[media] tvp514x: fix querystd

Return V4L2_STD_UNKNOWN if no signal is detected.
Otherwise AND the standard mask with the detected standards.

Signed-off-by: Hans Verkuil <[e-mail]>
Acked-by: Lad, Prabhakar <[e-mail]>
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>

drivers/media/i2c/tvp514x.c

···
 	if (std_id == NULL)
 		return -EINVAL;
 
-	*std_id = V4L2_STD_UNKNOWN;
-
 	/* To query the standard the TVP514x must power on the ADCs. */
 	if (!decoder->streaming) {
 		tvp514x_s_stream(sd, 1);
···
 
 	/* query the current standard */
 	current_std = tvp514x_query_current_std(sd);
-	if (current_std == STD_INVALID)
+	if (current_std == STD_INVALID) {
+		*std_id = V4L2_STD_UNKNOWN;
 		return 0;
+	}
 
 	input_sel = decoder->input;
 
···
 	}
 	/* check whether signal is locked */
 	sync_lock_status = tvp514x_read_reg(sd, REG_STATUS1);
-	if (lock_mask != (sync_lock_status & lock_mask))
+	if (lock_mask != (sync_lock_status & lock_mask)) {
+		*std_id = V4L2_STD_UNKNOWN;
 		return 0;	/* No input detected */
+	}
 
-	*std_id = decoder->std_list[current_std].standard.id;
+	*std_id &= decoder->std_list[current_std].standard.id;
 
 	v4l2_dbg(1, debug, sd, "Current STD: %s\n",
 			decoder->std_list[current_std].standard.name);