tarkshya
Posts: 47
Joined: Tue Nov 03, 2015 7:28 pm

official touch screen driver - ft5406 & interrupt

Mon Feb 06, 2017 7:45 pm

Hi All,


https://github.com/raspberrypi/linux/bl ... i-ft5406.c

The official touch screen driver (ft5406 controller) for Raspbian uses a polling mechanism to sample points, is there a way we can get an interrupt when a pen/touch event happens ? or is the pen/touch interrupt not accessible at all?


Thanks
Tarkshya

dwelch67
Posts: 961
Joined: Sat May 26, 2012 5:32 pm

Re: official touch screen driver - ft5406 & interrupt

Mon Feb 06, 2017 10:08 pm

this is a bare metal forum.

tarkshya
Posts: 47
Joined: Tue Nov 03, 2015 7:28 pm

Re: official touch screen driver - ft5406 & interrupt

Mon Feb 06, 2017 10:27 pm

Hi,

Sorry for the confusion.

The question am asking is not specific to any OS. The reference link is just for clarification on how the touchscreen driver is sampling things, infact most of the code has been adapted by others (for e.g. ultibo) to write their own drivers.

My point is to get the interrupt from the ft5406 controller, and i presume thats not OS specific.

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Ultibo
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Location: Australia
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Re: official touch screen driver - ft5406 & interrupt

Mon Feb 06, 2017 11:21 pm

tarkshya wrote:is there a way we can get an interrupt when a pen/touch event happens ? or is the pen/touch interrupt not accessible at all?
As far as I can tell there is no interrupt available from the official touchscreen controller to the ARM, the interface provided is generated completely by the GPU and has very little in common with the actual FT5406 interface.

If an interrupt is occurring (quite possible) it is being consumed by the GPU and is not exposed anywhere.

The good thing is the interface works fine in bare metal, the only limitation is that because it is polled you really need some form of threading available to make use of it.
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https://ultibo.org

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tarkshya
Posts: 47
Joined: Tue Nov 03, 2015 7:28 pm

Re: official touch screen driver - ft5406 & interrupt

Tue Feb 07, 2017 3:32 am

@ultibo: thanks for the clarification

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