drivers/mfd/cros_ec_dev.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * cros_ec_dev - expose the Chrome OS Embedded Controller to user-space
   4  *
   5  * Copyright (C) 2014 Google, Inc.
   6  */
   7
   8 #include <linux/fs.h>
   9 #include <linux/mfd/core.h>
  10 #include <linux/module.h>
  11 #include <linux/mod_devicetable.h>
  12 #include <linux/of_platform.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/pm.h>
  15 #include <linux/slab.h>
  16 #include <linux/uaccess.h>
  17
  18 #include "cros_ec_dev.h"
  19
  20 #define DRV_NAME "cros-ec-dev"
  21
  22 /* Device variables */
  23 #define CROS_MAX_DEV 128
  24 static int ec_major;
  25
  26 static struct class cros_class = {
  27         .owner          = THIS_MODULE,
  28         .name           = "chromeos",
  29 };
  30
  31 /* Basic communication */
  32 static int ec_get_version(struct cros_ec_dev *ec, char *str, int maxlen)
  33 {
  34         struct ec_response_get_version *resp;
  35         static const char * const current_image_name[] = {
  36                 "unknown", "read-only", "read-write", "invalid",
  37         };
  38         struct cros_ec_command *msg;
  39         int ret;
  40
  41         msg = kmalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
  42         if (!msg)
  43                 return -ENOMEM;
  44
  45         msg->version = 0;
  46         msg->command = EC_CMD_GET_VERSION + ec->cmd_offset;
  47         msg->insize = sizeof(*resp);
  48         msg->outsize = 0;
  49
  50         ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
  51         if (ret < 0)
  52                 goto exit;
  53
  54         if (msg->result != EC_RES_SUCCESS) {
  55                 snprintf(str, maxlen,
  56                          "%s\nUnknown EC version: EC returned %d\n",
  57                          CROS_EC_DEV_VERSION, msg->result);
  58                 ret = -EINVAL;
  59                 goto exit;
  60         }
  61
  62         resp = (struct ec_response_get_version *)msg->data;
  63         if (resp->current_image >= ARRAY_SIZE(current_image_name))
  64                 resp->current_image = 3; /* invalid */
  65
  66         snprintf(str, maxlen, "%s\n%s\n%s\n%s\n", CROS_EC_DEV_VERSION,
  67                  resp->version_string_ro, resp->version_string_rw,
  68                  current_image_name[resp->current_image]);
  69
  70         ret = 0;
  71 exit:
  72         kfree(msg);
  73         return ret;
  74 }
  75
  76 static int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
  77 {
  78         struct cros_ec_command *msg;
  79         int ret;
  80
  81         if (ec->features[0] == -1U && ec->features[1] == -1U) {
  82                 /* features bitmap not read yet */
  83
  84                 msg = kmalloc(sizeof(*msg) + sizeof(ec->features), GFP_KERNEL);
  85                 if (!msg)
  86                         return -ENOMEM;
  87
  88                 msg->version = 0;
  89                 msg->command = EC_CMD_GET_FEATURES + ec->cmd_offset;
  90                 msg->insize = sizeof(ec->features);
  91                 msg->outsize = 0;
  92
  93                 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
  94                 if (ret < 0 || msg->result != EC_RES_SUCCESS) {
  95                         dev_warn(ec->dev, "cannot get EC features: %d/%d\n",
  96                                  ret, msg->result);
  97                         memset(ec->features, 0, sizeof(ec->features));
  98                 } else {
  99                         memcpy(ec->features, msg->data, sizeof(ec->features));
 100                 }
 101
 102                 dev_dbg(ec->dev, "EC features %08x %08x\n",
 103                         ec->features[0], ec->features[1]);
 104
 105                 kfree(msg);
 106         }
 107
 108         return ec->features[feature / 32] & EC_FEATURE_MASK_0(feature);
 109 }
 110
 111 /* Device file ops */
 112 static int ec_device_open(struct inode *inode, struct file *filp)
 113 {
 114         struct cros_ec_dev *ec = container_of(inode->i_cdev,
 115                                               struct cros_ec_dev, cdev);
 116         filp->private_data = ec;
 117         nonseekable_open(inode, filp);
 118         return 0;
 119 }
 120
 121 static int ec_device_release(struct inode *inode, struct file *filp)
 122 {
