Re: [PATCH 1/2] input: touchscreen: fix spelling mistake in TSC/ADC DT binding

From: Felipe Balbi <balbi@ti.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Felipe Balbi <balbi@ti.com>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	"dmitry.torokhov@gmail.com" <dmitry.torokhov@gmail.com>,
	"rob.herring@calxeda.com" <rob.herring@calxeda.com>,
	Pawel Moll <Pawel.Moll@arm.com>,
	"swarren@wwwdotorg.org" <swarren@wwwdotorg.org>,
	"ijc+devicetree@hellion.org.uk" <ijc+devicetree@hellion.org.uk>,
	"rob@landley.net" <rob@landley.net>,
	"bcousson@baylibre.com" <bcousson@baylibre.com>,
	Tony Lindgren <tony@atomide.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Linux OMAP Mailing List <linux-omap@vger.kernel.org>,
	"linux-input@vger.kernel.org" <linux-input@vger.kernel.org>
Subject: Re: [PATCH 1/2] input: touchscreen: fix spelling mistake in TSC/ADC DT binding
Date: Fri, 15 Nov 2013 11:53:56 -0600	[thread overview]
Message-ID: <20131115175356.GJ4698@saruman.home> (raw)
In-Reply-To: <20131115155540.GF24831@e106331-lin.cambridge.arm.com>

[-- Attachment #1: Type: text/plain, Size: 2156 bytes --]

Hi,

On Fri, Nov 15, 2013 at 03:55:40PM +0000, Mark Rutland wrote:
> > > > > > diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
> > > > > > index e1c5300..b61df9d 100644
> > > > > > --- a/drivers/input/touchscreen/ti_am335x_tsc.c
> > > > > > +++ b/drivers/input/touchscreen/ti_am335x_tsc.c
> > > > > > @@ -348,9 +348,16 @@ static int titsc_parse_dt(struct platform_device *pdev,
> > > > > >  	if (err < 0)
> > > > > >  		return err;
> > > > > >  
> > > > > > -	err = of_property_read_u32(node, "ti,coordiante-readouts",
> > > > > > +	/*
> > > > > > +	 * try with new binding first. If it fails, still try with
> > > > > > +	 * bogus, miss-spelled version.
> > > > > > +	 */
> > > > > > +	err = of_property_read_u32(node, "ti,coordinate-readouts",
> > > > > >  			&ts_dev->coordinate_readouts);
> > > > > >  	if (err < 0)
> > > > > > +		err = of_property_read_u32(node, "ti,coordiante-readouts",
> > > > > > +				&ts_dev->coordinate_readouts);
> > > > > > +	if (err < 0)
> > > > > >  		return err;
> > > > > 
> > > > > Thanks, very good. Do we keep this fallback for ever or just for a year
> > > > > or two?
> > > > 
> > > > That's for DT maintainers to decide but considering DT is an ABI, I
> > > > guess we need to keep for 30 years or so :-p
> > > 
> > > We keep it as long as we have to. If no-one's relying on the typo by the
> > > next merge window, I see no reason we'd have to keep support for the
> > 
> > and how could you know that ? considering it's an ABI, how could you
> > ever know that ?
> 
> If you know that the only user of a binding is a dts for a particular
> product that you're in charge of, then you'd know the set of kernel +
> dtb combinations out there, and can judge.

once the binding has made into mainline, it's next to impossible to
figure out who has downloaded a tarball containing that driver and made
a product out of it.

Besides keeping that check in the driver won't hurt at all in the long
run. I would give it at least until 4.0 before thinking about removing,
and that might still not be enough time.

-- 
balbi

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 836 bytes --]