1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2016-2017 Linaro Ltd., Rob Herring <robh@kernel.org>
4 *
5 * Based on drivers/spmi/spmi.c:
6 * Copyright (c) 2012-2015, The Linux Foundation. All rights reserved.
7 */
8
9#include <linux/acpi.h>
10#include <linux/errno.h>
11#include <linux/idr.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/of.h>
15#include <linux/of_device.h>
16#include <linux/pm_domain.h>
17#include <linux/pm_runtime.h>
18#include <linux/property.h>
19#include <linux/sched.h>
20#include <linux/serdev.h>
21#include <linux/slab.h>
22
23#include <linux/platform_data/x86/apple.h>
24
25static bool is_registered;
26static DEFINE_IDA(ctrl_ida);
27
28static ssize_t modalias_show(struct device *dev,
29 struct device_attribute *attr, char *buf)
30{
31 int len;
32
33 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
34 if (len != -ENODEV)
35 return len;
36
37 return of_device_modalias(dev, str: buf, PAGE_SIZE);
38}
39static DEVICE_ATTR_RO(modalias);
40
41static struct attribute *serdev_device_attrs[] = {
42 &dev_attr_modalias.attr,
43 NULL,
44};
45ATTRIBUTE_GROUPS(serdev_device);
46
47static int serdev_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
48{
49 int rc;
50
51 /* TODO: platform modalias */
52
53 rc = acpi_device_uevent_modalias(dev, env);
54 if (rc != -ENODEV)
55 return rc;
56
57 return of_device_uevent_modalias(dev, env);
58}
59
60static void serdev_device_release(struct device *dev)
61{
62 struct serdev_device *serdev = to_serdev_device(d: dev);
63 kfree(objp: serdev);
64}
65
66static const struct device_type serdev_device_type = {
67 .groups = serdev_device_groups,
68 .uevent = serdev_device_uevent,
69 .release = serdev_device_release,
70};
71
72static bool is_serdev_device(const struct device *dev)
73{
74 return dev->type == &serdev_device_type;
75}
76
77static void serdev_ctrl_release(struct device *dev)
78{
79 struct serdev_controller *ctrl = to_serdev_controller(d: dev);
80 ida_simple_remove(&ctrl_ida, ctrl->nr);
81 kfree(objp: ctrl);
82}
83
84static const struct device_type serdev_ctrl_type = {
85 .release = serdev_ctrl_release,
86};
87
88static int serdev_device_match(struct device *dev, struct device_driver *drv)
89{
90 if (!is_serdev_device(dev))
91 return 0;
92
93 /* TODO: platform matching */
94 if (acpi_driver_match_device(dev, drv))
95 return 1;
96
97 return of_driver_match_device(dev, drv);
98}
99
100/**
101 * serdev_device_add() - add a device previously constructed via serdev_device_alloc()
102 * @serdev: serdev_device to be added
103 */
104int serdev_device_add(struct serdev_device *serdev)
105{
106 struct serdev_controller *ctrl = serdev->ctrl;
107 struct device *parent = serdev->dev.parent;
108 int err;
109
110 dev_set_name(dev: &serdev->dev, name: "%s-%d", dev_name(dev: parent), serdev->nr);
111
112 /* Only a single slave device is currently supported. */
113 if (ctrl->serdev) {
114 dev_err(&serdev->dev, "controller busy\n");
115 return -EBUSY;
116 }
117 ctrl->serdev = serdev;
118
119 err = device_add(dev: &serdev->dev);
120 if (err < 0) {
121 dev_err(&serdev->dev, "Can't add %s, status %pe\n",
122 dev_name(&serdev->dev), ERR_PTR(err));
123 goto err_clear_serdev;
124 }
125
126 dev_dbg(&serdev->dev, "device %s registered\n", dev_name(&serdev->dev));
127
128 return 0;
129
130err_clear_serdev:
131 ctrl->serdev = NULL;
132 return err;
133}
134EXPORT_SYMBOL_GPL(serdev_device_add);
135
136/**
