Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932735Ab2KNIgb (ORCPT ); Wed, 14 Nov 2012 03:36:31 -0500 Received: from mail-wg0-f44.google.com ([74.125.82.44]:36575 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751578Ab2KNIga (ORCPT ); Wed, 14 Nov 2012 03:36:30 -0500 MIME-Version: 1.0 In-Reply-To: <20121114072855.GF7407@opensource.wolfsonmicro.com> References: <25B60CDC2F704E4E9D88FFD52780CB4C060FBEA29A@SC-VEXCH1.marvell.com> <20121114072855.GF7407@opensource.wolfsonmicro.com> Date: Wed, 14 Nov 2012 16:36:28 +0800 Message-ID: Subject: Re: FW: [PATCH v2] mmc: sdhci: apply voltage range check only for non-fixed regulators From: Kevin Liu To: Mark Brown Cc: m.szyprowski@samsung.com, Chris Ball , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, kyungmin.park@samsung.com, lrg@ti.com, Philip Rakity Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1191 Lines: 27 2012/11/14 Mark Brown : > On Wed, Nov 14, 2012 at 03:11:37PM +0800, Kevin Liu wrote: > >> - ret = regulator_set_voltage(host->vqmmc, 3300000, 3300000); >> + ret = regulator_set_voltage(host->vqmmc, 2700000, 3600000); > > Should this be regulator_set_voltage_tol()? Otherwise it'd be good to > explain where the numbers come from. In SD physical layer spec 3.01 chapter 6.6.1, the threshold level for voltage range is defined as below: Vdd(min) = 2.7V while Vdd(max) = 3.6V. The card should work within the voltage range. If you are afraid the voltage value is too aggressive, maybe we can use regulator_set_voltage_tol() to set a smaller range. But which range should be reasonable? >> + ret = regulator_is_supported_voltage(host->vmmc, 1700000, >> + 1950000); > > We should really add a regulator_is_supported_voltage_tol... let me > just do that. -- 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/