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/dmi.h>
   9 #include <linux/kconfig.h>
  10 #include <linux/mfd/core.h>
  11 #include <linux/module.h>
  12 #include <linux/mod_devicetable.h>
  13 #include <linux/of.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/platform_data/cros_ec_chardev.h>
  16 #include <linux/platform_data/cros_ec_commands.h>
  17 #include <linux/platform_data/cros_ec_proto.h>
  18 #include <linux/slab.h>
  19
  20 #define DRV_NAME "cros-ec-dev"
  21
  22 static struct class cros_class = {
  23         .name           = "chromeos",
  24 };
  25
  26 /**
  27  * struct cros_feature_to_name - CrOS feature id to name/short description.
  28  * @id: The feature identifier.
  29  * @name: Device name associated with the feature id.
  30  * @desc: Short name that will be displayed.
  31  */
  32 struct cros_feature_to_name {
  33         unsigned int id;
  34         const char *name;
  35         const char *desc;
  36 };
  37
  38 /**
  39  * struct cros_feature_to_cells - CrOS feature id to mfd cells association.
  40  * @id: The feature identifier.
  41  * @mfd_cells: Pointer to the array of mfd cells that needs to be added.
  42  * @num_cells: Number of mfd cells into the array.
  43  */
  44 struct cros_feature_to_cells {
  45         unsigned int id;
  46         const struct mfd_cell *mfd_cells;
  47         unsigned int num_cells;
  48 };
  49
  50 static const struct cros_feature_to_name cros_mcu_devices[] = {
  51         {
  52                 .id     = EC_FEATURE_FINGERPRINT,
  53                 .name   = CROS_EC_DEV_FP_NAME,
  54                 .desc   = "Fingerprint",
  55         },
  56         {
  57                 .id     = EC_FEATURE_ISH,
  58                 .name   = CROS_EC_DEV_ISH_NAME,
  59                 .desc   = "Integrated Sensor Hub",
  60         },
  61         {
  62                 .id     = EC_FEATURE_SCP,
  63                 .name   = CROS_EC_DEV_SCP_NAME,
  64                 .desc   = "System Control Processor",
  65         },
  66         {
  67                 .id     = EC_FEATURE_TOUCHPAD,
  68                 .name   = CROS_EC_DEV_TP_NAME,
  69                 .desc   = "Touchpad",
  70         },
  71 };
  72
  73 static const struct mfd_cell cros_ec_cec_cells[] = {
  74         { .name = "cros-ec-cec", },
  75 };
  76
  77 static const struct mfd_cell cros_ec_gpio_cells[] = {
  78         { .name = "cros-ec-gpio", },
  79 };
  80
  81 static const struct mfd_cell cros_ec_rtc_cells[] = {
  82         { .name = "cros-ec-rtc", },
  83 };
  84
  85 static const struct mfd_cell cros_ec_sensorhub_cells[] = {
  86         { .name = "cros-ec-sensorhub", },
  87 };
  88
  89 static const struct mfd_cell cros_usbpd_charger_cells[] = {
  90         { .name = "cros-usbpd-charger", },
  91         { .name = "cros-usbpd-logger", },
  92 };
  93
  94 static const struct mfd_cell cros_usbpd_notify_cells[] = {
  95         { .name = "cros-usbpd-notify", },
  96 };
  97
  98 static const struct mfd_cell cros_ec_wdt_cells[] = {
  99         { .name = "cros-ec-wdt", }
 100 };
 101
 102 static const struct cros_feature_to_cells cros_subdevices[] = {
 103         {
 104                 .id             = EC_FEATURE_CEC,
 105                 .mfd_cells      = cros_ec_cec_cells,
 106                 .num_cells      = ARRAY_SIZE(cros_ec_cec_cells),
 107         },
 108         {
 109                 .id             = EC_FEATURE_GPIO,
 110                 .mfd_cells      = cros_ec_gpio_cells,
 111                 .num_cells      = ARRAY_SIZE(cros_ec_gpio_cells),
 112         },
 113         {
 114                 .id             = EC_FEATURE_RTC,
 115                 .mfd_cells      = cros_ec_rtc_cells,
 116                 .num_cells      = ARRAY_SIZE(cros_ec_rtc_cells),
 117         },
 118         {
 119                 .id             = EC_FEATURE_USB_PD,
 120                 .mfd_cells      = cros_usbpd_charger_cells,
 121                 .num_cells      = ARRAY_SIZE(cros_usbpd_charger_cells),
 122         },
 123         {
 124                 .id             = EC_FEATURE_HANG_DETECT,
 125                 .mfd_cells      = cros_ec_wdt_cells,
 126                 .num_cells      = ARRAY_SIZE(cros_ec_wdt_cells),
 127         },
 128 };
 129
 130 static const struct mfd_cell cros_ec_platform_cells[] = {
 131         { .name = "cros-ec-chardev", },
