1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * Surface System Aggregator Module (SSAM) bus and client-device subsystem. 4 * 5 * Main interface for the surface-aggregator bus, surface-aggregator client 6 * devices, and respective drivers building on top of the SSAM controller. 7 * Provides support for non-platform/non-ACPI SSAM clients via dedicated 8 * subsystem. 9 * 10 * Copyright (C) 2019-2021 Maximilian Luz <luzmaximilian@gmail.com> 11 */ 12 13 #ifndef _LINUX_SURFACE_AGGREGATOR_DEVICE_H 14 #define _LINUX_SURFACE_AGGREGATOR_DEVICE_H 15 16 #include <linux/device.h> 17 #include <linux/mod_devicetable.h> 18 #include <linux/property.h> 19 #include <linux/types.h> 20 21 #include <linux/surface_aggregator/controller.h> 22 23 24 /* -- Surface System Aggregator Module bus. --------------------------------- */ 25 26 /** 27 * enum ssam_device_domain - SAM device domain. 28 * @SSAM_DOMAIN_VIRTUAL: Virtual device. 29 * @SSAM_DOMAIN_SERIALHUB: Physical device connected via Surface Serial Hub. 30 */ 31 enum ssam_device_domain { 32 SSAM_DOMAIN_VIRTUAL = 0x00, 33 SSAM_DOMAIN_SERIALHUB = 0x01, 34 }; 35 36 /** 37 * enum ssam_virtual_tc - Target categories for the virtual SAM domain. 38 * @SSAM_VIRTUAL_TC_HUB: Device hub category. 39 */ 40 enum ssam_virtual_tc { 41 SSAM_VIRTUAL_TC_HUB = 0x00, 42 }; 43 44 /** 45 * struct ssam_device_uid - Unique identifier for SSAM device. 46 * @domain: Domain of the device. 47 * @category: Target category of the device. 48 * @target: Target ID of the device. 49 * @instance: Instance ID of the device. 50 * @function: Sub-function of the device. This field can be used to split a 51 * single SAM device into multiple virtual subdevices to separate 52 * different functionality of that device and allow one driver per 53 * such functionality. 54 */ 55 struct ssam_device_uid { 56 u8 domain; 57 u8 category; 58 u8 target; 59 u8 instance; 60 u8 function; 61 }; 62 63 /* 64 * Special values for device matching. 65 * 66 * These values are intended to be used with SSAM_DEVICE(), SSAM_VDEV(), and 67 * SSAM_SDEV() exclusively. Specifically, they are used to initialize the 68 * match_flags member of the device ID structure. Do not use them directly 69 * with struct ssam_device_id or struct ssam_device_uid. 70 */ 71 #define SSAM_SSH_TID_ANY 0xffff 72 #define SSAM_SSH_IID_ANY 0xffff 73 #define SSAM_SSH_FUN_ANY 0xffff 74 75 /** 76 * SSAM_DEVICE() - Initialize a &struct ssam_device_id with the given 77 * parameters. 78 * @d: Domain of the device. 79 * @cat: Target category of the device. 80 * @tid: Target ID of the device. 81 * @iid: Instance ID of the device. 82 * @fun: Sub-function of the device. 83 * 84 * Initializes a &struct ssam_device_id with the given parameters. See &struct 85 * ssam_device_uid for details regarding the parameters. The special values 86 * %SSAM_SSH_TID_ANY, %SSAM_SSH_IID_ANY, and %SSAM_SSH_FUN_ANY can be used to specify that 87 * matching should ignore target ID, instance ID, and/or sub-function, 88 * respectively. This macro initializes the ``match_flags`` field based on the 89 * given parameters. 90 * 91 * Note: The parameters @d and @cat must be valid &u8 values, the parameters 92 * @tid, @iid, and @fun must be either valid &u8 values or %SSAM_SSH_TID_ANY, 93 * %SSAM_SSH_IID_ANY, or %SSAM_SSH_FUN_ANY, respectively. Other non-&u8 values are not 94 * allowed. 95 */ 96 #define SSAM_DEVICE(d, cat, tid, iid, fun) \ 97 .match_flags = (((tid) != SSAM_SSH_TID_ANY) ? SSAM_MATCH_TARGET : 0) \ 98 | (((iid) != SSAM_SSH_IID_ANY) ? SSAM_MATCH_INSTANCE : 0) \ 99 | (((fun) != SSAM_SSH_FUN_ANY) ? SSAM_MATCH_FUNCTION : 0), \ 100 .domain = d, \ 101 .category = cat, \ 102 .target = __builtin_choose_expr((tid) != SSAM_SSH_TID_ANY, (tid), 0), \ 103 .instance = __builtin_choose_expr((iid) != SSAM_SSH_IID_ANY, (iid), 0), \ 104 .function = __builtin_choose_expr((fun) != SSAM_SSH_FUN_ANY, (fun), 0) 105 106 /** 107 * SSAM_VDEV() - Initialize a &struct ssam_device_id as virtual device with 108 * the given parameters. 