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 #define DOCK_MODE_FLAG   0x80
  21
  22 MODULE_LICENSE("GPL");
  23 MODULE_AUTHOR("AceLan Kao");
  24
  25 static const struct acpi_device_id intel_vbtn_ids[] = {
  26         {"INT33D6", 0},
  27         {"", 0},
  28 };
  29
  30 /* In theory, these are HID usages. */
  31 static const struct key_entry intel_vbtn_keymap[] = {
  32         { KE_KEY, 0xC0, { KEY_POWER } },        /* power key press */
  33         { KE_IGNORE, 0xC1, { KEY_POWER } },     /* power key release */
  34         { KE_KEY, 0xC2, { KEY_LEFTMETA } },             /* 'Windows' key press */
  35         { KE_KEY, 0xC3, { KEY_LEFTMETA } },             /* 'Windows' key release */
  36         { KE_KEY, 0xC4, { KEY_VOLUMEUP } },             /* volume-up key press */
  37         { KE_IGNORE, 0xC5, { KEY_VOLUMEUP } },          /* volume-up key release */
  38         { KE_KEY, 0xC6, { KEY_VOLUMEDOWN } },           /* volume-down key press */
  39         { KE_IGNORE, 0xC7, { KEY_VOLUMEDOWN } },        /* volume-down key release */
  40         { KE_KEY,    0xC8, { KEY_ROTATE_LOCK_TOGGLE } },        /* rotate-lock key press */
  41         { KE_KEY,    0xC9, { KEY_ROTATE_LOCK_TOGGLE } },        /* rotate-lock key release */
  42         { KE_SW,     0xCA, { .sw = { SW_DOCK, 1 } } },          /* Docked */
  43         { KE_SW,     0xCB, { .sw = { SW_DOCK, 0 } } },          /* Undocked */
  44         { KE_SW,     0xCC, { .sw = { SW_TABLET_MODE, 1 } } },   /* Tablet */
  45         { KE_SW,     0xCD, { .sw = { SW_TABLET_MODE, 0 } } },   /* Laptop */
  46         { KE_END },
  47 };
  48
  49 struct intel_vbtn_priv {
  50         struct input_dev *input_dev;
  51         bool wakeup_mode;
  52 };
  53
  54 static int intel_vbtn_input_setup(struct platform_device *device)
  55 {
  56         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  57         int ret;
  58
  59         priv->input_dev = devm_input_allocate_device(&device->dev);
  60         if (!priv->input_dev)
  61                 return -ENOMEM;
  62
  63         ret = sparse_keymap_setup(priv->input_dev, intel_vbtn_keymap, NULL);
  64         if (ret)
  65                 return ret;
  66
  67         priv->input_dev->dev.parent = &device->dev;
  68         priv->input_dev->name = "Intel Virtual Button driver";
  69         priv->input_dev->id.bustype = BUS_HOST;
  70
  71         return input_register_device(priv->input_dev);
  72 }
  73
  74 static void notify_handler(acpi_handle handle, u32 event, void *context)
  75 {
  76         struct platform_device *device = context;
  77         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
  78         unsigned int val = !(event & 1); /* Even=press, Odd=release */
  79         const struct key_entry *ke, *ke_rel;
  80         bool autorelease;
  81
  82         if (priv->wakeup_mode) {
  83                 ke = sparse_keymap_entry_from_scancode(priv->input_dev, event);
  84                 if (ke) {
  85                         pm_wakeup_hard_event(&device->dev);
  86
  87                         /*
  88                          * Switch events like tablet mode will wake the device
  89                          * and report the new switch position to the input
  90                          * subsystem.
  91                          */
  92                         if (ke->type == KE_SW)
  93                                 sparse_keymap_report_event(priv->input_dev,
  94                                                            event,
  95                                                            val,
  96                                                            0);
  97                         return;
  98                 }
  99                 goto out_unknown;
 100         }
 101
 102         /*
 103          * Even press events are autorelease if there is no corresponding odd
 104          * release event, or if the odd event is KE_IGNORE.
