From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Linus Walleij To: Jonathan Cameron , linux-iio@vger.kernel.org Cc: Linus Walleij Subject: [PATCH v2] iio: generic_buffer: be helpful about enabling channels Date: Mon, 10 Aug 2015 10:55:08 +0200 Message-Id: <1439196908-5627-1-git-send-email-linus.walleij@linaro.org> List-ID: Currently if generic_buffer is invoked without first enabling any channels in scan_elements/*_en, it will fail unable to enable the buffer because bytes_per_datum inside the kernel will be zero if no channels are available. It is implied that the user of the program should enable channels manually or with a script before executing generic_buffer. Be more helpful by stopping execution if no enabled channels can be found, and print a helptext that will tell you what is wrong and what needs to be done. Signed-off-by: Linus Walleij --- ChangeLog v1->v2: - Rebased on the "togreg" branch - Print errors to stderr as requested by Hartmut --- tools/iio/generic_buffer.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/tools/iio/generic_buffer.c b/tools/iio/generic_buffer.c index 9f7b85bf6ada..01c4f67801e0 100644 --- a/tools/iio/generic_buffer.c +++ b/tools/iio/generic_buffer.c @@ -328,6 +328,15 @@ int main(int argc, char **argv) "diag %s\n", dev_dir_name); goto error_free_triggername; } + if (!num_channels) { + fprintf(stderr, + "No channels are enabled, we have nothing to scan.\n"); + fprintf(stderr, "Enable channels manually in " + FORMAT_SCAN_ELEMENTS_DIR + "/*_en and try again.\n", dev_dir_name); + ret = -ENOENT; + goto error_free_triggername; + } /* * Construct the directory name for the associated buffer. -- 2.4.3