xref: /openbmc/linux/drivers/media/usb/gspca/w996Xcf.c (revision da1d9caf)
1 // SPDX-License-Identifier: GPL-2.0-or-later
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 
12 /* Note this is not a stand alone driver, it gets included in ov519.c, this
13    is a bit of a hack, but it needs the driver code for a lot of different
14    ov sensors which is already present in ov519.c (the old v4l1 driver used
15    the ovchipcam framework). When we have the time we really should move
16    the sensor drivers to v4l2 sub drivers, and properly split of this
17    driver from ov519.c */
18 
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20 
21 #define W9968CF_I2C_BUS_DELAY    4 /* delay in us for I2C bit r/w operations */
22 
23 #define Y_QUANTABLE (&sd->jpeg_hdr[JPEG_QT0_OFFSET])
24 #define UV_QUANTABLE (&sd->jpeg_hdr[JPEG_QT1_OFFSET])
25 
26 static const struct v4l2_pix_format w9968cf_vga_mode[] = {
27 	{160, 120, V4L2_PIX_FMT_UYVY, V4L2_FIELD_NONE,
28 		.bytesperline = 160 * 2,
29 		.sizeimage = 160 * 120 * 2,
30 		.colorspace = V4L2_COLORSPACE_JPEG},
31 	{176, 144, V4L2_PIX_FMT_UYVY, V4L2_FIELD_NONE,
32 		.bytesperline = 176 * 2,
33 		.sizeimage = 176 * 144 * 2,
34 		.colorspace = V4L2_COLORSPACE_JPEG},
35 	{320, 240, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
36 		.bytesperline = 320 * 2,
37 		.sizeimage = 320 * 240 * 2,
38 		.colorspace = V4L2_COLORSPACE_JPEG},
39 	{352, 288, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
40 		.bytesperline = 352 * 2,
41 		.sizeimage = 352 * 288 * 2,
42 		.colorspace = V4L2_COLORSPACE_JPEG},
43 	{640, 480, V4L2_PIX_FMT_JPEG, V4L2_FIELD_NONE,
44 		.bytesperline = 640 * 2,
45 		.sizeimage = 640 * 480 * 2,
46 		.colorspace = V4L2_COLORSPACE_JPEG},
47 };
48 
49 static void reg_w(struct sd *sd, u16 index, u16 value);
50 
51 /*--------------------------------------------------------------------------
52   Write 64-bit data to the fast serial bus registers.
53   Return 0 on success, -1 otherwise.
54   --------------------------------------------------------------------------*/
55 static void w9968cf_write_fsb(struct sd *sd, u16* data)
56 {
57 	struct usb_device *udev = sd->gspca_dev.dev;
58 	u16 value;
59 	int ret;
60 
61 	if (sd->gspca_dev.usb_err < 0)
62 		return;
63 
64 	value = *data++;
65 	memcpy(sd->gspca_dev.usb_buf, data, 6);
66 
67 	/* Avoid things going to fast for the bridge with a xhci host */
68 	udelay(150);
69 	ret = usb_control_msg(udev, usb_sndctrlpipe(udev, 0), 0,
70 			      USB_TYPE_VENDOR | USB_DIR_OUT | USB_RECIP_DEVICE,
71 			      value, 0x06, sd->gspca_dev.usb_buf, 6, 500);
72 	if (ret < 0) {
73 		pr_err("Write FSB registers failed (%d)\n", ret);
74 		sd->gspca_dev.usb_err = ret;
