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mmc: sdhci-of-esdhc: temporary fixup for eMMC HS400 issue
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Currently only LX2160A eSDHC supports eMMC HS400. According to
a large number of tests, eMMC HS400 failed to work at 150MHz,
and for a few boards failed to work at 175MHz. But eMMC HS400
worked fine on 200MHz. We hadn't found the root cause but
setting eSDHC_DLLCFG0[DLL_FREQ_SEL] = 0 using slow delay chain
seemed to resovle this issue. Let's use this as fixup for now.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
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Yangbo Lu authored and Ulf Hansson committed Dec 17, 2018
1 parent 6079e63 commit 58d0bf8
Showing 1 changed file with 3 additions and 1 deletion.
4 changes: 3 additions & 1 deletion drivers/mmc/host/sdhci-of-esdhc.c
Original file line number Diff line number Diff line change
Expand Up @@ -623,7 +623,9 @@ static void esdhc_of_set_clock(struct sdhci_host *host, unsigned int clock)
esdhc_clock_enable(host, true);

temp = sdhci_readl(host, ESDHC_DLLCFG0);
temp |= ESDHC_DLL_ENABLE | ESDHC_DLL_FREQ_SEL;
temp |= ESDHC_DLL_ENABLE;
if (host->mmc->actual_clock == MMC_HS200_MAX_DTR)
temp |= ESDHC_DLL_FREQ_SEL;
sdhci_writel(host, temp, ESDHC_DLLCFG0);
temp = sdhci_readl(host, ESDHC_TBCTL);
sdhci_writel(host, temp | ESDHC_HS400_WNDW_ADJUST, ESDHC_TBCTL);
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