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

Ulf Hansson
2015-05-18T07:58:41Z

On 17 May 2015 at 10:36, Joakim Tjernlund <joakim.tjernlund@transmode.se> wrote:
> 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?

Sorry, I don't have enough knowledge about sdhci to give you good answer.

>
> Didn't this patch work for you either?

I have dropped the "sdhci-of-edsdhc: Support 8-bit..." from my next
branch for now.

A "Tested-by" confirmation of a new version of $subject patch, would
help me to know when it can go in.

Kind regards
Uffe