archive mirror
 help / color / mirror / Atom feed
From: "S, Venkatraman" <>
To: "Hebbar, Gururaja" <>
Subject: Re: [PATCH] mmc: omap_hsmmc: Enable HSPE bit for high speed cards
Date: Wed, 12 Sep 2012 14:19:51 +0530	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Tue, Sep 4, 2012 at 6:39 PM, Hebbar, Gururaja <> wrote:
> HSMMC IP on AM33xx need a special setting to handle High-speed cards.
> Other platforms like TI81xx, OMAP4 may need this as-well. This depends
> on the HSMMC IP timing closure done for the high speed cards.
> From AM335x TRM (SPRUH73F - 18.3.12 Output Signals Generation)
> The MMC/SD/SDIO output signals can be driven on either falling edge or
> rising edge depending on the SD_HCTL[2] HSPE bit. This feature allows
> to reach better timing performance, and thus to increase data transfer
> frequency.
> There are few pre-requisites for enabling the HSPE bit
> - Controller should support High-Speed-Enable Bit and
> - Controller should not be using DDR Mode and
> - Controller should advertise that it supports High Speed in
>   capabilities register and
> - MMC/SD clock coming out of controller > 25MHz

The patch is well written. But then, I don't see a need for a DT
binding for this feature.
By definition, HS implies 25MHz or above, so that check seems to be
redundant as well.
Meanwhile, I'll check with HSPE enabled on OMAP.


  parent reply	other threads:[~2012-09-12  8:50 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-04 13:09 [PATCH] mmc: omap_hsmmc: Enable HSPE bit for high speed cards Hebbar, Gururaja
2012-09-12  7:48 ` Hebbar, Gururaja
2012-09-12  8:49 ` S, Venkatraman [this message]
2012-09-12 12:02   ` Hebbar, Gururaja
2012-09-26 11:37   ` Hebbar, Gururaja
2012-09-27 11:01     ` Koen Kooi
2012-09-27 11:35       ` Hebbar, Gururaja
2012-09-12  9:21 ` T Krishnamoorthy, Balaji
2012-09-12 11:41   ` Hebbar, Gururaja

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:

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

  git send-email \ \ \ \ \ \ \ \ \ \ \ \

* 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;
as well as URLs for NNTP newsgroup(s).