Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751325AbZG3M4F (ORCPT ); Thu, 30 Jul 2009 08:56:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751082AbZG3M4E (ORCPT ); Thu, 30 Jul 2009 08:56:04 -0400 Received: from cluster-g.mailcontrol.com ([208.87.233.190]:54196 "EHLO cluster-g.mailcontrol.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750933AbZG3M4D (ORCPT ); Thu, 30 Jul 2009 08:56:03 -0400 Message-ID: <4A719811.4060904@csr.com> Date: Thu, 30 Jul 2009 13:54:41 +0100 From: David Vrabel User-Agent: Thunderbird 2.0.0.22 (X11/20090608) MIME-Version: 1.0 To: Ohad Ben-Cohen CC: Andrew Morton , Philip Langdale , Matt Fleming , ian@mnementh.co.uk, pierre@ossman.eu, linux-kernel@vger.kernel.org, linux-embedded@vger.kernel.org, nico@cam.org, nicolas.ferre@rfo.atmel.com, hskinnemoen@atmel.com, tony@atomide.com, david-b@pacbell.net, manuel.lauss@gmail.com, mirq-l@jasper.es, Adrian Hunter , Madhusudhan Subject: Re: [PATCH] sdio: add CD disable support References: <1248954848.5396.6.camel@localhost> In-Reply-To: <1248954848.5396.6.camel@localhost> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 30 Jul 2009 12:54:42.0010 (UTC) FILETIME=[E7D69BA0:01CA1114] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1900 Lines: 46 Ohad Ben-Cohen wrote: > From: Ohad Ben-Cohen > > To save power, the pull-up resistor on CD/DAT[3] (pin 1) > of the card can be disconnected. This is desired, e.g., > with embedded SDIO devices which do not rely on this pin > for card detection. Platforms may rely on the card's pull-up and not fit/configure an external one. There may need to be a way for host controller drivers to say this and prevent the disabling of the card's DAT3 pull-up. > Signed-off-by: Ohad Ben-Cohen > --- > drivers/mmc/core/sdio.c | 32 ++++++++++++++++++++++++++++++++ > include/linux/mmc/card.h | 3 ++- > 2 files changed, 34 insertions(+), 1 deletions(-) > > diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c > index fb99ccf..4c4c9a9 100644 > --- a/drivers/mmc/core/sdio.c > +++ b/drivers/mmc/core/sdio.c > @@ -165,6 +165,31 @@ static int sdio_enable_wide(struct mmc_card *card) > } > > /* > + * Disconnect the pull-up resistor on CD/DAT[3] if requested by the card. > + * If card detection is not needed, this can save some power. > + */ The first sentence of this comment doesn't make sense. The decision to disable the pull-up is for the controller driver to make, not that card. David -- David Vrabel, Senior Software Engineer, Drivers CSR, Churchill House, Cambridge Business Park, Tel: +44 (0)1223 692562 Cowley Road, Cambridge, CB4 0WZ http://www.csr.com/ 'member of the CSR plc group of companies. CSR plc registered in England and Wales, registered number 4187346, registered office Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, United Kingdom' -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/