PLLC_READ
uint32_t pllctl_reg = PLLC_READ(sc, AM18XX_PLLC_PLLCTL);
uint32_t prediv_reg = PLLC_READ(sc, AM18XX_PLLC_PREDIV);
uint32_t pllm_reg = PLLC_READ(sc, AM18XX_PLLC_PLLM);
uint32_t postdiv_reg = PLLC_READ(sc, AM18XX_PLLC_POSTDIV);
uint32_t plldiv_reg = PLLC_READ(sc, plldiv_regaddr);