drivers/input/misc/soc_button_array.c

   1 /*
   2  * Supports for the button array on SoC tablets originally running
   3  * Windows 8.
   4  *
   5  * (C) Copyright 2014 Intel Corporation
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; version 2
  10  * of the License.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/input.h>
  15 #include <linux/init.h>
  16 #include <linux/kernel.h>
  17 #include <linux/acpi.h>
  18 #include <linux/gpio/consumer.h>
  19 #include <linux/gpio_keys.h>
  20 #include <linux/gpio.h>
  21 #include <linux/platform_device.h>
  22
  23 struct soc_button_info {
  24         const char *name;
  25         int acpi_index;
  26         unsigned int event_type;
  27         unsigned int event_code;
  28         bool autorepeat;
  29         bool wakeup;
  30 };
  31
  32 /*
  33  * Some of the buttons like volume up/down are auto repeat, while others
  34  * are not. To support both, we register two platform devices, and put
  35  * buttons into them based on whether the key should be auto repeat.
  36  */
  37 #define BUTTON_TYPES    2
  38
  39 struct soc_button_data {
  40         struct platform_device *children[BUTTON_TYPES];
  41 };
  42
  43 /*
  44  * Get the Nth GPIO number from the ACPI object.
  45  */
  46 static int soc_button_lookup_gpio(struct device *dev, int acpi_index)
  47 {
  48         struct gpio_desc *desc;
  49         int gpio;
  50
  51         desc = gpiod_get_index(dev, NULL, acpi_index, GPIOD_ASIS);
  52         if (IS_ERR(desc))
  53                 return PTR_ERR(desc);
  54
  55         gpio = desc_to_gpio(desc);
  56
  57         gpiod_put(desc);
  58
  59         return gpio;
  60 }
  61
  62 static struct platform_device *
  63 soc_button_device_create(struct platform_device *pdev,
  64                          const struct soc_button_info *button_info,
  65                          bool autorepeat)
  66 {
  67         const struct soc_button_info *info;
  68         struct platform_device *pd;
  69         struct gpio_keys_button *gpio_keys;
  70         struct gpio_keys_platform_data *gpio_keys_pdata;
  71         int n_buttons = 0;
  72         int gpio;
  73         int error;
  74
  75         for (info = button_info; info->name; info++)
  76                 if (info->autorepeat == autorepeat)
  77                         n_buttons++;
  78
  79         gpio_keys_pdata = devm_kzalloc(&pdev->dev,
  80                                        sizeof(*gpio_keys_pdata) +
  81                                         sizeof(*gpio_keys) * n_buttons,
  82                                        GFP_KERNEL);
  83         if (!gpio_keys_pdata)
  84                 return ERR_PTR(-ENOMEM);
  85
  86         gpio_keys = (void *)(gpio_keys_pdata + 1);
  87         n_buttons = 0;
  88
  89         for (info = button_info; info->name; info++) {
  90                 if (info->autorepeat != autorepeat)
  91                         continue;
  92
  93                 gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index);
  94                 if (!gpio_is_valid(gpio))
  95                         continue;
  96
  97                 gpio_keys[n_buttons].type = info->event_type;
  98                 gpio_keys[n_buttons].code = info->event_code;
  99                 gpio_keys[n_buttons].gpio = gpio;
 100                 gpio_keys[n_buttons].active_low = 1;
 101                 gpio_keys[n_buttons].desc = info->name;
 102                 gpio_keys[n_buttons].wakeup = info->wakeup;
 103                 /* These devices often use cheap buttons, use 50 ms debounce */
 104                 gpio_keys[n_buttons].debounce_interval = 50;
 105                 n_buttons++;
 106         }
 107
 108         if (n_buttons == 0) {
 109                 error = -ENODEV;
 110                 goto err_free_mem;
 111         }
 112
 113         gpio_keys_pdata->buttons = gpio_keys;
 114         gpio_keys_pdata->nbuttons = n_buttons;
 115         gpio_keys_pdata->rep = autorepeat;
 116
 117         pd = platform_device_alloc("gpio-keys", PLATFORM_DEVID_AUTO);
 118         if (!pd) {
 119                 error = -ENOMEM;
 120                 goto err_free_mem;
