[PATCH 4.2 240/258] mmc: sdhci-pxav3: disable clock inversion for HS MMC cards

From: Greg Kroah-Hartman
Date: Sat Oct 17 2015 - 23:01:27 EST


4.2-stable review patch. If anyone has any objections, please let me know.

------------------

From: Nadav Haklai <nadavh@xxxxxxxxxxx>

commit fa7964147da57b2d40c2db2b6ed98fb7dc934bff upstream.

According to 'FE-2946959' erratum the clock inversion option is
needed to support slow frequencies when the card input hold time
requirement is high. This setting is not required for high speed
MMC and might cause timing violation.

Signed-off-by: Nadav Haklai <nadavh@xxxxxxxxxxx>
Reviewed-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c
index 976cddd6d157..89a9e49e2ea8 100644
--- a/drivers/mmc/host/sdhci-pxav3.c
+++ b/drivers/mmc/host/sdhci-pxav3.c
@@ -291,6 +291,9 @@ static void pxav3_set_uhs_signaling(struct sdhci_host *host, unsigned int uhs)
uhs == MMC_TIMING_UHS_DDR50) {
reg_val &= ~SDIO3_CONF_CLK_INV;
reg_val |= SDIO3_CONF_SD_FB_CLK;
+ } else if (uhs == MMC_TIMING_MMC_HS) {
+ reg_val &= ~SDIO3_CONF_CLK_INV;
+ reg_val &= ~SDIO3_CONF_SD_FB_CLK;
} else {
reg_val |= SDIO3_CONF_CLK_INV;
reg_val &= ~SDIO3_CONF_SD_FB_CLK;


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