Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754772AbaDOSZI (ORCPT ); Tue, 15 Apr 2014 14:25:08 -0400 Received: from avon.wwwdotorg.org ([70.85.31.133]:50937 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752340AbaDOSZE (ORCPT ); Tue, 15 Apr 2014 14:25:04 -0400 Message-ID: <534D797D.7030201@wwwdotorg.org> Date: Tue, 15 Apr 2014 12:25:01 -0600 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Andrew Bresticker , Thierry Reding , Chris Ball , Ulf Hansson CC: linux-mmc@vger.kernel.org, linux-tegra@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] mmc: tegra: fix reporting of base clock frequency References: <1397526163-20126-1-git-send-email-abrestic@chromium.org> <1397526163-20126-3-git-send-email-abrestic@chromium.org> In-Reply-To: <1397526163-20126-3-git-send-email-abrestic@chromium.org> X-Enigmail-Version: 1.5.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/14/2014 07:42 PM, Andrew Bresticker wrote: > Tegra SDHCI controllers, by default, report a base clock frequency > of 208Mhz in SDHCI_CAPABILTIES which may or may not be equal to the > actual base clock frequency. Some explanation of why this "may or may not be equal to the actual base clock frequency" would be nice. Presumably, it's because the clock frequency is supplied by the clock controller module, and configuring that happens externally to the SD controller, so the SD HW has no knowledge of the actual frequency, and hence simply reports a hard-coded maximum possible clock frequency? > While this can be overridden by setting > BASE_CLK_FREQ in VENDOR_CLOCK_CTRL on Tegra30 and later SoCs, just > set SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN and supply a get_max_clock() > callback to get the actual rate of the base clock. It's not clear to me from the function name that sdhci_pltfm_clk_get_max_clock() simply calls clk_get() on the actual clock. It might be nice to mention that in the commit description. -- 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/