HPET_Tn_CMP
l = hpet_readl(HPET_Tn_CMP(i));
h = hpet_readl(HPET_Tn_CMP(i)+4);
hpet_writel(cmp, HPET_Tn_CMP(channel));
hpet_writel((unsigned int)delta, HPET_Tn_CMP(channel));
hpet_writel(cnt, HPET_Tn_CMP(channel));