[PATCH 2/2] mmc: core: Use the ios vdd when calculating vqmmc for 3.3V signaling

[Shawn Lin]

mmc_regulator_set_vqmmc() takes an ios pointer and switches on its
signal_voltage, but the MMC_SIGNAL_VOLTAGE_330 path looks up the VMMC
voltage range using mmc->ios.vdd instead of ios->vdd. That mixes the
ios passed by the caller with the global mmc->ios state, which do not
have to agree.

mmc_set_signal_voltage() only updates host->ios.signal_voltage before
invoking ->start_signal_voltage_switch(); host->ios.vdd is refreshed
when the power supply is (re)configured, e.g. in mmc_power_up() after a
new OCR has been selected. A host driver switching the signal voltage
for a vdd that has not been committed to mmc->ios yet, or passing its
own ios snapshot, would therefore get a vqmmc range computed for the
previous, stale vdd instead of the signaling voltage it is switching
to. With a stale vdd of the 1.65-1.95V range, the computed 3.3V window
ends up with min_uV > max_uV and the vqmmc regulator is never set, so
the signaling switch fails.

Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>

---

 drivers/mmc/core/regulator.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mmc/core/regulator.c b/drivers/mmc/core/regulator.c
index a85179f..c553356 100644
--- a/drivers/mmc/core/regulator.c
+++ b/drivers/mmc/core/regulator.c
@@ -197,7 +197,7 @@ int mmc_regulator_set_vqmmc(struct mmc_host *mmc, struct mmc_ios *ios)
 		return mmc_regulator_set_voltage_if_supported(mmc->supply.vqmmc,
 						1700000, 1800000, 1950000);
 	case MMC_SIGNAL_VOLTAGE_330:
-		ret = mmc_ocrbitnum_to_vdd(mmc->ios.vdd, &volt, &max_uV);
+		ret = mmc_ocrbitnum_to_vdd(ios->vdd, &volt, &max_uV);
 		if (ret < 0)
 			return ret;
 
-- 
2.7.4