Thomas Gleixner | 2874c5f | 2019-05-27 08:55:01 +0200 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 2 | /* |
| 3 | * Linux driver model AC97 bus interface |
| 4 | * |
| 5 | * Author: Nicolas Pitre |
| 6 | * Created: Jan 14, 2005 |
| 7 | * Copyright: (C) MontaVista Software Inc. |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 8 | */ |
| 9 | |
Jaroslav Kysela | 5049c35 | 2005-08-22 12:19:14 +0200 | [diff] [blame] | 10 | #include <linux/module.h> |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 11 | #include <linux/init.h> |
| 12 | #include <linux/device.h> |
| 13 | #include <linux/string.h> |
Mark Brown | 96841bae | 2008-12-02 15:15:50 +0000 | [diff] [blame] | 14 | #include <sound/ac97_codec.h> |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 15 | |
| 16 | /* |
Lars-Peter Clausen | 5f1d980 | 2015-07-21 21:53:00 +0200 | [diff] [blame] | 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 | */ |
| 26 | static 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 | */ |
| 55 | int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id, |
| 56 | unsigned int id_mask) |
| 57 | { |
Takashi Iwai | 1926081 | 2020-01-03 09:16:38 +0100 | [diff] [blame] | 58 | const struct snd_ac97_bus_ops *ops = ac97->bus->ops; |
Lars-Peter Clausen | 5f1d980 | 2015-07-21 21:53:00 +0200 | [diff] [blame] | 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 | } |
| 76 | EXPORT_SYMBOL_GPL(snd_ac97_reset); |
| 77 | |
Greg Kroah-Hartman | 66e82d2 | 2023-12-19 14:34:46 +0100 | [diff] [blame] | 78 | const struct bus_type ac97_bus_type = { |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 79 | .name = "ac97", |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 80 | }; |
| 81 | |
| 82 | static int __init ac97_bus_init(void) |
| 83 | { |
| 84 | return bus_register(&ac97_bus_type); |
| 85 | } |
| 86 | |
| 87 | subsys_initcall(ac97_bus_init); |
| 88 | |
| 89 | static void __exit ac97_bus_exit(void) |
| 90 | { |
| 91 | bus_unregister(&ac97_bus_type); |
| 92 | } |
| 93 | |
| 94 | module_exit(ac97_bus_exit); |
| 95 | |
| 96 | EXPORT_SYMBOL(ac97_bus_type); |
| 97 | |
| 98 | MODULE_LICENSE("GPL"); |