+#define SSIFSR_TDC_MASK 0x3f
+#define SSIFSR_TDC_SHIFT 24
+#define SSIFSR_RDC_MASK 0x3f
+#define SSIFSR_RDC_SHIFT 8
+
+#define SSIFSR_TDC(x) (((x) & 0x1f) << 24)

This is not used.
If you use it, you can use SSIFSR_TDC_SHIFT and SSIFSR_TDC_MASK.

+#define SSIFSR_TDE BIT(16)
+#define SSIFSR_RDC(x) (((x) & 0x1f) << 8)

Same above.