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// 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/pm_runtime.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;
};
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;
}
pm_runtime_get_sync(dev);
/* 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)) {
pm_runtime_put(dev);
return 0;
}
/* Interval for polling is set to about 5 - 10 ms */
usleep_range(5000, 10000);
} while (time_before(jiffies, timeout));
pm_runtime_put(dev);
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;
pm_runtime_get_sync(dev);
val = readl(data->base + DUAL_ROLE_CFG0);
pm_runtime_put(dev);
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 const struct usb_role_switch_desc sw_desc = {
.set = intel_xhci_usb_set_role,
.get = intel_xhci_usb_get_role,
.allow_userspace_control = true,
};
static int intel_xhci_usb_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct intel_xhci_usb_data *data;
struct resource *res;
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -EINVAL;
data->base = devm_ioremap_nocache(dev, res->start, resource_size(res));
if (!data->base)
return -ENOMEM;
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);
pm_runtime_set_active(dev);
pm_runtime_enable(dev);
return 0;
}
static int intel_xhci_usb_remove(struct platform_device *pdev)
{
struct intel_xhci_usb_data *data = platform_get_drvdata(pdev);
pm_runtime_disable(&pdev->dev);
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");
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