drivers/mfd/cros_ec_dev.c

   1 /*
   2  * cros_ec_dev - expose the Chrome OS Embedded Controller to user-space
   3  *
   4  * Copyright (C) 2014 Google, Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/fs.h>
  21 #include <linux/mfd/core.h>
  22 #include <linux/module.h>
  23 #include <linux/mod_devicetable.h>
  24 #include <linux/of_platform.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/pm.h>
  27 #include <linux/slab.h>
  28 #include <linux/uaccess.h>
  29
  30 #include "cros_ec_dev.h"
  31
  32 #define DRV_NAME "cros-ec-dev"
  33
  34 /* Device variables */
  35 #define CROS_MAX_DEV 128
  36 static int ec_major;
  37
  38 static struct class cros_class = {
  39         .owner          = THIS_MODULE,
  40         .name           = "chromeos",
  41 };
  42
  43 /* Basic communication */
  44 static int ec_get_version(struct cros_ec_dev *ec, char *str, int maxlen)
  45 {
  46         struct ec_response_get_version *resp;
  47         static const char * const current_image_name[] = {
  48                 "unknown", "read-only", "read-write", "invalid",
  49         };
  50         struct cros_ec_command *msg;
  51         int ret;
  52
  53         msg = kmalloc(sizeof(*msg) + sizeof(*resp), GFP_KERNEL);
  54         if (!msg)
  55                 return -ENOMEM;
  56
  57         msg->version = 0;
  58         msg->command = EC_CMD_GET_VERSION + ec->cmd_offset;
  59         msg->insize = sizeof(*resp);
  60         msg->outsize = 0;
  61
  62         ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
  63         if (ret < 0)
  64                 goto exit;
  65
  66         if (msg->result != EC_RES_SUCCESS) {
  67                 snprintf(str, maxlen,
  68                          "%s\nUnknown EC version: EC returned %d\n",
  69                          CROS_EC_DEV_VERSION, msg->result);
  70                 ret = -EINVAL;
  71                 goto exit;
  72         }
  73
  74         resp = (struct ec_response_get_version *)msg->data;
  75         if (resp->current_image >= ARRAY_SIZE(current_image_name))
  76                 resp->current_image = 3; /* invalid */
  77
  78         snprintf(str, maxlen, "%s\n%s\n%s\n%s\n", CROS_EC_DEV_VERSION,
  79                  resp->version_string_ro, resp->version_string_rw,
  80                  current_image_name[resp->current_image]);
  81
  82         ret = 0;
  83 exit:
  84         kfree(msg);
  85         return ret;
  86 }
  87
  88 static int cros_ec_check_features(struct cros_ec_dev *ec, int feature)
  89 {
  90         struct cros_ec_command *msg;
  91         int ret;
  92
  93         if (ec->features[0] == -1U && ec->features[1] == -1U) {
  94                 /* features bitmap not read yet */
  95
  96                 msg = kmalloc(sizeof(*msg) + sizeof(ec->features), GFP_KERNEL);
  97                 if (!msg)
  98                         return -ENOMEM;
  99
 100                 msg->version = 0;
 101                 msg->command = EC_CMD_GET_FEATURES + ec->cmd_offset;
 102                 msg->insize = sizeof(ec->features);
 103                 msg->outsize = 0;
 104
 105                 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
 106                 if (ret < 0 || msg->result != EC_RES_SUCCESS) {
 107                         dev_warn(ec->dev, "cannot get EC features: %d/%d\n",
 108                                  ret, msg->result);
 109                         memset(ec->features, 0, sizeof(ec->features));
 110                 } else {
 111                         memcpy(ec->features, msg->data, sizeof(ec->features));
 112                 }
 113
 114                 dev_dbg(ec->dev, "EC features %08x %08x\n",
 115                         ec->features[0], ec->features[1]);
 116
 117                 kfree(msg);
 118         }
 119
 120         return ec->features[feature / 32] & EC_FEATURE_MASK_0(feature);
