drivers/platform/x86/intel-vbtn.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  Intel Virtual Button driver for Windows 8.1+
   4  *
   5  *  Copyright (C) 2016 AceLan Kao <acelan.kao@canonical.com>
   6  *  Copyright (C) 2016 Alex Hung <alex.hung@canonical.com>
   7  */
   8
   9 #include <linux/acpi.h>
  10 #include <linux/dmi.h>
  11 #include <linux/input.h>
  12 #include <linux/input/sparse-keymap.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/suspend.h>
  17
  18 /* When NOT in tablet mode, VGBS returns with the flag 0x40 */
  19 #define TABLET_MODE_FLAG 0x40
  20
  21 MODULE_LICENSE("GPL");
  22 MODULE_AUTHOR("AceLan Kao");
  23
  24 static const struct acpi_device_id intel_vbtn_ids[] = {
  25         {"INT33D6", 0},
  26         {"", 0},
  27 };
  28
  29 /* In theory, these are HID usages. */
  30 static const struct key_entry intel_vbtn_keymap[] = {
  31         { KE_KEY, 0xC0, { KEY_POWER } },        /* power key press */
  32         { KE_IGNORE, 0xC1, { KEY_POWER } },     /* power key release */
  33         { KE_KEY, 0xC2, { KEY_LEFTMETA } },             /* 'Windows' key press */
  34         { KE_KEY, 0xC3, { KEY_LEFTMETA } },             /* 'Windows' key release */
  35         { KE_KEY, 0xC4, { KEY_VOLUMEUP } },             /* volume-up key press */
  36         { KE_IGNORE, 0xC5, { KEY_VOLUMEUP } },          /* volume-up key release */
  37         { KE_KEY, 0xC6, { KEY_VOLUMEDOWN } },           /* volume-down key press */
  38         { KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN } },        /* volume-down key release */
  39         { KE_KEY,    0xC8, { KEY_ROTATE_LOCK_TOGGLE } },        /* rotate-lock key press */
  40         { KE_KEY,    0xC9, { KEY_ROTATE_LOCK_TOGGLE } },        /* rotate-lock key release */
  41         { KE_SW,     0xCC, { .sw = { SW_TABLET_MODE, 1 } } },   /* Tablet */
  42         { KE_SW,     0xCD, { .sw = { SW_TABLET_MODE, 0 } } },   /* Laptop */
  43         { KE_END },
  44 };
  45
  46 struct intel_vbtn_priv {
  47         struct input_dev *input_dev;
  48         bool wakeup_mode;
  49 };
  50
  51 static int intel_vbtn_input_setup(struct platform_device *device)
  52 {
  53         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  54         int ret;
  55
  56         priv->input_dev = devm_input_allocate_device(&device->dev);
  57         if (!priv->input_dev)
  58                 return -ENOMEM;
  59
  60         ret = sparse_keymap_setup(priv->input_dev, intel_vbtn_keymap, NULL);
  61         if (ret)
  62                 return ret;
  63
  64         priv->input_dev->dev.parent = &device->dev;
  65         priv->input_dev->name = "Intel Virtual Button driver";
  66         priv->input_dev->id.bustype = BUS_HOST;
  67
  68         return input_register_device(priv->input_dev);
  69 }
  70
  71 static void notify_handler(acpi_handle handle, u32 event, void *context)
  72 {
  73         struct platform_device *device = context;
  74         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  75         unsigned int val = !(event & 1); /* Even=press, Odd=release */
  76         const struct key_entry *ke_rel;
  77         bool autorelease;
  78
  79         if (priv->wakeup_mode) {
  80                 if (sparse_keymap_entry_from_scancode(priv->input_dev, event)) {
  81                         pm_wakeup_hard_event(&device->dev);
  82                         return;
  83                 }
  84                 goto out_unknown;
  85         }
  86
  87         /*
  88          * Even press events are autorelease if there is no corresponding odd
  89          * release event, or if the odd event is KE_IGNORE.