 132         { .name = "cros-ec-debugfs", },
 133         { .name = "cros-ec-sysfs", },
 134 };
 135
 136 static const struct mfd_cell cros_ec_pchg_cells[] = {
 137         { .name = "cros-ec-pchg", },
 138 };
 139
 140 static const struct mfd_cell cros_ec_lightbar_cells[] = {
 141         { .name = "cros-ec-lightbar", }
 142 };
 143
 144 static const struct mfd_cell cros_ec_vbc_cells[] = {
 145         { .name = "cros-ec-vbc", }
 146 };
 147
 148 static void cros_ec_class_release(struct device *dev)
 149 {
 150         kfree(to_cros_ec_dev(dev));
 151 }
 152
 153 static int ec_device_probe(struct platform_device *pdev)
 154 {
 155         int retval = -ENOMEM;
 156         struct device_node *node;
 157         struct device *dev = &pdev->dev;
 158         struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
 159         struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
 160         struct ec_response_pchg_count pchg_count;
 161         int i;
 162
 163         if (!ec)
 164                 return retval;
 165
 166         dev_set_drvdata(dev, ec);
 167         ec->ec_dev = dev_get_drvdata(dev->parent);
 168         ec->dev = dev;
 169         ec->cmd_offset = ec_platform->cmd_offset;
 170         ec->features.flags[0] = -1U; /* Not cached yet */
 171         ec->features.flags[1] = -1U; /* Not cached yet */
 172         device_initialize(&ec->class_dev);
 173
 174         for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) {
 175                 /*
 176                  * Check whether this is actually a dedicated MCU rather
 177                  * than an standard EC.
 178                  */
 179                 if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) {
 180                         dev_info(dev, "CrOS %s MCU detected\n",
 181                                  cros_mcu_devices[i].desc);
 182                         /*
 183                          * Help userspace differentiating ECs from other MCU,
 184                          * regardless of the probing order.
 185                          */
 186                         ec_platform->ec_name = cros_mcu_devices[i].name;
 187                         break;
 188                 }
 189         }
 190
 191         /*
 192          * Add the class device
 193          */
 194         ec->class_dev.class = &cros_class;
 195         ec->class_dev.parent = dev;
 196         ec->class_dev.release = cros_ec_class_release;
 197
 198         retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
 199         if (retval) {
 200                 dev_err(dev, "dev_set_name failed => %d\n", retval);
 201                 goto failed;
 202         }
 203
 204         retval = device_add(&ec->class_dev);
 205         if (retval)
 206                 goto failed;
 207
 208         /* check whether this EC is a sensor hub. */
 209         if (cros_ec_get_sensor_count(ec) > 0) {
 210                 retval = mfd_add_hotplug_devices(ec->dev,
 211                                 cros_ec_sensorhub_cells,
 212                                 ARRAY_SIZE(cros_ec_sensorhub_cells));
 213                 if (retval)
 214                         dev_err(ec->dev, "failed to add %s subdevice: %d\n",
 215                                 cros_ec_sensorhub_cells->name, retval);
 216         }
 217
 218         /*
 219          * The following subdevices can be detected by sending the
 220          * EC_FEATURE_GET_CMD Embedded Controller device.
 221          */
 222         for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) {
 223                 if (cros_ec_check_features(ec, cros_subdevices[i].id)) {
 224                         retval = mfd_add_hotplug_devices(ec->dev,
 225                                                 cros_subdevices[i].mfd_cells,
 226                                                 cros_subdevices[i].num_cells);
 227                         if (retval)
 228                                 dev_err(ec->dev,
 229                                         "failed to add %s subdevice: %d\n",
 230                                         cros_subdevices[i].mfd_cells->name,
 231                                         retval);
 232                 }
 233         }
 234
 235         /*
 236          * Lightbar is a special case. Newer devices support autodetection,
 237          * but older ones do not.
