5 files changed, 211 insertions, 0 deletions

diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index f278958e04ca..75f7fb151f71 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -171,6 +171,8 @@ source "drivers/usb/gadget/Kconfig"
 
 source "drivers/usb/typec/Kconfig"
 
+source "drivers/usb/roles/Kconfig"
+
 config USB_LED_TRIG
         bool "USB LED Triggers"
         depends on LEDS_CLASS && LEDS_TRIGGERS
diff --git a/drivers/usb/Makefile b/drivers/usb/Makefile
index 060643a1b5c8..7d1b8c82b208 100644
--- a/drivers/usb/Makefile
+++ b/drivers/usb/Makefile
@@ -65,3 +65,5 @@ obj-$(CONFIG_USB_COMMON)	+= common/
 obj-$(CONFIG_USBIP_CORE)        += usbip/
 
 obj-$(CONFIG_TYPEC)             += typec/
+
+obj-$(CONFIG_USB_ROLE_SWITCH)   += roles/
diff --git a/drivers/usb/roles/Kconfig b/drivers/usb/roles/Kconfig
new file mode 100644
index 000000000000..f5a5e6f79f1b
--- /dev/null
+++ b/drivers/usb/roles/Kconfig
@@ -0,0 +1,14 @@
+if USB_ROLE_SWITCH
+
+config USB_ROLES_INTEL_XHCI
+        tristate "Intel XHCI USB Role Switch"
+        depends on ACPI && X86
+        help
+          Driver for the internal USB role switch for switching the USB data
+          lines between the xHCI host controller and the dwc3 gadget controller
+          found on various Intel SoCs.
+
+          To compile the driver as a module, choose M here: the module will
+          be called intel-xhci-usb-role-switch.
+
+endif # USB_ROLE_SWITCH
diff --git a/drivers/usb/roles/Makefile b/drivers/usb/roles/Makefile
new file mode 100644
index 000000000000..e44b179ba275
--- /dev/null
+++ b/drivers/usb/roles/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_USB_ROLES_INTEL_XHCI) += intel-xhci-usb-role-switch.o
diff --git a/drivers/usb/roles/intel-xhci-usb-role-switch.c b/drivers/usb/roles/intel-xhci-usb-role-switch.c
new file mode 100644
index 000000000000..58c1b60a33c1
--- /dev/null
+++ b/drivers/usb/roles/intel-xhci-usb-role-switch.c
@@ -0,0 +1,192 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Intel XHCI (Cherry Trail, Broxton and others) USB OTG role switch driver
+ *
+ * Copyright (c) 2016-2017 Hans de Goede <hdegoede@redhat.com>
+ *
+ * Loosely based on android x86 kernel code which is:
+ *
+ * Copyright (C) 2014 Intel Corp.
+ *
+ * Author: Wu, Hao
+ */
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/usb/role.h>
+
+/* register definition */
+#define DUAL_ROLE_CFG0                  0x68
+#define SW_VBUS_VALID                   BIT(24)
+#define SW_IDPIN_EN                     BIT(21)
+#define SW_IDPIN                        BIT(20)
+
+#define DUAL_ROLE_CFG1                  0x6c
+#define HOST_MODE                       BIT(29)
+
+#define DUAL_ROLE_CFG1_POLL_TIMEOUT     1000
+
+#define DRV_NAME                        "intel_xhci_usb_sw"
+
+struct intel_xhci_usb_data {
+        struct usb_role_switch *role_sw;
+        void __iomem *base;
+};
+
+struct intel_xhci_acpi_match {
+        const char *hid;
+        int hrv;
+};
+
+/*
+ * ACPI IDs for PMICs which do not support separate data and power role
+ * detection (USB ACA detection for micro USB OTG), we allow userspace to
+ * change the role manually on these.
+ */
+static const struct intel_xhci_acpi_match allow_userspace_ctrl_ids[] = {
+        { "INT33F4",  3 }, /* X-Powers AXP288 PMIC */
+};
+
+static int intel_xhci_usb_set_role(struct device *dev, enum usb_role role)
+{
+        struct intel_xhci_usb_data *data = dev_get_drvdata(dev);
+        unsigned long timeout;
+        acpi_status status;
+        u32 glk, val;
+
+        /*
+         * On many CHT devices ACPI event (_AEI) handlers read / modify /
+         * write the cfg0 register, just like we do. Take the ACPI lock
+         * to avoid us racing with the AML code.
+         */
+        status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
+        if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
