xref: /linux/drivers/tty/serdev/core.c (revision 3a39d672e7f48b8d6b91a09afa4b55352773b4b5)
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  
25  static bool is_registered;
26  static DEFINE_IDA(ctrl_ida);
27  
modalias_show(struct device * dev,struct device_attribute * attr,char * buf)28  static 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  }
39  static DEVICE_ATTR_RO(modalias);
40  
41  static struct attribute *serdev_device_attrs[] = {
42  	&dev_attr_modalias.attr,
43  	NULL,
44  };
45  ATTRIBUTE_GROUPS(serdev_device);
46  
serdev_device_uevent(const struct device * dev,struct kobj_uevent_env * env)47  static 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  
serdev_device_release(struct device * dev)60  static void serdev_device_release(struct device *dev)
61  {
62  	struct serdev_device *serdev = to_serdev_device(dev);
63  	kfree(serdev);
64  }
65  
66  static const struct device_type serdev_device_type = {
67  	.groups		= serdev_device_groups,
68  	.uevent		= serdev_device_uevent,
69  	.release	= serdev_device_release,
70  };
71  
is_serdev_device(const struct device * dev)72  static bool is_serdev_device(const struct device *dev)
73  {
74  	return dev->type == &serdev_device_type;
75  }
76  
serdev_ctrl_release(struct device * dev)77  static 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  
84  static const struct device_type serdev_ctrl_type = {
85  	.release	= serdev_ctrl_release,
86  };
87  
serdev_device_match(struct device * dev,const struct device_driver * drv)88  static 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   */
serdev_device_add(struct serdev_device * serdev)104  int 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, "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  
130  err_clear_serdev:
131  	ctrl->serdev = NULL;
132  	return err;
133  }
134  EXPORT_SYMBOL_GPL(serdev_device_add);
135  
136  /**
137   * serdev_device_remove(): remove an serdev device
138   * @serdev:	serdev_device to be removed
139   */
serdev_device_remove(struct serdev_device * serdev)140  void serdev_device_remove(struct serdev_device *serdev)
141  {
142  	struct serdev_controller *ctrl = serdev->ctrl;
143  
144  	device_unregister(&serdev->dev);
145  	ctrl->serdev = NULL;
146  }
147  EXPORT_SYMBOL_GPL(serdev_device_remove);
148  
serdev_device_open(struct serdev_device * serdev)149  int 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(&ctrl->dev);
162  	if (ret < 0) {
163  		pm_runtime_put_noidle(&ctrl->dev);
164  		goto err_close;
165  	}
166  
167  	return 0;
168  
169  err_close:
170  	if (ctrl->ops->close)
171  		ctrl->ops->close(ctrl);
172  
173  	return ret;
174  }
175  EXPORT_SYMBOL_GPL(serdev_device_open);
176  
serdev_device_close(struct serdev_device * serdev)177  void 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(&ctrl->dev);
185  
186  	ctrl->ops->close(ctrl);
187  }
188  EXPORT_SYMBOL_GPL(serdev_device_close);
189  
devm_serdev_device_close(void * serdev)190  static void devm_serdev_device_close(void *serdev)
191  {
192  	serdev_device_close(serdev);
193  }
194  
devm_serdev_device_open(struct device * dev,struct serdev_device * serdev)195  int 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  }
205  EXPORT_SYMBOL_GPL(devm_serdev_device_open);
206  
serdev_device_write_wakeup(struct serdev_device * serdev)207  void serdev_device_write_wakeup(struct serdev_device *serdev)
208  {
209  	complete(&serdev->write_comp);
210  }
211  EXPORT_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   */
serdev_device_write_buf(struct serdev_device * serdev,const u8 * buf,size_t count)228  int serdev_device_write_buf(struct serdev_device *serdev, const u8 *buf, size_t count)
229  {
230  	struct serdev_controller *ctrl = serdev->ctrl;
231  
232  	if (!ctrl || !ctrl->ops->write_buf)
233  		return -EINVAL;
234  
235  	return ctrl->ops->write_buf(ctrl, buf, count);
236  }
237  EXPORT_SYMBOL_GPL(serdev_device_write_buf);
238  
239  /**
240   * serdev_device_write() - write data synchronously
241   * @serdev:	serdev device
242   * @buf:	data to be written
243   * @count:	number of bytes to write
244   * @timeout:	timeout in jiffies, or 0 to wait indefinitely
245   *
246   * Write data to the device synchronously by repeatedly calling
247   * serdev_device_write() until the controller has accepted all data (unless
248   * interrupted by a timeout or a signal).
