mmc: sdhci: Fix to handle MMC_POWER_UNDEFINED

Since commit c2c24819 ("mmc: core: Don't power off the card when
starting the host"), the power state can still be MMC_POWER_UNDEFINED after
mmc_start_host() is called. That can trigger a warning in SDHCI during
runtime resume as it tries to restore the I/O state. Handle
MMC_POWER_UNDEFINED simply by not updating the I/O state in that case.

Fixes: c2c24819 ("mmc: core: Don't power off the card when starting the host")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci.c

@@ -1576,6 +1576,9 @@ static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 	unsigned long flags;
 	u8 ctrl;
 
+	if (ios->power_mode == MMC_POWER_UNDEFINED)
+		return;
+
 	spin_lock_irqsave(&host->lock, flags);
 
 	if (host->flags & SDHCI_DEVICE_DEAD) {
@@ -2938,22 +2941,24 @@ int sdhci_runtime_resume_host(struct sdhci_host *host)
 
 	sdhci_init(host, 0);
 
-	/* Force clock and power re-program */
-	host->pwr = 0;
-	host->clock = 0;
-	mmc->ops->start_signal_voltage_switch(mmc, &mmc->ios);
-	mmc->ops->set_ios(mmc, &mmc->ios);
+	if (mmc->ios.power_mode != MMC_POWER_UNDEFINED) {
+		/* Force clock and power re-program */
+		host->pwr = 0;
+		host->clock = 0;
+		mmc->ops->start_signal_voltage_switch(mmc, &mmc->ios);
+		mmc->ops->set_ios(mmc, &mmc->ios);
 
-	if ((host_flags & SDHCI_PV_ENABLED) &&
-		!(host->quirks2 & SDHCI_QUIRK2_PRESET_VALUE_BROKEN)) {
-		spin_lock_irqsave(&host->lock, flags);
-		sdhci_enable_preset_value(host, true);
-		spin_unlock_irqrestore(&host->lock, flags);
-	}
+		if ((host_flags & SDHCI_PV_ENABLED) &&
+		    !(host->quirks2 & SDHCI_QUIRK2_PRESET_VALUE_BROKEN)) {
+			spin_lock_irqsave(&host->lock, flags);
+			sdhci_enable_preset_value(host, true);
+			spin_unlock_irqrestore(&host->lock, flags);
+		}
 
-	if ((mmc->caps2 & MMC_CAP2_HS400_ES) &&
-	    mmc->ops->hs400_enhanced_strobe)
-		mmc->ops->hs400_enhanced_strobe(mmc, &mmc->ios);
+		if ((mmc->caps2 & MMC_CAP2_HS400_ES) &&
+		    mmc->ops->hs400_enhanced_strobe)
+			mmc->ops->hs400_enhanced_strobe(mmc, &mmc->ios);
+	}
 
 	spin_lock_irqsave(&host->lock, flags);