75 	}
76 }
77 
78 /*--------------------------------------------------------------------------
79   Write data to the serial bus control register.
80   Return 0 on success, a negative number otherwise.
81   --------------------------------------------------------------------------*/
82 static void w9968cf_write_sb(struct sd *sd, u16 value)
83 {
84 	int ret;
85 
86 	if (sd->gspca_dev.usb_err < 0)
87 		return;
88 
89 	/* Avoid things going to fast for the bridge with a xhci host */
90 	udelay(150);
91 
92 	/* We don't use reg_w here, as that would cause all writes when
93 	   bitbanging i2c to be logged, making the logs impossible to read */
94 	ret = usb_control_msg(sd->gspca_dev.dev,
95 		usb_sndctrlpipe(sd->gspca_dev.dev, 0),
96 		0,
97 		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
98 		value, 0x01, NULL, 0, 500);
99 
100 	udelay(W9968CF_I2C_BUS_DELAY);
101 
102 	if (ret < 0) {
103 		pr_err("Write SB reg [01] %04x failed\n", value);
104 		sd->gspca_dev.usb_err = ret;
105 	}
106 }
107 
108 /*--------------------------------------------------------------------------
109   Read data from the serial bus control register.
110   Return 0 on success, a negative number otherwise.
111   --------------------------------------------------------------------------*/
112 static int w9968cf_read_sb(struct sd *sd)
113 {
114 	int ret;
115 
116 	if (sd->gspca_dev.usb_err < 0)
117 		return -1;
118 
119 	/* Avoid things going to fast for the bridge with a xhci host */
120 	udelay(150);
121 
122 	/* We don't use reg_r here, as the w9968cf is special and has 16
123 	   bit registers instead of 8 bit */
124 	ret = usb_control_msg(sd->gspca_dev.dev,
125 			usb_rcvctrlpipe(sd->gspca_dev.dev, 0),
126 			1,
127 			USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
128 			0, 0x01, sd->gspca_dev.usb_buf, 2, 500);
129 	if (ret >= 0) {
130 		ret = sd->gspca_dev.usb_buf[0] |
131 		      (sd->gspca_dev.usb_buf[1] << 8);
132 	} else {
133 		pr_err("Read SB reg [01] failed\n");
134 		sd->gspca_dev.usb_err = ret;
135 		/*
136 		 * Make sure the buffer is zeroed to avoid uninitialized
137 		 * values.
138 		 */
139 		memset(sd->gspca_dev.usb_buf, 0, 2);
140 	}
141 
142 	udelay(W9968CF_I2C_BUS_DELAY);
143 
144 	return ret;
145 }
146 
147 /*--------------------------------------------------------------------------
148   Upload quantization tables for the JPEG compression.
149   This function is called by w9968cf_start_transfer().
150   Return 0 on success, a negative number otherwise.
151   --------------------------------------------------------------------------*/
152 static void w9968cf_upload_quantizationtables(struct sd *sd)
153 {
154 	u16 a, b;
155 	int i, j;
156 
157 	reg_w(sd, 0x39, 0x0010); /* JPEG clock enable */
158 
159 	for (i = 0, j = 0; i < 32; i++, j += 2) {
160 		a = Y_QUANTABLE[j] | ((unsigned)(Y_QUANTABLE[j + 1]) << 8);
161 		b = UV_QUANTABLE[j] | ((unsigned)(UV_QUANTABLE[j + 1]) << 8);
162 		reg_w(sd, 0x40 + i, a);
163 		reg_w(sd, 0x60 + i, b);
164 	}
165 	reg_w(sd, 0x39, 0x0012); /* JPEG encoder enable */
166 }
167 
