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

[Dr. H. Nikolaus Schaller]

Am 15.01.2015 um 19:16 schrieb Dmitry Torokhov <dmitry.torokhov at 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 at 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.

ok.

> 
>> 
>> 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.

ok, that should not be too difficult to add.

So we will modify our driver to use the new functions and align omap3-gta04.dtsi accordingly.

BR,
Nikolaus