[PATCH 2/2] drivers: usb: dwc3: Add AM62 USB wrapper driver

[Aswath Govindraju]

In AM62 SoC, the Designware Core USB3 IP is progammed to operate in USB2.0
only mode. The ID pin and VBUS state changes are detected in the
wrapper and the role is indicated to the dwc3 core driver using extcon.
Therefore, add driver for AM62 USB DWC3 Wrapper driver.

Signed-off-by: Aswath Govindraju <a-govindraju@xxxxxx>
---
 drivers/usb/dwc3/Kconfig     |   9 +
 drivers/usb/dwc3/Makefile    |   1 +
 drivers/usb/dwc3/dwc3-am62.c | 577 +++++++++++++++++++++++++++++++++++
 3 files changed, 587 insertions(+)
 create mode 100644 drivers/usb/dwc3/dwc3-am62.c

diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index c483f28b695d..cd9a734522a7 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -159,4 +159,13 @@ config USB_DWC3_XILINX
 	  This driver handles both ZynqMP and Versal SoC operations.
 	  Say 'Y' or 'M' if you have one such device.
 
+config USB_DWC3_AM62
+	tristate "Texas Instruments AM62 Platforms"
+	depends on ARCH_K3 || COMPILE_TEST
+	default USB_DWC3
+	help
+	  Support TI's AM62 platforms with DesignWare Core USB3 IP.
+	  The Designware Core USB3 IP is progammed to operate in
+	  in USB 2.0 mode only.
+	  Say 'Y' or 'M' here if you have one such device
 endif
diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
index 2d499de6f66a..9f66bd82b639 100644
--- a/drivers/usb/dwc3/Makefile
+++ b/drivers/usb/dwc3/Makefile
@@ -42,6 +42,7 @@ endif
 # and allyesconfig builds.
 ##
 
+obj-$(CONFIG_USB_DWC3_AM62)		+= dwc3-am62.o
 obj-$(CONFIG_USB_DWC3_OMAP)		+= dwc3-omap.o
 obj-$(CONFIG_USB_DWC3_EXYNOS)		+= dwc3-exynos.o
 obj-$(CONFIG_USB_DWC3_PCI)		+= dwc3-pci.o
diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
new file mode 100644
index 000000000000..c5e5cb37a321
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3-am62.c
@@ -0,0 +1,577 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * dwc3-am62.c - TI specific Glue layer for AM62 DWC3 USB Controller
+ *
+ * Copyright (C) 2022 Texas Instruments Incorporated - https://www.ti.com
+ */
+
+#include <linux/extcon-provider.h>
+#include <linux/gpio/consumer.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/extcon.h>
+#include <linux/workqueue.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/clk.h>
+#include <linux/regmap.h>
+#include <linux/devm-helpers.h>
+#include <linux/pinctrl/consumer.h>
+
+/* USB WRAPPER register offsets */
+#define USBSS_PID			0x0
+#define USBSS_OVERCURRENT_CTRL		0x4
+#define USBSS_PHY_CONFIG		0x8
+#define USBSS_PHY_TEST			0xc
+#define USBSS_CORE_STAT			0x14
+#define USBSS_HOST_VBUS_CTRL		0x18
+#define USBSS_MODE_CONTROL		0x1c
+#define USBSS_WAKEUP_CONFIG		0x30
+#define USBSS_WAKEUP_STAT		0x34
+#define USBSS_OVERRIDE_CONFIG		0x38
+#define USBSS_IRQ_MISC_STATUS_RAW	0x430
+#define USBSS_IRQ_MISC_STATUS		0x434
+#define USBSS_IRQ_MISC_ENABLE_SET	0x438
+#define USBSS_IRQ_MISC_ENABLE_CLR	0x43c
+#define USBSS_IRQ_MISC_EOI		0x440
+#define USBSS_INTR_TEST			0x490
+#define USBSS_VBUS_FILTER		0x614
+#define USBSS_VBUS_STAT			0x618
+#define USBSS_DEBUG_CFG			0x708
+#define USBSS_DEBUG_DATA		0x70c
+#define USBSS_HOST_HUB_CTRL		0x714
+
+/* PHY CONFIG register bits */
