[PATCH v3 2/2] phy: qualcomm: usb: Add SuperSpeed PHY driver

[Jorge Ramirez-Ortiz]

Controls Qualcomm's SS phy 1.0.0 implemented in the QCS404 and some
other Qualcomm platforms.

Based on Sriharsha Allenki's <sallenki@xxxxxxxxxxxxxx> original code.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@xxxxxxxxxx>
---
 drivers/phy/qualcomm/Kconfig           |  11 +
 drivers/phy/qualcomm/Makefile          |   1 +
 drivers/phy/qualcomm/phy-qcom-usb-ss.c | 328 +++++++++++++++++++++++++
 3 files changed, 340 insertions(+)
 create mode 100644 drivers/phy/qualcomm/phy-qcom-usb-ss.c

diff --git a/drivers/phy/qualcomm/Kconfig b/drivers/phy/qualcomm/Kconfig
index 32f7d34eb784..a8dc550d25fb 100644
--- a/drivers/phy/qualcomm/Kconfig
+++ b/drivers/phy/qualcomm/Kconfig
@@ -82,3 +82,14 @@ config PHY_QCOM_USB_HSIC
 	select GENERIC_PHY
 	help
 	  Support for the USB HSIC ULPI compliant PHY on QCOM chipsets.
+
+config PHY_QCOM_USB_SS
+	tristate "Qualcomm USB SS 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 Qualcomm
+	  chips. This driver supports the PHY which uses the QSCRATCH-based
+	  register set for its control sequences, normally paired with newer
+	  DWC3-based Super-Speed controllers on Qualcomm SoCs.
diff --git a/drivers/phy/qualcomm/Makefile b/drivers/phy/qualcomm/Makefile
index c56efd3af205..d594d532d137 100644
--- a/drivers/phy/qualcomm/Makefile
+++ b/drivers/phy/qualcomm/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_PHY_QCOM_UFS_14NM)		+= phy-qcom-ufs-qmp-14nm.o
 obj-$(CONFIG_PHY_QCOM_UFS_20NM)		+= phy-qcom-ufs-qmp-20nm.o
 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_SS)		+= phy-qcom-usb-ss.o
diff --git a/drivers/phy/qualcomm/phy-qcom-usb-ss.c b/drivers/phy/qualcomm/phy-qcom-usb-ss.c
new file mode 100644
index 000000000000..9e5f4fd9c3a5
--- /dev/null
+++ b/drivers/phy/qualcomm/phy-qcom-usb-ss.c
@@ -0,0 +1,328 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2012-2014,2017 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2018, 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];
+	/* optional vbus regulator */
+	struct vbus_regulator {
+		struct regulator *consumer;
+		bool voted; /* regulator balancing: extcon controlled voltage */
+	} vbus;
+	enum phy_mode mode;
+};
+
+static inline void qcom_ssphy_updatel(void __iomem *addr, u32 mask, u32 val)
+{
+	writel((readl(addr) & ~mask) | val, addr);
+}
+
+static inline int qcom_ssphy_vbus_enable(struct vbus_regulator *vbus)
+{
+	struct regulator *consumer = vbus->consumer;
+	int ret;
+
+	if (vbus->voted || !consumer)
+		return 0;
+
+	ret = regulator_enable(consumer);
+	if (!ret) {
+		/* use count only increments on success */
+		vbus->voted = true;
+	}
+
+	return ret;
+}
+
+static inline int qcom_ssphy_vbus_disable(struct vbus_regulator *vbus)
+{
+	struct regulator *consumer = vbus->consumer;
+
+	if (!vbus->voted || !consumer)
+		return 0;
+
+	vbus->voted = false;
+
+	return regulator_disable(consumer);
+}
+
+static int qcom_ssphy_vbus_ctrl(struct vbus_regulator *vbus, enum phy_mode mode)
+{
+	if (mode == PHY_MODE_INVALID)
+		return 0;
+
+	/* gadget attached */
+	if (mode == PHY_MODE_USB_HOST)
+		return qcom_ssphy_vbus_enable(vbus);
+
+	/* USB_DEVICE: gadget removed: enable detection */
+	return qcom_ssphy_vbus_disable(vbus);
+}
+
+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;
+
+	/* depending on the extcon reported mode, enable or disable vbus */
+	ret = qcom_ssphy_vbus_ctrl(&priv->vbus, priv->mode);
+	if (ret)
+		goto err_disable_clock;
+
+	ret = qcom_ssphy_do_reset(priv);
+	if (ret)
+		goto err_disable_vbus;
+
+	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_vbus:
+	qcom_ssphy_vbus_disable(&priv->vbus);
+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);
+	qcom_ssphy_vbus_disable(&priv->vbus);
+
+	return 0;
+}
+
+static int qcom_ssphy_init_clock(struct ssphy_priv *priv)
+{
+	priv->clks[0].id = "ref";
+	priv->clks[1].id = "phy";
+	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)
+		return ret;
+
+	priv->vbus.voted = false;
+	priv->vbus.consumer = devm_regulator_get_optional(priv->dev, "vbus");
+	if (IS_ERR(priv->vbus.consumer)) {
+		if (PTR_ERR(priv->vbus.consumer) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+
+		/* regulator_get_optional does not return NULL if not found */
+		priv->vbus.consumer = NULL;
+	}
+
+	return 0;
+}
+
+static int qcom_ssphy_init_reset(struct ssphy_priv *priv)
+{
+	priv->reset_com = devm_reset_control_get_optional(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(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 int qcom_ssphy_set_mode(struct phy *phy, enum phy_mode mode, int submode)
+{
+	struct ssphy_priv *priv = phy_get_drvdata(phy);
+
+	if (!priv->vbus.consumer)
+		return 0;
+
+	if (mode != PHY_MODE_USB_HOST && mode != PHY_MODE_USB_DEVICE)
+		return -EINVAL;
+
+	priv->mode = mode;
+	dev_dbg(priv->dev, "mode %d", mode);
+
+	return qcom_ssphy_vbus_ctrl(&priv->vbus, priv->mode);
+}
+
+static const struct phy_ops qcom_ssphy_ops = {
+	.set_mode = qcom_ssphy_set_mode,
+	.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 resource *res;
+	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;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->base = devm_ioremap_resource(dev, res);
+	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-ssphy", },
+	{ },
+};
+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");
-- 
2.20.1