STM32: Add LP_TICKER and US_TICKER optimisation define

Author: jeromecoutant

targets/TARGET_STM/device.h

@@ -37,4 +37,7 @@
 
 #include "objects.h"
 
+#include "us_ticker_defines.h"
+#include "lp_ticker_defines.h"
+
 #endif

targets/TARGET_STM/lp_ticker_defines.h

@@ -0,0 +1,41 @@
+/* mbed Microcontroller Library
+ * SPDX-License-Identifier: BSD-3-Clause
+ ******************************************************************************
+ *
+ * Copyright (c) 2015-2021 STMicroelectronics.
+ * All rights reserved.
+ *
+ * This software component is licensed by ST under BSD 3-Clause license,
+ * the "License"; You may not use this file except in compliance with the
+ * License. You may obtain a copy of the License at:
+ *                        opensource.org/licenses/BSD-3-Clause
+ *
+ ******************************************************************************
+ */
+
+#ifndef __LP_TICKER_DEFINES_H
+#define __LP_TICKER_DEFINES_H
+
+#define LP_TICKER_PERIOD_NUM    1000000
+
+#if MBED_CONF_TARGET_LPTICKER_LPTIM
+
+#if MBED_CONF_TARGET_LSE_AVAILABLE
+#define LP_TICKER_PERIOD_DEN    (LSE_VALUE / MBED_CONF_TARGET_LPTICKER_LPTIM_CLOCK)
+#else
+#define LP_TICKER_PERIOD_DEN    (LSI_VALUE / MBED_CONF_TARGET_LPTICKER_LPTIM_CLOCK)
+#endif
+#define LP_TICKER_MASK          0xFFFF      // 16 bits
+
+#else // MBED_CONF_TARGET_LPTICKER_LPTIM == 0 => Use RTC WAKEUP timer
+
+#if MBED_CONF_TARGET_LSE_AVAILABLE
+#define LP_TICKER_PERIOD_DEN    (LSE_VALUE / 4) // RTC_CLOCK / RTC_WAKEUPCLOCK_RTCCLK_DIV4
+#else
+#define LP_TICKER_PERIOD_DEN    (LSI_VALUE / 4) // RTC_CLOCK / RTC_WAKEUPCLOCK_RTCCLK_DIV4
+#endif
+#define LP_TICKER_MASK          0xFFFFFFFF  // 32 bits
+
+#endif // MBED_CONF_TARGET_LPTICKER_LPTIM
+
+#endif // __LP_TICKER_DEFINES_H