168 /****************************************************************************
169  * Low-level I2C I/O functions.                                             *
170  * The adapter supports the following I2C transfer functions:               *
171  * i2c_adap_fastwrite_byte_data() (at 400 kHz bit frequency only)           *
172  * i2c_adap_read_byte_data()                                                *
173  * i2c_adap_read_byte()                                                     *
174  ****************************************************************************/
175 
176 static void w9968cf_smbus_start(struct sd *sd)
177 {
178 	w9968cf_write_sb(sd, 0x0011); /* SDE=1, SDA=0, SCL=1 */
179 	w9968cf_write_sb(sd, 0x0010); /* SDE=1, SDA=0, SCL=0 */
180 }
181 
182 static void w9968cf_smbus_stop(struct sd *sd)
183 {
184 	w9968cf_write_sb(sd, 0x0010); /* SDE=1, SDA=0, SCL=0 */
185 	w9968cf_write_sb(sd, 0x0011); /* SDE=1, SDA=0, SCL=1 */
186 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
187 }
188 
189 static void w9968cf_smbus_write_byte(struct sd *sd, u8 v)
190 {
191 	u8 bit;
192 	int sda;
193 
194 	for (bit = 0 ; bit < 8 ; bit++) {
195 		sda = (v & 0x80) ? 2 : 0;
196 		v <<= 1;
197 		/* SDE=1, SDA=sda, SCL=0 */
198 		w9968cf_write_sb(sd, 0x10 | sda);
199 		/* SDE=1, SDA=sda, SCL=1 */
200 		w9968cf_write_sb(sd, 0x11 | sda);
201 		/* SDE=1, SDA=sda, SCL=0 */
202 		w9968cf_write_sb(sd, 0x10 | sda);
203 	}
204 }
205 
206 static void w9968cf_smbus_read_byte(struct sd *sd, u8 *v)
207 {
208 	u8 bit;
209 
210 	/* No need to ensure SDA is high as we are always called after
211 	   read_ack which ends with SDA high */
212 	*v = 0;
213 	for (bit = 0 ; bit < 8 ; bit++) {
214 		*v <<= 1;
215 		/* SDE=1, SDA=1, SCL=1 */
216 		w9968cf_write_sb(sd, 0x0013);
217 		*v |= (w9968cf_read_sb(sd) & 0x0008) ? 1 : 0;
218 		/* SDE=1, SDA=1, SCL=0 */
219 		w9968cf_write_sb(sd, 0x0012);
220 	}
221 }
222 
223 static void w9968cf_smbus_write_nack(struct sd *sd)
224 {
225 	/* No need to ensure SDA is high as we are always called after
226 	   read_byte which ends with SDA high */
227 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
228 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
229 }
230 
231 static void w9968cf_smbus_read_ack(struct sd *sd)
232 {
233 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
234 	int sda;
235 
236 	/* Ensure SDA is high before raising clock to avoid a spurious stop */
237 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
238 	w9968cf_write_sb(sd, 0x0013); /* SDE=1, SDA=1, SCL=1 */
239 	sda = w9968cf_read_sb(sd);
240 	w9968cf_write_sb(sd, 0x0012); /* SDE=1, SDA=1, SCL=0 */
241 	if (sda >= 0 && (sda & 0x08)) {
242 		gspca_dbg(gspca_dev, D_USBI, "Did not receive i2c ACK\n");
243 		sd->gspca_dev.usb_err = -EIO;
244 	}
245 }
246 
247 /* SMBus protocol: S Addr Wr [A] Subaddr [A] Value [A] P */
248 static void w9968cf_i2c_w(struct sd *sd, u8 reg, u8 value)
249 {
250 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
251 	u16* data = (u16 *)sd->gspca_dev.usb_buf;
252 
253 	data[0] = 0x082f | ((sd->sensor_addr & 0x80) ? 0x1500 : 0x0);
