Re: [PATCH] mmc: sdhci-of-at91: fix wakeup issue when using runtime pm
From: Ulf Hansson
Date: Wed Mar 16 2016 - 07:04:57 EST
On 10 March 2016 at 11:30, Ludovic Desroches
> It was impossible to wake-up on card detect event because when sdhci
> controller is runtime suspend, it is assumed that all the 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 card detection polling is used.
> Signed-off-by: Ludovic Desroches <ludovic.desroches@xxxxxxxxx>
> Hi Ulf, Adrian,
> Following the discussion, I need to fix my issue. I think we could both agree
> on this patch that I see more as temporary workaround.
> I will try to change the muxing of the card detect pio in order to no more
> use the sdhci controller to manage it but a gpio. If it do not work then
> I may send another patch in the spirit of the previous one (keeping one clock
> enabled and not calling sdhci_runtime_suspend_host()).
> drivers/mmc/host/sdhci-of-at91.c | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
> diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c
> index 35c02fc..dac8508 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 +205,21 @@ 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 for the card detection. Be aware that using polling
> + * will resume/suspend the controller between each attempt.
> + */
> + if (!(host->mmc->caps & MMC_CAP_NONREMOVABLE) &&
> + IS_ERR_VALUE(mmc_gpio_get_cd(host->mmc)))
> + host->mmc->caps |= MMC_CAP_NEEDS_POLL;
Perhaps also clearing SDHCI_QUIRK_BROKEN_CARD_DETECTION, as this
doesn't play well if this is set via parsing the DTS.
> return 0;
Otherwise this looks okay to me.