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 /*
  29  * Some of the buttons like volume up/down are auto repeat, while others
  30  * are not. To support both, we register two platform devices, and put
  31  * buttons into them based on whether the key should be auto repeat.
  32  */
  33 #define BUTTON_TYPES    2
  34
  35 struct soc_button_data {
  36         struct platform_device *children[BUTTON_TYPES];
  37 };
  38
  39 /*
  40  * Get the Nth GPIO number from the ACPI object.
  41  */
  42 static int soc_button_lookup_gpio(struct device *dev, int acpi_index)
  43 {
  44         struct gpio_desc *desc;
  45         int gpio;
  46
  47         desc = gpiod_get_index(dev, NULL, acpi_index, GPIOD_ASIS);
  48         if (IS_ERR(desc))
  49                 return PTR_ERR(desc);
  50
  51         gpio = desc_to_gpio(desc);
  52
  53         gpiod_put(desc);
  54
  55         return gpio;
  56 }
  57
  58 static struct platform_device *
  59 soc_button_device_create(struct platform_device *pdev,
  60                          const struct soc_button_info *button_info,
  61                          bool autorepeat)
  62 {
  63         const struct soc_button_info *info;
  64         struct platform_device *pd;
  65         struct gpio_keys_button *gpio_keys;
  66         struct gpio_keys_platform_data *gpio_keys_pdata;
  67         int n_buttons = 0;
  68         int gpio;
  69         int error;
  70
  71         for (info = button_info; info->name; info++)
  72                 if (info->autorepeat == autorepeat)
  73                         n_buttons++;
  74
  75         gpio_keys_pdata = devm_kzalloc(&pdev->dev,
  76                                        sizeof(*gpio_keys_pdata) +
  77                                         sizeof(*gpio_keys) * n_buttons,
  78                                        GFP_KERNEL);
  79         if (!gpio_keys_pdata)
  80                 return ERR_PTR(-ENOMEM);
  81
  82         gpio_keys = (void *)(gpio_keys_pdata + 1);
  83         n_buttons = 0;
  84
  85         for (info = button_info; info->name; info++) {
  86                 if (info->autorepeat != autorepeat)
  87                         continue;
  88
  89                 gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
  90                 if (!gpio_is_valid(gpio))
  91                         continue;
  92
  93                 gpio_keys[n_buttons].type = info->event_type;
  94                 gpio_keys[n_buttons].code = info->event_code;
  95                 gpio_keys[n_buttons].gpio = gpio;
  96                 gpio_keys[n_buttons].active_low = 1;
  97                 gpio_keys[n_buttons].desc = info->name;
  98                 gpio_keys[n_buttons].wakeup = info->wakeup;
  99                 /* These devices often use cheap buttons, use 50 ms debounce */
 100                 gpio_keys[n_buttons].debounce_interval = 50;
 101                 n_buttons++;
 102         }
 103
 104         if (n_buttons == 0) {
 105                 error = -ENODEV;
 106                 goto err_free_mem;
 107         }
 108
 109         gpio_keys_pdata->buttons = gpio_keys;
 110         gpio_keys_pdata->nbuttons = n_buttons;
 111         gpio_keys_pdata->rep = autorepeat;
 112
 113         pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO);
 114         if (!pd) {
 115                 error = -ENOMEM;
 116                 goto err_free_mem;
 117         }
 118
 119         error = platform_device_add_data(pd, gpio_keys_pdata,
 120                                          sizeof(*gpio_keys_pdata));
 121         if (error)
 122                 goto err_free_pdev;
 123
 124         error = platform_device_add(pd);
 125         if (error)
 126                 goto err_free_pdev;
 127
 128         return pd;
 129
 130 err_free_pdev:
 131         platform_device_put(pd);
 132 err_free_mem:
 133         devm_kfree(&pdev->dev, gpio_keys_pdata);
 134         return ERR_PTR(error);
 135 }
 136
 137 static int soc_button_get_acpi_object_int(const union acpi_object *obj)
 138 {
 139         if (obj->type != ACPI_TYPE_INTEGER)
 140                 return -1;
 141
 142         return obj->integer.value;
 143 }
 144
 145 /* Parse a single ACPI0011 _DSD button descriptor */
 146 static int soc_button_parse_btn_desc(struct device *dev,
 147                                      const union acpi_object *desc,
 148                                      int collection_uid,
 149                                      struct soc_button_info *info)
 150 {
 151         int upage, usage;
 152
 153         if (desc->type != ACPI_TYPE_PACKAGE ||
 154             desc->package.count != 5 ||
 155             /* First byte should be 1 (control) */
 156             soc_button_get_acpi_object_int(&desc->package.elements[0]) != 1 ||
 157             /* Third byte should be collection uid */
 158             soc_button_get_acpi_object_int(&desc->package.elements[2]) !=
 159                                                             collection_uid) {
 160                 dev_err(dev, "Invalid ACPI Button Descriptor\n");
 161                 return -ENODEV;
 162         }
 163
 164         info->event_type = EV_KEY;
 165         info->acpi_index =
 166                 soc_button_get_acpi_object_int(&desc->package.elements[1]);
 167         upage = soc_button_get_acpi_object_int(&desc->package.elements[3]);
 168         usage = soc_button_get_acpi_object_int(&desc->package.elements[4]);
 169
 170         /*
 171          * The UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e descriptors use HID
 172          * usage page and usage codes, but otherwise the device is not HID
 173          * compliant: it uses one irq per button instead of generating HID
 174          * input reports and some buttons should generate wakeups where as
 175          * others should not, so we cannot use the HID subsystem.
