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//
// Copyright 2017 Ettus Research (National Instruments)
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
#include <mpm/spi/spi_iface.hpp>
#include <mpm/exception.hpp>
extern "C" {
#include "spidev.h"
}
#include <linux/spi/spidev.h>
#include <boost/format.hpp>
#include <iostream>
using namespace mpm::spi;
/******************************************************************************
* Implementation
*****************************************************************************/
class spidev_iface_impl : public spi_iface
{
public:
spidev_iface_impl(
const std::string &device,
const int max_speed_hz
) : _speed(max_speed_hz)
{
if (!init_spi(
&_fd,
device.c_str(),
_mode, _speed, _bits, _delay
)) {
throw mpm::runtime_error(str(
boost::format("Could not initialize spidev device %s")
% device
));
}
if (_fd < 0) {
throw mpm::runtime_error(str(
boost::format("Could not open spidev device %s")
% device
));
}
}
~spidev_iface_impl()
{
close(_fd);
}
uint32_t transfer24_8(
const uint32_t data_
) {
int ret(0);
uint32_t data = data_;
uint8_t *tx_data = reinterpret_cast<uint8_t *>(&data);
// Create tx and rx buffers:
uint8_t tx[] = {tx_data[2], tx_data[1], tx_data[0]}; // FIXME guarantee endianness
uint8_t rx[3]; // Buffer length must match tx buffer
if (transfer(
_fd,
&tx[0], &rx[0],
3,
_speed, _bits, _delay
) != 0) {
throw mpm::runtime_error(str(
boost::format("SPI Transaction failed!")
));
}
// Assumes that only a single byte is being read.
// TODO the function does not advertise this. Should probably fix.
return uint32_t(rx[2]);
}
private:
int _fd;
uint32_t _mode = SPI_CPHA | SPI_CPOL;
uint32_t _speed = 2000000;
uint8_t _bits = 8;
uint16_t _delay = 0;
};
/******************************************************************************
* Factory
*****************************************************************************/
spi_iface::sptr spi_iface::make_spidev(
const std::string &device,
const int speed_hz
) {
return std::make_shared<spidev_iface_impl>(
device, speed_hz
);
}
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