+#define USBSS_PHY_VBUS_SEL_MASK		GENMASK(2, 1)
+#define USBSS_PHY_VBUS_SEL_SHIFT	1
+#define USBSS_PHY_LANE_REVERSE		BIT(0)
+
+/* MODE CONTROL register bits */
+#define USBSS_MODE_VALID	BIT(0)
+
+/* WAKEUP CONFIG register bits */
+#define USBSS_WAKEUP_CFG_OVERCURRENT_EN	BIT(3)
+#define USBSS_WAKEUP_CFG_LINESTATE_EN	BIT(2)
+#define USBSS_WAKEUP_CFG_SESSVALID_EN	BIT(1)
+#define USBSS_WAKEUP_CFG_VBUSVALID_EN	BIT(0)
+
+/* WAKEUP STAT register bits */
+#define USBSS_WAKEUP_STAT_OVERCURRENT	BIT(4)
+#define USBSS_WAKEUP_STAT_LINESTATE	BIT(3)
+#define USBSS_WAKEUP_STAT_SESSVALID	BIT(2)
+#define USBSS_WAKEUP_STAT_VBUSVALID	BIT(1)
+#define USBSS_WAKEUP_STAT_CLR		BIT(0)
+
+/* IRQ_MISC_STATUS_RAW register bits */
+#define USBSS_IRQ_MISC_RAW_VBUSVALID	BIT(22)
+#define USBSS_IRQ_MISC_RAW_SESSVALID	BIT(20)
+
+/* IRQ_MISC_STATUS register bits */
+#define USBSS_IRQ_MISC_VBUSVALID	BIT(22)
+#define USBSS_IRQ_MISC_SESSVALID	BIT(20)
+
+/* IRQ_MISC_ENABLE_SET register bits */
+#define USBSS_IRQ_MISC_ENABLE_SET_VBUSVALID	BIT(22)
+#define USBSS_IRQ_MISC_ENABLE_SET_SESSVALID	BIT(20)
+
+/* IRQ_MISC_ENABLE_CLR register bits */
+#define USBSS_IRQ_MISC_ENABLE_CLR_VBUSVALID	BIT(22)
+#define USBSS_IRQ_MISC_ENABLE_CLR_SESSVALID	BIT(20)
+
+/* IRQ_MISC_EOI register bits */
+#define USBSS_IRQ_MISC_EOI_VECTOR	BIT(0)
+
+/* VBUS_STAT register bits */
+#define USBSS_VBUS_STAT_SESSVALID	BIT(2)
+#define USBSS_VBUS_STAT_VBUSVALID	BIT(0)
+
+/* Mask for PHY PLL REFCLK */
+#define PHY_PLL_REFCLK_MASK	GENMASK(3, 0)
+
+#define DWC3_AM62_AUTOSUSPEND_DELAY	100
+
+enum role {
+	DEVICE,
+	HOST,
+};
+
+struct id_gpio_data {
+	struct gpio_desc *gpiod;
+	int id_irq;
+};
+
+struct dwc3_data {
+	struct device *dev;
+	void __iomem *usbss;
+	struct clk *usb2_refclk;
+	struct extcon_dev *edev;
+	unsigned int extcon_id;
+	struct id_gpio_data *id_gpio;
+	struct work_struct work;
+	int vbus_irq;
+	int rate_code;
+	enum role current_role;
+	int connect;
+	struct regmap *syscon;
+	unsigned int offset;
+	unsigned int vbus_divider;
+};
+
+static const int dwc3_ti_rate_table[] = {	/* in KHZ */
+	9600,
+	10000,
+	12000,
+	19200,
+	20000,
+	24000,
+	25000,
+	26000,
+	38400,
+	40000,
+	58000,
+	50000,
+	52000,
+};
+
+static const unsigned int usb_extcon_cable[] = {
+	EXTCON_USB,
+	EXTCON_USB_HOST,
+};
+
+static inline u32 dwc3_ti_readl(struct dwc3_data *data, u32 offset)
+{
+	return readl((data->usbss) + offset);
+}
+
+static inline void dwc3_ti_writel(struct dwc3_data *data, u32 offset, u32 value)
+{
+	writel(value, (data->usbss) + offset);
+}
+
+static void role_detect_work(struct work_struct *work)
+{
+	struct dwc3_data *data =
+		container_of(work, struct dwc3_data, work);
+	u32 vbus_state, reg;
+	int id_state = 0;
+	enum role detect_role;
+	int connect = 0;
+
+	/* Read the status for VBUS valid register */
+	vbus_state = dwc3_ti_readl(data, USBSS_VBUS_STAT);
+	vbus_state = vbus_state & USBSS_VBUS_STAT_VBUSVALID;
+
+	/* Read the status of ID GPIO */
+	if (data->id_gpio)
+		id_state = gpiod_get_value_cansleep(data->id_gpio->gpiod);
+
+	/*
+	 * ID | VBUS | STATE
+	 * -----------------
+	 * 0  | 0    | HOST
+	 * 0  | 1    | HOST
+	 * 1  | 0    | Disconnected (set mode valid to 0)
+	 * 1  | 1    | Device
+	 *
+	 */
