[PATCH RFC 3/3] mmc: core: Do not change frequency before switch from HS400

[Adrian Hunter <adrian.hunter@intel.com>]

Do not change frequency before switch from HS400 but in case of error
try again after frequency change.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/core/mmc.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 3e2ad728b55e..e2b3d7505d6c 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1235,20 +1235,27 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
 	int err;
 	u8 val;
 
-	/* Reduce frequency to HS */
-	max_dtr = card->ext_csd.hs_max_dtr;
-	mmc_set_clock(host, max_dtr);
-
 	/* Switch HS400 to HS DDR */
 	val = EXT_CSD_TIMING_HS;
 	err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING,
 			   val, card->ext_csd.generic_cmd6_time, 0,
 			   false, true, true);
-	if (err)
-		goto out_err;
 
 	mmc_set_timing(host, MMC_TIMING_MMC_DDR52);
 
+	/* Reduce frequency to HS */
+	max_dtr = card->ext_csd.hs_max_dtr;
+	mmc_set_clock(host, max_dtr);
+
+	if (err) {
+		err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+				   EXT_CSD_HS_TIMING, val,
+				   card->ext_csd.generic_cmd6_time, 0, false,
+				   true, true);
+	}
+	if (err)
+		goto out_err;
+
 	err = mmc_switch_status(card, true);
 	if (err)
 		goto out_err;
-- 
2.17.1