drivers/usb/roles/intel-xhci-usb-role-switch.c

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