249   *
250   * Note that any accepted data has only been buffered by the controller; use
251   * serdev_device_wait_until_sent() to make sure the controller write buffer
252   * has actually been emptied.
253   *
254   * Note that this function depends on serdev_device_write_wakeup() being
255   * called in the serdev driver write_wakeup() callback.
256   *
257   * Return: The number of bytes written (less than count if interrupted),
258   * -ETIMEDOUT or -ERESTARTSYS if interrupted before any bytes were written, or
259   * a negative errno on errors.
260   */
serdev_device_write(struct serdev_device * serdev,const u8 * buf,size_t count,long timeout)261  ssize_t serdev_device_write(struct serdev_device *serdev, const u8 *buf,
262  			    size_t count, long timeout)
263  {
264  	struct serdev_controller *ctrl = serdev->ctrl;
265  	size_t written = 0;
266  	ssize_t ret;
267  
268  	if (!ctrl || !ctrl->ops->write_buf || !serdev->ops->write_wakeup)
269  		return -EINVAL;
270  
271  	if (timeout == 0)
272  		timeout = MAX_SCHEDULE_TIMEOUT;
273  
274  	mutex_lock(&serdev->write_lock);
275  	do {
276  		reinit_completion(&serdev->write_comp);
277  
278  		ret = ctrl->ops->write_buf(ctrl, buf, count);
279  		if (ret < 0)
280  			break;
281  
282  		written += ret;
283  		buf += ret;
284  		count -= ret;
285  
286  		if (count == 0)
287  			break;
288  
289  		timeout = wait_for_completion_interruptible_timeout(&serdev->write_comp,
290  								    timeout);
291  	} while (timeout > 0);
292  	mutex_unlock(&serdev->write_lock);
293  
294  	if (ret < 0)
295  		return ret;
296  
297  	if (timeout <= 0 && written == 0) {
298  		if (timeout == -ERESTARTSYS)
299  			return -ERESTARTSYS;
300  		else
301  			return -ETIMEDOUT;
302  	}
303  
304  	return written;
305  }
306  EXPORT_SYMBOL_GPL(serdev_device_write);
307  
serdev_device_write_flush(struct serdev_device * serdev)308  void serdev_device_write_flush(struct serdev_device *serdev)
309  {
310  	struct serdev_controller *ctrl = serdev->ctrl;
311  
312  	if (!ctrl || !ctrl->ops->write_flush)
313  		return;
314  
315  	ctrl->ops->write_flush(ctrl);
316  }
317  EXPORT_SYMBOL_GPL(serdev_device_write_flush);
318  
serdev_device_write_room(struct serdev_device * serdev)319  int serdev_device_write_room(struct serdev_device *serdev)
320  {
321  	struct serdev_controller *ctrl = serdev->ctrl;
322  
323  	if (!ctrl || !ctrl->ops->write_room)
324  		return 0;
325  
326  	return serdev->ctrl->ops->write_room(ctrl);
327  }
328  EXPORT_SYMBOL_GPL(serdev_device_write_room);
329  
serdev_device_set_baudrate(struct serdev_device * serdev,unsigned int speed)330  unsigned int serdev_device_set_baudrate(struct serdev_device *serdev, unsigned int speed)
331  {
332  	struct serdev_controller *ctrl = serdev->ctrl;
333  
334  	if (!ctrl || !ctrl->ops->set_baudrate)
335  		return 0;
336  
337  	return ctrl->ops->set_baudrate(ctrl, speed);
338  
339  }
340  EXPORT_SYMBOL_GPL(serdev_device_set_baudrate);
341  
serdev_device_set_flow_control(struct serdev_device * serdev,bool enable)342  void serdev_device_set_flow_control(struct serdev_device *serdev, bool enable)
343  {
344  	struct serdev_controller *ctrl = serdev->ctrl;
345  
346  	if (!ctrl || !ctrl->ops->set_flow_control)
347  		return;
348  
349  	ctrl->ops->set_flow_control(ctrl, enable);
