projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 0ca06a00 LG |
2 | /* |
| 3 | * Linux driver model AC97 bus interface | |
| 4 | * | |
| 5 | * Author: Nicolas Pitre | |
| 6 | * Created: Jan 14, 2005 | |
| 7 | * Copyright: (C) MontaVista Software Inc. | |
| 0ca06a00 LG |
8 | */ |
| 9 | ||
| 5049c35b | 10 | #include <linux/module.h> |
| 0ca06a00 LG |
11 | #include <linux/init.h> |
| 12 | #include <linux/device.h> | |
| 13 | #include <linux/string.h> | |
| 96841bae | 14 | #include <sound/ac97_codec.h> |
| 0ca06a00 | 15 | |
| 5f1d980e LPC |
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 | */ | |
| 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 | { | |
| 19260818 | 58 | const struct snd_ac97_bus_ops *ops = ac97->bus->ops; |
| 5f1d980e LPC |
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 | ||
| 66e82d21 | 78 | const struct bus_type ac97_bus_type = { |
| 0ca06a00 | 79 | .name = "ac97", |
| 0ca06a00 LG |
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 | ||
| 92641cc5 | 98 | MODULE_DESCRIPTION("Legacy AC97 bus interface"); |
| 0ca06a00 | 99 | MODULE_LICENSE("GPL"); |