From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [203.10.76.45]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mx.ozlabs.org", Issuer "CA Cert Signing Authority" (verified OK)) by bilbo.ozlabs.org (Postfix) with ESMTPS id 11BF6B7230 for ; Thu, 18 Jun 2009 06:14:09 +1000 (EST) Date: Thu, 18 Jun 2009 00:13:29 +0400 From: Anton Vorontsov To: Grant Likely Subject: Re: [PATCH] sdhci: Add support for hosts that are only capable of 1-bit transfers Message-ID: <20090617201329.GA9149@oksana.dev.rtsoft.ru> References: <20090611201545.GA15942@oksana.dev.rtsoft.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 In-Reply-To: Cc: linuxppc-dev@ozlabs.org, Pierre Ossman , devicetree-discuss@ozlabs.org, sdhci-devel@lists.ossman.eu Reply-To: avorontsov@ru.mvista.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Sat, Jun 13, 2009 at 09:40:02AM -0600, Grant Likely wrote: > On Thu, Jun 11, 2009 at 2:15 PM, Anton > Vorontsov wrote: > > Some hosts (hardware configurations, or particular SD/MMC slots) may > > not support 4-bit bus. For example, on MPC8569E-MDS boards we can > > switch between serial (1-bit only) and nibble (4-bit) modes, thought > > we have to disable more peripherals to work in 4-bit mode. > > > > Along with some small core changes, this patch modifies sdhci-of > > driver, so that now it looks for "mode" property in the device-tree. > > > > Signed-off-by: Anton Vorontsov > > --- > > > > Pierre, I'm not sure if a quirk would be appropriate here. If so, > > I can redo the patch with FORCE_1_BIT_DATA quirk. > > > > Thanks, > > > >  Documentation/powerpc/dts-bindings/fsl/esdhc.txt |    2 ++ > >  drivers/mmc/host/sdhci-of.c                      |    7 +++++++ > >  drivers/mmc/host/sdhci-pci.c                     |    1 + > >  drivers/mmc/host/sdhci.c                         |    2 +- > >  4 files changed, 11 insertions(+), 1 deletions(-) > > > > diff --git a/Documentation/powerpc/dts-bindings/fsl/esdhc.txt b/Documentation/powerpc/dts-bindings/fsl/esdhc.txt > > index 5093ddf..298b865 100644 > > --- a/Documentation/powerpc/dts-bindings/fsl/esdhc.txt > > +++ b/Documentation/powerpc/dts-bindings/fsl/esdhc.txt > > @@ -10,6 +10,8 @@ Required properties: > >   - interrupts : should contain eSDHC interrupt. > >   - interrupt-parent : interrupt source phandle. > >   - clock-frequency : specifies eSDHC base clock frequency. > > +  - mode : specifies eSDHC mode, valid values are: "1-bit" and "4-bit". > > +    If mode is unspecified, then 4-bit mode is assumed. > > In light of Pierre's comment that 4-bit is mandatory and this is a > deviation, perhaps it would be better to define an empty property to > indicate that only 1-bit transfers work. Maybe something along the > lines of "sdhc-1-bit-only"? Yeah, since it turned up to be a quirk, we'd better use a named property. (I think that by convention we should use commas for controller-specific properties, i.e. "sdhci,property".) Thanks! -- Anton Vorontsov email: cbouatmailru@gmail.com irc://irc.freenode.net/bd2