From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751882AbdBSWaR (ORCPT ); Sun, 19 Feb 2017 17:30:17 -0500 Received: from mail.andi.de1.cc ([85.214.239.24]:50270 "EHLO h2641619.stratoserver.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751307AbdBSWaO (ORCPT ); Sun, 19 Feb 2017 17:30:14 -0500 Date: Sun, 19 Feb 2017 23:29:18 +0100 From: Andreas Kemnade To: Pavel Machek Cc: "H. Nikolaus Schaller" , Mark Rutland , Andrey Gelman , Michel Verlaan , Nick Dyer , Tony Lindgren , linux-kernel@vger.kernel.org, Benjamin Tissoires , linux-omap@vger.kernel.org, Russell King , Aaro Koskinen , Javier Martinez Canillas , Igor Grinberg , Hans Verkuil , linux-input@vger.kernel.org, devicetree@vger.kernel.org, Pali =?UTF-8?B?Um9ow6Fy?= , Arnd Bergmann , Eric Engestrom , Hans de Goede , Rob Herring , Mika =?UTF-8?B?UGVudHRpbMOk?= , Mauro Carvalho Chehab , Petr Cvek , Siebren Vroegindeweij , Haibo Chen , Dmitry Torokhov , Sebastian Reichel , linux-iio@vger.kernel.org, "Andrew F. Davis" , Mark Brown , =?UTF-8?B?QmVub8OudA==?= Cousson , kernel@pyra-handheld.com, Michael Welling , letux-kernel@openphoenux.org, Jonathan Cameron , Alexander Stein Subject: Re: [Letux-kernel] [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation Message-ID: <20170219232918.53801560@aktux> In-Reply-To: <20170219205708.GA9641@amd> References: <20170218180811.GB9377@amd> <27287BC5-E4E2-4F50-B140-C74D3CADED5B@goldelico.com> <20170218225435.GA4693@amd> <20170219141715.GA7159@amd> <05F3816F-46E6-4BC2-9E2E-F20E645F7197@goldelico.com> <20170219171518.GA12833@amd> <20170219190547.GA17292@amd> <20170219205708.GA9641@amd> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; boundary="Sig_/C6+C.W4k3c5jM8YobTOnFfb"; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Sig_/C6+C.W4k3c5jM8YobTOnFfb Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hi, On Sun, 19 Feb 2017 21:57:08 +0100 Pavel Machek wrote: > Hi! >=20 >=20 > > But as said I don't think we need float or fixed point for > > practical systems at all. >=20 > So you are going to loose precision. And if userspace decides to > calibrate it slightly differently from kernel, lost precision will > matter. >=20 > > >>> and floating point in kernel is hard. Also > > >>> you'd either have to invent new interface, or you'd break > > >>> touchscreen for people that already have their touchscreens > > >>> calibrated. > > >>=20 > > >> No, I don't break calibration for people using a different chip. > > >=20 > > > So you propose your touchscreen to behave differently from all > > > other touchscreens in tree? > >=20 > > No. I only propose that my touch screen behaves properly and in the > > best way it can. If others are worse, they should also be improved > > at some time. >=20 > Different from all other drivers. Read: broken. >=20 > No. You have to design interface such that they _can_ be improved, and > what you propose does not work that way.=20 >=20 Then the consequent way would be to use i2c directly from userspace. Because maybe for some really, really unusual you can do something better there. Maybe adjust on-chip filtering (here the MAV-filter) to interact better with your userspace filtering or something like that if you want to exactly detect where maybe a mosquito tries to drill into your touch screen (if the pressure would be enough...)=20 > > And note that I am not making things different from others in tree, > > I am making the tsc2007 right (incl. following the touchscreen > > bindings which define the touchscreen size in "Pixels"). >=20 > Your touch screen is not in any way special, so it has to behave in > the same way others do. >=20 I agree, the tsc2007 (=3Dwhat the interface provides to userspace) should not behave special, for example it should behave like the virtual touchscreen (=3Dwhat the interface provides to userspace) virtualbox gives. No need to be calibrated. Well, the internals are different. But that is what the kernel is good for, abstract such things. Conclusion: It cannot be totally wrong behavior to have pixel values there. And the generic touchscreen bindings describe the size in "Pixels" as said by Nikolaus, And here it is up to the dt to decide whether the touch screen is good enough in position so it does not need to be manually calibrated or there are chances to improve something. If there is no calibration in the dt, then nothing changes. Regards, Andreas --Sig_/C6+C.W4k3c5jM8YobTOnFfb Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJYqhxCAAoJEInxNTv1CwY0r3YP/2vYaVbdMDxMYSF4ynybSXpA kJoaxlwZ069q7OTMFAeqPrXaClcJGvRIZOD4vBskGSn1XE3a0reOS0DwfxFB3aiP blFmBIc9Noq/XeCZ9MAT7hSQN5sSn6oEu3EJnud3TXbY/Dg81FaNVUhvTXHkXG0q uF9S6ZD4rw1mTvmcV3B0uYAM1f7rDlx84nits95Hu7T/IJGbQNNh6iD+CsEywM7a IySiWoHgGdRLt/RciksvJs4rwd7FuPcxiH3i71rW+3K05qsW6F4VBh1Pb0h2D80G 5WaA5PGDCbf7dtkEGksSscOwl7RRoki/S49m6nnGekeNk3NV1Nd5fVqBf+e9V6Ht 4EuvhM4IKLnQ8V3bhrSvVaBYvQk6tekaNvuTOTjbHTUlcvlap4gc45aeYAY9EkVr ZQGP80SV5t6GaWlRiZFFAw5upr0ElhW1zV8IZppVYGWxqZ3dkvdggMFsuIsA8a4J cDiSnXaS9dR0SPhuqPpmJJwMZzI9oT7XSdNNSnLAbBfVfnZX/ADbL8YmkCw5I44f bJsXpSbSVz+ZcPwsWqs548tY8UpI1bY8NX+dOAXElfc8ubB6OK8r96m8m8PrphtX /pt1GrKHgrbHCPFtJInZqQYB8bI60qG40w+NCEpJanhyNMclKyNiNmKM1DTlruNw TN/g7U1vBf0so6kd9Pa/ =Dpus -----END PGP SIGNATURE----- --Sig_/C6+C.W4k3c5jM8YobTOnFfb--