aboutsummaryrefslogtreecommitdiff
path: root/drivers/media/video/gspca
diff options
context:
space:
mode:
authorHans de Goede <j.w.r.degoede@hhs.nl>2008-09-03 17:12:14 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2008-09-03 18:37:24 -0300
commit327c4abf74a4426676df6c359b2a3dea2a5d126e (patch)
tree005359b56ee32e6dc645b57d0f0da518292719a8 /drivers/media/video/gspca
parent62ee8eeebd1bf6c29977800ac18dfcecf584d42e (diff)
V4L/DVB (8812): gspca: Do pac73xx webcams work.
- documentation for some registers - some preparations for adding autogain_n_exposure functionality - various pac7311 fixes - disable brightness and colors controls for 7311 - fix contrast control for 7311 - add hflip and vflip controls for 7311 - minimal jpeg header - proper SOF detection Signed-off-by: Hans de Goede <j.w.r.degoede@hhs.nl> Signed-off-by: Jean-Francois Moine <moinejf@free.fr> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/gspca')
-rw-r--r--drivers/media/video/gspca/pac207.c36
-rw-r--r--drivers/media/video/gspca/pac7311.c309
-rw-r--r--drivers/media/video/gspca/pac_common.h53
3 files changed, 220 insertions, 178 deletions
diff --git a/drivers/media/video/gspca/pac207.c b/drivers/media/video/gspca/pac207.c
index d9668f4cb4d..620c9631629 100644
--- a/drivers/media/video/gspca/pac207.c
+++ b/drivers/media/video/gspca/pac207.c
@@ -181,9 +181,6 @@ static const __u8 pac207_sensor_init[][8] = {
/* 48 reg_72 Rate Control end BalSize_4a =0x36 */
static const __u8 PacReg72[] = { 0x00, 0x00, 0x36, 0x00 };
-static const unsigned char pac207_sof_marker[5] =
- { 0xff, 0xff, 0x00, 0xff, 0x96 };
-
static int pac207_write_regs(struct gspca_dev *gspca_dev, u16 index,
const u8 *buffer, u16 length)
{
@@ -367,31 +364,8 @@ static void pac207_do_auto_gain(struct gspca_dev *gspca_dev)
sd->autogain_ignore_frames = PAC207_AUTOGAIN_IGNORE_FRAMES;
}
-static unsigned char *pac207_find_sof(struct gspca_dev *gspca_dev,
- unsigned char *m, int len)
-{
- struct sd *sd = (struct sd *) gspca_dev;
- int i;
-
- /* Search for the SOF marker (fixed part) in the header */
- for (i = 0; i < len; i++) {
- if (m[i] == pac207_sof_marker[sd->sof_read]) {
- sd->sof_read++;
- if (sd->sof_read == sizeof(pac207_sof_marker)) {
- PDEBUG(D_STREAM,
- "SOF found, bytes to analyze: %u."
- " Frame starts at byte #%u",
- len, i + 1);
- sd->sof_read = 0;
- return m + i + 1;
- }
- } else {
- sd->sof_read = 0;
- }
- }
-
- return NULL;
-}
+/* Include pac common sof detection functions */
+#include "pac_common.h"
static void sd_pkt_scan(struct gspca_dev *gspca_dev,
struct gspca_frame *frame,
@@ -401,14 +375,14 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
struct sd *sd = (struct sd *) gspca_dev;
unsigned char *sof;
- sof = pac207_find_sof(gspca_dev, data, len);
+ sof = pac_find_sof(gspca_dev, data, len);
if (sof) {
int n;
/* finish decoding current frame */
n = sof - data;
- if (n > sizeof pac207_sof_marker)
- n -= sizeof pac207_sof_marker;
+ if (n > sizeof pac_sof_marker)
+ n -= sizeof pac_sof_marker;
else
n = 0;
frame = gspca_frame_add(gspca_dev, LAST_PACKET, frame,
diff --git a/drivers/media/video/gspca/pac7311.c b/drivers/media/video/gspca/pac7311.c
index 4cc9379ee41..bed04cc9a58 100644
--- a/drivers/media/video/gspca/pac7311.c
+++ b/drivers/media/video/gspca/pac7311.c
@@ -19,10 +19,36 @@
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
+/* Some documentation about various registers as determined by trial and error.
