Re: [PATCH 5/6] Staging/iio/adc/touchscreen/MXS: add interrupt driven touch detection

Hi Jonathan,

On Sunday 15 September 2013 18:10:18 Jonathan Cameron wrote:

On 09/15/13 11:56, Jonathan Cameron wrote:

quoted

On 09/11/13 09:18, Juergen Beisert wrote:

quoted

For battery driven systems it is a very bad idea to collect the
touchscreen data within a kernel busy loop.

This change uses the features of the hardware to delay and accumulate
samples in hardware to avoid a high interrupt and CPU load.

Note: this is only tested on an i.MX23 SoC yet.

Signed-off-by: Juergen Beisert <redacted>
CC: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
CC: devel-gWbeCf7V1WCQmaza687I9mD2FQJk+8+b@public.gmane.org
CC: Marek Vasut <redacted>
CC: Fabio Estevam <redacted>
CC: Jonathan Cameron <jic23-KWPb1pKIrIJaa/9Udqfwiw@public.gmane.org>

While this driver is placed in IIO within staging at the moment, these
changes are definitely input related.  Hence I have cc'd Dmitry and the
input list.

I am personaly a little uncomfortable that we have such a complex bit of
input code sat within an IIO driver but such is life.

The logic in here looks reasonable to me. I am far from a specialist in how
these touch screens are normally handled though.

One thing to note is that you really want to get a proposed device tree
spec out asap as that can take longer to review than the driver.  If you
are proposing to do that as a future patch, then take into account that
you'll need to ensure these are the defaults if it is not specified in the
device tree for ever more (which is more painful than hammering out he
device tree stuff now!)
...

Will do.

Regards,
Juergen

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