mmc: uniphier-sd: Add control of UHS mode using SD interface logic

Transition of UHS mode needs to control the register in SD interface
logic. Add access to the register in the logic using the regmap from
"socionext,syscon-uhs-mode" property.

Define the start_signal_voltage_switch function only if UHS mode is
available.
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Link: https://lore.kernel.org/r/20230125010201.28246-3-hayashi.kunihiko@socionext.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/uniphier-sd.c

@@ -8,6 +8,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
+#include <linux/mfd/syscon.h>
 #include <linux/mfd/tmio.h>
 #include <linux/mmc/host.h>
 #include <linux/module.h>
@@ -15,6 +16,7 @@
 #include <linux/of_device.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
+#include <linux/regmap.h>
 #include <linux/reset.h>
 
 #include "tmio_mmc.h"
@@ -48,6 +50,11 @@
 #define UNIPHIER_SD_DMA_ADDR_L		0x440
 #define UNIPHIER_SD_DMA_ADDR_H		0x444
 
+/* SD control */
+#define UNIPHIER_SDCTRL_CHOFFSET	0x200
+#define UNIPHIER_SDCTRL_MODE		0x30
+#define   UNIPHIER_SDCTRL_MODE_UHS1MOD		BIT(15)
+
 /*
  * IP is extended to support various features: built-in DMA engine,
  * 1/1024 divisor, etc.
@@ -66,6 +73,8 @@ struct uniphier_sd_priv {
 	struct reset_control *rst_hw;
 	struct dma_chan *chan;
 	enum dma_data_direction dma_dir;
+	struct regmap *sdctrl_regmap;
+	u32 sdctrl_ch;
 	unsigned long clk_rate;
 	unsigned long caps;
 };
@@ -420,6 +429,23 @@ static void uniphier_sd_hw_reset(struct mmc_host *mmc)
 	usleep_range(300, 1000);
 }
 
+static void uniphier_sd_uhs_enable(struct tmio_mmc_host *host, bool uhs_en)
+{
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+	unsigned int offset;
+	u32 val;
+
+	if (!(host->mmc->caps & MMC_CAP_UHS))
+		return;
+
+	val = (uhs_en) ? UNIPHIER_SDCTRL_MODE_UHS1MOD : 0;
+
+	offset = UNIPHIER_SDCTRL_CHOFFSET * priv->sdctrl_ch
+		+ UNIPHIER_SDCTRL_MODE;
+	regmap_write_bits(priv->sdctrl_regmap, offset,
+			  UNIPHIER_SDCTRL_MODE_UHS1MOD, val);
+}
+
 static void uniphier_sd_set_clock(struct tmio_mmc_host *host,
 				  unsigned int clock)
 {
@@ -500,14 +526,17 @@ static int uniphier_sd_start_signal_voltage_switch(struct mmc_host *mmc,
 	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
 	struct pinctrl_state *pinstate = NULL;
 	u32 val, tmp;
+	bool uhs_en;
 
 	switch (ios->signal_voltage) {
 	case MMC_SIGNAL_VOLTAGE_330:
 		val = UNIPHIER_SD_VOLT_330;
+		uhs_en = false;
 		break;
 	case MMC_SIGNAL_VOLTAGE_180:
 		val = UNIPHIER_SD_VOLT_180;
 		pinstate = priv->pinstate_uhs;
+		uhs_en = true;
 		break;
 	default:
 		return -ENOTSUPP;
@@ -523,12 +552,19 @@ static int uniphier_sd_start_signal_voltage_switch(struct mmc_host *mmc,
 	else
 		pinctrl_select_default_state(mmc_dev(mmc));
 
+	uniphier_sd_uhs_enable(host, uhs_en);
+
 	return 0;
 }
 
-static int uniphier_sd_uhs_init(struct tmio_mmc_host *host,
-				struct uniphier_sd_priv *priv)
+static int uniphier_sd_uhs_init(struct tmio_mmc_host *host)
 {
+	struct uniphier_sd_priv *priv = uniphier_sd_priv(host);
+	struct device *dev = &host->pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct of_phandle_args args;
+	int ret;
+
 	priv->pinctrl = devm_pinctrl_get(mmc_dev(host->mmc));
 	if (IS_ERR(priv->pinctrl))
 		return PTR_ERR(priv->pinctrl);
@@ -537,8 +573,20 @@ static int uniphier_sd_uhs_init(struct tmio_mmc_host *host,
 	if (IS_ERR(priv->pinstate_uhs))
 		return PTR_ERR(priv->pinstate_uhs);
 
-	host->ops.start_signal_voltage_switch =
-					uniphier_sd_start_signal_voltage_switch;
+	ret = of_parse_phandle_with_fixed_args(np,
+					       "socionext,syscon-uhs-mode",
+					       1, 0, &args);
+	if (ret) {
+		dev_err(dev, "Can't get syscon-uhs-mode property\n");
+		return ret;
+	}
+	priv->sdctrl_regmap = syscon_node_to_regmap(args.np);
+	of_node_put(args.np);
+	if (IS_ERR(priv->sdctrl_regmap)) {
+		dev_err(dev, "Can't map syscon-uhs-mode\n");
+		return PTR_ERR(priv->sdctrl_regmap);
+	}
+	priv->sdctrl_ch = args.args[0];
 
 	return 0;
 }
@@ -601,12 +649,15 @@ static int uniphier_sd_probe(struct platform_device *pdev)
 	}
 
 	if (host->mmc->caps & MMC_CAP_UHS) {
-		ret = uniphier_sd_uhs_init(host, priv);
+		ret = uniphier_sd_uhs_init(host);
 		if (ret) {
 			dev_warn(dev,
 				 "failed to setup UHS (error %d).  Disabling UHS.",
 				 ret);
 			host->mmc->caps &= ~MMC_CAP_UHS;
+		} else {
+			host->ops.start_signal_voltage_switch =
+				uniphier_sd_start_signal_voltage_switch;
 		}
 	}