 238          */
 239         if (cros_ec_check_features(ec, EC_FEATURE_LIGHTBAR) ||
 240             dmi_match(DMI_PRODUCT_NAME, "Link")) {
 241                 retval = mfd_add_hotplug_devices(ec->dev,
 242                                         cros_ec_lightbar_cells,
 243                                         ARRAY_SIZE(cros_ec_lightbar_cells));
 244                 if (retval)
 245                         dev_warn(ec->dev, "failed to add lightbar: %d\n",
 246                                  retval);
 247         }
 248
 249         /*
 250          * The PD notifier driver cell is separate since it only needs to be
 251          * explicitly added on platforms that don't have the PD notifier ACPI
 252          * device entry defined.
 253          */
 254         if (IS_ENABLED(CONFIG_OF) && ec->ec_dev->dev->of_node) {
 255                 if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
 256                         retval = mfd_add_hotplug_devices(ec->dev,
 257                                         cros_usbpd_notify_cells,
 258                                         ARRAY_SIZE(cros_usbpd_notify_cells));
 259                         if (retval)
 260                                 dev_err(ec->dev,
 261                                         "failed to add PD notify devices: %d\n",
 262                                         retval);
 263                 }
 264         }
 265
 266         /*
 267          * The PCHG device cannot be detected by sending EC_FEATURE_GET_CMD, but
 268          * it can be detected by querying the number of peripheral chargers.
 269          */
 270         retval = cros_ec_cmd(ec->ec_dev, 0, EC_CMD_PCHG_COUNT, NULL, 0,
 271                              &pchg_count, sizeof(pchg_count));
 272         if (retval >= 0 && pchg_count.port_count) {
 273                 retval = mfd_add_hotplug_devices(ec->dev,
 274                                         cros_ec_pchg_cells,
 275                                         ARRAY_SIZE(cros_ec_pchg_cells));
 276                 if (retval)
 277                         dev_warn(ec->dev, "failed to add pchg: %d\n",
 278                                  retval);
 279         }
 280
 281         /*
 282          * The following subdevices cannot be detected by sending the
 283          * EC_FEATURE_GET_CMD to the Embedded Controller device.
 284          */
 285         retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells,
 286                                          ARRAY_SIZE(cros_ec_platform_cells));
 287         if (retval)
 288                 dev_warn(ec->dev,
 289                          "failed to add cros-ec platform devices: %d\n",
 290                          retval);
 291
 292         /* Check whether this EC instance has a VBC NVRAM */
 293         node = ec->ec_dev->dev->of_node;
 294         if (of_property_read_bool(node, "google,has-vbc-nvram")) {
 295                 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells,
 296                                                 ARRAY_SIZE(cros_ec_vbc_cells));
 297                 if (retval)
 298                         dev_warn(ec->dev, "failed to add VBC devices: %d\n",
 299                                  retval);
 300         }
 301
 302         return 0;
 303
 304 failed:
 305         put_device(&ec->class_dev);
 306         return retval;
 307 }
 308
 309 static void ec_device_remove(struct platform_device *pdev)
 310 {
 311         struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 312
 313         mfd_remove_devices(ec->dev);
 314         device_unregister(&ec->class_dev);
 315 }
 316
 317 static const struct platform_device_id cros_ec_id[] = {
 318         { DRV_NAME, 0 },
 319         { /* sentinel */ }
 320 };
 321 MODULE_DEVICE_TABLE(platform, cros_ec_id);
 322
 323 static struct platform_driver cros_ec_dev_driver = {
 324         .driver = {
 325                 .name = DRV_NAME,
 326         },
 327         .id_table = cros_ec_id,
 328         .probe = ec_device_probe,
 329         .remove_new = ec_device_remove,
 330 };
 331
 332 static int __init cros_ec_dev_init(void)
 333 {
 334         int ret;
 335
 336         ret  = class_register(&cros_class);
 337         if (ret) {
 338                 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
 339                 return ret;
 340         }
 341
 342         /* Register the driver */
 343         ret = platform_driver_register(&cros_ec_dev_driver);
 344         if (ret < 0) {
 345                 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
 346                 goto failed_devreg;
 347         }
 348         return 0;
 349
 350 failed_devreg:
 351         class_unregister(&cros_class);
 352         return ret;
 353 }
 354
 355 static void __exit cros_ec_dev_exit(void)
 356 {
 357         platform_driver_unregister(&cros_ec_dev_driver);
 358         class_unregister(&cros_class);
 359 }
 360
 361 module_init(cros_ec_dev_init);
 362 module_exit(cros_ec_dev_exit);
 363
 364 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
 365 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
 366 MODULE_VERSION("1.0");
 367 MODULE_LICENSE("GPL");