Re: [PATCH v2 3/5] mmc: sdhci-esdhc-imx: restore pinctrl before restoring ios timing on resume

[Frank Li]

On Thu, Jun 25, 2026 at 06:59:32PM +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. When DDR_EN is set while the pinctrl is still
> muxed to GPIO or other non-uSDHC function, the loopback clock from the
> external pad is not valid, resulting in an incorrect internal sampling
> point being selected. This causes persistent read CRC errors on subsequent
> data transfers, even after the pinctrl is later configured correctly.
>
> 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. Only restore for non-wakeup devices since wakeup devices
> kept their active pin state during suspend to avoid glitching the SD
> bus pins for powered SDIO cards.

pin state change should only impact driver strength, why cause glitch ?

Frank
>
> Fixes: 676a83855614 ("mmc: host: sdhci-esdhc-imx: refactor the system PM logic")
> Signed-off-by: Luke Wang <ziniu.wang_1@xxxxxxx>
> ---
>  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
>
>