summaryrefslogtreecommitdiff
path: root/tools/gpio/gpio-utils.c
blob: 06003789e7c7ed7e88f4c890e357eea822b97655 (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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
// SPDX-License-Identifier: GPL-2.0-only
/*
 * GPIO tools - helpers library for the GPIO tools
 *
 * Copyright (C) 2015 Linus Walleij
 * Copyright (C) 2016 Bamvor Jian Zhang
 */

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/ioctl.h>
#include <linux/gpio.h>
#include "gpio-utils.h"

#define CONSUMER "gpio-utils"

/**
 * doc: Operation of gpio
 *
 * Provide the api of gpiochip for chardev interface. There are two
 * types of api.  The first one provide as same function as each
 * ioctl, including request and release for lines of gpio, read/write
 * the value of gpio. If the user want to do lots of read and write of
 * lines of gpio, user should use this type of api.
 *
 * The second one provide the easy to use api for user. Each of the
 * following api will request gpio lines, do the operation and then
 * release these lines.
 */
/**
 * gpiotools_request_linehandle() - request gpio lines in a gpiochip
 * @device_name:	The name of gpiochip without prefix "/dev/",
 *			such as "gpiochip0"
 * @lines:		An array desired lines, specified by offset
 *			index for the associated GPIO device.
 * @nline:		The number of lines to request.
 * @flag:		The new flag for requsted gpio. Reference
 *			"linux/gpio.h" for the meaning of flag.
 * @data:		Default value will be set to gpio when flag is
 *			GPIOHANDLE_REQUEST_OUTPUT.
 * @consumer_label:	The name of consumer, such as "sysfs",
 *			"powerkey". This is useful for other users to
 *			know who is using.
 *
 * Request gpio lines through the ioctl provided by chardev. User
 * could call gpiotools_set_values() and gpiotools_get_values() to
 * read and write respectively through the returned fd. Call
 * gpiotools_release_linehandle() to release these lines after that.
 *
 * Return:		On success return the fd;
 *			On failure return the errno.
 */
int gpiotools_request_linehandle(const char *device_name, unsigned int *lines,
				 unsigned int nlines, unsigned int flag,
				 struct gpiohandle_data *data,
				 const char *consumer_label)
{
	struct gpiohandle_request req;
	char *chrdev_name;
	int fd;
	int i;
	int ret;

	ret = asprintf(&chrdev_name, "/dev/%s", device_name);
	if (ret < 0)
		return -ENOMEM;

	fd = open(chrdev_name, 0);
	if (fd == -1) {
		ret = -errno;
		fprintf(stderr, "Failed to open %s, %s\n",
			chrdev_name, strerror(errno));
		goto exit_close_error;
	}

	for (i = 0; i < nlines; i++)
		req.lineoffsets[i] = lines[i];

	req.flags = flag;
	strcpy(req.consumer_label, consumer_label);
	req.lines = nlines;
	if (flag & GPIOHANDLE_REQUEST_OUTPUT)
		memcpy(req.default_values, data, sizeof(req.default_values));

	ret = ioctl(fd, GPIO_GET_LINEHANDLE_IOCTL, &req);
	if (ret == -1) {
		ret = -errno;
		fprintf(stderr, "Failed to issue %s (%d), %s\n",
			"GPIO_GET_LINEHANDLE_IOCTL", ret, strerror(errno));
	}

exit_close_error:
	if (close(fd) == -1)
		perror("Failed to close GPIO character device file");
	free(chrdev_name);
	return ret < 0 ? ret : req.fd;
}
/**
 * gpiotools_set_values(): Set the value of gpio(s)
 * @fd:			The fd returned by
 *			gpiotools_request_linehandle().
 * @data:		The array of values want to set.
 *
 * Return:		On success return 0;
 *			On failure return the errno.
 */
int gpiotools_set_values(const int fd, struct gpiohandle_data *data)
{
	int ret;

	ret = ioctl(fd, GPIOHANDLE_SET_LINE_VALUES_IOCTL, data);
	if (ret == -1) {
		ret = -errno;
		fprintf(stderr, "Failed to issue %s (%d), %s\n",
			"GPIOHANDLE_SET_LINE_VALUES_IOCTL", ret,
			strerror(errno));
	}

