drivers/input/misc/soc_button_array.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Supports for the button array on SoC tablets originally running
   4  * Windows 8.
   5  *
   6  * (C) Copyright 2014 Intel Corporation
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/input.h>
  11 #include <linux/init.h>
  12 #include <linux/kernel.h>
  13 #include <linux/acpi.h>
  14 #include <linux/gpio/consumer.h>
  15 #include <linux/gpio_keys.h>
  16 #include <linux/gpio.h>
  17 #include <linux/platform_device.h>
  18
  19 struct soc_button_info {
  20         const char *name;
  21         int acpi_index;
  22         unsigned int event_type;
  23         unsigned int event_code;
  24         bool autorepeat;
  25         bool wakeup;
  26 };
  27
  28 struct soc_device_data {
  29         const struct soc_button_info *button_info;
  30         int (*check)(struct device *dev);
  31 };
  32
  33 /*
  34  * Some of the buttons like volume up/down are auto repeat, while others
  35  * are not. To support both, we register two platform devices, and put
  36  * buttons into them based on whether the key should be auto repeat.
  37  */
  38 #define BUTTON_TYPES    2
  39
  40 struct soc_button_data {
  41         struct platform_device *children[BUTTON_TYPES];
  42 };
  43
  44 /*
  45  * Get the Nth GPIO number from the ACPI object.
  46  */
  47 static int soc_button_lookup_gpio(struct device *dev, int acpi_index)
  48 {
  49         struct gpio_desc *desc;
  50         int gpio;
  51
  52         desc = gpiod_get_index(dev, NULL, acpi_index, GPIOD_ASIS);
  53         if (IS_ERR(desc))
  54                 return PTR_ERR(desc);
  55
  56         gpio = desc_to_gpio(desc);
  57
  58         gpiod_put(desc);
  59
  60         return gpio;
  61 }
  62
  63 static struct platform_device *
  64 soc_button_device_create(struct platform_device *pdev,
  65                          const struct soc_button_info *button_info,
  66                          bool autorepeat)
  67 {
  68         const struct soc_button_info *info;
  69         struct platform_device *pd;
  70         struct gpio_keys_button *gpio_keys;
  71         struct gpio_keys_platform_data *gpio_keys_pdata;
  72         int n_buttons = 0;
  73         int gpio;
  74         int error;
  75
  76         for (info = button_info; info->name; info++)
  77                 if (info->autorepeat == autorepeat)
  78                         n_buttons++;
  79
  80         gpio_keys_pdata = devm_kzalloc(&pdev->dev,
  81                                        sizeof(*gpio_keys_pdata) +
  82                                         sizeof(*gpio_keys) * n_buttons,
  83                                        GFP_KERNEL);
  84         if (!gpio_keys_pdata)
  85                 return ERR_PTR(-ENOMEM);
  86
  87         gpio_keys = (void *)(gpio_keys_pdata + 1);
  88         n_buttons = 0;
  89
  90         for (info = button_info; info->name; info++) {
  91                 if (info->autorepeat != autorepeat)
  92                         continue;
  93
  94                 gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
  95                 if (!gpio_is_valid(gpio)) {
  96                         /*
  97                          * Skip GPIO if not present. Note we deliberately
  98                          * ignore -EPROBE_DEFER errors here. On some devices
  99                          * Intel is using so called virtual GPIOs which are not
 100                          * GPIOs at all but some way for AML code to check some
 101                          * random status bits without need a custom opregion.
 102                          * In some cases the resources table we parse points to
 103                          * such a virtual GPIO, since these are not real GPIOs
 104                          * we do not have a driver for these so they will never
 105                          * show up, therefore we ignore -EPROBE_DEFER.
