From 26bb798b7969af4ce0539639d0e419b11e008723 Mon Sep 17 00:00:00 2001
From: Steins7 <steinsset@gmail.com>
Date: Wed, 5 Jul 2023 23:05:03 +0200
Subject: [PATCH] Add usart's read function

---
 drivers/usart.c | 61 +++++++++++++++++++++++++++++++++++++------------
 drivers/usart.h |  4 ++--
 2 files changed, 48 insertions(+), 17 deletions(-)

diff --git a/drivers/usart.c b/drivers/usart.c
index 4822784..017df30 100644
--- a/drivers/usart.c
+++ b/drivers/usart.c
@@ -23,6 +23,7 @@ static volatile struct USART* const usart3 = (struct USART*)USART3_BASE_ADDRESS;
 void configure_usart(volatile struct USART* regs, enum UsartConfig config);
 void configure_baudrate(volatile struct USART* regs, uint32_t clock,
 		uint32_t baudrate);
+uint32_t periph_regs(enum UsartPeriph periph, volatile struct USART** regs);
 
 
 //--local variables-------------------------------------------------------------
@@ -56,24 +57,34 @@ void usart_configure(enum UsartPeriph periph, enum UsartConfig config,
 	}
 }
 
-uint8_t usart_write_byte(enum UsartPeriph periph, uint8_t byte)
+uint32_t usart_write_byte(enum UsartPeriph periph, uint8_t byte)
 {
-	switch (periph) {
-		case USART_PERIPH_1:
-			if (usart1->SR.TXE) {
-				reg_write(usart1->DR, USART_DR_DR, byte);
-				return 0;
-			} else {
-				return 1;
-			}
-
-		case USART_PERIPH_2:
-		case USART_PERIPH_3:
-		default:
-			break;
+	volatile struct USART* regs;
+	if (periph_regs(periph, &regs)) {
+		return 1;
 	}
 
-	return 1;
+	if (regs->SR.TXE) {
+		reg_write(regs->DR, USART_DR_DR, byte);
+		return 0;
+	} else {
+		return 1;
+	}
+}
+
+uint32_t usart_read_byte(enum UsartPeriph periph, uint8_t* byte)
+{
+	volatile struct USART* regs;
+	if (periph_regs(periph, &regs)) {
+		return 1;
+	}
+
+	if (regs->SR.RXNE) {
+		*byte = regs->DR.DR;
+		return 0;
+	} else {
+		return 1;
+	}
 }
 
 //--local functions-------------------------------------------------------------
@@ -167,3 +178,23 @@ void configure_baudrate(volatile struct USART* regs, uint32_t clock,
 	reg_write(regs->BRR, USART_BRR_DIV_Fraction, divider & 0xF);
 }
 
+uint32_t periph_regs(enum UsartPeriph periph, volatile struct USART** regs)
+{
+	switch (periph) {
+		case USART_PERIPH_1:
+			*regs = usart1;
+			break;
+		case USART_PERIPH_2:
+			*regs = usart2;
+			break;
+		case USART_PERIPH_3:
+			*regs = usart3;
+			break;
+		default:
+			return 1;
+			break;
+	}
+
+	return 0;
+}
+
diff --git a/drivers/usart.h b/drivers/usart.h
index 8c15f2a..c5845c1 100644
--- a/drivers/usart.h
+++ b/drivers/usart.h
@@ -42,9 +42,9 @@ void usart_configure(enum UsartPeriph periph, enum UsartConfig config,
 
 void usart_reset(enum UsartPeriph periph);
 
-uint8_t usart_write_byte(enum UsartPeriph periph, uint8_t byte);
+uint32_t usart_write_byte(enum UsartPeriph periph, uint8_t byte);
 
-uint8_t usart_read_byte(enum UsartPeriph periph, uint8_t* byte);
+uint32_t usart_read_byte(enum UsartPeriph periph, uint8_t* byte);
 
 
 #endif //_USART_H_