drivers/hid/hid-google-hammer.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  *  HID driver for Google Hammer device.
   4  *
   5  *  Copyright (c) 2017 Google Inc.
   6  *  Author: Wei-Ning Huang <wnhuang@google.com>
   7  */
   8
   9 /*
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License as published by the Free
  12  * Software Foundation; either version 2 of the License, or (at your option)
  13  * any later version.
  14  */
  15
  16 #include <linux/acpi.h>
  17 #include <linux/hid.h>
  18 #include <linux/input/vivaldi-fmap.h>
  19 #include <linux/leds.h>
  20 #include <linux/module.h>
  21 #include <linux/of.h>
  22 #include <linux/platform_data/cros_ec_commands.h>
  23 #include <linux/platform_data/cros_ec_proto.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/pm_wakeup.h>
  26 #include <asm/unaligned.h>
  27
  28 #include "hid-ids.h"
  29 #include "hid-vivaldi-common.h"
  30
  31 /*
  32  * C(hrome)B(ase)A(ttached)S(witch) - switch exported by Chrome EC and reporting
  33  * state of the "Whiskers" base - attached or detached. Whiskers USB device also
  34  * reports position of the keyboard - folded or not. Combining base state and
  35  * position allows us to generate proper "Tablet mode" events.
  36  */
  37 struct cbas_ec {
  38         struct device *dev;     /* The platform device (EC) */
  39         struct input_dev *input;
  40         bool base_present;
  41         bool base_folded;
  42         struct notifier_block notifier;
  43 };
  44
  45 static struct cbas_ec cbas_ec;
  46 static DEFINE_SPINLOCK(cbas_ec_lock);
  47 static DEFINE_MUTEX(cbas_ec_reglock);
  48
  49 static bool cbas_parse_base_state(const void *data)
  50 {
  51         u32 switches = get_unaligned_le32(data);
  52
  53         return !!(switches & BIT(EC_MKBP_BASE_ATTACHED));
  54 }
  55
  56 static int cbas_ec_query_base(struct cros_ec_device *ec_dev, bool get_state,
  57                                   bool *state)
  58 {
  59         struct ec_params_mkbp_info *params;
  60         struct cros_ec_command *msg;
  61         int ret;
  62
  63         msg = kzalloc(struct_size(msg, data, max(sizeof(u32), sizeof(*params))),
  64                       GFP_KERNEL);
  65         if (!msg)
  66                 return -ENOMEM;
  67
  68         msg->command = EC_CMD_MKBP_INFO;
  69         msg->version = 1;
  70         msg->outsize = sizeof(*params);
  71         msg->insize = sizeof(u32);
  72         params = (struct ec_params_mkbp_info *)msg->data;
  73         params->info_type = get_state ?
  74                 EC_MKBP_INFO_CURRENT : EC_MKBP_INFO_SUPPORTED;
  75         params->event_type = EC_MKBP_EVENT_SWITCH;
  76
  77         ret = cros_ec_cmd_xfer_status(ec_dev, msg);
  78         if (ret >= 0) {
  79                 if (ret != sizeof(u32)) {
  80                         dev_warn(ec_dev->dev, "wrong result size: %d != %zu\n",
  81                                  ret, sizeof(u32));
  82                         ret = -EPROTO;
  83                 } else {
  84                         *state = cbas_parse_base_state(msg->data);
  85                         ret = 0;
  86                 }
  87         }
  88
  89         kfree(msg);
  90
  91         return ret;
  92 }
  93
  94 static int cbas_ec_notify(struct notifier_block *nb,
  95                               unsigned long queued_during_suspend,
  96                               void *_notify)
  97 {
  98         struct cros_ec_device *ec = _notify;
  99         unsigned long flags;
 100         bool base_present;
 101
 102         if (ec->event_data.event_type == EC_MKBP_EVENT_SWITCH) {
 103                 base_present = cbas_parse_base_state(
 104                                         &ec->event_data.data.switches);
 105                 dev_dbg(cbas_ec.dev,
 106                         "%s: base: %d\n", __func__, base_present);
 107
 108                 if (device_may_wakeup(cbas_ec.dev) ||
 109                     !queued_during_suspend) {
 110
 111                         pm_wakeup_event(cbas_ec.dev, 0);
 112
 113                         spin_lock_irqsave(&cbas_ec_lock, flags);
 114
 115                         /*
 116                          * While input layer dedupes the events, we do not want
 117                          * to disrupt the state reported by the base by
 118                          * overriding it with state reported by the LID. Only
 119                          * report changes, as we assume that on attach the base
 120                          * is not folded.