 106                          */
 107                         continue;
 108                 }
 109
 110                 gpio_keys[n_buttons].type = info->event_type;
 111                 gpio_keys[n_buttons].code = info->event_code;
 112                 gpio_keys[n_buttons].gpio = gpio;
 113                 gpio_keys[n_buttons].active_low = 1;
 114                 gpio_keys[n_buttons].desc = info->name;
 115                 gpio_keys[n_buttons].wakeup = info->wakeup;
 116                 /* These devices often use cheap buttons, use 50 ms debounce */
 117                 gpio_keys[n_buttons].debounce_interval = 50;
 118                 n_buttons++;
 119         }
 120
 121         if (n_buttons == 0) {
 122                 error = -ENODEV;
 123                 goto err_free_mem;
 124         }
 125
 126         gpio_keys_pdata->buttons = gpio_keys;
 127         gpio_keys_pdata->nbuttons = n_buttons;
 128         gpio_keys_pdata->rep = autorepeat;
 129
 130         pd = platform_device_register_resndata(&pdev->dev, "gpio-keys",
 131                                                PLATFORM_DEVID_AUTO, NULL, 0,
 132                                                gpio_keys_pdata,
 133                                                sizeof(*gpio_keys_pdata));
 134         error = PTR_ERR_OR_ZERO(pd);
 135         if (error) {
 136                 dev_err(&pdev->dev,
 137                         "failed registering gpio-keys: %d\n", error);
 138                 goto err_free_mem;
 139         }
 140
 141         return pd;
 142
 143 err_free_mem:
 144         devm_kfree(&pdev->dev, gpio_keys_pdata);
 145         return ERR_PTR(error);
 146 }
 147
 148 static int soc_button_get_acpi_object_int(const union acpi_object *obj)
 149 {
 150         if (obj->type != ACPI_TYPE_INTEGER)
 151                 return -1;
 152
 153         return obj->integer.value;
 154 }
 155
 156 /* Parse a single ACPI0011 _DSD button descriptor */
 157 static int soc_button_parse_btn_desc(struct device *dev,
 158                                      const union acpi_object *desc,
 159                                      int collection_uid,
 160                                      struct soc_button_info *info)
 161 {
 162         int upage, usage;
 163
 164         if (desc->type != ACPI_TYPE_PACKAGE ||
 165             desc->package.count != 5 ||
 166             /* First byte should be 1 (control) */
 167             soc_button_get_acpi_object_int(&desc->package.elements[0]) != 1 ||
 168             /* Third byte should be collection uid */
 169             soc_button_get_acpi_object_int(&desc->package.elements[2]) !=
 170                                                             collection_uid) {
 171                 dev_err(dev, "Invalid ACPI Button Descriptor\n");
 172                 return -ENODEV;
 173         }
 174
 175         info->event_type = EV_KEY;
 176         info->acpi_index =
 177                 soc_button_get_acpi_object_int(&desc->package.elements[1]);
 178         upage = soc_button_get_acpi_object_int(&desc->package.elements[3]);
 179         usage = soc_button_get_acpi_object_int(&desc->package.elements[4]);
 180
 181         /*
 182          * The UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e descriptors use HID
 183          * usage page and usage codes, but otherwise the device is not HID
 184          * compliant: it uses one irq per button instead of generating HID
 185          * input reports and some buttons should generate wakeups where as
 186          * others should not, so we cannot use the HID subsystem.
 187          *
 188          * Luckily all devices only use a few usage page + usage combinations,
 189          * so we can simply check for the known combinations here.
 190          */
 191         if (upage == 0x01 && usage == 0x81) {
 192                 info->name = "power";
 193                 info->event_code = KEY_POWER;
 194                 info->wakeup = true;
 195         } else if (upage == 0x01 && usage == 0xca) {
 196                 info->name = "rotation lock switch";
 197                 info->event_type = EV_SW;
 198                 info->event_code = SW_ROTATE_LOCK;
 199         } else if (upage == 0x07 && usage == 0xe3) {
 200                 info->name = "home";
 201                 info->event_code = KEY_LEFTMETA;
 202                 info->wakeup = true;
 203         } else if (upage == 0x0c && usage == 0xe9) {
 204                 info->name = "volume_up";
 205                 info->event_code = KEY_VOLUMEUP;
 206                 info->autorepeat = true;
 207         } else if (upage == 0x0c && usage == 0xea) {
 208                 info->name = "volume_down";
 209                 info->event_code = KEY_VOLUMEDOWN;
 210                 info->autorepeat = true;
 211         } else {
 212                 dev_warn(dev, "Unknown button index %d upage %02x usage %02x, ignoring\n",
 213                          info->acpi_index, upage, usage);
 214                 info->name = "unknown";
 215                 info->event_code = KEY_RESERVED;
 216         }
 217
 218         return 0;
 219 }
 220
 221 /* ACPI0011 _DSD btns descriptors UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e */
