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