core.c

  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, 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(dev);
 63	kfree(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(dev);
 80	ida_free(&ctrl_ida, ctrl->nr);
 81	kfree(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, const 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(&serdev->dev, "%s-%d", dev_name(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(&serdev->dev);
120	if (err < 0) {
121		dev_err(&serdev->dev, "Failed to add serdev: %d\n", err);
122		goto err_clear_serdev;
123	}
124
125	dev_dbg(&serdev->dev, "serdev registered successfully\n");
126
127	return 0;
128
129err_clear_serdev:
130	ctrl->serdev = NULL;
131	return err;
132}
133EXPORT_SYMBOL_GPL(serdev_device_add);
134
135/**
136 * serdev_device_remove(): remove an serdev device
137 * @serdev:	serdev_device to be removed
138 */
139void serdev_device_remove(struct serdev_device *serdev)
140{
141	struct serdev_controller *ctrl = serdev->ctrl;
142
143	device_unregister(&serdev->dev);
144	ctrl->serdev = NULL;
145}
146EXPORT_SYMBOL_GPL(serdev_device_remove);
147
148int serdev_device_open(struct serdev_device *serdev)
149{
150	struct serdev_controller *ctrl = serdev->ctrl;
151	int ret;
152
153	if (!ctrl || !ctrl->ops->open)
154		return -EINVAL;
155
156	ret = ctrl->ops->open(ctrl);
157	if (ret)
158		return ret;
159
160	ret = pm_runtime_get_sync(&ctrl->dev);
161	if (ret < 0) {
162		pm_runtime_put_noidle(&ctrl->dev);
163		goto err_close;
164	}
165
166	return 0;
167
168err_close:
169	if (ctrl->ops->close)
170		ctrl->ops->close(ctrl);
171
172	return ret;
173}
174EXPORT_SYMBOL_GPL(serdev_device_open);
175
176void serdev_device_close(struct serdev_device *serdev)
177{
178	struct serdev_controller *ctrl = serdev->ctrl;
179
180	if (!ctrl || !ctrl->ops->close)
181		return;
182
183	pm_runtime_put(&ctrl->dev);
184
185	ctrl->ops->close(ctrl);
186}
187EXPORT_SYMBOL_GPL(serdev_device_close);
188
189static void devm_serdev_device_close(void *serdev)
190{
191	serdev_device_close(serdev);
192}
193
194int devm_serdev_device_open(struct device *dev, struct serdev_device *serdev)
195{
196	int ret;
197
198	ret = serdev_device_open(serdev);
199	if (ret)
200		return ret;
201
202	return devm_add_action_or_reset(dev, devm_serdev_device_close, serdev);
203}
204EXPORT_SYMBOL_GPL(devm_serdev_device_open);
205
206void serdev_device_write_wakeup(struct serdev_device *serdev)
207{
208	complete(&serdev->write_comp);
209}
210EXPORT_SYMBOL_GPL(serdev_device_write_wakeup);
211
212/**
213 * serdev_device_write_buf() - write data asynchronously
214 * @serdev:	serdev device
215 * @buf:	data to be written
216 * @count:	number of bytes to write
217 *
218 * Write data to the device asynchronously.
219 *
220 * Note that any accepted data has only been buffered by the controller; use
221 * serdev_device_wait_until_sent() to make sure the controller write buffer
222 * has actually been emptied.
223 *
224 * Return: The number of bytes written (less than count if not enough room in
225 * the write buffer), or a negative errno on errors.
