stm32/h7: Implemented support for the HSI48

include/libopencm3/stm32/h7/rcc.h

@@ -770,6 +770,13 @@ BEGIN_DECLS
  */
 void rcc_clock_setup_pll(const struct rcc_pll_config *config);
 
+/**
+ * Setup and bring up the HSI48 for use by the USB controller.
+ *
+ * Note: Should be used with the CRS for stability
+ */
+void rcc_clock_setup_hsi48(void);
+
 /**
  * Get the clock rate (in Hz) of the specified clock source. There are
  * numerous clock sources and configurations on the H7, so rates for each