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authorWenkai Du <wenkai.du@intel.com>2015-11-26 14:00:44 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-03-03 15:07:15 -0800
commit6eec26b7b07ece01ad547fce01f0229c733f6462 (patch)
tree5ddd5300fef5063769106a8d3f6701cbcc27ba7f /drivers/mmc
parent8ae7192d91c8ca19fd0b919b594bc317d33fbede (diff)
mmc: mmc: Fix incorrect use of driver strength switching HS200 and HS400
commit adb24d42a516bca8b9741ed21206509daaab5b13 upstream. 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> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 3a9a79ec4343..3d5087b03999 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);