mmc: fsl_esdhc: enable HS400 feature
The strobe dll code is ported from Linux Kernel:
drivers/mmc/host/sdhci-esdhc-imx.c
The comments are from the above file,
"For HS400 eMMC, there is a data_strobe line. This signal is generated
by the device and used for data output and CRC status response output
in HS400 mode. The frequency of this signal follows the frequency of
CLK generated by host. The host receives the data which is aligned to the
edge of data_strobe line. Due to the time delay between CLK line and
data_strobe line, if the delay time is larger than one clock cycle,
then CLK and data_strobe line will be misaligned, read error shows up.
So when the CLK is higher than 100MHz, each clock cycle is short enough,
host should configure the delay target. "
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Stefano Babic <sbabic@denx.de>
1 file changed