca_dev.usb_buf;
253 
254 	data[0] = 0x082f | ((sd->sensor_addr & 0x80) ? 0x1500 : 0x0);
255 	data[0] |= (sd->sensor_addr & 0x40) ? 0x4000 : 0x0;
256 	data[1] = 0x2082 | ((sd->sensor_addr & 0x40) ? 0x0005 : 0x0);
257 	data[1] |= (sd->sensor_addr & 0x20) ? 0x0150 : 0x0;
258 	data[1] |= (sd->sensor_addr & 0x10) ? 0x5400 : 0x0;
259 	data[2] = 0x8208 | ((sd->sensor_addr & 0x08) ? 0x0015 : 0x0);
260 	data[2] |= (sd->sensor_addr & 0x04) ? 0x0540 : 0x0;
261 	data[2] |= (sd->sensor_addr & 0x02) ? 0x5000 : 0x0;
262 	data[3] = 0x1d20 | ((sd->sensor_addr & 0x02) ? 0x0001 : 0x0);
263 	data[3] |= (sd->sensor_addr & 0x01) ? 0x0054 : 0x0;
264 
265 	w9968cf_write_fsb(sd, data);
266 
267 	data[0] = 0x8208 | ((reg & 0x80) ? 0x0015 : 0x0);
268 	data[0] |= (reg & 0x40) ? 0x0540 : 0x0;
269 	data[0] |= (reg & 0x20) ? 0x5000 : 0x0;
270 	data[1] = 0x0820 | ((reg & 0x20) ? 0x0001 : 0x0);
271 	data[1] |= (reg & 0x10) ? 0x0054 : 0x0;
272 	data[1] |= (reg & 0x08) ? 0x1500 : 0x0;
273 	data[1] |= (reg & 0x04) ? 0x4000 : 0x0;
274 	data[2] = 0x2082 | ((reg & 0x04) ? 0x0005 : 0x0);
275 	data[2] |= (reg & 0x02) ? 0x0150 : 0x0;
276 	data[2] |= (reg & 0x01) ? 0x5400 : 0x0;
277 	data[3] = 0x001d;
278 
279 	w9968cf_write_fsb(sd, data);
280 
281 	data[0] = 0x8208 | ((value & 0x80) ? 0x0015 : 0x0);
282 	data[0] |= (value & 0x40) ? 0x0540 : 0x0;
283 	data[0] |= (value & 0x20) ? 0x5000 : 0x0;
284 	data[1] = 0x0820 | ((value & 0x20) ? 0x0001 : 0x0);
285 	data[1] |= (value & 0x10) ? 0x0054 : 0x0;
286 	data[1] |= (value & 0x08) ? 0x1500 : 0x0;
287 	data[1] |= (value & 0x04) ? 0x4000 : 0x0;
288 	data[2] = 0x2082 | ((value & 0x04) ? 0x0005 : 0x0);
289 	data[2] |= (value & 0x02) ? 0x0150 : 0x0;
290 	data[2] |= (value & 0x01) ? 0x5400 : 0x0;
291 	data[3] = 0xfe1d;
292 
293 	w9968cf_write_fsb(sd, data);
294 
295 	gspca_dbg(gspca_dev, D_USBO, "i2c 0x%02x -> [0x%02x]\n", value, reg);
296 }
297 
298 /* SMBus protocol: S Addr Wr [A] Subaddr [A] P S Addr+1 Rd [A] [Value] NA P */
299 static int w9968cf_i2c_r(struct sd *sd, u8 reg)
300 {
301 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
302 	int ret = 0;
303 	u8 value;
304 
305 	/* Fast serial bus data control disable */
306 	w9968cf_write_sb(sd, 0x0013); /* don't change ! */
307 
308 	w9968cf_smbus_start(sd);
309 	w9968cf_smbus_write_byte(sd, sd->sensor_addr);
310 	w9968cf_smbus_read_ack(sd);
311 	w9968cf_smbus_write_byte(sd, reg);
312 	w9968cf_smbus_read_ack(sd);
313 	w9968cf_smbus_stop(sd);
314 	w9968cf_smbus_start(sd);
315 	w9968cf_smbus_write_byte(sd, sd->sensor_addr + 1);
316 	w9968cf_smbus_read_ack(sd);
317 	w9968cf_smbus_read_byte(sd, &value);
318 	/* signal we don't want to read anymore, the v4l1 driver used to
319 	   send an ack here which is very wrong! (and then fixed
320 	   the issues this gave by retrying reads) */
321 	w9968cf_smbus_write_nack(sd);
322 	w9968cf_smbus_stop(sd);
323 
324 	/* Fast serial bus data control re-enable */
325 	w9968cf_write_sb(sd, 0x0030);
326 
327 	if (sd->gspca_dev.usb_err >= 0) {
328 		ret = value;
329 		gspca_dbg(gspca_dev, D_USBI, "i2c [0x%02X] -> 0x%02X\n",
330 			  reg, value);
331 	} else
332 		gspca_err(gspca_dev, "i2c read [0x%02x] failed\n", reg);
333 
334 	return ret;