 123         return 0;
 124 }
 125
 126 static ssize_t ec_device_read(struct file *filp, char __user *buffer,
 127                               size_t length, loff_t *offset)
 128 {
 129         struct cros_ec_dev *ec = filp->private_data;
 130         char msg[sizeof(struct ec_response_get_version) +
 131                  sizeof(CROS_EC_DEV_VERSION)];
 132         size_t count;
 133         int ret;
 134
 135         if (*offset != 0)
 136                 return 0;
 137
 138         ret = ec_get_version(ec, msg, sizeof(msg));
 139         if (ret)
 140                 return ret;
 141
 142         count = min(length, strlen(msg));
 143
 144         if (copy_to_user(buffer, msg, count))
 145                 return -EFAULT;
 146
 147         *offset = count;
 148         return count;
 149 }
 150
 151 /* Ioctls */
 152 static long ec_device_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
 153 {
 154         long ret;
 155         struct cros_ec_command u_cmd;
 156         struct cros_ec_command *s_cmd;
 157
 158         if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
 159                 return -EFAULT;
 160
 161         if ((u_cmd.outsize > EC_MAX_MSG_BYTES) ||
 162             (u_cmd.insize > EC_MAX_MSG_BYTES))
 163                 return -EINVAL;
 164
 165         s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
 166                         GFP_KERNEL);
 167         if (!s_cmd)
 168                 return -ENOMEM;
 169
 170         if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) {
 171                 ret = -EFAULT;
 172                 goto exit;
 173         }
 174
 175         if (u_cmd.outsize != s_cmd->outsize ||
 176             u_cmd.insize != s_cmd->insize) {
 177                 ret = -EINVAL;
 178                 goto exit;
 179         }
 180
 181         s_cmd->command += ec->cmd_offset;
 182         ret = cros_ec_cmd_xfer(ec->ec_dev, s_cmd);
 183         /* Only copy data to userland if data was received. */
 184         if (ret < 0)
 185                 goto exit;
 186
 187         if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize))
 188                 ret = -EFAULT;
 189 exit:
 190         kfree(s_cmd);
 191         return ret;
 192 }
 193
 194 static long ec_device_ioctl_readmem(struct cros_ec_dev *ec, void __user *arg)
 195 {
 196         struct cros_ec_device *ec_dev = ec->ec_dev;
 197         struct cros_ec_readmem s_mem = { };
 198         long num;
 199
 200         /* Not every platform supports direct reads */
 201         if (!ec_dev->cmd_readmem)
 202                 return -ENOTTY;
 203
 204         if (copy_from_user(&s_mem, arg, sizeof(s_mem)))
 205                 return -EFAULT;
 206
 207         num = ec_dev->cmd_readmem(ec_dev, s_mem.offset, s_mem.bytes,
 208                                   s_mem.buffer);
 209         if (num <= 0)
 210                 return num;
 211
 212         if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem)))
 213                 return -EFAULT;
 214
 215         return num;
 216 }
 217
 218 static long ec_device_ioctl(struct file *filp, unsigned int cmd,
 219                             unsigned long arg)
 220 {
 221         struct cros_ec_dev *ec = filp->private_data;
 222
 223         if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC)
 224                 return -ENOTTY;
 225
 226         switch (cmd) {
 227         case CROS_EC_DEV_IOCXCMD:
 228                 return ec_device_ioctl_xcmd(ec, (void __user *)arg);
 229         case CROS_EC_DEV_IOCRDMEM:
 230                 return ec_device_ioctl_readmem(ec, (void __user *)arg);
 231         }
 232
 233         return -ENOTTY;
 234 }
 235
 236 /* Module initialization */
 237 static const struct file_operations fops = {
 238         .open = ec_device_open,
 239         .release = ec_device_release,
 240         .read = ec_device_read,
 241         .unlocked_ioctl = ec_device_ioctl,
 242 #ifdef CONFIG_COMPAT
 243         .compat_ioctl = ec_device_ioctl,
 244 #endif
 245 };
 246
 247 static void cros_ec_class_release(struct device *dev)
 248 {
 249         kfree(to_cros_ec_dev(dev));
 250 }
 251
 252 static void cros_ec_sensors_register(struct cros_ec_dev *ec)
 253 {
 254         /*
 255          * Issue a command to get the number of sensor reported.
 256          * Build an array of sensors driver and register them all.
