tools: gpio: implement gpio-watch (33f0c47b) · Commits · 戴 / test

tools/gpio/.gitignore

+1 −0

Original line number	Diff line number	Diff line
		gpio-event-mon
		gpio-hammer
		gpio-watch
		lsgpio
		include/linux/gpio.h

tools/gpio/Build

+1 −0

Original line number	Diff line number	Diff line
		@@ -2,3 +2,4 @@ gpio-utils-y += gpio-utils.o
		lsgpio-y += lsgpio.o gpio-utils.o
		gpio-hammer-y += gpio-hammer.o gpio-utils.o
		gpio-event-mon-y += gpio-event-mon.o gpio-utils.o
		gpio-watch-y += gpio-watch.o

tools/gpio/Makefile

+10 −1

Original line number	Diff line number	Diff line
		@@ -18,7 +18,7 @@ MAKEFLAGS += -r

		override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include

		ALL_TARGETS := lsgpio gpio-hammer gpio-event-mon
		ALL_TARGETS := lsgpio gpio-hammer gpio-event-mon gpio-watch
		ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS))

		all: $(ALL_PROGRAMS)
		@@ -66,6 +66,15 @@ $(GPIO_EVENT_MON_IN): prepare FORCE $(OUTPUT)gpio-utils-in.o
		$(OUTPUT)gpio-event-mon: $(GPIO_EVENT_MON_IN)
		$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@

		#
		# gpio-watch
		#
		GPIO_WATCH_IN := $(OUTPUT)gpio-watch-in.o
		$(GPIO_WATCH_IN): prepare FORCE
		$(Q)$(MAKE) $(build)=gpio-watch
		$(OUTPUT)gpio-watch: $(GPIO_WATCH_IN)
		$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@

		clean:
		rm -f $(ALL_PROGRAMS)
		rm -f $(OUTPUT)include/linux/gpio.h

tools/gpio/gpio-watch.c

0 → 100644

+99 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0-only
		/*
		* gpio-watch - monitor unrequested lines for property changes using the
		* character device
		*
		* Copyright (C) 2019 BayLibre SAS
		* Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
		*/

		#include <ctype.h>
		#include <errno.h>
		#include <fcntl.h>
		#include <linux/gpio.h>
		#include <poll.h>
		#include <stdbool.h>
		#include <stdio.h>
		#include <stdlib.h>
		#include <string.h>
		#include <sys/ioctl.h>
		#include <unistd.h>

		int main(int argc, char **argv)
		{
		struct gpioline_info_changed chg;
		struct gpioline_info req;
		struct pollfd pfd;
		int fd, i, j, ret;
		char event, end;
		ssize_t rd;

		if (argc < 3)
		goto err_usage;

		fd = open(argv[1], O_RDWR \| O_CLOEXEC);
		if (fd < 0) {
		perror("unable to open gpiochip");
		return EXIT_FAILURE;
		}

		for (i = 0, j = 2; i < argc - 2; i++, j++) {
		memset(&req, 0, sizeof(req));

		req.line_offset = strtoul(argv[j], &end, 0);
		if (*end != '\0')
		goto err_usage;

		ret = ioctl(fd, GPIO_GET_LINEINFO_WATCH_IOCTL, &req);
		if (ret) {
		perror("unable to set up line watch");
		return EXIT_FAILURE;
		}
		}

		pfd.fd = fd;
		pfd.events = POLLIN \| POLLPRI;

		for (;;) {
		ret = poll(&pfd, 1, 5000);
		if (ret < 0) {
		perror("error polling the linechanged fd");
		return EXIT_FAILURE;
		} else if (ret > 0) {
		memset(&chg, 0, sizeof(chg));
		rd = read(pfd.fd, &chg, sizeof(chg));
		if (rd < 0 \|\| rd != sizeof(chg)) {
		if (rd != sizeof(chg))
		errno = EIO;

		perror("error reading line change event");
		return EXIT_FAILURE;
		}

		switch (chg.event_type) {
		case GPIOLINE_CHANGED_REQUESTED:
		event = "requested";
		break;
		case GPIOLINE_CHANGED_RELEASED:
		event = "released";
		break;
		case GPIOLINE_CHANGED_CONFIG:
		event = "config changed";
		break;
		default:
		fprintf(stderr,
		"invalid event type received from the kernel\n");
		return EXIT_FAILURE;
		}

		printf("line %u: %s at %llu\n",
		chg.info.line_offset, event, chg.timestamp);
		}
		}

		return 0;

		err_usage:
		printf("%s: <gpiochip> <line0> <line1> ...\n", argv[0]);
		return EXIT_FAILURE;
		}

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