[media] gspca - sonixj: Move the avg lum computation to a separate function

Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/gspca/sonixj.c

@@ -2757,6 +2757,29 @@ static void do_autogain(struct gspca_dev *gspca_dev)
 	}
 }
 
+/* set the average luminosity from an isoc marker */
+static void set_lum(struct sd *sd,
+		    u8 *data)
+{
+	int avg_lum;
+
+	/*	w0 w1 w2
+	 *	w3 w4 w5
+	 *	w6 w7 w8
+	 */
+	avg_lum = (data[27] << 8) + data[28]		/* w3 */
+
+		+ (data[31] << 8) + data[32]		/* w5 */
+
+		+ (data[23] << 8) + data[24]		/* w1 */
+
+		+ (data[35] << 8) + data[36]		/* w7 */
+
+		+ (data[29] << 10) + (data[30] << 2);	/* w4 * 4 */
+	avg_lum >>= 10;
+	atomic_set(&sd->avg_lum, avg_lum);
+}
+
 /* scan the URB packets */
 /* This function is run at interrupt level. */
 static void sd_pkt_scan(struct gspca_dev *gspca_dev,
@@ -2764,7 +2787,7 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
 			int len)			/* iso packet length */
 {
 	struct sd *sd = (struct sd *) gspca_dev;
-	int sof, avg_lum;
+	int sof;
 
 	/* the image ends on a 64 bytes block starting with
 	 *	ff d9 ff ff 00 c4 c4 96
@@ -2795,23 +2818,8 @@ static void sd_pkt_scan(struct gspca_dev *gspca_dev,
 	/* end of image found - remove the trailing data */
 	gspca_dev->image_len = sof + 2;
 	gspca_frame_add(gspca_dev, LAST_PACKET, NULL, 0);
-	if (sd->ag_cnt < 0)
-		return;
-/* w1 w2 w3 */
-/* w4 w5 w6 */
-/* w7 w8 */
-/* w4 */
-	avg_lum = ((data[sof + 29] << 8) | data[sof + 30]) >> 6;
-/* w6 */
-	avg_lum += ((data[sof + 33] << 8) | data[sof + 34]) >> 6;
-/* w2 */
-	avg_lum += ((data[sof + 25] << 8) | data[sof + 26]) >> 6;
-/* w8 */
-	avg_lum += ((data[sof + 37] << 8) | data[sof + 38]) >> 6;
-/* w5 */
-	avg_lum += ((data[sof + 31] << 8) | data[sof + 32]) >> 4;
-	avg_lum >>= 4;
-	atomic_set(&sd->avg_lum, avg_lum);
+	if (sd->ag_cnt >= 0)
+		set_lum(sd, data + sof + 2);
 }
 
 static int sd_set_jcomp(struct gspca_dev *gspca_dev,