Re: [PATCH v1 07/10] spi: pxa2xx: Provide num-cs for Sharp PDAs via device properties

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Daniel Mack <daniel@zonque.org>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	Russell King <linux@armlinux.org.uk>
Subject: Re: [PATCH v1 07/10] spi: pxa2xx: Provide num-cs for Sharp PDAs via device properties
Date: Tue, 26 Mar 2024 20:50:04 +0200	[thread overview]
Message-ID: <ZgMY3AeC1Jnh1Oru@smile.fi.intel.com> (raw)
In-Reply-To: <dcdf8c46-acdc-466d-afc6-caf0e0fa39e8@sirena.org.uk>

On Tue, Mar 26, 2024 at 06:21:48PM +0000, Mark Brown wrote:
> On Tue, Mar 26, 2024 at 08:07:57PM +0200, Andy Shevchenko wrote:
> 
> > Since driver can parse num-cs device property, replace platform data
> > with this new approach.
> 
> But why?

To be able to hide the header's contents from public.
Should I update the commit message?

...

> > +static const struct property_entry spitz_spi_properties[] = {
> > +	PROPERTY_ENTRY_U32("num-cs", 3),
> > +	{ }
> > +};
> 
> This is just platform data with less validation AFAICT.

I'm not sure what validation you are expecting here. It should be done via
DT schema ideally when the platform gets converted to DT. This change is
an interim to that (at least it makes kernel side better). After the platform
code may be gone completely or converted. If the latter happens, we got
the validation back.

In any case it's not worse than plain DT property handling in the kernel.
The validation in that case is done elsewhere. Since the property is defined
in board files the assumed validation is done during development/review
stages. But OTOH for the legacy code we need not to touch the property
provider more than once. We are _not_ expecting this to be spread.

-- 
With Best Regards,
Andy Shevchenko

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