1 files changed, 48 insertions, 0 deletions
diff --git a/drivers/media/usb/gspca/sn9c2028.h b/drivers/media/usb/gspca/sn9c2028.h
new file mode 100644
index 000000000..beb5d2a5d
--- /dev/null
+++ b/drivers/media/usb/gspca/sn9c2028.h
@@ -0,0 +1,48 @@
+/* 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;
+}