projects / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 0ca06a00 LG |
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 | ||
| 5049c35b | 14 | #include <linux/module.h> |
| 0ca06a00 LG |
15 | #include <linux/init.h> |
| 16 | #include <linux/device.h> | |
| 17 | #include <linux/string.h> | |
| 96841bae | 18 | #include <sound/ac97_codec.h> |
| 0ca06a00 | 19 | |
| 5f1d980e LPC |
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 | */ | |
| 30 | static 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 | */ | |
| 59 | int 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 | } | |
| 80 | EXPORT_SYMBOL_GPL(snd_ac97_reset); | |
| 81 | ||
| 0ca06a00 | 82 | /* |
| 3a91e959 | 83 | * Let drivers decide whether they want to support given codec from their |
| d0359c6f JJ |
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. | |
| 0ca06a00 LG |
86 | */ |
| 87 | static int ac97_bus_match(struct device *dev, struct device_driver *drv) | |
| 88 | { | |
| 3a91e959 | 89 | return 1; |
| 0ca06a00 LG |
90 | } |
| 91 | ||
| 0ca06a00 LG |
92 | struct bus_type ac97_bus_type = { |
| 93 | .name = "ac97", | |
| 94 | .match = ac97_bus_match, | |
| 0ca06a00 LG |
95 | }; |
| 96 | ||
| 97 | static int __init ac97_bus_init(void) | |
| 98 | { | |
| 99 | return bus_register(&ac97_bus_type); | |
| 100 | } | |
| 101 | ||
| 102 | subsys_initcall(ac97_bus_init); | |
| 103 | ||
| 104 | static void __exit ac97_bus_exit(void) | |
| 105 | { | |
| 106 | bus_unregister(&ac97_bus_type); | |
| 107 | } | |
| 108 | ||
| 109 | module_exit(ac97_bus_exit); | |
| 110 | ||
| 111 | EXPORT_SYMBOL(ac97_bus_type); | |
| 112 | ||
| 113 | MODULE_LICENSE("GPL"); |