109 * @cat: Target category of the device. 110 * @tid: Target ID of the device. 111 * @iid: Instance ID of the device. 112 * @fun: Sub-function of the device. 113 * 114 * Initializes a &struct ssam_device_id with the given parameters in the 115 * virtual domain. See &struct ssam_device_uid for details regarding the 116 * parameters. The special values %SSAM_SSH_TID_ANY, %SSAM_SSH_IID_ANY, and 117 * %SSAM_SSH_FUN_ANY can be used to specify that matching should ignore target ID, 118 * instance ID, and/or sub-function, respectively. This macro initializes the 119 * ``match_flags`` field based on the given parameters. 120 * 121 * Note: The parameter @cat must be a valid &u8 value, the parameters @tid, 122 * @iid, and @fun must be either valid &u8 values or %SSAM_SSH_TID_ANY, 123 * %SSAM_SSH_IID_ANY, or %SSAM_SSH_FUN_ANY, respectively. Other non-&u8 values are not 124 * allowed. 125 */ 126 #define SSAM_VDEV(cat, tid, iid, fun) \ 127 SSAM_DEVICE(SSAM_DOMAIN_VIRTUAL, SSAM_VIRTUAL_TC_##cat, SSAM_SSH_TID_##tid, iid, fun) 128 129 /** 130 * SSAM_SDEV() - Initialize a &struct ssam_device_id as physical SSH device 131 * with the given parameters. 132 * @cat: Target category of the device. 133 * @tid: Target ID of the device. 134 * @iid: Instance ID of the device. 135 * @fun: Sub-function of the device. 136 * 137 * Initializes a &struct ssam_device_id with the given parameters in the SSH 138 * domain. See &struct ssam_device_uid for details regarding the parameters. 139 * The special values %SSAM_SSH_TID_ANY, %SSAM_SSH_IID_ANY, and 140 * %SSAM_SSH_FUN_ANY can be used to specify that matching should ignore target 141 * ID, instance ID, and/or sub-function, respectively. This macro initializes 142 * the ``match_flags`` field based on the given parameters. 143 * 144 * Note: The parameter @cat must be a valid &u8 value, the parameters @tid, 145 * @iid, and @fun must be either valid &u8 values or %SSAM_SSH_TID_ANY, 146 * %SSAM_SSH_IID_ANY, or %SSAM_SSH_FUN_ANY, respectively. Other non-&u8 values 147 * are not allowed. 148 */ 149 #define SSAM_SDEV(cat, tid, iid, fun) \ 150 SSAM_DEVICE(SSAM_DOMAIN_SERIALHUB, SSAM_SSH_TC_##cat, SSAM_SSH_TID_##tid, iid, fun) 151 152 /* 153 * enum ssam_device_flags - Flags for SSAM client devices. 154 * @SSAM_DEVICE_HOT_REMOVED_BIT: 155 * The device has been hot-removed. Further communication with it may time 156 * out and should be avoided. 157 */ 158 enum ssam_device_flags { 159 SSAM_DEVICE_HOT_REMOVED_BIT = 0, 160 }; 161 162 /** 163 * struct ssam_device - SSAM client device. 164 * @dev: Driver model representation of the device. 165 * @ctrl: SSAM controller managing this device. 166 * @uid: UID identifying the device. 167 * @flags: Device state flags, see &enum ssam_device_flags. 168 */ 169 struct ssam_device { 170 struct device dev; 171 struct ssam_controller *ctrl; 172 173 struct ssam_device_uid uid; 174 175 unsigned long flags; 176 }; 177 178 /** 179 * struct ssam_device_driver - SSAM client device driver. 180 * @driver: Base driver model structure. 181 * @match_table: Match table specifying which devices the driver should bind to. 182 * @probe: Called when the driver is being bound to a device. 183 * @remove: Called when the driver is being unbound from the device. 184 */ 185 struct ssam_device_driver { 186 struct device_driver driver; 187 188 const struct ssam_device_id *match_table; 189 190 int (*probe)(struct ssam_device *sdev); 191 void (*remove)(struct ssam_device *sdev); 192 }; 193 194 #ifdef CONFIG_SURFACE_AGGREGATOR_BUS 195 196 extern struct bus_type ssam_bus_type; 197 extern const struct device_type ssam_device_type; 198 199 /** 200 * is_ssam_device() - Check if the given device is a SSAM client device. 