How to add GPIO outputs to the PXA2xx MFP configuration?

[Paul Parsons]

--- On Fri, 30/3/12, Igor Grinberg <grinberg at compulab.co.il> wrote:
> On 03/30/12 18:06, Paul Parsons wrote:
> > --- On Fri, 30/3/12, Igor Grinberg <grinberg at compulab.co.il>
> wrote:
> >> On 03/28/12 20:12, Paul Parsons
> >> 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,
> >>
> >> Have you tried:
> >> GPIO105_GPIO | MFP_LPM_DRIVE_HIGH,
> >> ?
> >>
> >> This way it works on other boards.
> > 
> > Hello Igor,
> > 
> > GPIO105_GPIO expands to a GPIO input -
> MFP_CFG_IN(GPIO105, AF0) -
> > not an output.
> 
> Yeah, I know... but read in mfp-pxa2xx.h, lines 6-20:
> /*
>  * the following MFP_xxx bit definitions in mfp.h are
> re-used for pxa2xx:
>  *
>  *  MFP_PIN(x)
>  *  MFP_AFx
>  *  MFP_LPM_DRIVE_{LOW, HIGH}
>  *  MFP_LPM_EDGE_x
>  *
>  * other MFP_x bit definitions will be ignored
>  *
>  * and adds the below two bits specifically for pxa2xx:
>  *
>  * bit     23 - Input/Output (PXA2xx
> specific)
>  * bit     24 - Wakeup Enable(PXA2xx
> specific)
>  */
> 
> This means, that there is no difference between: MFP_CFG_IN
> and MFP_CFG_OUT for PXA2xx.

The mfp-pxa2xx.c code says otherwise. It uses the MFP direction bit
to set the GPDR registers on entering sleep mode:

   353	static int pxa2xx_mfp_suspend(void)
   354	{
   355		int i;
        ...
   368		for (i = 0; i <= gpio_to_bank(pxa_last_gpio); i++) {
   369	
        ...
   375			GPDR(i * 32) = gpdr_lpm[i];
   376		}
   377		return 0;
   378	}

gpdr_lpm[] is initialized at startup to the current GPDR values, and
thereafter is updated by the value of the MFP_DIR_OUT bit in calls to
__mfp_config_gpio().

> The reason for this is that PXA2xx h/w does not have a
> dedicated MFP registers.
> All goes through the GPIO controller, so the whole MFP for
> PXA2xx is only to conform
> to newer "PXA" platform features...

Regards,
Paul