99 lines
2.6 KiB
C
99 lines
2.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* Linux driver model AC97 bus interface
|
|
*
|
|
* Author: Nicolas Pitre
|
|
* Created: Jan 14, 2005
|
|
* Copyright: (C) MontaVista Software Inc.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/device.h>
|
|
#include <linux/string.h>
|
|
#include <sound/ac97_codec.h>
|
|
|
|
/*
|
|
* snd_ac97_check_id() - Reads and checks the vendor ID of the device
|
|
* @ac97: The AC97 device to check
|
|
* @id: The ID to compare to
|
|
* @id_mask: Mask that is applied to the device ID before comparing to @id
|
|
*
|
|
* If @id is 0 this function returns true if the read device vendor ID is
|
|
* a valid ID. If @id is non 0 this functions returns true if @id
|
|
* matches the read vendor ID. Otherwise the function returns false.
|
|
*/
|
|
static bool snd_ac97_check_id(struct snd_ac97 *ac97, unsigned int id,
|
|
unsigned int id_mask)
|
|
{
|
|
ac97->id = ac97->bus->ops->read(ac97, AC97_VENDOR_ID1) << 16;
|
|
ac97->id |= ac97->bus->ops->read(ac97, AC97_VENDOR_ID2);
|
|
|
|
if (ac97->id == 0x0 || ac97->id == 0xffffffff)
|
|
return false;
|
|
|
|
if (id != 0 && id != (ac97->id & id_mask))
|
|
return false;
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* snd_ac97_reset() - Reset AC'97 device
|
|
* @ac97: The AC'97 device to reset
|
|
* @try_warm: Try a warm reset first
|
|
* @id: Expected device vendor ID
|
|
* @id_mask: Mask that is applied to the device ID before comparing to @id
|
|
*
|
|
* This function resets the AC'97 device. If @try_warm is true the function
|
|
* first performs a warm reset. If the warm reset is successful the function
|
|
* returns 1. Otherwise or if @try_warm is false the function issues cold reset
|
|
* followed by a warm reset. If this is successful the function returns 0,
|
|
* otherwise a negative error code. If @id is 0 any valid device ID will be
|
|
* accepted, otherwise only the ID that matches @id and @id_mask is accepted.
|
|
*/
|
|
int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,
|
|
unsigned int id_mask)
|
|
{
|
|
const struct snd_ac97_bus_ops *ops = ac97->bus->ops;
|
|
|
|
if (try_warm && ops->warm_reset) {
|
|
ops->warm_reset(ac97);
|
|
if (snd_ac97_check_id(ac97, id, id_mask))
|
|
return 1;
|
|
}
|
|
|
|
if (ops->reset)
|
|
ops->reset(ac97);
|
|
if (ops->warm_reset)
|
|
ops->warm_reset(ac97);
|
|
|
|
if (snd_ac97_check_id(ac97, id, id_mask))
|
|
return 0;
|
|
|
|
return -ENODEV;
|
|
}
|
|
EXPORT_SYMBOL_GPL(snd_ac97_reset);
|
|
|
|
const struct bus_type ac97_bus_type = {
|
|
.name = "ac97",
|
|
};
|
|
|
|
static int __init ac97_bus_init(void)
|
|
{
|
|
return bus_register(&ac97_bus_type);
|
|
}
|
|
|
|
subsys_initcall(ac97_bus_init);
|
|
|
|
static void __exit ac97_bus_exit(void)
|
|
{
|
|
bus_unregister(&ac97_bus_type);
|
|
}
|
|
|
|
module_exit(ac97_bus_exit);
|
|
|
|
EXPORT_SYMBOL(ac97_bus_type);
|
|
|
|
MODULE_LICENSE("GPL");
|