[PATCH v2 1/3] arm64: dts: imx93-9x9-qsb: change usdhc tuning step for eMMC and SD

[Luke Wang]

> -----Original Message-----
> From: Peng Fan (OSS) <peng.fan at oss.nxp.com>
> Sent: Monday, February 2, 2026 11:40 AM
> To: Luke Wang <ziniu.wang_1 at nxp.com>
> Cc: shawnguo at kernel.org; s.hauer at pengutronix.de; Frank Li
> <frank.li at nxp.com>; robh at kernel.org; krzk+dt at kernel.org;
> conor+dt at kernel.org; kernel at pengutronix.de; festevam at gmail.com;
> devicetree at vger.kernel.org; imx at lists.linux.dev; linux-arm-
> kernel at lists.infradead.org; linux-kernel at vger.kernel.org
> Subject: Re: [PATCH v2 1/3] arm64: dts: imx93-9x9-qsb: change usdhc tuning
> step for eMMC and SD
> 
> On Thu, Jan 29, 2026 at 04:04:37PM +0800, ziniu.wang_1 at nxp.com wrote:
> >From: Luke Wang <ziniu.wang_1 at nxp.com>
> >
> >During system resume, the following errors occurred:
> >
> >  [  430.638625] mmc1: error -84 writing Cache Enable bit
> >  [  430.643618] mmc1: error -84 doing runtime resume
> >
> >For eMMC and SD, there are two tuning pass windows and the gap between
> >those two windows may only have one cell. If tuning step > 1, the gap may
> >just be skipped and host assumes those two windows as a continuous
> >windows. This will cause a wrong delay cell near the gap to be selected.
> >
> >Set the tuning step to 1 to avoid selecting the wrong delay cell.
> >
> >For SDIO, the gap is sufficiently large, so the default tuning step does
> >not cause this issue.
> 
> Adding a fix tag? one more question, I see all three patches are all
> changing to 1, could this change be in imx91_93_common.dtsi?

Will add fix tag in next version.
Tuning timing is related to board design. Costumer board may not need
to change to 1 if the gap is sufficiently large.

Regards,
Luke

> 
> Regards
> Peng
> 
> >
> >Signed-off-by: Luke Wang <ziniu.wang_1 at nxp.com>
> >---
> > arch/arm64/boot/dts/freescale/imx93-9x9-qsb.dts | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> >diff --git a/arch/arm64/boot/dts/freescale/imx93-9x9-qsb.dts
> b/arch/arm64/boot/dts/freescale/imx93-9x9-qsb.dts
> >index 0852067eab2c..197c8f8b7f66 100644
> >--- a/arch/arm64/boot/dts/freescale/imx93-9x9-qsb.dts
> >+++ b/arch/arm64/boot/dts/freescale/imx93-9x9-qsb.dts
> >@@ -507,6 +507,7 @@ &usdhc1 {
> > 	pinctrl-2 = <&pinctrl_usdhc1_200mhz>;
> > 	bus-width = <8>;
> > 	non-removable;
> >+	fsl,tuning-step = <1>;
> > 	status = "okay";
> > };
> >
> >@@ -519,6 +520,7 @@ &usdhc2 {
> > 	vmmc-supply = <&reg_usdhc2_vmmc>;
> > 	bus-width = <4>;
> > 	no-mmc;
> >+	fsl,tuning-step = <1>;
> > 	status = "okay";
> > };
> >
> >--
> >2.34.1
> >