DP_CTL_REF_CLK_SEL
switch (dp_ctrl & DP_CTL_REF_CLK_SEL) {
#define DP_CTL_REF_CLK_SEL_COSC __SHIFTIN(0x2, DP_CTL_REF_CLK_SEL)
#define DP_CTL_REF_CLK_SEL_FPM __SHIFTIN(0x3, DP_CTL_REF_CLK_SEL)