[V2,5/8] soc: qcom: eud: Add driver support for Embedded USB Debugger(EUD)

diff --git a/Documentation/ABI/testing/sysfs-driver-eud b/Documentation/ABI/testing/sysfs-driver-eud
new file mode 100644
index 0000000..eaf2e82
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-eud
@@ -0,0 +1,9 @@ 
+What:		/sys/bus/platform/drivers/eud/.../enable
+Date:           October 2021
+Contact:        Souradeep Chowdhury <quic_schowdhu@quicinc.com>
+Description:
+		The Enable/Disable sysfs interface for Embedded
+		USB Debugger(EUD). This enables and disables the
+		EUD based on a 1 or a 0 value. By enabling EUD,
+		the user is able to activate the mini-usb hub of
+		EUD for debug and trace capabilities.
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 79b568f..a4db41b 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -42,6 +42,16 @@  config QCOM_CPR
 	  To compile this driver as a module, choose M here: the module will
 	  be called qcom-cpr

+config QCOM_EUD
+	tristate "QCOM Embedded USB Debugger(EUD) Driver"
+	select USB_ROLE_SWITCH
+	help
+	  This module enables support for Qualcomm Technologies, Inc.
+	  Embedded USB Debugger (EUD). The EUD is a control peripheral
+	  which reports VBUS attach/detach events and has USB-based
+	  debug and trace capabilities. On selecting m, the module name
+	  that is built is qcom_eud.ko
+
 config QCOM_GENI_SE
 	tristate "QCOM GENI Serial Engine Driver"
 	depends on ARCH_QCOM || COMPILE_TEST
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index ad675a6..3331a40 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -4,6 +4,7 @@  obj-$(CONFIG_QCOM_AOSS_QMP) +=	qcom_aoss.o
 obj-$(CONFIG_QCOM_GENI_SE) +=	qcom-geni-se.o
 obj-$(CONFIG_QCOM_COMMAND_DB) += cmd-db.o
 obj-$(CONFIG_QCOM_CPR)		+= cpr.o
+obj-$(CONFIG_QCOM_EUD)          += qcom_eud.o
 obj-$(CONFIG_QCOM_GSBI)	+=	qcom_gsbi.o
 obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
 obj-$(CONFIG_QCOM_OCMEM)	+= ocmem.o
diff --git a/drivers/soc/qcom/qcom_eud.c b/drivers/soc/qcom/qcom_eud.c
new file mode 100644
index 0000000..613ac41
--- /dev/null
+++ b/drivers/soc/qcom/qcom_eud.c
@@ -0,0 +1,268 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2015-2021, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/usb/role.h>
+
+#define EUD_REG_INT1_EN_MASK	0x0024
+#define EUD_REG_INT_STATUS_1	0x0044
+#define EUD_REG_CTL_OUT_1	0x0074
+#define EUD_REG_VBUS_INT_CLR	0x0080
+#define EUD_REG_CSR_EUD_EN	0x1014
+#define EUD_REG_SW_ATTACH_DET	0x1018
+#define EUD_REG_EUD_EN2         0x0000
+
+#define EUD_ENABLE		BIT(0)
+#define EUD_INT_PET_EUD		BIT(0)
+#define EUD_INT_VBUS		BIT(2)
+#define EUD_INT_SAFE_MODE	BIT(4)
+#define EUD_INT_ALL		(EUD_INT_VBUS|EUD_INT_SAFE_MODE)
+
+struct eud_chip {
+	struct device			*dev;
+	struct usb_role_switch		*role_sw;
+	void __iomem			*eud_reg_base;
+	void __iomem			*eud_mode_mgr2_phys_base;
+	unsigned int			int_status;
+	int				eud_irq;
+	bool				enable;
+	bool				usb_attach;
+
+};
+
+static int enable_eud(struct eud_chip *priv)
+{
+	writel(EUD_ENABLE, priv->eud_reg_base + EUD_REG_CSR_EUD_EN);
+	writel(EUD_INT_VBUS | EUD_INT_SAFE_MODE,
+			priv->eud_reg_base + EUD_REG_INT1_EN_MASK);
+	writel(1, priv->eud_mode_mgr2_phys_base + EUD_REG_EUD_EN2);
+
+	return usb_role_switch_set_role(priv->role_sw, USB_ROLE_DEVICE);
+}
+
+static void disable_eud(struct eud_chip *priv)
+{
+	writel(0, priv->eud_reg_base + EUD_REG_CSR_EUD_EN);
+	writel(0, priv->eud_mode_mgr2_phys_base + EUD_REG_EUD_EN2);
+}
+
+static ssize_t enable_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct eud_chip *chip = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", chip->enable);
+}
+
+static ssize_t enable_store(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf, size_t count)
+{
+	struct eud_chip *chip = dev_get_drvdata(dev);
+	bool enable;
+	int ret;
+
+	if (kstrtobool(buf, &enable))
+		return -EINVAL;
+
+	if (enable) {
+		ret = enable_eud(chip);
+		if (!ret)
+			chip->enable = enable;
+	} else {
+		disable_eud(chip);
+	}
+
+	return count;
+}
+
+static DEVICE_ATTR_RW(enable);
+
+static struct attribute *eud_attrs[] = {
+	&dev_attr_enable.attr,
+	NULL,
+};
+
+static struct attribute_group attr_group = {
+	.attrs = eud_attrs,
+};
+
+static const struct attribute_group *attr_groups[] = {
