Re: [PATCH] IIO: Documentation: generic_buffer example: scan_size must be bytes_per_datum

[Michael Hennerich <michael.hennerich@analog.com>]

On 02/22/2011 07:48 PM, Jonathan Cameron wrote:
> On 02/15/11 14:46, michael.hennerich@analog.com wrote:
>   
>> From: Michael Hennerich <michael.hennerich@analog.com>
>>
>> In case a timestamp is present, scan size returned by size_from_channelarray()
>> is not longer valid.
>>     
> Really?  Shouldn't the timestamp just be picked up as another channel assuming
> all the relevant attributes are present (which they should be...)
>   
I think the pronunciation is on 'should be'.
Looks like all my drivers don't do it, as well as some of yours.

My assumption was that bytes_per_datum must be properly set.
And that the timestamp is always assumed to be the last 8bytes aligned
on a 64-bit boundary.
I guess some drivers need fixing.
 
>   
>> However size_from_channelarray() must be still called
>> in order to setup locations within the buffer.
>>
>> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
>> ---
>>  drivers/staging/iio/Documentation/generic_buffer.c |    8 +++++++-
>>  1 files changed, 7 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/staging/iio/Documentation/generic_buffer.c b/drivers/staging/iio/Documentation/generic_buffer.c
>> index 131d9d0..c382452 100644
>> --- a/drivers/staging/iio/Documentation/generic_buffer.c
>> +++ b/drivers/staging/iio/Documentation/generic_buffer.c
>> @@ -226,7 +226,13 @@ int main(int argc, char **argv)
>>       ret = write_sysfs_int("enable", buf_dir_name, 1);
>>       if (ret < 0)
>>               goto error_free_buf_dir_name;
>> -     scan_size = size_from_channelarray(infoarray, num_channels);
>> +
>> +     scan_size = read_sysfs_posint("bytes_per_datum", buf_dir_name);
>> +     if (ret < 0)
>> +             goto error_free_buf_dir_name;
>> +
>> +     size_from_channelarray(infoarray, num_channels);
>> +
>>       data = malloc(scan_size*buf_len);
>>       if (!data) {
>>               ret = -ENOMEM;
>>     
>   


-- 
Greetings,
Michael

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