libraries: SPI: Initial SPI implementation

- Tested controller mode on beagleconnect_freedom

Signed-off-by: Ayush Singh <ayushdevel1325@gmail.com>

Author: Ayush1325

libraries/CMakeLists.txt

@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: Apache-2.0
 
 add_subdirectory(Wire)
+add_subdirectory(SPI)

libraries/SPI/CMakeLists.txt

@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: Apache-2.0
+zephyr_include_directories(.)
+
+if(NOT DEFINED ARDUINO_BUILD_PATH)
+	zephyr_sources_ifdef(CONFIG_SPI SPI.cpp)
+endif()

libraries/SPI/SPI.cpp

@@ -0,0 +1,100 @@
+/*
+ * Copyright (c) 2024 Ayush Singh <ayush@beagleboard.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "SPI.h"
+#include <zephyr/kernel.h>
+
+uint8_t SPCR;
+
+arduino::ZephyrSPI::ZephyrSPI(const struct device *spi) : spi_dev(spi) {}
+
+uint8_t arduino::ZephyrSPI::transfer(uint8_t data) {
+  int ret;
+  uint8_t rx;
+  const struct spi_buf tx_buf = {.buf = &data, .len = sizeof(data)};
+  const struct spi_buf_set tx_buf_set = {
+      .buffers = &tx_buf,
+      .count = 1,
+  };
+  const struct spi_buf rx_buf = {.buf = &rx, .len = sizeof(rx)};
+  const struct spi_buf_set rx_buf_set = {
+      .buffers = &rx_buf,
+      .count = 1,
+  };
+
+  ret = spi_transceive(spi_dev, &config, &tx_buf_set, &rx_buf_set);
+  if (ret < 0) {
+    return 0;
+  }
+
+  return rx;
+}
+
+uint16_t arduino::ZephyrSPI::transfer16(uint16_t data) {
+  int ret;
+  uint16_t rx;
+  const struct spi_buf tx_buf = {.buf = &data, .len = sizeof(data)};
+  const struct spi_buf_set tx_buf_set = {
+      .buffers = &tx_buf,
+      .count = 1,
+  };
+  const struct spi_buf rx_buf = {.buf = &rx, .len = sizeof(rx)};
+  const struct spi_buf_set rx_buf_set = {
+      .buffers = &rx_buf,
+      .count = 1,
+  };
+
+  ret = spi_transceive(spi_dev, &config, &tx_buf_set, &rx_buf_set);
+  if (ret < 0) {
+    return 0;
+  }
+
+  return rx;
+}
+
+void arduino::ZephyrSPI::transfer(void *buf, size_t count) {
+  int ret;
+  const struct spi_buf tx_buf = {.buf = &buf, .len = count};
+  const struct spi_buf_set tx_buf_set = {
+      .buffers = &tx_buf,
+      .count = 1,
+  };
+
+  ret = spi_write(spi_dev, &config, &tx_buf_set);
+  if (ret < 0) {
+    return;
+  }
+
+  ret = spi_read(spi_dev, &config, &tx_buf_set);
+  if (ret < 0) {
+    return;
+  }
+}
+
+void arduino::ZephyrSPI::usingInterrupt(int interruptNumber) {}
+
+void arduino::ZephyrSPI::notUsingInterrupt(int interruptNumber) {}
+
+void arduino::ZephyrSPI::beginTransaction(SPISettings settings) {
+  memset(&config, 0, sizeof(config));
+  config.frequency = settings.getClockFreq();
+  config.operation = ((settings.getBitOrder() ^ 1) << 4) |
+                     (settings.getDataMode() << 1) | ((SPCR >> MSTR) & 1) |
+                     SPI_WORD_SET(8);
+}
+
+void arduino::ZephyrSPI::endTransaction(void) { spi_release(spi_dev, &config); }
+
+void arduino::ZephyrSPI::attachInterrupt() {}
+
+void arduino::ZephyrSPI::detachInterrupt() {}
+
+void arduino::ZephyrSPI::begin() {}
+
+void arduino::ZephyrSPI::end() {}
+
+arduino::ZephyrSPI
+    SPI(DEVICE_DT_GET(DT_PHANDLE_BY_IDX(DT_PATH(zephyr_user), spis, 0)));

libraries/SPI/SPI.h

@@ -0,0 +1,59 @@
+/*
+ * Copyright (c) 2024 Ayush Singh <ayush@beagleboard.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include <Arduino.h>
+#include <api/HardwareSPI.h>
+#include <zephyr/drivers/spi.h>
+
+#define SPR0 0
+#define SPR1 1
+#define CPHA 2
+#define CPOL 3
+#define MSTR 4
+#define DORD 5
+#define SPE 6
+#define SPIE 7
+
+namespace arduino {
+class ZephyrSPI : public HardwareSPI {
+public:
+  ZephyrSPI(const struct device *spi);
+
+  virtual uint8_t transfer(uint8_t data);
+  virtual uint16_t transfer16(uint16_t data);
+  virtual void transfer(void *buf, size_t count);
+
+  // Transaction Functions
+  virtual void usingInterrupt(int interruptNumber);
+  virtual void notUsingInterrupt(int interruptNumber);
+  virtual void beginTransaction(SPISettings settings);
+  virtual void endTransaction(void);
+
+  // SPI Configuration methods
+  virtual void attachInterrupt();
+  virtual void detachInterrupt();
+
+  virtual void begin();
+  virtual void end();
+
+private:
+  const struct device *spi_dev;
+	struct spi_config config;
+};
+
+} // namespace arduino
+
+extern arduino::ZephyrSPI SPI;
+/* Serial Peripheral Control Register */
+extern uint8_t SPCR;
+
+using arduino::SPI_MODE0;
+using arduino::SPI_MODE1;
+using arduino::SPI_MODE2;
+using arduino::SPI_MODE3;
+using arduino::SPISettings;