 257          */
 258         int ret, i, id, sensor_num;
 259         struct mfd_cell *sensor_cells;
 260         struct cros_ec_sensor_platform *sensor_platforms;
 261         int sensor_type[MOTIONSENSE_TYPE_MAX];
 262         struct ec_params_motion_sense *params;
 263         struct ec_response_motion_sense *resp;
 264         struct cros_ec_command *msg;
 265
 266         msg = kzalloc(sizeof(struct cros_ec_command) +
 267                       max(sizeof(*params), sizeof(*resp)), GFP_KERNEL);
 268         if (msg == NULL)
 269                 return;
 270
 271         msg->version = 2;
 272         msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
 273         msg->outsize = sizeof(*params);
 274         msg->insize = sizeof(*resp);
 275
 276         params = (struct ec_params_motion_sense *)msg->data;
 277         params->cmd = MOTIONSENSE_CMD_DUMP;
 278
 279         ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
 280         if (ret < 0 || msg->result != EC_RES_SUCCESS) {
 281                 dev_warn(ec->dev, "cannot get EC sensor information: %d/%d\n",
 282                          ret, msg->result);
 283                 goto error;
 284         }
 285
 286         resp = (struct ec_response_motion_sense *)msg->data;
 287         sensor_num = resp->dump.sensor_count;
 288         /* Allocate 1 extra sensors in FIFO are needed */
 289         sensor_cells = kcalloc(sensor_num + 1, sizeof(struct mfd_cell),
 290                                GFP_KERNEL);
 291         if (sensor_cells == NULL)
 292                 goto error;
 293
 294         sensor_platforms = kcalloc(sensor_num + 1,
 295                                    sizeof(struct cros_ec_sensor_platform),
 296                                    GFP_KERNEL);
 297         if (sensor_platforms == NULL)
 298                 goto error_platforms;
 299
 300         memset(sensor_type, 0, sizeof(sensor_type));
 301         id = 0;
 302         for (i = 0; i < sensor_num; i++) {
 303                 params->cmd = MOTIONSENSE_CMD_INFO;
 304                 params->info.sensor_num = i;
 305                 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
 306                 if (ret < 0 || msg->result != EC_RES_SUCCESS) {
 307                         dev_warn(ec->dev, "no info for EC sensor %d : %d/%d\n",
 308                                  i, ret, msg->result);
 309                         continue;
 310                 }
 311                 switch (resp->info.type) {
 312                 case MOTIONSENSE_TYPE_ACCEL:
 313                         sensor_cells[id].name = "cros-ec-accel";
 314                         break;
 315                 case MOTIONSENSE_TYPE_BARO:
 316                         sensor_cells[id].name = "cros-ec-baro";
 317                         break;
 318                 case MOTIONSENSE_TYPE_GYRO:
 319                         sensor_cells[id].name = "cros-ec-gyro";
 320                         break;
 321                 case MOTIONSENSE_TYPE_MAG:
 322                         sensor_cells[id].name = "cros-ec-mag";
 323                         break;
 324                 case MOTIONSENSE_TYPE_PROX:
 325                         sensor_cells[id].name = "cros-ec-prox";
 326                         break;
 327                 case MOTIONSENSE_TYPE_LIGHT:
 328                         sensor_cells[id].name = "cros-ec-light";
 329                         break;
 330                 case MOTIONSENSE_TYPE_ACTIVITY:
 331                         sensor_cells[id].name = "cros-ec-activity";
 332                         break;
 333                 default:
 334                         dev_warn(ec->dev, "unknown type %d\n", resp->info.type);
 335                         continue;
 336                 }
 337                 sensor_platforms[id].sensor_num = i;
 338                 sensor_cells[id].id = sensor_type[resp->info.type];
 339                 sensor_cells[id].platform_data = &sensor_platforms[id];
 340                 sensor_cells[id].pdata_size =
 341                         sizeof(struct cros_ec_sensor_platform);
 342
 343                 sensor_type[resp->info.type]++;
 344                 id++;
 345         }
 346
 347         if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
 348                 ec->has_kb_wake_angle = true;
 349
 350         if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
 351                 sensor_cells[id].name = "cros-ec-ring";
 352                 id++;
 353         }
 354
 355         ret = mfd_add_devices(ec->dev, 0, sensor_cells, id,
 356                               NULL, 0, NULL);
 357         if (ret)
 358                 dev_err(ec->dev, "failed to add EC sensors\n");
 359
 360         kfree(sensor_platforms);
 361 error_platforms:
 362         kfree(sensor_cells);
 363 error:
 364         kfree(msg);
 365 }
 366
