Date:   Wed, 6 Apr 2022 19:22:11 +0530
From:   Aswath Govindraju <a-govindraju@...com>
To:     unlisted-recipients:; (no To-header on input)
CC:     Vignesh Raghavendra <vigneshr@...com>,
        Kishon Vijay Abraham I <kishon@...com>,
        Aswath Govindraju <a-govindraju@...com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Felipe Balbi <balbi@...nel.org>, <linux-usb@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v3 2/2] drivers: usb: dwc3: Add AM62 USB wrapper driver

In AM62 SoC, the Designware Core USB3 IP is progammed to operate in USB2.0
only mode. Add driver for AM62 USB DWC3 Wrapper.

Signed-off-by: Aswath Govindraju <a-govindraju@...com>
---

changes since v2:
- Removed the implementation of detecting the role from the wrapper
  driver and moved the implementation to using linux,extcon-usb-gpio
  driver for role detection.
- Updated the binding documentation and example to reflect the same.


 drivers/usb/dwc3/Kconfig     |   9 +
 drivers/usb/dwc3/Makefile    |   1 +
 drivers/usb/dwc3/dwc3-am62.c | 446 +++++++++++++++++++++++++++++++++++
 3 files changed, 456 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..5700258c8deb
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3-am62.c
@@ -0,0 +1,446 @@
+// 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/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/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
+
+struct dwc3_data {
+	struct device *dev;
+	void __iomem *usbss;
+	struct clk *usb2_refclk;
+	struct work_struct work;
+	int vbus_irq;
+	int rate_code;
+	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 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 connect_detect_work(struct work_struct *work)
+{
+	struct dwc3_data *data =
+		container_of(work, struct dwc3_data, work);
+	u32 vbus_state, reg;
+	int connect = 0;
+
+	/* Read the status for VBUS valid register */
+	vbus_state = dwc3_ti_readl(data, USBSS_VBUS_STAT);
+	vbus_state &= USBSS_VBUS_STAT_VBUSVALID;
+
+	if (vbus_state)
+		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;
+	}
+}
+
+static irqreturn_t connect_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, connect_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;
+}
+
+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);
+}
+
+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);
+}
+
+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);
+
+	/* Initialize a work queue */
+	ret = devm_work_autocancel(dev, &data->work, connect_detect_work);
+	if (ret)
+		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 vbus irq */
+	dwc3_ti_enable_irqs(data);
+
+	connect_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);
+
+#define DEV_PM_OPS	(&dwc3_ti_pm_ops)
+#else
+#define DEV_PM_OPS	NULL
+#endif /* CONFIG_PM */
+
+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	= DEV_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@...com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("DesignWare USB3 TI Glue Layer");
-- 
2.17.1

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