mmc: mmci: stm32: Check when the voltage switch procedure should be done

If the card has not been power cycled, it may still be using 1.8V
signaling. This situation is detected in mmc_sd_init_card function and
should be handled in mmci stm32 variant.  The host->pwr_reg variable is
also correctly protected with spin locks.

Fixes: 94b94a9 ("mmc: mmci_sdmmc: Implement signal voltage callbacks")
Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com>
Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Change-Id: Ie46dbe2b0d72291ee0874ee8fcebdf9f2f8391fa
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/linux-stm32/+/227066
Reviewed-by: CITOOLS <MDG-smet-aci-reviews@list.st.com>
Reviewed-by: CIBUILD <MDG-smet-aci-builds@list.st.com>
Reviewed-by: Christophe KERELLO <christophe.kerello@st.com>

Author: Yann-lms

drivers/mmc/host/mmci_stm32_sdmmc.c

@@ -475,8 +475,9 @@ static int sdmmc_vswitch(struct mmci_host *host, struct mmc_ios *ios)
 	u32 status;
 	int ret = 0;
 
-	if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
-		spin_lock_irqsave(&host->lock, flags);
+	spin_lock_irqsave(&host->lock, flags);
+	if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180 &&
+	    host->pwr_reg & MCI_STM32_VSWITCHEN) {
 		mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCH);
 		spin_unlock_irqrestore(&host->lock, flags);
 
@@ -492,8 +493,8 @@ static int sdmmc_vswitch(struct mmci_host *host, struct mmc_ios *ios)
 		spin_lock_irqsave(&host->lock, flags);
 		mmci_write_pwrreg(host, host->pwr_reg &
 				  ~(MCI_STM32_VSWITCHEN | MCI_STM32_VSWITCH));
-		spin_unlock_irqrestore(&host->lock, flags);
 	}
+	spin_unlock_irqrestore(&host->lock, flags);
 
 	return ret;
 }