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/leds.h>
  19 #include <linux/mfd/cros_ec.h>
  20 #include <linux/mfd/cros_ec_commands.h>
  21 #include <linux/module.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/pm_wakeup.h>
  24 #include <asm/unaligned.h>
  25
  26 #include "hid-ids.h"
  27
  28 /*
  29  * C(hrome)B(ase)A(ttached)S(witch) - switch exported by Chrome EC and reporting
  30  * state of the "Whiskers" base - attached or detached. Whiskers USB device also
  31  * reports position of the keyboard - folded or not. Combining base state and
  32  * position allows us to generate proper "Tablet mode" events.
  33  */
  34 struct cbas_ec {
  35         struct device *dev;     /* The platform device (EC) */
  36         struct input_dev *input;
  37         bool base_present;
  38         struct notifier_block notifier;
  39 };
  40
  41 static struct cbas_ec cbas_ec;
  42 static DEFINE_SPINLOCK(cbas_ec_lock);
  43 static DEFINE_MUTEX(cbas_ec_reglock);
  44
  45 static bool cbas_parse_base_state(const void *data)
  46 {
  47         u32 switches = get_unaligned_le32(data);
  48
  49         return !!(switches & BIT(EC_MKBP_BASE_ATTACHED));
  50 }
  51
  52 static int cbas_ec_query_base(struct cros_ec_device *ec_dev, bool get_state,
  53                                   bool *state)
  54 {
  55         struct ec_params_mkbp_info *params;
  56         struct cros_ec_command *msg;
  57         int ret;
  58
  59         msg = kzalloc(sizeof(*msg) + max(sizeof(u32), sizeof(*params)),
  60                       GFP_KERNEL);
  61         if (!msg)
  62                 return -ENOMEM;
  63
  64         msg->command = EC_CMD_MKBP_INFO;
  65         msg->version = 1;
  66         msg->outsize = sizeof(*params);
  67         msg->insize = sizeof(u32);
  68         params = (struct ec_params_mkbp_info *)msg->data;
  69         params->info_type = get_state ?
  70                 EC_MKBP_INFO_CURRENT : EC_MKBP_INFO_SUPPORTED;
  71         params->event_type = EC_MKBP_EVENT_SWITCH;
  72
  73         ret = cros_ec_cmd_xfer_status(ec_dev, msg);
  74         if (ret >= 0) {
  75                 if (ret != sizeof(u32)) {
  76                         dev_warn(ec_dev->dev, "wrong result size: %d != %zu\n",
  77                                  ret, sizeof(u32));
  78                         ret = -EPROTO;
  79                 } else {
  80                         *state = cbas_parse_base_state(msg->data);
  81                         ret = 0;
  82                 }
  83         }
  84
  85         kfree(msg);
  86
  87         return ret;
  88 }
  89
  90 static int cbas_ec_notify(struct notifier_block *nb,
  91                               unsigned long queued_during_suspend,
  92                               void *_notify)
  93 {
  94         struct cros_ec_device *ec = _notify;
  95         unsigned long flags;
  96         bool base_present;
  97
  98         if (ec->event_data.event_type == EC_MKBP_EVENT_SWITCH) {
  99                 base_present = cbas_parse_base_state(
 100                                         &ec->event_data.data.switches);
 101                 dev_dbg(cbas_ec.dev,
 102                         "%s: base: %d\n", __func__, base_present);
 103
 104                 if (device_may_wakeup(cbas_ec.dev) ||
 105                     !queued_during_suspend) {
 106
 107                         pm_wakeup_event(cbas_ec.dev, 0);
 108
 109                         spin_lock_irqsave(&cbas_ec_lock, flags);
 110
 111                         /*
 112                          * While input layer dedupes the events, we do not want
 113                          * to disrupt the state reported by the base by
 114                          * overriding it with state reported by the LID. Only
 115                          * report changes, as we assume that on attach the base
 116                          * is not folded.
 117                          */
 118                         if (base_present != cbas_ec.base_present) {
 119                                 input_report_switch(cbas_ec.input,
 120                                                     SW_TABLET_MODE,
 121                                                     !base_present);
 122                                 input_sync(cbas_ec.input);
 123                                 cbas_ec.base_present = base_present;
 124                         }
 125
 126                         spin_unlock_irqrestore(&cbas_ec_lock, flags);
 127                 }
 128         }
 129
 130         return NOTIFY_OK;
 131 }
 132
 133 static __maybe_unused int cbas_ec_resume(struct device *dev)
 134 {
 135         struct cros_ec_device *ec = dev_get_drvdata(dev->parent);
 136         bool base_present;
 137         int error;
 138
 139         error = cbas_ec_query_base(ec, true, &base_present);
 140         if (error) {
 141                 dev_warn(dev, "failed to fetch base state on resume: %d\n",
 142                          error);
 143         } else {
 144                 spin_lock_irq(&cbas_ec_lock);
 145
 146                 cbas_ec.base_present = base_present;
 147
 148                 /*
 149                  * Only report if base is disconnected. If base is connected,
 150                  * it will resend its state on resume, and we'll update it
 151                  * in hammer_event().
