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 16:15:29 +0200
From:	Adrian Hunter <adrian.hunter@...el.com>
To:	Ulf Hansson <ulf.hansson@...aro.org>,
	Ludovic Desroches <ludovic.desroches@...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 17/03/16 16:00, Ulf Hansson wrote:
> 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).

It is fine by me.

Acked-by: Adrian Hunter <adrian.hunter@...el.com>

> 
> 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
>>
>