[PATCH v4 3/4] mmc: dw_mmc: Always setup the bus after suspend/resume

From: Doug Anderson
Date: Tue Aug 06 2013 - 17:38:13 EST

After suspend/resume all of the dw_mmc registers are reset to
defaults. We restore most of them, but specifically don't setup the
clock registers after resume unless we've got a powered card. Things
still work because the core will eventually call set_ios() and we'll
set things up.

There doesn't seem to be any reason that I can see _not_ to set things
up after resume. Restoring this state makes the code easier to reason
about and should help prevent bugs. It also allows us to do a
register dump before and after suspend/resume to confirm that we've
set things up OK.

I examined the state of the dw_mmc instance before and after suspend
after this patch. I had no card inserted in an SD card slot.

Before this patch, differences were:
* CLKDIV (0x08)
* CLKENA (0x10)
* TMOUT (0x14)
* CMD (0x2C) - difference is not important
* CLKSEL (0x9C - exynos specific)

After this patch, only TMOUT was different. I have a separate patch
for that.

Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
Changes in v4: None
Changes in v3: None
Changes in v2: None

drivers/mmc/host/dw_mmc.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 13a363c..0fa3135 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -2522,9 +2522,7 @@ int dw_mci_resume(struct dw_mci *host)
struct dw_mci_slot *slot = host->slot[i];
if (!slot)
- if (slot->mmc->pm_flags & MMC_PM_KEEP_POWER) {
- dw_mci_set_ios(slot->mmc, &slot->mmc->ios);
- }
+ dw_mci_set_ios(slot->mmc, &slot->mmc->ios);

ret = mmc_resume_host(host->slot[i]->mmc);
if (ret < 0)

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