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1 | /* | |
2 | * This file is part of the libsigrok project. | |
3 | * | |
4 | * Copyright (C) 2015 Bartosz Golaszewski <bgolaszewski@baylibre.com> | |
5 | * | |
6 | * This program is free software: you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation, either version 3 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include <config.h> | |
21 | #include <glib.h> | |
22 | #include <glib/gstdio.h> | |
23 | #include <unistd.h> | |
24 | #include <fcntl.h> | |
25 | #include <errno.h> | |
26 | #include <string.h> | |
27 | #include <libsigrok/libsigrok.h> | |
28 | #include "libsigrok-internal.h" | |
29 | #include "gpio.h" | |
30 | ||
31 | #define LOG_PREFIX "gpio" | |
32 | ||
33 | static int open_and_write(const gchar *path, const gchar *buf) | |
34 | { | |
35 | FILE *fd; | |
36 | ssize_t wr; | |
37 | ||
38 | fd = g_fopen(path, "w"); | |
39 | if (!fd) { | |
40 | sr_err("Error opening %s: %s", path, g_strerror(errno)); | |
41 | return -1; | |
42 | } | |
43 | ||
44 | wr = g_fprintf(fd, "%s", buf); | |
45 | fclose(fd); | |
46 | if (wr < 0) { | |
47 | sr_err("Error writing to %s: %s", path, g_strerror(errno)); | |
48 | return -1; | |
49 | } | |
50 | ||
51 | return 0; | |
52 | } | |
53 | ||
54 | SR_PRIV int sr_gpio_export(unsigned gpio) | |
55 | { | |
56 | GString *path, *buf; | |
57 | gboolean exported; | |
58 | int status; | |
59 | ||
60 | path = g_string_sized_new(128); | |
61 | g_string_printf(path, "/sys/class/gpio/gpio%d", gpio); | |
62 | exported = g_file_test(path->str, G_FILE_TEST_IS_DIR); | |
63 | g_string_free(path, TRUE); | |
64 | if (exported) | |
65 | return 0; /* Already exported. */ | |
66 | ||
67 | status = sr_gpio_set_direction(gpio, GPIO_DIR_OUT); | |
68 | if (status < 0) | |
69 | return status; | |
70 | ||
71 | buf = g_string_sized_new(16); | |
72 | g_string_printf(buf, "%u\n", gpio); | |
73 | status = open_and_write("/sys/class/gpio/export", buf->str); | |
74 | g_string_free(buf, TRUE); | |
75 | ||
76 | return status; | |
77 | } | |
78 | ||
79 | SR_PRIV int sr_gpio_set_direction(unsigned gpio, unsigned direction) | |
80 | { | |
81 | GString *path, *buf; | |
82 | int status; | |
83 | ||
84 | path = g_string_sized_new(128); | |
85 | buf = g_string_sized_new(16); | |
86 | g_string_printf(path, "/sys/class/gpio/gpio%d/direction", gpio); | |
87 | g_string_printf(buf, "%s\n", direction == GPIO_DIR_IN ? "in" : "out"); | |
88 | ||
89 | status = open_and_write(path->str, buf->str); | |
90 | ||
91 | g_string_free(path, TRUE); | |
92 | g_string_free(buf, TRUE); | |
93 | ||
94 | return status; | |
95 | } | |
96 | ||
97 | SR_PRIV int sr_gpio_set_value(unsigned gpio, unsigned value) | |
98 | { | |
99 | GString *path, *buf; | |
100 | int status; | |
101 | ||
102 | path = g_string_sized_new(128); | |
103 | buf = g_string_sized_new(16); | |
104 | g_string_printf(path, "/sys/class/gpio/gpio%d/value", gpio); | |
105 | g_string_printf(buf, "%d\n", value); | |
106 | ||
107 | status = open_and_write(path->str, buf->str); | |
108 | ||
109 | g_string_free(path, TRUE); | |
110 | g_string_free(buf, TRUE); | |
111 | ||
112 | return status; | |
113 | } | |
114 | ||
115 | SR_PRIV int sr_gpio_get_value(int gpio) | |
116 | { | |
117 | FILE *fd; | |
118 | GString *path; | |
119 | int ret, status; | |
120 | ||
121 | path = g_string_sized_new(128); | |
122 | g_string_printf(path, "/sys/class/gpio/gpio%d/value", gpio); | |
123 | fd = g_fopen(path->str, "r"); | |
124 | if (!fd) { | |
125 | sr_err("Error opening %s: %s", path->str, g_strerror(errno)); | |
126 | g_string_free(path, TRUE); | |
127 | return -1; | |
128 | } | |
129 | ||
130 | status = fscanf(fd, "%d", &ret); | |
131 | fclose(fd); | |
132 | if (status != 1) { | |
133 | sr_err("Error reading from %s: %s", path->str, g_strerror(errno)); | |
134 | g_string_free(path, TRUE); | |
135 | return -1; | |
136 | } | |
137 | ||
138 | g_string_free(path, TRUE); | |
139 | return ret; | |
140 | } | |
141 | ||
142 | SR_PRIV int sr_gpio_setval_export(int gpio, int value) | |
143 | { | |
144 | int status; | |
145 | ||
146 | status = sr_gpio_export(gpio); | |
147 | if (status < 0) | |
148 | return status; | |
149 | ||
150 | status = sr_gpio_set_value(gpio, value); | |
151 | if (status < 0) | |
152 | return status; | |
153 | ||
154 | return 0; | |
155 | } | |
156 | ||
157 | SR_PRIV int sr_gpio_getval_export(int gpio) | |
158 | { | |
159 | int status; | |
160 | ||
161 | status = sr_gpio_export(gpio); | |
162 | if (status < 0) | |
163 | return status; | |
164 | ||
165 | return sr_gpio_get_value(gpio); | |
166 | } |