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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* SN9C2028 common functions
*
* Copyright (C) 2009 Theodore Kilgore <kilgota@auburn,edu>
*
* Based closely upon the file gspca/pac_common.h
*/
static const unsigned char sn9c2028_sof_marker[] = {
0xff, 0xff, 0x00, 0xc4, 0xc4, 0x96,
0x00,
0x00, /* seq */
0x00,
0x00,
0x00, /* avg luminance lower 8 bit */
0x00, /* avg luminance higher 8 bit */
};
static unsigned char *sn9c2028_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] == sn9c2028_sof_marker[sd->sof_read]) ||
(sd->sof_read > 5)) {
sd->sof_read++;
if (sd->sof_read == 11)
sd->avg_lum_l = m[i];
if (sd->sof_read == 12)
sd->avg_lum = (m[i] << 8) + sd->avg_lum_l;
if (sd->sof_read == sizeof(sn9c2028_sof_marker)) {
gspca_dbg(gspca_dev, D_FRAM,
"SOF found, bytes to analyze: %u - Frame starts at byte #%u\n",
len, i + 1);
sd->sof_read = 0;
return m + i + 1;
}
} else {
sd->sof_read = 0;
}
}
return NULL;
}
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