src/gpio_ctl.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 // SPDX-FileCopyrightText: 2023 Kent Gibson <[email protected]>
   3
   4 #include "common.h"
   5 #include <gpiod.h>
   6 #include "gpio_ctl.h"
   7
   8 struct gpiod_line_request *request_input_line(const char *chip_path,
   9                                                      unsigned int offset,
  10                                                      const char *consumer,
  11                                                      struct gpiod_line_settings *settings) {
  12         struct gpiod_line_request *request = NULL;
  13         struct gpiod_request_config *req_cfg = NULL;
  14         struct gpiod_line_config *line_cfg;
  15         struct gpiod_chip *chip;
  16         int ret;
  17
  18         if (!settings)
  19                 settings = gpiod_line_settings_new();
  20
  21         chip = gpiod_chip_open(chip_path);
  22         if (!chip)
  23                 goto free_settings;
  24
  25         line_cfg = gpiod_line_config_new();
  26         if (!line_cfg)
  27                 goto close_chip;
  28
  29         ret = gpiod_line_config_add_line_settings(line_cfg, &offset, 1,
  30                                                   settings);
  31         if (ret)
  32                 goto free_line_config;
  33
  34         if (consumer) {
  35                 req_cfg = gpiod_request_config_new();
  36                 if (!req_cfg)
  37                         goto free_line_config;
  38
  39                 gpiod_request_config_set_consumer(req_cfg, consumer);
  40         }
  41
  42         request = gpiod_chip_request_lines(chip, req_cfg, line_cfg);
  43
  44         gpiod_request_config_free(req_cfg);
  45
  46 free_line_config:
  47         gpiod_line_config_free(line_cfg);
  48
  49 close_chip:
  50         gpiod_chip_close(chip);
  51
  52 free_settings:
  53         gpiod_line_settings_free(settings);
  54         settings = NULL;
  55         return request;
  56 }
  57
  58 struct gpiod_edge_event * read_event(struct gpiod_line_request *request,
  59                                      struct gpiod_edge_event_buffer *event_buffer) {
  60         int err;
  61
  62         err = gpiod_line_request_read_edge_events(request, event_buffer, 1);
  63         if (err == -1) {
  64                 fprintf(stderr, "error reading edge events: %s\n",
  65                         strerror(errno));
  66                 return NULL;
  67         }
  68         return gpiod_edge_event_buffer_get_event(event_buffer, 0);
  69 }