137 * serdev_device_remove(): remove an serdev device
138 * @serdev: serdev_device to be removed
139 */
140void serdev_device_remove(struct serdev_device *serdev)
141{
142 struct serdev_controller *ctrl = serdev->ctrl;
143
144 device_unregister(dev: &serdev->dev);
145 ctrl->serdev = NULL;
146}
147EXPORT_SYMBOL_GPL(serdev_device_remove);
148
149int serdev_device_open(struct serdev_device *serdev)
150{
151 struct serdev_controller *ctrl = serdev->ctrl;
152 int ret;
153
154 if (!ctrl || !ctrl->ops->open)
155 return -EINVAL;
156
157 ret = ctrl->ops->open(ctrl);
158 if (ret)
159 return ret;
160
161 ret = pm_runtime_get_sync(dev: &ctrl->dev);
162 if (ret < 0) {
163 pm_runtime_put_noidle(dev: &ctrl->dev);
164 goto err_close;
165 }
166
167 return 0;
168
169err_close:
170 if (ctrl->ops->close)
171 ctrl->ops->close(ctrl);
172
173 return ret;
174}
175EXPORT_SYMBOL_GPL(serdev_device_open);
176
177void serdev_device_close(struct serdev_device *serdev)
178{
179 struct serdev_controller *ctrl = serdev->ctrl;
180
181 if (!ctrl || !ctrl->ops->close)
182 return;
183
184 pm_runtime_put(dev: &ctrl->dev);
185
186 ctrl->ops->close(ctrl);
187}
188EXPORT_SYMBOL_GPL(serdev_device_close);
189
190static void devm_serdev_device_close(void *serdev)
191{
192 serdev_device_close(serdev);
193}
194
195int devm_serdev_device_open(struct device *dev, struct serdev_device *serdev)
196{
197 int ret;
198
199 ret = serdev_device_open(serdev);
200 if (ret)
201 return ret;
202
203 return devm_add_action_or_reset(dev, devm_serdev_device_close, serdev);
204}
205EXPORT_SYMBOL_GPL(devm_serdev_device_open);
206
207void serdev_device_write_wakeup(struct serdev_device *serdev)
208{
209 complete(&serdev->write_comp);
210}
211EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
212
213/**
214 * serdev_device_write_buf() - write data asynchronously
215 * @serdev: serdev device
216 * @buf: data to be written
217 * @count: number of bytes to write
218 *
219 * Write data to the device asynchronously.
220 *
221 * Note that any accepted data has only been buffered by the controller; use
222 * serdev_device_wait_until_sent() to make sure the controller write buffer
223 * has actually been emptied.
224 *
225 * Return: The number of bytes written (less than count if not enough room in
226 * the write buffer), or a negative errno on errors.
227 */
228int serdev_device_write_buf(struct serdev_device *serdev,
229 const unsigned char *buf, size_t count)
230{
231 struct serdev_controller *ctrl = serdev->ctrl;
232
233 if (!ctrl || !ctrl->ops->write_buf)
234 return -EINVAL;
235
236 return ctrl->ops->write_buf(ctrl, buf, count);
237}
238EXPORT_SYMBOL_GPL(serdev_device_write_buf);
239
240/**
241 * serdev_device_write() - write data synchronously
242 * @serdev: serdev device
243 * @buf: data to be written
244 * @count: number of bytes to write
245 * @timeout: timeout in jiffies, or 0 to wait indefinitely
246 *
247 * Write data to the device synchronously by repeatedly calling
248 * serdev_device_write() until the controller has accepted all data (unless
249 * interrupted by a timeout or a signal).
250 *
251 * Note that any accepted data has only been buffered by the controller; use
252 * serdev_device_wait_until_sent() to make sure the controller write buffer
253 * has actually been emptied.
254 *
255 * Note that this function depends on serdev_device_write_wakeup() being
256 * called in the serdev driver write_wakeup() callback.
