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/kconfig.h>
   9 #include <linux/mfd/core.h>
  10 #include <linux/mfd/cros_ec.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  * 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  * 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-lightbar", },
 117         { .name = "cros-ec-sysfs", },
 118 };
 119
 120 static const struct mfd_cell cros_ec_vbc_cells[] = {
 121         { .name = "cros-ec-vbc", }
 122 };
 123
 124 static void cros_ec_class_release(struct device *dev)
 125 {
 126         kfree(to_cros_ec_dev(dev));
 127 }
 128
 129 static int ec_device_probe(struct platform_device *pdev)
 130 {
 131         int retval = -ENOMEM;
 132         struct device_node *node;
 133         struct device *dev = &pdev->dev;
 134         struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
 135         struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
 136         int i;
 137
 138         if (!ec)
 139                 return retval;
 140
 141         dev_set_drvdata(dev, ec);
 142         ec->ec_dev = dev_get_drvdata(dev->parent);
 143         ec->dev = dev;
 144         ec->cmd_offset = ec_platform->cmd_offset;
 145         ec->features[0] = -1U; /* Not cached yet */
 146         ec->features[1] = -1U; /* Not cached yet */
 147         device_initialize(&ec->class_dev);
 148
 149         for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) {
 150                 /*
 151                  * Check whether this is actually a dedicated MCU rather
 152                  * than an standard EC.
 153                  */
 154                 if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) {
 155                         dev_info(dev, "CrOS %s MCU detected\n",
 156                                  cros_mcu_devices[i].desc);
 157                         /*
 158                          * Help userspace differentiating ECs from other MCU,
 159                          * regardless of the probing order.
 160                          */
 161                         ec_platform->ec_name = cros_mcu_devices[i].name;
 162                         break;
 163                 }
 164         }
 165
 166         /*
 167          * Add the class device
 168          */
 169         ec->class_dev.class = &cros_class;
 170         ec->class_dev.parent = dev;
 171         ec->class_dev.release = cros_ec_class_release;
 172
 173         retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
 174         if (retval) {
 175                 dev_err(dev, "dev_set_name failed => %d\n", retval);
 176                 goto failed;
 177         }
 178
 179         retval = device_add(&ec->class_dev);
 180         if (retval)
 181                 goto failed;
 182
 183         /* check whether this EC is a sensor hub. */
 184         if (cros_ec_get_sensor_count(ec) > 0) {
 185                 retval = mfd_add_hotplug_devices(ec->dev,
 186                                 cros_ec_sensorhub_cells,
 187                                 ARRAY_SIZE(cros_ec_sensorhub_cells));
 188                 if (retval)
 189                         dev_err(ec->dev, "failed to add %s subdevice: %d\n",
 190                                 cros_ec_sensorhub_cells->name, retval);
 191         }
 192
 193         /*
 194          * The following subdevices can be detected by sending the
 195          * EC_FEATURE_GET_CMD Embedded Controller device.
 196          */
 197         for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) {
 198                 if (cros_ec_check_features(ec, cros_subdevices[i].id)) {
 199                         retval = mfd_add_hotplug_devices(ec->dev,
 200                                                 cros_subdevices[i].mfd_cells,
 201                                                 cros_subdevices[i].num_cells);
 202                         if (retval)
 203                                 dev_err(ec->dev,
 204                                         "failed to add %s subdevice: %d\n",
 205                                         cros_subdevices[i].mfd_cells->name,
 206                                         retval);
 207                 }
 208         }
 209
 210         /*
 211          * The PD notifier driver cell is separate since it only needs to be
 212          * explicitly added on platforms that don't have the PD notifier ACPI
 213          * device entry defined.
 214          */
 215         if (IS_ENABLED(CONFIG_OF)) {
 216                 if (cros_ec_check_features(ec, EC_FEATURE_USB_PD)) {
 217                         retval = mfd_add_hotplug_devices(ec->dev,
 218                                         cros_usbpd_notify_cells,
 219                                         ARRAY_SIZE(cros_usbpd_notify_cells));
 220                         if (retval)
 221                                 dev_err(ec->dev,
 222                                         "failed to add PD notify devices: %d\n",
 223                                         retval);
 224                 }
 225         }
 226
 227         /*
 228          * The following subdevices cannot be detected by sending the
 229          * EC_FEATURE_GET_CMD to the Embedded Controller device.
 230          */
 231         retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells,
 232                                          ARRAY_SIZE(cros_ec_platform_cells));
 233         if (retval)
 234                 dev_warn(ec->dev,
 235                          "failed to add cros-ec platform devices: %d\n",
 236                          retval);
 237
 238         /* Check whether this EC instance has a VBC NVRAM */
 239         node = ec->ec_dev->dev->of_node;
 240         if (of_property_read_bool(node, "google,has-vbc-nvram")) {
 241                 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells,
 242                                                 ARRAY_SIZE(cros_ec_vbc_cells));
 243                 if (retval)
 244                         dev_warn(ec->dev, "failed to add VBC devices: %d\n",
 245                                  retval);
 246         }
 247
 248         return 0;
 249
 250 failed:
 251         put_device(&ec->class_dev);
 252         return retval;
 253 }
 254
 255 static int ec_device_remove(struct platform_device *pdev)
 256 {
 257         struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 258
 259         mfd_remove_devices(ec->dev);
 260         device_unregister(&ec->class_dev);
 261         return 0;
 262 }
 263
 264 static const struct platform_device_id cros_ec_id[] = {
 265         { DRV_NAME, 0 },
 266         { /* sentinel */ }
 267 };
 268 MODULE_DEVICE_TABLE(platform, cros_ec_id);
 269
 270 static struct platform_driver cros_ec_dev_driver = {
 271         .driver = {
 272                 .name = DRV_NAME,
 273         },
 274         .id_table = cros_ec_id,
 275         .probe = ec_device_probe,
 276         .remove = ec_device_remove,
 277 };
 278
 279 static int __init cros_ec_dev_init(void)
 280 {
 281         int ret;
 282
 283         ret  = class_register(&cros_class);
 284         if (ret) {
 285                 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
 286                 return ret;
 287         }
 288
 289         /* Register the driver */
 290         ret = platform_driver_register(&cros_ec_dev_driver);
 291         if (ret < 0) {
 292                 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
 293                 goto failed_devreg;
 294         }
 295         return 0;
 296
 297 failed_devreg:
 298         class_unregister(&cros_class);
 299         return ret;
 300 }
 301
 302 static void __exit cros_ec_dev_exit(void)
 303 {
 304         platform_driver_unregister(&cros_ec_dev_driver);
 305         class_unregister(&cros_class);
 306 }
 307
 308 module_init(cros_ec_dev_init);
 309 module_exit(cros_ec_dev_exit);
 310
 311 MODULE_ALIAS("platform:" DRV_NAME);
 312 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
 313 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
 314 MODULE_VERSION("1.0");
 315 MODULE_LICENSE("GPL");