iio: event_monitor: report unsupported events

This makes the event monitor bail out with a helpful error
message if a device does not support events, as a related
fix to iio core now makes it return -ENODEV properly.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/tools/iio/iio_event_monitor.c b/tools/iio/iio_event_monitor.c
index cd3fd41b481dc111406e89c4ad65dd59c4dd334c..d51eb04202e915558a7a638ed6ca79a1ab8741e1 100644 (file)
--- a/tools/iio/iio_event_monitor.c
+++ b/tools/iio/iio_event_monitor.c
@@ -284,7 +284,11 @@ int main(int argc, char **argv)
        ret = ioctl(fd, IIO_GET_EVENT_FD_IOCTL, &event_fd);
        if (ret == -1 || event_fd == -1) {
                ret = -errno;
-               fprintf(stderr, "Failed to retrieve event fd\n");
+               if (ret == -ENODEV)
+                       fprintf(stderr,
+                               "This device does not support events\n");
+               else
+                       fprintf(stderr, "Failed to retrieve event fd\n");
                if (close(fd) == -1)
                        perror("Failed to close character device file");