  90          */
  91         ke_rel = sparse_keymap_entry_from_scancode(priv->input_dev, event | 1);
  92         autorelease = val && (!ke_rel || ke_rel->type == KE_IGNORE);
  93
  94         if (sparse_keymap_report_event(priv->input_dev, event, val, autorelease))
  95                 return;
  96
  97 out_unknown:
  98         dev_dbg(&device->dev, "unknown event index 0x%x\n", event);
  99 }
 100
 101 static void detect_tablet_mode(struct platform_device *device)
 102 {
 103         const char *chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
 104         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
 105         acpi_handle handle = ACPI_HANDLE(&device->dev);
 106         struct acpi_buffer vgbs_output = { ACPI_ALLOCATE_BUFFER, NULL };
 107         union acpi_object *obj;
 108         acpi_status status;
 109         int m;
 110
 111         if (!(chassis_type && strcmp(chassis_type, "31") == 0))
 112                 goto out;
 113
 114         status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
 115         if (ACPI_FAILURE(status))
 116                 goto out;
 117
 118         obj = vgbs_output.pointer;
 119         if (!(obj && obj->type == ACPI_TYPE_INTEGER))
 120                 goto out;
 121
 122         m = !(obj->integer.value & TABLET_MODE_FLAG);
 123         input_report_switch(priv->input_dev, SW_TABLET_MODE, m);
 124 out:
 125         kfree(vgbs_output.pointer);
 126 }
 127
 128 static int intel_vbtn_probe(struct platform_device *device)
 129 {
 130         acpi_handle handle = ACPI_HANDLE(&device->dev);
 131         struct intel_vbtn_priv *priv;
 132         acpi_status status;
 133         int err;
 134
 135         status = acpi_evaluate_object(handle, "VBDL", NULL, NULL);
 136         if (ACPI_FAILURE(status)) {
 137                 dev_warn(&device->dev, "failed to read Intel Virtual Button driver\n");
 138                 return -ENODEV;
 139         }
 140
 141         priv = devm_kzalloc(&device->dev, sizeof(*priv), GFP_KERNEL);
 142         if (!priv)
 143                 return -ENOMEM;
 144         dev_set_drvdata(&device->dev, priv);
 145
 146         err = intel_vbtn_input_setup(device);
 147         if (err) {
 148                 pr_err("Failed to setup Intel Virtual Button\n");
 149                 return err;
 150         }
 151
 152         detect_tablet_mode(device);
 153
 154         status = acpi_install_notify_handler(handle,
 155                                              ACPI_DEVICE_NOTIFY,
 156                                              notify_handler,
 157                                              device);
 158         if (ACPI_FAILURE(status))
 159                 return -EBUSY;
 160
 161         device_init_wakeup(&device->dev, true);
 162         return 0;
 163 }
 164
 165 static int intel_vbtn_remove(struct platform_device *device)
 166 {
 167         acpi_handle handle = ACPI_HANDLE(&device->dev);
 168
 169         device_init_wakeup(&device->dev, false);
 170         acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
 171
 172         /*
 173          * Even if we failed to shut off the event stream, we can still
 174          * safely detach from the device.
 175          */
 176         return 0;
 177 }
 178
 179 static int intel_vbtn_pm_prepare(struct device *dev)
 180 {
 181         struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
 182
 183         priv->wakeup_mode = true;
 184         return 0;
 185 }
 186
 187 static int intel_vbtn_pm_resume(struct device *dev)
 188 {
 189         struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
 190
 191         priv->wakeup_mode = false;
 192         return 0;
 193 }
 194
 195 static const struct dev_pm_ops intel_vbtn_pm_ops = {
 196         .prepare = intel_vbtn_pm_prepare,
 197         .resume = intel_vbtn_pm_resume,
 198         .restore = intel_vbtn_pm_resume,
 199         .thaw = intel_vbtn_pm_resume,
 200 };
 201
 202 static struct platform_driver intel_vbtn_pl_driver = {
 203         .driver = {
 204                 .name = "intel-vbtn",
 205                 .acpi_match_table = intel_vbtn_ids,
 206                 .pm = &intel_vbtn_pm_ops,
 207         },
 208         .probe = intel_vbtn_probe,
 209         .remove = intel_vbtn_remove,
 210 };
 211 MODULE_DEVICE_TABLE(acpi, intel_vbtn_ids);
 212
 213 static acpi_status __init
 214 check_acpi_dev(acpi_handle handle, u32 lvl, void *context, void **rv)
 215 {
 216         const struct acpi_device_id *ids = context;
 217         struct acpi_device *dev;
 218
 219         if (acpi_bus_get_device(handle, &dev) != 0)
 220                 return AE_OK;
 221
 222         if (acpi_match_device_ids(dev, ids) == 0)
 223                 if (acpi_create_platform_device(dev, NULL))
 224                         dev_info(&dev->dev,
 225                                  "intel-vbtn: created platform device\n");
 226
 227         return AE_OK;
 228 }
 229
 230 static int __init intel_vbtn_init(void)
 231 {
 232         acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 233                             ACPI_UINT32_MAX, check_acpi_dev, NULL,
 234                             (void *)intel_vbtn_ids, NULL);
 235
 236         return platform_driver_register(&intel_vbtn_pl_driver);
 237 }
 238 module_init(intel_vbtn_init);
 239
 240 static void __exit intel_vbtn_exit(void)
 241 {
 242         platform_driver_unregister(&intel_vbtn_pl_driver);
 243 }
 244 module_exit(intel_vbtn_exit);