 105          */
 106         ke_rel = sparse_keymap_entry_from_scancode(priv->input_dev, event | 1);
 107         autorelease = val && (!ke_rel || ke_rel->type == KE_IGNORE);
 108
 109         if (sparse_keymap_report_event(priv->input_dev, event, val, autorelease))
 110                 return;
 111
 112 out_unknown:
 113         dev_dbg(&device->dev, "unknown event index 0x%x\n", event);
 114 }
 115
 116 static void detect_tablet_mode(struct platform_device *device)
 117 {
 118         const char *chassis_type = dmi_get_system_info(DMI_CHASSIS_TYPE);
 119         struct intel_vbtn_priv *priv = dev_get_drvdata(&device->dev);
 120         acpi_handle handle = ACPI_HANDLE(&device->dev);
 121         struct acpi_buffer vgbs_output = { ACPI_ALLOCATE_BUFFER, NULL };
 122         union acpi_object *obj;
 123         acpi_status status;
 124         int m;
 125
 126         if (!(chassis_type && strcmp(chassis_type, "31") == 0))
 127                 goto out;
 128
 129         status = acpi_evaluate_object(handle, "VGBS", NULL, &vgbs_output);
 130         if (ACPI_FAILURE(status))
 131                 goto out;
 132
 133         obj = vgbs_output.pointer;
 134         if (!(obj && obj->type == ACPI_TYPE_INTEGER))
 135                 goto out;
 136
 137         m = !(obj->integer.value & TABLET_MODE_FLAG);
 138         input_report_switch(priv->input_dev, SW_TABLET_MODE, m);
 139         m = (obj->integer.value & DOCK_MODE_FLAG) ? 1 : 0;
 140         input_report_switch(priv->input_dev, SW_DOCK, m);
 141 out:
 142         kfree(vgbs_output.pointer);
 143 }
 144
 145 static int intel_vbtn_probe(struct platform_device *device)
 146 {
 147         acpi_handle handle = ACPI_HANDLE(&device->dev);
 148         struct intel_vbtn_priv *priv;
 149         acpi_status status;
 150         int err;
 151
 152         status = acpi_evaluate_object(handle, "VBDL", NULL, NULL);
 153         if (ACPI_FAILURE(status)) {
 154                 dev_warn(&device->dev, "failed to read Intel Virtual Button driver\n");
 155                 return -ENODEV;
 156         }
 157
 158         priv = devm_kzalloc(&device->dev, sizeof(*priv), GFP_KERNEL);
 159         if (!priv)
 160                 return -ENOMEM;
 161         dev_set_drvdata(&device->dev, priv);
 162
 163         err = intel_vbtn_input_setup(device);
 164         if (err) {
 165                 pr_err("Failed to setup Intel Virtual Button\n");
 166                 return err;
 167         }
 168
 169         detect_tablet_mode(device);
 170
 171         status = acpi_install_notify_handler(handle,
 172                                              ACPI_DEVICE_NOTIFY,
 173                                              notify_handler,
 174                                              device);
 175         if (ACPI_FAILURE(status))
 176                 return -EBUSY;
 177
 178         device_init_wakeup(&device->dev, true);
 179         return 0;
 180 }
 181
 182 static int intel_vbtn_remove(struct platform_device *device)
 183 {
 184         acpi_handle handle = ACPI_HANDLE(&device->dev);
 185
 186         device_init_wakeup(&device->dev, false);
 187         acpi_remove_notify_handler(handle, ACPI_DEVICE_NOTIFY, notify_handler);
 188
 189         /*
 190          * Even if we failed to shut off the event stream, we can still
 191          * safely detach from the device.
 192          */
 193         return 0;
 194 }
 195
 196 static int intel_vbtn_pm_prepare(struct device *dev)
 197 {
 198         struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
 199
 200         priv->wakeup_mode = true;
 201         return 0;
 202 }
 203
 204 static int intel_vbtn_pm_resume(struct device *dev)
 205 {
 206         struct intel_vbtn_priv *priv = dev_get_drvdata(dev);
 207
 208         priv->wakeup_mode = false;
 209         return 0;
 210 }
 211
 212 static const struct dev_pm_ops intel_vbtn_pm_ops = {
 213         .prepare = intel_vbtn_pm_prepare,
 214         .resume = intel_vbtn_pm_resume,
 215         .restore = intel_vbtn_pm_resume,
 216         .thaw = intel_vbtn_pm_resume,
 217 };
 218
 219 static struct platform_driver intel_vbtn_pl_driver = {
 220         .driver = {
 221                 .name = "intel-vbtn",
 222                 .acpi_match_table = intel_vbtn_ids,
 223                 .pm = &intel_vbtn_pm_ops,
 224         },
 225         .probe = intel_vbtn_probe,
 226         .remove = intel_vbtn_remove,
 227 };
 228 MODULE_DEVICE_TABLE(acpi, intel_vbtn_ids);
 229
 230 static acpi_status __init
 231 check_acpi_dev(acpi_handle handle, u32 lvl, void *context, void **rv)
 232 {
 233         const struct acpi_device_id *ids = context;
 234         struct acpi_device *dev;
 235
 236         if (acpi_bus_get_device(handle, &dev) != 0)
 237                 return AE_OK;
 238
 239         if (acpi_match_device_ids(dev, ids) == 0)
 240                 if (acpi_create_platform_device(dev, NULL))
 241                         dev_info(&dev->dev,
 242                                  "intel-vbtn: created platform device\n");
 243
 244         return AE_OK;
 245 }
 246
 247 static int __init intel_vbtn_init(void)
 248 {
 249         acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 250                             ACPI_UINT32_MAX, check_acpi_dev, NULL,
 251                             (void *)intel_vbtn_ids, NULL);
 252
 253         return platform_driver_register(&intel_vbtn_pl_driver);
 254 }
 255 module_init(intel_vbtn_init);
 256
 257 static void __exit intel_vbtn_exit(void)
 258 {
 259         platform_driver_unregister(&intel_vbtn_pl_driver);
 260 }
 261 module_exit(intel_vbtn_exit);