 121 }
 122
 123 /* Device file ops */
 124 static int ec_device_open(struct inode *inode, struct file *filp)
 125 {
 126         struct cros_ec_dev *ec = container_of(inode->i_cdev,
 127                                               struct cros_ec_dev, cdev);
 128         filp->private_data = ec;
 129         nonseekable_open(inode, filp);
 130         return 0;
 131 }
 132
 133 static int ec_device_release(struct inode *inode, struct file *filp)
 134 {
 135         return 0;
 136 }
 137
 138 static ssize_t ec_device_read(struct file *filp, char __user *buffer,
 139                               size_t length, loff_t *offset)
 140 {
 141         struct cros_ec_dev *ec = filp->private_data;
 142         char msg[sizeof(struct ec_response_get_version) +
 143                  sizeof(CROS_EC_DEV_VERSION)];
 144         size_t count;
 145         int ret;
 146
 147         if (*offset != 0)
 148                 return 0;
 149
 150         ret = ec_get_version(ec, msg, sizeof(msg));
 151         if (ret)
 152                 return ret;
 153
 154         count = min(length, strlen(msg));
 155
 156         if (copy_to_user(buffer, msg, count))
 157                 return -EFAULT;
 158
 159         *offset = count;
 160         return count;
 161 }
 162
 163 /* Ioctls */
 164 static long ec_device_ioctl_xcmd(struct cros_ec_dev *ec, void __user *arg)
 165 {
 166         long ret;
 167         struct cros_ec_command u_cmd;
 168         struct cros_ec_command *s_cmd;
 169
 170         if (copy_from_user(&u_cmd, arg, sizeof(u_cmd)))
 171                 return -EFAULT;
 172
 173         if ((u_cmd.outsize > EC_MAX_MSG_BYTES) ||
 174             (u_cmd.insize > EC_MAX_MSG_BYTES))
 175                 return -EINVAL;
 176
 177         s_cmd = kmalloc(sizeof(*s_cmd) + max(u_cmd.outsize, u_cmd.insize),
 178                         GFP_KERNEL);
 179         if (!s_cmd)
 180                 return -ENOMEM;
 181
 182         if (copy_from_user(s_cmd, arg, sizeof(*s_cmd) + u_cmd.outsize)) {
 183                 ret = -EFAULT;
 184                 goto exit;
 185         }
 186
 187         if (u_cmd.outsize != s_cmd->outsize ||
 188             u_cmd.insize != s_cmd->insize) {
 189                 ret = -EINVAL;
 190                 goto exit;
 191         }
 192
 193         s_cmd->command += ec->cmd_offset;
 194         ret = cros_ec_cmd_xfer(ec->ec_dev, s_cmd);
 195         /* Only copy data to userland if data was received. */
 196         if (ret < 0)
 197                 goto exit;
 198
 199         if (copy_to_user(arg, s_cmd, sizeof(*s_cmd) + s_cmd->insize))
 200                 ret = -EFAULT;
 201 exit:
 202         kfree(s_cmd);
 203         return ret;
 204 }
 205
 206 static long ec_device_ioctl_readmem(struct cros_ec_dev *ec, void __user *arg)
 207 {
 208         struct cros_ec_device *ec_dev = ec->ec_dev;
 209         struct cros_ec_readmem s_mem = { };
 210         long num;
 211
 212         /* Not every platform supports direct reads */
 213         if (!ec_dev->cmd_readmem)
 214                 return -ENOTTY;
 215
 216         if (copy_from_user(&s_mem, arg, sizeof(s_mem)))
 217                 return -EFAULT;
 218
 219         num = ec_dev->cmd_readmem(ec_dev, s_mem.offset, s_mem.bytes,
 220                                   s_mem.buffer);
 221         if (num <= 0)
 222                 return num;
 223
 224         if (copy_to_user((void __user *)arg, &s_mem, sizeof(s_mem)))
 225                 return -EFAULT;
 226
 227         return num;
 228 }
 229
 230 static long ec_device_ioctl(struct file *filp, unsigned int cmd,
 231                             unsigned long arg)
 232 {
 233         struct cros_ec_dev *ec = filp->private_data;
 234
 235         if (_IOC_TYPE(cmd) != CROS_EC_DEV_IOC)
 236                 return -ENOTTY;
 237
 238         switch (cmd) {