254 	data[0] |= (sd->sensor_addr & 0x40) ? 0x4000 : 0x0;
255 	data[1] = 0x2082 | ((sd->sensor_addr & 0x40) ? 0x0005 : 0x0);
256 	data[1] |= (sd->sensor_addr & 0x20) ? 0x0150 : 0x0;
257 	data[1] |= (sd->sensor_addr & 0x10) ? 0x5400 : 0x0;
258 	data[2] = 0x8208 | ((sd->sensor_addr & 0x08) ? 0x0015 : 0x0);
259 	data[2] |= (sd->sensor_addr & 0x04) ? 0x0540 : 0x0;
260 	data[2] |= (sd->sensor_addr & 0x02) ? 0x5000 : 0x0;
261 	data[3] = 0x1d20 | ((sd->sensor_addr & 0x02) ? 0x0001 : 0x0);
262 	data[3] |= (sd->sensor_addr & 0x01) ? 0x0054 : 0x0;
263 
264 	w9968cf_write_fsb(sd, data);
265 
266 	data[0] = 0x8208 | ((reg & 0x80) ? 0x0015 : 0x0);
267 	data[0] |= (reg & 0x40) ? 0x0540 : 0x0;
268 	data[0] |= (reg & 0x20) ? 0x5000 : 0x0;
269 	data[1] = 0x0820 | ((reg & 0x20) ? 0x0001 : 0x0);
270 	data[1] |= (reg & 0x10) ? 0x0054 : 0x0;
271 	data[1] |= (reg & 0x08) ? 0x1500 : 0x0;
272 	data[1] |= (reg & 0x04) ? 0x4000 : 0x0;
273 	data[2] = 0x2082 | ((reg & 0x04) ? 0x0005 : 0x0);
274 	data[2] |= (reg & 0x02) ? 0x0150 : 0x0;
275 	data[2] |= (reg & 0x01) ? 0x5400 : 0x0;
276 	data[3] = 0x001d;
277 
278 	w9968cf_write_fsb(sd, data);
279 
280 	data[0] = 0x8208 | ((value & 0x80) ? 0x0015 : 0x0);
281 	data[0] |= (value & 0x40) ? 0x0540 : 0x0;
282 	data[0] |= (value & 0x20) ? 0x5000 : 0x0;
283 	data[1] = 0x0820 | ((value & 0x20) ? 0x0001 : 0x0);
284 	data[1] |= (value & 0x10) ? 0x0054 : 0x0;
285 	data[1] |= (value & 0x08) ? 0x1500 : 0x0;
286 	data[1] |= (value & 0x04) ? 0x4000 : 0x0;
287 	data[2] = 0x2082 | ((value & 0x04) ? 0x0005 : 0x0);
288 	data[2] |= (value & 0x02) ? 0x0150 : 0x0;
289 	data[2] |= (value & 0x01) ? 0x5400 : 0x0;
290 	data[3] = 0xfe1d;
291 
292 	w9968cf_write_fsb(sd, data);
293 
294 	gspca_dbg(gspca_dev, D_USBO, "i2c 0x%02x -> [0x%02x]\n", value, reg);
295 }
296 
297 /* SMBus protocol: S Addr Wr [A] Subaddr [A] P S Addr+1 Rd [A] [Value] NA P */
298 static int w9968cf_i2c_r(struct sd *sd, u8 reg)
299 {
300 	struct gspca_dev *gspca_dev = (struct gspca_dev *)sd;
301 	int ret = 0;
302 	u8 value;
303 
304 	/* Fast serial bus data control disable */
305 	w9968cf_write_sb(sd, 0x0013); /* don't change ! */
306 
307 	w9968cf_smbus_start(sd);
308 	w9968cf_smbus_write_byte(sd, sd->sensor_addr);
309 	w9968cf_smbus_read_ack(sd);
310 	w9968cf_smbus_write_byte(sd, reg);
311 	w9968cf_smbus_read_ack(sd);
312 	w9968cf_smbus_stop(sd);
313 	w9968cf_smbus_start(sd);
314 	w9968cf_smbus_write_byte(sd, sd->sensor_addr + 1);
315 	w9968cf_smbus_read_ack(sd);
316 	w9968cf_smbus_read_byte(sd, &value);
317 	/* signal we don't want to read anymore, the v4l1 driver used to
318 	   send an ack here which is very wrong! (and then fixed
319 	   the issues this gave by retrying reads) */
320 	w9968cf_smbus_write_nack(sd);
321 	w9968cf_smbus_stop(sd);
322 
323 	/* Fast serial bus data control re-enable */
324 	w9968cf_write_sb(sd, 0x0030);
325 
326 	if (sd->gspca_dev.usb_err >= 0) {
327 		ret = value;
328 		gspca_dbg(gspca_dev, D_USBI, "i2c [0x%02X] -> 0x%02X\n",
329 			  reg, value);
330 	} else
331 		gspca_err(gspca_dev, "i2c read [0x%02x] failed\n", reg);
332 
333 	return ret;
