From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Kent Gibson <warthog618@gmail.com>,
Linus Walleij <linus.walleij@linaro.org>,
"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Bartosz Golaszewski <bgolaszewski@baylibre.com>
Subject: Re: [PATCH v2 11/11] tools: gpio: implement gpio-watch
Date: Thu, 5 Dec 2019 00:42:39 +0200 [thread overview]
Message-ID: <CAHp75VcqYsKUzxGUhn8aHg_u-B=FkqmTU2YS+yyVNfAPu+715w@mail.gmail.com> (raw)
In-Reply-To: <20191204155941.17814-2-brgl@bgdev.pl>
On Wed, Dec 4, 2019 at 7:19 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> Add a simple program that allows to test the new LINECHANGED_FD ioctl().
> --- a/tools/gpio/.gitignore
> +++ b/tools/gpio/.gitignore
> @@ -1,4 +1,5 @@
> gpio-event-mon
> gpio-hammer
> lsgpio
> +gpio-watch
Perhaps keep it sorted?
> +++ b/tools/gpio/gpio-watch.c
> @@ -0,0 +1,112 @@
> +// 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>
> +
> +static bool isnumber(const char *str)
> +{
> + size_t sz = strlen(str);
> + int i;
> +
> + for (i = 0; i < sz; i++) {
> + if (!isdigit(str[i]))
> + return false;
> + }
> +
> + return true;
> +}
strtoul() will do the same.
char *p;
unsigned long dummy; // do we need it?
dummy = strtoul(..., &p);
return *p == '\0';
> +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;
> + 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++) {
> + if (!isnumber(argv[j]))
> + goto err_usage;
> +
> + memset(&req, 0, sizeof(req));
> + req.line_offset = atoi(argv[j]);
Oh, why not to call strtoul() directly?
> +
> + ret = ioctl(fd, GPIO_GET_LINEINFO_WATCH_IOCTL, &req);
> + if (ret) {
> + perror("unable to set up line watch");
Don't you need to unwatch previously added ones?
> + return EXIT_FAILURE;
> + }
> + }
> + 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;
> + }
Shouldn't we handle the -EINTR?
> + }
> + }
> +
> + return 0;
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2019-12-04 22:42 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-04 15:59 [PATCH v2 10/11] gpiolib: add new ioctl() for monitoring changes in line info Bartosz Golaszewski
2019-12-04 15:59 ` [PATCH v2 11/11] tools: gpio: implement gpio-watch Bartosz Golaszewski
2019-12-04 22:42 ` Andy Shevchenko [this message]
2019-12-05 9:45 ` Bartosz Golaszewski
2019-12-05 9:44 ` Kent Gibson
2019-12-05 9:48 ` Bartosz Golaszewski
2019-12-04 22:34 ` [PATCH v2 10/11] gpiolib: add new ioctl() for monitoring changes in line info Andy Shevchenko
2019-12-05 9:42 ` Bartosz Golaszewski
2019-12-05 10:27 ` Andy Shevchenko
2019-12-05 13:47 ` Bartosz Golaszewski
2019-12-05 17:02 ` Andy Shevchenko
2019-12-06 21:20 ` Bartosz Golaszewski
2019-12-10 17:00 ` Andy Shevchenko
2019-12-19 13:05 ` Bartosz Golaszewski
2019-12-19 13:12 ` Kent Gibson
2019-12-19 13:17 ` Bartosz Golaszewski
2019-12-05 10:47 ` Kent Gibson
2019-12-05 10:50 ` Bartosz Golaszewski
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