[linux-2.6-block.git] / drivers / media / video / gspca / pac_common.h

/*
 * Pixart PAC207BCA / PAC73xx common functions
 *
 * Copyright (C) 2008 Hans de Goede <j.w.r.degoede@hhs.nl>
 * Copyright (C) 2005 Thomas Kaiser thomas@kaiser-linux.li
 * Copyleft (C) 2005 Michel Xhaard mxhaard@magic.fr
 *
 * V4L2 by Jean-Francois Moine <http://moinejf.free.fr>
 *
 * 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
 * (at your option) 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

/* We calculate the autogain at the end of the transfer of a frame, at this
   moment a frame with the old settings is being transmitted, and a frame is
   being captured with the old settings. So if we adjust the autogain we must
   ignore atleast the 2 next frames for the new settings to come into effect
   before doing any other adjustments */
#define PAC_AUTOGAIN_IGNORE_FRAMES	3

static const unsigned char pac_sof_marker[5] =
		{ 0xff, 0xff, 0x00, 0xff, 0x96 };

/*
   The following state machine finds the SOF marker sequence
   0xff, 0xff, 0x00, 0xff, 0x96 in a byte stream.

	   +----------+
	   | 0: START |<---------------\
	   +----------+<-\             |
	     |       \---/otherwise    |
	     v 0xff                    |
	   +----------+ otherwise      |
	   |     1    |--------------->*
	   |          |                ^
	   +----------+                |
	     |                         |
	     v 0xff                    |
	   +----------+<-\0xff         |
	/->|          |--/             |
	|  |     2    |--------------->*
	|  |          | otherwise      ^
	|  +----------+                |
	|    |                         |
	|    v 0x00                    |
	|  +----------+                |
	|  |     3    |                |
	|  |          |--------------->*
	|  +----------+ otherwise      ^
	|    |                         |
   0xff |    v 0xff                    |
	|  +----------+                |
	\--|     4    |                |
	   |          |----------------/
	   +----------+ otherwise
	     |
	     v 0x96
	   +----------+
	   |  FOUND   |
	   +----------+
*/

static unsigned char *pac_find_sof(u8 *sof_read,
					unsigned char *m, int len)
{
	int i;

	/* Search for the SOF marker (fixed part) in the header */
	for (i = 0; i < len; i++) {
		switch (*sof_read) {
		case 0:
			if (m[i] == 0xff)
				*sof_read = 1;
			break;
		case 1:
			if (m[i] == 0xff)
				*sof_read = 2;
			else
				*sof_read = 0;
			break;
		case 2:
			switch (m[i]) {
			case 0x00:
				*sof_read = 3;
				break;
			case 0xff:
				/* stay in this state */
				break;
			default:
				*sof_read = 0;
			}
			break;
		case 3:
			if (m[i] == 0xff)
				*sof_read = 4;
			else
				*sof_read = 0;
			break;
		case 4:
			switch (m[i]) {
			case 0x96:
				/* Pattern found */
				PDEBUG(D_FRAM,
					"SOF found, bytes to analyze: %u."
					" Frame starts at byte #%u",
					len, i + 1);
				*sof_read = 0;
				return m + i + 1;
				break;
			case 0xff:
				*sof_read = 2;
				break;
			default:
				*sof_read = 0;
			}
			break;
		default:
			*sof_read = 0;
		}
	}

