From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King - ARM Linux Subject: Re: [PATCH RFC 07/31] mmc: sdhci: push card_tasklet into threaded irq handler Date: Wed, 19 Feb 2014 09:52:12 +0000 Message-ID: <20140219095212.GT21483@n2100.arm.linux.org.uk> References: <20140218150801.GD21483@n2100.arm.linux.org.uk> <20140218175703.GJ21483@n2100.arm.linux.org.uk> <20140219094322.GR21483@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from gw-1.arm.linux.org.uk ([78.32.30.217]:42213 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752774AbaBSJwT (ORCPT ); Wed, 19 Feb 2014 04:52:19 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Viresh Kumar Cc: Pratyush Anand , spear-devel , Mohit KUMAR , "linux-arm-kernel@lists.infradead.org" , linux-mmc@vger.kernel.org, Viresh Kumar , Chris Ball On Wed, Feb 19, 2014 at 03:18:08PM +0530, Viresh Kumar wrote: > On 19 February 2014 15:13, Russell King - ARM Linux > wrote: > > On Wed, Feb 19, 2014 at 11:43:19AM +0530, Viresh Kumar wrote: > >> Adding ST people as well who have access to boards and are working on SPEAr. > >> > >> On 18 February 2014 23:27, Russell King - ARM Linux > >> wrote: > >> > 1) You're controlling the card power GPIO via the insertion/removal > >> > interrupt handler? What's wrong with using a vmmc regulator for > >> > that, which will be controlled via the MMC subsystem as required? > >> > >> Haven't explored that earlier.. Maybe its possible but no idea. > >> The requirements were like this: > >> - We may or maynot need a GPIO for controlling power > >> - If we need it, we may need to disable/enable power with card removal/ > >> insertion Or we may need to keep it enabled for ever.. > > > > So how is this any different from any other system which controls power to > > the MMC/SD socket? > > I am not claiming it to be different. I am just saying these were the > requirements > and I am not sure if they were satisfied with vmmc regulator. It might > be exactly > same in all other platforms. Are you aware that power control to the card is part of the MMC/SD/SDIO spec - and part of the protocol talking to the card? Hence why the mmc layer has support for its control built-in. If you don't want to use a regulator, then the right way to do this is to use the set_ios callback and check the power field - anything which is not MMC_POWER_OFF should result in power to the card being turned on. -- FTTC broadband for 0.8mile line: 5.8Mbps down 500kbps up. Estimation in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad. Estimate before purchase was "up to 13.2Mbit".