drivers/platform/x86/surface3-wmi.c

   1 /*
   2  *  Driver for the LID cover switch of the Surface 3
   3  *
   4  *  Copyright (c) 2016 Red Hat Inc.
   5  */
   6
   7 /*
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the Free
  10  * Software Foundation; version 2 of the License.
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/slab.h>
  16
  17 #include <linux/acpi.h>
  18 #include <linux/dmi.h>
  19 #include <linux/input.h>
  20 #include <linux/mutex.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/spi/spi.h>
  23
  24 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@redhat.com>");
  25 MODULE_DESCRIPTION("Surface 3 platform driver");
  26 MODULE_LICENSE("GPL");
  27
  28 #define ACPI_BUTTON_HID_LID             "PNP0C0D"
  29 #define SPI_CTL_OBJ_NAME                "SPI"
  30 #define SPI_TS_OBJ_NAME                 "NTRG"
  31
  32 #define SURFACE3_LID_GUID "F7CC25EC-D20B-404C-8903-0ED4359C18AE"
  33
  34 MODULE_ALIAS("wmi:" SURFACE3_LID_GUID);
  35
  36 static const struct dmi_system_id surface3_dmi_table[] = {
  37 #if defined(CONFIG_X86)
  38         {
  39                 .matches = {
  40                         DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
  41                         DMI_MATCH(DMI_PRODUCT_NAME, "Surface 3"),
  42                 },
  43         },
  44 #endif
  45         { }
  46 };
  47
  48 struct surface3_wmi {
  49         struct acpi_device *touchscreen_adev;
  50         struct acpi_device *pnp0c0d_adev;
  51         struct acpi_hotplug_context hp;
  52         struct input_dev *input;
  53 };
  54
  55 static struct platform_device *s3_wmi_pdev;
  56
  57 static struct surface3_wmi s3_wmi;
  58
  59 static DEFINE_MUTEX(s3_wmi_lock);
  60
  61 static int s3_wmi_query_block(const char *guid, int instance, int *ret)
  62 {
  63         struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
  64         acpi_status status;
  65         union acpi_object *obj;
  66         int error = 0;
  67
  68         mutex_lock(&s3_wmi_lock);
  69         status = wmi_query_block(guid, instance, &output);
  70
  71         obj = output.pointer;
  72
  73         if (!obj || obj->type != ACPI_TYPE_INTEGER) {
  74                 if (obj) {
  75                         pr_err("query block returned object type: %d - buffer length:%d\n",
  76                                obj->type,
  77                                obj->type == ACPI_TYPE_BUFFER ?
  78                                                 obj->buffer.length : 0);
  79                 }
  80                 error = -EINVAL;
  81                 goto out_free_unlock;
  82         }
  83         *ret = obj->integer.value;
  84  out_free_unlock:
  85         kfree(obj);
  86         mutex_unlock(&s3_wmi_lock);
  87         return error;
  88 }
  89
  90 static inline int s3_wmi_query_lid(int *ret)
  91 {
  92         return s3_wmi_query_block(SURFACE3_LID_GUID, 0, ret);
  93 }
  94
  95 static int s3_wmi_send_lid_state(void)
  96 {
  97         int ret, lid_sw;
  98
  99         ret = s3_wmi_query_lid(&lid_sw);
 100         if (ret)
 101                 return ret;
 102
 103         input_report_switch(s3_wmi.input, SW_LID, lid_sw);
 104         input_sync(s3_wmi.input);
 105
 106         return 0;
 107 }
 108
 109 static int s3_wmi_hp_notify(struct acpi_device *adev, u32 value)
 110 {
 111         return s3_wmi_send_lid_state();
 112 }
 113
 114 static acpi_status s3_wmi_attach_spi_device(acpi_handle handle,
 115                                             u32 level,
 116                                             void *data,
 117                                             void **return_value)
 118 {
 119         struct acpi_device *adev, **ts_adev;
 120
 121         if (acpi_bus_get_device(handle, &adev))
 122                 return AE_OK;
 123
 124         ts_adev = data;
 125
 126         if (strncmp(acpi_device_bid(adev), SPI_TS_OBJ_NAME,
 127             strlen(SPI_TS_OBJ_NAME)))
 128                 return AE_OK;
 129
 130         if (*ts_adev) {
 131                 pr_err("duplicate entry %s\n", SPI_TS_OBJ_NAME);
 132                 return AE_OK;
 133         }
 134
 135         *ts_adev = adev;
 136
 137         return AE_OK;
 138 }
 139
 140 static int s3_wmi_check_platform_device(struct device *dev, void *data)
 141 {
 142         struct acpi_device *adev, *ts_adev = NULL;
 143         acpi_handle handle;
 144         acpi_status status;
 145
 146         /* ignore non ACPI devices */
 147         handle = ACPI_HANDLE(dev);
