mmc: mmci: Add support for setting pad type via pinctrl

If variant hasn't the control bit to switch pads in opendrain mode,
we can achieve the same result by asking to the pinmux driver to
configure pins for us.

This patch make the mmci driver able to do this whenever needed.
Signed-off-by: Andrea Merello <andrea.merello@gmail.com>
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/mmci.c

@@ -1465,8 +1465,19 @@ static void mmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 				~MCI_ST_DATA2DIREN);
 	}
 
-	if (ios->bus_mode == MMC_BUSMODE_OPENDRAIN && variant->opendrain)
-		pwr |= variant->opendrain;
+	if (variant->opendrain) {
+		if (ios->bus_mode == MMC_BUSMODE_OPENDRAIN)
+			pwr |= variant->opendrain;
+	} else {
+		/*
+		 * If the variant cannot configure the pads by its own, then we
+		 * expect the pinctrl to be able to do that for us
+		 */
+		if (ios->bus_mode == MMC_BUSMODE_OPENDRAIN)
+			pinctrl_select_state(host->pinctrl, host->pins_opendrain);
+		else
+			pinctrl_select_state(host->pinctrl, host->pins_default);
+	}
 
 	/*
 	 * If clock = 0 and the variant requires the MMCIPOWER to be used for
@@ -1610,6 +1621,32 @@ static int mmci_probe(struct amba_device *dev,
 	host = mmc_priv(mmc);
 	host->mmc = mmc;
 
+	/*
+	 * Some variant (STM32) doesn't have opendrain bit, nevertheless
+	 * pins can be set accordingly using pinctrl
+	 */
+	if (!variant->opendrain) {
+		host->pinctrl = devm_pinctrl_get(&dev->dev);
+		if (IS_ERR(host->pinctrl)) {
+			dev_err(&dev->dev, "failed to get pinctrl");
+			goto host_free;
+		}
+
+		host->pins_default = pinctrl_lookup_state(host->pinctrl,
+							  PINCTRL_STATE_DEFAULT);
+		if (IS_ERR(host->pins_default)) {
+			dev_err(mmc_dev(mmc), "Can't select default pins\n");
+			goto host_free;
+		}
+
+		host->pins_opendrain = pinctrl_lookup_state(host->pinctrl,
+							    MMCI_PINCTRL_STATE_OPENDRAIN);
+		if (IS_ERR(host->pins_opendrain)) {
+			dev_err(mmc_dev(mmc), "Can't select opendrain pins\n");
+			goto host_free;
+		}
+	}
+
 	host->hw_designer = amba_manf(dev);
 	host->hw_revision = amba_rev(dev);
 	dev_dbg(mmc_dev(mmc), "designer ID = 0x%02x\n", host->hw_designer);

drivers/mmc/host/mmci.h

@@ -192,6 +192,8 @@
 
 #define NR_SG		128
 
+#define MMCI_PINCTRL_STATE_OPENDRAIN "opendrain"
+
 struct clk;
 struct variant_data;
 struct dma_chan;
@@ -227,6 +229,9 @@ struct mmci_host {
 	bool			vqmmc_enabled;
 	struct mmci_platform_data *plat;
 	struct variant_data	*variant;
+	struct pinctrl		*pinctrl;
+	struct pinctrl_state	*pins_default;
+	struct pinctrl_state	*pins_opendrain;
 
 	u8			hw_designer;
 	u8			hw_revision:4;