public inbox for linux-mmc@vger.kernel.org
 help / color / mirror / Atom feed
From: Joakim Tjernlund <joakim.tjernlund@transmode.se>
To: "haokexin@gmail.com" <haokexin@gmail.com>
Cc: "ulf.hansson@linaro.org" <ulf.hansson@linaro.org>,
	"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>
Subject: Re: [PATCH] Revert "sdhci-of-esdhc: Support 8BIT bus width."
Date: Sun, 17 May 2015 08:36:07 +0000	[thread overview]
Message-ID: <1431851766.6782.7.camel@transmode.se> (raw)
In-Reply-To: <20150517050602.GB23513@pek-khao-d1.corp.ad.wrs.com>

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

  reply	other threads:[~2015-05-17  8:36 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-15  6:29 [PATCH] Revert "sdhci-of-esdhc: Support 8BIT bus width." Kevin Hao
2015-05-15  7:02 ` Joakim Tjernlund
2015-05-15  7:24   ` Joakim Tjernlund
2015-05-15  7:42     ` Kevin Hao
2015-05-15  8:00       ` Joakim Tjernlund
2015-05-15  8:20       ` Joakim Tjernlund
2015-05-15 12:40       ` Joakim Tjernlund
2015-05-17  5:06         ` Kevin Hao
2015-05-17  8:36           ` Joakim Tjernlund [this message]
2015-05-18  7:58             ` Ulf Hansson
2015-05-19  9:20             ` Kevin Hao
2015-05-20 14:54               ` Joakim Tjernlund
2015-05-21  1:07                 ` Kevin Hao
2015-05-21  9:24                   ` Joakim Tjernlund
2015-05-21 10:56                     ` Kevin Hao
2015-05-21 11:45                       ` Joakim Tjernlund
2015-05-22 13:46                         ` Ulf Hansson
2015-05-15  7:36   ` Kevin Hao
2015-05-15  7:49     ` Joakim Tjernlund
2015-05-17  5:04       ` Kevin Hao

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1431851766.6782.7.camel@transmode.se \
    --to=joakim.tjernlund@transmode.se \
    --cc=haokexin@gmail.com \
    --cc=linux-mmc@vger.kernel.org \
    --cc=ulf.hansson@linaro.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox