ATMEL MXT224 Touch Controller

ATMEL MXT224 Touch Controller

[Poddar, Sourav]

Hi,

Did anyone have tried using atmel touchscreen controller
 driver (drivers/input/touchscreen/atmel_mxt_ts.c) for atmel mxt224 chip?

~Sourav

Re: ATMEL MXT224 Touch Controller

[Poddar, Sourav]

Hi Daniel,

On Thu, May 31, 2012 at 12:04 AM, Daniel Kurtz <djkurtz@chromium.org> wrote:
>
>
> On Tue, May 29, 2012 at 7:16 AM, Poddar, Sourav <sourav.poddar@ti.com>
> wrote:
>>
>> Hi,
>>
>> Did anyone have tried using atmel touchscreen controller
>>  driver (drivers/input/touchscreen/atmel_mxt_ts.c) for atmel mxt224 chip?
>

>
> Yes.  It works pretty well for us.
>
Thanks for the reply.

The issue which I am facing is that there are many interrupts that comes during
the probe and it keeps coming after bootup even if I dont touch the touch panel.

One point which I want to clarify is the use of the RESET pin in the
controller. If I dont do a "RESET", the probe fails at the first i2c read/write.
I am doing this reset of the touchscreen controller in my board file
by the use of
a particular gpio. Are you also doing a RESET ?

I saw a lot of patches from you on this driver, which are not there in
mainline yet.
Are you using any local patches also?

Is it possible for you to share your touchscreen configuration
parameters as there
might be some parameters which I might be configuring wrong?

Any pointer on above point will be really helpful.

~Sourav


>>
>>
>> ~Sourav
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Re: ATMEL MXT224 Touch Controller

[Nick Dyer]

> The issue which I am facing is that there are many interrupts that comes
> during the probe and it keeps coming after bootup even if I dont touch
> the touch panel.

It sounds like your configuration may need tuning.

> One point which I want to clarify is the use of the RESET pin in the 
> controller. If I dont do a "RESET", the probe fails at the first i2c
> read/write. I am doing this reset of the touchscreen controller in my
> board file by the use of a particular gpio. Are you also doing a RESET

Try putting in a delay before the first read, eg 500ms. It may be that the
chip is not ready, it takes some time to settle after power on.

> I saw a lot of patches from you on this driver, which are not there in 
> mainline yet. Are you using any local patches also?

Daniel does have some other stuff that hasn't been merged yet.

You will also find some official atmel kernel updates, and some useful
utilities here:
https://github.com/atmel-maxtouch

It would be desirable to push this work upstream, I don't know of any
manufacturer which is shipping the unchanged mainline kernel, most of them
have diverged considerably.

> Is it possible for you to share your touchscreen configuration 
> parameters as there might be some parameters which I might be
> configuring wrong?
> 
> Any pointer on above point will be really helpful.

I don't know what platform you are working on, but if you contact your
Atmel sales representatives they can provide you with the protocol guide
documentation on the tuning parameters. It generally requires an NDA.

cheers
-- 
Nick Dyer
Software Engineer, ITDev Ltd
Hardware and Software Development Consultancy
Website: http://www.itdev.co.uk

Re: ATMEL MXT224 Touch Controller

[Yufeng Shen]

On Tue, Jun 5, 2012 at 3:41 PM, Nick Dyer <nick.dyer@itdev.co.uk> wrote:
>> The issue which I am facing is that there are many interrupts that comes
>> during the probe and it keeps coming after bootup even if I dont touch
>> the touch panel.
>
> It sounds like your configuration may need tuning.
>

Your platform may have too much interfering noise that causes false touch
reports.

>> One point which I want to clarify is the use of the RESET pin in the
>> controller. If I dont do a "RESET", the probe fails at the first i2c
>> read/write. I am doing this reset of the touchscreen controller in my
>> board file by the use of a particular gpio. Are you also doing a RESET
>
> Try putting in a delay before the first read, eg 500ms. It may be that the
> chip is not ready, it takes some time to settle after power on.
>
>> I saw a lot of patches from you on this driver, which are not there in
>> mainline yet. Are you using any local patches also?
>
> Daniel does have some other stuff that hasn't been merged yet.
>
> You will also find some official atmel kernel updates, and some useful
> utilities here:
> https://github.com/atmel-maxtouch
>
> It would be desirable to push this work upstream, I don't know of any
> manufacturer which is shipping the unchanged mainline kernel, most of them
> have diverged considerably.
>

Chromium port of the atmel_mxt_ts can be found here

http://git.chromium.org/gitweb/?p=chromiumos/third_party/kernel.git;a=blob;f=drivers/input/touchscreen/atmel_mxt_ts.c;h=f11b3c46f82de8fea5a82674ef14e51801e8e3f5;hb=refs/heads/chromeos-3.4


>> Is it possible for you to share your touchscreen configuration
>> parameters as there might be some parameters which I might be
>> configuring wrong?
>>

Open source sample of 224e/s configuration data can be found here
http://git.chromium.org/gitweb/?p=chromiumos/third_party/kernel.git;a=blob;f=drivers/platform/x86/chromeos_laptop.c;h=8cec113768a46313b612c0fd0155ddd2bdd389fb;hb=refs/heads/chromeos-3.4

>> Any pointer on above point will be really helpful.
>
> I don't know what platform you are working on, but if you contact your
> Atmel sales representatives they can provide you with the protocol guide
> documentation on the tuning parameters. It generally requires an NDA.
>
> cheers
> --
> Nick Dyer
> Software Engineer, ITDev Ltd
> Hardware and Software Development Consultancy
> Website: http://www.itdev.co.uk