Re: [PATCH 10/53] Input: atmel_mxt_ts - Add memory access interface via sysfs

Mark Brown wrote:

On Fri, Jun 21, 2013 at 09:16:16AM -0700, Nick Dyer wrote:

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Mark Brown wrote:

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Yes, to be honest.  I'd hope it wouldn't be increasing the number of
read/write operations...

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For some operations it does. For example updating the whole chip config
(which is a common thing to want to do), it would turn a couple of write
operations into ~20 on recent chips.

Is that really happening on peformance critical paths other than initial
power up (which could be handled more neatly anyway).

Well, you're right that we could probably add more API for performance
critical stuff. But that wasn't your original question.

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and of course a system integrator may choose not to copy the reference
design in this respect, it does seem a bit odd after all.

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You're being a bit optimistic there. Examples of devices that require
this are Samsung Galaxy Tab 10.1, Asus Transformer TF101.

If absoluely nobody has used the separate wakeup pin then the hardware
designers are wasting a pin there...  my point isn't that nobody would
use the reference design it's that some boards will have the separate
signal.

That's entirely hypothetical, and you're wasting our time until you can
actually point to such hardware, happy to write patches to support that
mode of operation as well if you do.