350  }
351  EXPORT_SYMBOL_GPL(serdev_device_set_flow_control);
352  
serdev_device_set_parity(struct serdev_device * serdev,enum serdev_parity parity)353  int serdev_device_set_parity(struct serdev_device *serdev,
354  			     enum serdev_parity parity)
355  {
356  	struct serdev_controller *ctrl = serdev->ctrl;
357  
358  	if (!ctrl || !ctrl->ops->set_parity)
359  		return -EOPNOTSUPP;
360  
361  	return ctrl->ops->set_parity(ctrl, parity);
362  }
363  EXPORT_SYMBOL_GPL(serdev_device_set_parity);
364  
serdev_device_wait_until_sent(struct serdev_device * serdev,long timeout)365  void serdev_device_wait_until_sent(struct serdev_device *serdev, long timeout)
366  {
367  	struct serdev_controller *ctrl = serdev->ctrl;
368  
369  	if (!ctrl || !ctrl->ops->wait_until_sent)
370  		return;
371  
372  	ctrl->ops->wait_until_sent(ctrl, timeout);
373  }
374  EXPORT_SYMBOL_GPL(serdev_device_wait_until_sent);
375  
serdev_device_get_tiocm(struct serdev_device * serdev)376  int serdev_device_get_tiocm(struct serdev_device *serdev)
377  {
378  	struct serdev_controller *ctrl = serdev->ctrl;
379  
380  	if (!ctrl || !ctrl->ops->get_tiocm)
381  		return -EOPNOTSUPP;
382  
383  	return ctrl->ops->get_tiocm(ctrl);
384  }
385  EXPORT_SYMBOL_GPL(serdev_device_get_tiocm);
386  
serdev_device_set_tiocm(struct serdev_device * serdev,int set,int clear)387  int serdev_device_set_tiocm(struct serdev_device *serdev, int set, int clear)
388  {
389  	struct serdev_controller *ctrl = serdev->ctrl;
390  
391  	if (!ctrl || !ctrl->ops->set_tiocm)
392  		return -EOPNOTSUPP;
393  
394  	return ctrl->ops->set_tiocm(ctrl, set, clear);
395  }
396  EXPORT_SYMBOL_GPL(serdev_device_set_tiocm);
397  
serdev_device_break_ctl(struct serdev_device * serdev,int break_state)398  int serdev_device_break_ctl(struct serdev_device *serdev, int break_state)
399  {
400  	struct serdev_controller *ctrl = serdev->ctrl;
401  
402  	if (!ctrl || !ctrl->ops->break_ctl)
403  		return -EOPNOTSUPP;
404  
405  	return ctrl->ops->break_ctl(ctrl, break_state);
406  }
407  EXPORT_SYMBOL_GPL(serdev_device_break_ctl);
408  
serdev_drv_probe(struct device * dev)409  static int serdev_drv_probe(struct device *dev)
410  {
411  	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
412  	int ret;
413  
414  	ret = dev_pm_domain_attach(dev, true);
415  	if (ret)
416  		return ret;
417  
418  	ret = sdrv->probe(to_serdev_device(dev));
419  	if (ret)
420  		dev_pm_domain_detach(dev, true);
421  
422  	return ret;
423  }
424  
serdev_drv_remove(struct device * dev)425  static void serdev_drv_remove(struct device *dev)
426  {
427  	const struct serdev_device_driver *sdrv = to_serdev_device_driver(dev->driver);
428  	if (sdrv->remove)
429  		sdrv->remove(to_serdev_device(dev));
430  
431  	dev_pm_domain_detach(dev, true);
432  }
433  
434  static const struct bus_type serdev_bus_type = {
435  	.name		= "serial",
436  	.match		= serdev_device_match,
437  	.probe		= serdev_drv_probe,
438  	.remove		= serdev_drv_remove,
439  };
440  
441  /**
442   * serdev_device_alloc() - Allocate a new serdev device
443   * @ctrl:	associated controller
444   *
445   * Caller is responsible for either calling serdev_device_add() to add the
446   * newly allocated controller, or calling serdev_device_put() to discard it.
