How to add GPIO outputs to the PXA2xx MFP configuration?

[Paul Parsons]

--- On Fri, 30/3/12, Haojian Zhuang <haojian.zhuang at gmail.com> wrote:
> On Fri, Mar 30, 2012 at 6:41 PM, Paul
> Parsons <lost.distance at yahoo.com>
> wrote:
> > --- On Fri, 30/3/12, Haojian Zhuang <haojian.zhuang at gmail.com>
> wrote:
> >> On Thu, Mar 29, 2012 at 2:12 AM, Paul
> >> Parsons <lost.distance at yahoo.com>
> >> wrote:
> >> > On PXA2xx platforms, the MFP API (described
> in
> >> Documentation/arm/pxa/mfp.txt)
> >> > provides values for the following:
> >> >
> >> > 1. GPIO inputs (e.g. GPIO105_GPIO).
> >> > 2. Alternate function inputs (e.g.
> GPIO105_CIF_DD_1).
> >> > 3. Alternate function outputs (e.g.
> >> GPIO105_KP_MKOUT_2).
> >> >
> >> > It does not provide values for GPIO outputs
> (i.e. AF0
> >> outputs).
> >> >
> >> > One cannot use the macro used by the MFP API
> internally
> >> - MFP_CFG_OUT() - to
> >> > define new GPIO output values, since that
> macro is
> >> forbidden in platform code.
> >> >
> >> > Without the ability to add GPIO outputs to the
> MFP
> >> configuration, it is not
> >> > possible to drive GPIO outputs high during
> sleep mode.
> >> >
> >> > This would be useful, for example, on the
> hx4700
> >> platform, where driving the
> >> > infrared powerdown GPIO 105 high during sleep
> mode
> >> would save some mA.
> >> >
> >> > So my question is: what method should one use
> to add
> >> GPIO outputs to the MFP
> >> > configuration?
> >> >
> >> > One possible method, namely manually defining
> values in
> >> the platform code:
> >> >
> >> >        MFP_PIN_GPIO105 | MFP_AF0 |
> MFP_DIR_OUT |
> >> MFP_LPM_DRIVE_HIGH,
> >> >
> >> > is essentially no different from using the
> forbidden
> >> MFP_CFG_OUT() macro.
> >> >
> >>
> >> Does MFP_CFG_OUT() help you? This macro is defined
> in
> >> mfp-pxa2xx.h.
> >
> > Yes, MFP_CFG_OUT() does help. But it has been pointed
> out that
> > MFP_CFG_OUT() is not allowed to be used in board
> support code:
> >
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2012-February/086456.html
> >
> > Is that no longer true?
> 
> I'm sorry that I messed it. Since GPIOxx_GPIO is always
> defined as MFP_CFG_IN().
> It seems that you're blocked to specify MFP_CFG_OUT().
> 
> Actually it's not a problem. While you're using it as
> output, you must
> assign special
> usage for this pin, like some peripheral rest signal. So I
> think that
> you can define new
> macro GPIOxx_yy() in mfp-pxa27x.h, like GPIO9_HZ_CLK(). Is
> it meaningful?

The GPIO output value I wish to add is specific to the hx4700 platform;
it is not defined in any PXA27x documentation.

Is it acceptable to add such platform-specific values to the generic
mfp-pxa27x.h file?

Regards,
Paul