1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
|
//
// 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 "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
) {
int err;
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\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\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\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;
}
|
