Re: [PATCH v7 07/17] iio: test: add kunit tests for channel prefix naming generation

[Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>]

On Mon, 13 Jul 2026 10:52:56 +0100
Rodrigo Alencar <455.rodrigo.alencar@gmail.com> wrote:

> On 12/07/26 02:09, Jonathan Cameron wrote:
> > On Tue, 07 Jul 2026 15:04:28 +0100
> > Rodrigo Alencar via B4 Relay <devnull+rodrigo.alencar.analog.com@kernel.org> wrote:
> >   
> > > From: Rodrigo Alencar <rodrigo.alencar@analog.com>
> > > 
> > > Add a KUnit test suite covering __iio_chan_prefix_emit(), the helper
> > > that builds IIO sysfs attribute name prefixes from an iio_chan_spec.
> > > The suite groups cases by the enum iio_shared_by mode it exercises:
> > > 
> > >   - IIO_SHARED_BY_ALL: produces an empty prefix.
> > >   - IIO_SHARED_BY_DIR: emits direction only ("in" / "out").
> > >   - IIO_SHARED_BY_TYPE: emits "<dir>_<type>" and the differential
> > >     "<dir>_<type>-<type>" variant.
> > >   - IIO_SEPARATE: covers the full matrix of indexed, differential,
> > >     modified, output and extend_name combinations, plus the two
> > >     documented error paths (differential without indexed, differential
> > >     with modifier).
> > > 
> > > A final case exercises the seq_buf overflow path by passing an
> > > undersized buffer and expects -EOVERFLOW.
> > > 
> > > Because __iio_chan_prefix_emit() is static, the test translation unit
> > > is pulled into industrialio-core.c.  
> > 
> > Isn't there some magic route cases like this that makes it non static
> > only when self tests are enabled? 
> > Claude tells me to look at include/kunit/visibility.h  
> 
> There is, Although I think that using
> 
> 	#if IS_ENABLED(CONFIG_IIO_CHANNEL_PREFIX_KUNIT_TEST)
> 		#include "test/iio-test-channel-prefix.c"
> 	#endif
> 
> was more straight forward, less invasive and easier to change than..
> 
> 	/* In "drivers/iio/industrialio-core.c" */
> 
> 	#include <kunit/visibility.h>
> 	...
> 	VISIBLE_IF_KUNIT ssize_t __iio_chan_prefix_emit(...)
> 	{
> 	...
> 	}
> 	EXPORT_SYMBOL_IF_KUNIT(__iio_chan_prefix_emit);
> 
> 	/* In "iio_core.h" */
> 
> 	#if IS_ENABLED(CONFIG_KUNIT)
> 		ssize_t __iio_chan_prefix_emit(...);
> 	#endif
> 
> 	/* In "drivers/iio/test/iio-test-channel-prefix.c" */
> 
> 	#include <kunit/visibility.h>
> 	#include <iio_core.h>
> 	...
> 	MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
> 	...
> 	// Use __iio_chan_prefix_emit() in tests

I'd rather this wasn't built into the core module.  So prefer you jump
though those hoops.

Jonathan

> 
> > 
> > Very nice.  A couple of really small additions requested inline.
> > I might well have missed where you exercised the corners requested though!
> > + I'll need an Ack from Lars for that maintainers entry. I'll guess that
> > Lars won't give one as not very active at the moment in this area.
> > 
> > Jonathan
> >   
> > > 
> > > Also, an entry is created under MAINTAINERS dedicated to tests for IIO
> > > core helpers.
> > > 
> > > Signed-off-by: Rodrigo Alencar <rodrigo.alencar@analog.com>
> > > ---
> > >  MAINTAINERS                                |   8 +
> > >  drivers/iio/industrialio-core.c            |   4 +
> > >  drivers/iio/test/Kconfig                   |  14 ++
> > >  drivers/iio/test/iio-test-channel-prefix.c | 246 +++++++++++++++++++++++++++++
> > >  4 files changed, 272 insertions(+)
> > > 
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 2b1ec46c5919..57ffc0dcfdb6 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -12634,6 +12634,14 @@ F:	include/dt-bindings/iio/
> > >  F:	include/linux/iio/
> > >  F:	tools/iio/
> > >  
> > > +IIO CORE KUNIT TESTS
> > > +M:	Lars-Peter Clausen <lars@metafoo.de>  
> > 
> > I'd need an Ack from Lars for this entry.   If we don't get one are you
> > fine looking after this without Lars listed?    
> 
> That is fine, will drop his name.
>