+ When the register addresses differ between the 7202 and the 7311 the 2
+ different addresses are written as 7302addr/7311addr, when one of the 2
+ addresses is a - sign that register description is not valid for the
+ matching IC.
+
+ Register page 1:
+
+ Address Description
+ -/0x08 Unknown compressor related, must always be 8 except when not
+ in 640x480 resolution and page 4 reg 2 <= 3 then set it to 9 !
+ -/0x1b Auto white balance related, bit 0 is AWB enable (inverted)
+ bits 345 seem to toggle per color gains on/off (inverted)
+ 0x78 Global control, bit 6 controls the LED (inverted)
+ -/0x80 JPEG compression ratio ? Best not touched
+
+ Register page 3/4:
+
+ Address Description
+ 0x02 Clock divider 2-63, fps =~ 60 / val. Must be a multiple of 3 on
+ the 7302, so one of 3, 6, 9, ...
+ -/0x0f Master gain 1-245, low value = high gain
+ 0x10/- Master gain 0-31
+ -/0x10 Another gain 0-15, limited influence (1-2x gain I guess)
+ 0x21 Bitfield: 0-1 unused, 2-3 vflip/hflip, 4-5 unknown, 6-7 unused
+*/
+
#define MODULE_NAME "pac7311"
#include "gspca.h"
-#include "jpeg.h"
MODULE_AUTHOR("Thomas Kaiser thomas@kaiser-linux.li");
MODULE_DESCRIPTION("Pixart PAC7311");
@@ -32,25 +58,22 @@ MODULE_LICENSE("GPL");
struct sd {
struct gspca_dev gspca_dev; /* !! must be the first item */
- int lum_sum;
- atomic_t avg_lum;
- atomic_t do_gain;
-
unsigned char brightness;
unsigned char contrast;
unsigned char colors;
unsigned char autogain;
__u8 hflip;
__u8 vflip;
- __u8 qindex;
-
- char tosof; /* number of bytes before next start of frame */
- signed char ag_cnt;
-#define AG_CNT_START 13
__u8 sensor;
#define SENSOR_PAC7302 0
#define SENSOR_PAC7311 1
+
+ u8 sof_read;
+ u8 header_read;
+ u8 autogain_ignore_frames;
+
+ atomic_t avg_lum;
};
/* V4L2 controls supported by the driver */
@@ -92,7 +115,7 @@ static struct ctrl sd_ctrls[] = {
#define CONTRAST_MAX 255
.maximum = CONTRAST_MAX,
.step = 1,
-#define CONTRAST_DEF 60
+#define CONTRAST_DEF 127
.default_value = CONTRAST_DEF,
},
.set = sd_setcontrast,
@@ -243,7 +266,7 @@ static const __u8 start_7302[] = {
0x2a, 5, 0xc8, 0x00, 0x18, 0x12, 0x22,
0x64, 8, 0x00, 0x00, 0xf0, 0x01, 0x14, 0x44, 0x44, 0x44,
0x6e, 1, 0x08,
- 0xff, 1, 0x03, /* page 1 */
+ 0xff, 1, 0x01, /* page 1 */
0x78, 1, 0x00,
0, 0 /* end of sequence */
};
@@ -274,9 +297,9 @@ static const __u8 page3_7302[] = {
/* pac 7311 */
static const __u8 probe_7311[] = {
- 0x78, 0x40, /* Bit_0=start stream, Bit_7=LED */
- 0x78, 0x40, /* Bit_0=start stream, Bit_7=LED */
- 0x78, 0x44, /* Bit_0=start stream, Bit_7=LED */
+ 0x78, 0x40, /* Bit_0=start stream, Bit_6=LED */
+ 0x78, 0x40, /* Bit_0=start stream, Bit_6=LED */
+ 0x78, 0x44, /* Bit_0=start stream, Bit_6=LED */
0xff, 0x04,
0x27, 0x80,
0x28, 0xca,
@@ -340,18 +363,6 @@ static void reg_w_buf(struct gspca_dev *gspca_dev,
500);
}
-static __u8 reg_r(struct gspca_dev *gspca_dev,
- __u8 index)
-{
- usb_control_msg(gspca_dev->dev,
- usb_rcvctrlpipe(gspca_dev->dev, 0),
- 0, /* request */
- USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
- 0, /* value */
- index, gspca_dev->usb_buf, 1,
- 500);
- return gspca_dev->usb_buf[0];
-}
static void reg_w(struct gspca_dev *gspca_dev,
__u8 index,
@@ -413,7 +424,7 @@ static void reg_w_var(struct gspca_dev *gspca_dev,
reg_w_page(gspca_dev, page3_7302, sizeof page3_7302);
break;
default:
- if (len > 32) {
+ if (len > 64) {
PDEBUG(D_ERR|D_STREAM,
"Incorrect variable sequence");
return;
@@ -453,7 +464,7 @@ static int sd_config(struct gspca_dev *gspca_dev,
cam->nmodes = 1;
} else {
PDEBUG(D_CONF, "Find Sensor PAC7311");
- reg_w_seq(gspca_dev, probe_7302, sizeof probe_7302);
+ reg_w_seq(gspca_dev, probe_7311, sizeof probe_7311);
cam->cam_mode = vga_mode;
cam->nmodes = ARRAY_SIZE(vga_mode);
@@ -465,8 +476,6 @@ static int sd_config(struct gspca_dev *gspca_dev,
sd->autogain = AUTOGAIN_DEF;
sd->hflip = HFLIP_DEF;
sd->vflip = VFLIP_DEF;
- sd->qindex = 3;
- sd->ag_cnt = -1;
return 0;
}
@@ -497,6 +506,7 @@ static void setbrightcont(struct gspca_dev *gspca_dev)
reg_w(gspca_dev, 0xdc, 0x01);
}
+/* This function is used by pac7302 only */
static void setbrightness(struct gspca_dev *gspca_dev)
{
struct sd *sd = (struct sd *) gspca_dev;
@@ -506,7 +516,10 @@ static void setbrightness(struct gspca_dev *gspca_dev)
setbrightcont(gspca_dev);
return;
}
-/*jfm: inverted?*/
+/* HDG: this is not brightness but gain, I'll add gain and exposure controls
+ in a next patch */
+ return;
+
brightness = BRIGHTNESS_MAX - sd->brightness;
reg_w(gspca_dev, 0xff, 0x04);
reg_w(gspca_dev, 0x0e, 0x00);
@@ -524,12 +537,13 @@ static void setcontrast(struct gspca_dev *gspca_dev)
setbrightcont(gspca_dev);
return;
}
- reg_w(gspca_dev, 0xff, 0x01);
- reg_w(gspca_dev, 0x10, sd->contrast);
+ reg_w(gspca_dev, 0xff, 0x04);
+ reg_w(gspca_dev, 0x10, sd->contrast >> 4);
/* load registers to sensor (Bit 0, auto clear) */
reg_w(gspca_dev, 0x11, 0x01);
}
+/* This function is used by pac7302 only */
static void setcolors(struct gspca_dev *gspca_dev)
{
struct sd *sd = (struct sd *) gspca_dev;
@@ -551,36 +565,24 @@ static void setcolors(struct gspca_dev *gspca_dev)
reg_w(gspca_dev, 0x0f + 2 * i + 1, v);
}
reg_w(gspca_dev, 0xdc, 0x01);
- return;
+ PDEBUG(D_CONF|D_STREAM, "color: %i", sd->colors);
}
- reg_w(gspca_dev, 0xff, 0x01);
- reg_w(gspca_dev, 0x80, sd->colors);
- /* load registers to sensor (Bit 0, auto clear) */
- reg_w(gspca_dev, 0x11, 0x01);
- PDEBUG(D_CONF|D_STREAM, "color: %i", sd->colors);
}
-static void setautogain(struct gspca_dev *gspca_dev)
-{
- struct sd *sd = (struct sd *) gspca_dev;
-
- if (sd->autogain) {
- sd->lum_sum = 0;
- sd->ag_cnt = AG_CNT_START;
- } else {
- sd->ag_cnt = -1;
- }
-}
-
-/* this function is used by pac7302 only */
static void sethvflip(struct gspca_dev *gspca_dev)
{
struct sd *sd = (struct sd *) gspca_dev;
__u8 data;
- reg_w(gspca_dev, 0xff, 0x03); /* page 3 */
- data = (sd->hflip ? 0x00 : 0x08)
- | (sd->vflip ? 0x04 : 0x00);
+ if (sd->sensor == SENSOR_PAC7302) {