447   */
serdev_device_alloc(struct serdev_controller * ctrl)448  struct serdev_device *serdev_device_alloc(struct serdev_controller *ctrl)
449  {
450  	struct serdev_device *serdev;
451  
452  	serdev = kzalloc(sizeof(*serdev), GFP_KERNEL);
453  	if (!serdev)
454  		return NULL;
455  
456  	serdev->ctrl = ctrl;
457  	device_initialize(&serdev->dev);
458  	serdev->dev.parent = &ctrl->dev;
459  	serdev->dev.bus = &serdev_bus_type;
460  	serdev->dev.type = &serdev_device_type;
461  	init_completion(&serdev->write_comp);
462  	mutex_init(&serdev->write_lock);
463  	return serdev;
464  }
465  EXPORT_SYMBOL_GPL(serdev_device_alloc);
466  
467  /**
468   * serdev_controller_alloc() - Allocate a new serdev controller
469   * @host:	serial port hardware controller device
470   * @parent:	parent device
471   * @size:	size of private data
472   *
473   * Caller is responsible for either calling serdev_controller_add() to add the
474   * newly allocated controller, or calling serdev_controller_put() to discard it.
475   * The allocated private data region may be accessed via
476   * serdev_controller_get_drvdata()
477   */
serdev_controller_alloc(struct device * host,struct device * parent,size_t size)478  struct serdev_controller *serdev_controller_alloc(struct device *host,
479  						  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(sizeof(*ctrl) + size, GFP_KERNEL);
489  	if (!ctrl)
490  		return NULL;
491  
492  	id = ida_alloc(&ctrl_ida, 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(&ctrl->dev);
502  	ctrl->dev.type = &serdev_ctrl_type;
503  	ctrl->dev.bus = &serdev_bus_type;
504  	ctrl->dev.parent = parent;
505  	ctrl->host = host;
506  	device_set_node(&ctrl->dev, dev_fwnode(host));
507  	serdev_controller_set_drvdata(ctrl, &ctrl[1]);
508  
509  	dev_set_name(&ctrl->dev, "serial%d", id);
510  
511  	pm_runtime_no_callbacks(&ctrl->dev);
512  	pm_suspend_ignore_children(&ctrl->dev, true);
513  
514  	dev_dbg(&ctrl->dev, "allocated controller 0x%p id %d\n", ctrl, id);
515  	return ctrl;
516  
517  err_free:
518  	kfree(ctrl);
519  
520  	return NULL;
521  }
522  EXPORT_SYMBOL_GPL(serdev_controller_alloc);
523  
of_serdev_register_devices(struct serdev_controller * ctrl)524  static int of_serdev_register_devices(struct serdev_controller *ctrl)
525  {
526  	struct device_node *node;
527  	struct serdev_device *serdev = NULL;
528  	int err;
529  	bool found = false;
530  
531  	for_each_available_child_of_node(ctrl->dev.of_node, node) {
532  		if (!of_property_present(node, "compatible"))
533  			continue;
534  
535  		dev_dbg(&ctrl->dev, "adding child %pOF\n", node);
536  
537  		serdev = serdev_device_alloc(ctrl);
538  		if (!serdev)
539  			continue;
540  
541  		device_set_node(&serdev->dev, of_fwnode_handle(node));
542  
543  		err = serdev_device_add(serdev);
544  		if (err) {
545  			dev_err(&serdev->dev,
546  				"failure adding device. status %pe\n",
547  				ERR_PTR(err));
548  			serdev_device_put(serdev);
549  		} else
550  			found = true;
551  	}
552  	if (!found)
553  		return -ENODEV;
554  
555  	return 0;
556  }
557  
558  #ifdef CONFIG_ACPI
559  
560  #define SERDEV_ACPI_MAX_SCAN_DEPTH 32
561  
562  struct acpi_serdev_lookup {
563  	acpi_handle device_handle;
564  	acpi_handle controller_handle;
565  	int n;
566  	int index;
567  };
568  
569  /**
570   * serdev_acpi_get_uart_resource - Gets UARTSerialBus resource if type matches
571   * @ares:	ACPI resource
572   * @uart:	Pointer to UARTSerialBus resource will be returned here
573   *
574   * Checks if the given ACPI resource is of type UARTSerialBus.