 176          *
 177          * Luckily all devices only use a few usage page + usage combinations,
 178          * so we can simply check for the known combinations here.
 179          */
 180         if (upage == 0x01 && usage == 0x81) {
 181                 info->name = "power";
 182                 info->event_code = KEY_POWER;
 183                 info->wakeup = true;
 184         } else if (upage == 0x01 && usage == 0xca) {
 185                 info->name = "rotation lock switch";
 186                 info->event_type = EV_SW;
 187                 info->event_code = SW_ROTATE_LOCK;
 188         } else if (upage == 0x07 && usage == 0xe3) {
 189                 info->name = "home";
 190                 info->event_code = KEY_LEFTMETA;
 191                 info->wakeup = true;
 192         } else if (upage == 0x0c && usage == 0xe9) {
 193                 info->name = "volume_up";
 194                 info->event_code = KEY_VOLUMEUP;
 195                 info->autorepeat = true;
 196         } else if (upage == 0x0c && usage == 0xea) {
 197                 info->name = "volume_down";
 198                 info->event_code = KEY_VOLUMEDOWN;
 199                 info->autorepeat = true;
 200         } else {
 201                 dev_warn(dev, "Unknown button index %d upage %02x usage %02x, ignoring\n",
 202                          info->acpi_index, upage, usage);
 203                 info->name = "unknown";
 204                 info->event_code = KEY_RESERVED;
 205         }
 206
 207         return 0;
 208 }
 209
 210 /* ACPI0011 _DSD btns descriptors UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e */
 211 static const u8 btns_desc_uuid[16] = {
 212         0x25, 0xd6, 0x6b, 0xfa, 0xe8, 0x9c, 0x0d, 0x47,
 213         0xa2, 0xc7, 0xb3, 0xca, 0x36, 0xc4, 0x28, 0x2e
 214 };
 215
 216 /* Parse ACPI0011 _DSD button descriptors */
 217 static struct soc_button_info *soc_button_get_button_info(struct device *dev)
 218 {
 219         struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
 220         const union acpi_object *desc, *el0, *uuid, *btns_desc = NULL;
 221         struct soc_button_info *button_info;
 222         acpi_status status;
 223         int i, btn, collection_uid = -1;
 224
 225         status = acpi_evaluate_object_typed(ACPI_HANDLE(dev), "_DSD", NULL,
 226                                             &buf, ACPI_TYPE_PACKAGE);
 227         if (ACPI_FAILURE(status)) {
 228                 dev_err(dev, "ACPI _DSD object not found\n");
 229                 return ERR_PTR(-ENODEV);
 230         }
 231
 232         /* Look for the Button Descriptors UUID */
 233         desc = buf.pointer;
 234         for (i = 0; (i + 1) < desc->package.count; i += 2) {
 235                 uuid = &desc->package.elements[i];
 236
 237                 if (uuid->type != ACPI_TYPE_BUFFER ||
 238                     uuid->buffer.length != 16 ||
 239                     desc->package.elements[i + 1].type != ACPI_TYPE_PACKAGE) {
 240                         break;
 241                 }
 242
 243                 if (memcmp(uuid->buffer.pointer, btns_desc_uuid, 16) == 0) {
 244                         btns_desc = &desc->package.elements[i + 1];
 245                         break;
 246                 }
 247         }
 248
 249         if (!btns_desc) {
 250                 dev_err(dev, "ACPI Button Descriptors not found\n");
 251                 button_info = ERR_PTR(-ENODEV);
 252                 goto out;
 253         }
 254
 255         /* The first package describes the collection */
 256         el0 = &btns_desc->package.elements[0];
 257         if (el0->type == ACPI_TYPE_PACKAGE &&
 258             el0->package.count == 5 &&
 259             /* First byte should be 0 (collection) */
 260             soc_button_get_acpi_object_int(&el0->package.elements[0]) == 0 &&
 261             /* Third byte should be 0 (top level collection) */
 262             soc_button_get_acpi_object_int(&el0->package.elements[2]) == 0) {
 263                 collection_uid = soc_button_get_acpi_object_int(
 264                                                 &el0->package.elements[1]);
 265         }
 266         if (collection_uid == -1) {
 267                 dev_err(dev, "Invalid Button Collection Descriptor\n");
 268                 button_info = ERR_PTR(-ENODEV);
 269                 goto out;
 270         }
 271
 272         /* There are package.count - 1 buttons + 1 terminating empty entry */
 273         button_info = devm_kcalloc(dev, btns_desc->package.count,