 367 static const struct mfd_cell cros_ec_cec_cells[] = {
 368         { .name = "cros-ec-cec" }
 369 };
 370
 371 static const struct mfd_cell cros_ec_rtc_cells[] = {
 372         { .name = "cros-ec-rtc" }
 373 };
 374
 375 static const struct mfd_cell cros_usbpd_charger_cells[] = {
 376         { .name = "cros-usbpd-charger" },
 377         { .name = "cros-usbpd-logger" },
 378 };
 379
 380 static const struct mfd_cell cros_ec_platform_cells[] = {
 381         { .name = "cros-ec-debugfs" },
 382         { .name = "cros-ec-lightbar" },
 383         { .name = "cros-ec-sysfs" },
 384 };
 385
 386 static const struct mfd_cell cros_ec_vbc_cells[] = {
 387         { .name = "cros-ec-vbc" }
 388 };
 389
 390 static int ec_device_probe(struct platform_device *pdev)
 391 {
 392         int retval = -ENOMEM;
 393         struct device_node *node;
 394         struct device *dev = &pdev->dev;
 395         struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
 396         struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
 397
 398         if (!ec)
 399                 return retval;
 400
 401         dev_set_drvdata(dev, ec);
 402         ec->ec_dev = dev_get_drvdata(dev->parent);
 403         ec->dev = dev;
 404         ec->cmd_offset = ec_platform->cmd_offset;
 405         ec->features[0] = -1U; /* Not cached yet */
 406         ec->features[1] = -1U; /* Not cached yet */
 407         device_initialize(&ec->class_dev);
 408         cdev_init(&ec->cdev, &fops);
 409
 410         /* Check whether this is actually a Fingerprint MCU rather than an EC */
 411         if (cros_ec_check_features(ec, EC_FEATURE_FINGERPRINT)) {
 412                 dev_info(dev, "CrOS Fingerprint MCU detected.\n");
 413                 /*
 414                  * Help userspace differentiating ECs from FP MCU,
 415                  * regardless of the probing order.
 416                  */
 417                 ec_platform->ec_name = CROS_EC_DEV_FP_NAME;
 418         }
 419
 420         /*
 421          * Check whether this is actually an Integrated Sensor Hub (ISH)
 422          * rather than an EC.
 423          */
 424         if (cros_ec_check_features(ec, EC_FEATURE_ISH)) {
 425                 dev_info(dev, "CrOS ISH MCU detected.\n");
 426                 /*
 427                  * Help userspace differentiating ECs from ISH MCU,
 428                  * regardless of the probing order.
 429                  */
 430                 ec_platform->ec_name = CROS_EC_DEV_ISH_NAME;
 431         }
 432
 433         /* Check whether this is actually a Touchpad MCU rather than an EC */
 434         if (cros_ec_check_features(ec, EC_FEATURE_TOUCHPAD)) {
 435                 dev_info(dev, "CrOS Touchpad MCU detected.\n");
 436                 /*
 437                  * Help userspace differentiating ECs from TP MCU,
 438                  * regardless of the probing order.
 439                  */
 440                 ec_platform->ec_name = CROS_EC_DEV_TP_NAME;
 441         }
 442
 443         /*
 444          * Add the class device
 445          * Link to the character device for creating the /dev entry
 446          * in devtmpfs.
 447          */
 448         ec->class_dev.devt = MKDEV(ec_major, pdev->id);
 449         ec->class_dev.class = &cros_class;
 450         ec->class_dev.parent = dev;
 451         ec->class_dev.release = cros_ec_class_release;
 452
 453         retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
 454         if (retval) {
 455                 dev_err(dev, "dev_set_name failed => %d\n", retval);
 456                 goto failed;
 457         }
 458
 459         /* check whether this EC is a sensor hub. */
 460         if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE))
 461                 cros_ec_sensors_register(ec);
 462
 463         /* Check whether this EC instance has CEC host command support */
 464         if (cros_ec_check_features(ec, EC_FEATURE_CEC)) {
 465                 retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
 466                                          cros_ec_cec_cells,
 467                                          ARRAY_SIZE(cros_ec_cec_cells),
 468                                          NULL, 0, NULL);
 469                 if (retval)
 470                         dev_err(ec->dev,
 471                                 "failed to add cros-ec-cec device: %d\n",
 472                                 retval);
 473         }
 474
 475         /* Check whether this EC instance has RTC host command support */
 476         if (cros_ec_check_features(ec, EC_FEATURE_RTC)) {
 477                 retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
 478                                          cros_ec_rtc_cells,
 479                                          ARRAY_SIZE(cros_ec_rtc_cells),
 480                                          NULL, 0, NULL);
