aboutsummaryrefslogtreecommitdiff
path: root/Documentation/spi/spidev_fdx.c
blob: 0ea3e51292fcbbbdb5010084f1e0c041d1048c8b (plain)
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
154
155
156
157
158
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>

#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <linux/types.h>
#include <linux/spi/spidev.h>


static int verbose;

static void do_read(int fd, int len)
{
	unsigned char	buf[32], *bp;
	int		status;

	/* read at least 2 bytes, no more than 32 */
	if (len < 2)
		len = 2;
	else if (len > sizeof(buf))
		len = sizeof(buf);
	memset(buf, 0, sizeof buf);

	status = read(fd, buf, len);
	if (status < 0) {
		perror("read");
		return;
	}
	if (status != len) {
		fprintf(stderr, "short read\n");
		return;
	}

	printf("read(%2d, %2d): %02x %02x,", len, status,
		buf[0], buf[1]);
	status -= 2;
	bp = buf + 2;
	while (status-- > 0)
		printf(" %02x", *bp++);
	printf("\n");
}

static void do_msg(int fd, int len)
{
	struct spi_ioc_transfer	xfer[2];
	unsigned char		buf[32], *bp;
	int			status;

	memset(xfer, 0, sizeof xfer);
	memset(buf, 0, sizeof buf);

	if (len > sizeof buf)
		len = sizeof buf;

	buf[0] = 0xaa;
	xfer[0].tx_buf = (unsigned long)buf;
	xfer[0].len = 1;

	xfer[1].rx_buf = (unsigned long) buf;
	xfer[1].len = len;

	status = ioctl(fd, SPI_IOC_MESSAGE(2), xfer);
	if (status < 0) {
		perror("SPI_IOC_MESSAGE");
		return;
	}

	printf("response(%2d, %2d): ", len, status);
	for (bp = buf; len; len--)
		printf(" %02x", *bp++);
	printf("\n");
}

static void dumpstat(const char *name, int fd)
{
	__u8	lsb, bits;
	__u32	mode, speed;

	if (ioctl(fd, SPI_IOC_RD_MODE32, &mode) < 0) {
		perror("SPI rd_mode");
		return;
	}
	if (ioctl(fd, SPI_IOC_RD_LSB_FIRST, &lsb) < 0) {
		perror("SPI rd_lsb_fist");
		return;
	}
	if (ioctl(fd, SPI_IOC_RD_BITS_PER_WORD, &bits) < 0) {
		perror("SPI bits_per_word");
		return;
	}
	if (ioctl(fd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) < 0) {
		perror("SPI max_speed_hz");
		return;
	}

	printf("%s: spi mode 0x%x, %d bits %sper word, %d Hz max\n",
		name, mode, bits, lsb ? "(lsb first) " : "", speed);
}

int main(int argc, char **argv)
{
	int		c;
	int		readcount = 0;
	int		msglen = 0;
	int		fd;
	const char	*name;

	while ((c = getopt(argc, argv, "hm:r:v")) != EOF) {
		switch (c) {
		case 'm':
			msglen = atoi(optarg);
			if (msglen < 0)
				goto usage;
			continue;
		case 'r':
			readcount = atoi(optarg);
			if (readcount < 0)
				goto usage;
			continue;
		case 'v':
			verbose++;
			continue;
		case 'h':
		case '?':
usage:
			fprintf(stderr,
				"usage: %s [-h] [-m N] [-r N] /dev/spidevB.D\n",
				argv[0]);
			return 1;
		}
	}

	if ((optind + 1) != argc)
		goto usage;
	name = argv[optind];

	fd = open(name, O_RDWR);
	if (fd < 0) {
		perror("open");
		return 1;
	}

	dumpstat(name, fd);

	if (msglen)
		do_msg(fd, msglen);

	if (readcount)
		do_read(fd, readcount);

	close(fd);
	return 0;
}