 152                  */
 153                 if (!cbas_ec.base_present) {
 154                         input_report_switch(cbas_ec.input, SW_TABLET_MODE, 1);
 155                         input_sync(cbas_ec.input);
 156                 }
 157
 158                 spin_unlock_irq(&cbas_ec_lock);
 159         }
 160
 161         return 0;
 162 }
 163
 164 static SIMPLE_DEV_PM_OPS(cbas_ec_pm_ops, NULL, cbas_ec_resume);
 165
 166 static void cbas_ec_set_input(struct input_dev *input)
 167 {
 168         /* Take the lock so hammer_event() does not race with us here */
 169         spin_lock_irq(&cbas_ec_lock);
 170         cbas_ec.input = input;
 171         spin_unlock_irq(&cbas_ec_lock);
 172 }
 173
 174 static int __cbas_ec_probe(struct platform_device *pdev)
 175 {
 176         struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
 177         struct input_dev *input;
 178         bool base_supported;
 179         int error;
 180
 181         error = cbas_ec_query_base(ec, false, &base_supported);
 182         if (error)
 183                 return error;
 184
 185         if (!base_supported)
 186                 return -ENXIO;
 187
 188         input = devm_input_allocate_device(&pdev->dev);
 189         if (!input)
 190                 return -ENOMEM;
 191
 192         input->name = "Whiskers Tablet Mode Switch";
 193         input->id.bustype = BUS_HOST;
 194
 195         input_set_capability(input, EV_SW, SW_TABLET_MODE);
 196
 197         error = input_register_device(input);
 198         if (error) {
 199                 dev_err(&pdev->dev, "cannot register input device: %d\n",
 200                         error);
 201                 return error;
 202         }
 203
 204         /* Seed the state */
 205         error = cbas_ec_query_base(ec, true, &cbas_ec.base_present);
 206         if (error) {
 207                 dev_err(&pdev->dev, "cannot query base state: %d\n", error);
 208                 return error;
 209         }
 210
 211         input_report_switch(input, SW_TABLET_MODE, !cbas_ec.base_present);
 212
 213         cbas_ec_set_input(input);
 214
 215         cbas_ec.dev = &pdev->dev;
 216         cbas_ec.notifier.notifier_call = cbas_ec_notify;
 217         error = blocking_notifier_chain_register(&ec->event_notifier,
 218                                                  &cbas_ec.notifier);
 219         if (error) {
 220                 dev_err(&pdev->dev, "cannot register notifier: %d\n", error);
 221                 cbas_ec_set_input(NULL);
 222                 return error;
 223         }
 224
 225         device_init_wakeup(&pdev->dev, true);
 226         return 0;
 227 }
 228
 229 static int cbas_ec_probe(struct platform_device *pdev)
 230 {
 231         int retval;
 232
 233         mutex_lock(&cbas_ec_reglock);
 234
 235         if (cbas_ec.input) {
 236                 retval = -EBUSY;
 237                 goto out;
 238         }
 239
 240         retval = __cbas_ec_probe(pdev);
 241
 242 out:
 243         mutex_unlock(&cbas_ec_reglock);
 244         return retval;
 245 }
 246
 247 static int cbas_ec_remove(struct platform_device *pdev)
 248 {
 249         struct cros_ec_device *ec = dev_get_drvdata(pdev->dev.parent);
 250
 251         mutex_lock(&cbas_ec_reglock);
 252
 253         blocking_notifier_chain_unregister(&ec->event_notifier,
 254                                            &cbas_ec.notifier);
 255         cbas_ec_set_input(NULL);
 256
 257         mutex_unlock(&cbas_ec_reglock);
 258         return 0;
 259 }
 260
 261 static const struct acpi_device_id cbas_ec_acpi_ids[] = {
 262         { "GOOG000B", 0 },
 263         { }
 264 };
 265 MODULE_DEVICE_TABLE(acpi, cbas_ec_acpi_ids);
 266
 267 static struct platform_driver cbas_ec_driver = {
 268         .probe = cbas_ec_probe,
 269         .remove = cbas_ec_remove,
 270         .driver = {
 271                 .name = "cbas_ec",
 272                 .acpi_match_table = ACPI_PTR(cbas_ec_acpi_ids),
 273                 .pm = &cbas_ec_pm_ops,
 274         },
 275 };
 276
 277 #define MAX_BRIGHTNESS 100
 278
 279 struct hammer_kbd_leds {
 280         struct led_classdev cdev;
 281         struct hid_device *hdev;
 282         u8 buf[2] ____cacheline_aligned;
 283 };
 284
 285 static int hammer_kbd_brightness_set_blocking(struct led_classdev *cdev,
 286                 enum led_brightness br)
 287 {
 288         struct hammer_kbd_leds *led = container_of(cdev,
 289                                                    struct hammer_kbd_leds,
 290                                                    cdev);
 291         int ret;
 292
 293         led->buf[0] = 0;
 294         led->buf[1] = br;
 295
 296         /*
 297          * Request USB HID device to be in Full On mode, so that sending
 298          * hardware output report and hardware raw request won't fail.