334 }
335 
336 /*--------------------------------------------------------------------------
337   Turn on the LED on some webcams. A beep should be heard too.
338   Return 0 on success, a negative number otherwise.
339   --------------------------------------------------------------------------*/
340 static void w9968cf_configure(struct sd *sd)
341 {
342 	reg_w(sd, 0x00, 0xff00); /* power-down */
343 	reg_w(sd, 0x00, 0xbf17); /* reset everything */
344 	reg_w(sd, 0x00, 0xbf10); /* normal operation */
345 	reg_w(sd, 0x01, 0x0010); /* serial bus, SDS high */
346 	reg_w(sd, 0x01, 0x0000); /* serial bus, SDS low */
347 	reg_w(sd, 0x01, 0x0010); /* ..high 'beep-beep' */
348 	reg_w(sd, 0x01, 0x0030); /* Set sda scl to FSB mode */
349 
350 	sd->stopped = 1;
351 }
352 
353 static void w9968cf_init(struct sd *sd)
354 {
355 	unsigned long hw_bufsize = sd->sif ? (352 * 288 * 2) : (640 * 480 * 2),
356 		      y0 = 0x0000,
357 		      u0 = y0 + hw_bufsize / 2,
358 		      v0 = u0 + hw_bufsize / 4,
359 		      y1 = v0 + hw_bufsize / 4,
360 		      u1 = y1 + hw_bufsize / 2,
361 		      v1 = u1 + hw_bufsize / 4;
362 
363 	reg_w(sd, 0x00, 0xff00); /* power off */
364 	reg_w(sd, 0x00, 0xbf10); /* power on */
365 
366 	reg_w(sd, 0x03, 0x405d); /* DRAM timings */
367 	reg_w(sd, 0x04, 0x0030); /* SDRAM timings */
368 
369 	reg_w(sd, 0x20, y0 & 0xffff); /* Y buf.0, low */
370 	reg_w(sd, 0x21, y0 >> 16);    /* Y buf.0, high */
371 	reg_w(sd, 0x24, u0 & 0xffff); /* U buf.0, low */
372 	reg_w(sd, 0x25, u0 >> 16);    /* U buf.0, high */
373 	reg_w(sd, 0x28, v0 & 0xffff); /* V buf.0, low */
374 	reg_w(sd, 0x29, v0 >> 16);    /* V buf.0, high */
375 
376 	reg_w(sd, 0x22, y1 & 0xffff); /* Y buf.1, low */
377 	reg_w(sd, 0x23, y1 >> 16);    /* Y buf.1, high */
378 	reg_w(sd, 0x26, u1 & 0xffff); /* U buf.1, low */
379 	reg_w(sd, 0x27, u1 >> 16);    /* U buf.1, high */
380 	reg_w(sd, 0x2a, v1 & 0xffff); /* V buf.1, low */
381 	reg_w(sd, 0x2b, v1 >> 16);    /* V buf.1, high */
382 
383 	reg_w(sd, 0x32, y1 & 0xffff); /* JPEG buf 0 low */
384 	reg_w(sd, 0x33, y1 >> 16);    /* JPEG buf 0 high */
385 
386 	reg_w(sd, 0x34, y1 & 0xffff); /* JPEG buf 1 low */
387 	reg_w(sd, 0x35, y1 >> 16);    /* JPEG bug 1 high */
388 
389 	reg_w(sd, 0x36, 0x0000);/* JPEG restart interval */
390 	reg_w(sd, 0x37, 0x0804);/*JPEG VLE FIFO threshold*/
391 	reg_w(sd, 0x38, 0x0000);/* disable hw up-scaling */
392 	reg_w(sd, 0x3f, 0x0000); /* JPEG/MCTL test data */
393 }
394 
395 static void w9968cf_set_crop_window(struct sd *sd)
396 {
397 	int start_cropx, start_cropy,  x, y, fw, fh, cw, ch,
398 	    max_width, max_height;
399 
400 	if (sd->sif) {
401 		max_width  = 352;
402 		max_height = 288;
403 	} else {
404 		max_width  = 640;
405 		max_height = 480;
406 	}
407 
408 	if (sd->sensor == SEN_OV7620) {
409 		/*
410 		 * Sigh, this is dependend on the clock / framerate changes
411 		 * made by the frequency control, sick.