226 */
227int serdev_device_write_buf(struct serdev_device *serdev, const u8 *buf, size_t count)
228{
229	struct serdev_controller *ctrl = serdev->ctrl;
230
231	if (!ctrl || !ctrl->ops->write_buf)
232		return -EINVAL;
233
234	return ctrl->ops->write_buf(ctrl, buf, count);
235}
236EXPORT_SYMBOL_GPL(serdev_device_write_buf);
237
238/**
239 * serdev_device_write() - write data synchronously
240 * @serdev:	serdev device
241 * @buf:	data to be written
242 * @count:	number of bytes to write
243 * @timeout:	timeout in jiffies, or 0 to wait indefinitely
244 *
245 * Write data to the device synchronously by repeatedly calling
246 * serdev_device_write() until the controller has accepted all data (unless
247 * interrupted by a timeout or a signal).
248 *
249 * Note that any accepted data has only been buffered by the controller; use
250 * serdev_device_wait_until_sent() to make sure the controller write buffer
251 * has actually been emptied.
252 *
253 * Note that this function depends on serdev_device_write_wakeup() being
254 * called in the serdev driver write_wakeup() callback.
255 *
256 * Return: The number of bytes written (less than count if interrupted),
257 * -ETIMEDOUT or -ERESTARTSYS if interrupted before any bytes were written, or
258 * a negative errno on errors.
259 */
260ssize_t serdev_device_write(struct serdev_device *serdev, const u8 *buf,
261			    size_t count, long timeout)
262{
263	struct serdev_controller *ctrl = serdev->ctrl;
264	size_t written = 0;
265	ssize_t ret;
266
267	if (!ctrl || !ctrl->ops->write_buf || !serdev->ops->write_wakeup)
268		return -EINVAL;
269
270	if (timeout == 0)
271		timeout = MAX_SCHEDULE_TIMEOUT;
272
273	mutex_lock(&serdev->write_lock);
274	do {
275		reinit_completion(&serdev->write_comp);
276
277		ret = ctrl->ops->write_buf(ctrl, buf, count);
278		if (ret < 0)
279			break;
280
281		written += ret;
282		buf += ret;
283		count -= ret;
284
285		if (count == 0)
286			break;
287
288		timeout = wait_for_completion_interruptible_timeout(&serdev->write_comp,
289								    timeout);
290	} while (timeout > 0);
291	mutex_unlock(&serdev->write_lock);
292
293	if (ret < 0)
294		return ret;
295
296	if (timeout <= 0 && written == 0) {
297		if (timeout == -ERESTARTSYS)
298			return -ERESTARTSYS;
299		else
300			return -ETIMEDOUT;
301	}
302
303	return written;
304}
305EXPORT_SYMBOL_GPL(serdev_device_write);
306
307void serdev_device_write_flush(struct serdev_device *serdev)
308{
309	struct serdev_controller *ctrl = serdev->ctrl;
310
311	if (!ctrl || !ctrl->ops->write_flush)
312		return;
313
314	ctrl->ops->write_flush(ctrl);
315}
316EXPORT_SYMBOL_GPL(serdev_device_write_flush);
317
318unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
319{
320	struct serdev_controller *ctrl = serdev->ctrl;
321
322	if (!ctrl || !ctrl->ops->set_baudrate)
323		return 0;
324
325	return ctrl->ops->set_baudrate(ctrl, speed);
326
327}
328EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
329
330void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
331{
332	struct serdev_controller *ctrl = serdev->ctrl;
333
334	if (!ctrl || !ctrl->ops->set_flow_control)
335		return;
336
337	ctrl->ops->set_flow_control(ctrl, enable);
338}
339EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
340
341int serdev_device_set_parity(struct serdev_device *serdev,
342			     enum serdev_parity parity)
