Adding esdhc4 eMMC support on mx6sabresd

[Dong Aisheng]

On Thu, May 08, 2014 at 09:18:35AM +0200, Lothar Waßmann wrote:
> Hi,
> 
> Fabio Estevam wrote:
> > Hi Dong,
> > 
> > I have tested the following patch to add support for the emmc port on
> > mx6qsabresd:
> > 
> > --- a/arch/arm/boot/dts/imx6qdl-sabresd.dtsi
> > +++ b/arch/arm/boot/dts/imx6qdl-sabresd.dtsi
> > @@ -444,6 +444,21 @@
> >                                 MX6QDL_PAD_SD3_DAT7__SD3_DATA7          0x17059
> >                         >;
> >                 };
> > +
> > +               pinctrl_usdhc4: usdhc4grp {
> > +                       fsl,pins = <
> > +                               MX6QDL_PAD_SD4_CMD__SD4_CMD             0x17059
> > +                               MX6QDL_PAD_SD4_CLK__SD4_CLK             0x10059
> > +                               MX6QDL_PAD_SD4_DAT0__SD4_DATA0          0x17059
> > +                               MX6QDL_PAD_SD4_DAT1__SD4_DATA1          0x17059
> > +                               MX6QDL_PAD_SD4_DAT2__SD4_DATA2          0x17059
> > +                               MX6QDL_PAD_SD4_DAT3__SD4_DATA3          0x17059
> > +                               MX6QDL_PAD_SD4_DAT4__SD4_DATA4          0x17059
> > +                               MX6QDL_PAD_SD4_DAT5__SD4_DATA5          0x17059
> > +                               MX6QDL_PAD_SD4_DAT6__SD4_DATA6          0x17059
> > +                               MX6QDL_PAD_SD4_DAT7__SD4_DATA7          0x17059
> [...]
> > 
> > Is there any extra patch I need to apply? I am running linux-next 20140506.
> > 
> I'm using the pad settings 0x070b1 for our i.MX6 module with eMMC.
> At least you should probably drop the HYS setting (0x10000), since
> according to my experience the SD interface works much better with
> hysteresis disabled.
> 

I'm not very sure about HYS bit, but it should not be pad setting issue.
This pad setting was tested ok with FSL internal tree.

I just tested an old Chris/mmc-next tree which is 3.14 rc2 with the top commit is b42b9b.
The eMMC works well on SabreSD boards.
But it failed and got the same issue with latest chris/mmc-next tree.
I noticed there's no changes on sdhci-esdhc-imx.c
Probably some other changes breaks this function.

Fabio,
You may bisect it yourself or i will do it later when i'm a bit free.

Shawn,
I remember this patch should have been upstream through your tree long time ago.
http://lists.infradead.org/pipermail/linux-arm-kernel/2013-October/206446.html
It seems somehow missed.

Regards
Dong Aisheng

> 
> Lothar Waßmann
> -- 
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