412 		 *
413 		 * Note we cannot use v4l2_ctrl_g_ctrl here, as we get called
414 		 * from ov519.c:setfreq() with the ctrl lock held!
415 		 */
416 		if (sd->freq->val == 1) {
417 			start_cropx = 277;
418 			start_cropy = 37;
419 		} else {
420 			start_cropx = 105;
421 			start_cropy = 37;
422 		}
423 	} else {
424 		start_cropx = 320;
425 		start_cropy = 35;
426 	}
427 
428 	/* Work around to avoid FP arithmetic */
429 	#define SC(x) ((x) << 10)
430 
431 	/* Scaling factors */
432 	fw = SC(sd->gspca_dev.pixfmt.width) / max_width;
433 	fh = SC(sd->gspca_dev.pixfmt.height) / max_height;
434 
435 	cw = (fw >= fh) ? max_width : SC(sd->gspca_dev.pixfmt.width) / fh;
436 	ch = (fw >= fh) ? SC(sd->gspca_dev.pixfmt.height) / fw : max_height;
437 
438 	sd->sensor_width = max_width;
439 	sd->sensor_height = max_height;
440 
441 	x = (max_width - cw) / 2;
442 	y = (max_height - ch) / 2;
443 
444 	reg_w(sd, 0x10, start_cropx + x);
445 	reg_w(sd, 0x11, start_cropy + y);
446 	reg_w(sd, 0x12, start_cropx + x + cw);
447 	reg_w(sd, 0x13, start_cropy + y + ch);
448 }
449 
450 static void w9968cf_mode_init_regs(struct sd *sd)
451 {
452 	int val, vs_polarity, hs_polarity;
453 
454 	w9968cf_set_crop_window(sd);
455 
456 	reg_w(sd, 0x14, sd->gspca_dev.pixfmt.width);
457 	reg_w(sd, 0x15, sd->gspca_dev.pixfmt.height);
458 
459 	/* JPEG width & height */
460 	reg_w(sd, 0x30, sd->gspca_dev.pixfmt.width);
461 	reg_w(sd, 0x31, sd->gspca_dev.pixfmt.height);
462 
463 	/* Y & UV frame buffer strides (in WORD) */
464 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
465 	    V4L2_PIX_FMT_JPEG) {
466 		reg_w(sd, 0x2c, sd->gspca_dev.pixfmt.width / 2);
467 		reg_w(sd, 0x2d, sd->gspca_dev.pixfmt.width / 4);
468 	} else
469 		reg_w(sd, 0x2c, sd->gspca_dev.pixfmt.width);
470 
471 	reg_w(sd, 0x00, 0xbf17); /* reset everything */
472 	reg_w(sd, 0x00, 0xbf10); /* normal operation */
473 
474 	/* Transfer size in WORDS (for UYVY format only) */
475 	val = sd->gspca_dev.pixfmt.width * sd->gspca_dev.pixfmt.height;
476 	reg_w(sd, 0x3d, val & 0xffff); /* low bits */
477 	reg_w(sd, 0x3e, val >> 16);    /* high bits */
478 
479 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
480 	    V4L2_PIX_FMT_JPEG) {
481 		/* We may get called multiple times (usb isoc bw negotiat.) */
482 		jpeg_define(sd->jpeg_hdr, sd->gspca_dev.pixfmt.height,
483 			    sd->gspca_dev.pixfmt.width, 0x22); /* JPEG 420 */
484 		jpeg_set_qual(sd->jpeg_hdr, v4l2_ctrl_g_ctrl(sd->jpegqual));
485 		w9968cf_upload_quantizationtables(sd);
486 		v4l2_ctrl_grab(sd->jpegqual, true);
487 	}
488 
489 	/* Video Capture Control Register */
490 	if (sd->sensor == SEN_OV7620) {
491 		/* Seems to work around a bug in the image sensor */
492 		vs_polarity = 1;
493 		hs_polarity = 1;
494 	} else {
495 		vs_polarity = 1;
496 		hs_polarity = 0;
497 	}
498 
499 	val = (vs_polarity << 12) | (hs_polarity << 11);
500 
501 	/* NOTE: We may not have enough memory to do double buffering while
502 	   doing compression (amount of memory differs per model cam).
