drivers: bbram: stm32: reference counter for Backup Registers accesses

Use recently added SoCs functions to request access to SoC backup
domain resources These function use a reference counter to track these
request and ensure the resources are accessible as long as at least a
consumer requires access.

Fixes issue 90942.

Signed-off-by: Etienne Carriere <etienne.carriere@foss.st.com>

drivers/bbram/bbram_stm32.c

@@ -13,6 +13,8 @@
 #include <zephyr/sys/util.h>
 #include <stm32_ll_pwr.h>
 #include <stm32_ll_rtc.h>
+#include <stm32_backup_domain.h>
+
 LOG_MODULE_REGISTER(bbram, CONFIG_BBRAM_LOG_LEVEL);
 
 #define STM32_BKP_REG_BYTES		 4
@@ -66,9 +68,7 @@ static int bbram_stm32_write(const struct device *dev, size_t offset, size_t siz
 		return -EFAULT;
 	}
 
-#if defined(PWR_CR_DBP) || defined(PWR_CR1_DBP) || defined(PWR_DBPCR_DBP) || defined(PWR_DBPR_DBP)
-	LL_PWR_EnableBkUpAccess();
-#endif /* PWR_CR_DBP || PWR_CR1_DBP || PWR_DBPCR_DBP || PWR_DBPR_DBP */
+	stm32_backup_domain_enable_access();
 
 	for (size_t written = 0; written < size; written += to_copy) {
 		reg = STM32_BKP_REG(STM32_BKP_REG_INDEX(offset + written));
@@ -78,9 +78,7 @@ static int bbram_stm32_write(const struct device *dev, size_t offset, size_t siz
 		STM32_BKP_REG(STM32_BKP_REG_INDEX(offset + written)) = reg;
 	}
 
-#if defined(PWR_CR_DBP) || defined(PWR_CR1_DBP) || defined(PWR_DBPCR_DBP) || defined(PWR_DBPR_DBP)
-	LL_PWR_DisableBkUpAccess();
-#endif /* PWR_CR_DBP || PWR_CR1_DBP || PWR_DBPCR_DBP || PWR_DBPR_DBP */
+	stm32_backup_domain_disable_access();
 
 	return 0;
 }