Re: [PATCH 1/3] arm64: dts: imx93-11x11-evk: set SION for cmd and data pad of USDHC

[Shawn Guo <shawnguo@kernel.org>]

On Tue, Oct 17, 2023 at 02:50:46PM +0800, haibo.chen@nxp.com wrote:
> From: Haibo Chen <haibo.chen@nxp.com>
> 
> imx93 pad integrate has one issue, refer to ERR052021:
> 
> ERR052021 uSDHC: Sometimes uSDHC does not work under VDD_SOC low
> 		 drive mode and nominal mode
> Description:
> uSDHC PADs have one integration issue.
> When CMD/DATA lines direction change from output to input, uSDHC
> controller begin sampling, the integration issue will make input
> enable signal from uSDHC propagated to the PAD with a long delay,
> thus the new input value on the pad comes to uSDHC lately. The
> uSDHC sampled the old input value and the sampling result is wrong.
> 
> Workaround:
> Set uSDHC CMD/DATA PADs iomux register SION bit to 1, then PADs will
> propagate input to uSDHC with no delay, so correct value is sampled.
> 
> This issue will wrongly trigger the start bit when sample the USDHC
> command response, cause the USDHC trigger command CRC/index/endbit
> error, which will finally impact the tuning pass window, espically
> will impact the standard tuning logic, and can't find a correct delay
> cell to get the best timing.
> 
> Signed-off-by: Haibo Chen <haibo.chen@nxp.com>

Applied all, thanks!