 481                 if (retval)
 482                         dev_err(ec->dev,
 483                                 "failed to add cros-ec-rtc device: %d\n",
 484                                 retval);
 485         }
 486
 487         /* Check whether this EC instance has the PD charge manager */
 488         if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
 489                 retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
 490                                          cros_usbpd_charger_cells,
 491                                          ARRAY_SIZE(cros_usbpd_charger_cells),
 492                                          NULL, 0, NULL);
 493                 if (retval)
 494                         dev_err(ec->dev,
 495                                 "failed to add cros-usbpd-charger device: %d\n",
 496                                 retval);
 497         }
 498
 499         /* We can now add the sysfs class, we know which parameter to show */
 500         retval = cdev_device_add(&ec->cdev, &ec->class_dev);
 501         if (retval) {
 502                 dev_err(dev, "cdev_device_add failed => %d\n", retval);
 503                 goto failed;
 504         }
 505
 506         retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
 507                                  cros_ec_platform_cells,
 508                                  ARRAY_SIZE(cros_ec_platform_cells),
 509                                  NULL, 0, NULL);
 510         if (retval)
 511                 dev_warn(ec->dev,
 512                          "failed to add cros-ec platform devices: %d\n",
 513                          retval);
 514
 515         /* Check whether this EC instance has a VBC NVRAM */
 516         node = ec->ec_dev->dev->of_node;
 517         if (of_property_read_bool(node, "google,has-vbc-nvram")) {
 518                 retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
 519                                          cros_ec_vbc_cells,
 520                                          ARRAY_SIZE(cros_ec_vbc_cells),
 521                                          NULL, 0, NULL);
 522                 if (retval)
 523                         dev_warn(ec->dev, "failed to add VBC devices: %d\n",
 524                                  retval);
 525         }
 526
 527         return 0;
 528
 529 failed:
 530         put_device(&ec->class_dev);
 531         return retval;
 532 }
 533
 534 static int ec_device_remove(struct platform_device *pdev)
 535 {
 536         struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 537
 538         mfd_remove_devices(ec->dev);
 539         cdev_del(&ec->cdev);
 540         device_unregister(&ec->class_dev);
 541         return 0;
 542 }
 543
 544 static const struct platform_device_id cros_ec_id[] = {
 545         { DRV_NAME, 0 },
 546         { /* sentinel */ }
 547 };
 548 MODULE_DEVICE_TABLE(platform, cros_ec_id);
 549
 550 static struct platform_driver cros_ec_dev_driver = {
 551         .driver = {
 552                 .name = DRV_NAME,
 553         },
 554         .id_table = cros_ec_id,
 555         .probe = ec_device_probe,
 556         .remove = ec_device_remove,
 557 };
 558
 559 static int __init cros_ec_dev_init(void)
 560 {
 561         int ret;
 562         dev_t dev = 0;
 563
 564         ret  = class_register(&cros_class);
 565         if (ret) {
 566                 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
 567                 return ret;
 568         }
 569
 570         /* Get a range of minor numbers (starting with 0) to work with */
 571         ret = alloc_chrdev_region(&dev, 0, CROS_MAX_DEV, CROS_EC_DEV_NAME);
 572         if (ret < 0) {
 573                 pr_err(CROS_EC_DEV_NAME ": alloc_chrdev_region() failed\n");
 574                 goto failed_chrdevreg;
 575         }
 576         ec_major = MAJOR(dev);
 577
 578         /* Register the driver */
 579         ret = platform_driver_register(&cros_ec_dev_driver);
 580         if (ret < 0) {
 581                 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
 582                 goto failed_devreg;
 583         }
 584         return 0;
 585
 586 failed_devreg:
 587         unregister_chrdev_region(MKDEV(ec_major, 0), CROS_MAX_DEV);
 588 failed_chrdevreg:
 589         class_unregister(&cros_class);
 590         return ret;
 591 }
 592
 593 static void __exit cros_ec_dev_exit(void)
 594 {
 595         platform_driver_unregister(&cros_ec_dev_driver);
 596         unregister_chrdev(ec_major, CROS_EC_DEV_NAME);
 597         class_unregister(&cros_class);
 598 }
 599
 600 module_init(cros_ec_dev_init);
 601 module_exit(cros_ec_dev_exit);
 602
 603 MODULE_ALIAS("platform:" DRV_NAME);
 604 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
 605 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
 606 MODULE_VERSION("1.0");
 607 MODULE_LICENSE("GPL");