 239         case CROS_EC_DEV_IOCXCMD:
 240                 return ec_device_ioctl_xcmd(ec, (void __user *)arg);
 241         case CROS_EC_DEV_IOCRDMEM:
 242                 return ec_device_ioctl_readmem(ec, (void __user *)arg);
 243         }
 244
 245         return -ENOTTY;
 246 }
 247
 248 /* Module initialization */
 249 static const struct file_operations fops = {
 250         .open = ec_device_open,
 251         .release = ec_device_release,
 252         .read = ec_device_read,
 253         .unlocked_ioctl = ec_device_ioctl,
 254 #ifdef CONFIG_COMPAT
 255         .compat_ioctl = ec_device_ioctl,
 256 #endif
 257 };
 258
 259 static void cros_ec_class_release(struct device *dev)
 260 {
 261         kfree(to_cros_ec_dev(dev));
 262 }
 263
 264 static void cros_ec_sensors_register(struct cros_ec_dev *ec)
 265 {
 266         /*
 267          * Issue a command to get the number of sensor reported.
 268          * Build an array of sensors driver and register them all.
 269          */
 270         int ret, i, id, sensor_num;
 271         struct mfd_cell *sensor_cells;
 272         struct cros_ec_sensor_platform *sensor_platforms;
 273         int sensor_type[MOTIONSENSE_TYPE_MAX];
 274         struct ec_params_motion_sense *params;
 275         struct ec_response_motion_sense *resp;
 276         struct cros_ec_command *msg;
 277
 278         msg = kzalloc(sizeof(struct cros_ec_command) +
 279                       max(sizeof(*params), sizeof(*resp)), GFP_KERNEL);
 280         if (msg == NULL)
 281                 return;
 282
 283         msg->version = 2;
 284         msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
 285         msg->outsize = sizeof(*params);
 286         msg->insize = sizeof(*resp);
 287
 288         params = (struct ec_params_motion_sense *)msg->data;
 289         params->cmd = MOTIONSENSE_CMD_DUMP;
 290
 291         ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
 292         if (ret < 0 || msg->result != EC_RES_SUCCESS) {
 293                 dev_warn(ec->dev, "cannot get EC sensor information: %d/%d\n",
 294                          ret, msg->result);
 295                 goto error;
 296         }
 297
 298         resp = (struct ec_response_motion_sense *)msg->data;
 299         sensor_num = resp->dump.sensor_count;
 300         /* Allocate 1 extra sensors in FIFO are needed */
 301         sensor_cells = kcalloc(sensor_num + 1, sizeof(struct mfd_cell),
 302                                GFP_KERNEL);
 303         if (sensor_cells == NULL)
 304                 goto error;
 305
 306         sensor_platforms = kcalloc(sensor_num + 1,
 307                                    sizeof(struct cros_ec_sensor_platform),
 308                                    GFP_KERNEL);
 309         if (sensor_platforms == NULL)
 310                 goto error_platforms;
 311
 312         memset(sensor_type, 0, sizeof(sensor_type));
 313         id = 0;
 314         for (i = 0; i < sensor_num; i++) {
 315                 params->cmd = MOTIONSENSE_CMD_INFO;
 316                 params->info.sensor_num = i;
 317                 ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
 318                 if (ret < 0 || msg->result != EC_RES_SUCCESS) {
 319                         dev_warn(ec->dev, "no info for EC sensor %d : %d/%d\n",
 320                                  i, ret, msg->result);
 321                         continue;
 322                 }
 323                 switch (resp->info.type) {
 324                 case MOTIONSENSE_TYPE_ACCEL:
 325                         sensor_cells[id].name = "cros-ec-accel";
 326                         break;
 327                 case MOTIONSENSE_TYPE_BARO:
 328                         sensor_cells[id].name = "cros-ec-baro";
 329                         break;
 330                 case MOTIONSENSE_TYPE_GYRO:
