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 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html