503 	   So we use the second image buffer also as jpeg stream buffer
504 	   (see w9968cf_init), and disable double buffering. */
505 	if (w9968cf_vga_mode[sd->gspca_dev.curr_mode].pixelformat ==
506 	    V4L2_PIX_FMT_JPEG) {
507 		/* val |= 0x0002; YUV422P */
508 		val |= 0x0003; /* YUV420P */
509 	} else
510 		val |= 0x0080; /* Enable HW double buffering */
511 
512 	/* val |= 0x0020; enable clamping */
513 	/* val |= 0x0008; enable (1-2-1) filter */
514 	/* val |= 0x000c; enable (2-3-6-3-2) filter */
515 
516 	val |= 0x8000; /* capt. enable */
517 
518 	reg_w(sd, 0x16, val);
519 
520 	sd->gspca_dev.empty_packet = 0;
521 }
522 
523 static void w9968cf_stop0(struct sd *sd)
524 {
525 	v4l2_ctrl_grab(sd->jpegqual, false);
526 	reg_w(sd, 0x39, 0x0000); /* disable JPEG encoder */
527 	reg_w(sd, 0x16, 0x0000); /* stop video capture */
528 }
529 
530 /* The w9968cf docs say that a 0 sized packet means EOF (and also SOF
531    for the next frame). This seems to simply not be true when operating
532    in JPEG mode, in this case there may be empty packets within the
533    frame. So in JPEG mode use the JPEG SOI marker to detect SOF.
534 
535    Note to make things even more interesting the w9968cf sends *PLANAR* jpeg,
536    to be precise it sends: SOI, SOF, DRI, SOS, Y-data, SOS, U-data, SOS,
537    V-data, EOI. */
538 static void w9968cf_pkt_scan(struct gspca_dev *gspca_dev,
539 			u8 *data,			/* isoc packet */
540 			int len)			/* iso packet length */
541 {
542 	struct sd *sd = (struct sd *) gspca_dev;
543 
544 	if (w9968cf_vga_mode[gspca_dev->curr_mode].pixelformat ==
545 	    V4L2_PIX_FMT_JPEG) {
546 		if (len >= 2 &&
547 		    data[0] == 0xff &&
548 		    data[1] == 0xd8) {
549 			gspca_frame_add(gspca_dev, LAST_PACKET,
550 					NULL, 0);
551 			gspca_frame_add(gspca_dev, FIRST_PACKET,
552 					sd->jpeg_hdr, JPEG_HDR_SZ);
553 			/* Strip the ff d8, our own header (which adds
554 			   huffman and quantization tables) already has this */
555 			len -= 2;
556 			data += 2;
557 		}
558 	} else {
559 		/* In UYVY mode an empty packet signals EOF */
560 		if (gspca_dev->empty_packet) {
561 			gspca_frame_add(gspca_dev, LAST_PACKET,
562 						NULL, 0);
563 			gspca_frame_add(gspca_dev, FIRST_PACKET,
564 					NULL, 0);
565 			gspca_dev->empty_packet = 0;
566 		}
567 	}
568 	gspca_frame_add(gspca_dev, INTER_PACKET, data, len);
569 }
570