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 bool active_low; 27 }; 28 29 struct soc_device_data { 30 const struct soc_button_info *button_info; 31 int (*check)(struct device *dev); 32 }; 33 34 /* 35 * Some of the buttons like volume up/down are auto repeat, while others 36 * are not. To support both, we register two platform devices, and put 37 * buttons into them based on whether the key should be auto repeat. 38 */ 39 #define BUTTON_TYPES 2 40 41 struct soc_button_data { 42 struct platform_device *children[BUTTON_TYPES]; 43 }; 44 45 /* 46 * Get the Nth GPIO number from the ACPI object. 47 */ 48 static int soc_button_lookup_gpio(struct device *dev, int acpi_index) 49 { 50 struct gpio_desc *desc; 51 int gpio; 52 53 desc = gpiod_get_index(dev, NULL, acpi_index, GPIOD_ASIS); 54 if (IS_ERR(desc)) 55 return PTR_ERR(desc); 56 57 gpio = desc_to_gpio(desc); 58 59 gpiod_put(desc); 60 61 return gpio; 62 } 63 64 static struct platform_device * 65 soc_button_device_create(struct platform_device *pdev, 66 const struct soc_button_info *button_info, 67 bool autorepeat) 68 { 69 const struct soc_button_info *info; 70 struct platform_device *pd; 71 struct gpio_keys_button *gpio_keys; 72 struct gpio_keys_platform_data *gpio_keys_pdata; 73 int n_buttons = 0; 74 int gpio; 75 int error; 76 77 for (info = button_info; info->name; info++) 78 if (info->autorepeat == autorepeat) 79 n_buttons++; 80 81 gpio_keys_pdata = devm_kzalloc(&pdev->dev, 82 sizeof(*gpio_keys_pdata) + 83 sizeof(*gpio_keys) * n_buttons, 84 GFP_KERNEL); 85 if (!gpio_keys_pdata) 86 return ERR_PTR(-ENOMEM); 87 88 gpio_keys = (void *)(gpio_keys_pdata + 1); 89 n_buttons = 0; 90 91 for (info = button_info; info->name; info++) { 92 if (info->autorepeat != autorepeat) 93 continue; 94 95 gpio = soc_button_lookup_gpio(&pdev->dev, info->acpi_index); 96 if (!gpio_is_valid(gpio)) { 97 /* 98 * Skip GPIO if not present. Note we deliberately 99 * ignore -EPROBE_DEFER errors here. On some devices 100 * Intel is using so called virtual GPIOs which are not 101 * GPIOs at all but some way for AML code to check some 102 * random status bits without need a custom opregion. 103 * In some cases the resources table we parse points to 104 * such a virtual GPIO, since these are not real GPIOs 105 * we do not have a driver for these so they will never 106 * show up, therefore we ignore -EPROBE_DEFER. 107 */ 108 continue; 109 } 110 111 gpio_keys[n_buttons].type = info->event_type; 112 gpio_keys[n_buttons].code = info->event_code; 113 gpio_keys[n_buttons].gpio = gpio; 114 gpio_keys[n_buttons].active_low = info->active_low; 115 gpio_keys[n_buttons].desc = info->name; 116 gpio_keys[n_buttons].wakeup = info->wakeup; 117 /* These devices often use cheap buttons, use 50 ms debounce */ 118 gpio_keys[n_buttons].debounce_interval = 50; 119 n_buttons++; 120 } 121 122 if (n_buttons == 0) { 123 error = -ENODEV; 124 goto err_free_mem; 125 } 126 127 gpio_keys_pdata->buttons = gpio_keys; 128 gpio_keys_pdata->nbuttons = n_buttons; 129 gpio_keys_pdata->rep = autorepeat; 130 131 pd = platform_device_register_resndata(&pdev->dev, "gpio-keys", 132 PLATFORM_DEVID_AUTO, NULL, 0, 133 gpio_keys_pdata, 134 sizeof(*gpio_keys_pdata)); 135 error = PTR_ERR_OR_ZERO(pd); 136 if (error) { 137 dev_err(&pdev->dev, 138 "failed registering gpio-keys: %d\n", error); 139 goto err_free_mem; 140 } 141 142 return pd; 143 144 err_free_mem: 145 devm_kfree(&pdev->dev, gpio_keys_pdata); 146 return ERR_PTR(error); 147 } 148 149 static int soc_button_get_acpi_object_int(const union acpi_object *obj) 150 { 151 if (obj->type != ACPI_TYPE_INTEGER) 