sound/hda/hdac_i915.c - kernel/msm-4.9 - Gitiles

 /*
  *  hdac_i915.c - routines for sync between HD-A core and i915 display driver
  *
  *  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.
  *
  *  This program is distributed in the hope that it will be useful, but
  *  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  *  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  *  for more details.
  */

 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/component.h>
 #include <drm/i915_component.h>
 #include <sound/core.h>
 #include <sound/hdaudio.h>
 #include <sound/hda_i915.h>
 #include <sound/hda_register.h>

 static struct i915_audio_component *hdac_acomp;

 /**
  * snd_hdac_set_codec_wakeup - Enable / disable HDMI/DP codec wakeup
  * @bus: HDA core bus
  * @enable: enable or disable the wakeup
  *
  * This function is supposed to be used only by a HD-audio controller
  * driver that needs the interaction with i915 graphics.
  *
  * This function should be called during the chip reset, also called at
  * resume for updating STATESTS register read.
  *
  * Returns zero for success or a negative error code.
  */
 int snd_hdac_set_codec_wakeup(struct hdac_bus *bus, bool enable)
 {
 	struct i915_audio_component *acomp = bus->audio_component;

 	if (!acomp || !acomp->ops)
 		return -ENODEV;

 	if (!acomp->ops->codec_wake_override) {
 		dev_warn(bus->dev,
 			"Invalid codec wake callback\n");
 		return 0;
 	}

 	dev_dbg(bus->dev, "%s codec wakeup\n",
 		enable ? "enable" : "disable");

 	acomp->ops->codec_wake_override(acomp->dev, enable);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_set_codec_wakeup);

 /**
  * snd_hdac_display_power - Power up / down the power refcount
  * @bus: HDA core bus
  * @enable: power up or down
  *
  * This function is supposed to be used only by a HD-audio controller
  * driver that needs the interaction with i915 graphics.
  *
  * This function manages a refcount and calls the i915 get_power() and
  * put_power() ops accordingly, toggling the codec wakeup, too.
  *
  * Returns zero for success or a negative error code.
  */
 int snd_hdac_display_power(struct hdac_bus *bus, bool enable)
 {
 	struct i915_audio_component *acomp = bus->audio_component;

 	if (!acomp || !acomp->ops)
 		return -ENODEV;

 	dev_dbg(bus->dev, "display power %s\n",
 		enable ? "enable" : "disable");

 	if (enable) {
 		if (!bus->i915_power_refcount++) {
 			acomp->ops->get_power(acomp->dev);
 			snd_hdac_set_codec_wakeup(bus, true);
 			snd_hdac_set_codec_wakeup(bus, false);
 		}
 	} else {
 		WARN_ON(!bus->i915_power_refcount);
 		if (!--bus->i915_power_refcount)
 			acomp->ops->put_power(acomp->dev);
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_display_power);

 #define CONTROLLER_IN_GPU(pci) (((pci)->device == 0x0a0c) || \
 				((pci)->device == 0x0c0c) || \
 				((pci)->device == 0x0d0c) || \
 				((pci)->device == 0x160c))

 /**
  * snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW
  * @bus: HDA core bus
  *
  * Intel HSW/BDW display HDA controller is in GPU. Both its power and link BCLK
  * depends on GPU. Two Extended Mode registers EM4 (M value) and EM5 (N Value)
  * are used to convert CDClk (Core Display Clock) to 24MHz BCLK:
  * BCLK = CDCLK * M / N
  * The values will be lost when the display power well is disabled and need to
  * be restored to avoid abnormal playback speed.
  *
  * Call this function at initializing and changing power well, as well as
  * at ELD notifier for the hotplug.
  */
 void snd_hdac_i915_set_bclk(struct hdac_bus *bus)
 {
 	struct i915_audio_component *acomp = bus->audio_component;
 	struct pci_dev *pci = to_pci_dev(bus->dev);
 	int cdclk_freq;
 	unsigned int bclk_m, bclk_n;

 	if (!acomp || !acomp->ops || !acomp->ops->get_cdclk_freq)
 		return; /* only for i915 binding */
 	if (!CONTROLLER_IN_GPU(pci))
 		return; /* only HSW/BDW */

 	cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev);
 	switch (cdclk_freq) {
 	case 337500:
 		bclk_m = 16;
 		bclk_n = 225;
 		break;

 	case 450000:
 	default: /* default CDCLK 450MHz */
 		bclk_m = 4;
 		bclk_n = 75;
 		break;

 	case 540000:
 		bclk_m = 4;
 		bclk_n = 90;
 		break;

 	case 675000:
 		bclk_m = 8;
 		bclk_n = 225;
 		break;
 	}

 	snd_hdac_chip_writew(bus, HSW_EM4, bclk_m);
 	snd_hdac_chip_writew(bus, HSW_EM5, bclk_n);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);

 /* There is a fixed mapping between audio pin node and display port.
  * on SNB, IVY, HSW, BSW, SKL, BXT, KBL:
  * Pin Widget 5 - PORT B (port = 1 in i915 driver)
  * Pin Widget 6 - PORT C (port = 2 in i915 driver)
  * Pin Widget 7 - PORT D (port = 3 in i915 driver)
  *
  * on VLV, ILK:
  * Pin Widget 4 - PORT B (port = 1 in i915 driver)
  * Pin Widget 5 - PORT C (port = 2 in i915 driver)
  * Pin Widget 6 - PORT D (port = 3 in i915 driver)
  */
 static int pin2port(struct hdac_device *codec, hda_nid_t pin_nid)
 {
 	int base_nid;

 	switch (codec->vendor_id) {
 	case 0x80860054: /* ILK */
 	case 0x80862804: /* ILK */
 	case 0x80862882: /* VLV */
 		base_nid = 3;
 		break;
 	default:
 		base_nid = 4;
 		break;
 	}

 	if (WARN_ON(pin_nid <= base_nid || pin_nid > base_nid + 3))
 		return -1;
 	return pin_nid - base_nid;
 }

 /**
  * snd_hdac_sync_audio_rate - Set N/CTS based on the sample rate
  * @codec: HDA codec
  * @nid: the pin widget NID
  * @rate: the sample rate to set
  *
  * This function is supposed to be used only by a HD-audio controller
  * driver that needs the interaction with i915 graphics.
  *
  * This function sets N/CTS value based on the given sample rate.
  * Returns zero for success, or a negative error code.
  */
 int snd_hdac_sync_audio_rate(struct hdac_device *codec, hda_nid_t nid, int rate)
 {
 	struct hdac_bus *bus = codec->bus;
 	struct i915_audio_component *acomp = bus->audio_component;
 	int port;

 	if (!acomp || !acomp->ops || !acomp->ops->sync_audio_rate)
 		return -ENODEV;
 	port = pin2port(codec, nid);
 	if (port < 0)
 		return -EINVAL;
 	return acomp->ops->sync_audio_rate(acomp->dev, port, rate);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_sync_audio_rate);

 /**
  * snd_hdac_acomp_get_eld - Get the audio state and ELD via component
  * @codec: HDA codec
  * @nid: the pin widget NID
  * @audio_enabled: the pointer to store the current audio state
  * @buffer: the buffer pointer to store ELD bytes
  * @max_bytes: the max bytes to be stored on @buffer
  *
  * This function is supposed to be used only by a HD-audio controller
  * driver that needs the interaction with i915 graphics.
  *
  * This function queries the current state of the audio on the given
  * digital port and fetches the ELD bytes onto the given buffer.
  * It returns the number of bytes for the total ELD data, zero for
  * invalid ELD, or a negative error code.
  *
  * The return size is the total bytes required for the whole ELD bytes,
  * thus it may be over @max_bytes.  If it's over @max_bytes, it implies
  * that only a part of ELD bytes have been fetched.
  */
 int snd_hdac_acomp_get_eld(struct hdac_device *codec, hda_nid_t nid,
 			   bool *audio_enabled, char *buffer, int max_bytes)
 {
 	struct hdac_bus *bus = codec->bus;
 	struct i915_audio_component *acomp = bus->audio_component;
 	int port;

 	if (!acomp || !acomp->ops || !acomp->ops->get_eld)
 		return -ENODEV;

 	port = pin2port(codec, nid);
 	if (port < 0)
 		return -EINVAL;
 	return acomp->ops->get_eld(acomp->dev, port, audio_enabled,
 				   buffer, max_bytes);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_acomp_get_eld);

 static int hdac_component_master_bind(struct device *dev)
 {
 	struct i915_audio_component *acomp = hdac_acomp;
 	int ret;

 	ret = component_bind_all(dev, acomp);
 	if (ret < 0)
 		return ret;

 	if (WARN_ON(!(acomp->dev && acomp->ops && acomp->ops->get_power &&
 		      acomp->ops->put_power && acomp->ops->get_cdclk_freq))) {
 		ret = -EINVAL;
 		goto out_unbind;
 	}

