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
|
// SPDX-License-Identifier: GPL-2.0-or-later
// SPDX-FileCopyrightText: 2023 Kent Gibson <warthog618@gmail.com>
/* Minimal example of reading multiple lines. */
#include <errno.h>
#include <gpiod.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define NUM_LINES 3
/* Request a line as input. */
static struct gpiod_line_request *
request_input_lines(const char *chip_path, const unsigned int *offsets,
unsigned int num_lines, const char *consumer)
{
struct gpiod_request_config *req_cfg = NULL;
struct gpiod_line_request *request = NULL;
struct gpiod_line_settings *settings;
struct gpiod_line_config *line_cfg;
struct gpiod_chip *chip;
unsigned int i;
int ret;
chip = gpiod_chip_open(chip_path);
if (!chip)
return NULL;
settings = gpiod_line_settings_new();
if (!settings)
goto close_chip;
gpiod_line_settings_set_direction(settings, GPIOD_LINE_DIRECTION_INPUT);
line_cfg = gpiod_line_config_new();
if (!line_cfg)
goto free_settings;
for (i = 0; i < num_lines; i++) {
ret = gpiod_line_config_add_line_settings(line_cfg, &offsets[i],
1, settings);
if (ret)
goto free_line_config;
}
if (consumer) {
req_cfg = gpiod_request_config_new();
if (!req_cfg)
goto free_line_config;
gpiod_request_config_set_consumer(req_cfg, consumer);
}
request = gpiod_chip_request_lines(chip, req_cfg, line_cfg);
gpiod_request_config_free(req_cfg);
free_line_config:
gpiod_line_config_free(line_cfg);
free_settings:
gpiod_line_settings_free(settings);
close_chip:
gpiod_chip_close(chip);
return request;
}
static int print_values(const unsigned int *offsets, unsigned int num_lines,
enum gpiod_line_value *values)
{
unsigned int i;
for (i = 0; i < num_lines; i++) {
if (values[i] == GPIOD_LINE_VALUE_ACTIVE)
printf("%d=Active ", offsets[i]);
else if (values[i] == GPIOD_LINE_VALUE_INACTIVE) {
printf("%d=Inactive ", offsets[i]);
} else {
fprintf(stderr, "error reading value: %s\n",
strerror(errno));
return EXIT_FAILURE;
}
}
printf("\n");
return EXIT_SUCCESS;
}
int main(void)
{
/* Example configuration - customize to suit your situation. */
static const char *const chip_path = "/dev/gpiochip0";
static const unsigned int line_offsets[NUM_LINES] = { 5, 3, 7 };
enum gpiod_line_value values[NUM_LINES];
struct gpiod_line_request *request;
int ret;
request = request_input_lines(chip_path, line_offsets, NUM_LINES,
"get-multiple-line-values");
if (!request) {
fprintf(stderr, "failed to request lines: %s\n",
strerror(errno));
return EXIT_FAILURE;
}
ret = gpiod_line_request_get_values(request, values);
if (ret == -1) {
fprintf(stderr, "failed to get values: %s\n", strerror(errno));
return EXIT_FAILURE;
}
return print_values(line_offsets, NUM_LINES, values);
}
|
