From 0bac148e0a8a87e2336faa4d5681f354bb9590cf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Franz=20H=C3=B6pfinger?= <franz.hoepfinger@fliegl.com>
Date: Sun, 18 Aug 2024 22:53:39 +0200
Subject: [PATCH] Add ESP_PLATFORM support for UART driver selection

- Add conditional compilation for ESP_PLATFORM to include UART driver headers
- Modify connection flags based on platform
- Implement UART driver selection based on device number
---
 src/modbus-rtu.c | 29 +++++++++++++++++++++++++++++
 src/modbus.c     |  3 +++
 2 files changed, 32 insertions(+)

diff --git a/src/modbus-rtu.c b/src/modbus-rtu.c
index b7749230c..e969aab10 100644
--- a/src/modbus-rtu.c
+++ b/src/modbus-rtu.c
@@ -26,6 +26,12 @@
 #include <linux/serial.h>
 #endif
 
+#if defined(ESP_PLATFORM)    
+#include "driver/uart_vfs.h"
+#include "driver/uart.h"
+#endif    
+
+
 /* Table of CRC values for high-order byte */
 static const uint8_t table_crc_hi[] = {
     0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,
@@ -641,7 +647,11 @@ static int _modbus_rtu_connect(modbus_t *ctx)
 
        Timeouts are ignored in canonical input mode or when the
        NDELAY option is set on the file via open or fcntl */
+#if defined(ESP_PLATFORM)       
+    flags = O_RDWR;
+#else
     flags = O_RDWR | O_NOCTTY | O_NDELAY | O_EXCL;
+#endif
 #ifdef O_CLOEXEC
     flags |= O_CLOEXEC;
 #endif
@@ -656,6 +666,25 @@ static int _modbus_rtu_connect(modbus_t *ctx)
         }
         return -1;
     }
+#if defined(ESP_PLATFORM)    
+    // We have a driver now installed so set up the read/write functions to use driver also.
+    switch(ctx_rtu->device[10]) { //extract from /dev/uart/1
+    case '0':
+    	uart_vfs_dev_use_driver(UART_NUM_0);
+    break;
+    case '1':
+    	uart_vfs_dev_use_driver(UART_NUM_1);
+    break;
+#if SOC_UART_HP_NUM > 2
+    case '2':
+    	uart_vfs_dev_use_driver(UART_NUM_2);
+    break;
+#endif // SOC_UART_HP_NUM > 2
+	default:
+		return -1;
+	break;
+    }
+#endif    
 
     /* Save */
     tcgetattr(ctx->s, &ctx_rtu->old_tios);
diff --git a/src/modbus.c b/src/modbus.c
index 5a9b86783..1e8b5996c 100644
--- a/src/modbus.c
+++ b/src/modbus.c
@@ -97,6 +97,8 @@ static void _sleep_response_timeout(modbus_t *ctx)
 #ifdef _WIN32
     /* usleep doesn't exist on Windows */
     Sleep((ctx->response_timeout.tv_sec * 1000) + (ctx->response_timeout.tv_usec / 1000));
+#elif (ESP_PLATFORM)
+	usleep((ctx->response_timeout.tv_sec * 1000) + (ctx->response_timeout.tv_usec / 1000));
 #else
     /* usleep source code */
     struct timespec request, remaining;
@@ -494,6 +496,7 @@ int _modbus_receive_msg(modbus_t *ctx, uint8_t *msg, msg_type_t msg_type)
                     step = _STEP_META;
                     break;
                 } /* else switches straight to the next step */
+                // ... falls through ...
             case _STEP_META:
                 length_to_read = compute_data_length_after_meta(ctx, msg, msg_type);
                 if ((msg_length + length_to_read) > ctx->backend->max_adu_length) {