 	/*
 	 * Atm, we don't support dynamic unbinding initiated by the child
 	 * component, so pin its containing module until we unbind.
 	 */
 	if (!try_module_get(acomp->ops->owner)) {
 		ret = -ENODEV;
 		goto out_unbind;
 	}

 	return 0;

 out_unbind:
 	component_unbind_all(dev, acomp);

 	return ret;
 }

 static void hdac_component_master_unbind(struct device *dev)
 {
 	struct i915_audio_component *acomp = hdac_acomp;

 	module_put(acomp->ops->owner);
 	component_unbind_all(dev, acomp);
 	WARN_ON(acomp->ops || acomp->dev);
 }

 static const struct component_master_ops hdac_component_master_ops = {
 	.bind = hdac_component_master_bind,
 	.unbind = hdac_component_master_unbind,
 };

 static int hdac_component_master_match(struct device *dev, void *data)
 {
 	/* i915 is the only supported component */
 	return !strcmp(dev->driver->name, "i915");
 }

 /**
  * snd_hdac_i915_register_notifier - Register i915 audio component ops
  * @aops: i915 audio component ops
  *
  * This function is supposed to be used only by a HD-audio controller
  * driver that needs the interaction with i915 graphics.
  *
  * This function sets the given ops to be called by the i915 graphics driver.
  *
  * Returns zero for success or a negative error code.
  */
 int snd_hdac_i915_register_notifier(const struct i915_audio_component_audio_ops *aops)
 {
 	if (!hdac_acomp)
 		return -ENODEV;

 	hdac_acomp->audio_ops = aops;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_i915_register_notifier);

 /* check whether intel graphics is present */
 static bool i915_gfx_present(void)
 {
 	static struct pci_device_id ids[] = {
 		{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
 		  .class = PCI_BASE_CLASS_DISPLAY << 16,
 		  .class_mask = 0xff << 16 },
 		{}
 	};
 	return pci_dev_present(ids);
 }

 /**
  * snd_hdac_i915_init - Initialize i915 audio component
  * @bus: HDA core bus
  *
  * This function is supposed to be used only by a HD-audio controller
  * driver that needs the interaction with i915 graphics.
  *
  * This function initializes and sets up the audio component to communicate
  * with i915 graphics driver.
  *
  * Returns zero for success or a negative error code.
  */
 int snd_hdac_i915_init(struct hdac_bus *bus)
 {
 	struct component_match *match = NULL;
 	struct device *dev = bus->dev;
 	struct i915_audio_component *acomp;
 	int ret;

 	if (WARN_ON(hdac_acomp))
 		return -EBUSY;

 	if (!i915_gfx_present())
 		return -ENODEV;

 	acomp = kzalloc(sizeof(*acomp), GFP_KERNEL);
 	if (!acomp)
 		return -ENOMEM;
 	bus->audio_component = acomp;
 	hdac_acomp = acomp;

 	component_match_add(dev, &match, hdac_component_master_match, bus);
 	ret = component_master_add_with_match(dev, &hdac_component_master_ops,
 					      match);
 	if (ret < 0)
 		goto out_err;

 	/*
 	 * Atm, we don't support deferring the component binding, so make sure
 	 * i915 is loaded and that the binding successfully completes.
 	 */
 	request_module("i915");

 	if (!acomp->ops) {
 		ret = -ENODEV;
 		goto out_master_del;
 	}
 	dev_dbg(dev, "bound to i915 component master\n");

 	return 0;
 out_master_del:
 	component_master_del(dev, &hdac_component_master_ops);
 out_err:
 	kfree(acomp);
 	bus->audio_component = NULL;
 	hdac_acomp = NULL;
 	dev_info(dev, "failed to add i915 component master (%d)\n", ret);

 	return ret;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_i915_init);

 /**
  * snd_hdac_i915_exit - Finalize i915 audio component
  * @bus: HDA core bus
  *
  * This function is supposed to be used only by a HD-audio controller
  * driver that needs the interaction with i915 graphics.
  *
  * This function releases the i915 audio component that has been used.
  *
  * Returns zero for success or a negative error code.
  */
 int snd_hdac_i915_exit(struct hdac_bus *bus)
 {
 	struct device *dev = bus->dev;
 	struct i915_audio_component *acomp = bus->audio_component;

 	if (!acomp)
 		return 0;

