Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753750AbbGFHc3 (ORCPT ); Mon, 6 Jul 2015 03:32:29 -0400 Received: from eusmtp01.atmel.com ([212.144.249.242]:5971 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753683AbbGFHcW (ORCPT ); Mon, 6 Jul 2015 03:32:22 -0400 Date: Mon, 6 Jul 2015 09:33:04 +0200 From: Ludovic Desroches To: Arnd Bergmann CC: Ludovic Desroches , , , , , , Subject: Re: [PATCH 2/3] mmc: sdhci-of-at91: introduce driver for the Atmel SDMMC Message-ID: <20150706073304.GA24167@odux.rfo.atmel.com> Mail-Followup-To: Arnd Bergmann , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, ulf.hansson@linaro.org, nicolas.ferre@atmel.com, alexandre.belloni@free-electrons.com References: <1435933037-12889-1-git-send-email-ludovic.desroches@atmel.com> <1435933037-12889-3-git-send-email-ludovic.desroches@atmel.com> <8304633.2ajieYmcMU@wuerfel> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <8304633.2ajieYmcMU@wuerfel> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3679 Lines: 94 On Sat, Jul 04, 2015 at 10:06:49PM +0200, Arnd Bergmann wrote: > On Friday 03 July 2015 16:17:16 Ludovic Desroches wrote: > > Introduce driver for he Atmel SDMMC available on sama5d2. It is a sdhci > > compliant controller. > > > > Signed-off-by: Ludovic Desroches > > --- > > .../devicetree/bindings/mmc/sdhci-atmel.txt | 21 +++ > > drivers/mmc/host/Kconfig | 8 + > > drivers/mmc/host/Makefile | 1 + > > drivers/mmc/host/sdhci-of-at91.c | 188 +++++++++++++++++++++ > > 4 files changed, 218 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/mmc/sdhci-atmel.txt > > create mode 100644 drivers/mmc/host/sdhci-of-at91.c > > > > diff --git a/Documentation/devicetree/bindings/mmc/sdhci-atmel.txt b/Documentation/devicetree/bindings/mmc/sdhci-atmel.txt > > new file mode 100644 > > index 0000000..1b662d7 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/mmc/sdhci-atmel.txt > > @@ -0,0 +1,21 @@ > > +* Atmel SDHCI controller > > + > > +This file documents the differences between the core properties in > > +Documentation/devicetree/bindings/mmc/mmc.txt and the properties used by the > > +sdhci-of-at91 driver. > > + > > +Required properties: > > +- compatible: Must be "atmel,sama5d2-sdhci". > > +- clocks: Phandlers to the clocks. > > +- clock-names: Must be "hclock", "multclk", "baseclk"; > > + > > Are you sure that these are all new clocks that are unrelated to the "core", > "mmc", and "iface" clocks that are used in other drivers? > Maybe hclock could be considered as the core and interface clock. The mmc clock will be baseclk or multclk. I think other devices manage the multclk internally. Here we have to provide both clocks. Internally, we only choose which clock to use and add a divider if necessary. > > + > > + priv->mainck = devm_clk_get(&pdev->dev, "baseclk"); > > + if (IS_ERR(priv->mainck)) { > > + dev_err(&pdev->dev, "failed to get baseclk\n"); > > + return PTR_ERR(priv->mainck); > > + } > > + > > + priv->hclock = devm_clk_get(&pdev->dev, "hclock"); > > + if (IS_ERR(priv->hclock)) { > > + dev_err(&pdev->dev, "failed to get hclock\n"); > > + return PTR_ERR(priv->hclock); > > + } > > + > > + priv->gck = devm_clk_get(&pdev->dev, "multclk"); > > + if (IS_ERR(priv->gck)) { > > + dev_err(&pdev->dev, "failed to get multclk\n"); > > + return PTR_ERR(priv->gck); > > + } > > + > > + host = sdhci_pltfm_init(pdev, soc_data, 0); > > + if (IS_ERR(host)) > > + return PTR_ERR(host); > > + > > + /* > > + * The mult clock is provided by as a generated clock by the PMC > > + * controller. In order to set the rate of gck, we have to get the > > + * base clock rate and the clock mult from capabilities. > > + */ > > + clk_prepare_enable(priv->hclock); > > + caps0 = readl(host->ioaddr + SDHCI_CAPABILITIES); > > + caps1 = readl(host->ioaddr + SDHCI_CAPABILITIES_1); > > + clk_base = (caps0 & SDHCI_CLOCK_V3_BASE_MASK) >> SDHCI_CLOCK_BASE_SHIFT; > > + clk_mul = (caps1 & SDHCI_CLOCK_MUL_MASK) >> SDHCI_CLOCK_MUL_SHIFT; > > + gck_rate = clk_base * 1000000 * (clk_mul + 1); > > + ret = clk_set_rate(priv->gck, gck_rate); > > + if (ret < 0) { > > + dev_err(&pdev->dev, "failed to set gck"); > > + goto hclock_disable_unprepare; > > + return -EINVAL; > > + } > > Could this be shared with other drivers? No, it's risk-free to do this. > > Arnd -- 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/