Re: [RFC PATCH 4/4] mmc: sdhci-of-arasan: overwrite enhanced strobe callback

[Shawn Lin]

On 2016/3/3 19:02, Michal Simek wrote:
> On 3.3.2016 03:36, Shawn Lin wrote:
> > Currently sdhci-arasan 5.1 can support enhanced strobe function,
> > but considering the potential requirement in the future for other
> > version IP, we don't limit it just for "arasan,sdhci-5.1". Add
> > cap-enhanced-strobe in DT to enable the function if we'r sure our
> > controller can support it.
> >
> > Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> > ---
> >
> >   drivers/mmc/host/sdhci-of-arasan.c | 20 ++++++++++++++++++++
> >   1 file changed, 20 insertions(+)
> >
> > diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
> > index 1e4b5e0..31f3494 100644
> > --- a/drivers/mmc/host/sdhci-of-arasan.c
> > +++ b/drivers/mmc/host/sdhci-of-arasan.c
> > @@ -24,7 +24,9 @@
> >   #include "sdhci-pltfm.h"
> >
> >   #define SDHCI_ARASAN_CLK_CTRL_OFFSET	0x2c
> > +#define SDHCI_ARASAN_VENDOR_REGISTER	0x78
>
> I was checking our register map and we even don't have this register
> listed as reserved.
> It looks like that this will be related to certain SoC and different SoC
> can use it different location.
> That's why I think this feature and setup should be related to certain
> SoC specific compatible string.

Hi Michal,

I think that is IP version specific because it's inside controller's
databook. But I only have a datasheet released by arasan for 5.1 
controller, so I didn't know if your databook has this register. And
I can't find sdhci spec has a reg to enable this feature either. Looks
strange, but maybe you are right: it also related to certain Soc for
other sdhci variant drivers. But for sdhci-of-arsan, it more likes to
use this register from now on for the future IP version to enable this
feature inside the controller register-range.

Thanks for checking that. Now, I'm more sure about that we should limit
it for 5.1 currently by checking the compatible string.

I expect more comments from ulf and adrian about the other part of code
until I respin the next version.

> Thanks,
> Michal


--
Best Regards
Shawn Lin