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_platform.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         .owner          = THIS_MODULE,
  24         .name           = "chromeos",
  25 };
  26
  27 /**
  28  * struct cros_feature_to_name - CrOS feature id to name/short description.
  29  * @id: The feature identifier.
  30  * @name: Device name associated with the feature id.
  31  * @desc: Short name that will be displayed.
  32  */
  33 struct cros_feature_to_name {
  34         unsigned int id;
  35         const char *name;
  36         const char *desc;
  37 };
  38
  39 /**
  40  * struct cros_feature_to_cells - CrOS feature id to mfd cells association.
  41  * @id: The feature identifier.
  42  * @mfd_cells: Pointer to the array of mfd cells that needs to be added.
  43  * @num_cells: Number of mfd cells into the array.
  44  */
  45 struct cros_feature_to_cells {
  46         unsigned int id;
  47         const struct mfd_cell *mfd_cells;
  48         unsigned int num_cells;
  49 };
  50
  51 static const struct cros_feature_to_name cros_mcu_devices[] = {
  52         {
  53                 .id     = EC_FEATURE_FINGERPRINT,
  54                 .name   = CROS_EC_DEV_FP_NAME,
  55                 .desc   = "Fingerprint",
  56         },
  57         {
  58                 .id     = EC_FEATURE_ISH,
  59                 .name   = CROS_EC_DEV_ISH_NAME,
  60                 .desc   = "Integrated Sensor Hub",
  61         },
  62         {
  63                 .id     = EC_FEATURE_SCP,
  64                 .name   = CROS_EC_DEV_SCP_NAME,
  65                 .desc   = "System Control Processor",
  66         },
  67         {
  68                 .id     = EC_FEATURE_SCP_C1,
  69                 .name   = CROS_EC_DEV_SCP_C1_NAME,
  70                 .desc   = "System Control Processor 2nd Core",
  71         },
  72         {
  73                 .id     = EC_FEATURE_TOUCHPAD,
  74                 .name   = CROS_EC_DEV_TP_NAME,
  75                 .desc   = "Touchpad",
  76         },
  77 };
  78
  79 static const struct mfd_cell cros_ec_cec_cells[] = {
  80         { .name = "cros-ec-cec", },
  81 };
  82
  83 static const struct mfd_cell cros_ec_rtc_cells[] = {
  84         { .name = "cros-ec-rtc", },
  85 };
  86
  87 static const struct mfd_cell cros_ec_sensorhub_cells[] = {
  88         { .name = "cros-ec-sensorhub", },
  89 };
  90
  91 static const struct mfd_cell cros_usbpd_charger_cells[] = {
  92         { .name = "cros-usbpd-charger", },
  93         { .name = "cros-usbpd-logger", },
  94 };
  95
  96 static const struct mfd_cell cros_usbpd_notify_cells[] = {
  97         { .name = "cros-usbpd-notify", },
  98 };
  99
 100 static const struct cros_feature_to_cells cros_subdevices[] = {
 101         {
 102                 .id             = EC_FEATURE_CEC,
 103                 .mfd_cells      = cros_ec_cec_cells,
 104                 .num_cells      = ARRAY_SIZE(cros_ec_cec_cells),
 105         },
 106         {
 107                 .id             = EC_FEATURE_RTC,
 108                 .mfd_cells      = cros_ec_rtc_cells,
 109                 .num_cells      = ARRAY_SIZE(cros_ec_rtc_cells),
 110         },
 111         {
 112                 .id             = EC_FEATURE_USB_PD,
 113                 .mfd_cells      = cros_usbpd_charger_cells,
 114                 .num_cells      = ARRAY_SIZE(cros_usbpd_charger_cells),
 115         },
 116 };
 117
 118 static const struct mfd_cell cros_ec_platform_cells[] = {
 119         { .name = "cros-ec-chardev", },
 120         { .name = "cros-ec-debugfs", },
 121         { .name = "cros-ec-sysfs", },
 122 };
 123
 124 static const struct mfd_cell cros_ec_pchg_cells[] = {
 125         { .name = "cros-ec-pchg", },
 126 };
 127
 128 static const struct mfd_cell cros_ec_lightbar_cells[] = {
 129         { .name = "cros-ec-lightbar", }
 130 };
 131
 132 static const struct mfd_cell cros_ec_vbc_cells[] = {
 133         { .name = "cros-ec-vbc", }
 134 };
 135
 136 static void cros_ec_class_release(struct device *dev)
 137 {
 138         kfree(to_cros_ec_dev(dev));
 139 }
 140
 141 static int ec_device_probe(struct platform_device *pdev)
 142 {
 143         int retval = -ENOMEM;
 144         struct device_node *node;
 145         struct device *dev = &pdev->dev;