 331                         sensor_cells[id].name = "cros-ec-gyro";
 332                         break;
 333                 case MOTIONSENSE_TYPE_MAG:
 334                         sensor_cells[id].name = "cros-ec-mag";
 335                         break;
 336                 case MOTIONSENSE_TYPE_PROX:
 337                         sensor_cells[id].name = "cros-ec-prox";
 338                         break;
 339                 case MOTIONSENSE_TYPE_LIGHT:
 340                         sensor_cells[id].name = "cros-ec-light";
 341                         break;
 342                 case MOTIONSENSE_TYPE_ACTIVITY:
 343                         sensor_cells[id].name = "cros-ec-activity";
 344                         break;
 345                 default:
 346                         dev_warn(ec->dev, "unknown type %d\n", resp->info.type);
 347                         continue;
 348                 }
 349                 sensor_platforms[id].sensor_num = i;
 350                 sensor_cells[id].id = sensor_type[resp->info.type];
 351                 sensor_cells[id].platform_data = &sensor_platforms[id];
 352                 sensor_cells[id].pdata_size =
 353                         sizeof(struct cros_ec_sensor_platform);
 354
 355                 sensor_type[resp->info.type]++;
 356                 id++;
 357         }
 358
 359         if (sensor_type[MOTIONSENSE_TYPE_ACCEL] >= 2)
 360                 ec->has_kb_wake_angle = true;
 361
 362         if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE_FIFO)) {
 363                 sensor_cells[id].name = "cros-ec-ring";
 364                 id++;
 365         }
 366
 367         ret = mfd_add_devices(ec->dev, 0, sensor_cells, id,
 368                               NULL, 0, NULL);
 369         if (ret)
 370                 dev_err(ec->dev, "failed to add EC sensors\n");
 371
 372         kfree(sensor_platforms);
 373 error_platforms:
 374         kfree(sensor_cells);
 375 error:
 376         kfree(msg);
 377 }
 378
 379 static const struct mfd_cell cros_ec_cec_cells[] = {
 380         { .name = "cros-ec-cec" }
 381 };
 382
 383 static const struct mfd_cell cros_ec_rtc_cells[] = {
 384         { .name = "cros-ec-rtc" }
 385 };
 386
 387 static const struct mfd_cell cros_usbpd_charger_cells[] = {
 388         { .name = "cros-usbpd-charger" },
 389         { .name = "cros-usbpd-logger" },
 390 };
 391
 392 static const struct mfd_cell cros_ec_platform_cells[] = {
 393         { .name = "cros-ec-debugfs" },
 394         { .name = "cros-ec-lightbar" },
 395         { .name = "cros-ec-sysfs" },
 396 };
 397
 398 static const struct mfd_cell cros_ec_vbc_cells[] = {
 399         { .name = "cros-ec-vbc" }
 400 };
 401
 402 static int ec_device_probe(struct platform_device *pdev)
 403 {
 404         int retval = -ENOMEM;
 405         struct device_node *node;
 406         struct device *dev = &pdev->dev;
 407         struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
 408         struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
 409
 410         if (!ec)
 411                 return retval;
 412
 413         dev_set_drvdata(dev, ec);
 414         ec->ec_dev = dev_get_drvdata(dev->parent);
 415         ec->dev = dev;
 416         ec->cmd_offset = ec_platform->cmd_offset;
 417         ec->features[0] = -1U; /* Not cached yet */
 418         ec->features[1] = -1U; /* Not cached yet */
 419         device_initialize(&ec->class_dev);
 420         cdev_init(&ec->cdev, &fops);
 421
 422         /* Check whether this is actually a Fingerprint MCU rather than an EC */
 423         if (cros_ec_check_features(ec, EC_FEATURE_FINGERPRINT)) {
 424                 dev_info(dev, "CrOS Fingerprint MCU detected.\n");
 425                 /*
 426                  * Help userspace differentiating ECs from FP MCU,
 427                  * regardless of the probing order.