 274                                    sizeof(*button_info), GFP_KERNEL);
 275         if (!button_info) {
 276                 button_info = ERR_PTR(-ENOMEM);
 277                 goto out;
 278         }
 279
 280         /* Parse the button descriptors */
 281         for (i = 1, btn = 0; i < btns_desc->package.count; i++, btn++) {
 282                 if (soc_button_parse_btn_desc(dev,
 283                                               &btns_desc->package.elements[i],
 284                                               collection_uid,
 285                                               &button_info[btn])) {
 286                         button_info = ERR_PTR(-ENODEV);
 287                         goto out;
 288                 }
 289         }
 290
 291 out:
 292         kfree(buf.pointer);
 293         return button_info;
 294 }
 295
 296 static int soc_button_remove(struct platform_device *pdev)
 297 {
 298         struct soc_button_data *priv = platform_get_drvdata(pdev);
 299
 300         int i;
 301
 302         for (i = 0; i < BUTTON_TYPES; i++)
 303                 if (priv->children[i])
 304                         platform_device_unregister(priv->children[i]);
 305
 306         return 0;
 307 }
 308
 309 static int soc_button_probe(struct platform_device *pdev)
 310 {
 311         struct device *dev = &pdev->dev;
 312         const struct acpi_device_id *id;
 313         struct soc_button_info *button_info;
 314         struct soc_button_data *priv;
 315         struct platform_device *pd;
 316         int i;
 317         int error;
 318
 319         id = acpi_match_device(dev->driver->acpi_match_table, dev);
 320         if (!id)
 321                 return -ENODEV;
 322
 323         if (!id->driver_data) {
 324                 button_info = soc_button_get_button_info(dev);
 325                 if (IS_ERR(button_info))
 326                         return PTR_ERR(button_info);
 327         } else {
 328                 button_info = (struct soc_button_info *)id->driver_data;
 329         }
 330
 331         error = gpiod_count(dev, NULL);
 332         if (error < 0) {
 333                 dev_dbg(dev, "no GPIO attached, ignoring...\n");
 334                 return -ENODEV;
 335         }
 336
 337         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 338         if (!priv)
 339                 return -ENOMEM;
 340
 341         platform_set_drvdata(pdev, priv);
 342
 343         for (i = 0; i < BUTTON_TYPES; i++) {
 344                 pd = soc_button_device_create(pdev, button_info, i == 0);
 345                 if (IS_ERR(pd)) {
 346                         error = PTR_ERR(pd);
 347                         if (error != -ENODEV) {
 348                                 soc_button_remove(pdev);
 349                                 return error;
 350                         }
 351                         continue;
 352                 }
 353
 354                 priv->children[i] = pd;
 355         }
 356
 357         if (!priv->children[0] && !priv->children[1])
 358                 return -ENODEV;
 359
 360         if (!id->driver_data)
 361                 devm_kfree(dev, button_info);
 362
 363         return 0;
 364 }
 365
 366 /*
 367  * Definition of buttons on the tablet. The ACPI index of each button
 368  * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
 369  * Platforms"
 370  */
 371 static struct soc_button_info soc_button_PNP0C40[] = {
 372         { "power", 0, EV_KEY, KEY_POWER, false, true },
 373         { "home", 1, EV_KEY, KEY_LEFTMETA, false, true },
 374         { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
 375         { "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false },
 376         { "rotation_lock", 4, EV_KEY, KEY_ROTATE_LOCK_TOGGLE, false, false },
 377         { }
 378 };
 379
 380 static const struct acpi_device_id soc_button_acpi_match[] = {
 381         { "PNP0C40", (unsigned long)soc_button_PNP0C40 },
 382         { "ACPI0011", 0 },
 383         { }
 384 };
 385
 386 MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match);
 387
 388 static struct platform_driver soc_button_driver = {
 389         .probe          = soc_button_probe,
 390         .remove         = soc_button_remove,
 391         .driver         = {
 392                 .name = KBUILD_MODNAME,
 393                 .acpi_match_table = ACPI_PTR(soc_button_acpi_match),
 394         },
 395 };
 396 module_platform_driver(soc_button_driver);
 397
 398 MODULE_LICENSE("GPL");