127 lines
3.9 KiB
C
127 lines
3.9 KiB
C
/*
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ac97_plugin_ad1980.c Copyright (C) 2003 Red Hat, Inc. All rights reserved.
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The contents of this file are subject to the Open Software License version 1.1
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that can be found at http://www.opensource.org/licenses/osl-1.1.txt and is
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included herein by reference.
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Alternatively, the contents of this file may be used under the
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terms of the GNU General Public License version 2 (the "GPL") as
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distributed in the kernel source COPYING file, in which
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case the provisions of the GPL are applicable instead of the
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above. If you wish to allow the use of your version of this file
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only under the terms of the GPL and not to allow others to use
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your version of this file under the OSL, indicate your decision
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by deleting the provisions above and replace them with the notice
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and other provisions required by the GPL. If you do not delete
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the provisions above, a recipient may use your version of this
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file under either the OSL or the GPL.
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Authors: Alan Cox <alan@redhat.com>
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This is an example codec plugin. This one switches the connections
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around to match the setups some vendors use with audio switched to
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non standard front connectors not the normal rear ones
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This code primarily exists to demonstrate how to use the codec
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interface
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/ac97_codec.h>
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/**
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* ad1980_remove - codec remove callback
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* @codec: The codec that is being removed
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*
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* This callback occurs when an AC97 codec is being removed. A
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* codec remove call will not occur for a codec during that codec
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* probe callback.
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*
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* Most drivers will need to lock their remove versus their
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* use of the codec after the probe function.
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*/
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static void __devexit ad1980_remove(struct ac97_codec *codec, struct ac97_driver *driver)
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{
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/* Nothing to do in the simple example */
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}
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/**
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* ad1980_probe - codec found callback
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* @codec: ac97 codec matching the idents
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* @driver: ac97_driver it matched
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*
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* This entry point is called when a codec is found which matches
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* the driver. At the point it is called the codec is basically
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* operational, mixer operations have been initialised and can
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* be overriden. Called in process context. The field driver_private
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* is available for the driver to use to store stuff.
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*
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* The caller can claim the device by returning zero, or return
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* a negative error code.
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*/
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static int ad1980_probe(struct ac97_codec *codec, struct ac97_driver *driver)
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{
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u16 control;
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#define AC97_AD_MISC 0x76
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/* Switch the inputs/outputs over (from Dell code) */
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control = codec->codec_read(codec, AC97_AD_MISC);
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codec->codec_write(codec, AC97_AD_MISC, control | 0x4420);
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/* We could refuse the device since we dont need to hang around,
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but we will claim it */
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return 0;
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}
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static struct ac97_driver ad1980_driver = {
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.codec_id = 0x41445370,
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.codec_mask = 0xFFFFFFFF,
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.name = "AD1980 example",
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.probe = ad1980_probe,
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.remove = __devexit_p(ad1980_remove),
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};
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/**
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* ad1980_exit - module exit path
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*
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* Our module is being unloaded. At this point unregister_driver
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* will call back our remove handler for any existing codecs. You
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* may not unregister_driver from interrupt context or from a
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* probe/remove callback.
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*/
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static void ad1980_exit(void)
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{
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ac97_unregister_driver(&ad1980_driver);
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}
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/**
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* ad1980_init - set up ad1980 handlers
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*
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* After we call the register function it will call our probe
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* function for each existing matching device before returning to us.
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* Any devices appearing afterwards whose id's match the codec_id
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* will also cause the probe function to be called.
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* You may not register_driver from interrupt context or from a
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* probe/remove callback.
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*/
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static int ad1980_init(void)
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{
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return ac97_register_driver(&ad1980_driver);
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}
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module_init(ad1980_init);
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module_exit(ad1980_exit);
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MODULE_LICENSE("GPL");
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