 148         if (!handle || acpi_bus_get_device(handle, &adev))
 149                 return 0;
 150
 151         /* check for LID ACPI switch */
 152         if (!strcmp(ACPI_BUTTON_HID_LID, acpi_device_hid(adev))) {
 153                 s3_wmi.pnp0c0d_adev = adev;
 154                 return 0;
 155         }
 156
 157         /* ignore non SPI controllers */
 158         if (strncmp(acpi_device_bid(adev), SPI_CTL_OBJ_NAME,
 159             strlen(SPI_CTL_OBJ_NAME)))
 160                 return 0;
 161
 162         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
 163                                      s3_wmi_attach_spi_device, NULL,
 164                                      &ts_adev, NULL);
 165         if (ACPI_FAILURE(status))
 166                 dev_warn(dev, "failed to enumerate SPI slaves\n");
 167
 168         if (!ts_adev)
 169                 return 0;
 170
 171         s3_wmi.touchscreen_adev = ts_adev;
 172
 173         return 0;
 174 }
 175
 176 static int s3_wmi_create_and_register_input(struct platform_device *pdev)
 177 {
 178         struct input_dev *input;
 179         int error;
 180
 181         input = devm_input_allocate_device(&pdev->dev);
 182         if (!input)
 183                 return -ENOMEM;
 184
 185         input->name = "Lid Switch";
 186         input->phys = "button/input0";
 187         input->id.bustype = BUS_HOST;
 188         input->id.product = 0x0005;
 189
 190         input_set_capability(input, EV_SW, SW_LID);
 191
 192         error = input_register_device(input);
 193         if (error)
 194                 goto out_err;
 195
 196         s3_wmi.input = input;
 197
 198         return 0;
 199  out_err:
 200         input_free_device(s3_wmi.input);
 201         return error;
 202 }
 203
 204 static int __init s3_wmi_probe(struct platform_device *pdev)
 205 {
 206         int error;
 207
 208         if (!dmi_check_system(surface3_dmi_table))
 209                 return -ENODEV;
 210
 211         memset(&s3_wmi, 0, sizeof(s3_wmi));
 212
 213         bus_for_each_dev(&platform_bus_type, NULL, NULL,
 214                          s3_wmi_check_platform_device);
 215
 216         if (!s3_wmi.touchscreen_adev)
 217                 return -ENODEV;
 218
 219         acpi_bus_trim(s3_wmi.pnp0c0d_adev);
 220
 221         error = s3_wmi_create_and_register_input(pdev);
 222         if (error)
 223                 goto restore_acpi_lid;
 224
 225         acpi_initialize_hp_context(s3_wmi.touchscreen_adev, &s3_wmi.hp,
 226                                    s3_wmi_hp_notify, NULL);
 227
 228         s3_wmi_send_lid_state();
 229
 230         return 0;
 231
 232  restore_acpi_lid:
 233         acpi_bus_scan(s3_wmi.pnp0c0d_adev->handle);
 234         return error;
 235 }
 236
 237 static int s3_wmi_remove(struct platform_device *device)
 238 {
 239         /* remove the hotplug context from the acpi device */
 240         s3_wmi.touchscreen_adev->hp = NULL;
 241
 242         /* reinstall the actual PNPC0C0D LID default handle */
 243         acpi_bus_scan(s3_wmi.pnp0c0d_adev->handle);
 244         return 0;
 245 }
 246
 247 static int __maybe_unused s3_wmi_resume(struct device *dev)
 248 {
 249         s3_wmi_send_lid_state();
 250         return 0;
 251 }
 252 static SIMPLE_DEV_PM_OPS(s3_wmi_pm, NULL, s3_wmi_resume);
 253
 254 static struct platform_driver s3_wmi_driver = {
 255         .driver = {
 256                 .name = "surface3-wmi",
 257                 .pm = &s3_wmi_pm,
 258         },
 259         .remove = s3_wmi_remove,
 260 };
 261
 262 static int __init s3_wmi_init(void)
 263 {
 264         int error;
 265
 266         s3_wmi_pdev = platform_device_alloc("surface3-wmi", -1);
 267         if (!s3_wmi_pdev)
 268                 return -ENOMEM;
 269
 270         error = platform_device_add(s3_wmi_pdev);
 271         if (error)
 272                 goto err_device_put;
 273
 274         error = platform_driver_probe(&s3_wmi_driver, s3_wmi_probe);
 275         if (error)
 276                 goto err_device_del;
 277
 278         pr_info("Surface 3 WMI Extras loaded\n");
 279         return 0;
 280
 281  err_device_del:
 282         platform_device_del(s3_wmi_pdev);
 283  err_device_put:
 284         platform_device_put(s3_wmi_pdev);
 285         return error;
 286 }
 287
 288 static void __exit s3_wmi_exit(void)
 289 {
 290         platform_device_unregister(s3_wmi_pdev);
 291         platform_driver_unregister(&s3_wmi_driver);
 292 }
 293
 294 module_init(s3_wmi_init);
 295 module_exit(s3_wmi_exit);