1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * GPIO mockup cdev test helper
  4 *
  5 * Copyright (C) 2020 Kent Gibson
  6 */
  7
  8#include <errno.h>
  9#include <fcntl.h>
 10#include <signal.h>
 11#include <stdint.h>
 12#include <stdio.h>
 13#include <stdlib.h>
 14#include <string.h>
 15#include <unistd.h>
 16#include <sys/ioctl.h>
 17#include <linux/gpio.h>
 18
 19#define CONSUMER	"gpio-mockup-cdev"
 20
 21static int request_line_v2(int cfd, unsigned int offset,
 22			   uint64_t flags, unsigned int val)
 23{
 24	struct gpio_v2_line_request req;
 25	int ret;
 26
 27	memset(&req, 0, sizeof(req));
 28	req.num_lines = 1;
 29	req.offsets[0] = offset;
 30	req.config.flags = flags;
 31	strcpy(req.consumer, CONSUMER);
 32	if (flags & GPIO_V2_LINE_FLAG_OUTPUT) {
 33		req.config.num_attrs = 1;
 34		req.config.attrs[0].mask = 1;
 35		req.config.attrs[0].attr.id = GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES;
 36		if (val)
 37			req.config.attrs[0].attr.values = 1;
 38	}
 39	ret = ioctl(cfd, GPIO_V2_GET_LINE_IOCTL, &req);
 40	if (ret == -1)
 41		return -errno;
 42	return req.fd;
 43}
 44
 45
 46static int get_value_v2(int lfd)
 47{
 48	struct gpio_v2_line_values vals;
 49	int ret;
 50
 51	memset(&vals, 0, sizeof(vals));
 52	vals.mask = 1;
 53	ret = ioctl(lfd, GPIO_V2_LINE_GET_VALUES_IOCTL, &vals);
 54	if (ret == -1)
 55		return -errno;
 56	return vals.bits & 0x1;
 57}
 58
 59static int request_line_v1(int cfd, unsigned int offset,
 60			   uint32_t flags, unsigned int val)
 61{
 62	struct gpiohandle_request req;
 63	int ret;
 64
 65	memset(&req, 0, sizeof(req));
 66	req.lines = 1;
 67	req.lineoffsets[0] = offset;
 68	req.flags = flags;
 69	strcpy(req.consumer_label, CONSUMER);
 70	if (flags & GPIOHANDLE_REQUEST_OUTPUT)
 71		req.default_values[0] = val;
 72
 73	ret = ioctl(cfd, GPIO_GET_LINEHANDLE_IOCTL, &req);
 74	if (ret == -1)
 75		return -errno;
 76	return req.fd;
 77}
 78
 79static int get_value_v1(int lfd)
 80{
 81	struct gpiohandle_data vals;
 82	int ret;
 83
 84	memset(&vals, 0, sizeof(vals));
 85	ret = ioctl(lfd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &vals);
 86	if (ret == -1)
 87		return -errno;
 88	return vals.values[0];
 89}
 90
 91static void usage(char *prog)
 92{
 93	printf("Usage: %s [-l] [-b <bias>] [-s <value>] [-u <uAPI>] <gpiochip> <offset>\n", prog);
 94	printf("        -b: set line bias to one of pull-down, pull-up, disabled\n");
 95	printf("               (default is to leave bias unchanged):\n");
 96	printf("        -l: set line active low (default is active high)\n");
 97	printf("        -s: set line value (default is to get line value)\n");
 98	printf("        -u: uAPI version to use (default is 2)\n");
 99	exit(-1);
100}
101
102static int wait_signal(void)
103{
104	int sig;
105	sigset_t wset;
106
107	sigemptyset(&wset);
108	sigaddset(&wset, SIGHUP);
109	sigaddset(&wset, SIGINT);
110	sigaddset(&wset, SIGTERM);
111	sigwait(&wset, &sig);
112
113	return sig;
114}
115
116int main(int argc, char *argv[])
117{
118	char *chip;
119	int opt, ret, cfd, lfd;
120	unsigned int offset, val = 0, abiv;
121	uint32_t flags_v1;
122	uint64_t flags_v2;
123
124	abiv = 2;
125	ret = 0;
126	flags_v1 = GPIOHANDLE_REQUEST_INPUT;
127	flags_v2 = GPIO_V2_LINE_FLAG_INPUT;
128
129	while ((opt = getopt(argc, argv, "lb:s:u:")) != -1) {
130		switch (opt) {
131		case 'l':
132			flags_v1 |= GPIOHANDLE_REQUEST_ACTIVE_LOW;
133			flags_v2 |= GPIO_V2_LINE_FLAG_ACTIVE_LOW;
134			break;
135		case 'b':
136			if (strcmp("pull-up", optarg) == 0) {
137				flags_v1 |= GPIOHANDLE_REQUEST_BIAS_PULL_UP;
138				flags_v2 |= GPIO_V2_LINE_FLAG_BIAS_PULL_UP;
139			} else if (strcmp("pull-down", optarg) == 0) {
140				flags_v1 |= GPIOHANDLE_REQUEST_BIAS_PULL_DOWN;
141				flags_v2 |= GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN;
142			} else if (strcmp("disabled", optarg) == 0) {
143				flags_v1 |= GPIOHANDLE_REQUEST_BIAS_DISABLE;
144				flags_v2 |= GPIO_V2_LINE_FLAG_BIAS_DISABLED;
145			}
146			break;
147		case 's':
148			val = atoi(optarg);
149			flags_v1 &= ~GPIOHANDLE_REQUEST_INPUT;
150			flags_v1 |= GPIOHANDLE_REQUEST_OUTPUT;
151			flags_v2 &= ~GPIO_V2_LINE_FLAG_INPUT;
152			flags_v2 |= GPIO_V2_LINE_FLAG_OUTPUT;
153			break;
154		case 'u':
155			abiv = atoi(optarg);
156			break;
157		default:
158			usage(argv[0]);
159		}
160	}
161
162	if (argc < optind + 2)
163		usage(argv[0]);
164
165	chip = argv[optind];
166	offset = atoi(argv[optind + 1]);
167
168	cfd = open(chip, 0);
169	if (cfd == -1) {
170		fprintf(stderr, "Failed to open %s: %s\n", chip, strerror(errno));
171		return -errno;
172	}
173
174	if (abiv == 1)
175		lfd = request_line_v1(cfd, offset, flags_v1, val);
176	else
177		lfd = request_line_v2(cfd, offset, flags_v2, val);
178
179	close(cfd);
180
181	if (lfd < 0) {
182		fprintf(stderr, "Failed to request %s:%d: %s\n", chip, offset, strerror(-lfd));
183		return lfd;
184	}
185
186	if (flags_v2 & GPIO_V2_LINE_FLAG_OUTPUT) {
187		wait_signal();
188	} else {
189		if (abiv == 1)
190			ret = get_value_v1(lfd);
191		else
192			ret = get_value_v2(lfd);
193	}
194
195	close(lfd);
196
197	return ret;
198}