phy: qualcomm: usb: Add SuperSpeed PHY driver

Controls Qualcomm's SS PHY 1.0.0 implemented on various SoCs on both the
20nm and 28nm process nodes.

Based on Sriharsha Allenki's <[e-mail]> original code.

[bod: Removed dependency on extcon.
Switched to gpio-usb-conn to handle VBUS On/Off
Switched to usb-role-switch to bind gpio-usb-conn to DWC3]
Signed-off-by: Jorge Ramirez-Ortiz <[e-mail]>
Cc: Jorge Ramirez-Ortiz <[e-mail]>
Cc: Sriharsha Allenki's <[e-mail]>
Cc: Andy Gross <[e-mail]>
Cc: Bjorn Andersson <[e-mail]>
Cc: Kishon Vijay Abraham I <[e-mail]>
Cc: Philipp Zabel <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Reviewed-by: Philipp Zabel <[e-mail]>
Tested-by: Bjorn Andersson <[e-mail]>
Signed-off-by: Bryan O'Donoghue <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

drivers/phy/qualcomm/Kconfig

···
 	  High-Speed PHY driver. This driver supports the Hi-Speed PHY which
 	  is usually paired with either the ChipIdea or Synopsys DWC3 USB
 	  IPs on MSM SOCs.
+
+config PHY_QCOM_USB_SS
+	tristate "Qualcomm USB Super-Speed PHY driver"
+	depends on ARCH_QCOM || COMPILE_TEST
+	depends on EXTCON || !EXTCON # if EXTCON=m, this cannot be built-in
+	select GENERIC_PHY
+	help
+	  Enable this to support the Super-Speed USB transceiver on various
+	  Qualcomm chipsets.

drivers/phy/qualcomm/Makefile

···
 obj-$(CONFIG_PHY_QCOM_USB_HS) 		+= phy-qcom-usb-hs.o
 obj-$(CONFIG_PHY_QCOM_USB_HSIC) 	+= phy-qcom-usb-hsic.o
 obj-$(CONFIG_PHY_QCOM_USB_HS_28NM)	+= phy-qcom-usb-hs-28nm.o
+obj-$(CONFIG_PHY_QCOM_USB_SS)		+= phy-qcom-usb-ss.o