+	/* detemine the role or find out if disconnect event */
+	if (id_state) {
+		detect_role = DEVICE;
+		if (vbus_state)
+			connect = 1;
+	} else {
+		detect_role = HOST;
+		connect = 1;
+	}
+
+	/* Set or clear mode valid bit based on connect or disconnect event */
+	if (data->connect != connect) {
+		reg = dwc3_ti_readl(data, USBSS_MODE_CONTROL);
+		if (connect)
+			reg |= USBSS_MODE_VALID;
+		else
+			reg &= ~USBSS_MODE_VALID;
+
+		dwc3_ti_writel(data, USBSS_MODE_CONTROL, reg);
+		data->connect = connect;
+	}
+
+	/* Send extcon sync signal to the dwc3 controller driver */
+	if (data->current_role != detect_role) {
+		if (detect_role == HOST)
+			extcon_set_state_sync(data->edev, EXTCON_USB_HOST, true);
+		else
+			extcon_set_state_sync(data->edev, EXTCON_USB_HOST, false);
+
+		data->current_role = detect_role;
+	}
+}
+
+static irqreturn_t role_detect_irq_handler(int irq, void *dev_id)
+{
+	struct dwc3_data *data = dev_id;
+	u32 reg;
+
+	/* Clear VBUS interrupt always to aviod queuing up redundant work items */
+	reg = dwc3_ti_readl(data, USBSS_IRQ_MISC_STATUS);
+	reg |= USBSS_IRQ_MISC_VBUSVALID;
+	dwc3_ti_writel(data, USBSS_IRQ_MISC_STATUS, reg);
+
+	queue_work(system_power_efficient_wq, &data->work);
+
+	reg = dwc3_ti_readl(data, USBSS_IRQ_MISC_EOI);
+	reg &= ~USBSS_IRQ_MISC_EOI_VECTOR;
+	dwc3_ti_writel(data, USBSS_IRQ_MISC_EOI, reg);
+	return IRQ_HANDLED;
+}
+
+static int dwc3_ti_vbus_irq_setup(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct dwc3_data *data = platform_get_drvdata(pdev);
+	int irq, ret;
+
+	/* Get the misc interrupt */
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	ret = devm_request_irq(dev, irq, role_detect_irq_handler, IRQF_SHARED,
+			       dev_name(dev), data);
+	if (ret) {
+		dev_err(dev, "failed to required IRQ #%d-->%d\n",
+			irq, ret);
+		return ret;
+	}
+
+	data->vbus_irq = irq;
+
+	return 0;
+}
+
+/* Allocate the memory and register the extcon device */
+static int dwc3_ti_register_extcon(struct dwc3_data *data)
+{
+	int ret;
+
+	data->edev = devm_extcon_dev_allocate(data->dev, usb_extcon_cable);
+	if (IS_ERR(data->edev)) {
+		dev_err(data->dev, "failed to allocate extcon device\n");
+		return -ENOMEM;
+	}
+
+	ret = devm_extcon_dev_register(data->dev, data->edev);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int dwc3_ti_get_id_gpio(struct dwc3_data *data)
+{
+	struct id_gpio_data *id_gpio;
+	struct device	*dev = data->dev;
+	unsigned long irq_flags;
+	int irq, ret;
+
+	/* create the extcon device */
+	id_gpio = devm_kzalloc(dev, sizeof(struct id_gpio_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	/* Read id-gpio property */
+	id_gpio->gpiod = devm_gpiod_get_optional(dev, "id", GPIOD_IN);
+	if (IS_ERR(id_gpio->gpiod))
+		return PTR_ERR(id_gpio->gpiod);
+
+	/* If id-gpio property is not present */
+	if (!id_gpio->gpiod)
+		return 0;
+
+	irq = gpiod_to_irq(id_gpio->gpiod);
+	if (irq <= 0)
+		return irq;
+	id_gpio->id_irq = irq;
+
+	/* SET irq flags
+	 * Use both edges for detecting connect and disconnect events
+	 */
+	irq_flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING;
+
+	ret = devm_request_any_context_irq(dev, irq,
+					   role_detect_irq_handler, irq_flags,
+					   "id_gpio", data);
