diff options
| author | xiaoyao <xiaoyao@rock-chips.com> | 2016-09-22 17:21:24 +0800 |
|---|---|---|
| committer | Huang, Tao <huangtao@rock-chips.com> | 2016-09-23 17:08:41 +0800 |
| commit | 5b0edb353a0eab4abd466682b7099147a3d573f0 (patch) | |
| tree | 6011d313aff5f709202aac913bd061b27258a189 /drivers | |
| parent | 09c5c21b64168183edbac38e7752b7fc5bb0fe9f (diff) | |
mmc: core: changes frequency to hs_max_dtr when selecting hs400es
Per JESD84-B51 P69, Host need to change frequency to <=52MHz after
setting HS_TIMING to 0x1, and host may changes frequency to <= 200MHz
after setting HS_TIMING to 0x3. It seems there is no difference if
we don't change frequency to <= 52MHz as f_init is already less than
52MHz. But actually it does make difference. When doing compatibility
test we see failures for some eMMC devices without changing the
frequency to hs_max_dtr. And let's read the spec again, we could see
that "Host may changes frequency to 200MHz" implies that it's not
mandatory. But the "Host need to change frequency to <= 52MHz" implies
that we should do this.
Change-Id: I1dc9f5fa8dc217e033fc4b1689ca1b0204c294c0
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: xiaoyao <xiaoyao@rock-chips.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/mmc/core/mmc.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index ed5d54dd7c4e..3c2c026f66cd 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -1266,6 +1266,8 @@ static int mmc_select_hs400es(struct mmc_card *card) if (err) goto out_err; + mmc_set_clock(host, card->ext_csd.hs_max_dtr); + err = mmc_switch_status(card); if (err) goto out_err; |