257 *
258 * Return: The number of bytes written (less than count if interrupted),
259 * -ETIMEDOUT or -ERESTARTSYS if interrupted before any bytes were written, or
260 * a negative errno on errors.
261 */
262int serdev_device_write(struct serdev_device *serdev,
263 const unsigned char *buf, size_t count,
264 long timeout)
265{
266 struct serdev_controller *ctrl = serdev->ctrl;
267 int written = 0;
268 int ret;
269
270 if (!ctrl || !ctrl->ops->write_buf || !serdev->ops->write_wakeup)
271 return -EINVAL;
272
273 if (timeout == 0)
274 timeout = MAX_SCHEDULE_TIMEOUT;
275
276 mutex_lock(&serdev->write_lock);
277 do {
278 reinit_completion(x: &serdev->write_comp);
279
280 ret = ctrl->ops->write_buf(ctrl, buf, count);
281 if (ret < 0)
282 break;
283
284 written += ret;
285 buf += ret;
286 count -= ret;
287
288 if (count == 0)
289 break;
290
291 timeout = wait_for_completion_interruptible_timeout(x: &serdev->write_comp,
292 timeout);
293 } while (timeout > 0);
294 mutex_unlock(lock: &serdev->write_lock);
295
296 if (ret < 0)
297 return ret;
298
299 if (timeout <= 0 && written == 0) {
300 if (timeout == -ERESTARTSYS)
301 return -ERESTARTSYS;
302 else
303 return -ETIMEDOUT;
304 }
305
306 return written;
307}
308EXPORT_SYMBOL_GPL(serdev_device_write);
309
310void serdev_device_write_flush(struct serdev_device *serdev)
311{
312 struct serdev_controller *ctrl = serdev->ctrl;
313
314 if (!ctrl || !ctrl->ops->write_flush)
315 return;
316
317 ctrl->ops->write_flush(ctrl);
318}
319EXPORT_SYMBOL_GPL(serdev_device_write_flush);
320
321int serdev_device_write_room(struct serdev_device *serdev)
322{
323 struct serdev_controller *ctrl = serdev->ctrl;
324
325 if (!ctrl || !ctrl->ops->write_room)
326 return 0;
327
328 return serdev->ctrl->ops->write_room(ctrl);
329}
330EXPORT_SYMBOL_GPL(serdev_device_write_room);
331
332unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
333{
334 struct serdev_controller *ctrl = serdev->ctrl;
335
336 if (!ctrl || !ctrl->ops->set_baudrate)
337 return 0;
338
339 return ctrl->ops->set_baudrate(ctrl, speed);
340
341}
342EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
343
344void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
345{
346 struct serdev_controller *ctrl = serdev->ctrl;
347
348 if (!ctrl || !ctrl->ops->set_flow_control)
349 return;
350
351 ctrl->ops->set_flow_control(ctrl, enable);
352}
353EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
354
355int serdev_device_set_parity(struct serdev_device *serdev,
356 enum serdev_parity parity)
357{
358 struct serdev_controller *ctrl = serdev->ctrl;
359
360 if (!ctrl || !ctrl->ops->set_parity)
361 return -EOPNOTSUPP;
362
363 return ctrl->ops->set_parity(ctrl, parity);
364}
365EXPORT_SYMBOL_GPL(serdev_device_set_parity);
366
367void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
368{
369 struct serdev_controller *ctrl = serdev->ctrl;
370
371 if (!ctrl || !ctrl->ops->wait_until_sent)
372 return;
373
374 ctrl->ops->wait_until_sent(ctrl, timeout);
