MIX_L_SRC_CON
mtk_ddp_write(cmdq_pkt, alpha_con, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_CON(idx));
MIX_L_SRC_CON(0));
MIX_L_SRC_CON(1));
MIX_L_SRC_CON(2));
MIX_L_SRC_CON(3));