Re: [PATCH] mmc: dw_mmc: fix dw_mci_get_cd

[Arnd Bergmann <arnd@arndb.de>]

On Wednesday 15 January 2014 16:01:46 Russell King - ARM Linux wrote:
> On Wed, Jan 15, 2014 at 02:59:59PM +0100, Arnd Bergmann wrote:
> > On Wednesday 15 January 2014 21:56:26 zhangfei wrote:
> > > However, in our board cd =0 when card is deteced while cd=1 when card is
> > > removed.
> > > In order to mmc_gpio_get_cd return 1, MMC_CAP2_CD_ACTIVE_HIGH has to be
> > > set, as well as new property "caps2-mmc-cd-active-low".
> > > 
> > > --- a/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt
> > > +++ b/Documentation/devicetree/bindings/mmc/synopsys-dw-mshc.txt
> > > @@ -73,6 +73,8 @@ Optional properties:
> > > +* caps2-mmc-cd-active-low: cd pin is low when card active
> > > +
> > > 
> > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> > > +       if (of_find_property(np, "caps2-mmc-cd-active-low", NULL))
> > > +               pdata->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH;
> > > +
> > 
> > The MMC_CAP2_CD_ACTIVE_HIGH flag should only be required for
> > legacy platforms. With DT parsing, you can normally specify
> > the polarity of the GPIO line in the GPIO specifier in DT.
> 
> Since when?

I just looked through the bindings and found that about half
of them allow passing polarity in the gpio specifier. I thought
it was more than that and IIRC the outcome of a previous discussion
was that when the gpio controller allows passing polarity, you
should use that rather than a separate flag.

Not a problem though, since we can use the cd-inverted and
wp-inverted properties.

	Arnd