152 return -1; 153 154 return obj->integer.value; 155 } 156 157 /* Parse a single ACPI0011 _DSD button descriptor */ 158 static int soc_button_parse_btn_desc(struct device *dev, 159 const union acpi_object *desc, 160 int collection_uid, 161 struct soc_button_info *info) 162 { 163 int upage, usage; 164 165 if (desc->type != ACPI_TYPE_PACKAGE || 166 desc->package.count != 5 || 167 /* First byte should be 1 (control) */ 168 soc_button_get_acpi_object_int(&desc->package.elements[0]) != 1 || 169 /* Third byte should be collection uid */ 170 soc_button_get_acpi_object_int(&desc->package.elements[2]) != 171 collection_uid) { 172 dev_err(dev, "Invalid ACPI Button Descriptor\n"); 173 return -ENODEV; 174 } 175 176 info->event_type = EV_KEY; 177 info->active_low = true; 178 info->acpi_index = 179 soc_button_get_acpi_object_int(&desc->package.elements[1]); 180 upage = soc_button_get_acpi_object_int(&desc->package.elements[3]); 181 usage = soc_button_get_acpi_object_int(&desc->package.elements[4]); 182 183 /* 184 * The UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e descriptors use HID 185 * usage page and usage codes, but otherwise the device is not HID 186 * compliant: it uses one irq per button instead of generating HID 187 * input reports and some buttons should generate wakeups where as 188 * others should not, so we cannot use the HID subsystem. 189 * 190 * Luckily all devices only use a few usage page + usage combinations, 191 * so we can simply check for the known combinations here. 192 */ 193 if (upage == 0x01 && usage == 0x81) { 194 info->name = "power"; 195 info->event_code = KEY_POWER; 196 info->wakeup = true; 197 } else if (upage == 0x01 && usage == 0xca) { 198 info->name = "rotation lock switch"; 199 info->event_type = EV_SW; 200 info->event_code = SW_ROTATE_LOCK; 201 } else if (upage == 0x07 && usage == 0xe3) { 202 info->name = "home"; 203 info->event_code = KEY_LEFTMETA; 204 info->wakeup = true; 205 } else if (upage == 0x0c && usage == 0xe9) { 206 info->name = "volume_up"; 207 info->event_code = KEY_VOLUMEUP; 208 info->autorepeat = true; 209 } else if (upage == 0x0c && usage == 0xea) { 210 info->name = "volume_down"; 211 info->event_code = KEY_VOLUMEDOWN; 212 info->autorepeat = true; 213 } else { 214 dev_warn(dev, "Unknown button index %d upage %02x usage %02x, ignoring\n", 215 info->acpi_index, upage, usage); 216 info->name = "unknown"; 217 info->event_code = KEY_RESERVED; 218 } 219 220 return 0; 221 } 222 223 /* ACPI0011 _DSD btns descriptors UUID: fa6bd625-9ce8-470d-a2c7-b3ca36c4282e */ 224 static const u8 btns_desc_uuid[16] = { 225 0x25, 0xd6, 0x6b, 0xfa, 0xe8, 0x9c, 0x0d, 0x47, 226 0xa2, 0xc7, 0xb3, 0xca, 0x36, 0xc4, 0x28, 0x2e 227 }; 228 229 /* Parse ACPI0011 _DSD button descriptors */ 230 static struct soc_button_info *soc_button_get_button_info(struct device *dev) 231 { 232 struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER }; 233 const union acpi_object *desc, *el0, *uuid, *btns_desc = NULL; 234 struct soc_button_info *button_info; 235 acpi_status status; 236 int i, btn, collection_uid = -1; 237 238 status = acpi_evaluate_object_typed(ACPI_HANDLE(dev), "_DSD", NULL, 239 &buf, ACPI_TYPE_PACKAGE); 240 if (ACPI_FAILURE(status)) { 241 dev_err(dev, "ACPI _DSD object not found\n"); 242 return ERR_PTR(-ENODEV); 243 } 244 245 /* Look for the Button Descriptors UUID */ 246 desc = buf.pointer; 247 for (i = 0; (i + 1) < desc->package.count; i += 2) { 248 uuid = &desc->package.elements[i]; 249 250 if (uuid->type != ACPI_TYPE_BUFFER || 251 uuid->buffer.length != 16 || 252 desc->package.elements[i + 1].type != ACPI_TYPE_PACKAGE) { 253 break; 254 } 255 256 if (memcmp(uuid->buffer.pointer, btns_desc_uuid, 16) == 0) { 257 btns_desc = &desc->package.elements[i + 1]; 258 break; 259 } 260 } 261 262 if (!btns_desc) { 263 dev_err(dev, "ACPI Button Descriptors not found\n"); 264 button_info = ERR_PTR(-ENODEV); 265 goto out; 266 } 267 268 /* The first package describes the collection */ 269 el0 = &btns_desc->package.elements[0]; 270 if (el0->type == ACPI_TYPE_PACKAGE && 271 el0->package.count == 5 && 272 /* First byte should be 0 (collection) */ 273 soc_button_get_acpi_object_int(&el0->package.elements[0]) == 0 && 274 /* Third byte should be 0 (top level collection) */ 275 soc_button_get_acpi_object_int(&el0->package.elements[2]) == 0) { 276 collection_uid = soc_button_get_acpi_object_int( 277 &el0->package.elements[1]); 278 } 279 if (collection_uid == -1) { 280 dev_err(dev, "Invalid Button Collection Descriptor\n"); 281 button_info = ERR_PTR(-ENODEV); 282 goto out; 283 } 284 285 /* There are package.count - 1 buttons + 1 terminating empty entry */ 286 button_info = devm_kcalloc(dev, btns_desc->package.count, 287 sizeof(*button_info), GFP_KERNEL); 288 if (!button_info) { 289 button_info = ERR_PTR(-ENOMEM); 290 goto out; 291 } 292 293 /* Parse the button descriptors */ 294 for (i = 1, btn = 0; i < btns_desc->package.count; i++, btn++) { 295 if (soc_button_parse_btn_desc(dev, 296 &btns_desc->package.elements[i], 297 collection_uid, 298 &button_info[btn])) { 299 button_info = ERR_PTR(-ENODEV); 300 goto out; 301 } 302 } 303 304 out: 305 kfree(buf.pointer); 306 return button_info; 307 } 308 309 static int soc_button_remove(struct platform_device *pdev) 310 { 311 struct soc_button_data *priv = platform_get_drvdata(pdev); 312 313 int i; 314 315 for (i = 0; i < BUTTON_TYPES; i++) 316 if (priv->children[i]) 317 platform_device_unregister(priv->children[i]); 318 319 return 0; 320 } 321 322 static int soc_button_probe(struct platform_device *pdev) 323 { 324 struct device *dev = &pdev->dev; 325 const struct soc_device_data *device_data; 326 const struct soc_button_info *button_info; 327 struct soc_button_data *priv; 328 struct platform_device *pd; 329 int i; 330 int error; 331 332 device_data = acpi_device_get_match_data(dev); 333 if (device_data && device_data->check) { 334 error = device_data->check(dev); 335 if (error) 336 return error; 337 } 338 339 if (device_data && device_data->button_info) { 340 button_info = device_data->button_info; 341 } else { 342 button_info = soc_button_get_button_info(dev); 343 if (IS_ERR(button_info)) 344 return PTR_ERR(button_info); 345 } 346 347 error = gpiod_count(dev, NULL); 348 if (error < 0) { 349 dev_dbg(dev, "no GPIO attached, ignoring...\n"); 350 return -ENODEV; 351 } 352 353 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); 354 if (!priv) 355 return -ENOMEM; 356 357 platform_set_drvdata(pdev, priv); 358 359 for (i = 0; i < BUTTON_TYPES; i++) { 360 pd = soc_button_device_create(pdev, button_info, i == 0); 361 if (IS_ERR(pd)) { 362 error = PTR_ERR(pd); 363 if (error != -ENODEV) { 364 soc_button_remove(pdev); 365 return error; 366 } 367 continue; 368 } 369 370 priv->children[i] = pd; 371 } 372 373 if (!priv->children[0] && !priv->children[1]) 374 return -ENODEV; 375 376 if (!device_data || !device_data->button_info) 377 devm_kfree(dev, button_info); 378 379 return 0; 380 } 381 382 /* 383 * Definition of buttons on the tablet. The ACPI index of each button 384 * is defined in section 2.8.7.2 of "Windows ACPI Design Guide for SoC 385 * Platforms" 386 */ 387 static const struct