Re: [PATCH] spi: Force the registration of the spidev devices

From: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Martin Sperl <kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>
Cc: Maxime Ripard
	<maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>,
	Alexandre Belloni
	<alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>,
	linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] spi: Force the registration of the spidev devices
Date: Wed, 30 Apr 2014 18:21:23 -0700	[thread overview]
Message-ID: <20140501012123.GG3245@sirena.org.uk> (raw)
In-Reply-To: <DA3907EB-0C1B-42FB-B288-9E33F6E24E3E-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org>

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On Wed, Apr 30, 2014 at 10:00:18PM +0200, Martin Sperl wrote:
> 
> On 30.04.2014, at 20:14, Maxime Ripard <maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org> wrote:

> > I'd really be in favor of using the DT overlays for this. All this is
> > nice, but very fragile. You can't really handle any weird
> > configurations that you might encounter, like weird interrupt
> > controllers that might be requiring more informations, or you don't
> > set any interrupt parents, and this parameter list will basically be
> > an ever-growing list of parameters to deal with all kind of crazy
> > corner-cases, and I'm not sure it's something we want.

> Problem is getting DT overlays included in the kernel it seems...

We should fix that and solve this problem for all kinds of devices (and
some other similar use cases like the FPGAs).

> Following your argument we should not have this interface either
> but use DT for these GPIOs as well - similar argument for I2C...

> Still we have them and they are heavily used by those dev-boards,
> so why not something along the same lines also for SPI?

Those are legacy things, their presence doesn't mean they're a good
idea.  If there's problems with the userspace tooling for using overlays
when they get merged then that's the layer to fix things.

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