From ebe9b37444506733db2be56ed628c8033d94fb28 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Dauphin?= <astralien3000@yahoo.fr>
Date: Mon, 27 Mar 2017 15:50:43 +0200
Subject: [PATCH] drivers/uart_half_duplex: initial support
---
drivers/Makefile.dep | 6 +
drivers/Makefile.include | 3 +
drivers/uart_half_duplex/Makefile | 1 +
.../include/uart_half_duplex.h | 143 ++++++++++++++++++
drivers/uart_half_duplex/uart_half_duplex.c | 109 +++++++++++++
5 files changed, 262 insertions(+)
create mode 100644 drivers/uart_half_duplex/Makefile
create mode 100644 drivers/uart_half_duplex/include/uart_half_duplex.h
create mode 100644 drivers/uart_half_duplex/uart_half_duplex.c
diff --git a/drivers/Makefile.dep b/drivers/Makefile.dep
index 71783893fa..c2a8dd7d67 100644
--- a/drivers/Makefile.dep
+++ b/drivers/Makefile.dep
@@ -203,3 +203,9 @@ ifneq (,$(filter xbee,$(USEMODULE)))
USEMODULE += xtimer
USEMODULE += netif
endif
+
+ifneq (,$(filter uart_half_duplex,$(USEMODULE)))
+ FEATURES_REQUIRED += periph_gpio
+ FEATURES_REQUIRED += periph_uart
+ USEMODULE += xtimer
+endif
diff --git a/drivers/Makefile.include b/drivers/Makefile.include
index 971e91089b..849e6cbf3d 100644
--- a/drivers/Makefile.include
+++ b/drivers/Makefile.include
@@ -106,3 +106,6 @@ endif
ifneq (,$(filter adxl345,$(USEMODULE)))
USEMODULE_INCLUDES += $(RIOTBASE)/drivers/adxl345/include
endif
+ifneq (,$(filter uart_half_duplex,$(USEMODULE)))
+ USEMODULE_INCLUDES += $(RIOTBASE)/drivers/uart_half_duplex/include
+endif
diff --git a/drivers/uart_half_duplex/Makefile b/drivers/uart_half_duplex/Makefile
new file mode 100644
index 0000000000..48422e909a
--- /dev/null
+++ b/drivers/uart_half_duplex/Makefile
@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base
diff --git a/drivers/uart_half_duplex/include/uart_half_duplex.h b/drivers/uart_half_duplex/include/uart_half_duplex.h
new file mode 100644
index 0000000000..7e694d75f5
--- /dev/null
+++ b/drivers/uart_half_duplex/include/uart_half_duplex.h
@@ -0,0 +1,143 @@
+/*
+ * Copyright (C) 2017 Inria
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @defgroup drivers_uart_half_duplex half-duplex UART Driver
+ * @ingroup drivers_actuators
+ *
+ * This module contains drivers for UART half-duplex communication bus.
+ * It needs to manage the communication direction by enabling or disabling TX.
+ *
+ * @{
+ *
+ * @file
+ * @brief Interface definition for half-duplex UART driver
+ *
+ * @author Loïc Dauphin <loic.dauphin@inria.fr>
+ */
+
+#ifndef UART_HALF_DUPLEX_H
+#define UART_HALF_DUPLEX_H
+
+#include <stdlib.h>
+
+#include "periph/uart.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef UART_HALF_DUPLEX_DEFAULT_TIMEOUT_US
+#define UART_HALF_DUPLEX_DEFAULT_TIMEOUT_US (20000LU) /**< Default recv timeout (in microseconds) */
+#endif
+
+/**
+ * @brief half-duplex UART direction management method type
+ */
+typedef int uart_half_duplex_dir_t;
+
+#define UART_HALF_DUPLEX_DIR_NONE (0) /**< Don't manage direction */
+
+#define UART_HALF_DUPLEX_DIR_PIN_SET(pin) (((pin + 1) << 1)) /**< pin set enables TX */
+#define UART_HALF_DUPLEX_DIR_PIN_CLEAR(pin) (((pin + 1) << 1) | 1) /**< pin clear enables TX */
+
+/**
+ * @brief Configuration for half-duplex UART
+ */
+typedef struct {
+ uart_t uart; /**< the half-duplex UART bus to use */
+ uint32_t baudrate; /**< the baudrate to use */
+ uart_half_duplex_dir_t dir; /**< the direction management method */
+} uart_half_duplex_params_t;
+
+/**
+ * @brief Descriptor struct for half-duplex UART
+ */
+typedef struct {
+ uint8_t *buffer; /**< the buffer used for TX and RX */
+ size_t size; /**< the number of available elements for TX/RX */
+ size_t buffer_max_size; /**< the buffer size */
+ uint32_t timeout_us; /**< the maximum duration (in microseconds) for waiting data */
+ uart_half_duplex_params_t params; /**< the half-duplex UART configuration */
+} uart_half_duplex_t;
+
+/**
+ * @brief Possible UART_HALF_DUPLEX return values
+ */
+enum {
+ UART_HALF_DUPLEX_OK = UART_OK, /**< everything in order */
+ UART_HALF_DUPLEX_NODEV = UART_NODEV, /**< invalid UART device given */
+ UART_HALF_DUPLEX_NOBAUD = UART_NOBAUD, /**< given baudrate is not applicable */
+ UART_HALF_DUPLEX_INTERR = UART_INTERR, /**< all other internal errors */
+ UART_HALF_DUPLEX_NOMODE = UART_NOMODE, /**< given mode is not applicable */
+ UART_HALF_DUPLEX_NOBUFF = -5 /**< invalid buffer given */
