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authorWenkai Du <wenkai.du@intel.com>2015-11-26 14:00:44 +0200
committerUlf Hansson <ulf.hansson@linaro.org>2015-12-22 11:32:13 +0100
commitadb24d42a516bca8b9741ed21206509daaab5b13 (patch)
tree7c7bcf2b646979be3b7679aaf040be864ad92cc7 /drivers/mmc
parent100a606d54a087cfec54efbedba72f36e5a9cdf0 (diff)
downloadlinux-adb24d42a516bca8b9741ed21206509daaab5b13.tar.bz2
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>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/core/mmc.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 66957addf9e4..549c56e8cf6b 100644
--- 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);