Implement backup domain's data registers access

drv/bkp.c

@@ -109,6 +109,15 @@ void bkp_reset(void)
 	rcc_regs->BDCR.BDRST = 0;
 }
 
+void bkp_write_data(enum BkpData data_index, uint16_t data)
+{
+	bkp_regs->DR[data_index].D = data;
+}
+
+uint16_t bkp_read_data(enum BkpData data_index)
+{
+	return bkp_regs->DR[data_index].D;
+}
 
 //--local functions-------------------------------------------------------------
 

drv/bkp.h

@@ -39,6 +39,19 @@ enum BkpRtcIrq {
 	BKP_RTC_IRQ_OVERFLOW = 0x1 << 2,
 };
 
+enum BkpData {
+	BKP_DATA_LSI_CALIB,
+	BKP_DATA_1,
+	BKP_DATA_2,
+	BKP_DATA_3,
+	BKP_DATA_4,
+	BKP_DATA_5,
+	BKP_DATA_6,
+	BKP_DATA_7,
+	BKP_DATA_8,
+	BKP_DATA_9,
+};
+
 /**
  * Prototype of the IRQ callbacks that the applicative code can provide
  */
@@ -92,6 +105,9 @@ uint32_t bkp_read_rtc(void);
  */
 void bkp_reset(void);
 
+void bkp_write_data(enum BkpData data_index, uint16_t data);
+uint16_t bkp_read_data(enum BkpData data_index);
+
 //unimplemented functions
 void bkp_configure_tamper();
 void bkp_calibrate_lsi(void);