mmc: mmc: Fix incorrect use of driver strength switching HS200 and HS400

Commit cc4f414c885c ("mmc: mmc: Add driver strength selection")
added driver strength selection for eMMC HS200 and HS400 modes.
That patch also set the driver stength when transitioning through
High Speed mode to HS200/HS400, but driver strength is not defined
for High Speed mode.  While the JEDEC specification is not clear
on this point it has been observed to cause problems for some eMMC,
and removing the driver strength setting in this case makes it
consistent with the normal use of High Speed mode.

Signed-off-by: Wenkai Du <wenkai.du@intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v4.2+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 66957addf9e4de7ca93623e133e90183404f42bc..549c56e8cf6bc9753a17fc80dafbb5304bc43c45 100644 (file)
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1076,8 +1076,7 @@ static int mmc_select_hs400(struct mmc_card *card)
        mmc_set_clock(host, max_dtr);
 
        /* Switch card to HS mode */
-       val = EXT_CSD_TIMING_HS |
-             card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
+       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,
@@ -1160,8 +1159,7 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
        mmc_set_clock(host, max_dtr);
 
        /* Switch HS400 to HS DDR */
-       val = EXT_CSD_TIMING_HS |
-             card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
+       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,
                           true, send_status, true);