Update UART driver API (#14839)

* Add uart_puts() and uart_gets()

* Add some docs

* Rework API

* Formatting

* Update docs/uart_driver.md

Co-authored-by: Sergey Vlasov <sigprof@gmail.com>

* Simplify a uart_write() loop

* Update platforms/avr/drivers/uart.c

Co-authored-by: Joel Challis <git@zvecr.com>

Co-authored-by: Sergey Vlasov <sigprof@gmail.com>
Co-authored-by: Joel Challis <git@zvecr.com>

2 files changed, 25 insertions, 9 deletions

diff --git a/platforms/avr/drivers/uart.c b/platforms/avr/drivers/uart.c
index c6abcb6fe0..01cf6b1fb8 100644
--- a/platforms/avr/drivers/uart.c
+++ b/platforms/avr/drivers/uart.c
@@ -100,7 +100,7 @@ void uart_init(uint32_t baud) {
 }
 
 // Transmit a byte
-void uart_putchar(uint8_t c) {
+void uart_write(uint8_t data) {
     uint8_t i;
 
     i = tx_buffer_head + 1;
@@ -110,27 +110,39 @@ void uart_putchar(uint8_t c) {
     while (tx_buffer_tail == i)
         ;  // wait until space in buffer
     // cli();
-    tx_buffer[i]   = c;
+    tx_buffer[i]   = data;
     tx_buffer_head = i;
     UCSRnB         = (1 << RXENn) | (1 << TXENn) | (1 << RXCIEn) | (1 << UDRIEn);
     // sei();
 }
 
 // Receive a byte
-uint8_t uart_getchar(void) {
-    uint8_t c, i;
+uint8_t uart_read(void) {
+    uint8_t data, i;
 
     while (rx_buffer_head == rx_buffer_tail)
         ;  // wait for character
     i = rx_buffer_tail + 1;
     if (i >= RX_BUFFER_SIZE) i = 0;
-    c              = rx_buffer[i];
+    data           = rx_buffer[i];
     rx_buffer_tail = i;
-    return c;
+    return data;
+}
+
+void uart_transmit(const uint8_t *data, uint16_t length) {
+    for (uint16_t i = 0; i < length; i++) {
+        uart_write(data[i]);
+    }
+}
+
+void uart_receive(uint8_t *data, uint16_t length) {
+    for (uint16_t i = 0; i < length; i++) {
+        data[i] = uart_read();
+    }
 }
 
 // Return whether the number of bytes waiting in the receive buffer is nonzero.
-// Call this before uart_getchar() to check if it will need
+// Call this before uart_read() to check if it will need
 // to wait for a byte to arrive.
 bool uart_available(void) {
     uint8_t head, tail;
diff --git a/platforms/avr/drivers/uart.h b/platforms/avr/drivers/uart.h
index 602eb3d8b0..9cb7652b08 100644
--- a/platforms/avr/drivers/uart.h
+++ b/platforms/avr/drivers/uart.h
@@ -28,8 +28,12 @@
 
 void uart_init(uint32_t baud);
 
-void uart_putchar(uint8_t c);
+void uart_write(uint8_t data);
 
-uint8_t uart_getchar(void);
+uint8_t uart_read(void);
+
+void uart_transmit(const char *data, uint16_t length);
+
+void uart_receive(char *data, uint16_t length);
 
 bool uart_available(void);