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

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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>

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yangbo lu 2016-12-26 17:46:30 +08:00 • committed by Ulf Hansson

parent c31165d740

commit e87d2db2a2

2 changed files with 23 additions and 3 deletions

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5

drivers/mmc/host/sdhci-esdhc.h

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21

drivers/mmc/host/sdhci-of-esdhc.c

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