 121                          */
 122                         if (base_present != cbas_ec.base_present) {
 123                                 input_report_switch(cbas_ec.input,
 124                                                     SW_TABLET_MODE,
 125                                                     !base_present);
 126                                 input_sync(cbas_ec.input);
 127                                 cbas_ec.base_present = base_present;
 128                         }
 129
 130                         spin_unlock_irqrestore(&cbas_ec_lock, flags);
 131                 }
 132         }
 133
 134         return NOTIFY_OK;
 135 }
 136
 137 static __maybe_unused int cbas_ec_resume(struct device *dev)
 138 {
 139         struct cros_ec_device *ec = dev_get_drvdata(dev->parent);
 140         bool base_present;
 141         int error;
 142
 143         error = cbas_ec_query_base(ec, true, &base_present);
 144         if (error) {
 145                 dev_warn(dev, "failed to fetch base state on resume: %d\n",
 146                          error);
 147         } else {
 148                 spin_lock_irq(&cbas_ec_lock);
 149
 150                 cbas_ec.base_present = base_present;
 151
 152                 /*
 153                  * Only report if base is disconnected. If base is connected,
 154                  * it will resend its state on resume, and we'll update it
 155                  * in hammer_event().
 156                  */
 157                 if (!cbas_ec.base_present) {
 158                         input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
 159                         input_sync(cbas_ec.input);
 160                 }
 161
 162                 spin_unlock_irq(&cbas_ec_lock);
 163         }
 164
 165         return 0;
 166 }
 167
 168 static SIMPLE_DEV_PM_OPS(cbas_ec_pm_ops, NULL, cbas_ec_resume);
 169
 170 static void cbas_ec_set_input(struct input_dev *input)
 171 {
 172         /* Take the lock so hammer_event() does not race with us here */
 173         spin_lock_irq(&cbas_ec_lock);
 174         cbas_ec.input = input;
 175         spin_unlock_irq(&cbas_ec_lock);
 176 }
 177
 178 static int __cbas_ec_probe(struct platform_device *pdev)
 179 {
 180         struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
 181         struct input_dev *input;
 182         bool base_supported;
 183         int error;
 184
 185         error = cbas_ec_query_base(ec, false, &base_supported);
 186         if (error)
 187                 return error;
 188
 189         if (!base_supported)
 190                 return -ENXIO;
 191
 192         input = devm_input_allocate_device(&pdev->dev);
 193         if (!input)
 194                 return -ENOMEM;
 195
 196         input->name = "Whiskers Tablet Mode Switch";
 197         input->id.bustype = BUS_HOST;
 198
 199         input_set_capability(input, EV_SW, SW_TABLET_MODE);
 200
 201         error = input_register_device(input);
 202         if (error) {
 203                 dev_err(&pdev->dev, "cannot register input device: %d\n",
 204                         error);
 205                 return error;
 206         }
 207
 208         /* Seed the state */
 209         error = cbas_ec_query_base(ec, true, &cbas_ec.base_present);
 210         if (error) {
 211                 dev_err(&pdev->dev, "cannot query base state: %d\n", error);
 212                 return error;
 213         }
 214
 215         if (!cbas_ec.base_present)
 216                 cbas_ec.base_folded = false;
 217
 218         dev_dbg(&pdev->dev, "%s: base: %d, folded: %d\n", __func__,
 219                 cbas_ec.base_present, cbas_ec.base_folded);
 220
 221         input_report_switch(input, SW_TABLET_MODE,
 222                             !cbas_ec.base_present || cbas_ec.base_folded);
 223
 224         cbas_ec_set_input(input);
 225
 226         cbas_ec.dev = &pdev->dev;
 227         cbas_ec.notifier.notifier_call = cbas_ec_notify;
 228         error = blocking_notifier_chain_register(&ec->event_notifier,
 229                                                  &cbas_ec.notifier);
 230         if (error) {
 231                 dev_err(&pdev->dev, "cannot register notifier: %d\n", error);
 232                 cbas_ec_set_input(NULL);
 233                 return error;
 234         }
 235
 236         device_init_wakeup(&pdev->dev, true);
 237         return 0;
 238 }
 239
 240 static int cbas_ec_probe(struct platform_device *pdev)
 241 {
 242         int retval;
 243
 244         mutex_lock(&cbas_ec_reglock);
 245
 246         if (cbas_ec.input) {
 247                 retval = -EBUSY;
 248                 goto out;
 249         }
 250
 251         retval = __cbas_ec_probe(pdev);
 252
 253 out:
 254         mutex_unlock(&cbas_ec_reglock);
 255         return retval;
