/**
 * @file spi.h
 * @brief Header for SPI bus driver (full-duplex transfer with CS control)
 * @author Kevin Thomas
 * @date 2025
 *
 * MIT License
 *
 * Copyright (c) 2025 Kevin Thomas
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef SPI_H
#define SPI_H

#include <stdint.h>
#include <stdbool.h>

/**
 * @brief Initialize an SPI peripheral in master mode
 *
 * Configures the SPI instance at the requested baud rate, assigns GPIO
 * alternate functions for MOSI, MISO, and SCK, and configures the chip
 * select pin as a GPIO output deasserted (high) by default.
 *
 * @param port    SPI port number (0 for spi0, 1 for spi1)
 * @param mosi    GPIO pin number for MOSI (controller TX)
 * @param miso    GPIO pin number for MISO (controller RX)
 * @param sck     GPIO pin number for SCK (clock)
 * @param cs      GPIO pin number for chip select (active-low)
 * @param baud_hz Desired SPI clock frequency in Hz (e.g. 1000000 for 1 MHz)
 */
void spi_driver_init(uint8_t port, uint32_t mosi, uint32_t miso,
                     uint32_t sck, uint32_t cs, uint32_t baud_hz);

/**
 * @brief Assert the chip-select line (drive CS low)
 *
 * @param cs GPIO pin number of the chip-select output
 */
void spi_driver_cs_select(uint32_t cs);

/**
 * @brief Deassert the chip-select line (drive CS high)
 *
 * @param cs GPIO pin number of the chip-select output
 */
void spi_driver_cs_deselect(uint32_t cs);

/**
 * @brief Perform a full-duplex SPI transfer
 *
 * Sends @p len bytes from @p tx while simultaneously receiving @p len bytes
 * into @p rx. Both buffers must hold at least @p len bytes. The caller is
 * responsible for asserting and deasserting CS around this call.
 *
 * @param port SPI port number (0 for spi0, 1 for spi1)
 * @param tx   Pointer to the transmit buffer (must be @p len bytes)
 * @param rx   Pointer to the receive buffer  (must be @p len bytes)
 * @param len  Number of bytes to transfer
 */
void spi_driver_transfer(uint8_t port, const uint8_t *tx, uint8_t *rx,
                         uint32_t len);

#endif // SPI_H