Re: [PATCH v3 3/7] mmc: sdhci-esdhc-imx: restore pinctrl before restoring ios timing on resume

[Bough Chen]

On Mon, Jun 29, 2026 at 05:19:50PM +0800, ziniu.wang_1@xxxxxxxxxxx wrote:
> From: Luke Wang <ziniu.wang_1@xxxxxxx>
> 
> SDIO devices such as WiFi may keep power during suspend, so the MMC
> core skips full card re-initialization on resume and directly restores
> the host controller's ios timing to match the card. For DDR mode,
> pm_runtime_force_resume() sets DDR_EN before the pin configuration is
> restored from sleep state.
> 
> This is related to the SoC IP integration: switching pinctrl setting
> (changing alt from GPIO to USDHC) impacts the internal loopback path.
> If pinctrl configures the pad to GPIO function, once DDR_EN is set, the
> DLL delay will be fixed based on the GPIO function loopback path. When
> the pinctrl is later changed to USDHC function, the internal loopback
> path changes, making the original fixed sample point no longer suitable
> for the current loopback path. This causes persistent read CRC errors on
> subsequent data transfers.
> 
> SD/eMMC running in DDR mode are unaffected as they are fully
> re-initialized from legacy timing after resume.
> 
> Fix this by restoring the pinctrl state based on current timing mode
> using esdhc_change_pinstate() before pm_runtime_force_resume(). This
> ensures the correct pin configuration (e.g., 100/200MHz for UHS modes)
> is applied before DDR_EN is set. Only restore for non-wakeup devices
> since wakeup devices kept their active pin state during suspend.
> 
> Fixes: 676a83855614 ("mmc: host: sdhci-esdhc-imx: refactor the system PM logic")
> Signed-off-by: Luke Wang <ziniu.wang_1@xxxxxxx>

Reviewed-by: Haibo Chen <haibo.chen@xxxxxxx>

Regards
Haibo Chen
> ---
>  drivers/mmc/host/sdhci-esdhc-imx.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index a944351dbcdf..7fcaecdd4ec6 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -2114,6 +2114,12 @@ static int sdhci_esdhc_resume(struct device *dev)
>  	struct pltfm_imx_data *imx_data = sdhci_pltfm_priv(pltfm_host);
>  	int ret;
>  
> +	if (!device_may_wakeup(dev)) {
> +		ret = esdhc_change_pinstate(host, host->timing);
> +		if (ret)
> +			dev_warn(dev, "Failed to restore pinctrl state\n");
> +	}
> +
>  	pm_runtime_force_resume(dev);
>  
>  	ret = mmc_gpio_set_cd_wake(host->mmc, false);
> -- 
> 2.34.1
>