drivers: clock: stm32c0: Add an option to enable CRS for HSI48

Allows enabling the Clock Recovery System (CRS) for HSI48 to achieve
the expected accuracy for USB transfers. Uses USB SOF packet by default.

Signed-off-by: Tomáš Juřena <[email protected]>

Author: jurenat

drivers/clock_control/clock_stm32c0.c

@@ -8,6 +8,7 @@
 
 #include <soc.h>
 #include <stm32_ll_bus.h>
+#include <stm32_ll_crs.h>
 #include <stm32_ll_rcc.h>
 #include <stm32_ll_utils.h>
 #include <zephyr/drivers/clock_control.h>
@@ -22,4 +23,11 @@ void config_enable_default_clocks(void)
 {
 	/* Enable the power interface clock */
 	LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_PWR);
+
+#if IS_ENABLED(STM32_HSI48_CRS_USB_SOF)
+	LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_CRS);
+	LL_CRS_SetSyncSignalSource(LL_CRS_SYNC_SOURCE_USB);
+	LL_CRS_EnableAutoTrimming();
+	LL_CRS_EnableFreqErrorCounter();
+#endif
 }