 222 static const u8 btns_desc_uuid[16] = {
 223         0x25, 0xd6, 0x6b, 0xfa, 0xe8, 0x9c, 0x0d, 0x47,
 224         0xa2, 0xc7, 0xb3, 0xca, 0x36, 0xc4, 0x28, 0x2e
 225 };
 226
 227 /* Parse ACPI0011 _DSD button descriptors */
 228 static struct soc_button_info *soc_button_get_button_info(struct device *dev)
 229 {
 230         struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
 231         const union acpi_object *desc, *el0, *uuid, *btns_desc = NULL;
 232         struct soc_button_info *button_info;
 233         acpi_status status;
 234         int i, btn, collection_uid = -1;
 235
 236         status = acpi_evaluate_object_typed(ACPI_HANDLE(dev), "_DSD", NULL,
 237                                             &buf, ACPI_TYPE_PACKAGE);
 238         if (ACPI_FAILURE(status)) {
 239                 dev_err(dev, "ACPI _DSD object not found\n");
 240                 return ERR_PTR(-ENODEV);
 241         }
 242
 243         /* Look for the Button Descriptors UUID */
 244         desc = buf.pointer;
 245         for (i = 0; (i + 1) < desc->package.count; i += 2) {
 246                 uuid = &desc->package.elements[i];
 247
 248                 if (uuid->type != ACPI_TYPE_BUFFER ||
 249                     uuid->buffer.length != 16 ||
 250                     desc->package.elements[i + 1].type != ACPI_TYPE_PACKAGE) {
 251                         break;
 252                 }
 253
 254                 if (memcmp(uuid->buffer.pointer, btns_desc_uuid, 16) == 0) {
 255                         btns_desc = &desc->package.elements[i + 1];
 256                         break;
 257                 }
 258         }
 259
 260         if (!btns_desc) {
 261                 dev_err(dev, "ACPI Button Descriptors not found\n");
 262                 button_info = ERR_PTR(-ENODEV);
 263                 goto out;
 264         }
 265
 266         /* The first package describes the collection */
 267         el0 = &btns_desc->package.elements[0];
 268         if (el0->type == ACPI_TYPE_PACKAGE &&
 269             el0->package.count == 5 &&
 270             /* First byte should be 0 (collection) */
 271             soc_button_get_acpi_object_int(&el0->package.elements[0]) == 0 &&
 272             /* Third byte should be 0 (top level collection) */
 273             soc_button_get_acpi_object_int(&el0->package.elements[2]) == 0) {
 274                 collection_uid = soc_button_get_acpi_object_int(
 275                                                 &el0->package.elements[1]);
 276         }
 277         if (collection_uid == -1) {
 278                 dev_err(dev, "Invalid Button Collection Descriptor\n");
 279                 button_info = ERR_PTR(-ENODEV);
 280                 goto out;
 281         }
 282
 283         /* There are package.count - 1 buttons + 1 terminating empty entry */
 284         button_info = devm_kcalloc(dev, btns_desc->package.count,
 285                                    sizeof(*button_info), GFP_KERNEL);
 286         if (!button_info) {
 287                 button_info = ERR_PTR(-ENOMEM);
 288                 goto out;
 289         }
 290
 291         /* Parse the button descriptors */
 292         for (i = 1, btn = 0; i < btns_desc->package.count; i++, btn++) {
 293                 if (soc_button_parse_btn_desc(dev,
 294                                               &btns_desc->package.elements[i],
 295                                               collection_uid,
 296                                               &button_info[btn])) {
 297                         button_info = ERR_PTR(-ENODEV);
 298                         goto out;
 299                 }
 300         }
 301
 302 out:
 303         kfree(buf.pointer);
 304         return button_info;
 305 }
 306
 307 static int soc_button_remove(struct platform_device *pdev)
 308 {
 309         struct soc_button_data *priv = platform_get_drvdata(pdev);
 310
 311         int i;
 312
 313         for (i = 0; i < BUTTON_TYPES; i++)
 314                 if (priv->children[i])
 315                         platform_device_unregister(priv->children[i]);
 316
 317         return 0;
 318 }
 319
 320 static int soc_button_probe(struct platform_device *pdev)
 321 {
 322         struct device *dev = &pdev->dev;
 323         const struct soc_device_data *device_data;
 324         const struct soc_button_info *button_info;
 325         struct soc_button_data *priv;
 326         struct platform_device *pd;
 327         int i;
 328         int error;
 329
 330         device_data = acpi_device_get_match_data(dev);
 331         if (device_data && device_data->check) {
 332                 error = device_data->check(dev);
 333                 if (error)
 334                         return error;
 335         }
 336
 337         if (device_data && device_data->button_info) {
 338                 button_info = device_data->button_info;
 339         } else {
 340                 button_info = soc_button_get_button_info(dev);
 341                 if (IS_ERR(button_info))
 342                         return PTR_ERR(button_info);
 343         }
 344
 345         error = gpiod_count(dev, NULL);
