stm32/usart: Implemented a function to get the current stop bits setting for a USART

include/libopencm3/stm32/common/usart_common_all.h

@@ -102,6 +102,7 @@ void usart_set_baudrate(uint32_t usart, uint32_t baud);
 void usart_set_databits(uint32_t usart, uint32_t bits);
 uint32_t usart_get_databits(uint32_t usart);
 void usart_set_stopbits(uint32_t usart, uint32_t stopbits);
+uint32_t usart_get_stopbits(uint32_t usart);
 void usart_set_parity(uint32_t usart, uint32_t parity);
 void usart_set_mode(uint32_t usart, uint32_t mode);
 void usart_set_flow_control(uint32_t usart, uint32_t flowcontrol);

lib/stm32/common/usart_common_all.c

@@ -135,6 +135,22 @@ void usart_set_stopbits(uint32_t usart, uint32_t stopbits)
 	USART_CR2(usart) = reg32;
 }
 
+/*---------------------------------------------------------------------------*/
+/** @brief USART Get Stop Bit(s).
+
+The stop bits are specified as 0.5, 1, 1.5 or 2.
+
+@param[in] usart unsigned 32 bit. USART block register address base @ref
+usart_reg_base
+@returns unsigned 32 bit Stop bits @ref usart_cr2_stopbits.
+*/
+
+uint32_t usart_get_stopbits(uint32_t usart)
+{
+	const uint32_t reg32 = USART_CR2(usart);
+	return reg32 & USART_CR2_STOPBITS_MASK;
+}
+
 /*---------------------------------------------------------------------------*/
 /** @brief USART Set Parity.