201 * @d: The device to test the type of. 202 * 203 * Return: Returns %true if the specified device is of type &struct 204 * ssam_device, i.e. the device type points to %ssam_device_type, and %false 205 * otherwise. 206 */ 207 static inline bool is_ssam_device(struct device *d) 208 { 209 return d->type == &ssam_device_type; 210 } 211 212 #else /* CONFIG_SURFACE_AGGREGATOR_BUS */ 213 214 static inline bool is_ssam_device(struct device *d) 215 { 216 return false; 217 } 218 219 #endif /* CONFIG_SURFACE_AGGREGATOR_BUS */ 220 221 /** 222 * to_ssam_device() - Casts the given device to a SSAM client device. 223 * @d: The device to cast. 224 * 225 * Casts the given &struct device to a &struct ssam_device. The caller has to 226 * ensure that the given device is actually enclosed in a &struct ssam_device, 227 * e.g. by calling is_ssam_device(). 228 * 229 * Return: Returns a pointer to the &struct ssam_device wrapping the given 230 * device @d. 231 */ 232 #define to_ssam_device(d) container_of_const(d, struct ssam_device, dev) 233 234 /** 235 * to_ssam_device_driver() - Casts the given device driver to a SSAM client 236 * device driver. 237 * @d: The driver to cast. 238 * 239 * Casts the given &struct device_driver to a &struct ssam_device_driver. The 240 * caller has to ensure that the given driver is actually enclosed in a 241 * &struct ssam_device_driver. 242 * 243 * Return: Returns the pointer to the &struct ssam_device_driver wrapping the 244 * given device driver @d. 245 */ 246 #define to_ssam_device_driver(d) container_of_const(d, struct ssam_device_driver, driver) 247 248 const struct ssam_device_id *ssam_device_id_match(const struct ssam_device_id *table, 249 const struct ssam_device_uid uid); 250 251 const struct ssam_device_id *ssam_device_get_match(const struct ssam_device *dev); 252 253 const void *ssam_device_get_match_data(const struct ssam_device *dev); 254 255 struct ssam_device *ssam_device_alloc(struct ssam_controller *ctrl, 256 struct ssam_device_uid uid); 257 258 int ssam_device_add(struct ssam_device *sdev); 259 void ssam_device_remove(struct ssam_device *sdev); 260 261 /** 262 * ssam_device_mark_hot_removed() - Mark the given device as hot-removed. 263 * @sdev: The device to mark as hot-removed. 264 * 265 * Mark the device as having been hot-removed. This signals drivers using the 266 * device that communication with the device should be avoided and may lead to 267 * timeouts. 268 */ 269 static inline void ssam_device_mark_hot_removed(struct ssam_device *sdev) 270 { 271 dev_dbg(&sdev->dev, "marking device as hot-removed\n"); 272 set_bit(SSAM_DEVICE_HOT_REMOVED_BIT, &sdev->flags); 273 } 274 275 /** 276 * ssam_device_is_hot_removed() - Check if the given device has been 277 * hot-removed. 278 * @sdev: The device to check. 279 * 280 * Checks if the given device has been marked as hot-removed. See 281 * ssam_device_mark_hot_removed() for more details. 282 * 283 * Return: Returns ``true`` if the device has been marked as hot-removed. 284 */ 285 static inline bool ssam_device_is_hot_removed(struct ssam_device *sdev) 286 { 287 return test_bit(SSAM_DEVICE_HOT_REMOVED_BIT, &sdev->flags); 288 } 289 290 /** 291 * ssam_device_get() - Increment reference count of SSAM client device. 292 * @sdev: The device to increment the reference count of. 293 * 294 * Increments the reference count of the given SSAM client device by 295 * incrementing the reference count of the enclosed &struct device via 296 * get_device(). 297 * 298 * See ssam_device_put() for the counter-part of this function. 