 299          */
 300         ret = hid_hw_power(led->hdev, PM_HINT_FULLON);
 301         if (ret < 0) {
 302                 hid_err(led->hdev, "failed: device not resumed %d\n", ret);
 303                 return ret;
 304         }
 305
 306         ret = hid_hw_output_report(led->hdev, led->buf, sizeof(led->buf));
 307         if (ret == -ENOSYS)
 308                 ret = hid_hw_raw_request(led->hdev, 0, led->buf,
 309                                          sizeof(led->buf),
 310                                          HID_OUTPUT_REPORT,
 311                                          HID_REQ_SET_REPORT);
 312         if (ret < 0)
 313                 hid_err(led->hdev, "failed to set keyboard backlight: %d\n",
 314                         ret);
 315
 316         /* Request USB HID device back to Normal Mode. */
 317         hid_hw_power(led->hdev, PM_HINT_NORMAL);
 318
 319         return ret;
 320 }
 321
 322 static int hammer_register_leds(struct hid_device *hdev)
 323 {
 324         struct hammer_kbd_leds *kbd_backlight;
 325
 326         kbd_backlight = devm_kzalloc(&hdev->dev,
 327                                      sizeof(*kbd_backlight),
 328                                      GFP_KERNEL);
 329         if (!kbd_backlight)
 330                 return -ENOMEM;
 331
 332         kbd_backlight->hdev = hdev;
 333         kbd_backlight->cdev.name = "hammer::kbd_backlight";
 334         kbd_backlight->cdev.max_brightness = MAX_BRIGHTNESS;
 335         kbd_backlight->cdev.brightness_set_blocking =
 336                 hammer_kbd_brightness_set_blocking;
 337         kbd_backlight->cdev.flags = LED_HW_PLUGGABLE;
 338
 339         /* Set backlight to 0% initially. */
 340         hammer_kbd_brightness_set_blocking(&kbd_backlight->cdev, 0);
 341
 342         return devm_led_classdev_register(&hdev->dev, &kbd_backlight->cdev);
 343 }
 344
 345 #define HID_UP_GOOGLEVENDOR     0xffd10000
 346 #define HID_VD_KBD_FOLDED       0x00000019
 347 #define WHISKERS_KBD_FOLDED     (HID_UP_GOOGLEVENDOR | HID_VD_KBD_FOLDED)
 348
 349 /* HID usage for keyboard backlight (Alphanumeric display brightness) */
 350 #define HID_AD_BRIGHTNESS       0x00140046
 351
 352 static int hammer_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 353                                 struct hid_field *field,
 354                                 struct hid_usage *usage,
 355                                 unsigned long **bit, int *max)
 356 {
 357         if (hdev->product == USB_DEVICE_ID_GOOGLE_WHISKERS &&
 358             usage->hid == WHISKERS_KBD_FOLDED) {
 359                 /*
 360                  * We do not want to have this usage mapped as it will get
 361                  * mixed in with "base attached" signal and delivered over
 362                  * separate input device for tablet switch mode.
 363                  */
 364                 return -1;
 365         }
 366
 367         return 0;
 368 }
 369
 370 static int hammer_event(struct hid_device *hid, struct hid_field *field,
 371                         struct hid_usage *usage, __s32 value)
 372 {
 373         unsigned long flags;
 374
 375         if (hid->product == USB_DEVICE_ID_GOOGLE_WHISKERS &&
 376             usage->hid == WHISKERS_KBD_FOLDED) {
 377                 spin_lock_irqsave(&cbas_ec_lock, flags);
 378
 379                 hid_dbg(hid, "%s: base: %d, folded: %d\n", __func__,
 380                         cbas_ec.base_present, value);
 381
 382                 /*
 383                  * We should not get event if base is detached, but in case
 384                  * we happen to service HID and EC notifications out of order
 385                  * let's still check the "base present" flag.
