1 // SPDX-License-Identifier: GPL-2.0-only
3  * GPIO tools - helpers library for the GPIO tools
17 #include <linux/gpio.h>
18 #include "gpio-utils.h"
20 #define CONSUMER "gpio-utils"
23  * DOC: Operation of gpio
27  * ioctl, including request and release for lines of gpio, read/write
28  * the value of gpio. If the user want to do lots of read and write of
29  * lines of gpio, user should use this type of api.
32  * following api will request gpio lines, do the operation and then
33  * release these lines.
37  * gpiotools_request_line() - request gpio lines in a gpiochip
40  * @lines:		An array desired lines, specified by offset
41  *			index for the associated GPIO device.
42  * @num_lines:		The number of lines to request.
43  * @config:		The new config for requested gpio. Reference
44  *			"linux/gpio.h" for config details.
49  * Request gpio lines through the ioctl provided by chardev. User
52  * gpiotools_release_line() to release these lines after that.
57 int gpiotools_request_line(const char *device_name, unsigned int *lines,  in gpiotools_request_line()  argument
70 		return -ENOMEM;  in gpiotools_request_line()
73 	if (fd == -1) {  in gpiotools_request_line()
74 		ret = -errno;  in gpiotools_request_line()
82 		req.offsets[i] = lines[i];  in gpiotools_request_line()
89 	if (ret == -1) {  in gpiotools_request_line()
90 		ret = -errno;  in gpiotools_request_line()
95 	if (close(fd) == -1)  in gpiotools_request_line()
96 		perror("Failed to close GPIO character device file");  in gpiotools_request_line()
103  * gpiotools_set_values() - Set the value of gpio(s)
116 	if (ret == -1) {  in gpiotools_set_values()
117 		ret = -errno;  in gpiotools_set_values()
127  * gpiotools_get_values() - Get the value of gpio(s)
140 	if (ret == -1) {  in gpiotools_get_values()
141 		ret = -errno;  in gpiotools_get_values()
151  * gpiotools_release_line() - Release the line(s) of gpiochip
163 	if (ret == -1) {  in gpiotools_release_line()
164 		perror("Failed to close GPIO LINE device file");  in gpiotools_release_line()
165 		ret = -errno;  in gpiotools_release_line()
172  * gpiotools_get() - Get value from specific line
184 	unsigned int lines[] = {line};  in gpiotools_get()  local
186 	ret = gpiotools_gets(device_name, lines, 1, &value);  in gpiotools_get()
194  * gpiotools_gets() - Get values from specific lines.
197  * @lines:		An array desired lines, specified by offset
198  *			index for the associated GPIO device.
199  * @num_lines:		The number of lines to request.
205 int gpiotools_gets(const char *device_name, unsigned int *lines,  in gpiotools_gets()  argument
216 	ret = gpiotools_request_line(device_name, lines, num_lines,  in gpiotools_gets()
233  * gpiotools_set() - Set value to specific line
237  * @value:		The value of gpio, must be 0(low) or 1(high).
245 	unsigned int lines[] = {line};  in gpiotools_set()  local
247 	return gpiotools_sets(device_name, lines, 1, &value);  in gpiotools_set()
251  * gpiotools_sets() - Set values to specific lines.
254  * @lines:		An array desired lines, specified by offset
255  *			index for the associated GPIO device.
256  * @num_lines:		The number of lines to request.
263 int gpiotools_sets(const char *device_name, unsigned int *lines,  in gpiotools_sets()  argument
278 	ret = gpiotools_request_line(device_name, lines, num_lines,  in gpiotools_sets()