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/*
* Author: Thomas Ingleby <thomas.c.ingleby@intel.com>
* Copyright (c) 2014 Intel Corporation.
*
* 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.
*/
#pragma once
/**
* @file
* @brief Serial Peripheral Interface
*
* This file defines the spi interface for libmraa. A Spi object in libmraa
* represents a spidev device. Linux spidev devices are created per spi bus and
* every chip select available on that bus has another spidev 'file'. A lot
* more information on spidev devices is available
* [here](https://www.kernel.org/doc/Documentation/spi/spidev).
*
* @snippet spi_mcp4261.c Interesting
*/
#ifdef __cplusplus
extern "C" {
#endif
#include <stdio.h>
#include <fcntl.h>
#include <stdint.h>
#include "common.h"
/**
* MRAA SPI Modes
*/
typedef enum {
MRAA_SPI_MODE0 = 0, /**< CPOL = 0, CPHA = 0, Clock idle low, data is clocked in on rising edge,
output data (change) on falling edge */
MRAA_SPI_MODE1 = 1, /**< CPOL = 0, CPHA = 1, Clock idle low, data is clocked in on falling edge,
output data (change) on rising edge */
MRAA_SPI_MODE2 = 2, /**< CPOL = 1, CPHA = 0, Clock idle low, data is clocked in on falling edge,
output data (change) on rising edge */
MRAA_SPI_MODE3 = 3, /**< CPOL = 1, CPHA = 1, Clock idle low, data is clocked in on rising, edge
output data (change) on falling edge */
} mraa_spi_mode_t;
/**
* Opaque pointer definition to the internal struct _spi
*/
typedef struct _spi* mraa_spi_context;
/**
* Initialise SPI_context, uses board mapping. Sets the muxes
*
* @param bus Bus to use, as listed in platform definition, normally 0
* @return Spi context or NULL
*/
mraa_spi_context mraa_spi_init(int bus);
/**
* Initialise SPI_context without any board configuration, selects a bus and a mux.
*
* @param bus Bus to use as listed by spidev
* @param cs Chip select to use as listed in spidev
* @return Spi context or NULL
*/
mraa_spi_context mraa_spi_init_raw(unsigned int bus, unsigned int cs);
/**
* Set the SPI device mode. see spidev 0-3.
*
* @param dev The Spi context
* @param mode The SPI mode, See Linux spidev
* @return Result of operation
*/
mraa_result_t mraa_spi_mode(mraa_spi_context dev, mraa_spi_mode_t mode);
/**
* Set the SPI device operating clock frequency.
*
* @param dev the Spi context
* @param hz the frequency in hz
* @return Result of operation
*/
mraa_result_t mraa_spi_frequency(mraa_spi_context dev, int hz);
/**
* Write Single Byte to the SPI device.
*
* @param dev The Spi context
* @param data Data to send
* @return Data received on the miso line or -1 in case of error
*/
int mraa_spi_write(mraa_spi_context dev, uint8_t data);
/**
* Write Two Bytes to the SPI device.
*
* @param dev The Spi context
* @param data Data to send
* @return Data received on the miso line
*/
int mraa_spi_write_word(mraa_spi_context dev, uint16_t data);
/**
* Write Buffer of bytes to the SPI device. The pointer return has to be
* free'd by the caller. It will return a NULL pointer in cases of error.
*
* @param dev The Spi context
* @param data to send
* @param length elements within buffer, Max 4096
* @return Data received on the miso line, same length as passed in
*/
uint8_t* mraa_spi_write_buf(mraa_spi_context dev, uint8_t* data, int length);
/**
* Write Buffer of uint16 to the SPI device. The pointer return has to be
* free'd by the caller. It will return a NULL pointer in cases of error.
*
* @param dev The Spi context
* @param data to send
* @param length elements (in bytes) within buffer, Max 4096
* @return Data received on the miso line, same length as passed in
*/
uint16_t* mraa_spi_write_buf_word(mraa_spi_context dev, uint16_t* data, int length);
/**
* Transfer Buffer of bytes to the SPI device. Both send and recv buffers
* are passed in
*
* @param dev The Spi context
* @param data to send
* @param rxbuf buffer to recv data back, may be NULL
* @param length elements within buffer, Max 4096
* @return Result of operation
*/
mraa_result_t mraa_spi_transfer_buf(mraa_spi_context dev, uint8_t* data, uint8_t* rxbuf, int length);
/**
* Transfer Buffer of uint16 to the SPI device. Both send and recv buffers
* are passed in
*
* @param dev The Spi context
* @param data to send
* @param rxbuf buffer to recv data back, may be NULL
* @param length elements (in bytes) within buffer, Max 4096
* @return Result of operation
*/
mraa_result_t mraa_spi_transfer_buf_word(mraa_spi_context dev, uint16_t* data, uint16_t* rxbuf, int length);
/**
* Change the SPI lsb mode
*
* @param dev The Spi context
* @param lsb Use least significant bit transmission. 0 for msbi
* @return Result of operation
*/
mraa_result_t mraa_spi_lsbmode(mraa_spi_context dev, mraa_boolean_t lsb);
/**
* Set bits per mode on transaction, defaults at 8
*
* @param dev The Spi context
* @param bits bits per word
* @return Result of operation
*/
mraa_result_t mraa_spi_bit_per_word(mraa_spi_context dev, unsigned int bits);
/**
* De-inits an mraa_spi_context device
*
* @param dev The Spi context
* @return Result of operation
*/
mraa_result_t mraa_spi_stop(mraa_spi_context dev);
#ifdef __cplusplus
}
#endif
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