/* * Author: Thomas Ingleby * 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.c Interesting */ #ifdef __cplusplus extern "C" { #endif #include #include #include #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