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/mfd/core.h>
   9 #include <linux/mfd/cros_ec.h>
  10 #include <linux/module.h>
  11 #include <linux/mod_devicetable.h>
  12 #include <linux/of_platform.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/platform_data/cros_ec_chardev.h>
  15 #include <linux/platform_data/cros_ec_commands.h>
  16 #include <linux/platform_data/cros_ec_proto.h>
  17 #include <linux/slab.h>
  18
  19 #define DRV_NAME "cros-ec-dev"
  20
  21 static struct class cros_class = {
  22         .owner          = THIS_MODULE,
  23         .name           = "chromeos",
  24 };
  25
  26 /**
  27  * 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  * 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 cros_feature_to_cells cros_subdevices[] = {
  91         {
  92                 .id             = EC_FEATURE_CEC,
  93                 .mfd_cells      = cros_ec_cec_cells,
  94                 .num_cells      = ARRAY_SIZE(cros_ec_cec_cells),
  95         },
  96         {
  97                 .id             = EC_FEATURE_RTC,
  98                 .mfd_cells      = cros_ec_rtc_cells,
  99                 .num_cells      = ARRAY_SIZE(cros_ec_rtc_cells),
 100         },
 101         {
 102                 .id             = EC_FEATURE_USB_PD,
 103                 .mfd_cells      = cros_usbpd_charger_cells,
 104                 .num_cells      = ARRAY_SIZE(cros_usbpd_charger_cells),
 105         },
 106 };
 107
 108 static const struct mfd_cell cros_ec_platform_cells[] = {
 109         { .name = "cros-ec-chardev", },
 110         { .name = "cros-ec-debugfs", },
 111         { .name = "cros-ec-lightbar", },
 112         { .name = "cros-ec-sysfs", },
 113 };
 114
 115 static const struct mfd_cell cros_ec_vbc_cells[] = {
 116         { .name = "cros-ec-vbc", }
 117 };
 118
 119 static void cros_ec_class_release(struct device *dev)
 120 {
 121         kfree(to_cros_ec_dev(dev));
 122 }
 123
 124 static int ec_device_probe(struct platform_device *pdev)
 125 {
 126         int retval = -ENOMEM;
 127         struct device_node *node;
 128         struct device *dev = &pdev->dev;
 129         struct cros_ec_platform *ec_platform = dev_get_platdata(dev);
 130         struct cros_ec_dev *ec = kzalloc(sizeof(*ec), GFP_KERNEL);
 131         int i;
 132
 133         if (!ec)
 134                 return retval;
 135
 136         dev_set_drvdata(dev, ec);
 137         ec->ec_dev = dev_get_drvdata(dev->parent);
 138         ec->dev = dev;
 139         ec->cmd_offset = ec_platform->cmd_offset;
 140         ec->features[0] = -1U; /* Not cached yet */
 141         ec->features[1] = -1U; /* Not cached yet */
 142         device_initialize(&ec->class_dev);
 143
 144         for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) {
 145                 /*
 146                  * Check whether this is actually a dedicated MCU rather
 147                  * than an standard EC.
 148                  */
 149                 if (cros_ec_check_features(ec, cros_mcu_devices[i].id)) {
 150                         dev_info(dev, "CrOS %s MCU detected\n",
 151                                  cros_mcu_devices[i].desc);
 152                         /*
 153                          * Help userspace differentiating ECs from other MCU,
 154                          * regardless of the probing order.
 155                          */
 156                         ec_platform->ec_name = cros_mcu_devices[i].name;
 157                         break;
 158                 }
 159         }
 160
 161         /*
 162          * Add the class device
 163          */
 164         ec->class_dev.class = &cros_class;
 165         ec->class_dev.parent = dev;
 166         ec->class_dev.release = cros_ec_class_release;
 167
 168         retval = dev_set_name(&ec->class_dev, "%s", ec_platform->ec_name);
 169         if (retval) {
 170                 dev_err(dev, "dev_set_name failed => %d\n", retval);
 171                 goto failed;
 172         }
 173
 174         retval = device_add(&ec->class_dev);
 175         if (retval)
 176                 goto failed;
 177
 178         /* check whether this EC is a sensor hub. */
 179         if (cros_ec_get_sensor_count(ec) > 0) {
 180                 retval = mfd_add_hotplug_devices(ec->dev,
 181                                 cros_ec_sensorhub_cells,
 182                                 ARRAY_SIZE(cros_ec_sensorhub_cells));
 183                 if (retval)
 184                         dev_err(ec->dev, "failed to add %s subdevice: %d\n",
 185                                 cros_ec_sensorhub_cells->name, retval);
 186         }
 187
 188         /*
 189          * The following subdevices can be detected by sending the
 190          * EC_FEATURE_GET_CMD Embedded Controller device.