343{
344	struct serdev_controller *ctrl = serdev->ctrl;
345
346	if (!ctrl || !ctrl->ops->set_parity)
347		return -EOPNOTSUPP;
348
349	return ctrl->ops->set_parity(ctrl, parity);
350}
351EXPORT_SYMBOL_GPL(serdev_device_set_parity);
352
353void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
354{
355	struct serdev_controller *ctrl = serdev->ctrl;
356
357	if (!ctrl || !ctrl->ops->wait_until_sent)
358		return;
359
360	ctrl->ops->wait_until_sent(ctrl, timeout);
361}
362EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
363
364int serdev_device_get_tiocm(struct serdev_device *serdev)
365{
366	struct serdev_controller *ctrl = serdev->ctrl;
367
368	if (!ctrl || !ctrl->ops->get_tiocm)
369		return -EOPNOTSUPP;
370
371	return ctrl->ops->get_tiocm(ctrl);
372}
373EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
374
375int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
376{
377	struct serdev_controller *ctrl = serdev->ctrl;
378
379	if (!ctrl || !ctrl->ops->set_tiocm)
380		return -EOPNOTSUPP;
381
382	return ctrl->ops->set_tiocm(ctrl, set, clear);
383}
384EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
385
386int serdev_device_break_ctl(struct serdev_device *serdev, int break_state)
387{
388	struct serdev_controller *ctrl = serdev->ctrl;
389
390	if (!ctrl || !ctrl->ops->break_ctl)
391		return -EOPNOTSUPP;
392
393	return ctrl->ops->break_ctl(ctrl, break_state);
394}
395EXPORT_SYMBOL_GPL(serdev_device_break_ctl);
396
397static int serdev_drv_probe(struct device *dev)
398{
399	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
400	int ret;
401
402	ret = dev_pm_domain_attach(dev, PD_FLAG_ATTACH_POWER_ON |
403					PD_FLAG_DETACH_POWER_OFF);
404	if (ret)
405		return ret;
406
407	return sdrv->probe(to_serdev_device(dev));
408}
409
410static void serdev_drv_remove(struct device *dev)
411{
412	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
413	if (sdrv->remove)
414		sdrv->remove(to_serdev_device(dev));
415}
416
417static const struct bus_type serdev_bus_type = {
418	.name		= "serial",
419	.match		= serdev_device_match,
420	.probe		= serdev_drv_probe,
421	.remove		= serdev_drv_remove,
422};
423
424/**
425 * serdev_device_alloc() - Allocate a new serdev device
426 * @ctrl:	associated controller
427 *
428 * Caller is responsible for either calling serdev_device_add() to add the
429 * newly allocated controller, or calling serdev_device_put() to discard it.
430 */
431struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
432{
433	struct serdev_device *serdev;
434
435	serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
436	if (!serdev)
437		return NULL;
438
439	serdev->ctrl = ctrl;
440	device_initialize(&serdev->dev);
441	serdev->dev.parent = &ctrl->dev;
442	serdev->dev.bus = &serdev_bus_type;
443	serdev->dev.type = &serdev_device_type;
444	init_completion(&serdev->write_comp);
445	mutex_init(&serdev->write_lock);
446	return serdev;
447}
448EXPORT_SYMBOL_GPL(serdev_device_alloc);
449
450/**
451 * serdev_controller_alloc() - Allocate a new serdev controller
452 * @host:	serial port hardware controller device
453 * @parent:	parent device
454 * @size:	size of private data
455 *
456 * Caller is responsible for either calling serdev_controller_add() to add the
457 * newly allocated controller, or calling serdev_controller_put() to discard it.
