linux-kernel - Re: [PATCH v2] mmc: sdhci-of-at91: fix wake-up issue when using runtime pm

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Date:	Thu, 17 Mar 2016 15:00:57 +0100
From:	Ulf Hansson <ulf.hansson@...aro.org>
To:	Ludovic Desroches <ludovic.desroches@...el.com>,
	Adrian Hunter <adrian.hunter@...el.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-mmc <linux-mmc@...r.kernel.org>,
	Nicolas Ferre <nicolas.ferre@...el.com>
Subject: Re: [PATCH v2] mmc: sdhci-of-at91: fix wake-up issue when using
 runtime pm

On 17 March 2016 at 14:54, Ludovic Desroches
<ludovic.desroches@...el.com> wrote:
> It is impossible to wake-up on card detect event because when sdhci
> controller is runtime suspended, it is assumed that all clocks are
> disabled so we can't get irqs.
> If the device is removable and there is no gpio to manage the card
> detection then polling is used. It doesn't mean card detection is broken.
> It is curently we only way to wake-up on card event if using runtime pm.
>
> Signed-off-by: Ludovic Desroches <ludovic.desroches@...el.com>

I have applied this for next (4.6) so to get it tested in linux-next.

Adrian, please tell me if you have any objections then I will drop it
(or add your ack).

Thanks and kind regards
Uffe

> ---
>
> Changes:
> - v2:
>   - remove SDHCI_QUIRK_BROKEN_CARD_DETECTION quirk if set by the broken-cd
>   property.
>
>  drivers/mmc/host/sdhci-of-at91.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
> index 35c02fc..2703aa9 100644
> --- a/drivers/mmc/host/sdhci-of-at91.c
> +++ b/drivers/mmc/host/sdhci-of-at91.c
> @@ -18,6 +18,7 @@
>  #include <linux/err.h>
>  #include <linux/io.h>
>  #include <linux/mmc/host.h>
> +#include <linux/mmc/slot-gpio.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_device.h>
> @@ -204,6 +205,25 @@ static int sdhci_at91_probe(struct platform_device *pdev)
>         if (ret)
>                 goto pm_runtime_disable;
>
> +       /*
> +        * When calling sdhci_runtime_suspend_host(), the sdhci layer makes
> +        * the assumption that all the clocks of the controller are disabled.
> +        * It means we can't get irq from it when it is runtime suspended.
> +        * For that reason, it is not planned to wake-up on a card detect irq
> +        * from the controller.
> +        * If we want to use runtime PM and to be able to wake-up on card
> +        * insertion, we have to use a GPIO for the card detection or we can
> +        * use polling. Be aware that using polling will resume/suspend the
> +        * controller between each attempt.
> +        * Disable SDHCI_QUIRK_BROKEN_CARD_DETECTION to be sure nobody tries
> +        * to enable polling via device tree with broken-cd property.
> +        */
> +       if (!(host->mmc->caps & MMC_CAP_NONREMOVABLE) &&
> +           IS_ERR_VALUE(mmc_gpio_get_cd(host->mmc))) {
> +               host->mmc->caps |= MMC_CAP_NEEDS_POLL;
> +               host->quirks &= ~SDHCI_QUIRK_BROKEN_CARD_DETECTION;
> +       }
> +
>         pm_runtime_put_autosuspend(&pdev->dev);
>
>         return 0;
> --
> 2.5.0
>