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