375}
376EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
377
378int serdev_device_get_tiocm(struct serdev_device *serdev)
379{
380 struct serdev_controller *ctrl = serdev->ctrl;
381
382 if (!ctrl || !ctrl->ops->get_tiocm)
383 return -EOPNOTSUPP;
384
385 return ctrl->ops->get_tiocm(ctrl);
386}
387EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
388
389int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
390{
391 struct serdev_controller *ctrl = serdev->ctrl;
392
393 if (!ctrl || !ctrl->ops->set_tiocm)
394 return -EOPNOTSUPP;
395
396 return ctrl->ops->set_tiocm(ctrl, set, clear);
397}
398EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
399
400int serdev_device_break_ctl(struct serdev_device *serdev, int break_state)
401{
402 struct serdev_controller *ctrl = serdev->ctrl;
403
404 if (!ctrl || !ctrl->ops->break_ctl)
405 return -EOPNOTSUPP;
406
407 return ctrl->ops->break_ctl(ctrl, break_state);
408}
409EXPORT_SYMBOL_GPL(serdev_device_break_ctl);
410
411static int serdev_drv_probe(struct device *dev)
412{
413 const struct serdev_device_driver *sdrv = to_serdev_device_driver(d: dev->driver);
414 int ret;
415
416 ret = dev_pm_domain_attach(dev, power_on: true);
417 if (ret)
418 return ret;
419
420 ret = sdrv->probe(to_serdev_device(d: dev));
421 if (ret)
422 dev_pm_domain_detach(dev, power_off: true);
423
424 return ret;
425}
426
427static void serdev_drv_remove(struct device *dev)
428{
429 const struct serdev_device_driver *sdrv = to_serdev_device_driver(d: dev->driver);
430 if (sdrv->remove)
431 sdrv->remove(to_serdev_device(d: dev));
432
433 dev_pm_domain_detach(dev, power_off: true);
434}
435
436static struct bus_type serdev_bus_type = {
437 .name = "serial",
438 .match = serdev_device_match,
439 .probe = serdev_drv_probe,
440 .remove = serdev_drv_remove,
441};
442
443/**
444 * serdev_device_alloc() - Allocate a new serdev device
445 * @ctrl: associated controller
446 *
447 * Caller is responsible for either calling serdev_device_add() to add the
448 * newly allocated controller, or calling serdev_device_put() to discard it.
449 */
450struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
451{
452 struct serdev_device *serdev;
453
454 serdev = kzalloc(size: sizeof(*serdev), GFP_KERNEL);
455 if (!serdev)
456 return NULL;
457
458 serdev->ctrl = ctrl;
459 device_initialize(dev: &serdev->dev);
460 serdev->dev.parent = &ctrl->dev;
461 serdev->dev.bus = &serdev_bus_type;
462 serdev->dev.type = &serdev_device_type;
463 init_completion(x: &serdev->write_comp);
464 mutex_init(&serdev->write_lock);
465 return serdev;
466}
467EXPORT_SYMBOL_GPL(serdev_device_alloc);
468
469/**
470 * serdev_controller_alloc() - Allocate a new serdev controller
471 * @parent: parent device
472 * @size: size of private data
473 *
474 * Caller is responsible for either calling serdev_controller_add() to add the
475 * newly allocated controller, or calling serdev_controller_put() to discard it.
