tree c9734f8a622d35cb2b4758779fafe56cb8a6a702
parent c31165d7400bb1ec12291170c9c4d072d5b0ba45
author yangbo lu <yangbo.lu@nxp.com> 1482745590 +0800
committer Ulf Hansson <ulf.hansson@linaro.org> 1486988415 +0100

mmc: sdhci-of-esdhc: avoid clock glitch when frequency is changing

The eSDHC_PRSSTAT[SDSTB] bit indicates whether the internal card clock is
stable. This bit is for the host driver to poll clock status when changing
the clock frequency. It is recommended to clear eSDHC_SYSCTL[SDCLKEN]
to remove glitch on the card clock when the frequency is changing. This
patch is to disable SDCLKEN bit before changing frequency and enable it
after SDSTB bit is set.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>