Messages in this thread | | | From | Andy Shevchenko <> | Date | Thu, 5 Dec 2019 00:42:39 +0200 | Subject | Re: [PATCH v2 11/11] tools: gpio: implement gpio-watch |
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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
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