+};
+
+/**
+ * @brief Initialize the half-duplex UART bus to communicate with devices
+ *
+ * @param[out] dev the device
+ * @param[in] buffer the buffer used for TX and RX
+ * @param[in] buffer_max_size the buffer size
+ * @param[in] params the initialization parameters
+ *
+ * @return UART_HALF_DUPLEX_OK if everything is in order
+ * @return UART_HALF_DUPLEX_NODEV if invalid UART device was given
+ * @return UART_HALF_DUPLEX_NOBAUD if given baudrate is not applicable
+ * @return UART_HALF_DUPLEX_INTERR if an other internal error occured
+ * @return UART_HALF_DUPLEX_NOMODE if the given mode is not applicable
+ * @return UART_HALF_DUPLEX_NOBUFF if an invalid buffer was given
+ */
+int uart_half_duplex_init(uart_half_duplex_t *dev, uint8_t *buffer, size_t buffer_max_size, const uart_half_duplex_params_t *params);
+
+/**
+ * @brief Set the half-duplex UART bus in TX mode
+ *
+ * @param[in] dev the device
+ */
+static inline void uart_half_duplex_set_tx(uart_half_duplex_t *dev)
+{
+ dev->size = dev->buffer_max_size;
+}
+
+/**
+ * @brief Set the half-duplex UART bus in RX mode
+ *
+ * @param[in] dev the device
+ */
+static inline void uart_half_duplex_set_rx(uart_half_duplex_t *dev)
+{
+ dev->size = 0;
+}
+
+/**
+ * @brief Send the data contained in the driver's buffer
+ *
+ * @param[in] dev the device
+ * @param[in] size the number of characters to send
+ *
+ * @return the number of characters actually sent
+ */
+size_t uart_half_duplex_send(uart_half_duplex_t *dev, size_t size);
+
+/**
+ * @brief Recv data an fill the driver's buffer
+ *
+ * @param[in] dev the device
+ * @param[in] size the number of characters to receive
+ *
+ * @return the number of characters actually received
+ */
+size_t uart_half_duplex_recv(uart_half_duplex_t *dev, size_t size);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/** @} */
diff --git a/drivers/uart_half_duplex/uart_half_duplex.c b/drivers/uart_half_duplex/uart_half_duplex.c
new file mode 100644
index 0000000000..7147899b77
--- /dev/null
+++ b/drivers/uart_half_duplex/uart_half_duplex.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2017 Inria
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @ingroup drivers_uart_half_duplex
+ * @{
+ *
+ * @file
+ * @brief Driver implementation for half-duplex UART devices
+ *
+ * @author Loïc Dauphin <loic.dauphin@inria.fr>
+ *
+ * @}
+ */
+
+#include "uart_half_duplex.h"
+
+#include "periph/uart.h"
+#include "periph/gpio.h"
+#include "xtimer.h"
+
+#define IS_SET(dir) ((dir & 1) == 0)
+#define IS_CLEAR(dir) ((dir & 1) == 1)
+
+#define IS_PIN(dir) (dir >= UART_HALF_DUPLEX_DIR_PIN_SET(0))
+#define GET_PIN(dir) ((dir >> 1) - 1)
+
+static inline void _enable_tx(uart_half_duplex_dir_t dir)
+{
+ if (IS_PIN(dir)) {
+ if (IS_SET(dir)) {
+ gpio_set(GET_PIN(dir));
+ return;
+ }
+ if (IS_CLEAR(dir)) {
+ gpio_clear(GET_PIN(dir));
+ return;
+ }
+ }
+}
+
+static inline void _disable_tx(uart_half_duplex_dir_t dir)
+{
+ if (IS_PIN(dir)) {
+ if (IS_SET(dir)) {
+ gpio_clear(GET_PIN(dir));
+ return;
+ }
+ if (IS_CLEAR(dir)) {
+ gpio_set(GET_PIN(dir));
+ return;
+ }
+ }
+}
+
+static void _rx_cb(void* data, uint8_t c)
+{
+ uart_half_duplex_t *dev = data;
+ if (dev->size < dev->buffer_max_size) {
+ dev->buffer[dev->size++] = c;
+ }
+}
+
+int uart_half_duplex_init(uart_half_duplex_t *dev, uint8_t *buffer, size_t buffer_max_size, const uart_half_duplex_params_t *params)
+{
+ if (buffer == NULL || buffer_max_size <= 7) {
+ return UART_HALF_DUPLEX_NOBUFF;
+ }
+
+ dev->buffer = buffer;
+ dev->buffer_max_size = buffer_max_size;
+ dev->params = *params;
+ dev->timeout_us = UART_HALF_DUPLEX_DEFAULT_TIMEOUT_US;
+
+ if (IS_PIN(dev->params.dir)) {
+ gpio_init(GET_PIN(dev->params.dir), GPIO_OUT);
+ }
+
+ int ret = uart_init(dev->params.uart, dev->params.baudrate, _rx_cb, dev);
+
+ _disable_tx(dev->params.dir);
+ uart_half_duplex_set_rx(dev);
+
+ return ret;
+}
+
+size_t uart_half_duplex_send(uart_half_duplex_t *dev, size_t size)
+{
+ _enable_tx(dev->params.dir);
+ uart_write(dev->params.uart, dev->buffer, size);
+ _disable_tx(dev->params.dir);
+ return size;
+}
+
+size_t uart_half_duplex_recv(uart_half_duplex_t *dev, size_t size)
+{
+ const uint32_t begin = xtimer_now_usec();
+ while (xtimer_now_usec() - begin < dev->timeout_us) {
+ if (dev->size >= size) {
+ break;
+ }
+ }
+ return dev->size;
+}
--
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