linux/drivers/platform/x86/surface3-wmi.c
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   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
  24MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@redhat.com>");
  25MODULE_DESCRIPTION("Surface 3 platform driver");
  26MODULE_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
  34MODULE_ALIAS("wmi:" SURFACE3_LID_GUID);
  35
  36static 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
  48struct 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
  55static struct platform_device *s3_wmi_pdev;
  56
  57static struct surface3_wmi s3_wmi;
  58
  59static DEFINE_MUTEX(s3_wmi_lock);
  60
  61static 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
  90static inline int s3_wmi_query_lid(int *ret)
  91{
  92        return s3_wmi_query_block(SURFACE3_LID_GUID, 0, ret);
  93}
  94
  95static 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
 109static int s3_wmi_hp_notify(struct acpi_device *adev, u32 value)
 110{
 111        return s3_wmi_send_lid_state();
 112}
 113
 114static 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
 140static 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
 176static 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
 204static 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
 237static 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
 247static int __maybe_unused s3_wmi_resume(struct device *dev)
 248{
 249        s3_wmi_send_lid_state();
 250        return 0;
 251}
 252static SIMPLE_DEV_PM_OPS(s3_wmi_pm, NULL, s3_wmi_resume);
 253
 254static 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
 262static 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
 288static void __exit s3_wmi_exit(void)
 289{
 290        platform_device_unregister(s3_wmi_pdev);
 291        platform_driver_unregister(&s3_wmi_driver);
 292}
 293
 294module_init(s3_wmi_init);
 295module_exit(s3_wmi_exit);
 296