476 * The allocated private data region may be accessed via
477 * serdev_controller_get_drvdata()
478 */
479struct serdev_controller *serdev_controller_alloc(struct device *parent,
480 size_t size)
481{
482 struct serdev_controller *ctrl;
483 int id;
484
485 if (WARN_ON(!parent))
486 return NULL;
487
488 ctrl = kzalloc(size: sizeof(*ctrl) + size, GFP_KERNEL);
489 if (!ctrl)
490 return NULL;
491
492 id = ida_simple_get(&ctrl_ida, 0, 0, GFP_KERNEL);
493 if (id < 0) {
494 dev_err(parent,
495 "unable to allocate serdev controller identifier.\n");
496 goto err_free;
497 }
498
499 ctrl->nr = id;
500
501 device_initialize(dev: &ctrl->dev);
502 ctrl->dev.type = &serdev_ctrl_type;
503 ctrl->dev.bus = &serdev_bus_type;
504 ctrl->dev.parent = parent;
505 device_set_node(dev: &ctrl->dev, dev_fwnode(parent));
506 serdev_controller_set_drvdata(ctrl, data: &ctrl[1]);
507
508 dev_set_name(dev: &ctrl->dev, name: "serial%d", id);
509
510 pm_runtime_no_callbacks(dev: &ctrl->dev);
511 pm_suspend_ignore_children(dev: &ctrl->dev, enable: true);
512
513 dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
514 return ctrl;
515
516err_free:
517 kfree(objp: ctrl);
518
519 return NULL;
520}
521EXPORT_SYMBOL_GPL(serdev_controller_alloc);
522
523static int of_serdev_register_devices(struct serdev_controller *ctrl)
524{
525 struct device_node *node;
526 struct serdev_device *serdev = NULL;
527 int err;
528 bool found = false;
529
530 for_each_available_child_of_node(ctrl->dev.of_node, node) {
531 if (!of_get_property(node, name: "compatible", NULL))
532 continue;
533
534 dev_dbg(&ctrl->dev, "adding child %pOF\n", node);
535
536 serdev = serdev_device_alloc(ctrl);
537 if (!serdev)
538 continue;
539
540 device_set_node(dev: &serdev->dev, of_fwnode_handle(node));
541
542 err = serdev_device_add(serdev);
543 if (err) {
544 dev_err(&serdev->dev,
545 "failure adding device. status %pe\n",
546 ERR_PTR(err));
547 serdev_device_put(serdev);
548 } else
549 found = true;
550 }
551 if (!found)
552 return -ENODEV;
553
554 return 0;
555}
556
557#ifdef CONFIG_ACPI
558
559#define SERDEV_ACPI_MAX_SCAN_DEPTH 32
560
561struct acpi_serdev_lookup {
562 acpi_handle device_handle;
563 acpi_handle controller_handle;
564 int n;
565 int index;
566};
567
568/**
569 * serdev_acpi_get_uart_resource - Gets UARTSerialBus resource if type matches
570 * @ares: ACPI resource
571 * @uart: Pointer to UARTSerialBus resource will be returned here
572 *
573 * Checks if the given ACPI resource is of type UARTSerialBus.
574 * In this case, returns a pointer to it to the caller.
575 *
576 * Return: True if resource type is of UARTSerialBus, otherwise false.
577 */
578bool serdev_acpi_get_uart_resource(struct acpi_resource *ares,
579 struct acpi_resource_uart_serialbus **uart)
580{
581 struct acpi_resource_uart_serialbus *sb;
582
583 if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
584 return false;
585
586 sb = &ares->data.uart_serial_bus;
587 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_UART)
588 return false;
589
590 *uart = sb;
591 return true;
592}
593EXPORT_SYMBOL_GPL(serdev_acpi_get_uart_resource);
594
595static int acpi_serdev_parse_resource(struct acpi_resource *ares, void *data)
596{
597 struct acpi_serdev_lookup *lookup = data;
598 struct acpi_resource_uart_serialbus *sb;
599 acpi_status status;
600
601 if (!serdev_acpi_get_uart_resource(ares, &sb))
602 return 1;
603
604 if (lookup->index != -1 && lookup->n++ != lookup->index)
605 return 1;
606
607 status = acpi_get_handle(parent: lookup->device_handle,
608 pathname: sb->resource_source.string_ptr,
609 ret_handle: &lookup->controller_handle);
610 if (ACPI_FAILURE(status))
611 return 1;
612
613 /*
614 * NOTE: Ideally, we would also want to retrieve other properties here,
615 * once setting them before opening the device is supported by serdev.