 256 }
 257
 258 static int cbas_ec_remove(struct platform_device *pdev)
 259 {
 260         struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
 261
 262         mutex_lock(&cbas_ec_reglock);
 263
 264         blocking_notifier_chain_unregister(&ec->event_notifier,
 265                                            &cbas_ec.notifier);
 266         cbas_ec_set_input(NULL);
 267
 268         mutex_unlock(&cbas_ec_reglock);
 269         return 0;
 270 }
 271
 272 static const struct acpi_device_id cbas_ec_acpi_ids[] = {
 273         { "GOOG000B", 0 },
 274         { }
 275 };
 276 MODULE_DEVICE_TABLE(acpi, cbas_ec_acpi_ids);
 277
 278 #ifdef CONFIG_OF
 279 static const struct of_device_id cbas_ec_of_match[] = {
 280         { .compatible = "google,cros-cbas" },
 281         { },
 282 };
 283 MODULE_DEVICE_TABLE(of, cbas_ec_of_match);
 284 #endif
 285
 286 static struct platform_driver cbas_ec_driver = {
 287         .probe = cbas_ec_probe,
 288         .remove = cbas_ec_remove,
 289         .driver = {
 290                 .name = "cbas_ec",
 291                 .acpi_match_table = ACPI_PTR(cbas_ec_acpi_ids),
 292                 .of_match_table = of_match_ptr(cbas_ec_of_match),
 293                 .pm = &cbas_ec_pm_ops,
 294         },
 295 };
 296
 297 #define MAX_BRIGHTNESS 100
 298
 299 struct hammer_kbd_leds {
 300         struct led_classdev cdev;
 301         struct hid_device *hdev;
 302         u8 buf[2] ____cacheline_aligned;
 303 };
 304
 305 static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
 306                 enum led_brightness br)
 307 {
 308         struct hammer_kbd_leds *led = container_of(cdev,
 309                                                    struct hammer_kbd_leds,
 310                                                    cdev);
 311         int ret;
 312
 313         led->buf[0] = 0;
 314         led->buf[1] = br;
 315
 316         /*
 317          * Request USB HID device to be in Full On mode, so that sending
 318          * hardware output report and hardware raw request won't fail.
 319          */
 320         ret = hid_hw_power(led->hdev, PM_HINT_FULLON);
 321         if (ret < 0) {
 322                 hid_err(led->hdev, "failed: device not resumed %d\n", ret);
 323                 return ret;
 324         }
 325
 326         ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
 327         if (ret == -ENOSYS)
 328                 ret = hid_hw_raw_request(led->hdev, 0, led->buf,
 329                                          sizeof(led->buf),
 330                                          HID_OUTPUT_REPORT,
 331                                          HID_REQ_SET_REPORT);
 332         if (ret < 0)
 333                 hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
 334                         ret);
 335
 336         /* Request USB HID device back to Normal Mode. */
 337         hid_hw_power(led->hdev, PM_HINT_NORMAL);
 338
 339         return ret;
 340 }
 341
 342 static int hammer_register_leds(struct hid_device *hdev)
 343 {
 344         struct hammer_kbd_leds *kbd_backlight;
 345
 346         kbd_backlight = devm_kzalloc(&hdev->dev, sizeof(*kbd_backlight),
 347                                      GFP_KERNEL);
 348         if (!kbd_backlight)
 349                 return -ENOMEM;
 350
 351         kbd_backlight->hdev = hdev;
 352         kbd_backlight->cdev.name = "hammer::kbd_backlight";
 353         kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
 354         kbd_backlight->cdev.brightness_set_blocking =
 355                 hammer_kbd_brightness_set_blocking;
 356         kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;
 357
 358         /* Set backlight to 0% initially. */
 359         hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
 360
 361         return devm_led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
 362 }
 363
 364 #define HID_UP_GOOGLEVENDOR     0xffd10000
 365 #define HID_VD_KBD_FOLDED       0x00000019
 366 #define HID_USAGE_KBD_FOLDED    (HID_UP_GOOGLEVENDOR | HID_VD_KBD_FOLDED)
 367
 368 /* HID usage for keyboard backlight (Alphanumeric display brightness) */
 369 #define HID_AD_BRIGHTNESS       0x00140046
 370
 371 static int hammer_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 372                                 struct hid_field *field,
 373                                 struct hid_usage *usage,
 374                                 unsigned long **bit, int *max)
 375 {
 376         if (usage->hid == HID_USAGE_KBD_FOLDED) {
 377                 /*
 378                  * We do not want to have this usage mapped as it will get
 379                  * mixed in with "base attached" signal and delivered over
 380                  * separate input device for tablet switch mode.
