2017-05-19 21:24 GMT+09:00 Masahiro Yamada yamada.masahiro@socionext.com:
The MMC framework in U-Boot does not support a systematic API for timing switch like mmc_set_timing() in Linux.
U-Boot just provides a hook to change the clock frequency via mmc_set_clock(). It is up to drivers if additional register settings are needed.
This driver needs to set a correct timing mode into a register when it migrates to a different speed mode. Only increasing clock frequency could result in setup/hold timing violation.
The timing mode should be decided by checking MMC_TIMING_* like drivers/mmc/host/sdhci-cadence.c in Linux, but "timing" is not supported by U-Boot for now. Just use mmc->clock to decide the timing mode.
Signed-off-by: Masahiro Yamada yamada.masahiro@socionext.com
I see lots of improvements for MMC core.
Looks like it is better to rebase my work after they are merged.
I marked this patch Superseded.