 428                  */
 429                 ec_platform->ec_name = CROS_EC_DEV_FP_NAME;
 430         }
 431
 432         /*
 433          * Check whether this is actually an Integrated Sensor Hub (ISH)
 434          * rather than an EC.
 435          */
 436         if (cros_ec_check_features(ec, EC_FEATURE_ISH)) {
 437                 dev_info(dev, "CrOS ISH MCU detected.\n");
 438                 /*
 439                  * Help userspace differentiating ECs from ISH MCU,
 440                  * regardless of the probing order.
 441                  */
 442                 ec_platform->ec_name = CROS_EC_DEV_ISH_NAME;
 443         }
 444
 445         /* Check whether this is actually a Touchpad MCU rather than an EC */
 446         if (cros_ec_check_features(ec, EC_FEATURE_TOUCHPAD)) {
 447                 dev_info(dev, "CrOS Touchpad MCU detected.\n");
 448                 /*
 449                  * Help userspace differentiating ECs from TP MCU,
 450                  * regardless of the probing order.
 451                  */
 452                 ec_platform->ec_name = CROS_EC_DEV_TP_NAME;
 453         }
 454
 455         /*
 456          * Add the class device
 457          * Link to the character device for creating the /dev entry
 458          * in devtmpfs.
 459          */
 460         ec->class_dev.devt = MKDEV(ec_major, pdev->id);
 461         ec->class_dev.class = &cros_class;
 462         ec->class_dev.parent = dev;
 463         ec->class_dev.release = cros_ec_class_release;
 464
 465         retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
 466         if (retval) {
 467                 dev_err(dev, "dev_set_name failed => %d\n", retval);
 468                 goto failed;
 469         }
 470
 471         /* check whether this EC is a sensor hub. */
 472         if (cros_ec_check_features(ec, EC_FEATURE_MOTION_SENSE))
 473                 cros_ec_sensors_register(ec);
 474
 475         /* Check whether this EC instance has CEC host command support */
 476         if (cros_ec_check_features(ec, EC_FEATURE_CEC)) {
 477                 retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
 478                                          cros_ec_cec_cells,
 479                                          ARRAY_SIZE(cros_ec_cec_cells),
 480                                          NULL, 0, NULL);
 481                 if (retval)
 482                         dev_err(ec->dev,
 483                                 "failed to add cros-ec-cec device: %d\n",
 484                                 retval);
 485         }
 486
 487         /* Check whether this EC instance has RTC host command support */
 488         if (cros_ec_check_features(ec, EC_FEATURE_RTC)) {
 489                 retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
 490                                          cros_ec_rtc_cells,
 491                                          ARRAY_SIZE(cros_ec_rtc_cells),
 492                                          NULL, 0, NULL);
 493                 if (retval)
 494                         dev_err(ec->dev,
 495                                 "failed to add cros-ec-rtc device: %d\n",
 496                                 retval);
 497         }
 498
 499         /* Check whether this EC instance has the PD charge manager */
 500         if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
 501                 retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
 502                                          cros_usbpd_charger_cells,
 503                                          ARRAY_SIZE(cros_usbpd_charger_cells),
 504                                          NULL, 0, NULL);
 505                 if (retval)
 506                         dev_err(ec->dev,
 507                                 "failed to add cros-usbpd-charger device: %d\n",
 508                                 retval);
 509         }
 510