299 * 300 * Return: Returns the device provided as input. 301 */ 302 static inline struct ssam_device *ssam_device_get(struct ssam_device *sdev) 303 { 304 return sdev ? to_ssam_device(get_device(&sdev->dev)) : NULL; 305 } 306 307 /** 308 * ssam_device_put() - Decrement reference count of SSAM client device. 309 * @sdev: The device to decrement the reference count of. 310 * 311 * Decrements the reference count of the given SSAM client device by 312 * decrementing the reference count of the enclosed &struct device via 313 * put_device(). 314 * 315 * See ssam_device_get() for the counter-part of this function. 316 */ 317 static inline void ssam_device_put(struct ssam_device *sdev) 318 { 319 if (sdev) 320 put_device(&sdev->dev); 321 } 322 323 /** 324 * ssam_device_get_drvdata() - Get driver-data of SSAM client device. 325 * @sdev: The device to get the driver-data from. 326 * 327 * Return: Returns the driver-data of the given device, previously set via 328 * ssam_device_set_drvdata(). 329 */ 330 static inline void *ssam_device_get_drvdata(struct ssam_device *sdev) 331 { 332 return dev_get_drvdata(&sdev->dev); 333 } 334 335 /** 336 * ssam_device_set_drvdata() - Set driver-data of SSAM client device. 337 * @sdev: The device to set the driver-data of. 338 * @data: The data to set the device's driver-data pointer to. 339 */ 340 static inline void ssam_device_set_drvdata(struct ssam_device *sdev, void *data) 341 { 342 dev_set_drvdata(&sdev->dev, data); 343 } 344 345 int __ssam_device_driver_register(struct ssam_device_driver *d, struct module *o); 346 void ssam_device_driver_unregister(struct ssam_device_driver *d); 347 348 /** 349 * ssam_device_driver_register() - Register a SSAM client device driver. 350 * @drv: The driver to register. 351 */ 352 #define ssam_device_driver_register(drv) \ 353 __ssam_device_driver_register(drv, THIS_MODULE) 354 355 /** 356 * module_ssam_device_driver() - Helper macro for SSAM device driver 357 * registration. 358 * @drv: The driver managed by this module. 359 * 360 * Helper macro to register a SSAM device driver via module_init() and 361 * module_exit(). This macro may only be used once per module and replaces the 362 * aforementioned definitions. 363 */ 364 #define module_ssam_device_driver(drv) \ 365 module_driver(drv, ssam_device_driver_register, \ 366 ssam_device_driver_unregister) 367 368 369 /* -- Helpers for controller and hub devices. ------------------------------- */ 370 371 #ifdef CONFIG_SURFACE_AGGREGATOR_BUS 372 373 int __ssam_register_clients(struct device *parent, struct ssam_controller *ctrl, 374 struct fwnode_handle *node); 375 void ssam_remove_clients(struct device *dev); 376 377 #else /* CONFIG_SURFACE_AGGREGATOR_BUS */ 378 379 static inline int __ssam_register_clients(struct device *parent, struct ssam_controller *ctrl, 380 struct fwnode_handle *node) 381 { 382 return 0; 383 } 384 385 static inline void ssam_remove_clients(struct device *dev) {} 386 387 #endif /* CONFIG_SURFACE_AGGREGATOR_BUS */ 388 389 /** 390 * ssam_register_clients() - Register all client devices defined under the 391 * given parent device. 392 * @dev: The parent device under which clients should be registered. 393 * @ctrl: The controller with which client should be registered. 394 * 395 * Register all clients that have via firmware nodes been defined as children 396 * of the given (parent) device. The respective child firmware nodes will be 397 * associated with the correspondingly created child devices. 398 * 399 * The given controller will be used to instantiate the new devices. See 400 * ssam_device_add() for details. 401 * 402 * Return: Returns zero on success, nonzero on failure. 