	return NULL;
}
Commit	Line	Data
327c4abf HG	1	/*
	2	* Pixart PAC207BCA / PAC73xx common functions
	3	*
	4	* Copyright (C) 2008 Hans de Goede <j.w.r.degoede@hhs.nl>
	5	* Copyright (C) 2005 Thomas Kaiser thomas@kaiser-linux.li
	6	* Copyleft (C) 2005 Michel Xhaard mxhaard@magic.fr
	7	*
	8	* V4L2 by Jean-Francois Moine <http://moinejf.free.fr>
	9	*
	10	* This program is free software; you can redistribute it and/or modify
	11	* it under the terms of the GNU General Public License as published by
	12	* the Free Software Foundation; either version 2 of the License, or
	13	* (at your option) any later version.
	14	*
	15	* This program is distributed in the hope that it will be useful,
	16	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	17	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	18	* GNU General Public License for more details.
	19	*
	20	* You should have received a copy of the GNU General Public License
	21	* along with this program; if not, write to the Free Software
	22	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	23	*
	24	*/
	25
8a5b2e90 HG	26	/* We calculate the autogain at the end of the transfer of a frame, at this
	27	moment a frame with the old settings is being transmitted, and a frame is
	28	being captured with the old settings. So if we adjust the autogain we must
	29	ignore atleast the 2 next frames for the new settings to come into effect
	30	before doing any other adjustments */
	31	#define PAC_AUTOGAIN_IGNORE_FRAMES 3
	32
327c4abf HG	33	static const unsigned char pac_sof_marker[5] =
	34	{ 0xff, 0xff, 0x00, 0xff, 0x96 };
	35
e0d49e2d MN	36	/*
	37	The following state machine finds the SOF marker sequence
	38	0xff, 0xff, 0x00, 0xff, 0x96 in a byte stream.
	39
	40	+----------+
	41	\| 0: START \|<---------------\
	42	+----------+<-\ \|
	43	\| \---/otherwise \|
	44	v 0xff \|
	45	+----------+ otherwise \|
	46	\| 1 \|--------------->*
	47	\| \| ^
	48	+----------+ \|
	49	\| \|
	50	v 0xff \|
	51	+----------+<-\0xff \|
	52	/->\| \|--/ \|
	53	\| \| 2 \|--------------->*
	54	\| \| \| otherwise ^
	55	\| +----------+ \|
	56	\| \| \|
	57	\| v 0x00 \|
	58	\| +----------+ \|
	59	\| \| 3 \| \|
	60	\| \| \|--------------->*
	61	\| +----------+ otherwise ^
	62	\| \| \|
	63	0xff \| v 0xff \|
	64	\| +----------+ \|
	65	\--\| 4 \| \|
	66	\| \|----------------/
	67	+----------+ otherwise
	68	\|
	69	v 0x96
	70	+----------+
	71	\| FOUND \|
	72	+----------+
	73	*/
	74
a6b69e40	75	static unsigned char pac_find_sof(u8 sof_read,
327c4abf HG	76	unsigned char *m, int len)
327c4abf HG	77	{
327c4abf HG	78	int i;
	79
	80	/* Search for the SOF marker (fixed part) in the header */
	81	for (i = 0; i < len; i++) {
a6b69e40	82	switch (*sof_read) {
e0d49e2d MN	83	case 0:
e0d49e2d MN	84	if (m[i] == 0xff)
a6b69e40	85	*sof_read = 1;
e0d49e2d MN	86	break;
	87	case 1:
	88	if (m[i] == 0xff)
a6b69e40	89	*sof_read = 2;
e0d49e2d	90	else
a6b69e40	91	*sof_read = 0;
e0d49e2d MN	92	break;
	93	case 2:
	94	switch (m[i]) {
	95	case 0x00:
a6b69e40	96	*sof_read = 3;
e0d49e2d MN	97	break;
	98	case 0xff:
	99	/* stay in this state */
	100	break;
	101	default:
a6b69e40	102	*sof_read = 0;
e0d49e2d MN	103	}
	104	break;
	105	case 3:
	106	if (m[i] == 0xff)
a6b69e40	107	*sof_read = 4;
e0d49e2d	108	else
a6b69e40	109	*sof_read = 0;
e0d49e2d MN	110	break;
	111	case 4:
	112	switch (m[i]) {
	113	case 0x96:
	114	/* Pattern found */
8a5b2e90	115	PDEBUG(D_FRAM,
327c4abf HG	116	"SOF found, bytes to analyze: %u."
	117	" Frame starts at byte #%u",
	118	len, i + 1);
a6b69e40	119	*sof_read = 0;
327c4abf	120	return m + i + 1;
e0d49e2d MN	121	break;
e0d49e2d MN	122	case 0xff:
a6b69e40	123	*sof_read = 2;
e0d49e2d MN	124	break;
e0d49e2d MN	125	default:
a6b69e40	126	*sof_read = 0;
327c4abf	127	}
e0d49e2d MN	128	break;
e0d49e2d MN	129	default:
a6b69e40	130	*sof_read = 0;
327c4abf HG	131	}
	132	}
	133
	134	return NULL;
	135	}