Re: [PATCH v9 6/8] drivers:input:ads7846(+tsc2046): fix spi module table

From: Javier Martinez Canillas <javier@osg.samsung.com>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: "H. Nikolaus Schaller" <hns@goldelico.com>,
	"Mark Rutland" <mark.rutland@arm.com>,
	"Michel Verlaan" <michel.verl@gmail.com>,
	"Nick Dyer" <nick@shmanahar.org>,
	"Tony Lindgren" <tony@atomide.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"Benjamin Tissoires" <benjamin.tissoires@redhat.com>,
	linux-omap <linux-omap@vger.kernel.org>,
	"Russell King" <linux@armlinux.org.uk>,
	"Igor Grinberg" <grinberg@compulab.co.il>,
	"Hans Verkuil" <hans.verkuil@cisco.com>,
	linux-input@vger.kernel.org,
	devicetree <devicetree@vger.kernel.org>,
	"Arnd Bergmann" <arnd@arndb.de>,
	"Eric Engestrom" <eric@engestrom.ch>,
	"Hans de Goede" <hdegoede@redhat.com>,
	"Rob Herring" <robh+dt@kernel.org>,
	"Mika Penttilä" <mika.penttila@nextfour.com>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"Petr Cvek" <petr.cvek@tul.cz>,
	"Siebren Vroegindeweij" <siebren.vroegindeweij@hotmail.com>,
	"Sebastian Reichel" <sre@kernel.org>,
	linux-iio@vger.kernel.org, "Andrew F. Davis" <afd@ti.com>,
	"Mark Brown" <broonie@kernel.org>,
	"Benoît Cousson" <bcousson@baylibre.com>,
	kernel@pyra-handheld.com, "Michael Welling" <mwelling@ieee.org>,
	"Jonathan Cameron" <jic23@kernel.org>,
	"Alexander Stein" <alexander.stein@systec-electronic.com>,
	"Discussions about the Letux Kernel"
	<letux-kernel@openphoenux.org>
Subject: Re: [PATCH v9 6/8] drivers:input:ads7846(+tsc2046): fix spi module table
Date: Wed, 1 Feb 2017 19:50:16 -0300	[thread overview]
Message-ID: <8810e197-f071-5a3d-c376-8c365fb60640@osg.samsung.com> (raw)
In-Reply-To: <20170201222832.GA25554@dtor-ws>

Hello Dmitry,

On 02/01/2017 07:28 PM, Dmitry Torokhov wrote:

[snip]

>>
>> As said, changing the core is trivial. A RFC patch is [0].
>>
>> The problem is how to make sure that this change won't cause regressions
>> in existing drivers.
> 
> If the concern with drivers having I2C or SPI device table, but not OF
> device table, then I think cocinnelle could be used to scan and find
> them.
>

I don't think coccinelle is a good fit for this since you may have to look if
a DTS is using in its compatible string a device that's in an SPI table or if
a DT binding documents this device as a compatible string.

But yes I get your point and I agree that is just a matter of having a script
to look for these. Someone should have the time to write it though :)

>>
>> There was particularly tricky for the spi-nor driver, it doesn't help that
>> a lot of DT are using undocumented compatible strings (sometimes with no
>> vendor prefix). You can see the discussion here [1].
>>
>> In the same thread Mark Brown said that it wasn't that bad to have the
>> information in the OF device ID table duplicated in a SPI device table.
>>
>> Certainly isn't the best approach but IMHO is better than the module not
>> loading.
> 
> You can always build the module into kernel or load it by hand if it is
> that important. Module autoloading does not work anyway if you have
> several compatible strings, like
> 
> 	compatible = "vendor,new-device", "vendor,generic-device";
> 
> Thanks.
>

Agree.

Best regards,
-- 
Javier Martinez Canillas
Open Source Group
Samsung Research America