616 */
617
618 return 1;
619}
620
621static int acpi_serdev_do_lookup(struct acpi_device *adev,
622 struct acpi_serdev_lookup *lookup)
623{
624 struct list_head resource_list;
625 int ret;
626
627 lookup->device_handle = acpi_device_handle(adev);
628 lookup->controller_handle = NULL;
629 lookup->n = 0;
630
631 INIT_LIST_HEAD(list: &resource_list);
632 ret = acpi_dev_get_resources(adev, list: &resource_list,
633 preproc: acpi_serdev_parse_resource, preproc_data: lookup);
634 acpi_dev_free_resource_list(list: &resource_list);
635
636 if (ret < 0)
637 return -EINVAL;
638
639 return 0;
640}
641
642static int acpi_serdev_check_resources(struct serdev_controller *ctrl,
643 struct acpi_device *adev)
644{
645 struct acpi_serdev_lookup lookup;
646 int ret;
647
648 if (acpi_bus_get_status(device: adev) || !adev->status.present)
649 return -EINVAL;
650
651 /* Look for UARTSerialBusV2 resource */
652 lookup.index = -1; // we only care for the last device
653
654 ret = acpi_serdev_do_lookup(adev, lookup: &lookup);
655 if (ret)
656 return ret;
657
658 /*
659 * Apple machines provide an empty resource template, so on those
660 * machines just look for immediate children with a "baud" property
661 * (from the _DSM method) instead.
662 */
663 if (!lookup.controller_handle && x86_apple_machine &&
664 !acpi_dev_get_property(adev, name: "baud", ACPI_TYPE_BUFFER, NULL))
665 acpi_get_parent(object: adev->handle, out_handle: &lookup.controller_handle);
666
667 /* Make sure controller and ResourceSource handle match */
668 if (!device_match_acpi_handle(dev: ctrl->dev.parent, handle: lookup.controller_handle))
669 return -ENODEV;
670
671 return 0;
672}
673
674static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
675 struct acpi_device *adev)
676{
677 struct serdev_device *serdev;
678 int err;
679
680 serdev = serdev_device_alloc(ctrl);
681 if (!serdev) {
682 dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
683 dev_name(&adev->dev));
684 return AE_NO_MEMORY;
685 }
686
687 ACPI_COMPANION_SET(&serdev->dev, adev);
688 acpi_device_set_enumerated(adev);
689
690 err = serdev_device_add(serdev);
691 if (err) {
692 dev_err(&serdev->dev,
693 "failure adding ACPI serdev device. status %pe\n",
694 ERR_PTR(err));
695 serdev_device_put(serdev);
696 }
697
698 return AE_OK;
699}
700
701static const struct acpi_device_id serdev_acpi_devices_blacklist[] = {
702 { "INT3511", 0 },
703 { "INT3512", 0 },
704 { },
705};
706
707static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
708 void *data, void **return_value)
709{
710 struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
711 struct serdev_controller *ctrl = data;
712
713 if (!adev || acpi_device_enumerated(adev))
714 return AE_OK;
715
716 /* Skip if black listed */
717 if (!acpi_match_device_ids(device: adev, ids: serdev_acpi_devices_blacklist))
718 return AE_OK;
719
720 if (acpi_serdev_check_resources(ctrl, adev))
721 return AE_OK;
722
723 return acpi_serdev_register_device(ctrl, adev);
724}
725
726
727static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
728{
729 acpi_status status;
730 bool skip;
731 int ret;
732
733 if (!has_acpi_companion(dev: ctrl->dev.parent))
734 return -ENODEV;
735
736 /*
737 * Skip registration on boards where the ACPI tables are known to
738 * contain buggy devices. Note serdev_controller_add() must still
739 * succeed in this case, so that the proper serdev devices can be
740 * added "manually" later.
741 */
742 ret = acpi_quirk_skip_serdev_enumeration(controller_parent: ctrl->dev.parent, skip: &skip);
743 if (ret)
744 return ret;
745 if (skip)
746 return 0;
747
748 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
749 SERDEV_ACPI_MAX_SCAN_DEPTH,
750 descending_callback: acpi_serdev_add_device, NULL, context: ctrl, NULL);
751 if (ACPI_FAILURE(status))
752 dev_warn(&ctrl->dev, "failed to enumerate serdev slaves\n");
753
754 if (!ctrl->serdev)
755 return -ENODEV;
756
757 return 0;
758}
759#else
760static inline int acpi_serdev_register_devices(struct serdev_controller *ctrl)
761{
762 return -ENODEV;
763}
764#endif /* CONFIG_ACPI */
765
766/**
767 * serdev_controller_add() - Add an serdev controller
768 * @ctrl: controller to be registered.