403 */ 404 static inline int ssam_register_clients(struct device *dev, struct ssam_controller *ctrl) 405 { 406 return __ssam_register_clients(dev, ctrl, dev_fwnode(dev)); 407 } 408 409 /** 410 * ssam_device_register_clients() - Register all client devices defined under 411 * the given SSAM parent device. 412 * @sdev: The parent device under which clients should be registered. 413 * 414 * Register all clients that have via firmware nodes been defined as children 415 * of the given (parent) device. The respective child firmware nodes will be 416 * associated with the correspondingly created child devices. 417 * 418 * The controller used by the parent device will be used to instantiate the new 419 * devices. See ssam_device_add() for details. 420 * 421 * Return: Returns zero on success, nonzero on failure. 422 */ 423 static inline int ssam_device_register_clients(struct ssam_device *sdev) 424 { 425 return ssam_register_clients(&sdev->dev, sdev->ctrl); 426 } 427 428 429 /* -- Helpers for client-device requests. ----------------------------------- */ 430 431 /** 432 * SSAM_DEFINE_SYNC_REQUEST_CL_N() - Define synchronous client-device SAM 433 * request function with neither argument nor return value. 434 * @name: Name of the generated function. 435 * @spec: Specification (&struct ssam_request_spec_md) defining the request. 436 * 437 * Defines a function executing the synchronous SAM request specified by 438 * @spec, with the request having neither argument nor return value. Device 439 * specifying parameters are not hard-coded, but instead are provided via the 440 * client device, specifically its UID, supplied when calling this function. 441 * The generated function takes care of setting up the request struct, buffer 442 * allocation, as well as execution of the request itself, returning once the 443 * request has been fully completed. The required transport buffer will be 444 * allocated on the stack. 445 * 446 * The generated function is defined as ``static int name(struct ssam_device 447 * *sdev)``, returning the status of the request, which is zero on success and 448 * negative on failure. The ``sdev`` parameter specifies both the target 449 * device of the request and by association the controller via which the 450 * request is sent. 451 * 452 * Refer to ssam_request_do_sync_onstack() for more details on the behavior of 453 * the generated function. 454 */ 455 #define SSAM_DEFINE_SYNC_REQUEST_CL_N(name, spec...) \ 456 SSAM_DEFINE_SYNC_REQUEST_MD_N(__raw_##name, spec) \ 457 static int name(struct ssam_device *sdev) \ 458 { \ 459 return __raw_##name(sdev->ctrl, sdev->uid.target, \ 460 sdev->uid.instance); \ 461 } 462 463 /** 464 * SSAM_DEFINE_SYNC_REQUEST_CL_W() - Define synchronous client-device SAM 465 * request function with argument. 466 * @name: Name of the generated function. 467 * @atype: Type of the request's argument. 468 * @spec: Specification (&struct ssam_request_spec_md) defining the request. 469 * 470 * Defines a function executing the synchronous SAM request specified by 471 * @spec, with the request taking an argument of type @atype and having no 472 * return value. Device specifying parameters are not hard-coded, but instead 473 * are provided via the client device, specifically its UID, supplied when 474 * calling this function. The generated function takes care of setting up the 475 * request struct, buffer allocation, as well as execution of the request 476 * itself, returning once the request has been fully completed. The required 477 * transport buffer will be allocated on the stack. 