 386                  */
 387                 if (cbas_ec.input && cbas_ec.base_present) {
 388                         input_report_switch(cbas_ec.input,
 389                                             SW_TABLET_MODE, value);
 390                         input_sync(cbas_ec.input);
 391                 }
 392
 393                 spin_unlock_irqrestore(&cbas_ec_lock, flags);
 394                 return 1; /* We handled this event */
 395         }
 396
 397         return 0;
 398 }
 399
 400 static bool hammer_is_keyboard_interface(struct hid_device *hdev)
 401 {
 402         struct hid_report_enum *re = &hdev->report_enum[HID_INPUT_REPORT];
 403         struct hid_report *report;
 404
 405         list_for_each_entry(report, &re->report_list, list)
 406                 if (report->application == HID_GD_KEYBOARD)
 407                         return true;
 408
 409         return false;
 410 }
 411
 412 static bool hammer_has_backlight_control(struct hid_device *hdev)
 413 {
 414         struct hid_report_enum *re = &hdev->report_enum[HID_OUTPUT_REPORT];
 415         struct hid_report *report;
 416         int i, j;
 417
 418         list_for_each_entry(report, &re->report_list, list) {
 419                 if (report->application != HID_GD_KEYBOARD)
 420                         continue;
 421
 422                 for (i = 0; i < report->maxfield; i++) {
 423                         struct hid_field *field = report->field[i];
 424
 425                         for (j = 0; j < field->maxusage; j++)
 426                                 if (field->usage[j].hid == HID_AD_BRIGHTNESS)
 427                                         return true;
 428                 }
 429         }
 430
 431         return false;
 432 }
 433
 434 static int hammer_probe(struct hid_device *hdev,
 435                         const struct hid_device_id *id)
 436 {
 437         int error;
 438
 439         /*
 440          * We always want to poll for, and handle tablet mode events from
 441          * Whiskers, even when nobody has opened the input device. This also
 442          * prevents the hid core from dropping early tablet mode events from
 443          * the device.
 444          */
 445         if (hdev->product == USB_DEVICE_ID_GOOGLE_WHISKERS &&
 446                         hammer_is_keyboard_interface(hdev))
 447                 hdev->quirks |= HID_QUIRK_ALWAYS_POLL;
 448
 449         error = hid_parse(hdev);
 450         if (error)
 451                 return error;
 452
 453         error = hid_hw_start(hdev, HID_CONNECT_DEFAULT);
 454         if (error)
 455                 return error;
 456
 457         if (hammer_has_backlight_control(hdev)) {
 458                 error = hammer_register_leds(hdev);
 459                 if (error)
 460                         hid_warn(hdev,
 461                                 "Failed to register keyboard backlight: %d\n",
 462                                 error);
 463         }
 464
 465         return 0;
 466 }
 467
 468
 469 static const struct hid_device_id hammer_devices[] = {
 470         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 471                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_HAMMER) },
 472         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 473                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_STAFF) },
 474         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 475                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WAND) },
 476         { HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
 477                      USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_WHISKERS) },
 478         { }
 479 };
 480 MODULE_DEVICE_TABLE(hid, hammer_devices);
 481
 482 static struct hid_driver hammer_driver = {
 483         .name = "hammer",
 484         .id_table = hammer_devices,
 485         .probe = hammer_probe,
 486         .input_mapping = hammer_input_mapping,
 487         .event = hammer_event,
 488 };
 489
 490 static int __init hammer_init(void)
 491 {
 492         int error;
 493
 494         error = platform_driver_register(&cbas_ec_driver);
 495         if (error)
 496                 return error;
 497
 498         error = hid_register_driver(&hammer_driver);
 499         if (error) {
 500                 platform_driver_unregister(&cbas_ec_driver);
 501                 return error;
 502         }
 503
 504         return 0;
 505 }
 506 module_init(hammer_init);
 507
 508 static void __exit hammer_exit(void)
 509 {
 510         hid_unregister_driver(&hammer_driver);
 511         platform_driver_unregister(&cbas_ec_driver);
 512 }
 513 module_exit(hammer_exit);
 514
 515 MODULE_LICENSE("GPL");