feat(eppp): Add support for UART flow control

Closes #870

Author: david-cermak

components/eppp_link/eppp_uart.c

@@ -80,12 +80,12 @@ static esp_err_t init_uart(struct eppp_uart *h, struct eppp_config_uart_s *confi
     uart_config.data_bits = UART_DATA_8_BITS;
     uart_config.parity    = UART_PARITY_DISABLE;
     uart_config.stop_bits = UART_STOP_BITS_1;
-    uart_config.flow_ctrl = UART_HW_FLOWCTRL_DISABLE;
+    uart_config.flow_ctrl = config->flow_control;
     uart_config.source_clk = UART_SCLK_DEFAULT;
 
     ESP_RETURN_ON_ERROR(uart_driver_install(h->uart_port, config->rx_buffer_size, 0, config->queue_size, &h->uart_event_queue, 0), TAG, "Failed to install UART");
     ESP_RETURN_ON_ERROR(uart_param_config(h->uart_port, &uart_config), TAG, "Failed to set params");
-    ESP_RETURN_ON_ERROR(uart_set_pin(h->uart_port, config->tx_io, config->rx_io, UART_PIN_NO_CHANGE, UART_PIN_NO_CHANGE), TAG, "Failed to set UART pins");
+    ESP_RETURN_ON_ERROR(uart_set_pin(h->uart_port, config->tx_io, config->rx_io, config->rts_io, config->cts_io), TAG, "Failed to set UART pins");
     ESP_RETURN_ON_ERROR(uart_set_rx_timeout(h->uart_port, 1), TAG, "Failed to set UART Rx timeout");
     return ESP_OK;
 }
@@ -269,6 +269,7 @@ eppp_transport_handle_t eppp_uart_init(struct eppp_config_uart_s *config)
     ESP_GOTO_ON_ERROR(init_uart(h, config), err, TAG, "Failed to init UART");
     return &h->parent;
 err:
+    free(h);
     return NULL;
 }
 

components/eppp_link/include/eppp_link.h

@@ -34,6 +34,9 @@ extern "C" {
             .rx_io = 26,        \
             .queue_size = 16,   \
             .rx_buffer_size = 1024, \
+            .rts_io = -1,       \
+            .cts_io = -1,       \
+            .flow_control = 0,  \
     },                          \
 
 #define EPPP_DEFAULT_SDIO_CONFIG() \
@@ -135,6 +138,9 @@ typedef struct eppp_config_t {
         int rx_io;
         int queue_size;
         int rx_buffer_size;
+        int rts_io;
+        int cts_io;
+        int flow_control;
     } uart;
 
     struct eppp_config_sdio_s {