ESP32: Add driver support to I2C

This driver was implemented by Dong Heng <dongheng@espressif.com>
and modified to fix coding style by Alan Carvalho de Assis.

Co-authored-by: Abdelatif Guettouche <abdelatif.guettouche@gmail.com>

arch/xtensa/src/esp32/Kconfig

@@ -26,11 +26,8 @@ config ESP32_EMAC
 		No yet implemented
 
 config ESP32_I2C
-	bool "I2C"
+	bool
 	default n
-	depends on EXPERIMENTAL
-	---help---
-		No yet implemented
 
 config ESP32_I2S0
 	bool "I2S 0"
@@ -202,6 +199,20 @@ config ESP32_WIRELESS
 	---help---
 		No yet implemented
 
+config ESP32_I2C0
+	bool "I2C 0"
+	default n
+	select ESP32_I2C
+	select I2C
+	select I2C_DRIVER
+
+config ESP32_I2C1
+	bool "I2C 1"
+	default n
+	select ESP32_I2C
+	select I2C
+	select I2C_DRIVER
+
 endmenu # ESP32 Peripheral Selection
 
 menu "Memory Configuration"
@@ -308,6 +319,39 @@ endif # ESP32_UART2
 
 endmenu # UART configuration
 
+menu "I2C configuration"
+	depends on ESP32_I2C
+
+if ESP32_I2C0
+
+config ESP32_I2C0_SCLPIN
+	int "I2C0 SCL Pin"
+	default 24
+	range 0 39
+
+config ESP32_I2C0_SDAPIN
+	int "I2C0 SDA Pin"
+	default 23
+	range 0 39
+
+endif # ESP32_I2C0
+
+if ESP32_I2C1
+
+config ESP32_I2C1_SCLPIN
+	int "I2C1 SCL Pin"
+	default 26
+	range 0 39
+
+config ESP32_I2C1_SDAPIN
+	int "I2C1 SDA Pin"
+	default 25
+	range 0 39
+
+endif # ESP32_I2C1
+
+endmenu # I2C configuration
+
 menu "SPI configuration"
 	depends on ESP32_SPI
 

arch/xtensa/src/esp32/Make.defs

@@ -100,6 +100,10 @@ CHIP_CSRCS += esp32_gpio.c esp32_intdecode.c esp32_irq.c esp32_region.c
 CHIP_CSRCS += esp32_timerisr.c
 CHIP_CSRCS += esp32_user.c
 
+ifeq ($(CONFIG_ESP32_I2C),y)
+CHIP_CSRCS += esp32_i2c.c
+endif
+
 ifeq ($(CONFIG_ESP32_SPI),y)
 CHIP_CSRCS += esp32_spi.c
   ifeq ($(CONFIG_SPI_SLAVE),y)

arch/xtensa/src/esp32/esp32_i2c.h

@@ -0,0 +1,92 @@
+/****************************************************************************
+ * arch/xtensa/src/esp32/esp32_i2c.h
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#ifndef __ARCH_XTENSA_SRC_ESP32_ESP32_I2C_H
+#define __ARCH_XTENSA_SRC_ESP32_ESP32_I2C_H
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/i2c/i2c_master.h>
+
+#ifndef __ASSEMBLY__
+
+#undef EXTERN
+#if defined(__cplusplus)
+#define EXTERN extern "C"
+extern "C"
+{
+#else
+#define EXTERN extern
+#endif
+
+/****************************************************************************
+ * Public Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: esp32_i2cbus_initialize
+ *
+ * Description:
+ *   Initialize the selected I2C port. And return a unique instance of struct
+ *   struct i2c_master_s.  This function may be called to obtain multiple
+ *   instances of the interface, each of which may be set up with a
+ *   different frequency and slave address.
+ *
+ * Input Parameters:
+ *   Port number (for hardware that has multiple I2C interfaces)
+ *
+ * Returned Value:
+ *   Valid I2C device structure reference on success; a NULL on failure
+ *
+ ****************************************************************************/
+
+FAR struct i2c_master_s *esp32_i2cbus_initialize(int port);
+
+/****************************************************************************
+ * Name: esp32_i2cbus_uninitialize
+ *
+ * Description:
+ *   De-initialize the selected I2C port, and power down the device.
+ *
+ * Input Parameters:
+ *   Device structure as returned by the esp32_i2cbus_initialize()
+ *
+ * Returned Value:
+ *   OK on success, ERROR when internal reference count mismatch or dev
+ *   points to invalid hardware device.
+ *
+ ****************************************************************************/
+
+int esp32_i2cbus_uninitialize(FAR struct i2c_master_s *dev);
+
+#ifdef __cplusplus
+}
+#endif
+#undef EXTERN
+
+#endif /* __ASSEMBLY__ */
+#endif /* __ARCH_XTENSA_SRC_ESP32_ESP32_I2C_H */