335 }
336 
337 /*--------------------------------------------------------------------------
338   Turn on the LED on some webcams. A beep should be heard too.
339   Return 0 on success, a negative number otherwise.
340   --------------------------------------------------------------------------*/
341 static void w9968cf_configure(struct sd *sd)
342 {
343 	reg_w(sd, 0x00, 0xff00); /* power-down */
344 	reg_w(sd, 0x00, 0xbf17); /* reset everything */
345 	reg_w(sd, 0x00, 0xbf10); /* normal operation */
346 	reg_w(sd, 0x01, 0x0010); /* serial bus, SDS high */
347 	reg_w(sd, 0x01, 0x0000); /* serial bus, SDS low */
348 	reg_w(sd, 0x01, 0x0010); /* ..high 'beep-beep' */
349 	reg_w(sd, 0x01, 0x0030); /* Set sda scl to FSB mode */
350 
351 	sd->stopped = 1;
352 }
353 
354 static void w9968cf_init(struct sd *sd)
355 {
356 	unsigned long hw_bufsize = sd->sif ? (352 * 288 * 2) : (640 * 480 * 2),
357 		      y0 = 0x0000,
358 		      u0 = y0 + hw_bufsize / 2,
359 		      v0 = u0 + hw_bufsize / 4,
360 		      y1 = v0 + hw_bufsize / 4,
361 		      u1 = y1 + hw_bufsize / 2,
362 		      v1 = u1 + hw_bufsize / 4;
363 
364 	reg_w(sd, 0x00, 0xff00); /* power off */
365 	reg_w(sd, 0x00, 0xbf10); /* power on */
366 
367 	reg_w(sd, 0x03, 0x405d); /* DRAM timings */
368 	reg_w(sd, 0x04, 0x0030); /* SDRAM timings */
369 
370 	reg_w(sd, 0x20, y0 & 0xffff); /* Y buf.0, low */
371 	reg_w(sd, 0x21, y0 >> 16);    /* Y buf.0, high */
372 	reg_w(sd, 0x24, u0 & 0xffff); /* U buf.0, low */
373 	reg_w(sd, 0x25, u0 >> 16);    /* U buf.0, high */
374 	reg_w(sd, 0x28, v0 & 0xffff); /* V buf.0, low */
375 	reg_w(sd, 0x29, v0 >> 16);    /* V buf.0, high */
376 
377 	reg_w(sd, 0x22, y1 & 0xffff); /* Y buf.1, low */
378 	reg_w(sd, 0x23, y1 >> 16);    /* Y buf.1, high */
379 	reg_w(sd, 0x26, u1 & 0xffff); /* U buf.1, low */
380 	reg_w(sd, 0x27, u1 >> 16);    /* U buf.1, high */
381 	reg_w(sd, 0x2a, v1 & 0xffff); /* V buf.1, low */
382 	reg_w(sd, 0x2b, v1 >> 16);    /* V buf.1, high */
383 
384 	reg_w(sd, 0x32, y1 & 0xffff); /* JPEG buf 0 low */
385 	reg_w(sd, 0x33, y1 >> 16);    /* JPEG buf 0 high */
386 
387 	reg_w(sd, 0x34, y1 & 0xffff); /* JPEG buf 1 low */
388 	reg_w(sd, 0x35, y1 >> 16);    /* JPEG bug 1 high */
389 
390 	reg_w(sd, 0x36, 0x0000);/* JPEG restart interval */
391 	reg_w(sd, 0x37, 0x0804);/*JPEG VLE FIFO threshold*/
392 	reg_w(sd, 0x38, 0x0000);/* disable hw up-scaling */
393 	reg_w(sd, 0x3f, 0x0000); /* JPEG/MCTL test data */
394 }
395 
396 static void w9968cf_set_crop_window(struct sd *sd)
397 {
398 	int start_cropx, start_cropy,  x, y, fw, fh, cw, ch,
399 	    max_width, max_height;
400 
401 	if (sd->sif) {
402 		max_width  = 352;
403 		max_height = 288;
404 	} else {
405 		max_width  = 640;
406 		max_height = 480;
407 	}
408 
409 	if (sd->sensor == SEN_OV7620) {
410 		/*
411 		 * Sigh, this is dependend on the clock / framerate changes
412 		 * made by the frequency control, sick.
