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>
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