+ reg_w(gspca_dev, 0xff, 0x03); /* page 3 */
+ data = (sd->hflip ? 0x00 : 0x08)
+ | (sd->vflip ? 0x04 : 0x00);
+ } else {
+ reg_w(gspca_dev, 0xff, 0x04); /* page 3 */
+ data = (sd->hflip ? 0x04 : 0x00)
+ | (sd->vflip ? 0x08 : 0x00);
+ }
reg_w(gspca_dev, 0x21, data);
reg_w(gspca_dev, 0x11, 0x01);
}
@@ -588,7 +590,6 @@ static void sethvflip(struct gspca_dev *gspca_dev)
/* this function is called at open time */
static int sd_open(struct gspca_dev *gspca_dev)
{
- reg_w(gspca_dev, 0x78, 0x44); /* Turn on LED */
return 0;
}
@@ -596,7 +597,7 @@ static void sd_start(struct gspca_dev *gspca_dev)
{
struct sd *sd = (struct sd *) gspca_dev;
- sd->tosof = 0;
+ sd->sof_read = 0;
if (sd->sensor == SENSOR_PAC7302)
reg_w_var(gspca_dev, start_7302);
@@ -606,7 +607,6 @@ static void sd_start(struct gspca_dev *gspca_dev)
setcontrast(gspca_dev);
setbrightness(gspca_dev);
setcolors(gspca_dev);
- setautogain(gspca_dev);
/* set correct resolution */
switch (gspca_dev->cam.cam_mode[(int) gspca_dev->curr_mode].priv) {
@@ -621,7 +621,7 @@ static void sd_start(struct gspca_dev *gspca_dev)
break;
case 1: /* 320x240 pac7311 */
reg_w(gspca_dev, 0xff, 0x04);
- reg_w(gspca_dev, 0x02, 0x07);
+ reg_w(gspca_dev, 0x02, 0x03);
reg_w(gspca_dev, 0xff, 0x01);
reg_w(gspca_dev, 0x08, 0x09);
reg_w(gspca_dev, 0x17, 0x30);
@@ -650,6 +650,10 @@ static void sd_start(struct gspca_dev *gspca_dev)
reg_w(gspca_dev, 0x78, 0x44);
reg_w(gspca_dev, 0x78, 0x45);
}
+
+ sd->sof_read = 0;
+ sd->autogain_ignore_frames = 0;
+ atomic_set(&sd->avg_lum, -1);
}
static void sd_stopN(struct gspca_dev *gspca_dev)
@@ -657,6 +661,7 @@ static void sd_stopN(struct gspca_dev *gspca_dev)
struct sd *sd = (struct sd *) gspca_dev;
if (sd->sensor == SENSOR_PAC7302) {
+ reg_w(gspca_dev, 0xff, 0x01);
reg_w(gspca_dev, 0x78, 0x00);
reg_w(gspca_dev, 0x78, 0x00);
return;
@@ -668,9 +673,9 @@ static void sd_stopN(struct gspca_dev *gspca_dev)
reg_w(gspca_dev, 0x2a, 0x0e);
reg_w(gspca_dev, 0xff, 0x01);
reg_w(gspca_dev, 0x3e, 0x20);
- reg_w(gspca_dev, 0x78, 0x44); /* Bit_0=start stream, Bit_7=LED */
- reg_w(gspca_dev, 0x78, 0x44); /* Bit_0=start stream, Bit_7=LED */
- reg_w(gspca_dev, 0x78, 0x44); /* Bit_0=start stream, Bit_7=LED */
+ reg_w(gspca_dev, 0x78, 0x44); /* Bit_0=start stream, Bit_6=LED */
+ reg_w(gspca_dev, 0x78, 0x44); /* Bit_0=start stream, Bit_6=LED */
+ reg_w(gspca_dev, 0x78, 0x44); /* Bit_0=start stream, Bit_6=LED */
}
static void sd_stop0(struct gspca_dev *gspca_dev)
@@ -690,42 +695,22 @@ static void sd_close(struct gspca_dev *gspca_dev)
static void do_autogain(struct gspca_dev *gspca_dev)
{
- struct sd *sd = (struct sd *) gspca_dev;
- int luma;
- int luma_mean = 128;
- int luma_delta = 20;
- __u8 spring = 5;
- int Gbright;
-
- if (!atomic_read(&sd->do_gain))
- return;
- atomic_set(&sd->do_gain, 0);
-
- luma = atomic_read(&sd->avg_lum);
- Gbright = reg_r(gspca_dev, 0x02);
- PDEBUG(D_FRAM, "luma mean %d", luma);
- if (luma < luma_mean - luma_delta ||
- luma > luma_mean + luma_delta) {