413 		 *
414 		 * Note we cannot use v4l2_ctrl_g_ctrl here, as we get called
415 		 * from ov519.c:setfreq() with the ctrl lock held!
416 		 */
417 		if (sd->freq->val == 1) {
418 			start_cropx = 277;
419 			start_cropy = 37;
420 		} else {
421 			start_cropx = 105;
422 			start_cropy = 37;
423 		}
424 	} else {
425 		start_cropx = 320;
426 		start_cropy = 35;
427 	}
428 
429 	/* Work around to avoid FP arithmetic */
430 	#define SC(x) ((x) << 10)
431 
432 	/* Scaling factors */
433 	fw = SC(sd->gspca_dev.pixfmt.width) / max_width;
434 	fh = SC(sd->gspca_dev.pixfmt.height) / max_height;
435 
436 	cw = (fw >= fh) ? max_width : SC(sd->gspca_dev.pixfmt.width) / fh;
437 	ch = (fw >= fh) ? SC(sd->gspca_dev.pixfmt.height) / fw : max_height;
438 
439 	sd->sensor_width = max_width;
440 	sd->sensor_height = max_height;
441 
442 	x = (max_width - cw) / 2;
443 	y = (max_height - ch) / 2;
444 
445 	reg_w(sd, 0x10, start_cropx + x);
446 	reg_w(sd, 0x11, start_cropy + y);
447 	reg_w(sd, 0x12, start_cropx + x + cw);
448 	reg_w(sd, 0x13, start_cropy + y + ch);
449 }
450 
451 static void w9968cf_mode_init_regs(struct sd *sd)
452 {
453 	int val, vs_polarity, hs_polarity;
454 
455 	w9968cf_set_crop_window(sd);
456 
457 	reg_w(sd, 0x14, sd->gspca_dev.pixfmt.width);
458 	reg_w(sd, 0x15, sd->gspca_dev.pixfmt.height);
459 
460 	/* JPEG width & height */
461 	reg_w(sd, 0x30, sd->gspca_dev.pixfmt.width);
462 	reg_w(sd, 0x31, sd->gspca_dev.pixfmt.height);
463 
464 	/* Y & UV frame buffer strides (in WORD) */
465 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
466 	    V4L2_PIX_FMT_JPEG) {
467 		reg_w(sd, 0x2c, sd->gspca_dev.pixfmt.width / 2);
468 		reg_w(sd, 0x2d, sd->gspca_dev.pixfmt.width / 4);
469 	} else
470 		reg_w(sd, 0x2c, sd->gspca_dev.pixfmt.width);
471 
472 	reg_w(sd, 0x00, 0xbf17); /* reset everything */
473 	reg_w(sd, 0x00, 0xbf10); /* normal operation */
474 
475 	/* Transfer size in WORDS (for UYVY format only) */
476 	val = sd->gspca_dev.pixfmt.width * sd->gspca_dev.pixfmt.height;
477 	reg_w(sd, 0x3d, val & 0xffff); /* low bits */
478 	reg_w(sd, 0x3e, val >> 16);    /* high bits */
479 
480 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
481 	    V4L2_PIX_FMT_JPEG) {
482 		/* We may get called multiple times (usb isoc bw negotiat.) */
483 		jpeg_define(sd->jpeg_hdr, sd->gspca_dev.pixfmt.height,
484 			    sd->gspca_dev.pixfmt.width, 0x22); /* JPEG 420 */
485 		jpeg_set_qual(sd->jpeg_hdr, v4l2_ctrl_g_ctrl(sd->jpegqual));
486 		w9968cf_upload_quantizationtables(sd);
487 		v4l2_ctrl_grab(sd->jpegqual, true);
488 	}
489 
490 	/* Video Capture Control Register */
491 	if (sd->sensor == SEN_OV7620) {
492 		/* Seems to work around a bug in the image sensor */
493 		vs_polarity = 1;
494 		hs_polarity = 1;
495 	} else {
496 		vs_polarity = 1;
497 		hs_polarity = 0;
498 	}
499 
500 	val = (vs_polarity << 12) | (hs_polarity << 11);
501 
502 	/* NOTE: We may not have enough memory to do double buffering while
503 	   doing compression (amount of memory differs per model cam).