soc_button_info soc_button_PNP0C40[] = { 388 { "power", 0, EV_KEY, KEY_POWER, false, true, true }, 389 { "home", 1, EV_KEY, KEY_LEFTMETA, false, true, true }, 390 { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false, true }, 391 { "volume_down", 3, EV_KEY, KEY_VOLUMEDOWN, true, false, true }, 392 { "rotation_lock", 4, EV_KEY, KEY_ROTATE_LOCK_TOGGLE, false, false, true }, 393 { } 394 }; 395 396 static const struct soc_device_data soc_device_PNP0C40 = { 397 .button_info = soc_button_PNP0C40, 398 }; 399 400 static const struct soc_button_info soc_button_INT33D3[] = { 401 { "tablet_mode", 0, EV_SW, SW_TABLET_MODE, false, false, false }, 402 { } 403 }; 404 405 static const struct soc_device_data soc_device_INT33D3 = { 406 .button_info = soc_button_INT33D3, 407 }; 408 409 /* 410 * Special device check for Surface Book 2 and Surface Pro (2017). 411 * Both, the Surface Pro 4 (surfacepro3_button.c) and the above mentioned 412 * devices use MSHW0040 for power and volume buttons, however the way they 413 * have to be addressed differs. Make sure that we only load this drivers 414 * for the correct devices by checking the OEM Platform Revision provided by 415 * the _DSM method. 416 */ 417 #define MSHW0040_DSM_REVISION 0x01 418 #define MSHW0040_DSM_GET_OMPR 0x02 // get OEM Platform Revision 419 static const guid_t MSHW0040_DSM_UUID = 420 GUID_INIT(0x6fd05c69, 0xcde3, 0x49f4, 0x95, 0xed, 0xab, 0x16, 0x65, 421 0x49, 0x80, 0x35); 422 423 static int soc_device_check_MSHW0040(struct device *dev) 424 { 425 acpi_handle handle = ACPI_HANDLE(dev); 426 union acpi_object *result; 427 u64 oem_platform_rev = 0; // valid revisions are nonzero 428 429 // get OEM platform revision 430 result = acpi_evaluate_dsm_typed(handle, &MSHW0040_DSM_UUID, 431 MSHW0040_DSM_REVISION, 432 MSHW0040_DSM_GET_OMPR, NULL, 433 ACPI_TYPE_INTEGER); 434 435 if (result) { 436 oem_platform_rev = result->integer.value; 437 ACPI_FREE(result); 438 } 439 440 /* 441 * If the revision is zero here, the _DSM evaluation has failed. This 442 * indicates that we have a Pro 4 or Book 1 and this driver should not 443 * be used. 444 */ 445 if (oem_platform_rev == 0) 446 return -ENODEV; 447 448 dev_dbg(dev, "OEM Platform Revision %llu\n", oem_platform_rev); 449 450 return 0; 451 } 452 453 /* 454 * Button infos for Microsoft Surface Book 2 and Surface Pro (2017). 455 * Obtained from DSDT/testing. 456 */ 457 static const struct soc_button_info soc_button_MSHW0040[] = { 458 { "power", 0, EV_KEY, KEY_POWER, false, true, true }, 459 { "volume_up", 2, EV_KEY, KEY_VOLUMEUP, true, false, true }, 460 { "volume_down", 4, EV_KEY, KEY_VOLUMEDOWN, true, false, true }, 461 { } 462 }; 463 464 static const struct soc_device_data soc_device_MSHW0040 = { 465 .button_info = soc_button_MSHW0040, 466 .check = soc_device_check_MSHW0040, 467 }; 468 469 static const struct acpi_device_id soc_button_acpi_match[] = { 470 { "PNP0C40", (unsigned long)&soc_device_PNP0C40 }, 471 { "INT33D3", (unsigned long)&soc_device_INT33D3 }, 472 { "ID9001", (unsigned long)&soc_device_INT33D3 }, 473 { "ACPI0011", 0 }, 474 475 /* Microsoft Surface Devices (5th and 6th generation) */ 476 { "MSHW0040", (unsigned long)&soc_device_MSHW0040 }, 477 478 { } 479 }; 480 481 MODULE_DEVICE_TABLE(acpi, soc_button_acpi_match); 482 483 static struct platform_driver soc_button_driver = { 484 .probe = soc_button_probe, 485 .remove = soc_button_remove, 486 .driver = { 487 .name = KBUILD_MODNAME, 488 .acpi_match_table = ACPI_PTR(soc_button_acpi_match), 489 }, 490 }; 491 module_platform_driver(soc_button_driver); 492 493 MODULE_LICENSE("GPL"); 494