sensor_write_mask
sensor_write_mask(gspca_dev, 0x00d, 0x0004, 0x000c);
sensor_write_mask(gspca_dev, 0x020, val ? 0x0002 : 0x0000 , 0x0002);
sensor_write_mask(gspca_dev, 0x020, val ? 0x0001 : 0x0000 , 0x0001);