bsp/aarch64/raspberrypi: Add I2C Support

- Implements polling-based I2C communication.
- Supports three independent I2C master controllers.
- Adds support for 10-bit addressing mode.

bsps/aarch64/raspberrypi/include/bsp/raspberrypi-i2c.h

@@ -0,0 +1,92 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @ingroup raspberrypi_4_i2c
+ *
+ * @brief Raspberry Pi specific I2C definitions.
+ */
+
+/*
+ * Copyright (C) 2025 Shaunak Datar
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef LIBBSP_AARCH64_RASPBERRYPI_I2C_H
+#define LIBBSP_AARCH64_RASPBERRYPI_I2C_H
+
+#include <bsp/raspberrypi.h>
+#include <bsp/rpi-gpio.h>
+#include <bsp/utility.h>
+#include <dev/i2c/i2c.h>
+
+/**
+ * @brief I2C controller instances on Raspberry Pi 4.
+ */
+typedef enum {
+  /**
+   * @brief BSC Master 0 (GPIO 0/1)
+   */
+  raspberrypi_bscm0,
+
+  /**
+   * @brief BSC Master 1 (GPIO 2/3)
+   */
+  raspberrypi_bscm1,
+
+  /**
+   * @brief BSC Master 3 (GPIO 4/5)
+   */
+  raspberrypi_bscm3,
+
+  /**
+   * @brief BSC Master 4 (GPIO 6/7)
+   */
+  raspberrypi_bscm4,
+
+  /**
+   * @brief BSC Master 5 (GPIO 10/11)
+   */
+  raspberrypi_bscm5,
+
+  /**
+   * @brief BSC Master 6 (GPIO 22/23)
+   */
+  raspberrypi_bscm6
+} raspberrypi_bsc_masters;
+
+/**
+ * @brief Initialize the I2C bus for a specified master.
+ *
+ * @param device The BSC master to initialize.
+ * @param bus_clock The desired bus clock frequency in Hz.
+ *
+ * @return RTEMS status code indicating success or failure.
+ */
+rtems_status_code rpi_i2c_init(
+  raspberrypi_bsc_masters device,
+  uint32_t                bus_clock
+);
+
+#endif /* LIBBSP_AARCH64_RASPBERRYPI_I2C_H */

bsps/aarch64/raspberrypi/include/bsp/raspberrypi.h

@@ -282,7 +282,6 @@
 #define BCM2711_SPI4_BASE ( RPI_PERIPHERAL_BASE + 0x204800 )
 #define BCM2711_SPI5_BASE ( RPI_PERIPHERAL_BASE + 0x204A00 )
 #define BCM2711_SPI6_BASE ( RPI_PERIPHERAL_BASE + 0x204C00 )
-
 /** @} */
 
 /**
@@ -290,7 +289,6 @@
  *
  * @{
  */
-
 #define BCM2711_CM_PWM_BASE ( RPI_PERIPHERAL_BASE + 0x00101000 )
 #define BCM2711_CM_PWM_CTL 0xA0
 #define BCM2711_CM_PWM_DIV 0xA4
@@ -299,7 +297,6 @@
 #define CM_PWM_CTL_BUSY BSP_BIT32( 7 )
 #define CM_PWM_CTL_ENAB BSP_BIT32( 4 )
 #define CM_PWM_DIV_MASK 0xFFF
-
 /** @} */
 
 /**
@@ -307,7 +304,6 @@
  *
  * @{
  */
-
 #define BCM2711_PWM0_BASE ( RPI_PERIPHERAL_BASE + 0x0020C000 )
 #define BCM2711_PWM1_BASE ( RPI_PERIPHERAL_BASE + 0x0020C800 )
 #define BCM2711_PWM_CONTROL 0x00
@@ -318,7 +314,30 @@
 #define BCM2711_PWM_FIFO 0x18
 #define BCM2711_PWM_RNG2 0x20
 #define BCM2711_PWM_DAT2 0x24
+/** @} */
 
+/**
+ * @name I2C Registers
+ *
+ * @{
+ */
+#define BCM2711_I2C0_BASE ( RPI_PERIPHERAL_BASE + 0x00205000 )
+#define BCM2711_I2C1_BASE ( RPI_PERIPHERAL_BASE + 0x00804000 )
+#define BCM2711_I2C3_BASE ( RPI_PERIPHERAL_BASE + 0x00205600 )
+#define BCM2711_I2C4_BASE ( RPI_PERIPHERAL_BASE + 0x00205800 )
+#define BCM2711_I2C5_BASE ( RPI_PERIPHERAL_BASE + 0x00205a80 )
+#define BCM2711_I2C6_BASE ( RPI_PERIPHERAL_BASE + 0x00205c00 )
+#define BCM2711_I2C_CONTROL 0x0
+#define BCM2711_I2C_STATUS 0x4
+#define BCM2711_I2C_DLEN 0x8
+#define BCM2711_I2C_SLAVE_ADDRESS 0xc
+#define BCM2711_I2C_FIFO 0x10
+#define BCM2711_I2C_DIV 0x14
+#define BCM2711_DELAY 0x18
+#define BCM2711_I2C_CLKT 0x1c
+#define BCM2711_I2C_FIFO_MASK 0xFF
+#define BCM2711_I2C_DLEN_MASK 0xFFFF
+#define BCM2711_10_BIT_ADDR_MASK 0x78
 /** @} */
 
 /**

spec/build/bsps/aarch64/raspberrypi/bspraspberrypi4.yml

@@ -67,6 +67,8 @@ links:
   uid: objwatchdog
 - role: build-dependency
   uid: objpwm
+- role: build-dependency
+  uid: obji2c
 source:
 - bsps/aarch64/raspberrypi/fdt/bsp_fdt.c
 - bsps/aarch64/raspberrypi/fdt/rpi4b_dtb.c

spec/build/bsps/aarch64/raspberrypi/obji2c.yml

@@ -0,0 +1,17 @@
+SPDX-License-Identifier: CC-BY-SA-4.0 OR BSD-2-Clause
+build-type: objects
+cflags: []
+copyrights:
+- Copyright (C) 2025 Shaunak Datar
+cppflags: []
+cxxflags: []
+enabled-by: true
+includes: []
+install:
+- destination: ${BSP_INCLUDEDIR}/bsp
+  source:
+  - bsps/aarch64/raspberrypi/include/bsp/raspberrypi-i2c.h
+links: []
+source:
+- bsps/aarch64/raspberrypi/i2c/raspberrypi-i2c.c
+type: build