 191          */
 192         for (i = 0; i < ARRAY_SIZE(cros_subdevices); i++) {
 193                 if (cros_ec_check_features(ec, cros_subdevices[i].id)) {
 194                         retval = mfd_add_hotplug_devices(ec->dev,
 195                                                 cros_subdevices[i].mfd_cells,
 196                                                 cros_subdevices[i].num_cells);
 197                         if (retval)
 198                                 dev_err(ec->dev,
 199                                         "failed to add %s subdevice: %d\n",
 200                                         cros_subdevices[i].mfd_cells->name,
 201                                         retval);
 202                 }
 203         }
 204
 205         /*
 206          * The following subdevices cannot be detected by sending the
 207          * EC_FEATURE_GET_CMD to the Embedded Controller device.
 208          */
 209         retval = mfd_add_hotplug_devices(ec->dev, cros_ec_platform_cells,
 210                                          ARRAY_SIZE(cros_ec_platform_cells));
 211         if (retval)
 212                 dev_warn(ec->dev,
 213                          "failed to add cros-ec platform devices: %d\n",
 214                          retval);
 215
 216         /* Check whether this EC instance has a VBC NVRAM */
 217         node = ec->ec_dev->dev->of_node;
 218         if (of_property_read_bool(node, "google,has-vbc-nvram")) {
 219                 retval = mfd_add_hotplug_devices(ec->dev, cros_ec_vbc_cells,
 220                                                 ARRAY_SIZE(cros_ec_vbc_cells));
 221                 if (retval)
 222                         dev_warn(ec->dev, "failed to add VBC devices: %d\n",
 223                                  retval);
 224         }
 225
 226         return 0;
 227
 228 failed:
 229         put_device(&ec->class_dev);
 230         return retval;
 231 }
 232
 233 static int ec_device_remove(struct platform_device *pdev)
 234 {
 235         struct cros_ec_dev *ec = dev_get_drvdata(&pdev->dev);
 236
 237         mfd_remove_devices(ec->dev);
 238         device_unregister(&ec->class_dev);
 239         return 0;
 240 }
 241
 242 static const struct platform_device_id cros_ec_id[] = {
 243         { DRV_NAME, 0 },
 244         { /* sentinel */ }
 245 };
 246 MODULE_DEVICE_TABLE(platform, cros_ec_id);
 247
 248 static struct platform_driver cros_ec_dev_driver = {
 249         .driver = {
 250                 .name = DRV_NAME,
 251         },
 252         .id_table = cros_ec_id,
 253         .probe = ec_device_probe,
 254         .remove = ec_device_remove,
 255 };
 256
 257 static int __init cros_ec_dev_init(void)
 258 {
 259         int ret;
 260
 261         ret  = class_register(&cros_class);
 262         if (ret) {
 263                 pr_err(CROS_EC_DEV_NAME ": failed to register device class\n");
 264                 return ret;
 265         }
 266
 267         /* Register the driver */
 268         ret = platform_driver_register(&cros_ec_dev_driver);
 269         if (ret < 0) {
 270                 pr_warn(CROS_EC_DEV_NAME ": can't register driver: %d\n", ret);
 271                 goto failed_devreg;
 272         }
 273         return 0;
 274
 275 failed_devreg:
 276         class_unregister(&cros_class);
 277         return ret;
 278 }
 279
 280 static void __exit cros_ec_dev_exit(void)
 281 {
 282         platform_driver_unregister(&cros_ec_dev_driver);
 283         class_unregister(&cros_class);
 284 }
 285
 286 module_init(cros_ec_dev_init);
 287 module_exit(cros_ec_dev_exit);
 288
 289 MODULE_ALIAS("platform:" DRV_NAME);
 290 MODULE_AUTHOR("Bill Richardson <wfrichar@chromium.org>");
 291 MODULE_DESCRIPTION("Userspace interface to the Chrome OS Embedded Controller");
 292 MODULE_VERSION("1.0");
 293 MODULE_LICENSE("GPL");