linux-kernel - Re: [PATCH] mmc: sdhci-esdhc-imx: inherit pins_100mhz from pins

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Message-ID: <aC31QJpomsFWN++7@lizhi-Precision-Tower-5810>
Date: Wed, 21 May 2025 11:46:08 -0400
From: Frank Li <Frank.li@....com>
To: ziniu.wang_1@....com
Cc: haibo.chen@....com, adrian.hunter@...el.com, ulf.hansson@...aro.org,
	linux-mmc@...r.kernel.org, shawnguo@...nel.org,
	s.hauer@...gutronix.de, kernel@...gutronix.de, festevam@...il.com,
	imx@...ts.linux.dev, s32@....com,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mmc: sdhci-esdhc-imx: inherit pins_100mhz from
 pins_200mhz when unconfigured

On Wed, May 21, 2025 at 07:20:42PM +0800, ziniu.wang_1@....com wrote:
> From: Luke Wang <ziniu.wang_1@....com>
>
> On some new i.MX platforms, hardware guidelines recommend using identical
> pin configurations for SDR50/DDR50 (100MHz) and SDR104/HS400 (200MHz)
> modes. But defining two identical pinctrl for 100MHz and 200MHz in dts
> creates redundancy. In this case, omit explicit 100MHz configuration,
> driver will inherit 100MHz pinctrl from 200MHz.

It is quite strange inherit low freq setting from high freq setting.

Orignal method that decide support SDR50/DDR50/SDR104/HS400 abuse the
pinctrl state usage.

Frank

>
> Preserves existing behavior if 100MHz is configured but 200MHz not (e.g,
> imx8mp-navq.dts usdhc1 supports SDR50/DDR50 but SDR104/HS400 not).
>
> Signed-off-by: Luke Wang <ziniu.wang_1@....com>
> ---
>  drivers/mmc/host/sdhci-esdhc-imx.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index f206b562a6e3..dfd8be5000c8 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -1810,6 +1810,9 @@ sdhci_esdhc_imx_probe_dt(struct platform_device *pdev,
>  						ESDHC_PINCTRL_STATE_100MHZ);
>  		imx_data->pins_200mhz = pinctrl_lookup_state(imx_data->pinctrl,
>  						ESDHC_PINCTRL_STATE_200MHZ);
> +
> +		if (IS_ERR_OR_NULL(imx_data->pins_100mhz))
> +			imx_data->pins_100mhz = imx_data->pins_200mhz;
>  	}
>
>  	/* call to generic mmc_of_parse to support additional capabilities */
> --
> 2.34.1
>