 121         }
 122
 123         error = platform_device_add_data(pd, gpio_keys_pdata,
 124                                          sizeof(*gpio_keys_pdata));
 125         if (error)
 126                 goto err_free_pdev;
 127
 128         error = platform_device_add(pd);
 129         if (error)
 130                 goto err_free_pdev;
 131
 132         return pd;
 133
 134 err_free_pdev:
 135         platform_device_put(pd);
 136 err_free_mem:
 137         devm_kfree(&pdev->dev, gpio_keys_pdata);
 138         return ERR_PTR(error);
 139 }
 140
 141 static int soc_button_get_acpi_object_int(const union acpi_object *obj)
 142 {
 143         if (obj->type != ACPI_TYPE_INTEGER)
 144                 return -1;
 145
 146         return obj->integer.value;
 147 }
 148
 149 /* Parse a single ACPI0011 _DSD button descriptor */
 150 static int soc_button_parse_btn_desc(struct device *dev,
 151                                      const union acpi_object *desc,
 152                                      int collection_uid,
 153                                      struct soc_button_info *info)
 154 {
 155         int upage, usage;
 156
 157         if (desc->type != ACPI_TYPE_PACKAGE ||
 158             desc->package.count != 5 ||
 159             /* First byte should be 1 (control) */
 160             soc_button_get_acpi_object_int(&desc->package.elements[0]) != 1 ||
 161             /* Third byte should be collection uid */
 162             soc_button_get_acpi_object_int(&desc->package.elements[2]) !=
 163                                                             collection_uid) {
 164                 dev_err(dev, "Invalid ACPI Button Descriptor\n");
 165                 return -ENODEV;
 166         }
 167
 168         info->event_type = EV_KEY;
 169         info->acpi_index =
 170                 soc_button_get_acpi_object_int(&desc->package.elements[1]);
 171         upage = soc_button_get_acpi_object_int(&desc->package.elements[3]);
 172         usage = soc_button_get_acpi_object_int(&desc->package.elements[4]);
 173
 174         /*
 175          * The UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e descriptors use HID
 176          * usage page and usage codes, but otherwise the device is not HID
 177          * compliant: it uses one irq per button instead of generating HID
 178          * input reports and some buttons should generate wakeups where as
 179          * others should not, so we cannot use the HID subsystem.
 180          *
 181          * Luckily all devices only use a few usage page + usage combinations,
 182          * so we can simply check for the known combinations here.
 183          */
 184         if (upage == 0x01 && usage == 0x81) {
 185                 info->name = "power";
 186                 info->event_code = KEY_POWER;
 187                 info->wakeup = true;
 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                 return ERR_PTR(-ENODEV);
 252         }
 253
 254         /* The first package describes the collection */
 255         el0 = &btns_desc->package.elements[0];
 256         if (el0->type == ACPI_TYPE_PACKAGE &&
 257             el0->package.count == 5 &&
 258             /* First byte should be 0 (collection) */
 259             soc_button_get_acpi_object_int(&el0->package.elements[0]) == 0 &&
 260             /* Third byte should be 0 (top level collection) */
 261             soc_button_get_acpi_object_int(&el0->package.elements[2]) == 0) {
 262                 collection_uid = soc_button_get_acpi_object_int(
 263                                                 &el0->package.elements[1]);
 264         }
 265         if (collection_uid == -1) {
 266                 dev_err(dev, "Invalid Button Collection Descriptor\n");
 267                 return ERR_PTR(-ENODEV);
 268         }
 269
 270         /* There are package.count - 1 buttons + 1 terminating empty entry */
 271         button_info = devm_kcalloc(dev, btns_desc->package.count,
 272                                    sizeof(*button_info), GFP_KERNEL);
 273         if (!button_info)
 274                 return ERR_PTR(-ENOMEM);
 275
