• Haibo Chen's avatar
    arm64: dts: imx93-11x11-evk: set SION for cmd and data pad of USDHC · bb896012
    Haibo Chen authored
    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: default avatarHaibo Chen <haibo.chen@nxp.com>
    Signed-off-by: default avatarShawn Guo <shawnguo@kernel.org>
    bb896012
imx93-11x11-evk.dts 6.37 KB