458 * The allocated private data region may be accessed via
459 * serdev_controller_get_drvdata()
460 */
461struct serdev_controller *serdev_controller_alloc(struct device *host,
462						  struct device *parent,
463						  size_t size)
464{
465	struct serdev_controller *ctrl;
466	int id;
467
468	if (WARN_ON(!parent))
469		return NULL;
470
471	ctrl = kzalloc(sizeof(*ctrl) + size, GFP_KERNEL);
472	if (!ctrl)
473		return NULL;
474
475	id = ida_alloc(&ctrl_ida, GFP_KERNEL);
476	if (id < 0) {
477		dev_err(parent,
478			"unable to allocate serdev controller identifier.\n");
479		goto err_free;
480	}
481
482	ctrl->nr = id;
483
484	device_initialize(&ctrl->dev);
485	ctrl->dev.type = &serdev_ctrl_type;
486	ctrl->dev.bus = &serdev_bus_type;
487	ctrl->dev.parent = parent;
488	ctrl->host = host;
489	device_set_node(&ctrl->dev, dev_fwnode(host));
490	serdev_controller_set_drvdata(ctrl, &ctrl[1]);
491
492	dev_set_name(&ctrl->dev, "serial%d", id);
493
494	pm_runtime_no_callbacks(&ctrl->dev);
495	pm_suspend_ignore_children(&ctrl->dev, true);
496
497	dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
498	return ctrl;
499
500err_free:
501	kfree(ctrl);
502
503	return NULL;
504}
505EXPORT_SYMBOL_GPL(serdev_controller_alloc);
506
507static int of_serdev_register_devices(struct serdev_controller *ctrl)
508{
509	struct device_node *node;
510	struct serdev_device *serdev = NULL;
511	int err;
512	bool found = false;
513
514	for_each_available_child_of_node(ctrl->dev.of_node, node) {
515		if (!of_property_present(node, "compatible"))
516			continue;
517
518		dev_dbg(&ctrl->dev, "adding child %pOF\n", node);
519
520		serdev = serdev_device_alloc(ctrl);
521		if (!serdev)
522			continue;
523
524		device_set_node(&serdev->dev, of_fwnode_handle(node));
525
526		err = serdev_device_add(serdev);
527		if (err) {
528			dev_err(&serdev->dev,
529				"failure adding device. status %pe\n",
530				ERR_PTR(err));
531			serdev_device_put(serdev);
532		} else
533			found = true;
534	}
535	if (!found)
536		return -ENODEV;
537
538	return 0;
539}
540
541#ifdef CONFIG_ACPI
542
543#define SERDEV_ACPI_MAX_SCAN_DEPTH 32
544
545struct acpi_serdev_lookup {
546	acpi_handle device_handle;
547	acpi_handle controller_handle;
548	int n;
549	int index;
550};
551
552/**
553 * serdev_acpi_get_uart_resource - Gets UARTSerialBus resource if type matches
554 * @ares:	ACPI resource
555 * @uart:	Pointer to UARTSerialBus resource will be returned here
556 *
557 * Checks if the given ACPI resource is of type UARTSerialBus.
558 * In this case, returns a pointer to it to the caller.
559 *
560 * Return: True if resource type is of UARTSerialBus, otherwise false.
561 */
562bool serdev_acpi_get_uart_resource(struct acpi_resource *ares,
563				   struct acpi_resource_uart_serialbus **uart)
564{
565	struct acpi_resource_uart_serialbus *sb;
566
567	if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
568		return false;
569
570	sb = &ares->data.uart_serial_bus;
571	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_UART)
572		return false;
573
574	*uart = sb;
575	return true;
576}
577EXPORT_SYMBOL_GPL(serdev_acpi_get_uart_resource);
578
579static int acpi_serdev_parse_resource(struct acpi_resource *ares, void *data)
580{
581	struct acpi_serdev_lookup *lookup = data;
582	struct acpi_resource_uart_serialbus *sb;
583	acpi_status status;
584
585	if (!serdev_acpi_get_uart_resource(ares, &sb))
586		return 1;
587
588	if (lookup->index != -1 && lookup->n++ != lookup->index)
589		return 1;
590
591	status = acpi_get_handle(lookup->device_handle,
592				 sb->resource_source.string_ptr,
593				 &lookup->controller_handle);
594	if (ACPI_FAILURE(status))
595		return 1;
596
597	/*
598	 * NOTE: Ideally, we would also want to retrieve other properties here,
599	 * once setting them before opening the device is supported by serdev.