 276         /* Parse the button descriptors */
 277         for (i = 1, btn = 0; i < btns_desc->package.count; i++, btn++) {
 278                 if (soc_button_parse_btn_desc(dev,
 279                                               &btns_desc->package.elements[i],
 280                                               collection_uid,
 281                                               &button_info[btn]))
 282                         return ERR_PTR(-ENODEV);
 283         }
 284
 285         return button_info;
 286 }
 287
 288 static int soc_button_remove(struct platform_device *pdev)
 289 {
 290         struct soc_button_data *priv = platform_get_drvdata(pdev);
 291
 292         int i;
 293
 294         for (i = 0; i < BUTTON_TYPES; i++)
 295                 if (priv->children[i])
 296                         platform_device_unregister(priv->children[i]);
 297
 298         return 0;
 299 }
 300
 301 static int soc_button_probe(struct platform_device *pdev)
 302 {
 303         struct device *dev = &pdev->dev;
 304         const struct acpi_device_id *id;
 305         struct soc_button_info *button_info;
 306         struct soc_button_data *priv;
 307         struct platform_device *pd;
 308         int i;
 309         int error;
 310
 311         id = acpi_match_device(dev->driver->acpi_match_table, dev);
 312         if (!id)
 313                 return -ENODEV;
 314
 315         if (!id->driver_data) {
 316                 button_info = soc_button_get_button_info(dev);
 317                 if (IS_ERR(button_info))
 318                         return PTR_ERR(button_info);
 319         } else {
 320                 button_info = (struct soc_button_info *)id->driver_data;
 321         }
 322
 323         error = gpiod_count(dev, NULL);
 324         if (error < 0) {
 325                 dev_dbg(dev, "no GPIO attached, ignoring...\n");
 326                 return error;
 327         }
 328
 329         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 330         if (!priv)
 331                 return -ENOMEM;
 332
 333         platform_set_drvdata(pdev, priv);
 334
 335         for (i = 0; i < BUTTON_TYPES; i++) {
 336                 pd = soc_button_device_create(pdev, button_info, i == 0);
 337                 if (IS_ERR(pd)) {
 338                         error = PTR_ERR(pd);
 339                         if (error != -ENODEV) {
 340                                 soc_button_remove(pdev);
 341                                 return error;
 342                         }
 343                         continue;
 344                 }
 345
 346                 priv->children[i] = pd;
 347         }
 348
 349         if (!priv->children[0] && !priv->children[1])
 350                 return -ENODEV;
 351
 352         if (!id->driver_data)
 353                 devm_kfree(dev, button_info);
 354
 355         return 0;
 356 }
 357
 358 /*
 359  * Definition of buttons on the tablet. The ACPI index of each button
 360  * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC
 361  * Platforms"
 362  */
 363 static struct soc_button_info soc_button_PNP0C40[] = {
 364         { "power", 0, EV_KEY, KEY_POWER, false, true },
 365         { "home", 1, EV_KEY, KEY_LEFTMETA, false, true },
 366         { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false },
 367         { "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false },
 368         { "rotation_lock", 4, EV_SW, SW_ROTATE_LOCK, false, false },
 369         { }
 370 };
 371
 372 static const struct acpi_device_id soc_button_acpi_match[] = {
 373         { "PNP0C40", (unsigned long)soc_button_PNP0C40 },
 374         { "ACPI0011", 0 },
 375         { }
 376 };
 377
 378 MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match);
 379
 380 static struct platform_driver soc_button_driver = {
 381         .probe          = soc_button_probe,
 382         .remove         = soc_button_remove,
 383         .driver         = {
 384                 .name = KBUILD_MODNAME,
 385                 .acpi_match_table = ACPI_PTR(soc_button_acpi_match),
 386         },
 387 };
 388 module_platform_driver(soc_button_driver);
 389
 390 MODULE_LICENSE("GPL");