drivers/usb/typec/bus.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Bus for USB Type-C Alternate Modes
   4  *
   5  * Copyright (C) 2018 Intel Corporation
   6  * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
   7  */
   8
   9 #include <linux/usb/pd_vdo.h>
  10
  11 #include "bus.h"
  12
  13 static inline int
  14 typec_altmode_set_mux(struct altmode *alt, unsigned long conf, void *data)
  15 {
  16         struct typec_mux_state state;
  17
  18         if (!alt->mux)
  19                 return 0;
  20
  21         state.alt = &alt->adev;
  22         state.mode = conf;
  23         state.data = data;
  24
  25         return alt->mux->set(alt->mux, &state);
  26 }
  27
  28 static int typec_altmode_set_state(struct typec_altmode *adev,
  29                                    unsigned long conf, void *data)
  30 {
  31         bool is_port = is_typec_port(adev->dev.parent);
  32         struct altmode *port_altmode;
  33
  34         port_altmode = is_port ? to_altmode(adev) : to_altmode(adev)->partner;
  35
  36         return typec_altmode_set_mux(port_altmode, conf, data);
  37 }
  38
  39 /* -------------------------------------------------------------------------- */
  40 /* Common API */
  41
  42 /**
  43  * typec_altmode_notify - Communication between the OS and alternate mode driver
  44  * @adev: Handle to the alternate mode
  45  * @conf: Alternate mode specific configuration value
  46  * @data: Alternate mode specific data
  47  *
  48  * The primary purpose for this function is to allow the alternate mode drivers
  49  * to tell which pin configuration has been negotiated with the partner. That
  50  * information will then be used for example to configure the muxes.
  51  * Communication to the other direction is also possible, and low level device
  52  * drivers can also send notifications to the alternate mode drivers. The actual
  53  * communication will be specific for every SVID.
  54  */
  55 int typec_altmode_notify(struct typec_altmode *adev,
  56                          unsigned long conf, void *data)
  57 {
  58         bool is_port;
  59         struct altmode *altmode;
  60         struct altmode *partner;
  61         int ret;
  62
  63         if (!adev)
  64                 return 0;
  65
  66         altmode = to_altmode(adev);
  67
  68         if (!altmode->partner)
  69                 return -ENODEV;
  70
  71         is_port = is_typec_port(adev->dev.parent);
  72         partner = altmode->partner;
  73
  74         ret = typec_altmode_set_mux(is_port ? altmode : partner, conf, data);
  75         if (ret)
  76                 return ret;
  77
  78         if (partner->adev.ops && partner->adev.ops->notify)
  79                 return partner->adev.ops->notify(&partner->adev, conf, data);
  80
  81         return 0;
  82 }
  83 EXPORT_SYMBOL_GPL(typec_altmode_notify);
  84
  85 /**
  86  * typec_altmode_enter - Enter Mode
  87  * @adev: The alternate mode
  88  * @vdo: VDO for the Enter Mode command
  89  *
  90  * The alternate mode drivers use this function to enter mode. The port drivers
  91  * use this to inform the alternate mode drivers that the partner has initiated
  92  * Enter Mode command. If the alternate mode does not require VDO, @vdo must be
  93  * NULL.
  94  */
  95 int typec_altmode_enter(struct typec_altmode *adev, u32 *vdo)
  96 {
  97         struct altmode *partner = to_altmode(adev)->partner;
  98         struct typec_altmode *pdev = &partner->adev;
  99         int ret;
 100
 101         if (!adev || adev->active)
 102                 return 0;
 103
 104         if (!pdev->ops || !pdev->ops->enter)
 105                 return -EOPNOTSUPP;
 106
 107         if (is_typec_port(pdev->dev.parent) && !pdev->active)
 108                 return -EPERM;
 109
 110         /* Moving to USB Safe State */
 111         ret = typec_altmode_set_state(adev, TYPEC_STATE_SAFE, NULL);
 112         if (ret)
 113                 return ret;
 114
 115         /* Enter Mode */
 116         return pdev->ops->enter(pdev, vdo);
 117 }
 118 EXPORT_SYMBOL_GPL(typec_altmode_enter);
 119
 120 /**
 121  * typec_altmode_exit - Exit Mode
 122  * @adev: The alternate mode
 123  *
 124  * The partner of @adev has initiated Exit Mode command.
 125  */
 126 int typec_altmode_exit(struct typec_altmode *adev)
 127 {
 128         struct altmode *partner = to_altmode(adev)->partner;
 129         struct typec_altmode *pdev = &partner->adev;
 130         int ret;
 131
 132         if (!adev || !adev->active)
 133                 return 0;
 134
 135         if (!pdev->ops || !pdev->ops->enter)
 136                 return -EOPNOTSUPP;
 137
 138         /* Moving to USB Safe State */
 139         ret = typec_altmode_set_state(adev, TYPEC_STATE_SAFE, NULL);
 140         if (ret)
 141                 return ret;
 142
 143         /* Exit Mode command */
 144         return pdev->ops->exit(pdev);
 145 }
 146 EXPORT_SYMBOL_GPL(typec_altmode_exit);
 147
 148 /**
 149  * typec_altmode_attention - Attention command
 150  * @adev: The alternate mode
 151  * @vdo: VDO for the Attention command
 152  *
 153  * Notifies the partner of @adev about Attention command.