+                dev_err(dev, "Error could not acquire lock\n");
+                return -EIO;
+        }
+
+        /* Set idpin value as requested */
+        val = readl(data->base + DUAL_ROLE_CFG0);
+        switch (role) {
+        case USB_ROLE_NONE:
+                val |= SW_IDPIN;
+                val &= ~SW_VBUS_VALID;
+                break;
+        case USB_ROLE_HOST:
+                val &= ~SW_IDPIN;
+                val &= ~SW_VBUS_VALID;
+                break;
+        case USB_ROLE_DEVICE:
+                val |= SW_IDPIN;
+                val |= SW_VBUS_VALID;
+                break;
+        }
+        val |= SW_IDPIN_EN;
+
+        writel(val, data->base + DUAL_ROLE_CFG0);
+
+        acpi_release_global_lock(glk);
+
+        /* In most case it takes about 600ms to finish mode switching */
+        timeout = jiffies + msecs_to_jiffies(DUAL_ROLE_CFG1_POLL_TIMEOUT);
+
+        /* Polling on CFG1 register to confirm mode switch.*/
+        do {
+                val = readl(data->base + DUAL_ROLE_CFG1);
+                if (!!(val & HOST_MODE) == (role == USB_ROLE_HOST))
+                        return 0;
+
+                /* Interval for polling is set to about 5 - 10 ms */
+                usleep_range(5000, 10000);
+        } while (time_before(jiffies, timeout));
+
+        dev_warn(dev, "Timeout waiting for role-switch\n");
+        return -ETIMEDOUT;
+}
+
+static enum usb_role intel_xhci_usb_get_role(struct device *dev)
+{
+        struct intel_xhci_usb_data *data = dev_get_drvdata(dev);
+        enum usb_role role;
+        u32 val;
+
+        val = readl(data->base + DUAL_ROLE_CFG0);
+
+        if (!(val & SW_IDPIN))
+                role = USB_ROLE_HOST;
+        else if (val & SW_VBUS_VALID)
+                role = USB_ROLE_DEVICE;
+        else
+                role = USB_ROLE_NONE;
+
+        return role;
+}
+
+static struct usb_role_switch_desc sw_desc = {
+        .set = intel_xhci_usb_set_role,
+        .get = intel_xhci_usb_get_role,
+};
+
+static int intel_xhci_usb_probe(struct platform_device *pdev)
+{
+        struct device *dev = &pdev->dev;
+        struct intel_xhci_usb_data *data;
+        struct resource *res;
+        int i;
+
+        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+
+        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        data->base = devm_ioremap_nocache(dev, res->start, resource_size(res));
+        if (IS_ERR(data->base))
+                return PTR_ERR(data->base);
+
+        for (i = 0; i < ARRAY_SIZE(allow_userspace_ctrl_ids); i++)
+                if (acpi_dev_present(allow_userspace_ctrl_ids[i].hid, "1",
+                                     allow_userspace_ctrl_ids[i].hrv))
+                        sw_desc.allow_userspace_control = true;
+
+        platform_set_drvdata(pdev, data);
+
+        data->role_sw = usb_role_switch_register(dev, &sw_desc);
+        if (IS_ERR(data->role_sw))
+                return PTR_ERR(data->role_sw);
+
+        return 0;
+}
+
+static int intel_xhci_usb_remove(struct platform_device *pdev)
+{
+        struct intel_xhci_usb_data *data = platform_get_drvdata(pdev);
+
+        usb_role_switch_unregister(data->role_sw);
+        return 0;
+}
+
+static const struct platform_device_id intel_xhci_usb_table[] = {
+        { .name = DRV_NAME },
+        {}
+};
+MODULE_DEVICE_TABLE(platform, intel_xhci_usb_table);
+
+static struct platform_driver intel_xhci_usb_driver = {
+        .driver = {
+                .name = DRV_NAME,
+        },
+        .id_table = intel_xhci_usb_table,
+        .probe = intel_xhci_usb_probe,
+        .remove = intel_xhci_usb_remove,
+};
+
+module_platform_driver(intel_xhci_usb_driver);
+
+MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
+MODULE_DESCRIPTION("Intel XHCI USB role switch driver");
+MODULE_LICENSE("GPL");