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