mmc: sdhci: Introduce sdhci_set_power_and_bus_voltage()

Some controllers diverge from the standard way of setting power and need
their bus voltage register to be configured regardless of the whether
they use regulators. As this is a common pattern across sdhci hosts,
create a helper function.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200306174413.20634-2-nsaenzjulienne@suse.de
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci.c

@@ -2010,6 +2010,25 @@ void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
 }
 EXPORT_SYMBOL_GPL(sdhci_set_power);
 
+/*
+ * Some controllers need to configure a valid bus voltage on their power
+ * register regardless of whether an external regulator is taking care of power
+ * supply. This helper function takes care of it if set as the controller's
+ * sdhci_ops.set_power callback.
+ */
+void sdhci_set_power_and_bus_voltage(struct sdhci_host *host,
+				     unsigned char mode,
+				     unsigned short vdd)
+{
+	if (!IS_ERR(host->mmc->supply.vmmc)) {
+		struct mmc_host *mmc = host->mmc;
+
+		mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, vdd);
+	}
+	sdhci_set_power_noreg(host, mode, vdd);
+}
+EXPORT_SYMBOL_GPL(sdhci_set_power_and_bus_voltage);
+
 /*****************************************************************************\
  *                                                                           *
  * MMC callbacks                                                             *

drivers/mmc/host/sdhci.h

@@ -772,6 +772,9 @@ void sdhci_set_clock(struct sdhci_host *host, unsigned int clock);
 void sdhci_enable_clk(struct sdhci_host *host, u16 clk);
 void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
 		     unsigned short vdd);
+void sdhci_set_power_and_bus_voltage(struct sdhci_host *host,
+				     unsigned char mode,
+				     unsigned short vdd);
 void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
 			   unsigned short vdd);
 void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq);