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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/spidev_iface.hpp"
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>
#include <boost/format.hpp>
using namespace mpm::spi;
/******************************************************************************
* Implementation
*****************************************************************************/
class spidev_iface_impl : public spidev_iface
{
public:
spidev_iface_impl(
const std::string &device
) {
int ret;
_fd = open(device.c_str(), O_RDWR);
if (_fd < 0) {
throw std::runtime_error(str(
boost::format("Could not open spidev device %s")
% device
));
}
ret = ioctl(_fd, SPI_IOC_WR_MODE32, &_mode);
if (ret == -1) {
throw std::runtime_error("Could not set spidev mode");
}
ret = ioctl(_fd, SPI_IOC_RD_MODE32, &_mode);
if (ret == -1) {
throw std::runtime_error("Could not get spidev mode");
}
ret = ioctl(_fd, SPI_IOC_WR_BITS_PER_WORD, &_bits);
if (ret == -1) {
throw std::runtime_error("Could not set spidev bits per word");
}
ret = ioctl(_fd, SPI_IOC_RD_BITS_PER_WORD, &_bits);
if (ret == -1) {
throw std::runtime_error("Could not get spidev bits per word");
}
ret = ioctl(_fd, SPI_IOC_WR_MAX_SPEED_HZ, &_speed);
if (ret == -1) {
throw std::runtime_error("Could not set spidev max speed");
}
ret = ioctl(_fd, SPI_IOC_RD_MAX_SPEED_HZ, &_speed);
if (ret == -1) {
throw std::runtime_error("Could not get spidev max speed");
}
}
~spidev_iface_impl()
{
close(_fd);
}
uint32_t transact_spi(
int /* which_slave */,
const uhd::spi_config_t & /* config */,
uint32_t data,
size_t num_bits,
bool readback
) {
int ret(0);
uint8_t *tx_data = reinterpret_cast<uint8_t *>(&data);
assert(num_bits == 24);
uint8_t tx[] = {tx_data[2], tx_data[1], tx_data[0]};
uint8_t rx[3]; // Buffer length must match tx buffer
struct spi_ioc_transfer tr;
tr.tx_buf = (unsigned long) &tx[0];
tr.rx_buf = (unsigned long) &rx[0];
tr.len = num_bits >> 3;
tr.bits_per_word = _bits;
tr.tx_nbits = 1; // Standard SPI
tr.rx_nbits = 1; // Standard SPI
tr.speed_hz = _speed;
tr.delay_usecs = _delay;
ret = ioctl(_fd, SPI_IOC_MESSAGE(1), &tr);
if (ret < 1)
throw std::runtime_error("Could not send spidev message");
return rx[2]; // Assumes that only a single byte is being read.
}
uint32_t read_spi(
int which_slave,
const uhd::spi_config_t &config,
uint32_t data,
size_t num_bits
) {
return transact_spi(
which_slave, config, data, num_bits, true
);
}
void write_spi(
int which_slave,
const uhd::spi_config_t &config,
uint32_t data,
size_t num_bits
) {
transact_spi(
which_slave, config, data, num_bits, false
);
}
private:
int _fd;
uint8_t _mode = SPI_CPHA | SPI_CPOL;
uint32_t _speed = 2000000;
uint8_t _bits = 8;
uint16_t _delay = 0;
};
/******************************************************************************
* Factory
*****************************************************************************/
spidev_iface::sptr spidev_iface::make(
const std::string &device
) {
return sptr(new spidev_iface_impl(device));
}
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