 511         /* We can now add the sysfs class, we know which parameter to show */
 512         retval = cdev_device_add(&ec->cdev, &ec->class_dev);
 513         if (retval) {
 514                 dev_err(dev, "cdev_device_add failed => %d\n", retval);
 515                 goto failed;
 516         }
 517
 518         retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
 519                                  cros_ec_platform_cells,
 520                                  ARRAY_SIZE(cros_ec_platform_cells),
 521                                  NULL, 0, NULL);
 522         if (retval)
 523                 dev_warn(ec->dev,
 524                          "failed to add cros-ec platform devices: %d\n",
 525                          retval);
 526
 527         /* Check whether this EC instance has a VBC NVRAM */
 528         node = ec->ec_dev->dev->of_node;
 529         if (of_property_read_bool(node, "google,has-vbc-nvram")) {
 530                 retval = mfd_add_devices(ec->dev, PLATFORM_DEVID_AUTO,
 531                                          cros_ec_vbc_cells,
 532                                          ARRAY_SIZE(cros_ec_vbc_cells),
 533                                          NULL, 0, NULL);
 534                 if (retval)
 535                         dev_warn(ec->dev, "failed to add VBC devices: %d\n",
 536                                  retval);
 537         }
 538
 539         return 0;
 540
 541 failed:
 542         put_device(&ec->class_dev);
 543         return retval;
 544 }
 545
 546 static int ec_device_remove(struct platform_device *pdev)
 547 {
 548         struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 549
 550         mfd_remove_devices(ec->dev);
 551         cdev_del(&ec->cdev);
 552         device_unregister(&ec->class_dev);
 553         return 0;
 554 }
 555
 556 static const struct platform_device_id cros_ec_id[] = {
 557         { DRV_NAME, 0 },
 558         { /* sentinel */ }
 559 };
 560 MODULE_DEVICE_TABLE(platform, cros_ec_id);
 561
 562 static struct platform_driver cros_ec_dev_driver = {
 563         .driver = {
 564                 .name = DRV_NAME,
 565         },
 566         .id_table = cros_ec_id,
 567         .probe = ec_device_probe,
 568         .remove = ec_device_remove,
 569 };
 570
 571 static int __init cros_ec_dev_init(void)
 572 {
 573         int ret;
 574         dev_t dev = 0;
 575
 576         ret  = class_register(&cros_class);
 577         if (ret) {
 578                 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
 579                 return ret;
 580         }
 581
 582         /* Get a range of minor numbers (starting with 0) to work with */
 583         ret = alloc_chrdev_region(&dev, 0, CROS_MAX_DEV, CROS_EC_DEV_NAME);
 584         if (ret < 0) {
 585                 pr_err(CROS_EC_DEV_NAME ": alloc_chrdev_region() failed\n");
 586                 goto failed_chrdevreg;
 587         }
 588         ec_major = MAJOR(dev);
 589
 590         /* Register the driver */
 591         ret = platform_driver_register(&cros_ec_dev_driver);
 592         if (ret < 0) {
 593                 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
 594                 goto failed_devreg;
 595         }
 596         return 0;
 597
 598 failed_devreg:
 599         unregister_chrdev_region(MKDEV(ec_major, 0), CROS_MAX_DEV);
 600 failed_chrdevreg:
 601         class_unregister(&cros_class);
 602         return ret;
 603 }
 604
 605 static void __exit cros_ec_dev_exit(void)
 606 {
 607         platform_driver_unregister(&cros_ec_dev_driver);
 608         unregister_chrdev(ec_major, CROS_EC_DEV_NAME);
 609         class_unregister(&cros_class);
 610 }
 611
 612 module_init(cros_ec_dev_init);
 613 module_exit(cros_ec_dev_exit);
 614
 615 MODULE_ALIAS("platform:" DRV_NAME);
 616 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
 617 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
 618 MODULE_VERSION("1.0");
 619 MODULE_LICENSE("GPL");