From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH] mmc: sdhci-of-at91: force card detect value for non removable devices Date: Mon, 31 Jul 2017 09:33:42 +0300 Message-ID: <0043eaf4-7c3b-429f-e508-a273f20960f0@intel.com> References: <20170726140246.4775-1-ludovic.desroches@microchip.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com ([134.134.136.20]:52593 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751688AbdGaGkD (ORCPT ); Mon, 31 Jul 2017 02:40:03 -0400 In-Reply-To: <20170726140246.4775-1-ludovic.desroches@microchip.com> Content-Language: en-US Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Ludovic Desroches , linux-mmc@vger.kernel.org Cc: ulf.hansson@linaro.org, linux-kernel@vger.kernel.org, alexandre.belloni@free-electrons.com, nicolas.ferre@microchip.com On 26/07/17 17:02, Ludovic Desroches wrote: > When the device is non removable, the card detect signal is often use use -> used > for another purpose i.e. muxed to another SoC peripheral or used as a > GPIO. It could lead to wrong behaviors depending the defaut value of defaut -> default > this signal if not muxed to the SDHCI controller. > > Fixes: bb5f8ea4d514 ("mmc: sdhci-of-at91: introduce driver for the Atmel SDMMC") > Signed-off-by: Ludovic Desroches Apart from spelling Acked-by: Adrian Hunter > --- > drivers/mmc/host/sdhci-of-at91.c | 36 +++++++++++++++++++++++++++++++++++- > 1 file changed, 35 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c > index 88e9b5f35a62..6a389f35396e 100644 > --- a/drivers/mmc/host/sdhci-of-at91.c > +++ b/drivers/mmc/host/sdhci-of-at91.c > @@ -31,6 +31,7 @@ > > #define SDMMC_MC1R 0x204 > #define SDMMC_MC1R_DDR BIT(3) > +#define SDMMC_MC1R_FCD BIT(7) > #define SDMMC_CACR 0x230 > #define SDMMC_CACR_CAPWREN BIT(0) > #define SDMMC_CACR_KEY (0x46 << 8) > @@ -44,6 +45,15 @@ struct sdhci_at91_priv { > bool restore_needed; > }; > > +static void sdhci_at91_set_force_card_detect(struct sdhci_host *host) > +{ > + u8 mc1r; > + > + mc1r = readb(host->ioaddr + SDMMC_MC1R); > + mc1r |= SDMMC_MC1R_FCD; > + writeb(mc1r, host->ioaddr + SDMMC_MC1R); > +} > + > static void sdhci_at91_set_clock(struct sdhci_host *host, unsigned int clock) > { > u16 clk; > @@ -111,10 +121,18 @@ void sdhci_at91_set_uhs_signaling(struct sdhci_host *host, unsigned int timing) > sdhci_set_uhs_signaling(host, timing); > } > > +static void sdhci_at91_reset(struct sdhci_host *host, u8 mask) > +{ > + sdhci_reset(host, mask); > + > + if (host->mmc->caps & MMC_CAP_NONREMOVABLE) > + sdhci_at91_set_force_card_detect(host); > +} > + > static const struct sdhci_ops sdhci_at91_sama5d2_ops = { > .set_clock = sdhci_at91_set_clock, > .set_bus_width = sdhci_set_bus_width, > - .reset = sdhci_reset, > + .reset = sdhci_at91_reset, > .set_uhs_signaling = sdhci_at91_set_uhs_signaling, > .set_power = sdhci_at91_set_power, > }; > @@ -369,6 +387,22 @@ static int sdhci_at91_probe(struct platform_device *pdev) > host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION; > } > > + /* > + * If the device attached to the MMC bus is not removable, it is safer > + * to set the Force Card Detect bit. People often don't connect the > + * card detect signal and use this pin for another purpose. If the card > + * detect pin is not muxed to SDHCI controller, a default value is > + * used. This value can be different from a SoC revision to another > + * one. Problems come when this default value is not card present. To > + * avoid this case, if the device is non removable then the card > + * detection procedure using the SDMCC_CD signal is bypassed. > + * This bit is resetted when a software reset for all command is resetted -> reset > + * performed so we need to implement our own reset function to set back > + * this bit. > + */ > + if (host->mmc->caps & MMC_CAP_NONREMOVABLE) > + sdhci_at91_set_force_card_detect(host); > + > pm_runtime_put_autosuspend(&pdev->dev); > > return 0; >