504 	   So we use the second image buffer also as jpeg stream buffer
505 	   (see w9968cf_init), and disable double buffering. */
506 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
507 	    V4L2_PIX_FMT_JPEG) {
508 		/* val |= 0x0002; YUV422P */
509 		val |= 0x0003; /* YUV420P */
510 	} else
511 		val |= 0x0080; /* Enable HW double buffering */
512 
513 	/* val |= 0x0020; enable clamping */
514 	/* val |= 0x0008; enable (1-2-1) filter */
515 	/* val |= 0x000c; enable (2-3-6-3-2) filter */
516 
517 	val |= 0x8000; /* capt. enable */
518 
519 	reg_w(sd, 0x16, val);
520 
521 	sd->gspca_dev.empty_packet = 0;
522 }
523 
524 static void w9968cf_stop0(struct sd *sd)
525 {
526 	v4l2_ctrl_grab(sd->jpegqual, false);
527 	reg_w(sd, 0x39, 0x0000); /* disable JPEG encoder */
528 	reg_w(sd, 0x16, 0x0000); /* stop video capture */
529 }
530 
531 /* The w9968cf docs say that a 0 sized packet means EOF (and also SOF
532    for the next frame). This seems to simply not be true when operating
533    in JPEG mode, in this case there may be empty packets within the
534    frame. So in JPEG mode use the JPEG SOI marker to detect SOF.
535 
536    Note to make things even more interesting the w9968cf sends *PLANAR* jpeg,
537    to be precise it sends: SOI, SOF, DRI, SOS, Y-data, SOS, U-data, SOS,
538    V-data, EOI. */
539 static void w9968cf_pkt_scan(struct gspca_dev *gspca_dev,
540 			u8 *data,			/* isoc packet */
541 			int len)			/* iso packet length */
542 {
543 	struct sd *sd = (struct sd *) gspca_dev;
544 
545 	if (w9968cf_vga_mode[gspca_dev->curr_mode].pixelformat ==
546 	    V4L2_PIX_FMT_JPEG) {
547 		if (len >= 2 &&
548 		    data[0] == 0xff &&
549 		    data[1] == 0xd8) {
550 			gspca_frame_add(gspca_dev, LAST_PACKET,
551 					NULL, 0);
552 			gspca_frame_add(gspca_dev, FIRST_PACKET,
553 					sd->jpeg_hdr, JPEG_HDR_SZ);
554 			/* Strip the ff d8, our own header (which adds
555 			   huffman and quantization tables) already has this */
556 			len -= 2;
557 			data += 2;
558 		}
559 	} else {
560 		/* In UYVY mode an empty packet signals EOF */
561 		if (gspca_dev->empty_packet) {
562 			gspca_frame_add(gspca_dev, LAST_PACKET,
563 						NULL, 0);
564 			gspca_frame_add(gspca_dev, FIRST_PACKET,
565 					NULL, 0);
566 			gspca_dev->empty_packet = 0;
567 		}
568 	}
569 	gspca_frame_add(gspca_dev, INTER_PACKET, data, len);
570 }
571