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1/*
2 * GPIO tools - helpers library for the GPIO tools
3 *
4 * Copyright (C) 2015 Linus Walleij
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 */
10
11#include "gpio-utils.h"
1/*
2 * GPIO tools - helpers library for the GPIO tools
3 *
4 * Copyright (C) 2015 Linus Walleij
5 * Copyright (C) 2016 Bamvor Jian Zhang
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published by
9 * the Free Software Foundation.
10 */
11
12#include <unistd.h>
13#include <stdlib.h>
14#include <stdio.h>
15#include <errno.h>
16#include <string.h>
17#include <fcntl.h>
18#include <getopt.h>
19#include <sys/ioctl.h>
20#include <linux/gpio.h>
21#include "gpio-utils.h"
22
23#define COMSUMER "gpio-utils"
24
25/**
26 * doc: Operation of gpio
27 *
28 * Provide the api of gpiochip for chardev interface. There are two
29 * types of api. The first one provide as same function as each
30 * ioctl, including request and release for lines of gpio, read/write
31 * the value of gpio. If the user want to do lots of read and write of
32 * lines of gpio, user should use this type of api.
33 *
34 * The second one provide the easy to use api for user. Each of the
35 * following api will request gpio lines, do the operation and then
36 * release these lines.
37 */
38/**
39 * gpiotools_request_linehandle() - request gpio lines in a gpiochip
40 * @device_name: The name of gpiochip without prefix "/dev/",
41 * such as "gpiochip0"
42 * @lines: An array desired lines, specified by offset
43 * index for the associated GPIO device.
44 * @nline: The number of lines to request.
45 * @flag: The new flag for requsted gpio. Reference
46 * "linux/gpio.h" for the meaning of flag.
47 * @data: Default value will be set to gpio when flag is
48 * GPIOHANDLE_REQUEST_OUTPUT.
49 * @consumer_label: The name of consumer, such as "sysfs",
50 * "powerkey". This is useful for other users to
51 * know who is using.
52 *
53 * Request gpio lines through the ioctl provided by chardev. User
54 * could call gpiotools_set_values() and gpiotools_get_values() to
55 * read and write respectively through the returned fd. Call
56 * gpiotools_release_linehandle() to release these lines after that.
57 *
58 * Return: On success return the fd;
59 * On failure return the errno.
60 */
61int gpiotools_request_linehandle(const char *device_name, unsigned int *lines,
62 unsigned int nlines, unsigned int flag,
63 struct gpiohandle_data *data,
64 const char *consumer_label)
65{
66 struct gpiohandle_request req;
67 char *chrdev_name;
68 int fd;
69 int i;
70 int ret;
71
72 ret = asprintf(&chrdev_name, "/dev/%s", device_name);
73 if (ret < 0)
74 return -ENOMEM;
75
76 fd = open(chrdev_name, 0);
77 if (fd == -1) {
78 ret = -errno;
79 fprintf(stderr, "Failed to open %s, %s\n",
80 chrdev_name, strerror(errno));
81 goto exit_close_error;
82 }
83
84 for (i = 0; i < nlines; i++)
85 req.lineoffsets[i] = lines[i];
86
87 req.flags = flag;
88 strcpy(req.consumer_label, consumer_label);
89 req.lines = nlines;
90 if (flag & GPIOHANDLE_REQUEST_OUTPUT)
91 memcpy(req.default_values, data, sizeof(req.default_values));
92
93 ret = ioctl(fd, GPIO_GET_LINEHANDLE_IOCTL, &req);
94 if (ret == -1) {
95 ret = -errno;
96 fprintf(stderr, "Failed to issue %s (%d), %s\n",
97 "GPIO_GET_LINEHANDLE_IOCTL", ret, strerror(errno));
98 }
99
100exit_close_error:
101 if (close(fd) == -1)
102 perror("Failed to close GPIO character device file");
103 free(chrdev_name);
104 return ret < 0 ? ret : req.fd;
105}
106/**
107 * gpiotools_set_values(): Set the value of gpio(s)
108 * @fd: The fd returned by
109 * gpiotools_request_linehandle().
110 * @data: The array of values want to set.
111 *
112 * Return: On success return 0;
113 * On failure return the errno.
114 */
115int gpiotools_set_values(const int fd, struct gpiohandle_data *data)
116{
117 int ret;
118
119 ret = ioctl(fd, GPIOHANDLE_SET_LINE_VALUES_IOCTL, data);
120 if (ret == -1) {
121 ret = -errno;
122 fprintf(stderr, "Failed to issue %s (%d), %s\n",
123 "GPIOHANDLE_SET_LINE_VALUES_IOCTL", ret,
124 strerror(errno));
125 }
126
127 return ret;
128}
129
130/**
131 * gpiotools_get_values(): Get the value of gpio(s)
132 * @fd: The fd returned by
133 * gpiotools_request_linehandle().
