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