 154  */
 155 void typec_altmode_attention(struct typec_altmode *adev, u32 vdo)
 156 {
 157         struct typec_altmode *pdev = &to_altmode(adev)->partner->adev;
 158
 159         if (pdev->ops && pdev->ops->attention)
 160                 pdev->ops->attention(pdev, vdo);
 161 }
 162 EXPORT_SYMBOL_GPL(typec_altmode_attention);
 163
 164 /**
 165  * typec_altmode_vdm - Send Vendor Defined Messages (VDM) to the partner
 166  * @adev: Alternate mode handle
 167  * @header: VDM Header
 168  * @vdo: Array of Vendor Defined Data Objects
 169  * @count: Number of Data Objects
 170  *
 171  * The alternate mode drivers use this function for SVID specific communication
 172  * with the partner. The port drivers use it to deliver the Structured VDMs
 173  * received from the partners to the alternate mode drivers.
 174  */
 175 int typec_altmode_vdm(struct typec_altmode *adev,
 176                       const u32 header, const u32 *vdo, int count)
 177 {
 178         struct typec_altmode *pdev;
 179         struct altmode *altmode;
 180
 181         if (!adev)
 182                 return 0;
 183
 184         altmode = to_altmode(adev);
 185
 186         if (!altmode->partner)
 187                 return -ENODEV;
 188
 189         pdev = &altmode->partner->adev;
 190
 191         if (!pdev->ops || !pdev->ops->vdm)
 192                 return -EOPNOTSUPP;
 193
 194         return pdev->ops->vdm(pdev, header, vdo, count);
 195 }
 196 EXPORT_SYMBOL_GPL(typec_altmode_vdm);
 197
 198 const struct typec_altmode *
 199 typec_altmode_get_partner(struct typec_altmode *adev)
 200 {
 201         if (!adev || !to_altmode(adev)->partner)
 202                 return NULL;
 203
 204         return &to_altmode(adev)->partner->adev;
 205 }
 206 EXPORT_SYMBOL_GPL(typec_altmode_get_partner);
 207
 208 /* -------------------------------------------------------------------------- */
 209 /* API for the alternate mode drivers */
 210
 211 /**
 212  * typec_altmode_get_plug - Find cable plug alternate mode
 213  * @adev: Handle to partner alternate mode
 214  * @index: Cable plug index
 215  *
 216  * Increment reference count for cable plug alternate mode device. Returns
 217  * handle to the cable plug alternate mode, or NULL if none is found.
 218  */
 219 struct typec_altmode *typec_altmode_get_plug(struct typec_altmode *adev,
 220                                              enum typec_plug_index index)
 221 {
 222         struct altmode *port = to_altmode(adev)->partner;
 223
 224         if (port->plug[index]) {
 225                 get_device(&port->plug[index]->adev.dev);
 226                 return &port->plug[index]->adev;
 227         }
 228
 229         return NULL;
 230 }
 231 EXPORT_SYMBOL_GPL(typec_altmode_get_plug);
 232
 233 /**
 234  * typec_altmode_put_plug - Decrement cable plug alternate mode reference count
 235  * @plug: Handle to the cable plug alternate mode
 236  */
 237 void typec_altmode_put_plug(struct typec_altmode *plug)
 238 {
 239         if (plug)
 240                 put_device(&plug->dev);
 241 }
 242 EXPORT_SYMBOL_GPL(typec_altmode_put_plug);
 243
 244 int __typec_altmode_register_driver(struct typec_altmode_driver *drv,
 245                                     struct module *module)
 246 {
 247         if (!drv->probe)
 248                 return -EINVAL;
 249
 250         drv->driver.owner = module;
 251         drv->driver.bus = &typec_bus;
 252
 253         return driver_register(&drv->driver);
 254 }
 255 EXPORT_SYMBOL_GPL(__typec_altmode_register_driver);
 256
 257 void typec_altmode_unregister_driver(struct typec_altmode_driver *drv)
 258 {
 259         driver_unregister(&drv->driver);
 260 }
 261 EXPORT_SYMBOL_GPL(typec_altmode_unregister_driver);
 262
 263 /* -------------------------------------------------------------------------- */
 264 /* API for the port drivers */
 265
 266 /**
 267  * typec_match_altmode - Match SVID and mode to an array of alternate modes
 268  * @altmodes: Array of alternate modes
 269  * @n: Number of elements in the array, or -1 for NULL terminated arrays
 270  * @svid: Standard or Vendor ID to match with
 271  * @mode: Mode to match with
 272  *
 273  * Return pointer to an alternate mode with SVID matching @svid, or NULL when no
 274  * match is found.
