linux-kernel - Re: [PATCH] mmc: sdhci-of-at91: fix cd-gpios for SAMA5D2

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Date:   Mon, 23 Mar 2020 20:23:51 +0000
From:   <Ludovic.Desroches@...rochip.com>
To:     <mirq-linux@...e.qmqm.pl>, <ulf.hansson@...aro.org>,
        <adrian.hunter@...el.com>, <Nicolas.Ferre@...rochip.com>,
        <alexandre.belloni@...tlin.com>
CC:     <linux-mmc@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mmc: sdhci-of-at91: fix cd-gpios for SAMA5D2

Hi,


On 3/15/2020 5:44 PM, Michał Mirosław wrote
> SAMA5D2x doesn't drive CMD line if GPIO is used as CD line (at least
> SAMA5D27 doesn't). Fix this by forcing card-detect in the module
> if module-controlled CD is not used.
>
> Fixed commit addresses the problem only for non-removable cards. This
> amends it to also cover gpio-cd case.
>
> Cc: stable@...r.kernel.org
> Fixes: 7a1e3f143176 ("mmc: sdhci-of-at91: force card detect value for non removable devices")
> Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>

Even if it's too late, I agree with this patch. Thanks, I didn't expect 
someone will use a GPIO CD instead of the

one of the controller so this case was missing.

In fact, the whole SAMA5D2 family is concerned depending on the revision 
of the SoC. From the top of my head,

for rev A, if the pin is muxed to another function than the SDMMC 
controller, the default value is card present.

For rev B and later, the default value is no card present, that's why 
the CMD line is not driven.

Regards

Ludovic


> ---
>   drivers/mmc/host/sdhci-of-at91.c | 8 ++++++--
>   1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
> index d90f4ed18283..8f8da2fe48a9 100644
> --- a/drivers/mmc/host/sdhci-of-at91.c
> +++ b/drivers/mmc/host/sdhci-of-at91.c
> @@ -185,7 +185,8 @@ static void sdhci_at91_reset(struct sdhci_host *host, u8 mask)
>
>          sdhci_reset(host, mask);
>
> -       if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
> +       if ((host->mmc->caps & MMC_CAP_NONREMOVABLE)
> +           || mmc_gpio_get_cd(host->mmc) >= 0)
>                  sdhci_at91_set_force_card_detect(host);
>
>          if (priv->cal_always_on && (mask & SDHCI_RESET_ALL))
> @@ -487,8 +488,11 @@ static int sdhci_at91_probe(struct platform_device *pdev)
>           * detection procedure using the SDMCC_CD signal is bypassed.
>           * This bit is reset when a software reset for all command is performed
>           * so we need to implement our own reset function to set back this bit.
> +        *
> +        * WA: SAMA5D2 doesn't drive CMD if using CD GPIO line.
>           */
> -       if (host->mmc->caps & MMC_CAP_NONREMOVABLE)
> +       if ((host->mmc->caps & MMC_CAP_NONREMOVABLE)
> +           || mmc_gpio_get_cd(host->mmc) >= 0)
>                  sdhci_at91_set_force_card_detect(host);
>
>          pm_runtime_put_autosuspend(&pdev->dev);
> --
> 2.20.1
>