Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 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 | |
Jaroslav Kysela | 5049c35 | 2005-08-22 12:19:14 +0200 | [diff] [blame] | 14 | #include <linux/module.h> |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 15 | #include <linux/init.h> |
| 16 | #include <linux/device.h> |
| 17 | #include <linux/string.h> |
Mark Brown | 96841bae | 2008-12-02 15:15:50 +0000 | [diff] [blame] | 18 | #include <sound/ac97_codec.h> |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 19 | |
| 20 | /* |
Lars-Peter Clausen | 5f1d980 | 2015-07-21 21:53:00 +0200 | [diff] [blame] | 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 | |
| 82 | /* |
Nicolas Pitre | 3a91e95 | 2005-09-16 18:46:36 +0200 | [diff] [blame] | 83 | * Let drivers decide whether they want to support given codec from their |
Jeffrin Jose | d0359c6 | 2010-12-06 19:27:53 +0530 | [diff] [blame] | 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. |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 86 | */ |
| 87 | static int ac97_bus_match(struct device *dev, struct device_driver *drv) |
| 88 | { |
Nicolas Pitre | 3a91e95 | 2005-09-16 18:46:36 +0200 | [diff] [blame] | 89 | return 1; |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 90 | } |
| 91 | |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 92 | struct bus_type ac97_bus_type = { |
| 93 | .name = "ac97", |
| 94 | .match = ac97_bus_match, |
Liam Girdwood | 0ca06a0 | 2005-07-29 16:13:36 +0200 | [diff] [blame] | 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"); |