 275  */
 276 struct typec_altmode *typec_match_altmode(struct typec_altmode **altmodes,
 277                                           size_t n, u16 svid, u8 mode)
 278 {
 279         int i;
 280
 281         for (i = 0; i < n; i++) {
 282                 if (!altmodes[i])
 283                         break;
 284                 if (altmodes[i]->svid == svid && altmodes[i]->mode == mode)
 285                         return altmodes[i];
 286         }
 287
 288         return NULL;
 289 }
 290 EXPORT_SYMBOL_GPL(typec_match_altmode);
 291
 292 /* -------------------------------------------------------------------------- */
 293
 294 static ssize_t
 295 description_show(struct device *dev, struct device_attribute *attr, char *buf)
 296 {
 297         struct typec_altmode *alt = to_typec_altmode(dev);
 298
 299         return sprintf(buf, "%s\n", alt->desc ? alt->desc : "");
 300 }
 301 static DEVICE_ATTR_RO(description);
 302
 303 static struct attribute *typec_attrs[] = {
 304         &dev_attr_description.attr,
 305         NULL
 306 };
 307 ATTRIBUTE_GROUPS(typec);
 308
 309 static int typec_match(struct device *dev, struct device_driver *driver)
 310 {
 311         struct typec_altmode_driver *drv = to_altmode_driver(driver);
 312         struct typec_altmode *altmode = to_typec_altmode(dev);
 313         const struct typec_device_id *id;
 314
 315         for (id = drv->id_table; id->svid; id++)
 316                 if (id->svid == altmode->svid &&
 317                     (id->mode == TYPEC_ANY_MODE || id->mode == altmode->mode))
 318                         return 1;
 319         return 0;
 320 }
 321
 322 static int typec_uevent(struct device *dev, struct kobj_uevent_env *env)
 323 {
 324         struct typec_altmode *altmode = to_typec_altmode(dev);
 325
 326         if (add_uevent_var(env, "SVID=%04X", altmode->svid))
 327                 return -ENOMEM;
 328
 329         if (add_uevent_var(env, "MODE=%u", altmode->mode))
 330                 return -ENOMEM;
 331
 332         return add_uevent_var(env, "MODALIAS=typec:id%04Xm%02X",
 333                               altmode->svid, altmode->mode);
 334 }
 335
 336 static int typec_altmode_create_links(struct altmode *alt)
 337 {
 338         struct device *port_dev = &alt->partner->adev.dev;
 339         struct device *dev = &alt->adev.dev;
 340         int err;
 341
 342         err = sysfs_create_link(&dev->kobj, &port_dev->kobj, "port");
 343         if (err)
 344                 return err;
 345
 346         err = sysfs_create_link(&port_dev->kobj, &dev->kobj, "partner");
 347         if (err)
 348                 sysfs_remove_link(&dev->kobj, "port");
 349
 350         return err;
 351 }
 352
 353 static void typec_altmode_remove_links(struct altmode *alt)
 354 {
 355         sysfs_remove_link(&alt->partner->adev.dev.kobj, "partner");
 356         sysfs_remove_link(&alt->adev.dev.kobj, "port");
 357 }
 358
 359 static int typec_probe(struct device *dev)
 360 {
 361         struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
 362         struct typec_altmode *adev = to_typec_altmode(dev);
 363         struct altmode *altmode = to_altmode(adev);
 364         int ret;
 365
 366         /* Fail if the port does not support the alternate mode */
 367         if (!altmode->partner)
 368                 return -ENODEV;
 369
 370         ret = typec_altmode_create_links(altmode);
 371         if (ret) {
 372                 dev_warn(dev, "failed to create symlinks\n");
 373                 return ret;
 374         }
 375
 376         ret = drv->probe(adev);
 377         if (ret)
 378                 typec_altmode_remove_links(altmode);
 379
 380         return ret;
 381 }
 382
 383 static int typec_remove(struct device *dev)
 384 {
 385         struct typec_altmode_driver *drv = to_altmode_driver(dev->driver);
 386         struct typec_altmode *adev = to_typec_altmode(dev);
 387         struct altmode *altmode = to_altmode(adev);
 388
 389         typec_altmode_remove_links(altmode);
 390
 391         if (drv->remove)
 392                 drv->remove(to_typec_altmode(dev));
 393
 394         if (adev->active) {
 395                 WARN_ON(typec_altmode_set_state(adev, TYPEC_STATE_SAFE, NULL));
 396                 typec_altmode_update_active(adev, false);
 397         }
 398
 399         adev->desc = NULL;
 400         adev->ops = NULL;
 401
 402         return 0;
 403 }
 404
 405 struct bus_type typec_bus = {
 406         .name = "typec",
 407         .dev_groups = typec_groups,
 408         .match = typec_match,
 409         .uevent = typec_uevent,
 410         .probe = typec_probe,
 411         .remove = typec_remove,
 412 };