Re: [PATCH 1/3] input: tsc2007: Add pre-calibration, flipping and rotation

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Thu, Jan 15, 2015 at 05:14:38PM +0100, Dr. H. Nikolaus Schaller wrote:
> 
> Am 15.01.2015 um 15:38 schrieb Sebastian Reichel <sre@kernel.org>:
> 
> > Hi,
> > 
> > On Thu, Jan 15, 2015 at 08:36:44AM +0100, Dr. H. Nikolaus Schaller wrote:
> >>> 1. Perform conversion in input core rather than individual drivers. I
> >>> think we should allocate a new bitmaps for some transformations and have
> >>> the code do X/Y flip/clip of the coordinates.
> >> 
> >> Do you have a suggestion where this should be (I have no clue how
> >> the input system works or is structured - we just know how to extend a
> >> driver that uses it)?
> >> 
> >>> 2. Standardize on bindings. We already have of-touchscreen.c doing
> >>> rudimentary parsing, we shoudl look into extending it rather than
> >>> creating myriad of driver-specific bindings.
> >> 
> >> Ok, looks reasonable.
> > 
> > Documentation is in 
> > 
> > Documentation/devicetree/bindings/input/touchscreen/touchscreen.txt
> 
> I did look into it now. Unfortunately, it does not fit well into my view of how bindings
> should be. They should describe hardware (as we are told for many other kernel
> subsystems).
> 
> Pixels and resolutions are IMHO related to the screen it is glued on - and that is
> quite independent.

Well, I think pixels was the wrong word to be used there. It is meant to
be native units, as opposed to millimeters, inches, points, etc.

> 
> So I don’t see how they do describe the different ways the touch screen can be
> wired to a tsc2007 controller.
> 
> Please can you add minimum and maximum properties for us?
> 
> Then, inverted-x and inverted-y is redundant because it is the same as having
> an expected higher value from the ADC for the minimum coordinate and a lower
> for the maximum.

I'd rather not add minimum and maximum, but add the touchscreen-start-x and
touchscreen-start-y instead so that we limit the number of obsolete
properties.

Thanks.

-- 
Dmitry
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