 346         if (error < 0) {
 347                 dev_dbg(dev, "no GPIO attached, ignoring...\n");
 348                 return -ENODEV;
 349         }
 350
 351         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 352         if (!priv)
 353                 return -ENOMEM;
 354
 355         platform_set_drvdata(pdev, priv);
 356
 357         for (i = 0; i < BUTTON_TYPES; i++) {
 358                 pd = soc_button_device_create(pdev, button_info, i == 0);
 359                 if (IS_ERR(pd)) {
 360                         error = PTR_ERR(pd);
 361                         if (error != -ENODEV) {
 362                                 soc_button_remove(pdev);
 363                                 return error;
 364                         }
 365                         continue;
 366                 }
 367
 368                 priv->children[i] = pd;
 369         }
 370
 371         if (!priv->children[0] && !priv->children[1])
 372                 return -ENODEV;
 373
 374         if (!device_data || !device_data->button_info)
 375                 devm_kfree(dev, button_info);
 376
 377         return 0;
 378 }
 379
 380 /*
 381  * Definition of buttons on the tablet. The ACPI index of each button
 382  * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
 383  * Platforms"
 384  */
 385 static const struct soc_button_info soc_button_PNP0C40[] = {
 386         { "power", 0, EV_KEY, KEY_POWER, false, true },
 387         { "home", 1, EV_KEY, KEY_LEFTMETA, false, true },
 388         { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
 389         { "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false },
 390         { "rotation_lock", 4, EV_KEY, KEY_ROTATE_LOCK_TOGGLE, false, false },
 391         { }
 392 };
 393
 394 static const struct soc_device_data soc_device_PNP0C40 = {
 395         .button_info = soc_button_PNP0C40,
 396 };
 397
 398 /*
 399  * Special device check for Surface Book 2 and Surface Pro (2017).
 400  * Both, the Surface Pro 4 (surfacepro3_button.c) and the above mentioned
 401  * devices use MSHW0040 for power and volume buttons, however the way they
 402  * have to be addressed differs. Make sure that we only load this drivers
 403  * for the correct devices by checking the OEM Platform Revision provided by
 404  * the _DSM method.
 405  */
 406 #define MSHW0040_DSM_REVISION           0x01
 407 #define MSHW0040_DSM_GET_OMPR           0x02    // get OEM Platform Revision
 408 static const guid_t MSHW0040_DSM_UUID =
 409         GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65,
 410                   0x49, 0x80, 0x35);
 411
 412 static int soc_device_check_MSHW0040(struct device *dev)
 413 {
 414         acpi_handle handle = ACPI_HANDLE(dev);
 415         union acpi_object *result;
 416         u64 oem_platform_rev = 0;       // valid revisions are nonzero
 417
 418         // get OEM platform revision
 419         result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID,
 420                                          MSHW0040_DSM_REVISION,
 421                                          MSHW0040_DSM_GET_OMPR, NULL,
 422                                          ACPI_TYPE_INTEGER);
 423
 424         if (result) {
 425                 oem_platform_rev = result->integer.value;
 426                 ACPI_FREE(result);
 427         }
 428
 429         /*
 430          * If the revision is zero here, the _DSM evaluation has failed. This
 431          * indicates that we have a Pro 4 or Book 1 and this driver should not
 432          * be used.
 433          */
 434         if (oem_platform_rev == 0)
 435                 return -ENODEV;
 436
 437         dev_dbg(dev, "OEM Platform Revision %llu\n", oem_platform_rev);
 438
 439         return 0;
 440 }
 441
 442 /*
 443  * Button infos for Microsoft Surface Book 2 and Surface Pro (2017).
 444  * Obtained from DSDT/testing.
 445  */
 446 static const struct soc_button_info soc_button_MSHW0040[] = {
 447         { "power", 0, EV_KEY, KEY_POWER, false, true },
 448         { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
 449         { "volume_down", 4, EV_KEY, KEY_VOLUMEDOWN, true, false },
 450         { }
 451 };
 452
 453 static const struct soc_device_data soc_device_MSHW0040 = {
 454         .button_info = soc_button_MSHW0040,
 455         .check = soc_device_check_MSHW0040,
 456 };
 457
 458 static const struct acpi_device_id soc_button_acpi_match[] = {
 459         { "PNP0C40", (unsigned long)&soc_device_PNP0C40 },
 460         { "ACPI0011", 0 },
 461
 462         /* Microsoft Surface Devices (5th and 6th generation) */
 463         { "MSHW0040", (unsigned long)&soc_device_MSHW0040 },
 464
 465         { }
 466 };
 467
 468 MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match);
 469
 470 static struct platform_driver soc_button_driver = {
 471         .probe          = soc_button_probe,
 472         .remove         = soc_button_remove,
 473         .driver         = {
 474                 .name = KBUILD_MODNAME,
 475                 .acpi_match_table = ACPI_PTR(soc_button_acpi_match),
 476         },
 477 };
 478 module_platform_driver(soc_button_driver);
 479
 480 MODULE_LICENSE("GPL");