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