mirror of
https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git
synced 2026-10-24 00:48:53 +03:00
b77080c1d6
A collection of minor cleanups to make the examples more consistent and ease the addition of more examples: - reformat Makefile.am to simplify adding more examples - add line offset to value output - remove commas from edge event output - replace while(1) with for (;;) - fix a typo in Makefile.am - fix an error handling goto in toggle_line_value.c Signed-off-by: Kent Gibson <warthog618@gmail.com> Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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// SPDX-FileCopyrightText: 2023 Kent Gibson <warthog618@gmail.com>
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/* Minimal example of toggling a single line. */
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#include <errno.h>
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#include <gpiod.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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static struct gpiod_line_request *
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request_output_line(const char *chip_path, unsigned int offset,
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enum gpiod_line_value value, const char *consumer)
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{
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struct gpiod_request_config *req_cfg = NULL;
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struct gpiod_line_request *request = NULL;
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struct gpiod_line_settings *settings;
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struct gpiod_line_config *line_cfg;
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struct gpiod_chip *chip;
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int ret;
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chip = gpiod_chip_open(chip_path);
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if (!chip)
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return NULL;
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settings = gpiod_line_settings_new();
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if (!settings)
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goto close_chip;
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gpiod_line_settings_set_direction(settings,
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GPIOD_LINE_DIRECTION_OUTPUT);
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gpiod_line_settings_set_output_value(settings, value);
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line_cfg = gpiod_line_config_new();
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if (!line_cfg)
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goto free_settings;
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ret = gpiod_line_config_add_line_settings(line_cfg, &offset, 1,
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settings);
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if (ret)
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goto free_line_config;
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if (consumer) {
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req_cfg = gpiod_request_config_new();
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if (!req_cfg)
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goto free_line_config;
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gpiod_request_config_set_consumer(req_cfg, consumer);
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}
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request = gpiod_chip_request_lines(chip, req_cfg, line_cfg);
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gpiod_request_config_free(req_cfg);
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free_line_config:
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gpiod_line_config_free(line_cfg);
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free_settings:
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gpiod_line_settings_free(settings);
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close_chip:
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gpiod_chip_close(chip);
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return request;
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}
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static enum gpiod_line_value toggle_line_value(enum gpiod_line_value value)
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{
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return (value == GPIOD_LINE_VALUE_ACTIVE) ? GPIOD_LINE_VALUE_INACTIVE :
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GPIOD_LINE_VALUE_ACTIVE;
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}
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static const char * value_str(enum gpiod_line_value value)
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{
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if (value == GPIOD_LINE_VALUE_ACTIVE)
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return "Active";
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else if (value == GPIOD_LINE_VALUE_INACTIVE) {
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return "Inactive";
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} else {
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return "Unknown";
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}
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}
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int main(void)
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{
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/* Example configuration - customize to suit your situation. */
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static const char *const chip_path = "/dev/gpiochip0";
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static const unsigned int line_offset = 5;
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enum gpiod_line_value value = GPIOD_LINE_VALUE_ACTIVE;
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struct gpiod_line_request *request;
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request = request_output_line(chip_path, line_offset, value,
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"toggle-line-value");
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if (!request) {
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fprintf(stderr, "failed to request line: %s\n",
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strerror(errno));
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return EXIT_FAILURE;
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}
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for (;;) {
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printf("%d=%s\n", line_offset, value_str(value));
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sleep(1);
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value = toggle_line_value(value);
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gpiod_line_request_set_value(request, line_offset, value);
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}
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gpiod_line_request_release(request);
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return EXIT_SUCCESS;
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}
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