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//
// Copyright 2017 Ettus Research, National Instruments Company
//
// SPDX-License-Identifier: GPL-3.0
//
#include "spidev.h"
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <sys/ioctl.h>
#include <linux/types.h>
#include <linux/spi/spidev.h>
#include <stdio.h>
int init_spi(int *fd, const char *device,
const uint32_t mode,
const uint32_t speed_hz,
const uint8_t bits_per_word,
const uint16_t delay_us
) {
if (!fd)
{
fprintf(stderr, "%s: was passed a null pointer\n",
__func__);
return -EINVAL;
}
*fd = open(device, O_RDWR);
if (*fd < 0) {
fprintf(stderr, "%s: Failed to open device. %s\n",
__func__, strerror(*fd));
return *fd;
}
// SPI_IOC_WR commands interpret our pointer as non-const, so play it safe
uint32_t set_mode = mode;
if (ioctl(*fd, SPI_IOC_WR_MODE32, &set_mode) < 0)
{
int err = errno;
fprintf(stderr, "%s: Failed to set mode. %s\n",
__func__, strerror(err));
return err;
}
uint32_t coerced_mode;
if (ioctl(*fd, SPI_IOC_RD_MODE32, &coerced_mode) < 0)
{
int err = errno;
fprintf(stderr, "%s: Failed to get mode. %s\n",
__func__, strerror(err));
return err;
}
if (coerced_mode != mode) {
fprintf(stderr, "%s: Failed to set mode to %d, got %d\n",
__func__, mode, coerced_mode);
return -ENOTSUP;
}
uint8_t set_bits_per_word = bits_per_word;
if (ioctl(*fd, SPI_IOC_WR_BITS_PER_WORD, &set_bits_per_word) < 0)
{
int err = errno;
fprintf(stderr, "%s: Failed to set bits per word. %s\n",
__func__, strerror(err));
return err;
}
uint8_t coerced_bits_per_word;
if (ioctl(*fd, SPI_IOC_RD_BITS_PER_WORD, &coerced_bits_per_word) < 0)
{
int err = errno;
fprintf(stderr, "%s: Failed to get bits per word (%s)\n",
__func__, strerror(err));
return err;
}
if (coerced_bits_per_word != bits_per_word) {
fprintf(stderr, "%s: Failed to set bits per word to %d, got %d\n",
__func__, bits_per_word, coerced_bits_per_word);
return -ENOTSUP;
}
uint32_t set_speed_hz = speed_hz;
if (ioctl(*fd, SPI_IOC_WR_MAX_SPEED_HZ, &set_speed_hz) < 0)
{
int err = errno;
fprintf(stderr, "%s: Failed to set speed (%s)\n",
__func__, strerror(err));
return err;
}
uint32_t coerced_speed_hz;
if (ioctl(*fd, SPI_IOC_RD_MAX_SPEED_HZ, &coerced_speed_hz) < 0)
{
int err = errno;
fprintf(stderr, "%s: Failed to get speed (%s)\n",
__func__, strerror(err));
return err;
}
if (coerced_speed_hz != speed_hz) {
fprintf(stderr, "%s: Failed to set speed to %d, got %d\n",
__func__, speed_hz, coerced_speed_hz);
return -ENOTSUP;
}
return 0;
}
int transfer(
int fd,
uint8_t *tx, uint8_t *rx, uint32_t len,
uint32_t speed_hz, uint8_t bits_per_word, uint16_t delay_us
) {
int err;
struct spi_ioc_transfer tr = {
.tx_buf = (unsigned long) tx,
.rx_buf = (unsigned long) rx,
.len = len,
.speed_hz = speed_hz,
.delay_usecs = delay_us,
.bits_per_word = bits_per_word,
.cs_change = 0,
.tx_nbits = 1, // Standard SPI
.rx_nbits = 1 // Standard SPI
};
err = ioctl(fd, SPI_IOC_MESSAGE(1), &tr);
if (err < 0) {
fprintf(stderr, "%s: Failed ioctl: %d\n", __func__, err);
perror("ioctl: \n");
return err;
}
return 0;
}
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