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Date: Mon, 20 Feb 2017 23:21:37 +0100 From: Petr Cvek <petr.cvek@....cz> To: Dmitry Torokhov <dmitry.torokhov@...il.com>, "H. Nikolaus Schaller" <hns@...delico.com> Cc: Pali Rohár <pali.rohar@...il.com>, Sebastian Reichel <sre@...nel.org>, Mark Rutland <mark.rutland@....com>, Benoît Cousson <bcousson@...libre.com>, Tony Lindgren <tony@...mide.com>, Russell King <linux@...linux.org.uk>, Arnd Bergmann <arnd@...db.de>, Michael Welling <mwelling@...e.org>, Mika Penttilä <mika.penttila@...tfour.com>, Javier Martinez Canillas <javier@....samsung.com>, Igor Grinberg <grinberg@...pulab.co.il>, "Andrew F. Davis" <afd@...com>, Mark Brown <broonie@...nel.org>, Jonathan Cameron <jic23@...nel.org>, Rob Herring <robh+dt@...nel.org>, Alexander Stein <alexander.stein@...tec-electronic.com>, Eric Engestrom <eric@...estrom.ch>, Hans de Goede <hdegoede@...hat.com>, Benjamin Tissoires <benjamin.tissoires@...hat.com>, Mauro Carvalho Chehab <mchehab@...nel.org>, Hans Verkuil <hans.verkuil@...co.com>, Nick Dyer <nick@...anahar.org>, Siebren Vroegindeweij <siebren.vroegindeweij@...mail.com>, Michel Verlaan <michel.verl@...il.com>, "linux-input@...r.kernel.org" <linux-input@...r.kernel.org>, "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>, lkml <linux-kernel@...r.kernel.org>, Linux OMAP Mailing List <linux-omap@...r.kernel.org>, Discussions about the Letux Kernel <letux-kernel@...nphoenux.org>, linux-iio@...r.kernel.org, kernel@...a-handheld.com, Aaro Koskinen <aaro.koskinen@...ia.com>, Pavel Machek <pavel@....cz>, Andrey Gelman <andrey.gelman@...pulab.co.il>, Haibo Chen <haibo.chen@...escale.com> Subject: Re: [PATCH v9 1/8] drivers:input:tsc2007: add new common binding names, pre-calibration, flipping and rotation Hi, Dne 20.2.2017 v 22:50 Dmitry Torokhov napsal(a): > On Mon, Feb 20, 2017 at 1:27 PM, H. Nikolaus Schaller <hns@...delico.com> wrote: >> >>> Am 20.02.2017 um 22:08 schrieb Pali Rohár <pali.rohar@...il.com>: >>> >>> On Monday 20 February 2017 20:42:15 Pali Rohár wrote: >>>> Hi Nikolaus! >>>> >>>> On Monday 20 February 2017 17:50:04 H. Nikolaus Schaller wrote: >>>>> Hi Dmitry, >>>>> >>>>>> Input driver may set resolution for given axis in units per mm >>>>>> (or units per radian for rotational axis ABS_RX, ABS_RY, >>>>>> ABS_RZ), and if you check the binding, you can use >>>>>> "touchscreen-x-mm" and "touchscreen-y-mm" to specify the size of >>>>>> entire touch surface and set resolution from it so that >>>>>> userspace can calculate the proper scaling factor. >>>>> >>>>> How is this information exposed by the kernel to user-space? By >>>>> scanning the DT file or tree? >>>> >>>> Set input_abs_set_res() from kernel. And in userspace call EVIOCGABS >>>> ioctl() on input device. Look at struct input_absinfo, you should >>>> have all needed information here. This is generic input interface, >>>> no DT is needed. >>> >>> Looking at kernel code... via EVIOCSABS ioctl() you can even set >>> resolution from userspace for specified input device. >>> >>> So this could be potentially used for calibrating input device from >>> userspace? (In case DT data will not fully match current HW) >>> >>>> I hope that XServer is already using it for evdev devices... >>>> >>>> For whole implementation look at evtest program. That should be good >>>> starting point for your userspace implementation. >>>> >>>> While I'm watching this discussion... in my opinion kernel should >>>> just invert input axes (when needed) >> >> It is questionable why it should do that at all then. > > Because the task of the kernel is to provide unified view of the > hardware. Axis swapping and inversion is needed to that "up" is always > "up" and "right" is always "right". Actually my Xorg calibration 3x3 matrix is fine with both axis inverted (on TSC2046). best regards, Petr
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