 381                  */
 382                 return -1;
 383         }
 384
 385         return 0;
 386 }
 387
 388 static void hammer_folded_event(struct hid_device *hdev, bool folded)
 389 {
 390         unsigned long flags;
 391
 392         spin_lock_irqsave(&cbas_ec_lock, flags);
 393
 394         /*
 395          * If we are getting events from Whiskers that means that it
 396          * is attached to the lid.
 397          */
 398         cbas_ec.base_present = true;
 399         cbas_ec.base_folded = folded;
 400         hid_dbg(hdev, "%s: base: %d, folded: %d\n", __func__,
 401                 cbas_ec.base_present, cbas_ec.base_folded);
 402
 403         if (cbas_ec.input) {
 404                 input_report_switch(cbas_ec.input, SW_TABLET_MODE, folded);
 405                 input_sync(cbas_ec.input);
 406         }
 407
 408         spin_unlock_irqrestore(&cbas_ec_lock, flags);
 409 }
 410
 411 static int hammer_event(struct hid_device *hid, struct hid_field *field,
 412                         struct hid_usage *usage, __s32 value)
 413 {
 414         if (usage->hid == HID_USAGE_KBD_FOLDED) {
 415                 hammer_folded_event(hid, value);
 416                 return 1; /* We handled this event */
 417         }
 418
 419         return 0;
 420 }
 421
 422 static bool hammer_has_usage(struct hid_device *hdev, unsigned int report_type,
 423                         unsigned application, unsigned usage)
 424 {
 425         struct hid_report_enum *re = &hdev->report_enum[report_type];
 426         struct hid_report *report;
 427         int i, j;
 428
 429         list_for_each_entry(report, &re->report_list, list) {
 430                 if (report->application != application)
 431                         continue;
 432
 433                 for (i = 0; i < report->maxfield; i++) {
 434                         struct hid_field *field = report->field[i];
 435
 436                         for (j = 0; j < field->maxusage; j++)
 437                                 if (field->usage[j].hid == usage)
 438                                         return true;
 439                 }
 440         }
 441
 442         return false;
 443 }
 444
 445 static bool hammer_has_folded_event(struct hid_device *hdev)
 446 {
 447         return hammer_has_usage(hdev, HID_INPUT_REPORT,
 448                                 HID_GD_KEYBOARD, HID_USAGE_KBD_FOLDED);
 449 }
 450
 451 static bool hammer_has_backlight_control(struct hid_device *hdev)
 452 {
 453         return hammer_has_usage(hdev, HID_OUTPUT_REPORT,
 454                                 HID_GD_KEYBOARD, HID_AD_BRIGHTNESS);
 455 }
 456
 457 static void hammer_get_folded_state(struct hid_device *hdev)
 458 {
 459         struct hid_report *report;
 460         char *buf;
 461         int len, rlen;
 462         int a;
 463
 464         report = hdev->report_enum[HID_INPUT_REPORT].report_id_hash[0x0];
 465
 466         if (!report || report->maxfield < 1)
 467                 return;
 468
 469         len = hid_report_len(report) + 1;
 470
 471         buf = kmalloc(len, GFP_KERNEL);
 472         if (!buf)
 473                 return;
 474
 475         rlen = hid_hw_raw_request(hdev, report->id, buf, len, report->type, HID_REQ_GET_REPORT);
 476
 477         if (rlen != len) {
 478                 hid_warn(hdev, "Unable to read base folded state: %d (expected %d)\n", rlen, len);
 479                 goto out;
 480         }
 481
 482         for (a = 0; a < report->maxfield; a++) {
 483                 struct hid_field *field = report->field[a];
 484
 485                 if (field->usage->hid == HID_USAGE_KBD_FOLDED) {
 486                         u32 value = hid_field_extract(hdev, buf+1,
 487                                         field->report_offset, field->report_size);
 488
 489                         hammer_folded_event(hdev, value);
 490                         break;
 491                 }
 492         }
 493
 494 out:
 495         kfree(buf);
 496 }
 497
 498 static void hammer_stop(void *hdev)
 499 {
 500         hid_hw_stop(hdev);
 501 }
 502
 503 static int hammer_probe(struct hid_device *hdev,
 504                         const struct hid_device_id *id)
 505 {
 506         struct vivaldi_data *vdata;
 507         int error;
 508
 509         vdata = devm_kzalloc(&hdev->dev, sizeof(*vdata), GFP_KERNEL);
 510         if (!vdata)
 511                 return -ENOMEM;
 512
 513         hid_set_drvdata(hdev, vdata);
 514
 515         error = hid_parse(hdev);
 516         if (error)
 517                 return error;
 518
 519         error = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 520         if (error)
 521                 return error;
 522
 523         error = devm_add_action(&hdev->dev, hammer_stop, hdev);
 524         if (error)
 525                 return error;
 526
 527         /*
 528          * We always want to poll for, and handle tablet mode events from
 529          * devices that have folded usage, even when nobody has opened the input
 530          * device. This also prevents the hid core from dropping early tablet
 531          * mode events from the device.
