[Letux-kernel] [PATCH v3 3/8] drivers:input:tsc2007: add iio interface to read external ADC input, temperature and raw conversion values

H. Nikolaus Schaller hns at goldelico.com
Sat Sep 24 19:51:01 CEST 2016


Hi Dmitry,

> Am 24.09.2016 um 19:44 schrieb Dmitry Torokhov <dmitry.torokhov at gmail.com>:
> 
> On Sat, Sep 24, 2016 at 10:07 AM, H. Nikolaus Schaller
> <hns at goldelico.com> wrote:
>> Hi Jonathan,
>> 
>>> Am 24.09.2016 um 18:07 schrieb Jonathan Cameron <jic23 at kernel.org>:
>>> 
>>> On 23/09/16 13:41, H. Nikolaus Schaller wrote:
>>>> The tsc2007 chip not only has a resistive touch screen controller but
>>>> also an external AUX adc imput which can be used for an ambient
>>>> light sensor, battery voltage monitoring or any general purpose.
>>>> 
>>>> Additionally it can measure the chip temperature.
>>>> 
>>>> This extension provides an iio interface for these adc channels
>>>> in addition to the raw x, y, z values and the estimated touch
>>>> screen resistance. This can be used for debugging or special
>>>> applications.
>>> I'm unconvinced that exposing the touch related channels is terribly
>>> useful.
>> 
>> Mostly for debugging of if someone wants to do a (better) touch detection

s/of/or/

>> in user space.
> 
> For that we should probably export data as a heat map via V4L2
> interface, similarly to what Nick Dyer did for Synaptics and Atmel
> drivers (albeit their heatmap functions are too slow for real
> processing and only suitable for debug/validation).

Sorry for my ignorance, but what is a heat map?
Does it allow to cat /sys/bus/something the raw values?

And why introduce another interface if we already get the iio that
easily reports such values by just adding more channels and some
lines of code?

BR,
Nikolaus



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