uart: uart_set_pin function will now use IOMUX whenever possible

By using IOMUX instead of GPIO Matrix for UART, it is now possible
on ESP32 boards to use the UART as a wake up source even if it is
not used as a console.
For other boards where this issue was not present, using IOMUX has
the advantage to be faster than using GPIO matrix, so a highest
baudrate can be used

components/soc/esp32/include/soc/uart_pins.h

@@ -0,0 +1,53 @@
+// Copyright 2015-2021 Espressif Systems (Shanghai) PTE LTD
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "soc/io_mux_reg.h"
+
+/* Specify the number of pins for UART */
+#define SOC_UART_PINS_COUNT  (4)
+
+/* Specify the GPIO pin number for each UART signal in the IOMUX */
+#define U0TXD_GPIO_NUM  (1)
+#define U0RXD_GPIO_NUM  (3)
+#define U0CTS_GPIO_NUM  (19)
+#define U0RTS_GPIO_NUM  (22)
+
+#define U1TXD_GPIO_NUM  (10)
+#define U1RXD_GPIO_NUM  (9)
+#define U1CTS_GPIO_NUM  (6)
+#define U1RTS_GPIO_NUM  (11)
+
+#define U2TXD_GPIO_NUM  (17)
+#define U2RXD_GPIO_NUM  (16)
+#define U2CTS_GPIO_NUM  (8)
+#define U2RTS_GPIO_NUM  (7)
+
+/* The following defines are necessary for reconfiguring the UART
+ * to use IOMUX, at runtime. */
+#define U0TXD_MUX_FUNC  (FUNC_U0TXD_U0TXD)
+#define U0RXD_MUX_FUNC  (FUNC_U0RXD_U0RXD)
+#define U0RTS_MUX_FUNC  (FUNC_GPIO22_U0RTS)
+#define U0CTS_MUX_FUNC  (FUNC_GPIO19_U0CTS)
+
+#define U1TXD_MUX_FUNC  (FUNC_SD_DATA3_U1TXD)
+#define U1RXD_MUX_FUNC  (FUNC_SD_DATA2_U1RXD)
+#define U1RTS_MUX_FUNC  (FUNC_SD_CMD_U1RTS)
+#define U1CTS_MUX_FUNC  (FUNC_SD_CLK_U1CTS)
+
+#define U2TXD_MUX_FUNC  (FUNC_GPIO17_U2TXD)
+#define U2RXD_MUX_FUNC  (FUNC_GPIO16_U2RXD)
+#define U2RTS_MUX_FUNC  (FUNC_SD_DATA0_U2RTS)
+#define U2CTS_MUX_FUNC  (FUNC_SD_DATA1_U2CTS)

components/soc/esp32/uart_periph.c

@@ -19,27 +19,104 @@
 */
 const uart_signal_conn_t uart_periph_signal[SOC_UART_NUM] = {
     {
-        .tx_sig = U0TXD_OUT_IDX,
-        .rx_sig = U0RXD_IN_IDX,
-        .rts_sig = U0RTS_OUT_IDX,
-        .cts_sig = U0CTS_IN_IDX,
+        .pins = {
+            [SOC_UART_TX_PIN_IDX] = {
+                .default_gpio = U0TXD_GPIO_NUM,
+                .iomux_func = U0TXD_MUX_FUNC,
+                .input = 0,
+                .signal = U0TXD_OUT_IDX,
+            },
+
+            [SOC_UART_RX_PIN_IDX] = {
+                .default_gpio = U0RXD_GPIO_NUM,
+                .iomux_func = U0RXD_MUX_FUNC,
+                .input = 1,
+                .signal = U0RXD_IN_IDX,
+            },
+
+            [SOC_UART_RTS_PIN_IDX] = {
+                .default_gpio = U0RTS_GPIO_NUM,
+                .iomux_func = U0RTS_MUX_FUNC,
+                .input = 0,
+                .signal = U0RTS_OUT_IDX,
+            },
+
+            [SOC_UART_CTS_PIN_IDX] = {
+                .default_gpio = U0CTS_GPIO_NUM,
+                .iomux_func = U0CTS_MUX_FUNC,
+                .input = 1,
+                .signal = U0CTS_IN_IDX,
+            }
+        },
         .irq = ETS_UART0_INTR_SOURCE,
         .module = PERIPH_UART0_MODULE,
     },
+
     {
-        .tx_sig = U1TXD_OUT_IDX,
-        .rx_sig = U1RXD_IN_IDX,
-        .rts_sig = U1RTS_OUT_IDX,
-        .cts_sig = U1CTS_IN_IDX,
+        .pins = {
+            [SOC_UART_TX_PIN_IDX] = {
+                .default_gpio = U1TXD_GPIO_NUM,
+                .iomux_func = U1TXD_MUX_FUNC,
+                .input = 0,
+                .signal = U1TXD_OUT_IDX,
+            },
+
+            [SOC_UART_RX_PIN_IDX] = {
+                .default_gpio = U1RXD_GPIO_NUM,
+                .iomux_func = U1RXD_MUX_FUNC,
+                .input = 1,
+                .signal = U1RXD_IN_IDX,
+            },
+
+            [SOC_UART_RTS_PIN_IDX] = {
+                .default_gpio = U1RTS_GPIO_NUM,
+                .iomux_func = U1RTS_MUX_FUNC,
+                .input = 0,
+                .signal = U1RTS_OUT_IDX,
+            },
+
+            [SOC_UART_CTS_PIN_IDX] = {
+                .default_gpio = U1CTS_GPIO_NUM,
+                .iomux_func = U1CTS_MUX_FUNC,
+                .input = 1,
+                .signal = U1CTS_IN_IDX,
+            },
+        },
         .irq = ETS_UART1_INTR_SOURCE,
         .module = PERIPH_UART1_MODULE,
     },
+
     {
-        .tx_sig = U2TXD_OUT_IDX,
-        .rx_sig = U2RXD_IN_IDX,
-        .rts_sig = U2RTS_OUT_IDX,
-        .cts_sig = U2CTS_IN_IDX,
+        .pins = {
+            [SOC_UART_TX_PIN_IDX] = {
+                .default_gpio = U2TXD_GPIO_NUM,
+                .iomux_func = U2TXD_MUX_FUNC,
+                .input = 0,
+                .signal = U2TXD_OUT_IDX,
+            },
+
+            [SOC_UART_RX_PIN_IDX] = {
+                .default_gpio = U2RXD_GPIO_NUM,
+                .iomux_func = U2RXD_MUX_FUNC,
+                .input = 1,
+                .signal = U2RXD_IN_IDX,
+            },
+
+            [SOC_UART_RTS_PIN_IDX] = {
+                .default_gpio = U2RTS_GPIO_NUM,
+                .iomux_func = U2RTS_MUX_FUNC,
+                .input = 0,
+                .signal = U2RTS_OUT_IDX,
+            },
+
+            [SOC_UART_CTS_PIN_IDX] = {
+                .default_gpio = U2CTS_GPIO_NUM,
+                .iomux_func = U2CTS_MUX_FUNC,
+                .input = 1,
+                .signal = U2CTS_IN_IDX,
+            }
+        },
         .irq = ETS_UART2_INTR_SOURCE,
         .module = PERIPH_UART2_MODULE,
-    },
+    }
 };