colibri PXA320 and UCB1400 - touch screen troubles

[Yuri Ludkevich]

2010/8/11 Marek Vasut <marek.vasut at gmail.com>

> Dne St 11. srpna 2010 12:51:25 Daniel Mack napsal(a):
> > 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?
>
> nCS3 is the chipselect for CPLD space actually (and the EXT chipselects).
> If
> it's configured as nCS3, you can write to the CPLD, but in case you don't
> need
> PCMCIA (and ext. chipselects), you should be ok either way.
>
> And as Dan said, don't mix GPIO4 and GPIO4_2 :)
>
> Yep. I know about CPLD. Our board do not use PCMCIA, only SD/MMC. So for us
it should work.

But if someone wants to use both PCMCIA and touchscreen - how to configure
this GPIOs properly?
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