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"); 481