mmc: sdhci-xenon: Add SoC PHY PAD voltage control

Some SoCs have PHY PAD outside Xenon IP.
PHY PAD voltage should match signalling voltage in use.

Add generic SoC PHY PAD voltage control interface.
Implement Aramda-3700 SoC PHY PAD voltage control.

Signed-off-by: Hu Ziji <huziji@marvell.com>
Tested-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-xenon-phy.c

@@ -143,6 +143,21 @@ enum xenon_phy_type_enum {
 	NR_PHY_TYPES
 };
 
+enum soc_pad_ctrl_type {
+	SOC_PAD_SD,
+	SOC_PAD_FIXED_1_8V,
+};
+
+struct soc_pad_ctrl {
+	/* Register address of SoC PHY PAD ctrl */
+	void __iomem	*reg;
+	/* SoC PHY PAD ctrl type */
+	enum soc_pad_ctrl_type pad_type;
+	/* SoC specific operation to set SoC PHY PAD */
+	void (*set_soc_pad)(struct sdhci_host *host,
+			    unsigned char signal_voltage);
+};
+
 static struct xenon_emmc_phy_regs xenon_emmc_5_0_phy_regs = {
 	.timing_adj	= XENON_EMMC_5_0_PHY_TIMING_ADJUST,
 	.func_ctrl	= XENON_EMMC_5_0_PHY_FUNC_CONTROL,
@@ -176,6 +191,8 @@ struct xenon_emmc_phy_params {
 	u8	nr_tun_times;
 	/* Divider for calculating Tuning Step */
 	u8	tun_step_divider;
+
+	struct soc_pad_ctrl pad_ctrl;
 };
 
 static int xenon_alloc_emmc_phy(struct sdhci_host *host)
@@ -254,6 +271,45 @@ static int xenon_emmc_phy_init(struct sdhci_host *host)
 	return 0;
 }
 
+#define ARMADA_3700_SOC_PAD_1_8V	0x1
+#define ARMADA_3700_SOC_PAD_3_3V	0x0
+
+static void armada_3700_soc_pad_voltage_set(struct sdhci_host *host,
+					    unsigned char signal_voltage)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
+	struct xenon_emmc_phy_params *params = priv->phy_params;
+
+	if (params->pad_ctrl.pad_type == SOC_PAD_FIXED_1_8V) {
+		writel(ARMADA_3700_SOC_PAD_1_8V, params->pad_ctrl.reg);
+	} else if (params->pad_ctrl.pad_type == SOC_PAD_SD) {
+		if (signal_voltage == MMC_SIGNAL_VOLTAGE_180)
+			writel(ARMADA_3700_SOC_PAD_1_8V, params->pad_ctrl.reg);
+		else if (signal_voltage == MMC_SIGNAL_VOLTAGE_330)
+			writel(ARMADA_3700_SOC_PAD_3_3V, params->pad_ctrl.reg);
+	}
+}
+
+/*
+ * Set SoC PHY voltage PAD control register,
+ * according to the operation voltage on PAD.
+ * The detailed operation depends on SoC implementation.
+ */
+static void xenon_emmc_phy_set_soc_pad(struct sdhci_host *host,
+				       unsigned char signal_voltage)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
+	struct xenon_emmc_phy_params *params = priv->phy_params;
+
+	if (!params->pad_ctrl.reg)
+		return;
+
+	if (params->pad_ctrl.set_soc_pad)
+		params->pad_ctrl.set_soc_pad(host, signal_voltage);
+}
+
 /*
  * Enable eMMC PHY HW DLL
  * DLL should be enabled and stable before HS200/SDR104 tuning,
@@ -562,6 +618,51 @@ phy_init:
 	dev_dbg(mmc_dev(host->mmc), "eMMC PHY setting completes\n");
 }
 
+static int get_dt_pad_ctrl_data(struct sdhci_host *host,
+				struct device_node *np,
+				struct xenon_emmc_phy_params *params)
+{
+	int ret = 0;
+	const char *name;
+	struct resource iomem;
+
+	if (of_device_is_compatible(np, "marvell,armada-3700-sdhci"))
+		params->pad_ctrl.set_soc_pad = armada_3700_soc_pad_voltage_set;
+	else
+		return 0;
+
+	if (of_address_to_resource(np, 1, &iomem)) {
+		dev_err(mmc_dev(host->mmc), "Unable to find SoC PAD ctrl register address for %s\n",
+			np->name);
+		return -EINVAL;
+	}
+
+	params->pad_ctrl.reg = devm_ioremap_resource(mmc_dev(host->mmc),
+						     &iomem);
+	if (IS_ERR(params->pad_ctrl.reg)) {
+		dev_err(mmc_dev(host->mmc), "Unable to get SoC PHY PAD ctrl register for %s\n",
+			np->name);
+		return PTR_ERR(params->pad_ctrl.reg);
+	}
+
+	ret = of_property_read_string(np, "marvell,pad-type", &name);
+	if (ret) {
+		dev_err(mmc_dev(host->mmc), "Unable to determine SoC PHY PAD ctrl type\n");
+		return ret;
+	}
+	if (!strcmp(name, "sd")) {
+		params->pad_ctrl.pad_type = SOC_PAD_SD;
+	} else if (!strcmp(name, "fixed-1-8v")) {
+		params->pad_ctrl.pad_type = SOC_PAD_FIXED_1_8V;
+	} else {
+		dev_err(mmc_dev(host->mmc), "Unsupported SoC PHY PAD ctrl type %s\n",
+			name);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
 static int xenon_emmc_phy_parse_param_dt(struct sdhci_host *host,
 					 struct device_node *np,
 					 struct xenon_emmc_phy_params *params)
@@ -590,7 +691,14 @@ static int xenon_emmc_phy_parse_param_dt(struct sdhci_host *host,
 				  &value))
 		params->tun_step_divider = value & 0xFF;
 
-	return 0;
+	return get_dt_pad_ctrl_data(host, np, params);
+}
+
+/* Set SoC PHY Voltage PAD */
+void xenon_soc_pad_ctrl(struct sdhci_host *host,
+			unsigned char signal_voltage)
+{
+	xenon_emmc_phy_set_soc_pad(host, signal_voltage);
 }
 
 /*

drivers/mmc/host/sdhci-xenon.c

@@ -280,6 +280,8 @@ static int xenon_start_signal_voltage_switch(struct mmc_host *mmc,
 	 */
 	xenon_enable_internal_clk(host);
 
+	xenon_soc_pad_ctrl(host, ios->signal_voltage);
+
 	/*
 	 * If Vqmmc is fixed on platform, vqmmc regulator should be unavailable.
 	 * Thus SDHCI_CTRL_VDD_180 bit might not work then.

drivers/mmc/host/sdhci-xenon.h

@@ -96,4 +96,6 @@ int xenon_phy_adj(struct sdhci_host *host, struct mmc_ios *ios);
 void xenon_clean_phy(struct sdhci_host *host);
 int xenon_phy_parse_dt(struct device_node *np,
 		       struct sdhci_host *host);
+void xenon_soc_pad_ctrl(struct sdhci_host *host,
+			unsigned char signal_voltage);
 #endif