575   * In this case, returns a pointer to it to the caller.
576   *
577   * Return: True if resource type is of UARTSerialBus, otherwise false.
578   */
serdev_acpi_get_uart_resource(struct acpi_resource * ares,struct acpi_resource_uart_serialbus ** uart)579  bool serdev_acpi_get_uart_resource(struct acpi_resource *ares,
580  				   struct acpi_resource_uart_serialbus **uart)
581  {
582  	struct acpi_resource_uart_serialbus *sb;
583  
584  	if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
585  		return false;
586  
587  	sb = &ares->data.uart_serial_bus;
588  	if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_UART)
589  		return false;
590  
591  	*uart = sb;
592  	return true;
593  }
594  EXPORT_SYMBOL_GPL(serdev_acpi_get_uart_resource);
595  
acpi_serdev_parse_resource(struct acpi_resource * ares,void * data)596  static int acpi_serdev_parse_resource(struct acpi_resource *ares, void *data)
597  {
598  	struct acpi_serdev_lookup *lookup = data;
599  	struct acpi_resource_uart_serialbus *sb;
600  	acpi_status status;
601  
602  	if (!serdev_acpi_get_uart_resource(ares, &sb))
603  		return 1;
604  
605  	if (lookup->index != -1 && lookup->n++ != lookup->index)
606  		return 1;
607  
608  	status = acpi_get_handle(lookup->device_handle,
609  				 sb->resource_source.string_ptr,
610  				 &lookup->controller_handle);
611  	if (ACPI_FAILURE(status))
612  		return 1;
613  
614  	/*
615  	 * NOTE: Ideally, we would also want to retrieve other properties here,
616  	 * once setting them before opening the device is supported by serdev.
617  	 */
618  
619  	return 1;
620  }
621  
acpi_serdev_do_lookup(struct acpi_device * adev,struct acpi_serdev_lookup * lookup)622  static int acpi_serdev_do_lookup(struct acpi_device *adev,
623                                   struct acpi_serdev_lookup *lookup)
624  {
625  	struct list_head resource_list;
626  	int ret;
627  
628  	lookup->device_handle = acpi_device_handle(adev);
629  	lookup->controller_handle = NULL;
630  	lookup->n = 0;
631  
632  	INIT_LIST_HEAD(&resource_list);
633  	ret = acpi_dev_get_resources(adev, &resource_list,
634  				     acpi_serdev_parse_resource, lookup);
635  	acpi_dev_free_resource_list(&resource_list);
636  
637  	if (ret < 0)
638  		return -EINVAL;
639  
640  	return 0;
641  }
642  
acpi_serdev_check_resources(struct serdev_controller * ctrl,struct acpi_device * adev)643  static int acpi_serdev_check_resources(struct serdev_controller *ctrl,
644  				       struct acpi_device *adev)
645  {
646  	struct acpi_serdev_lookup lookup;
647  	int ret;
648  
649  	if (acpi_bus_get_status(adev) || !adev->status.present)
650  		return -EINVAL;
651  
652  	/* Look for UARTSerialBusV2 resource */
653  	lookup.index = -1;	// we only care for the last device
654  
655  	ret = acpi_serdev_do_lookup(adev, &lookup);
656  	if (ret)
657  		return ret;
658  
659  	/*
660  	 * Apple machines provide an empty resource template, so on those
661  	 * machines just look for immediate children with a "baud" property
662  	 * (from the _DSM method) instead.
