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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 * snd_ac97_check_id() - Reads and checks the vendor ID of the device
22 * @ac97: The AC97 device to check
23 * @id: The ID to compare to
24 * @id_mask: Mask that is applied to the device ID before comparing to @id
25 *
26 * If @id is 0 this function returns true if the read device vendor ID is
27 * a valid ID. If @id is non 0 this functions returns true if @id
28 * matches the read vendor ID. Otherwise the function returns false.
29 */
30static bool snd_ac97_check_id(struct snd_ac97 *ac97, unsigned int id,
31 unsigned int id_mask)
32{
33 ac97->id = ac97->bus->ops->read(ac97, AC97_VENDOR_ID1) << 16;
34 ac97->id |= ac97->bus->ops->read(ac97, AC97_VENDOR_ID2);
35
36 if (ac97->id == 0x0 || ac97->id == 0xffffffff)
37 return false;
38
39 if (id != 0 && id != (ac97->id & id_mask))
40 return false;
41
42 return true;
43}
44
45/**
46 * snd_ac97_reset() - Reset AC'97 device
47 * @ac97: The AC'97 device to reset
48 * @try_warm: Try a warm reset first
49 * @id: Expected device vendor ID
50 * @id_mask: Mask that is applied to the device ID before comparing to @id
51 *
52 * This function resets the AC'97 device. If @try_warm is true the function
53 * first performs a warm reset. If the warm reset is successful the function
54 * returns 1. Otherwise or if @try_warm is false the function issues cold reset
55 * followed by a warm reset. If this is successful the function returns 0,
56 * otherwise a negative error code. If @id is 0 any valid device ID will be
57 * accepted, otherwise only the ID that matches @id and @id_mask is accepted.
58 */
59int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,
60 unsigned int id_mask)
61{
62 struct snd_ac97_bus_ops *ops = ac97->bus->ops;
63
64 if (try_warm && ops->warm_reset) {
65 ops->warm_reset(ac97);
66 if (snd_ac97_check_id(ac97, id, id_mask))
67 return 1;
68 }
69
70 if (ops->reset)
71 ops->reset(ac97);
72 if (ops->warm_reset)
73 ops->warm_reset(ac97);
74
75 if (snd_ac97_check_id(ac97, id, id_mask))
76 return 0;
77
78 return -ENODEV;
79}
80EXPORT_SYMBOL_GPL(snd_ac97_reset);
81
82/*
83 * Let drivers decide whether they want to support given codec from their
84 * probe method. Drivers have direct access to the struct snd_ac97
85 * structure and may decide based on the id field amongst other things.
86 */
87static int ac97_bus_match(struct device *dev, struct device_driver *drv)
88{
89 return 1;
90}
91
92struct bus_type ac97_bus_type = {
93 .name = "ac97",
94 .match = ac97_bus_match,
95};
96
97static int __init ac97_bus_init(void)
98{
99 return bus_register(&ac97_bus_type);
100}
101
102subsys_initcall(ac97_bus_init);
103
104static void __exit ac97_bus_exit(void)
105{
106 bus_unregister(&ac97_bus_type);
107}
108
109module_exit(ac97_bus_exit);
110
111EXPORT_SYMBOL(ac97_bus_type);
112
113MODULE_LICENSE("GPL");
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");