[PATCH 3/3] mmc: sdhci: Modify sdhci o2 quirk for eMMC HS200 tuning case

[LinuxPatchCommit]

Dear all,

Don't clear transfer mode register in sdhci_set_transfer_mode().

In sdhci_set_transfer_mode(), clear transfer mode quirk2 will clear SD host transfer mode register for non-data commands. This quirk is used for the bug of O2micro/Bayhubtech devices. In eMMC HS200 tuning case, the tuning process uses hardware tuning and it needs to set transfer mode register for tuning command.

Signed-off-by: ernest.zhang <ernest.zhang@xxxxxxxxxxxxxx>
---
 drivers/mmc/host/sdhci.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 0d5fcca18c9e..d5b19fc9ea56 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -918,7 +918,9 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host,
 	if (data == NULL) {
 		if (host->quirks2 &
 			SDHCI_QUIRK2_CLEAR_TRANSFERMODE_REG_BEFORE_CMD) {
-			sdhci_writew(host, 0x0, SDHCI_TRANSFER_MODE);
+			/* cannot clear transfer mode register when tuning */
+			if (cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200)
+				sdhci_writew(host, 0x0, SDHCI_TRANSFER_MODE);
 		} else {
 		/* clear Auto CMD settings for no data CMDs */
 			mode = sdhci_readw(host, SDHCI_TRANSFER_MODE);
--
2.14.1