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mmc: sdhci-of-esdhc: add workaround for pre divider initial value

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For eSDHC(version < 2.3), the pre divider only could divide base clock
by 2 at least. Add workaround for this to avoid unexpected issue.

Signed-off-by: Yangbo Lu <yangbo.lu@freescale.com>
Acked-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Fixes: bd455029d0 ("mmc: sdhci-of-esdhc: Pre divider starts at 1")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Yangbo Lu 2015-08-11 10:53:34 +08:00 committed by Ulf Hansson
parent d31911b937
commit 77bd2f6f6c
1 changed files with 6 additions and 0 deletions
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6
drivers/mmc/host/sdhci-of-esdhc.c
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@ -208,6 +208,12 @@ static void esdhc_of_set_clock(struct sdhci_host *host, unsigned int clock)
if (clock == 0)
return;
/* Workaround to start pre_div at 2 for VNN < VENDOR_V_23 */
temp = esdhc_readw(host, SDHCI_HOST_VERSION);
temp = (temp & SDHCI_VENDOR_VER_MASK) >> SDHCI_VENDOR_VER_SHIFT;
if (temp < VENDOR_V_23)
pre_div = 2;
/* Workaround to reduce the clock frequency for p1010 esdhc */
if (of_find_compatible_node(NULL, NULL, "fsl,p1010-esdhc")) {
if (clock > 20000000)