+	&attr_group,
+	NULL
+};
+
+static void usb_attach_detach(struct eud_chip *chip)
+{
+	u32 reg;
+
+	/* read ctl_out_1[4] to find USB attach or detach event */
+	reg = readl(chip->eud_reg_base + EUD_REG_CTL_OUT_1);
+	if (reg & EUD_INT_SAFE_MODE)
+		chip->usb_attach = true;
+	else
+		chip->usb_attach = false;
+
+	/* set and clear vbus_int_clr[0] to clear interrupt */
+	writel(BIT(0), chip->eud_reg_base + EUD_REG_VBUS_INT_CLR);
+	writel(0, chip->eud_reg_base + EUD_REG_VBUS_INT_CLR);
+}
+
+static void pet_eud(struct eud_chip *chip)
+{
+	u32 reg;
+	int ret;
+
+	/* read sw_attach_det[0] to find attach/detach event */
+	reg = readl(chip->eud_reg_base +  EUD_REG_SW_ATTACH_DET);
+	if (reg & EUD_INT_PET_EUD) {
+		/* Detach & Attach pet for EUD */
+		writel(0, chip->eud_reg_base + EUD_REG_SW_ATTACH_DET);
+		/* Delay to make sure detach pet is done before attach pet */
+		ret = readl_poll_timeout(chip->eud_reg_base + EUD_REG_SW_ATTACH_DET,
+					reg, (reg == 0), 1, 100);
+		if (ret) {
+			dev_err(chip->dev, "Detach pet failed\n");
+			return;
+		}
+
+		writel(EUD_INT_PET_EUD, chip->eud_reg_base +
+				EUD_REG_SW_ATTACH_DET);
+	} else {
+		/* Attach pet for EUD */
+		writel(EUD_INT_PET_EUD, chip->eud_reg_base +
+				EUD_REG_SW_ATTACH_DET);
+	}
+}
+
+static irqreturn_t handle_eud_irq(int irq, void *data)
+{
+	struct eud_chip *chip = data;
+	u32 reg;
+
+	/* read status register and find out which interrupt triggered */
+	reg = readl(chip->eud_reg_base +  EUD_REG_INT_STATUS_1);
+	switch (reg & EUD_INT_ALL) {
+	case EUD_INT_VBUS:
+		chip->int_status = EUD_INT_VBUS;
+		usb_attach_detach(chip);
+		return IRQ_WAKE_THREAD;
+	case EUD_INT_SAFE_MODE:
+		pet_eud(chip);
+		break;
+	default:
+		return IRQ_NONE;
+	}
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t handle_eud_irq_thread(int irq, void *data)
+{
+	struct eud_chip *chip = data;
+	int ret;
+
+	if (chip->int_status == EUD_INT_VBUS) {
+		if (chip->usb_attach)
+			ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_DEVICE);
+		else
+			ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_HOST);
+		if (ret)
+			dev_err(chip->dev, "failed to set role switch\n");
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int eud_probe(struct platform_device *pdev)
+{
+	struct eud_chip *chip;
+	struct fwnode_handle *fwnode = pdev->dev.fwnode, *ep, *connector;
+	int ret;
+
+	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+	if (!chip)
+		return -ENOMEM;
+
+	chip->dev = &pdev->dev;
+
+	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
+	if (!ep)
+		return -ENODEV;
+
+	connector = fwnode_graph_get_remote_port_parent(ep);
+	fwnode_handle_put(ep);
+	if (!connector)
+		return -ENODEV;
+
+	chip->role_sw = fwnode_usb_role_switch_get(connector);
+	if (IS_ERR(chip->role_sw)) {
+		return dev_err_probe(chip->dev, PTR_ERR(chip->role_sw),
+					"failed to get role switch\n");
+	}
+
+	chip->eud_reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(chip->eud_reg_base))
+		return PTR_ERR(chip->eud_reg_base);
+
+	chip->eud_mode_mgr2_phys_base = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(chip->eud_mode_mgr2_phys_base))
+		return PTR_ERR(chip->eud_mode_mgr2_phys_base);
+
+	chip->eud_irq = platform_get_irq(pdev, 0);
+	ret = devm_request_threaded_irq(&pdev->dev, chip->eud_irq, handle_eud_irq,
+			handle_eud_irq_thread, IRQF_ONESHOT, NULL, chip);
+	if (ret)
+		return dev_err_probe(chip->dev, ret, "failed to allocate irq\n");
+
+	enable_irq_wake(chip->eud_irq);
+
+	platform_set_drvdata(pdev, chip);
+
+	return 0;
+}
+
+static int eud_remove(struct platform_device *pdev)
+{
+	struct eud_chip *chip = platform_get_drvdata(pdev);
+
+	if (chip->enable)
+		disable_eud(chip);
+
+	device_init_wakeup(&pdev->dev, false);
+	disable_irq_wake(chip->eud_irq);
+
+	return 0;
+}
+
+static const struct of_device_id eud_dt_match[] = {
+	{ .compatible = "qcom,sc7280-eud" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, eud_dt_match);
+
+static struct platform_driver eud_driver = {
+	.probe		= eud_probe,
+	.remove		= eud_remove,
+	.driver		= {
+		.name		= "eud",
+		.dev_groups	= attr_groups,
+		.of_match_table = eud_dt_match,
+	},
+};
+module_platform_driver(eud_driver);
+
+MODULE_DESCRIPTION("QTI EUD driver");
+MODULE_LICENSE("GPL v2");