mmc: usdhi6rol0: add pinctrl to set pin drive strength

Some boards need different pin drive strength for the UHS mode. Add an
optional pinctrl setting with two pin states covering UHS speeds and
other speeds.

Signed-off-by: Lars Persson <[e-mail]>
Signed-off-by: Ulf Hansson <[e-mail]>

drivers/mmc/host/usdhi6rol0.c

···
 #include <linux/mmc/sdio.h>
 #include <linux/module.h>
 #include <linux/pagemap.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
 #include <linux/scatterlist.h>
 #include <linux/string.h>
···
 	struct dma_chan *chan_rx;
 	struct dma_chan *chan_tx;
 	bool dma_active;
+
+	/* Pin control */
+	struct pinctrl *pinctrl;
+	struct pinctrl_state *pins_default;
+	struct pinctrl_state *pins_uhs;
 };
 
 /*			I/O primitives					*/
···
 	}
 }
 
+static int usdhi6_set_pinstates(struct usdhi6_host *host, int voltage)
+{
+	if (IS_ERR(host->pins_uhs))
+		return 0;
+
+	switch (voltage) {
+	case MMC_SIGNAL_VOLTAGE_180:
+	case MMC_SIGNAL_VOLTAGE_120:
+		return pinctrl_select_state(host->pinctrl,
+					    host->pins_uhs);
+
+	default:
+		return pinctrl_select_state(host->pinctrl,
+					    host->pins_default);
+	}
+}
+
 static int usdhi6_sig_volt_switch(struct mmc_host *mmc, struct mmc_ios *ios)
 {
 	int ret;
 
 	ret = mmc_regulator_set_vqmmc(mmc, ios);
+	if (ret < 0)
+		return ret;
 
+	ret = usdhi6_set_pinstates(mmc_priv(mmc), ios->signal_voltage);
+	if (ret)
+		dev_warn_once(mmc_dev(mmc),
+			      "Failed to set pinstate err=%d\n", ret);
 	return ret;
 }
 
···
 	host->mmc	= mmc;
 	host->wait	= USDHI6_WAIT_FOR_REQUEST;
 	host->timeout	= msecs_to_jiffies(4000);
+
+	host->pinctrl = devm_pinctrl_get(&pdev->dev);
+	if (IS_ERR(host->pinctrl)) {
+		ret = PTR_ERR(host->pinctrl);
+		goto e_free_mmc;
+	}
+
+	host->pins_uhs = pinctrl_lookup_state(host->pinctrl, "state_uhs");
+	if (!IS_ERR(host->pins_uhs)) {
+		host->pins_default = pinctrl_lookup_state(host->pinctrl,
+							  PINCTRL_STATE_DEFAULT);
+
+		if (IS_ERR(host->pins_default)) {
+			dev_err(dev,
+				"UHS pinctrl requires a default pin state.\n");
+			ret = PTR_ERR(host->pins_default);
+			goto e_free_mmc;
+		}
+	}
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	host->base = devm_ioremap_resource(dev, res);