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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 "libsigrok.h" | |
21 | #include "libsigrok-internal.h" | |
22 | #include "gpio.h" | |
23 | #include <glib.h> | |
24 | #include <glib/gstdio.h> | |
25 | #include <unistd.h> | |
26 | #include <fcntl.h> | |
27 | #include <errno.h> | |
28 | #include <string.h> | |
29 | ||
30 | #define LOG_PREFIX "gpio" | |
31 | ||
32 | static int open_and_write(const gchar *path, const gchar *buf) | |
33 | { | |
34 | FILE *fd; | |
35 | ssize_t wr; | |
36 | ||
37 | fd = g_fopen(path, "w"); | |
38 | if (!fd) { | |
391e23a9 | 39 | sr_err("Error opening %s: %s", path, strerror(errno)); |
289eebd7 BG |
40 | return -1; |
41 | } | |
42 | ||
43 | wr = g_fprintf(fd, "%s", buf); | |
44 | fclose(fd); | |
45 | if (wr < 0) { | |
391e23a9 | 46 | sr_err("Error writing to %s: %s", path, strerror(errno)); |
289eebd7 BG |
47 | return -1; |
48 | } | |
49 | ||
50 | return 0; | |
51 | } | |
52 | ||
53 | SR_PRIV int sr_gpio_export(unsigned gpio) | |
54 | { | |
55 | GString *path, *buf; | |
56 | gboolean exported; | |
57 | int status; | |
58 | ||
59 | path = g_string_sized_new(128); | |
60 | g_string_printf(path, "/sys/class/gpio/gpio%d", gpio); | |
61 | exported = g_file_test(path->str, G_FILE_TEST_IS_DIR); | |
62 | g_string_free(path, TRUE); | |
63 | if (exported) | |
64 | return 0; /* Already exported. */ | |
65 | ||
66 | buf = g_string_sized_new(16); | |
67 | g_string_printf(buf, "%u\n", gpio); | |
68 | status = open_and_write("/sys/class/gpio/export", buf->str); | |
69 | g_string_free(buf, TRUE); | |
70 | ||
71 | return status; | |
72 | } | |
73 | ||
74 | SR_PRIV int sr_gpio_set_direction(unsigned gpio, unsigned direction) | |
75 | { | |
76 | GString *path, *buf; | |
77 | int status; | |
78 | ||
79 | path = g_string_sized_new(128); | |
80 | buf = g_string_sized_new(16); | |
81 | g_string_printf(path, "/sys/class/gpio/gpio%d/direction", gpio); | |
82 | g_string_printf(buf, "%s\n", direction == GPIO_DIR_IN ? "in" : "out"); | |
83 | ||
84 | status = open_and_write(path->str, buf->str); | |
85 | ||
86 | g_string_free(path, TRUE); | |
87 | g_string_free(buf, TRUE); | |
88 | ||
89 | return status; | |
90 | } | |
91 | ||
92 | SR_PRIV int sr_gpio_set_value(unsigned gpio, unsigned value) | |
93 | { | |
94 | GString *path, *buf; | |
95 | int status; | |
96 | ||
97 | path = g_string_sized_new(128); | |
98 | buf = g_string_sized_new(16); | |
99 | g_string_printf(path, "/sys/class/gpio/gpio%d/value", gpio); | |
100 | g_string_printf(buf, "%d\n", value); | |
101 | ||
102 | status = open_and_write(path->str, buf->str); | |
103 | ||
104 | g_string_free(path, TRUE); | |
105 | g_string_free(buf, TRUE); | |
106 | ||
107 | return status; | |
108 | } | |
109 | ||
110 | SR_PRIV int sr_gpio_get_value(int gpio) | |
111 | { | |
112 | FILE *fd; | |
113 | GString *path; | |
114 | int ret, status; | |
115 | ||
116 | path = g_string_sized_new(128); | |
117 | g_string_printf(path, "/sys/class/gpio/gpio%d/value", gpio); | |
118 | fd = g_fopen(path->str, "r"); | |
119 | if (!fd) { | |
391e23a9 | 120 | sr_err("Error opening %s: %s", path->str, strerror(errno)); |
289eebd7 BG |
121 | g_string_free(path, TRUE); |
122 | return -1; | |
123 | } | |
124 | ||
125 | status = fscanf(fd, "%d", &ret); | |
126 | fclose(fd); | |
127 | if (status != 1) { | |
391e23a9 | 128 | sr_err("Error reading from %s: %s", path, strerror(errno)); |
289eebd7 BG |
129 | g_string_free(path, TRUE); |
130 | return -1; | |
131 | } | |
132 | ||
133 | g_string_free(path, TRUE); | |
134 | return ret; | |
135 | } | |
136 | ||
137 | SR_PRIV int sr_gpio_setval_export(int gpio, int value) | |
138 | { | |
139 | int status; | |
140 | ||
141 | status = sr_gpio_export(gpio); | |
142 | if (status < 0) | |
143 | return status; | |
144 | ||
145 | status = sr_gpio_set_direction(gpio, GPIO_DIR_OUT); | |
146 | if (status < 0) | |
147 | return status; | |
148 | ||
149 | status = sr_gpio_set_value(gpio, value); | |
150 | if (status < 0) | |
151 | return status; | |
152 | ||
153 | return 0; | |
154 | } | |
155 | ||
156 | SR_PRIV int sr_gpio_getval_export(int gpio) | |
157 | { | |
158 | int status; | |
159 | ||
160 | status = sr_gpio_export(gpio); | |
161 | if (status < 0) | |
162 | return status; | |
163 | ||
164 | status = sr_gpio_set_direction(gpio, GPIO_DIR_IN); | |
165 | if (status < 0) | |
166 | return status; | |
167 | ||
168 | return sr_gpio_get_value(gpio); | |
169 | } |