663  	 */
664  	if (!lookup.controller_handle && x86_apple_machine &&
665  	    !acpi_dev_get_property(adev, "baud", ACPI_TYPE_BUFFER, NULL))
666  		acpi_get_parent(adev->handle, &lookup.controller_handle);
667  
668  	/* Make sure controller and ResourceSource handle match */
669  	if (!device_match_acpi_handle(ctrl->host, lookup.controller_handle))
670  		return -ENODEV;
671  
672  	return 0;
673  }
674  
acpi_serdev_register_device(struct serdev_controller * ctrl,struct acpi_device * adev)675  static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl,
676  					       struct acpi_device *adev)
677  {
678  	struct serdev_device *serdev;
679  	int err;
680  
681  	serdev = serdev_device_alloc(ctrl);
682  	if (!serdev) {
683  		dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n",
684  			dev_name(&adev->dev));
685  		return AE_NO_MEMORY;
686  	}
687  
688  	ACPI_COMPANION_SET(&serdev->dev, adev);
689  	acpi_device_set_enumerated(adev);
690  
691  	err = serdev_device_add(serdev);
692  	if (err) {
693  		dev_err(&serdev->dev,
694  			"failure adding ACPI serdev device. status %pe\n",
695  			ERR_PTR(err));
696  		serdev_device_put(serdev);
697  	}
698  
699  	return AE_OK;
700  }
701  
702  static const struct acpi_device_id serdev_acpi_devices_blacklist[] = {
703  	{ "INT3511", 0 },
704  	{ "INT3512", 0 },
705  	{ },
706  };
707  
acpi_serdev_add_device(acpi_handle handle,u32 level,void * data,void ** return_value)708  static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level,
709  					  void *data, void **return_value)
710  {
711  	struct acpi_device *adev = acpi_fetch_acpi_dev(handle);
712  	struct serdev_controller *ctrl = data;
713  
714  	if (!adev || acpi_device_enumerated(adev))
715  		return AE_OK;
716  
717  	/* Skip if black listed */
718  	if (!acpi_match_device_ids(adev, serdev_acpi_devices_blacklist))
719  		return AE_OK;
720  
721  	if (acpi_serdev_check_resources(ctrl, adev))
722  		return AE_OK;
723  
724  	return acpi_serdev_register_device(ctrl, adev);
725  }
726  
727  
acpi_serdev_register_devices(struct serdev_controller * ctrl)728  static int acpi_serdev_register_devices(struct serdev_controller *ctrl)
729  {
730  	acpi_status status;
731  	bool skip;
732  	int ret;
733  
734  	if (!has_acpi_companion(ctrl->host))
735  		return -ENODEV;
736  
737  	/*
738  	 * Skip registration on boards where the ACPI tables are known to
739  	 * contain buggy devices. Note serdev_controller_add() must still
740  	 * succeed in this case, so that the proper serdev devices can be
741  	 * added "manually" later.
742  	 */
743  	ret = acpi_quirk_skip_serdev_enumeration(ctrl->host, &skip);
744  	if (ret)
745  		return ret;
746  	if (skip)
747  		return 0;
748  
749  	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
750  				     SERDEV_ACPI_MAX_SCAN_DEPTH,
751  				     acpi_serdev_add_device, NULL, ctrl, NULL);
752  	if (ACPI_FAILURE(status))
753  		dev_warn(&ctrl->dev, "failed to enumerate serdev slaves\n");
754  
755  	if (!ctrl->serdev)
756  		return -ENODEV;
757  
758  	return 0;
759  }
760  #else
acpi_serdev_register_devices(struct serdev_controller * ctrl)761  static inline int acpi_serdev_register_devices(struct serdev_controller *ctrl)
762  {
763  	return -ENODEV;
764  }
765  #endif /* CONFIG_ACPI */
766  
767  /**
768   * serdev_controller_add() - Add an serdev controller
769   * @ctrl:	controller to be registered.
770   *
771   * Register a controller previously allocated via serdev_controller_alloc() with
772   * the serdev core.