134 * @data: The array of values get from hardware.
135 *
136 * Return: On success return 0;
137 * On failure return the errno.
138 */
139int gpiotools_get_values(const int fd, struct gpiohandle_data *data)
140{
141 int ret;
142
143 ret = ioctl(fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, data);
144 if (ret == -1) {
145 ret = -errno;
146 fprintf(stderr, "Failed to issue %s (%d), %s\n",
147 "GPIOHANDLE_GET_LINE_VALUES_IOCTL", ret,
148 strerror(errno));
149 }
150
151 return ret;
152}
153
154/**
155 * gpiotools_release_linehandle(): Release the line(s) of gpiochip
156 * @fd: The fd returned by
157 * gpiotools_request_linehandle().
158 *
159 * Return: On success return 0;
160 * On failure return the errno.
161 */
162int gpiotools_release_linehandle(const int fd)
163{
164 int ret;
165
166 ret = close(fd);
167 if (ret == -1) {
168 perror("Failed to close GPIO LINEHANDLE device file");
169 ret = -errno;
170 }
171
172 return ret;
173}
174
175/**
176 * gpiotools_get(): Get value from specific line
177 * @device_name: The name of gpiochip without prefix "/dev/",
178 * such as "gpiochip0"
179 * @line: number of line, such as 2.
180 *
181 * Return: On success return 0;
182 * On failure return the errno.
183 */
184int gpiotools_get(const char *device_name, unsigned int line)
185{
186 struct gpiohandle_data data;
187 unsigned int lines[] = {line};
188
189 gpiotools_gets(device_name, lines, 1, &data);
190 return data.values[0];
191}
192
193
194/**
195 * gpiotools_gets(): Get values from specific lines.
196 * @device_name: The name of gpiochip without prefix "/dev/",
197 * such as "gpiochip0".
198 * @lines: An array desired lines, specified by offset
199 * index for the associated GPIO device.
200 * @nline: The number of lines to request.
201 * @data: The array of values get from gpiochip.
202 *
203 * Return: On success return 0;
204 * On failure return the errno.
205 */
206int gpiotools_gets(const char *device_name, unsigned int *lines,
207 unsigned int nlines, struct gpiohandle_data *data)
208{
209 int fd;
210 int ret;
211 int ret_close;
212
213 ret = gpiotools_request_linehandle(device_name, lines, nlines,
214 GPIOHANDLE_REQUEST_INPUT, data,
215 COMSUMER);
216 if (ret < 0)
217 return ret;
218
219 fd = ret;
220 ret = gpiotools_get_values(fd, data);
221 ret_close = gpiotools_release_linehandle(fd);
222 return ret < 0 ? ret : ret_close;
223}
224
225/**
226 * gpiotools_set(): Set value to specific line
227 * @device_name: The name of gpiochip without prefix "/dev/",
228 * such as "gpiochip0"
229 * @line: number of line, such as 2.
230 * @value: The value of gpio, must be 0(low) or 1(high).
231 *
232 * Return: On success return 0;
233 * On failure return the errno.
234 */
235int gpiotools_set(const char *device_name, unsigned int line,
236 unsigned int value)
237{
238 struct gpiohandle_data data;
239 unsigned int lines[] = {line};
240
241 data.values[0] = value;
242 return gpiotools_sets(device_name, lines, 1, &data);
243}
244
245/**
246 * gpiotools_sets(): Set values to specific lines.
247 * @device_name: The name of gpiochip without prefix "/dev/",
248 * such as "gpiochip0".
249 * @lines: An array desired lines, specified by offset
250 * index for the associated GPIO device.
251 * @nline: The number of lines to request.
252 * @data: The array of values set to gpiochip, must be
253 * 0(low) or 1(high).
254 *
255 * Return: On success return 0;
256 * On failure return the errno.
257 */
258int gpiotools_sets(const char *device_name, unsigned int *lines,
259 unsigned int nlines, struct gpiohandle_data *data)
260{
261 int ret;
262
263 ret = gpiotools_request_linehandle(device_name, lines, nlines,
264 GPIOHANDLE_REQUEST_OUTPUT, data,
265 COMSUMER);
266 if (ret < 0)
267 return ret;
268
269 return gpiotools_release_linehandle(ret);
270}