1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * Linux driver model AC97 bus interface
 4 *
 5 * Author:	Nicolas Pitre
 6 * Created:	Jan 14, 2005
 7 * Copyright:	(C) MontaVista Software Inc.
 
 
 
 
 
 8 */
 9
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/device.h>
13#include <linux/string.h>
14#include <sound/ac97_codec.h>
15
16/*
17 * snd_ac97_check_id() - Reads and checks the vendor ID of the device
18 * @ac97: The AC97 device to check
19 * @id: The ID to compare to
20 * @id_mask: Mask that is applied to the device ID before comparing to @id
21 *
22 * If @id is 0 this function returns true if the read device vendor ID is
23 * a valid ID. If @id is non 0 this functions returns true if @id
24 * matches the read vendor ID. Otherwise the function returns false.
25 */
26static bool snd_ac97_check_id(struct snd_ac97 *ac97, unsigned int id,
27	unsigned int id_mask)
28{
29	ac97->id = ac97->bus->ops->read(ac97, AC97_VENDOR_ID1) << 16;
30	ac97->id |= ac97->bus->ops->read(ac97, AC97_VENDOR_ID2);
31
32	if (ac97->id == 0x0 || ac97->id == 0xffffffff)
33		return false;
 
 
34
35	if (id != 0 && id != (ac97->id & id_mask))
36		return false;
37
38	return true;
39}
40
41/**
42 * snd_ac97_reset() - Reset AC'97 device
43 * @ac97: The AC'97 device to reset
44 * @try_warm: Try a warm reset first
45 * @id: Expected device vendor ID
46 * @id_mask: Mask that is applied to the device ID before comparing to @id
47 *
48 * This function resets the AC'97 device. If @try_warm is true the function
49 * first performs a warm reset. If the warm reset is successful the function
50 * returns 1. Otherwise or if @try_warm is false the function issues cold reset
51 * followed by a warm reset. If this is successful the function returns 0,
52 * otherwise a negative error code. If @id is 0 any valid device ID will be
53 * accepted, otherwise only the ID that matches @id and @id_mask is accepted.
54 */
55int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,
56	unsigned int id_mask)
57{
58	const struct snd_ac97_bus_ops *ops = ac97->bus->ops;
59
60	if (try_warm && ops->warm_reset) {
61		ops->warm_reset(ac97);
62		if (snd_ac97_check_id(ac97, id, id_mask))
63			return 1;
64	}
65
66	if (ops->reset)
67		ops->reset(ac97);
68	if (ops->warm_reset)
69		ops->warm_reset(ac97);
70
71	if (snd_ac97_check_id(ac97, id, id_mask))
72		return 0;
73
74	return -ENODEV;
75}
76EXPORT_SYMBOL_GPL(snd_ac97_reset);
77
78const struct bus_type ac97_bus_type = {
79	.name		= "ac97",
 
 
 
 
 
80};
81
82static int __init ac97_bus_init(void)
83{
84	return bus_register(&ac97_bus_type);
85}
86
87subsys_initcall(ac97_bus_init);
88
89static void __exit ac97_bus_exit(void)
90{
91	bus_unregister(&ac97_bus_type);
92}
93
94module_exit(ac97_bus_exit);
95
96EXPORT_SYMBOL(ac97_bus_type);
97
98MODULE_LICENSE("GPL");

 
 1/*
 2 * Linux driver model AC97 bus interface
 3 *
 4 * Author:	Nicolas Pitre
 5 * Created:	Jan 14, 2005
 6 * Copyright:	(C) MontaVista Software Inc.
 7 *
 8 * This program is free software; you can redistribute it and/or modify
 9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 */
13
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/device.h>
17#include <linux/string.h>
18#include <sound/ac97_codec.h>
19
20/*
21 * Let drivers decide whether they want to support given codec from their
22 * probe method. Drivers have direct access to the struct snd_ac97
23 * structure and may  decide based on the id field amongst other things.
 
 
 
 
 
24 */
25static int ac97_bus_match(struct device *dev, struct device_driver *drv)
 
26{
27	return 1;
28}
29
30#ifdef CONFIG_PM
31static int ac97_bus_suspend(struct device *dev, pm_message_t state)
32{
33	int ret = 0;
34
35	if (dev->driver && dev->driver->suspend)
36		ret = dev->driver->suspend(dev, state);
37
38	return ret;
39}
40
41static int ac97_bus_resume(struct device *dev)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
42{
43	int ret = 0;
 
 
 
 
 
 
 
 
 
 
 
44
45	if (dev->driver && dev->driver->resume)
46		ret = dev->driver->resume(dev);
47
48	return ret;
49}
50#endif /* CONFIG_PM */
51
52struct bus_type ac97_bus_type = {
53	.name		= "ac97",
54	.match		= ac97_bus_match,
55#ifdef CONFIG_PM
56	.suspend	= ac97_bus_suspend,
57	.resume		= ac97_bus_resume,
58#endif /* CONFIG_PM */
59};
60
61static int __init ac97_bus_init(void)
62{
63	return bus_register(&ac97_bus_type);
64}
65
66subsys_initcall(ac97_bus_init);
67
68static void __exit ac97_bus_exit(void)
69{
70	bus_unregister(&ac97_bus_type);
71}
72
73module_exit(ac97_bus_exit);
74
75EXPORT_SYMBOL(ac97_bus_type);
76
77MODULE_LICENSE("GPL");