Re: [PATCH 1/4] mmc: sdhci: Add delay after power off

[Adrian Hunter <adrian.hunter@intel.com>]

On 2/12/19 4:41 pm, Jun Nie wrote:
> Add delay after power off to ensure that full power cycle is
> successful. Otherwise, some controllers, at lease for Hisilicon
> eMMC controller, may not be unstable sometimes for full power
> cycle operation.
> 
> Signed-off-by: Jun Nie <jun.nie@linaro.org>
> ---
>  drivers/mmc/host/sdhci.c | 7 +++++++
>  drivers/mmc/host/sdhci.h | 2 ++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 3140fe2e5dba..a654f0aeb438 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1761,6 +1761,13 @@ void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
>  		sdhci_writeb(host, 0, SDHCI_POWER_CONTROL);
>  		if (host->quirks2 & SDHCI_QUIRK2_CARD_ON_NEEDS_BUS_ON)
>  			sdhci_runtime_pm_bus_off(host);
> +
> +		/*
> +		 * Some controllers need an extra 100ms delay to secure
> +		 * full power cycle is successful.
> +		 */
> +		if (host->quirks2 & SDHCI_QUIRK2_DELAY_AFTER_POWER_OFF)
> +			msleep(100);

Please use the ->set_power() callback and do this in your own driver.

>  	} else {
>  		/*
>  		 * Spec says that we should clear the power reg before setting
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 0ed3e0eaef5f..0e6f97eaa796 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -482,6 +482,8 @@ struct sdhci_host {
>   * block count.
>   */
>  #define SDHCI_QUIRK2_USE_32BIT_BLK_CNT			(1<<18)
> +/* Controllers need an extra 100ms delay to make sure power off completely */
> +#define SDHCI_QUIRK2_DELAY_AFTER_POWER_OFF		(1<<19)
>  
>  	int irq;		/* Device IRQ */
>  	void __iomem *ioaddr;	/* Mapped address */
>