Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933525AbZFMBIO (ORCPT ); Fri, 12 Jun 2009 21:08:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758898AbZFMBH7 (ORCPT ); Fri, 12 Jun 2009 21:07:59 -0400 Received: from mail-ew0-f210.google.com ([209.85.219.210]:41947 "EHLO mail-ew0-f210.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753263AbZFMBH7 convert rfc822-to-8bit (ORCPT ); Fri, 12 Jun 2009 21:07:59 -0400 MIME-Version: 1.0 In-Reply-To: References: Date: Fri, 12 Jun 2009 18:08:00 -0700 X-Google-Sender-Auth: f8581934d70f56d4 Message-ID: Subject: Re: [PATCH 4/6] Unified AVR32/AT91 MCI Driver From: Rob Emanuele To: Haavard Skinnemoen Cc: Andrew Victor , Nicolas Ferre , linux-arm-kernel@lists.arm.linux.org.uk, linux-kernel@vger.kernel.org, drzeus-mmc@drzeus.cx Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2942 Lines: 86 Please disregard this patch/message as the subject is incorrect. Thank you, Rob Emanuele On Fri, Jun 12, 2009 at 6:02 PM, Rob Emanuele wrote: > This patch adds the compile time configuration option for the > atmel-mci driver to cap the MCI CLKDIV register value to a minimum > value. > > This is useful for debugging and for boards that have a long mci clock line. > > Please read the whole set, try it out, and comment. > > Thank you, > > Rob Emanuele > > --- > ?drivers/mmc/host/Kconfig ? ? | ? 14 ++++++++++++++ > ?drivers/mmc/host/atmel-mci.c | ? 10 ++++++++++ > ?2 files changed, 24 insertions(+), 0 deletions(-) > > diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig > index 9e24029..9f797b2 100644 > --- a/drivers/mmc/host/Kconfig > +++ b/drivers/mmc/host/Kconfig > @@ -150,6 +150,20 @@ config MMC_ATMELMCI > > ?endchoice > > +config MMC_ATMELMCI_CLKDIV_CAP > + ? ? ? int "Cap the CLKDIV to keep the controller from going too fast." > + ? ? ? depends on MMC_ATMELMCI > + ? ? ? default 0 > + ? ? ? range 0 255 > + ? ? ? help > + ? ? ? ? This is the lowest value the clock divisor for the MMC > + ? ? ? ? controller can be. ?Value is between 0 and 255. > + ? ? ? ? MCI_CK = MCK/(2*(CLKDIV+1)) > + ? ? ? ? Raising this value may improve your controller's reliability > + ? ? ? ? at the cost of speed. > + > + ? ? ? ? If unsure, leave at 0. > + > ?config MMC_ATMELMCI_ALWAYS_RESET > ? ? ? ?bool "Reset before every request. ?Sometimes needed for buggy chips." > ? ? ? ?depends on MMC_ATMELMCI > diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c > index b133baa..1c1a4b3 100644 > --- a/drivers/mmc/host/atmel-mci.c > +++ b/drivers/mmc/host/atmel-mci.c > @@ -74,6 +74,10 @@ struct atmel_mci_dma { > ?#define MMC_ALWAYS_RESET 0 > ?#endif > > +#ifndef CONFIG_MMC_ATMELMCI_CLKDIV_CAP > +#define CONFIG_MMC_ATMELMCI_CLKDIV_CAP 0 > +#endif > + > ?/** > ?* struct atmel_mci - MMC controller state shared between all slots > ?* @lock: Spinlock protecting the queue and associated data. > @@ -876,6 +880,12 @@ static void atmci_set_ios(struct mmc_host *mmc, > struct mmc_ios *ios) > ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?clock_min, host->bus_hz / (2 * 256)); > ? ? ? ? ? ? ? ? ? ? ? ?clkdiv = 255; > ? ? ? ? ? ? ? ?} > + ? ? ? ? ? ? ? if (clkdiv < CONFIG_MMC_ATMELMCI_CLKDIV_CAP) { > + ? ? ? ? ? ? ? ? ? ? ? dev_warn(&mmc->class_dev, > + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? "clkdiv %u too fast; capped using %u\n", > + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?clkdiv, CONFIG_MMC_ATMELMCI_CLKDIV_CAP); > + ? ? ? ? ? ? ? ? ? ? ? clkdiv = CONFIG_MMC_ATMELMCI_CLKDIV_CAP; > + ? ? ? ? ? ? ? } > > ? ? ? ? ? ? ? ?host->mode_reg = MCI_MR_CLKDIV(clkdiv); > > -- > 1.6.0.4 > -- 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/