1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Intel XHCI (Cherry Trail, Broxton and others) USB OTG role switch driver
  4 *
  5 * Copyright (c) 2016-2017 Hans de Goede <hdegoede@redhat.com>
  6 *
  7 * Loosely based on android x86 kernel code which is:
  8 *
  9 * Copyright (C) 2014 Intel Corp.
 10 *
 11 * Author: Wu, Hao
 12 */
 13
 14#include <linux/acpi.h>
 15#include <linux/delay.h>
 16#include <linux/err.h>
 17#include <linux/io.h>
 18#include <linux/kernel.h>
 19#include <linux/module.h>
 20#include <linux/platform_device.h>
 21#include <linux/usb/role.h>
 22
 23/* register definition */
 24#define DUAL_ROLE_CFG0			0x68
 25#define SW_VBUS_VALID			BIT(24)
 26#define SW_IDPIN_EN			BIT(21)
 27#define SW_IDPIN			BIT(20)
 28
 29#define DUAL_ROLE_CFG1			0x6c
 30#define HOST_MODE			BIT(29)
 31
 32#define DUAL_ROLE_CFG1_POLL_TIMEOUT	1000
 33
 34#define DRV_NAME			"intel_xhci_usb_sw"
 35
 36struct intel_xhci_usb_data {
 37	struct usb_role_switch *role_sw;
 38	void __iomem *base;
 39};
 40
 41struct intel_xhci_acpi_match {
 42	const char *hid;
 43	int hrv;
 44};
 45
 46/*
 47 * ACPI IDs for PMICs which do not support separate data and power role
 48 * detection (USB ACA detection for micro USB OTG), we allow userspace to
 49 * change the role manually on these.
 50 */
 51static const struct intel_xhci_acpi_match allow_userspace_ctrl_ids[] = {
 52	{ "INT33F4",  3 }, /* X-Powers AXP288 PMIC */
 53};
 54
 55static int intel_xhci_usb_set_role(struct device *dev, enum usb_role role)
 56{
 57	struct intel_xhci_usb_data *data = dev_get_drvdata(dev);
 58	unsigned long timeout;
 59	acpi_status status;
 60	u32 glk, val;
 61
 62	/*
 63	 * On many CHT devices ACPI event (_AEI) handlers read / modify /
 64	 * write the cfg0 register, just like we do. Take the ACPI lock
 65	 * to avoid us racing with the AML code.
 66	 */
 67	status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
 68	if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
 69		dev_err(dev, "Error could not acquire lock\n");
 70		return -EIO;
 71	}
 72
 73	/* Set idpin value as requested */
 74	val = readl(data->base + DUAL_ROLE_CFG0);
 75	switch (role) {
 76	case USB_ROLE_NONE:
 77		val |= SW_IDPIN;
 78		val &= ~SW_VBUS_VALID;
 79		break;
 80	case USB_ROLE_HOST:
 81		val &= ~SW_IDPIN;
 82		val &= ~SW_VBUS_VALID;
 83		break;
 84	case USB_ROLE_DEVICE:
 85		val |= SW_IDPIN;
 86		val |= SW_VBUS_VALID;
 87		break;
 88	}
 89	val |= SW_IDPIN_EN;
 90
 91	writel(val, data->base + DUAL_ROLE_CFG0);
 92
 93	acpi_release_global_lock(glk);
 94
 95	/* In most case it takes about 600ms to finish mode switching */
 96	timeout = jiffies + msecs_to_jiffies(DUAL_ROLE_CFG1_POLL_TIMEOUT);
 97
 98	/* Polling on CFG1 register to confirm mode switch.*/
 99	do {
100		val = readl(data->base + DUAL_ROLE_CFG1);
101		if (!!(val & HOST_MODE) == (role == USB_ROLE_HOST))
102			return 0;
103
104		/* Interval for polling is set to about 5 - 10 ms */
105		usleep_range(5000, 10000);
106	} while (time_before(jiffies, timeout));
107
108	dev_warn(dev, "Timeout waiting for role-switch\n");
109	return -ETIMEDOUT;
110}
111
112static enum usb_role intel_xhci_usb_get_role(struct device *dev)
113{
114	struct intel_xhci_usb_data *data = dev_get_drvdata(dev);
115	enum usb_role role;
116	u32 val;
117
118	val = readl(data->base + DUAL_ROLE_CFG0);
119
120	if (!(val & SW_IDPIN))
121		role = USB_ROLE_HOST;
122	else if (val & SW_VBUS_VALID)
123		role = USB_ROLE_DEVICE;
124	else
125		role = USB_ROLE_NONE;
126
127	return role;
128}
129
130static struct usb_role_switch_desc sw_desc = {
131	.set = intel_xhci_usb_set_role,
132	.get = intel_xhci_usb_get_role,
133};
134
135static int intel_xhci_usb_probe(struct platform_device *pdev)
136{
137	struct device *dev = &pdev->dev;
138	struct intel_xhci_usb_data *data;
139	struct resource *res;
140	int i;
141
142	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
143	if (!data)
144		return -ENOMEM;
145
146	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
147	data->base = devm_ioremap_nocache(dev, res->start, resource_size(res));
148	if (!data->base)
149		return -ENOMEM;
150
151	for (i = 0; i < ARRAY_SIZE(allow_userspace_ctrl_ids); i++)
152		if (acpi_dev_present(allow_userspace_ctrl_ids[i].hid, "1",
153				     allow_userspace_ctrl_ids[i].hrv))
154			sw_desc.allow_userspace_control = true;
155
156	platform_set_drvdata(pdev, data);
157
158	data->role_sw = usb_role_switch_register(dev, &sw_desc);
159	if (IS_ERR(data->role_sw))
160		return PTR_ERR(data->role_sw);
161
162	return 0;
163}
164
165static int intel_xhci_usb_remove(struct platform_device *pdev)
166{
167	struct intel_xhci_usb_data *data = platform_get_drvdata(pdev);
168
169	usb_role_switch_unregister(data->role_sw);
170	return 0;
171}
172
173static const struct platform_device_id intel_xhci_usb_table[] = {
174	{ .name = DRV_NAME },
175	{}
176};
177MODULE_DEVICE_TABLE(platform, intel_xhci_usb_table);
178
179static struct platform_driver intel_xhci_usb_driver = {
180	.driver = {
181		.name = DRV_NAME,
182	},
183	.id_table = intel_xhci_usb_table,
184	.probe = intel_xhci_usb_probe,
185	.remove = intel_xhci_usb_remove,
186};
187
188module_platform_driver(intel_xhci_usb_driver);
189
190MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
191MODULE_DESCRIPTION("Intel XHCI USB role switch driver");
192MODULE_LICENSE("GPL");