600	 */
601
602	return 1;
603}
604
605static int acpi_serdev_do_lookup(struct acpi_device *adev,
606                                 struct acpi_serdev_lookup *lookup)
607{
608	struct list_head resource_list;
609	int ret;
610
611	lookup->device_handle = acpi_device_handle(adev);
612	lookup->controller_handle = NULL;
613	lookup->n = 0;
614
615	INIT_LIST_HEAD(&resource_list);
616	ret = acpi_dev_get_resources(adev, &resource_list,
617				     acpi_serdev_parse_resource, lookup);
618	acpi_dev_free_resource_list(&resource_list);
619
620	if (ret < 0)
621		return -EINVAL;
622
623	return 0;
624}
625
626static int acpi_serdev_check_resources(struct serdev_controller *ctrl,
627				       struct acpi_device *adev)
628{
629	struct acpi_serdev_lookup lookup;
630	int ret;
631
632	if (acpi_bus_get_status(adev) || !adev->status.present)
633		return -EINVAL;
634
635	/* Look for UARTSerialBusV2 resource */
636	lookup.index = -1;	// we only care for the last device
637
638	ret = acpi_serdev_do_lookup(adev, &lookup);
639	if (ret)
640		return ret;
641
642	/*
643	 * Apple machines provide an empty resource template, so on those
644	 * machines just look for immediate children with a "baud" property
645	 * (from the _DSM method) instead.
646	 */
647	if (!lookup.controller_handle && x86_apple_machine &&
648	    !acpi_dev_get_property(adev, "baud", ACPI_TYPE_BUFFER, NULL))
649		acpi_get_parent(adev->handle, &lookup.controller_handle);
650
651	/* Make sure controller and ResourceSource handle match */
652	if (!device_match_acpi_handle(ctrl->host, lookup.controller_handle))
653		return -ENODEV;
654
655	return 0;
656}
657
658static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
659					       struct acpi_device *adev)
660{
661	struct serdev_device *serdev;
662	int err;
663
664	serdev = serdev_device_alloc(ctrl);
665	if (!serdev) {
666		dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
667			dev_name(&adev->dev));
668		return AE_NO_MEMORY;
669	}
670
671	ACPI_COMPANION_SET(&serdev->dev, adev);
672	acpi_device_set_enumerated(adev);
673
674	err = serdev_device_add(serdev);
675	if (err) {
676		dev_err(&serdev->dev,
677			"failure adding ACPI serdev device. status %pe\n",
678			ERR_PTR(err));
679		serdev_device_put(serdev);
680	}
681
682	return AE_OK;
683}
684
685static const struct acpi_device_id serdev_acpi_devices_blacklist[] = {
686	{ "INT3511", 0 },
687	{ "INT3512", 0 },
688	{ },
689};
690
691static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
692					  void *data, void **return_value)
693{
694	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
695	struct serdev_controller *ctrl = data;
696
697	if (!adev || acpi_device_enumerated(adev))
698		return AE_OK;
699
700	/* Skip if black listed */
701	if (!acpi_match_device_ids(adev, serdev_acpi_devices_blacklist))
702		return AE_OK;
703
704	if (acpi_serdev_check_resources(ctrl, adev))
705		return AE_OK;
706
707	return acpi_serdev_register_device(ctrl, adev);
708}
709
710
711static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
712{
713	acpi_status status;
714	bool skip;
715	int ret;
716
717	if (!has_acpi_companion(ctrl->host))
718		return -ENODEV;
719
720	/*
721	 * Skip registration on boards where the ACPI tables are known to
722	 * contain buggy devices. Note serdev_controller_add() must still
723	 * succeed in this case, so that the proper serdev devices can be
724	 * added "manually" later.