+	if (ret < 0)
+		return ret;
+
+	/* To be enabled only after probing dwc3 core */
+	disable_irq(irq);
+	data->id_gpio = id_gpio;
+	return 0;
+}
+
+static int phy_syscon_pll_refclk(struct dwc3_data *data)
+{
+	struct device *dev = data->dev;
+	struct device_node *node = dev->of_node;
+	struct of_phandle_args args;
+	struct regmap *syscon;
+	int ret;
+
+	syscon = syscon_regmap_lookup_by_phandle(node, "ti,syscon-phy-pll-refclk");
+	if (IS_ERR(syscon)) {
+		dev_err(dev, "unable to get ti,syscon-phy-pll-refclk regmap\n");
+		return PTR_ERR(syscon);
+	}
+
+	data->syscon = syscon;
+
+	ret = of_parse_phandle_with_fixed_args(node, "ti,syscon-phy-pll-refclk", 1,
+					       0, &args);
+	if (ret)
+		return ret;
+
+	data->offset = args.args[0];
+
+	ret = regmap_update_bits(data->syscon, data->offset, PHY_PLL_REFCLK_MASK, data->rate_code);
+	if (ret) {
+		dev_err(dev, "failed to set phy pll reference clock rate\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static void dwc3_ti_enable_irqs(struct dwc3_data *data)
+{
+	u32 reg;
+
+	/* enable VBUSVALID interrupt */
+	reg = dwc3_ti_readl(data, USBSS_IRQ_MISC_ENABLE_SET);
+	reg |= USBSS_IRQ_MISC_ENABLE_SET_VBUSVALID;
+	dwc3_ti_writel(data, USBSS_IRQ_MISC_ENABLE_SET, reg);
+
+	/* enable id-gpio interrupt */
+	if (data->id_gpio)
+		enable_irq(data->id_gpio->id_irq);
+}
+
+static void dwc3_ti_disable_irqs(struct dwc3_data *data)
+{
+	u32 reg;
+
+	/* disable VBUSVALID interrupt */
+	reg = dwc3_ti_readl(data, USBSS_IRQ_MISC_ENABLE_CLR);
+	reg |= USBSS_IRQ_MISC_ENABLE_CLR_VBUSVALID;
+	dwc3_ti_writel(data, USBSS_IRQ_MISC_ENABLE_CLR, reg);
+
+	/* disable id-gpio interrupt */
+	if (data->id_gpio)
+		disable_irq(data->id_gpio->id_irq);
+}
+
+static int dwc3_ti_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *node = pdev->dev.of_node;
+	struct dwc3_data *data;
+	int i, ret;
+	unsigned long rate;
+	u32 reg;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->dev = dev;
+	platform_set_drvdata(pdev, data);
+
+	data->usbss = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(data->usbss)) {
+		dev_err(dev, "can't map IOMEM resource\n");
+		return PTR_ERR(data->usbss);
+	}
+
+	data->usb2_refclk = devm_clk_get(dev, "ref");
+	if (IS_ERR(data->usb2_refclk)) {
+		dev_err(dev, "can't get usb2_refclk\n");
+		return PTR_ERR(data->usb2_refclk);
+	}
+
+	/*Calculate the rate code */
+	rate = clk_get_rate(data->usb2_refclk);
+	rate /= 1000;	// To KHz
+	for (i = 0; i < ARRAY_SIZE(dwc3_ti_rate_table); i++) {
+		if (dwc3_ti_rate_table[i] == rate)
+			break;
+	}
+
+	if (i == ARRAY_SIZE(dwc3_ti_rate_table)) {
+		dev_err(dev, "unsupported usb2_refclk rate: %lu KHz\n", rate);
+		ret = -EINVAL;
+		goto err_clk_disable;
+	}
+
+	data->rate_code = i;
+
+	/* Read the syscon property and set the rate code */
+	ret = phy_syscon_pll_refclk(data);
+	if (ret)
+		goto err_clk_disable;
+
+	/* VBUS divider select */
+	data->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
+	reg = dwc3_ti_readl(data, USBSS_PHY_CONFIG);
+	if (data->vbus_divider)
+		reg |= 1 << USBSS_PHY_VBUS_SEL_SHIFT;
+
+	dwc3_ti_writel(data, USBSS_PHY_CONFIG, reg);
+
+	/* Register as an extcon device */
+	ret = dwc3_ti_register_extcon(data);
+	if (ret)