769 *
770 * Register a controller previously allocated via serdev_controller_alloc() with
771 * the serdev core.
772 */
773int serdev_controller_add(struct serdev_controller *ctrl)
774{
775 int ret_of, ret_acpi, ret;
776
777 /* Can't register until after driver model init */
778 if (WARN_ON(!is_registered))
779 return -EAGAIN;
780
781 ret = device_add(dev: &ctrl->dev);
782 if (ret)
783 return ret;
784
785 pm_runtime_enable(dev: &ctrl->dev);
786
787 ret_of = of_serdev_register_devices(ctrl);
788 ret_acpi = acpi_serdev_register_devices(ctrl);
789 if (ret_of && ret_acpi) {
790 dev_dbg(&ctrl->dev, "no devices registered: of:%pe acpi:%pe\n",
791 ERR_PTR(ret_of), ERR_PTR(ret_acpi));
792 ret = -ENODEV;
793 goto err_rpm_disable;
794 }
795
796 dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
797 ctrl->nr, &ctrl->dev);
798 return 0;
799
800err_rpm_disable:
801 pm_runtime_disable(dev: &ctrl->dev);
802 device_del(dev: &ctrl->dev);
803 return ret;
804};
805EXPORT_SYMBOL_GPL(serdev_controller_add);
806
807/* Remove a device associated with a controller */
808static int serdev_remove_device(struct device *dev, void *data)
809{
810 struct serdev_device *serdev = to_serdev_device(d: dev);
811 if (dev->type == &serdev_device_type)
812 serdev_device_remove(serdev);
813 return 0;
814}
815
816/**
817 * serdev_controller_remove(): remove an serdev controller
818 * @ctrl: controller to remove
819 *
820 * Remove a serdev controller. Caller is responsible for calling
821 * serdev_controller_put() to discard the allocated controller.
822 */
823void serdev_controller_remove(struct serdev_controller *ctrl)
824{
825 if (!ctrl)
826 return;
827
828 device_for_each_child(dev: &ctrl->dev, NULL, fn: serdev_remove_device);
829 pm_runtime_disable(dev: &ctrl->dev);
830 device_del(dev: &ctrl->dev);
831}
832EXPORT_SYMBOL_GPL(serdev_controller_remove);
833
834/**
835 * __serdev_device_driver_register() - Register client driver with serdev core
836 * @sdrv: client driver to be associated with client-device.
837 * @owner: client driver owner to set.
838 *
839 * This API will register the client driver with the serdev framework.
840 * It is typically called from the driver's module-init function.
841 */
842int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
843{
844 sdrv->driver.bus = &serdev_bus_type;
845 sdrv->driver.owner = owner;
846
847 /* force drivers to async probe so I/O is possible in probe */
848 sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
849
850 return driver_register(drv: &sdrv->driver);
851}
852EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
853
854static void __exit serdev_exit(void)
855{
856 bus_unregister(bus: &serdev_bus_type);
857 ida_destroy(ida: &ctrl_ida);
858}
859module_exit(serdev_exit);
860
861static int __init serdev_init(void)
862{
863 int ret;
864
865 ret = bus_register(bus: &serdev_bus_type);
866 if (ret)
867 return ret;
868
869 is_registered = true;
870 return 0;
871}
872/* Must be before serial drivers register */
873postcore_initcall(serdev_init);
874
875MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
876MODULE_LICENSE("GPL v2");
877MODULE_DESCRIPTION("Serial attached device bus");
878

source code of linux/drivers/tty/serdev/core.c