- Gbright += (luma_mean - luma) >> spring;
- if (Gbright > 0x1a)
- Gbright = 0x1a;
- else if (Gbright < 4)
- Gbright = 4;
- PDEBUG(D_FRAM, "gbright %d", Gbright);
- if (sd->sensor == SENSOR_PAC7302) {
- reg_w(gspca_dev, 0xff, 0x03);
- reg_w(gspca_dev, 0x10, Gbright);
- /* load registers to sensor (Bit 0, auto clear) */
- reg_w(gspca_dev, 0x11, 0x01);
- } else {
- reg_w(gspca_dev, 0xff, 0x04);
- reg_w(gspca_dev, 0x0f, Gbright);
- /* load registers to sensor (Bit 0, auto clear) */
- reg_w(gspca_dev, 0x11, 0x01);
- }
- }
}
+static const unsigned char pac7311_jpeg_header1[] = {
+ 0xff, 0xd8, 0xff, 0xc0, 0x00, 0x11, 0x08
+};
+
+static const unsigned char pac7311_jpeg_header2[] = {
+ 0x03, 0x01, 0x21, 0x00, 0x02, 0x11, 0x01, 0x03, 0x11, 0x01, 0xff, 0xda,
+ 0x00, 0x0c, 0x03, 0x01, 0x00, 0x02, 0x11, 0x03, 0x11, 0x00, 0x3f, 0x00
+};
+
+/* Include pac common sof detection functions */
+#include "pac_common.h"
+
+#define HEADER_LENGTH 2
+
/* this function is run at interrupt level */
static void sd_pkt_scan(struct gspca_dev *gspca_dev,
struct gspca_frame *frame, /* target */
@@ -733,58 +718,89 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
int len) /* iso packet length */
{
struct sd *sd = (struct sd *) gspca_dev;
- int i;
-
-#define INTER_FRAME 0x53 /* eof + inter frame + sof */
-#define LUM_OFFSET 0x1e /* reverse offset / start of frame */
-
- /*
- * inside a frame, there may be:
- * escaped ff ('ff 00')
- * sequences'ff ff ff xx' to remove
- * end of frame ('ff d9')
- * at the end of frame, there are:
- * ff d9 end of frame
- * 0x33 bytes
- * one byte luminosity
- * 0x16 bytes
- * ff ff 00 ff 96 62 44 start of frame
- */
-
- if (sd->tosof != 0) { /* if outside a frame */
-
- /* get the luminosity and go to the start of frame */
- data += sd->tosof;
- len -= sd->tosof;
- if (sd->tosof > LUM_OFFSET)
- sd->lum_sum += data[-LUM_OFFSET];
- sd->tosof = 0;
- jpeg_put_header(gspca_dev, frame, sd->qindex, 0x21);
+ unsigned char *sof;
+
+ sof = pac_find_sof(gspca_dev, data, len);
+ if (sof) {
+ unsigned char tmpbuf[4];
+ int n, lum_offset, footer_length;
+
+ if (sd->sensor == SENSOR_PAC7302) {
+ lum_offset = 34 + sizeof pac_sof_marker;
+ footer_length = 74;
+ } else {
+ lum_offset = 24 + sizeof pac_sof_marker;
+ footer_length = 26;
+ }
+
+ /* Finish decoding current frame */
+ n = (sof - data) - (footer_length + sizeof pac_sof_marker);
+ if (n < 0) {
+ frame->data_end += n;
+ n = 0;
+ }
+ frame = gspca_frame_add(gspca_dev, INTER_PACKET, frame,
+ data, n);
+ if (gspca_dev->last_packet_type != DISCARD_PACKET &&
+ frame->data_end[-2] == 0xff &&
+ frame->data_end[-1] == 0xd9)
+ frame = gspca_frame_add(gspca_dev, LAST_PACKET, frame,
+ NULL, 0);
+
+ n = sof - data;
+ len -= n;
+ data = sof;
+
+ /* Get average lumination */
+ if (gspca_dev->last_packet_type == LAST_PACKET &&
+ n >= lum_offset) {
+ if (sd->sensor == SENSOR_PAC7302)
+ atomic_set(&sd->avg_lum,
+ (data[-lum_offset] << 8) |
+ data[-lum_offset + 1]);
