Re: [PATCH 03/10] device property: Add fwnode_property_read_int_array()

Rob Herring
2025-04-03T16:08:21Z

On Thu, Apr 3, 2025 at 8:29 AM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Wed, Apr 02, 2025 at 06:04:13PM +0200, Remo Senekowitsch wrote:
> > On Thu Mar 27, 2025 at 9:41 AM CET, Andy Shevchenko wrote:
> > > On Wed, Mar 26, 2025 at 06:13:42PM +0100, Remo Senekowitsch wrote:
> > >> The rust bindings for reading device properties has a single
> > >> implementation supporting differing sizes of integers. The fwnode C API
> > >> already has a similar interface, but it is not exposed with the
> > >> fwnode_property_ API. Add the fwnode_property_read_int_array() wrapper.
>
> ...
>
> > >> +EXPORT_SYMBOL_GPL(fwnode_property_read_int_array);
> > >
> > > I'm not sure about this. We have a lot of assumptions in the code that the
> > > arrays beneath are only represented by the selected number of integer types.
> > > This opens a Pandora's box, e.g., reading in u24, which is not supported by
> > > the upper layers..
> > >
> > >> +int fwnode_property_read_int_array(const struct fwnode_handle *fwnode, const char *propname,
> > >> + unsigned int elem_size, void *val, size_t nval);
> >
> > Here's an alternative approach using a macro to map each integer type explicitly
> > to its corresponding read function. There are some additional changes that will
> > be necessary to make the rest work, but this is the gist of it.
>
> I don;'t know Rust to tell anything about this, but at least it feels much
> better approach.

I know a little Rust and it is much worse. It is implementing the same
code 8 times instead of 1 time just to work-around the C API.

Rob