[PATCH v2] iio: generic_buffer: be helpful about enabling channels

[PATCH v2] iio: generic_buffer: be helpful about enabling channels

[Linus Walleij]

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 <linus.walleij@linaro.org>
---
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

Re: [PATCH v2] iio: generic_buffer: be helpful about enabling channels

[Hartmut Knaack]

Linus Walleij schrieb am 10.08.2015 um 10:55:
> 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 <linus.walleij@linaro.org>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>
> ---
> 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.
> 

Re: [PATCH v2] iio: generic_buffer: be helpful about enabling channels

[Jonathan Cameron]

On 11/08/15 19:20, Hartmut Knaack wrote:
> Linus Walleij schrieb am 10.08.2015 um 10:55:
>> 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 <linus.walleij@linaro.org>
> Acked-by: Hartmut Knaack <knaack.h@gmx.de>
Applied.  Thanks for clearing this up.

Jonathan
>> ---
>> 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.
>>
> 
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