 146         struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
 147         struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
 148         struct ec_response_pchg_count pchg_count;
 149         int i;
 150
 151         if (!ec)
 152                 return retval;
 153
 154         dev_set_drvdata(dev, ec);
 155         ec->ec_dev = dev_get_drvdata(dev->parent);
 156         ec->dev = dev;
 157         ec->cmd_offset = ec_platform->cmd_offset;
 158         ec->features.flags[0] = -1U; /* Not cached yet */
 159         ec->features.flags[1] = -1U; /* Not cached yet */
 160         device_initialize(&ec->class_dev);
 161
 162         for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) {
 163                 /*
 164                  * Check whether this is actually a dedicated MCU rather
 165                  * than an standard EC.
 166                  */
 167                 if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) {
 168                         dev_info(dev, "CrOS %s MCU detected\n",
 169                                  cros_mcu_devices[i].desc);
 170                         /*
 171                          * Help userspace differentiating ECs from other MCU,
 172                          * regardless of the probing order.
 173                          */
 174                         ec_platform->ec_name = cros_mcu_devices[i].name;
 175                         break;
 176                 }
 177         }
 178
 179         /*
 180          * Add the class device
 181          */
 182         ec->class_dev.class = &cros_class;
 183         ec->class_dev.parent = dev;
 184         ec->class_dev.release = cros_ec_class_release;
 185
 186         retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
 187         if (retval) {
 188                 dev_err(dev, "dev_set_name failed => %d\n", retval);
 189                 goto failed;
 190         }
 191
 192         retval = device_add(&ec->class_dev);
 193         if (retval)
 194                 goto failed;
 195
 196         /* check whether this EC is a sensor hub. */
 197         if (cros_ec_get_sensor_count(ec) > 0) {
 198                 retval = mfd_add_hotplug_devices(ec->dev,
 199                                 cros_ec_sensorhub_cells,
 200                                 ARRAY_SIZE(cros_ec_sensorhub_cells));
 201                 if (retval)
 202                         dev_err(ec->dev, "failed to add %s subdevice: %d\n",
 203                                 cros_ec_sensorhub_cells->name, retval);
 204         }
 205
 206         /*
 207          * The following subdevices can be detected by sending the
 208          * EC_FEATURE_GET_CMD Embedded Controller device.
 209          */
 210         for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) {
 211                 if (cros_ec_check_features(ec, cros_subdevices[i].id)) {
 212                         retval = mfd_add_hotplug_devices(ec->dev,
 213                                                 cros_subdevices[i].mfd_cells,
 214                                                 cros_subdevices[i].num_cells);
 215                         if (retval)
 216                                 dev_err(ec->dev,
 217                                         "failed to add %s subdevice: %d\n",
 218                                         cros_subdevices[i].mfd_cells->name,
 219                                         retval);
 220                 }
 221         }
 222
 223         /*
 224          * Lightbar is a special case. Newer devices support autodetection,
 225          * but older ones do not.
 226          */
 227         if (cros_ec_check_features(ec, EC_FEATURE_LIGHTBAR) ||
 228             dmi_match(DMI_PRODUCT_NAME, "Link")) {
 229                 retval = mfd_add_hotplug_devices(ec->dev,
 230                                         cros_ec_lightbar_cells,
 231                                         ARRAY_SIZE(cros_ec_lightbar_cells));
 232                 if (retval)
 233                         dev_warn(ec->dev, "failed to add lightbar: %d\n",
 234                                  retval);
 235         }
 236
 237         /*
 238          * The PD notifier driver cell is separate since it only needs to be
 239          * explicitly added on platforms that don't have the PD notifier ACPI
 240          * device entry defined.
