Re: [PATCH RFC] ARM: dts: mxs: leave card detect out of common mmc pins config

Marek Vasut
2013-04-08T16:28:34Z

Dear Shawn Guo,

> On Mon, Apr 08, 2013 at 03:58:05PM +0200, Hector Palacios wrote:
> > On 04/08/2013 02:48 PM, Shawn Guo wrote:
> > >On Mon, Apr 08, 2013 at 12:12:20PM +0200, Hector Palacios wrote:
> > >>MicroSD card sockets don't usually have card detect line. This pin
> > >>is actually not needed for the MMC to work and it is more of a
> > >>platform design decission to have it.
> > >>The card detect pin already has a configuration entry of its own:
> > >>'mmc0_cd_cfg' so we complete the iomux configuration here and let
> > >>platforms to include it or not depending on whether the card detect
> > >>line is routed to the SD socket.
> > >
> > >Sounds sensible.
> > >
> > >>Signed-off-by: Hector Palacios <hector.palacios@digi.com>
> > >>---
> > >>
> > >>Hello,
> > >>
> > >>All imx28 based platforms except 'bluegiga,apx4devkit' and
> > >>'schulercontrol,imx28-sps1', use 'mmc0_cd_cfg' in their mmc
> > >>configuration so please check whether this patch would break these
> > >>platforms.
> > >
> > >I just tested the patch on imx28-evk and card-detection still works. So
> > >patches applied, thanks.
> >
> > The EVK and most platforms will work because they are using
> > 'mmc0_cd_cfg' so actually this patch does not change anything on
> > them.
> > Platforms 'bluegiga,apx4devkit' and 'schulercontrol,imx28-sps1'
> > however are not referencing 'mmc0_cd_cfg' so after applying this
> > patch they will have unconfigured CD line and they may break.
>
> Ah, yes. I thought that any board that has CD support has to reference
> 'mmc0_cd_cfg'. That's not necessarily true.
>
> > The driver will call get_cd() upon probing, which returns the status of
> > the CD line. Please check these two platforms before applying.
>
> Ok, let's wait for people owning the boards to confirm.

Maybe you want to use MMC_CAP_NEEDS_POLL as was noted by someone before on the
olinuxino -- the slot is there, it's just the CD line that's missing.

Best regards,
Marek Vasut