	return ret;
}

/**
 * gpiotools_get_values(): Get the value of gpio(s)
 * @fd:			The fd returned by
 *			gpiotools_request_linehandle().
 * @data:		The array of values get from hardware.
 *
 * Return:		On success return 0;
 *			On failure return the errno.
 */
int gpiotools_get_values(const int fd, struct gpiohandle_data *data)
{
	int ret;

	ret = ioctl(fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, data);
	if (ret == -1) {
		ret = -errno;
		fprintf(stderr, "Failed to issue %s (%d), %s\n",
			"GPIOHANDLE_GET_LINE_VALUES_IOCTL", ret,
			strerror(errno));
	}

	return ret;
}

/**
 * gpiotools_release_linehandle(): Release the line(s) of gpiochip
 * @fd:			The fd returned by
 *			gpiotools_request_linehandle().
 *
 * Return:		On success return 0;
 *			On failure return the errno.
 */
int gpiotools_release_linehandle(const int fd)
{
	int ret;

	ret = close(fd);
	if (ret == -1) {
		perror("Failed to close GPIO LINEHANDLE device file");
		ret = -errno;
	}

	return ret;
}

/**
 * gpiotools_get(): Get value from specific line
 * @device_name:	The name of gpiochip without prefix "/dev/",
 *			such as "gpiochip0"
 * @line:		number of line, such as 2.
 *
 * Return:		On success return 0;
 *			On failure return the errno.
 */
int gpiotools_get(const char *device_name, unsigned int line)
{
	struct gpiohandle_data data;
	unsigned int lines[] = {line};

	gpiotools_gets(device_name, lines, 1, &data);
	return data.values[0];
}


/**
 * gpiotools_gets(): Get values from specific lines.
 * @device_name:	The name of gpiochip without prefix "/dev/",
 *			such as "gpiochip0".
 * @lines:		An array desired lines, specified by offset
 *			index for the associated GPIO device.
 * @nline:		The number of lines to request.
 * @data:		The array of values get from gpiochip.
 *
 * Return:		On success return 0;
 *			On failure return the errno.
 */
int gpiotools_gets(const char *device_name, unsigned int *lines,
		   unsigned int nlines, struct gpiohandle_data *data)
{
	int fd;
	int ret;
	int ret_close;

	ret = gpiotools_request_linehandle(device_name, lines, nlines,
					   GPIOHANDLE_REQUEST_INPUT, data,
					   CONSUMER);
	if (ret < 0)
		return ret;

	fd = ret;
	ret = gpiotools_get_values(fd, data);
	ret_close = gpiotools_release_linehandle(fd);
	return ret < 0 ? ret : ret_close;
}

/**
 * gpiotools_set(): Set value to specific line
 * @device_name:	The name of gpiochip without prefix "/dev/",
 *			such as "gpiochip0"
 * @line:		number of line, such as 2.
 * @value:		The value of gpio, must be 0(low) or 1(high).
 *
 * Return:		On success return 0;
 *			On failure return the errno.
 */
int gpiotools_set(const char *device_name, unsigned int line,
		  unsigned int value)
{
	struct gpiohandle_data data;
	unsigned int lines[] = {line};

	data.values[0] = value;
	return gpiotools_sets(device_name, lines, 1, &data);
}

/**
 * gpiotools_sets(): Set values to specific lines.
 * @device_name:	The name of gpiochip without prefix "/dev/",
 *			such as "gpiochip0".
 * @lines:		An array desired lines, specified by offset
 *			index for the associated GPIO device.
 * @nline:		The number of lines to request.
 * @data:		The array of values set to gpiochip, must be
 *			0(low) or 1(high).
 *
 * Return:		On success return 0;
 *			On failure return the errno.
 */
int gpiotools_sets(const char *device_name, unsigned int *lines,
		   unsigned int nlines, struct gpiohandle_data *data)
{
	int ret;

	ret = gpiotools_request_linehandle(device_name, lines, nlines,
					   GPIOHANDLE_REQUEST_OUTPUT, data,
					   CONSUMER);
	if (ret < 0)
		return ret;

	return gpiotools_release_linehandle(ret);
}