SYS1_INFRAC
status = sysctl_r32(SYSCTL_SYS1, SYS1_INFRAC);
freq << (GPPC_OFFSET + 2) , SYS1_INFRAC);
sysctl_w32_mask(SYSCTL_SYS1, 0, 1 << (GPPC_OFFSET + 1), SYS1_INFRAC);