+ else
+ atomic_set(&sd->avg_lum,
+ data[-lum_offset] +
+ data[-lum_offset + 1]);
+ } else {
+ atomic_set(&sd->avg_lum, -1);
+ }
+
+ /* Start the new frame with the jpeg header */
+ gspca_frame_add(gspca_dev, FIRST_PACKET, frame,
+ pac7311_jpeg_header1, sizeof(pac7311_jpeg_header1));
+ if (sd->sensor == SENSOR_PAC7302) {
+ /* The PAC7302 has the image rotated 90 degrees */
+ tmpbuf[0] = gspca_dev->width >> 8;
+ tmpbuf[1] = gspca_dev->width & 0xff;
+ tmpbuf[2] = gspca_dev->height >> 8;
+ tmpbuf[3] = gspca_dev->height & 0xff;
+ } else {
+ tmpbuf[0] = gspca_dev->height >> 8;
+ tmpbuf[1] = gspca_dev->height & 0xff;
+ tmpbuf[2] = gspca_dev->width >> 8;
+ tmpbuf[3] = gspca_dev->width & 0xff;
+ }
+ gspca_frame_add(gspca_dev, INTER_PACKET, frame, tmpbuf, 4);
+ gspca_frame_add(gspca_dev, INTER_PACKET, frame,
+ pac7311_jpeg_header2, sizeof(pac7311_jpeg_header2));
+
+ sd->header_read = 0;
}
- for (i = 0; i < len; i++) {
- if (data[i] != 0xff)
- continue;
- switch (data[i + 1]) {
- case 0xd9: /* 'ff d9' end of frame */
- frame = gspca_frame_add(gspca_dev,
- LAST_PACKET,
- frame, data, i + 2);
- data += i + INTER_FRAME;
- len -= i + INTER_FRAME;
- i = 0;
- if (len > -LUM_OFFSET)
- sd->lum_sum += data[-LUM_OFFSET];
- if (len < 0) {
- sd->tosof = -len;
- break;
- }
- jpeg_put_header(gspca_dev, frame, sd->qindex, 0x21);
- break;
+ if (sd->header_read < HEADER_LENGTH) {
+ /* skip the variable part of the sof header */
+ int needed = HEADER_LENGTH - sd->header_read;
+ if (len <= needed) {
+ sd->header_read += len;
+ return;
}
+ data += needed;
+ len -= needed;
+ sd->header_read = HEADER_LENGTH;
}
- gspca_frame_add(gspca_dev, INTER_PACKET,
- frame, data, i);
+
+ gspca_frame_add(gspca_dev, INTER_PACKET, frame, data, len);
}
static int sd_setbrightness(struct gspca_dev *gspca_dev, __s32 val)
@@ -846,8 +862,7 @@ static int sd_setautogain(struct gspca_dev *gspca_dev, __s32 val)
struct sd *sd = (struct sd *) gspca_dev;
sd->autogain = val;
- if (gspca_dev->streaming)
- setautogain(gspca_dev);
+
return 0;
}
diff --git a/drivers/media/video/gspca/pac_common.h b/drivers/media/video/gspca/pac_common.h
new file mode 100644
index 00000000000..a19b5d44c00
--- /dev/null
+++ b/drivers/media/video/gspca/pac_common.h
@@ -0,0 +1,53 @@
+/*
+ * 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
+ *
+ */
+
+static const unsigned char pac_sof_marker[5] =
+ { 0xff, 0xff, 0x00, 0xff, 0x96 };
+
+static unsigned char *pac_find_sof(struct gspca_dev *gspca_dev,
+ unsigned char *m, int len)
+{
+ struct sd *sd = (struct sd *) gspca_dev;
+ int i;
+
+ /* Search for the SOF marker (fixed part) in the header */
+ for (i = 0; i < len; i++) {
+ if (m[i] == pac_sof_marker[sd->sof_read]) {
+ sd->sof_read++;
+ if (sd->sof_read == sizeof(pac_sof_marker)) {
+ PDEBUG(D_STREAM,
+ "SOF found, bytes to analyze: %u."
+ " Frame starts at byte #%u",
+ len, i + 1);
+ sd->sof_read = 0;
+ return m + i + 1;
+ }
+ } else {
+ sd->sof_read = 0;
+ }
+ }
+
+ return NULL;
+}