U3D_LTSSM_INTR
mtu3_writel(mbase, U3D_LTSSM_INTR, ~0x0);
ltssm = mtu3_readl(mbase, U3D_LTSSM_INTR);
mtu3_writel(mbase, U3D_LTSSM_INTR, ltssm); /* W1C */