Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation

From: "H. Nikolaus Schaller" <hns@goldelico.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
	"Andrey Gelman" <andrey.gelman@compulab.co.il>,
	"Michel Verlaan" <michel.verl@gmail.com>,
	"Nick Dyer" <nick@shmanahar.org>,
	"Tony Lindgren" <tony@atomide.com>,
	kernel@pyra-handheld.com, "Sebastian Reichel" <sre@kernel.org>,
	"Benjamin Tissoires" <benjamin.tissoires@redhat.com>,
	"Mauro Carvalho Chehab" <mchehab@kernel.org>,
	"Russell King" <linux@armlinux.org.uk>,
	"Aaro Koskinen" <aaro.koskinen@nokia.com>,
	"Javier Martinez Canillas" <javier@osg.samsung.com>,
	"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>,
	"Igor Grinberg" <grinberg@compulab.co.il>,
	linux-omap <linux-omap@vger.kernel.org>,
	"Petr Cvek" <petr.cvek@tul.cz>,
	"Siebren Vroegindeweij" <siebren.vroegindeweij@hotmail.com>,
	"Haibo Chen" <haibo.chen@freescale.com>,
	"Dmitry Torokhov" <dmitry.torokhov@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-iio@vger.kernel.org, "Andrew F. Davis" <afd@ti.com>,
	"Mark Brown" <broonie@kernel.org>,
	"Benoît Cousson" <bcousson@baylibre.com>,
	"Pali Rohár" <pali.rohar@gmail.com>,
	"Michael Welling" <mwelling@ieee.org>,
	"Alexander Stein" <alexander.stein@systec-electronic.com>,
	"Jonathan Cameron" <jic23@kernel.org>,
	"Mika Penttilä" <mika.penttila@nextfour.com>,
	"Discussions about the Letux Kernel"
	<letux-kernel@openphoenux.org>
Subject: Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation
Date: Mon, 20 Feb 2017 21:50:01 +0100	[thread overview]
Message-ID: <24001F85-AB58-4ADB-A7A3-1E9AD6F3E1AB@goldelico.com> (raw)
In-Reply-To: <776DC6E2-5D58-40F4-8866-39D9002EF772@goldelico.com>

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> Am 20.02.2017 um 21:22 schrieb H. Nikolaus Schaller <hns@goldelico.com>:
> 
> Hi,
> 
>> Am 20.02.2017 um 20:32 schrieb Pavel Machek <pavel@ucw.cz>:
>> 
>> Hi!
>> 
>>>> But if you have userspace that depends on touchscreen to be
>>>> calibrated... that _is_ wrong.
>>> 
>>> User-space people and real users have the opposite opinion. They
>>> prefer if a touch is plug&play. I.e. without need for calibration.
>> 
>> Some people prefer to calibrate their touchscreens; because of
>> per-device variations, that gives better precision.
>> 
>> You can pass default calibration data from device tree to kernel to
>> userland. But you can not force people to use that calibration.
> 
> Yes, you can do that if you want. I hope it became clear by the formula
> in my last mail.

Sorry this can be completely misleading, if read in conjunction with your
sentences. Brevity in answers may disturb the message.

It does not mean that you can and should force people to use that calibration...

It means that users still can do per-device calibration and do not have
to use the pre-calibration capability of the driver. Hence we called it
pre-calibration.

> 
> I just want to be able to do it the other way for those users who don't
> care about this per-device variation.
> 
> BR,
> Nikolaus
> 
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