colibri PXA320 and UCB1400 - touch screen troubles

[Daniel Mack]

On Wed, Aug 11, 2010 at 02:46:15PM +0400, Yuri Ludkevich wrote:
> 2010/8/11 Daniel Mack <daniel at caiaq.de>
> > On Wed, Aug 11, 2010 at 02:08:10PM +0400, Yuri Ludkevich wrote:
> > > 2010/8/11 Daniel Mack <daniel at caiaq.de>
> > > > Yes, they are aliases to the signals without the "_2" suffix. Quoting
> > > > the PXA reference manual, chapter 5.3:
> > > >
> > > > GPIO<6_0>_2:
> > > >
> > > > General-Purpose IO Ports, second instantiation. The same signals as
> > > > GPIO<6:0>, but they are given separate names because they are
> > configured
> > > > on separate multi-function pins. The recommended configuration is for
> > > > both multi-function pin instantiations of these GPIOs not to be
> > > > configured simultaneously for GPIO functionality. The preferred
> > > > configuration for dual instantiation GPIO usage (that is, using both
> > > > GPIO<6:0> and GPIO<6:0>_2 functions) is to configure one multi-function
> > > > pin as a GPIO and the second multi-function pin instantiation for an
> > > > alternate function other than a GPIO function. Configuring GPIO<6:0> to
> > > > be present on two separate multi-function pins is not recommended.
> > > > However, when GPIO<6:0> is configured as an output and both
> > > > multi-function pin instantiations are programmed for GPIO function, the
> > > > primary and secondary instantiation of the multi-function pins are both
> > > > outputs from the common GGPIO<6:0> signal. However, when GPIO<6:0> is
> > an
> > > > input, the inputs from both multi-function pin instantiations are ORed
> > > > together before the result is sent to the internal GPIO<6:0> input
> > > > logic.
> > >
> > > Hmmm. I found with pxaregs tool what both GPIO4 and GPIO4_2 configured as
> > > GPIO. May be this cause irq autodetection to fail?
> >
> > No - if you don't tell the driver which GPIO the interrupt line is
> > connected to, it can't know. But as the reference manual says, such
> > configurations should be avoided.
> >
> > You're welcome to come up with a patch :)
> >
> > Daniel
> >
> I configure GPIO4 pin as nCS3 (alternate function #1) in colibri-pxa320.c
> and after that irq autoprobing found valid irq for UCB1400. So touchscreen
> now working just fine.

Good. Can you share a patch?

> May be I need to check other second instantiation pins for same thing?

Sure, double-checking can't harm. If you find anything, feel free to fix
it up.

Just make sure you read Documentation/SubmittingPatches in order to
avoid the most common pitfalls :)

Thanks,
Daniel