> From: BOUGH CHEN > Sent: Monday, April 29, 2019 4:56 PM > Subject: [PATCH v2 3/3] mmc: add HS400 support for iMX7ULP > > Add HS400 support for iMX7ULP B0. > > According to IC suggest, need to clear the STROBE_DLL_CTRL_RESET before any > setting of STROBE_DLL_CTRL register. > > USDHC has register bits(bit[27~20] of register STROBE_DLL_CTRL) for slave sel > value. If this register bits value is 0, it needs > 256 ref_clk cycles to update slave sel value. IC suggest to set bit[27~20] to 0x4, > it only need 4 ref_clk cycle to update slave sel value. This will short the lock > time of slave. > > i.MX7ULP B0 will need more time to lock the REF and SLV, so change to add > 5us delay. > > Signed-off-by: Haibo Chen <haibo.chen@xxxxxxx> mmc: sdhci-esdhc-imx: add HS400 support for iMX7ULP otherwise: Reviewed-by: Dong Aisheng <aisheng.dong@xxxxxxx> Regards Dong Aisheng
