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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Linux driver model AC97 bus interface
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*
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* Author: Nicolas Pitre
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* Created: Jan 14, 2005
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* Copyright: (C) MontaVista Software Inc.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/string.h>
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#include <sound/ac97_codec.h>
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/*
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* snd_ac97_check_id() - Reads and checks the vendor ID of the device
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* @ac97: The AC97 device to check
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* @id: The ID to compare to
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* @id_mask: Mask that is applied to the device ID before comparing to @id
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*
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* If @id is 0 this function returns true if the read device vendor ID is
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* a valid ID. If @id is non 0 this functions returns true if @id
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* matches the read vendor ID. Otherwise the function returns false.
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*/
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static bool snd_ac97_check_id(struct snd_ac97 *ac97, unsigned int id,
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unsigned int id_mask)
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{
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ac97->id = ac97->bus->ops->read(ac97, AC97_VENDOR_ID1) << 16;
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ac97->id |= ac97->bus->ops->read(ac97, AC97_VENDOR_ID2);
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if (ac97->id == 0x0 || ac97->id == 0xffffffff)
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return false;
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if (id != 0 && id != (ac97->id & id_mask))
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return false;
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return true;
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}
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/**
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* snd_ac97_reset() - Reset AC'97 device
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* @ac97: The AC'97 device to reset
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* @try_warm: Try a warm reset first
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* @id: Expected device vendor ID
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* @id_mask: Mask that is applied to the device ID before comparing to @id
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*
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* This function resets the AC'97 device. If @try_warm is true the function
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* first performs a warm reset. If the warm reset is successful the function
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* returns 1. Otherwise or if @try_warm is false the function issues cold reset
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* followed by a warm reset. If this is successful the function returns 0,
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* otherwise a negative error code. If @id is 0 any valid device ID will be
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* accepted, otherwise only the ID that matches @id and @id_mask is accepted.
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*/
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int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,
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unsigned int id_mask)
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{
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struct snd_ac97_bus_ops *ops = ac97->bus->ops;
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if (try_warm && ops->warm_reset) {
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ops->warm_reset(ac97);
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if (snd_ac97_check_id(ac97, id, id_mask))
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return 1;
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}
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if (ops->reset)
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ops->reset(ac97);
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if (ops->warm_reset)
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ops->warm_reset(ac97);
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if (snd_ac97_check_id(ac97, id, id_mask))
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return 0;
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return -ENODEV;
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}
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EXPORT_SYMBOL_GPL(snd_ac97_reset);
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/*
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* Let drivers decide whether they want to support given codec from their
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* probe method. Drivers have direct access to the struct snd_ac97
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* structure and may decide based on the id field amongst other things.
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*/
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static int ac97_bus_match(struct device *dev, struct device_driver *drv)
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{
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return 1;
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}
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struct bus_type ac97_bus_type = {
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.name = "ac97",
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.match = ac97_bus_match,
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};
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static int __init ac97_bus_init(void)
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{
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return bus_register(&ac97_bus_type);
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}
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subsys_initcall(ac97_bus_init);
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static void __exit ac97_bus_exit(void)
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{
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bus_unregister(&ac97_bus_type);
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}
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module_exit(ac97_bus_exit);
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EXPORT_SYMBOL(ac97_bus_type);
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MODULE_LICENSE("GPL");
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