478 * 479 * The generated function is defined as ``static int name(struct ssam_device 480 * *sdev, const atype *arg)``, returning the status of the request, which is 481 * zero on success and negative on failure. The ``sdev`` parameter specifies 482 * both the target device of the request and by association the controller via 483 * which the request is sent. The request's argument is specified via the 484 * ``arg`` pointer. 485 * 486 * Refer to ssam_request_do_sync_onstack() for more details on the behavior of 487 * the generated function. 488 */ 489 #define SSAM_DEFINE_SYNC_REQUEST_CL_W(name, atype, spec...) \ 490 SSAM_DEFINE_SYNC_REQUEST_MD_W(__raw_##name, atype, spec) \ 491 static int name(struct ssam_device *sdev, const atype *arg) \ 492 { \ 493 return __raw_##name(sdev->ctrl, sdev->uid.target, \ 494 sdev->uid.instance, arg); \ 495 } 496 497 /** 498 * SSAM_DEFINE_SYNC_REQUEST_CL_R() - Define synchronous client-device SAM 499 * request function with return value. 500 * @name: Name of the generated function. 501 * @rtype: Type of the request's return value. 502 * @spec: Specification (&struct ssam_request_spec_md) defining the request. 503 * 504 * Defines a function executing the synchronous SAM request specified by 505 * @spec, with the request taking no argument but having a return value of 506 * type @rtype. Device specifying parameters are not hard-coded, but instead 507 * are provided via the client device, specifically its UID, supplied when 508 * calling this function. The generated function takes care of setting up the 509 * request struct, buffer allocation, as well as execution of the request 510 * itself, returning once the request has been fully completed. The required 511 * transport buffer will be allocated on the stack. 512 * 513 * The generated function is defined as ``static int name(struct ssam_device 514 * *sdev, rtype *ret)``, returning the status of the request, which is zero on 515 * success and negative on failure. The ``sdev`` parameter specifies both the 516 * target device of the request and by association the controller via which 517 * the request is sent. The request's return value is written to the memory 518 * pointed to by the ``ret`` parameter. 519 * 520 * Refer to ssam_request_do_sync_onstack() for more details on the behavior of 521 * the generated function. 522 */ 523 #define SSAM_DEFINE_SYNC_REQUEST_CL_R(name, rtype, spec...) \ 524 SSAM_DEFINE_SYNC_REQUEST_MD_R(__raw_##name, rtype, spec) \ 525 static int name(struct ssam_device *sdev, rtype *ret) \ 526 { \ 527 return __raw_##name(sdev->ctrl, sdev->uid.target, \ 528 sdev->uid.instance, ret); \ 529 } 530 531 /** 532 * SSAM_DEFINE_SYNC_REQUEST_CL_WR() - Define synchronous client-device SAM 533 * request function with argument and return value. 534 * @name: Name of the generated function. 535 * @atype: Type of the request's argument. 536 * @rtype: Type of the request's return value. 537 * @spec: Specification (&struct ssam_request_spec_md) defining the request. 538 * 539 * Defines a function executing the synchronous SAM request specified by @spec, 540 * with the request taking an argument of type @atype and having a return value 541 * of type @rtype. Device specifying parameters are not hard-coded, but instead 542 * are provided via the client device, specifically its UID, supplied when 543 * calling this function. The generated function takes care of setting up the 544 * request struct, buffer allocation, as well as execution of the request 545 * itself, returning once the request has been fully completed. The required 546 * transport buffer will be allocated on the stack. 547 * 548 * The generated function is defined as ``static int name(struct ssam_device 549 * *sdev, const atype *arg, rtype *ret)``, returning the status of the request, 550 * which is zero on success and negative on failure. The ``sdev`` parameter 551 * specifies both the target device of the request and by association the 552 * controller via which the request is sent. The request's argument is 553 * specified via the ``arg`` pointer. The request's return value is written to 554 * the memory pointed to by the ``ret`` parameter. 