 532          */
 533         if (hammer_has_folded_event(hdev)) {
 534                 hdev->quirks |= HID_QUIRK_ALWAYS_POLL;
 535                 error = hid_hw_open(hdev);
 536                 if (error)
 537                         return error;
 538
 539                 hammer_get_folded_state(hdev);
 540         }
 541
 542         if (hammer_has_backlight_control(hdev)) {
 543                 error = hammer_register_leds(hdev);
 544                 if (error)
 545                         hid_warn(hdev,
 546                                 "Failed to register keyboard backlight: %d\n",
 547                                 error);
 548         }
 549
 550         return 0;
 551 }
 552
 553 static void hammer_remove(struct hid_device *hdev)
 554 {
 555         unsigned long flags;
 556
 557         if (hammer_has_folded_event(hdev)) {
 558                 hid_hw_close(hdev);
 559
 560                 /*
 561                  * If we are disconnecting then most likely Whiskers is
 562                  * being removed. Even if it is not removed, without proper
 563                  * keyboard we should not stay in clamshell mode.
 564                  *
 565                  * The reason for doing it here and not waiting for signal
 566                  * from EC, is that on some devices there are high leakage
 567                  * on Whiskers pins and we do not detect disconnect reliably,
 568                  * resulting in devices being stuck in clamshell mode.
 569                  */
 570                 spin_lock_irqsave(&cbas_ec_lock, flags);
 571                 if (cbas_ec.input && cbas_ec.base_present) {
 572                         input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
 573                         input_sync(cbas_ec.input);
 574                 }
 575                 cbas_ec.base_present = false;
 576                 spin_unlock_irqrestore(&cbas_ec_lock, flags);
 577         }
 578
 579         /* Unregistering LEDs and stopping the hardware is done via devm */
 580 }
 581
 582 static const struct hid_device_id hammer_devices[] = {
 583         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 584                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_DON) },
 585         { HID_DEVICE(BUS_USB, HID_GROUP_VIVALDI,
 586                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_EEL) },
 587         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 588                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
 589         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 590                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MAGNEMITE) },
 591         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 592                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MASTERBALL) },
 593         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 594                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_MOONBALL) },
 595         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 596                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
 597         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 598                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) },
 599         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 600                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WHISKERS) },
 601         { }
 602 };
 603 MODULE_DEVICE_TABLE(hid, hammer_devices);
 604
 605 static struct hid_driver hammer_driver = {
 606         .name = "hammer",
 607         .id_table = hammer_devices,
 608         .probe = hammer_probe,
 609         .remove = hammer_remove,
 610         .feature_mapping = vivaldi_feature_mapping,
 611         .input_configured = vivaldi_input_configured,
 612         .input_mapping = hammer_input_mapping,
 613         .event = hammer_event,
 614 };
 615
 616 static int __init hammer_init(void)
 617 {
 618         int error;
 619
 620         error = platform_driver_register(&cbas_ec_driver);
 621         if (error)
 622                 return error;
 623
 624         error = hid_register_driver(&hammer_driver);
 625         if (error) {
 626                 platform_driver_unregister(&cbas_ec_driver);
 627                 return error;
 628         }
 629
 630         return 0;
 631 }
 632 module_init(hammer_init);
 633
 634 static void __exit hammer_exit(void)
 635 {
 636         hid_unregister_driver(&hammer_driver);
 637         platform_driver_unregister(&cbas_ec_driver);
 638 }
 639 module_exit(hammer_exit);
 640
 641 MODULE_LICENSE("GPL");