773   */
serdev_controller_add(struct serdev_controller * ctrl)774  int serdev_controller_add(struct serdev_controller *ctrl)
775  {
776  	int ret_of, ret_acpi, ret;
777  
778  	/* Can't register until after driver model init */
779  	if (WARN_ON(!is_registered))
780  		return -EAGAIN;
781  
782  	ret = device_add(&ctrl->dev);
783  	if (ret)
784  		return ret;
785  
786  	pm_runtime_enable(&ctrl->dev);
787  
788  	ret_of = of_serdev_register_devices(ctrl);
789  	ret_acpi = acpi_serdev_register_devices(ctrl);
790  	if (ret_of && ret_acpi) {
791  		dev_dbg(&ctrl->dev, "no devices registered: of:%pe acpi:%pe\n",
792  			ERR_PTR(ret_of), ERR_PTR(ret_acpi));
793  		ret = -ENODEV;
794  		goto err_rpm_disable;
795  	}
796  
797  	dev_dbg(&ctrl->dev, "serdev%d registered: dev:%p\n",
798  		ctrl->nr, &ctrl->dev);
799  	return 0;
800  
801  err_rpm_disable:
802  	pm_runtime_disable(&ctrl->dev);
803  	device_del(&ctrl->dev);
804  	return ret;
805  };
806  EXPORT_SYMBOL_GPL(serdev_controller_add);
807  
808  /* Remove a device associated with a controller */
serdev_remove_device(struct device * dev,void * data)809  static int serdev_remove_device(struct device *dev, void *data)
810  {
811  	struct serdev_device *serdev = to_serdev_device(dev);
812  	if (dev->type == &serdev_device_type)
813  		serdev_device_remove(serdev);
814  	return 0;
815  }
816  
817  /**
818   * serdev_controller_remove(): remove an serdev controller
819   * @ctrl:	controller to remove
820   *
821   * Remove a serdev controller.  Caller is responsible for calling
822   * serdev_controller_put() to discard the allocated controller.
823   */
serdev_controller_remove(struct serdev_controller * ctrl)824  void serdev_controller_remove(struct serdev_controller *ctrl)
825  {
826  	if (!ctrl)
827  		return;
828  
829  	device_for_each_child(&ctrl->dev, NULL, serdev_remove_device);
830  	pm_runtime_disable(&ctrl->dev);
831  	device_del(&ctrl->dev);
832  }
833  EXPORT_SYMBOL_GPL(serdev_controller_remove);
834  
835  /**
836   * __serdev_device_driver_register() - Register client driver with serdev core
837   * @sdrv:	client driver to be associated with client-device.
838   * @owner:	client driver owner to set.
839   *
840   * This API will register the client driver with the serdev framework.
841   * It is typically called from the driver's module-init function.
842   */
__serdev_device_driver_register(struct serdev_device_driver * sdrv,struct module * owner)843  int __serdev_device_driver_register(struct serdev_device_driver *sdrv, struct module *owner)
844  {
845  	sdrv->driver.bus = &serdev_bus_type;
846  	sdrv->driver.owner = owner;
847  
848  	/* force drivers to async probe so I/O is possible in probe */
849          sdrv->driver.probe_type = PROBE_PREFER_ASYNCHRONOUS;
850  
851  	return driver_register(&sdrv->driver);
852  }
853  EXPORT_SYMBOL_GPL(__serdev_device_driver_register);
854  
serdev_exit(void)855  static void __exit serdev_exit(void)
856  {
857  	bus_unregister(&serdev_bus_type);
858  	ida_destroy(&ctrl_ida);
859  }
860  module_exit(serdev_exit);
861  
serdev_init(void)862  static int __init serdev_init(void)
863  {
864  	int ret;
865  
866  	ret = bus_register(&serdev_bus_type);
867  	if (ret)
868  		return ret;
869  
870  	is_registered = true;
871  	return 0;
872  }
873  /* Must be before serial drivers register */
874  postcore_initcall(serdev_init);
875  
876  MODULE_AUTHOR("Rob Herring <robh@kernel.org>");
877  MODULE_LICENSE("GPL v2");
878  MODULE_DESCRIPTION("Serial attached device bus");
879