555 * 556 * Refer to ssam_request_do_sync_onstack() for more details on the behavior of 557 * the generated function. 558 */ 559 #define SSAM_DEFINE_SYNC_REQUEST_CL_WR(name, atype, rtype, spec...) \ 560 SSAM_DEFINE_SYNC_REQUEST_MD_WR(__raw_##name, atype, rtype, spec) \ 561 static int name(struct ssam_device *sdev, const atype *arg, rtype *ret) \ 562 { \ 563 return __raw_##name(sdev->ctrl, sdev->uid.target, \ 564 sdev->uid.instance, arg, ret); \ 565 } 566 567 568 /* -- Helpers for client-device notifiers. ---------------------------------- */ 569 570 /** 571 * ssam_device_notifier_register() - Register an event notifier for the 572 * specified client device. 573 * @sdev: The device the notifier should be registered on. 574 * @n: The event notifier to register. 575 * 576 * Register an event notifier. Increment the usage counter of the associated 577 * SAM event if the notifier is not marked as an observer. If the event is not 578 * marked as an observer and is currently not enabled, it will be enabled 579 * during this call. If the notifier is marked as an observer, no attempt will 580 * be made at enabling any event and no reference count will be modified. 581 * 582 * Notifiers marked as observers do not need to be associated with one specific 583 * event, i.e. as long as no event matching is performed, only the event target 584 * category needs to be set. 585 * 586 * Return: Returns zero on success, %-ENOSPC if there have already been 587 * %INT_MAX notifiers for the event ID/type associated with the notifier block 588 * registered, %-ENOMEM if the corresponding event entry could not be 589 * allocated, %-ENODEV if the device is marked as hot-removed. If this is the 590 * first time that a notifier block is registered for the specific associated 591 * event, returns the status of the event-enable EC-command. 592 */ 593 static inline int ssam_device_notifier_register(struct ssam_device *sdev, 594 struct ssam_event_notifier *n) 595 { 596 /* 597 * Note that this check does not provide any guarantees whatsoever as 598 * hot-removal could happen at any point and we can't protect against 599 * it. Nevertheless, if we can detect hot-removal, bail early to avoid 600 * communication timeouts. 601 */ 602 if (ssam_device_is_hot_removed(sdev)) 603 return -ENODEV; 604 605 return ssam_notifier_register(sdev->ctrl, n); 606 } 607 608 /** 609 * ssam_device_notifier_unregister() - Unregister an event notifier for the 610 * specified client device. 611 * @sdev: The device the notifier has been registered on. 612 * @n: The event notifier to unregister. 613 * 614 * Unregister an event notifier. Decrement the usage counter of the associated 615 * SAM event if the notifier is not marked as an observer. If the usage counter 616 * reaches zero, the event will be disabled. 617 * 618 * In case the device has been marked as hot-removed, the event will not be 619 * disabled on the EC, as in those cases any attempt at doing so may time out. 620 * 621 * Return: Returns zero on success, %-ENOENT if the given notifier block has 622 * not been registered on the controller. If the given notifier block was the 623 * last one associated with its specific event, returns the status of the 624 * event-disable EC-command. 625 */ 626 static inline int ssam_device_notifier_unregister(struct ssam_device *sdev, 627 struct ssam_event_notifier *n) 628 { 629 return __ssam_notifier_unregister(sdev->ctrl, n, 630 !ssam_device_is_hot_removed(sdev)); 631 } 632 633 #endif /* _LINUX_SURFACE_AGGREGATOR_DEVICE_H */ 634