On 12/05/2017 07:11 PM, Matthew Fornero wrote: > On Tue, Dec 5, 2017 at 10:08 AM Lars-Peter Clausen <lars@xxxxxxxxxx> wrote: >>> What about the case when the data_available element in >>> iio_buffer_access_funcs is undefined (e.g. industrialio-buffer-cb)? >>> Do we modify iio_buffer_data_available() to return 0, do we make the >>> sysfs function return -ENOENT or -EINVAL, or simply not expose the sysfs >>> interface for this case? >> >> The callback buffer does not support any of the interfaces required for the >> userspace facing side. E.g. there is no read() callback. >> >> For proper support of the userspace interfaces data_available() is required, >> otherwise read() would never return. So I think this is fine, we'd never >> register the userspacing interface if it didn't have the data_available >> callback. > > So there should already be provisions in place for *not* registering the > cb buffer with user-space, meaning no additional logic would be required > for exposing / not exposing a "data_available" sysfs attribute, correct? Yes. -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
