CH7006_BLACK_LEVEL
ch7006_load_reg(client, state, CH7006_BLACK_LEVEL);
regs[CH7006_BLACK_LEVEL] = bitf(CH7006_BLACK_LEVEL_0, black_level);
ch7006_load_reg(client, state, CH7006_BLACK_LEVEL);
ch7006_save_reg(client, state, CH7006_BLACK_LEVEL);