+#define AT91_PMC_PCR_GCKCSS (0x7 << 8)
+#define AT91_PMC_PCR_GCKCSS_MASK 0x07
+#define AT91_PMC_PCR_GCKCSS_OFFSET 8
+#define AT91_PMC_PCR_GCKCSS_(x) ((x & 0x07) << 8)
+#define AT91_PMC_PCR_GCKCSS_SLOW_CLK (0x0 << 8)
+#define AT91_PMC_PCR_GCKCSS_MAIN_CLK (0x1 << 8)
+#define AT91_PMC_PCR_GCKCSS_PLLA_CLK (0x2 << 8)
+#define AT91_PMC_PCR_GCKCSS_UPLL_CLK (0x3 << 8)
+#define AT91_PMC_PCR_GCKCSS_MCK_CLK (0x4 << 8)
+#define AT91_PMC_PCR_GCKCSS_AUDIO_CLK (0x5 << 8)