Re: [PATCH] Revert "sdhci-of-esdhc: Support 8BIT bus width."

Joakim Tjernlund
2015-05-17T08:36:12Z

On Sun, 2015-05-17 at 13:06 +0800, Kevin Hao wrote:
> >
> > How about this one:
> >
> > From af6b18c056b6064424bd2ab1f9989bbadae5e701 Mon Sep 17 00:00:00 2001
> > From: Joakim Tjernlund <joakim.tjernlund@transmode.se>
> > Date: Mon, 20 Apr 2015 22:36:55 +0200
> > Subject: [PATCHv3] sdhci-of-esdhc: Support 8BIT bus width.
> >
> > esdhc_readb()/esdhc_writeb() did not adjust for 8BIT.
>
> Do we really need this for the 8bit bus support? There is already a specific
> API for setting the bus width, this change seems unnecessary to me. That is
> also why I choose to revert that patch. Did I miss something?

We do, the bus API really only works well when the bus bits are in another
register but the HOST_CONTROL register.
The only reason 4BIT works is because its bit placement is where
SDHCI expects it to be. 8BIT is not, so unless readb/writeb funktions compensate
for that they will overwrite what the bus API set earlier.

Atleast this is my understanding, Ulf?

Didn't this patch work for you either?

Jocke