137 lines
4.3 KiB
C
137 lines
4.3 KiB
C
/*
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* Author: Thomas Ingleby <thomas.c.ingleby@intel.com>
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* Copyright (c) 2014 Intel Corporation.
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#pragma once
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/**
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* @file
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* @brief System Packet Interface
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*
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* This file defines the spi interface for libmraa. A Spi object in libmraa
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* represents a spidev device. Linux spidev devices are created per spi bus and
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* every chip select available on that bus has another spidev 'file'. A lot
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* more information on spidev devices is available
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* [here](https://www.kernel.org/doc/Documentation/spi/spidev).
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*
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* @snippet spi_mcp4261.c Interesting
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*/
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <stdio.h>
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#include <fcntl.h>
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#include <stdint.h>
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#include "common.h"
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/**
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* MRAA supported platform types
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*/
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typedef enum {
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MRAA_SPI_MODE0 = 0, /**< CPOL = 0, CPHA = 0, Clock idle low, data is clocked in on rising edge, output data (change) on falling edge */
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MRAA_SPI_MODE1 = 1, /**< CPOL = 0, CPHA = 1, Clock idle low, data is clocked in on falling edge, output data (change) on rising edge */
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MRAA_SPI_MODE2 = 2, /**< CPOL = 1, CPHA = 0, Clock idle low, data is clocked in on falling edge, output data (change) on rising edge */
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MRAA_SPI_MODE3 = 3, /**< CPOL = 1, CPHA = 1, Clock idle low, data is clocked in on rising, edge output data (change) on falling edge */
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} mraa_spi_mode_t;
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/**
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* Opaque pointer definition to the internal struct _spi
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*/
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typedef struct _spi* mraa_spi_context;
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/**
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* Initialise SPI_context, uses board mapping. Sets the muxes
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*
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* @param bus Bus to use, as listed in platform definition, normally 0
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* @return Spi context or NULL
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*/
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mraa_spi_context mraa_spi_init(int bus);
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/**
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* Set the SPI device mode. see spidev 0-3.
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*
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* @param dev The Spi context
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* @param mode The SPI mode, See Linux spidev
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* @return Spi context or NULL
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*/
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mraa_result_t mraa_spi_mode(mraa_spi_context dev, mraa_spi_mode_t mode);
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/** Set the SPI device operating clock frequency.
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*
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* @param dev the Spi context
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* @param hz the frequency in hz
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* @return mraa_spi_context The returned initialised SPI context
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*/
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mraa_result_t mraa_spi_frequency(mraa_spi_context dev, int hz);
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/** Write Single Byte to the SPI device.
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*
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* @param dev The Spi context
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* @param data Data to send
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* @return Data received on the miso line
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*/
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uint8_t mraa_spi_write(mraa_spi_context dev, uint8_t data);
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/** Write Buffer of bytes to the SPI device. The pointer return has to be
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* free'd by the caller.
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*
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* @param dev The Spi context
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* @param data to send
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* @param length elements within buffer, Max 4096
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* @return Data received on the miso line, same length as passed in
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*/
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uint8_t* mraa_spi_write_buf(mraa_spi_context dev, uint8_t* data, int length);
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/**
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* Change the SPI lsb mode
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*
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* @param dev The Spi context
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* @param lsb Use least significant bit transmission. 0 for msbi
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* @return Result of operation
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*/
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mraa_result_t mraa_spi_lsbmode(mraa_spi_context dev, mraa_boolean_t lsb);
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/**
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* Set bits per mode on transaction, defaults at 8
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*
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* @param dev The Spi context
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* @param bits bits per word
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* @return Result of operation
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*/
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mraa_result_t mraa_spi_bit_per_word(mraa_spi_context dev, unsigned int bits);
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/**
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* De-inits an mraa_spi_context device
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*
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* @param dev The Spi context
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* @return Result of operation
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*/
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mraa_result_t mraa_spi_stop(mraa_spi_context dev);
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#ifdef __cplusplus
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}
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#endif
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