drivers/phy/qualcomm/phy-qcom-usb-ss.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2012-2014,2017 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2018-2020, Linaro Limited
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#define PHY_CTRL0			0x6C
+#define PHY_CTRL1			0x70
+#define PHY_CTRL2			0x74
+#define PHY_CTRL4			0x7C
+
+/* PHY_CTRL bits */
+#define REF_PHY_EN			BIT(0)
+#define LANE0_PWR_ON			BIT(2)
+#define SWI_PCS_CLK_SEL			BIT(4)
+#define TST_PWR_DOWN			BIT(4)
+#define PHY_RESET			BIT(7)
+
+#define NUM_BULK_CLKS			3
+#define NUM_BULK_REGS			2
+
+struct ssphy_priv {
+	void __iomem *base;
+	struct device *dev;
+	struct reset_control *reset_com;
+	struct reset_control *reset_phy;
+	struct regulator_bulk_data regs[NUM_BULK_REGS];
+	struct clk_bulk_data clks[NUM_BULK_CLKS];
+	enum phy_mode mode;
+};
+
+static inline void qcom_ssphy_updatel(void __iomem *addr, u32 mask, u32 val)
+{
+	writel((readl(addr) & ~mask) | val, addr);
+}
+
+static int qcom_ssphy_do_reset(struct ssphy_priv *priv)
+{
+	int ret;
+
+	if (!priv->reset_com) {
+		qcom_ssphy_updatel(priv->base + PHY_CTRL1, PHY_RESET,
+				   PHY_RESET);
+		usleep_range(10, 20);
+		qcom_ssphy_updatel(priv->base + PHY_CTRL1, PHY_RESET, 0);
+	} else {
+		ret = reset_control_assert(priv->reset_com);
+		if (ret) {
+			dev_err(priv->dev, "Failed to assert reset com\n");
+			return ret;
+		}
+
+		ret = reset_control_assert(priv->reset_phy);
+		if (ret) {
+			dev_err(priv->dev, "Failed to assert reset phy\n");
+			return ret;
+		}
+
+		usleep_range(10, 20);
+
+		ret = reset_control_deassert(priv->reset_com);
+		if (ret) {
+			dev_err(priv->dev, "Failed to deassert reset com\n");
+			return ret;
+		}
+
+		ret = reset_control_deassert(priv->reset_phy);
+		if (ret) {
+			dev_err(priv->dev, "Failed to deassert reset phy\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int qcom_ssphy_power_on(struct phy *phy)
+{
+	struct ssphy_priv *priv = phy_get_drvdata(phy);
+	int ret;
+
+	ret = regulator_bulk_enable(NUM_BULK_REGS, priv->regs);
+	if (ret)
+		return ret;
+
+	ret = clk_bulk_prepare_enable(NUM_BULK_CLKS, priv->clks);
+	if (ret)
+		goto err_disable_regulator;
+
+	ret = qcom_ssphy_do_reset(priv);
+	if (ret)
+		goto err_disable_clock;
+
+	writeb(SWI_PCS_CLK_SEL, priv->base + PHY_CTRL0);
+	qcom_ssphy_updatel(priv->base + PHY_CTRL4, LANE0_PWR_ON, LANE0_PWR_ON);
+	qcom_ssphy_updatel(priv->base + PHY_CTRL2, REF_PHY_EN, REF_PHY_EN);
+	qcom_ssphy_updatel(priv->base + PHY_CTRL4, TST_PWR_DOWN, 0);
+
+	return 0;
+err_disable_clock:
+	clk_bulk_disable_unprepare(NUM_BULK_CLKS, priv->clks);
+err_disable_regulator:
+	regulator_bulk_disable(NUM_BULK_REGS, priv->regs);
+
+	return ret;
+}
+
+static int qcom_ssphy_power_off(struct phy *phy)
+{
+	struct ssphy_priv *priv = phy_get_drvdata(phy);
+
+	qcom_ssphy_updatel(priv->base + PHY_CTRL4, LANE0_PWR_ON, 0);
+	qcom_ssphy_updatel(priv->base + PHY_CTRL2, REF_PHY_EN, 0);
+	qcom_ssphy_updatel(priv->base + PHY_CTRL4, TST_PWR_DOWN, TST_PWR_DOWN);
+
+	clk_bulk_disable_unprepare(NUM_BULK_CLKS, priv->clks);
+	regulator_bulk_disable(NUM_BULK_REGS, priv->regs);
+
+	return 0;
+}
+
+static int qcom_ssphy_init_clock(struct ssphy_priv *priv)
+{
+	priv->clks[0].id = "ref";
+	priv->clks[1].id = "ahb";
+	priv->clks[2].id = "pipe";
+
+	return devm_clk_bulk_get(priv->dev, NUM_BULK_CLKS, priv->clks);
+}
+
+static int qcom_ssphy_init_regulator(struct ssphy_priv *priv)
+{
+	int ret;
+
+	priv->regs[0].supply = "vdd";
+	priv->regs[1].supply = "vdda1p8";
+	ret = devm_regulator_bulk_get(priv->dev, NUM_BULK_REGS, priv->regs);
+	if (ret) {
+		if (ret != -EPROBE_DEFER)
+			dev_err(priv->dev, "Failed to get regulators\n");
+		return ret;
+	}
+
+	return ret;
+}
+
+static int qcom_ssphy_init_reset(struct ssphy_priv *priv)
+{
+	priv->reset_com = devm_reset_control_get_optional_exclusive(priv->dev, "com");
+	if (IS_ERR(priv->reset_com)) {
+		dev_err(priv->dev, "Failed to get reset control com\n");
+		return PTR_ERR(priv->reset_com);
+	}
+
+	if (priv->reset_com) {
+		/* if reset_com is present, reset_phy is no longer optional */
+		priv->reset_phy = devm_reset_control_get_exclusive(priv->dev, "phy");
+		if (IS_ERR(priv->reset_phy)) {
+			dev_err(priv->dev, "Failed to get reset control phy\n");
+			return PTR_ERR(priv->reset_phy);
+		}
+	}
+
+	return 0;
+}
+
+static const struct phy_ops qcom_ssphy_ops = {
+	.power_off = qcom_ssphy_power_off,
+	.power_on = qcom_ssphy_power_on,
+	.owner = THIS_MODULE,
+};
+
+static int qcom_ssphy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct phy_provider *provider;
+	struct ssphy_priv *priv;
+	struct phy *phy;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(struct ssphy_priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+	priv->mode = PHY_MODE_INVALID;
+
+	priv->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	ret = qcom_ssphy_init_clock(priv);
+	if (ret)
+		return ret;
+
+	ret = qcom_ssphy_init_reset(priv);
+	if (ret)
+		return ret;
+
+	ret = qcom_ssphy_init_regulator(priv);
+	if (ret)
+		return ret;
+
+	phy = devm_phy_create(dev, dev->of_node, &qcom_ssphy_ops);
+	if (IS_ERR(phy)) {
+		dev_err(dev, "Failed to create the SS phy\n");
+		return PTR_ERR(phy);
+	}
+
+	phy_set_drvdata(phy, priv);
+
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(provider);
+}
+
+static const struct of_device_id qcom_ssphy_match[] = {
+	{ .compatible = "qcom,usb-ss-28nm-phy", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, qcom_ssphy_match);
+
+static struct platform_driver qcom_ssphy_driver = {
+	.probe		= qcom_ssphy_probe,
+	.driver = {
+		.name	= "qcom-usb-ssphy",
+		.of_match_table = qcom_ssphy_match,
+	},
+};
+module_platform_driver(qcom_ssphy_driver);
+
+MODULE_DESCRIPTION("Qualcomm SuperSpeed USB PHY driver");
+MODULE_LICENSE("GPL v2");