725	 */
726	ret = acpi_quirk_skip_serdev_enumeration(ctrl->host, &skip);
727	if (ret)
728		return ret;
729	if (skip)
730		return 0;
731
732	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
733				     SERDEV_ACPI_MAX_SCAN_DEPTH,
734				     acpi_serdev_add_device, NULL, ctrl, NULL);
735	if (ACPI_FAILURE(status))
736		dev_warn(&ctrl->dev, "failed to enumerate serdev slaves\n");
737
738	if (!ctrl->serdev)
739		return -ENODEV;
740
741	return 0;
742}
743#else
744static inline int acpi_serdev_register_devices(struct serdev_controller *ctrl)
745{
746	return -ENODEV;
747}
748#endif /* CONFIG_ACPI */
749
750/**
751 * serdev_controller_add() - Add an serdev controller
752 * @ctrl:	controller to be registered.
753 *
754 * Register a controller previously allocated via serdev_controller_alloc() with
755 * the serdev core.
756 */
757int serdev_controller_add(struct serdev_controller *ctrl)
758{
759	int ret_of, ret_acpi, ret;
760
761	/* Can't register until after driver model init */
762	if (WARN_ON(!is_registered))
763		return -EAGAIN;
764
765	ret = device_add(&ctrl->dev);
766	if (ret)
767		return ret;
768
769	pm_runtime_enable(&ctrl->dev);
770
771	ret_of = of_serdev_register_devices(ctrl);
772	ret_acpi = acpi_serdev_register_devices(ctrl);
773	if (ret_of && ret_acpi) {
774		dev_dbg(&ctrl->dev, "no devices registered: of:%pe acpi:%pe\n",
775			ERR_PTR(ret_of), ERR_PTR(ret_acpi));
776		ret = -ENODEV;
777		goto err_rpm_disable;
778	}
779
780	dev_dbg(&ctrl->dev, "serdev controller registered: dev:%p\n", &ctrl->dev);
781	return 0;
782
783err_rpm_disable:
784	pm_runtime_disable(&ctrl->dev);
785	device_del(&ctrl->dev);
786	return ret;
787};
788EXPORT_SYMBOL_GPL(serdev_controller_add);
789
790/* Remove a device associated with a controller */
791static int serdev_remove_device(struct device *dev, void *data)
792{
793	struct serdev_device *serdev = to_serdev_device(dev);
794	if (dev->type == &serdev_device_type)
795		serdev_device_remove(serdev);
796	return 0;
797}
798
799/**
800 * serdev_controller_remove(): remove an serdev controller
801 * @ctrl:	controller to remove
802 *
803 * Remove a serdev controller.  Caller is responsible for calling
804 * serdev_controller_put() to discard the allocated controller.
805 */
806void serdev_controller_remove(struct serdev_controller *ctrl)
807{
808	if (!ctrl)
809		return;
810
811	device_for_each_child(&ctrl->dev, NULL, serdev_remove_device);
812	pm_runtime_disable(&ctrl->dev);
813	device_del(&ctrl->dev);
814}
815EXPORT_SYMBOL_GPL(serdev_controller_remove);
816
817/**
818 * __serdev_device_driver_register() - Register client driver with serdev core
819 * @sdrv:	client driver to be associated with client-device.
820 * @owner:	client driver owner to set.
821 *
822 * This API will register the client driver with the serdev framework.
823 * It is typically called from the driver's module-init function.
824 */
825int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
826{
827	sdrv->driver.bus = &serdev_bus_type;
828	sdrv->driver.owner = owner;
829
830	/* force drivers to async probe so I/O is possible in probe */
831        sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
832
833	return driver_register(&sdrv->driver);
834}
835EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
836
837static void __exit serdev_exit(void)
838{
839	bus_unregister(&serdev_bus_type);
840	ida_destroy(&ctrl_ida);
841}
842module_exit(serdev_exit);
843
844static int __init serdev_init(void)
845{
846	int ret;
847
848	ret = bus_register(&serdev_bus_type);
849	if (ret)
850		return ret;
851
852	is_registered = true;
853	return 0;
854}
855/* Must be before serial drivers register */
856postcore_initcall(serdev_init);
857
858MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
859MODULE_LICENSE("GPL v2");
860MODULE_DESCRIPTION("Serial attached device bus");