Re: [PATCH 28/57] media: Add ovxxxx_16bit_addr_reg_helpers.h

Laurent Pinchart
2023-02-09T10:34:45Z

Hi Andy,

On Wed, Feb 08, 2023 at 07:31:43PM +0200, Andy Shevchenko wrote:
> On Wed, Feb 8, 2023 at 6:04 PM Laurent Pinchart wrote:
> > On Wed, Feb 08, 2023 at 05:50:26PM +0200, Andy Shevchenko wrote:
> > > On Wed, Feb 8, 2023 at 5:41 PM Laurent Pinchart wrote:
> > > > On Wed, Feb 08, 2023 at 01:27:37PM +0200, Andy Shevchenko wrote:
> > > > > On Wed, Feb 8, 2023 at 11:52 AM Laurent Pinchart wrote:
> > > > > > On Mon, Jan 23, 2023 at 01:51:36PM +0100, Hans de Goede wrote:
>
> ...
>
> > > > > > > Add a new ovxxxx_16bit_addr_reg_helpers.h header file with static inline
> > > > > > > versions of these register access helpers, so that this code duplication
> > > > > > > can be removed.
> > > > > >
> > > > > > Any reason to hand-roll those instead of using regmap ? Also, may I
> > > > > > suggest to have a look at drivers/media/i2c/imx290.c
> > > > >
> > > > > While this is a bit error prone example, a patch is on its way, ...
> > > >
> > > > The two cleanups are nice, but they're cleanup, not error fixes :-)
> > >
> > > It depends on which side you look at it. I admit I haven't dug into
> > > the code to see if endianess can be an issue there, but the code
> > > itself is not written well, esp. when one offers it as an example. So
> > > definitely there is a fix on the upper layer.
> >
> > Did I miss something ? Your two patches replace a tiny amount of code
> > with helper functions that don't change any behaviour. It's nicer with
> > those helpers, no question about that, but "not written well" is a bit
> > of a stretch and feels quite insulting.
>
> Sorry for your feelings, what I meant is the pure educational purposes
> of the example. When one takes the mentioned driver as an example and
> uses the code in a slightly different environment the endianess issue
> may become a real one. That's why we have helpers in kernel to improve
> robustness against blind copy'n'paste approach. It does not mean your
> code is broken per se.

Reference code should be pristine as much as possible, no disagreement
there. That's why I think your two patches are good :-)

> > Feel free to submit patches that
> > add new "well-written" helpers.

--
Regards,

Laurent Pinchart