 241          */
 242         if (IS_ENABLED(CONFIG_OF) && ec->ec_dev->dev->of_node) {
 243                 if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
 244                         retval = mfd_add_hotplug_devices(ec->dev,
 245                                         cros_usbpd_notify_cells,
 246                                         ARRAY_SIZE(cros_usbpd_notify_cells));
 247                         if (retval)
 248                                 dev_err(ec->dev,
 249                                         "failed to add PD notify devices: %d\n",
 250                                         retval);
 251                 }
 252         }
 253
 254         /*
 255          * The PCHG device cannot be detected by sending EC_FEATURE_GET_CMD, but
 256          * it can be detected by querying the number of peripheral chargers.
 257          */
 258         retval = cros_ec_cmd(ec->ec_dev, 0, EC_CMD_PCHG_COUNT, NULL, 0,
 259                              &pchg_count, sizeof(pchg_count));
 260         if (retval >= 0 && pchg_count.port_count) {
 261                 retval = mfd_add_hotplug_devices(ec->dev,
 262                                         cros_ec_pchg_cells,
 263                                         ARRAY_SIZE(cros_ec_pchg_cells));
 264                 if (retval)
 265                         dev_warn(ec->dev, "failed to add pchg: %d\n",
 266                                  retval);
 267         }
 268
 269         /*
 270          * The following subdevices cannot be detected by sending the
 271          * EC_FEATURE_GET_CMD to the Embedded Controller device.
 272          */
 273         retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells,
 274                                          ARRAY_SIZE(cros_ec_platform_cells));
 275         if (retval)
 276                 dev_warn(ec->dev,
 277                          "failed to add cros-ec platform devices: %d\n",
 278                          retval);
 279
 280         /* Check whether this EC instance has a VBC NVRAM */
 281         node = ec->ec_dev->dev->of_node;
 282         if (of_property_read_bool(node, "google,has-vbc-nvram")) {
 283                 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells,
 284                                                 ARRAY_SIZE(cros_ec_vbc_cells));
 285                 if (retval)
 286                         dev_warn(ec->dev, "failed to add VBC devices: %d\n",
 287                                  retval);
 288         }
 289
 290         return 0;
 291
 292 failed:
 293         put_device(&ec->class_dev);
 294         return retval;
 295 }
 296
 297 static int ec_device_remove(struct platform_device *pdev)
 298 {
 299         struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 300
 301         mfd_remove_devices(ec->dev);
 302         device_unregister(&ec->class_dev);
 303         return 0;
 304 }
 305
 306 static const struct platform_device_id cros_ec_id[] = {
 307         { DRV_NAME, 0 },
 308         { /* sentinel */ }
 309 };
 310 MODULE_DEVICE_TABLE(platform, cros_ec_id);
 311
 312 static struct platform_driver cros_ec_dev_driver = {
 313         .driver = {
 314                 .name = DRV_NAME,
 315         },
 316         .id_table = cros_ec_id,
 317         .probe = ec_device_probe,
 318         .remove = ec_device_remove,
 319 };
 320
 321 static int __init cros_ec_dev_init(void)
 322 {
 323         int ret;
 324
 325         ret  = class_register(&cros_class);
 326         if (ret) {
 327                 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
 328                 return ret;
 329         }
 330
 331         /* Register the driver */
 332         ret = platform_driver_register(&cros_ec_dev_driver);
 333         if (ret < 0) {
 334                 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
 335                 goto failed_devreg;
 336         }
 337         return 0;
 338
 339 failed_devreg:
 340         class_unregister(&cros_class);
 341         return ret;
 342 }
 343
 344 static void __exit cros_ec_dev_exit(void)
 345 {
 346         platform_driver_unregister(&cros_ec_dev_driver);
 347         class_unregister(&cros_class);
 348 }
 349
 350 module_init(cros_ec_dev_init);
 351 module_exit(cros_ec_dev_exit);
 352
 353 MODULE_AUTHOR("Bill Richardson <[email protected]>");
 354 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
 355 MODULE_VERSION("1.0");
 356 MODULE_LICENSE("GPL");