+		goto err_clk_disable;
+
+	/* Initialize a work queue */
+	ret = devm_work_autocancel(dev, &data->work, role_detect_work);
+	if (ret)
+		goto err_clk_disable;
+
+	/* Get struct gpio and irq for ID pin */
+	ret = dwc3_ti_get_id_gpio(data);
+	if (ret) {
+		dev_err(dev, "error reading id-gpio property");
+		goto err_clk_disable;
+	}
+
+	/* Read and set VBUS IRQ */
+	ret = dwc3_ti_vbus_irq_setup(pdev);
+	if (ret)
+		goto err_clk_disable;
+
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+	/*
+	 * Don't ignore its dependencies with its children
+	 */
+	pm_suspend_ignore_children(dev, false);
+	clk_prepare_enable(data->usb2_refclk);
+	pm_runtime_get_noresume(dev);
+
+	ret = of_platform_populate(node, NULL, NULL, dev);
+	if (ret) {
+		dev_err(dev, "failed to create dwc3 core: %d\n", ret);
+		goto err_pm_disable;
+	}
+
+	/* Enable gpio and vbus irqs */
+	dwc3_ti_enable_irqs(data);
+
+	role_detect_work(&data->work);
+
+	/* Setting up autosuspend */
+	pm_runtime_set_autosuspend_delay(dev, DWC3_AM62_AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+	return 0;
+
+err_pm_disable:
+	clk_disable_unprepare(data->usb2_refclk);
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+err_clk_disable:
+	clk_put(data->usb2_refclk);
+	return ret;
+}
+
+static int dwc3_ti_remove_core(struct device *dev, void *c)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+
+	platform_device_unregister(pdev);
+	return 0;
+}
+
+static int dwc3_ti_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct dwc3_data *data = platform_get_drvdata(pdev);
+	u32 reg;
+
+	dwc3_ti_disable_irqs(data);
+
+	device_for_each_child(dev, NULL, dwc3_ti_remove_core);
+
+	/* Clear mode valid bit */
+	reg = dwc3_ti_readl(data, USBSS_MODE_CONTROL);
+	reg &= ~USBSS_MODE_VALID;
+	dwc3_ti_writel(data, USBSS_MODE_CONTROL, reg);
+
+	pm_runtime_put_sync(dev);
+	clk_disable_unprepare(data->usb2_refclk);
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+
+	clk_put(data->usb2_refclk);
+	platform_set_drvdata(pdev, NULL);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int dwc3_ti_suspend_common(struct device *dev)
+{
+	struct dwc3_data *data = dev_get_drvdata(dev);
+
+	/* disable irqs */
+	dwc3_ti_disable_irqs(data);
+
+	clk_disable_unprepare(data->usb2_refclk);
+
+	return 0;
+}
+
+static int dwc3_ti_resume_common(struct device *dev)
+{
+	struct dwc3_data *data = dev_get_drvdata(dev);
+
+	clk_prepare_enable(data->usb2_refclk);
+
+	/* Enable irqs */
+	dwc3_ti_enable_irqs(data);
+
+	return 0;
+}
+
+static UNIVERSAL_DEV_PM_OPS(dwc3_ti_pm_ops, dwc3_ti_suspend_common,
+			    dwc3_ti_resume_common, NULL);
+#endif
+
+static const struct of_device_id dwc3_ti_of_match[] = {
+	{ .compatible = "ti,am62-usb"},
+	{},
+};
+MODULE_DEVICE_TABLE(of, dwc3_ti_of_match);
+
+static struct platform_driver dwc3_ti_driver = {
+	.probe		= dwc3_ti_probe,
+	.remove		= dwc3_ti_remove,
+	.driver		= {
+		.name	= "dwc3-am62",
+		.pm	= &dwc3_ti_pm_ops,
+		.of_match_table = dwc3_ti_of_match,
+	},
+};
+
+module_platform_driver(dwc3_ti_driver);
+
+MODULE_ALIAS("platform:dwc3-am62");
+MODULE_AUTHOR("Aswath Govindraju <a-govindraju@xxxxxx>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("DesignWare USB3 TI Glue Layer");
-- 
2.17.1