 	WARN_ON(bus->i915_power_refcount);
 	if (bus->i915_power_refcount > 0 && acomp->ops)
 		acomp->ops->put_power(acomp->dev);

 	component_master_del(dev, &hdac_component_master_ops);

 	kfree(acomp);
 	bus->audio_component = NULL;
 	hdac_acomp = NULL;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_i915_exit);
	/*
	* hdac_i915.c - routines for sync between HD-A core and i915 display driver
	*
	* 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.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
	* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* for more details.
	*/

	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/pci.h>
	#include <linux/component.h>
	#include <drm/i915_component.h>
	#include <sound/core.h>
	#include <sound/hdaudio.h>
	#include <sound/hda_i915.h>
	#include <sound/hda_register.h>

	static struct i915_audio_component *hdac_acomp;

	/**
	* snd_hdac_set_codec_wakeup - Enable / disable HDMI/DP codec wakeup
	* @bus: HDA core bus
	* @enable: enable or disable the wakeup
	*
	* This function is supposed to be used only by a HD-audio controller
	* driver that needs the interaction with i915 graphics.
	*
	* This function should be called during the chip reset, also called at
	* resume for updating STATESTS register read.
	*
	* Returns zero for success or a negative error code.
	*/
	int snd_hdac_set_codec_wakeup(struct hdac_bus *bus, bool enable)
	{
	struct i915_audio_component *acomp = bus->audio_component;

	if (!acomp \|\| !acomp->ops)
	return -ENODEV;

	if (!acomp->ops->codec_wake_override) {
	dev_warn(bus->dev,
	"Invalid codec wake callback\n");
	return 0;
	}

	dev_dbg(bus->dev, "%s codec wakeup\n",
	enable ? "enable" : "disable");

	acomp->ops->codec_wake_override(acomp->dev, enable);

	return 0;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_set_codec_wakeup);

	/**
	* snd_hdac_display_power - Power up / down the power refcount
	* @bus: HDA core bus
	* @enable: power up or down
	*
	* This function is supposed to be used only by a HD-audio controller
	* driver that needs the interaction with i915 graphics.
	*
	* This function manages a refcount and calls the i915 get_power() and
	* put_power() ops accordingly, toggling the codec wakeup, too.
	*
	* Returns zero for success or a negative error code.
	*/
	int snd_hdac_display_power(struct hdac_bus *bus, bool enable)
	{
	struct i915_audio_component *acomp = bus->audio_component;

	if (!acomp \|\| !acomp->ops)
	return -ENODEV;

	dev_dbg(bus->dev, "display power %s\n",
	enable ? "enable" : "disable");

	if (enable) {
	if (!bus->i915_power_refcount++) {
	acomp->ops->get_power(acomp->dev);
	snd_hdac_set_codec_wakeup(bus, true);
	snd_hdac_set_codec_wakeup(bus, false);
	}
	} else {
	WARN_ON(!bus->i915_power_refcount);
	if (!--bus->i915_power_refcount)
	acomp->ops->put_power(acomp->dev);
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_display_power);

	#define CONTROLLER_IN_GPU(pci) (((pci)->device == 0x0a0c) \|\| \
	((pci)->device == 0x0c0c) \|\| \
	((pci)->device == 0x0d0c) \|\| \
	((pci)->device == 0x160c))

	/**
	* snd_hdac_i915_set_bclk - Reprogram BCLK for HSW/BDW
	* @bus: HDA core bus
	*
	* Intel HSW/BDW display HDA controller is in GPU. Both its power and link BCLK
	* depends on GPU. Two Extended Mode registers EM4 (M value) and EM5 (N Value)
	* are used to convert CDClk (Core Display Clock) to 24MHz BCLK:
	* BCLK = CDCLK * M / N
	* The values will be lost when the display power well is disabled and need to
	* be restored to avoid abnormal playback speed.
	*
	* Call this function at initializing and changing power well, as well as
	* at ELD notifier for the hotplug.
	*/
	void snd_hdac_i915_set_bclk(struct hdac_bus *bus)
	{
	struct i915_audio_component *acomp = bus->audio_component;
	struct pci_dev *pci = to_pci_dev(bus->dev);
	int cdclk_freq;
	unsigned int bclk_m, bclk_n;

	if (!acomp \|\| !acomp->ops \|\| !acomp->ops->get_cdclk_freq)
	return; /* only for i915 binding */
	if (!CONTROLLER_IN_GPU(pci))
	return; /* only HSW/BDW */

	cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev);
	switch (cdclk_freq) {
	case 337500:
	bclk_m = 16;
	bclk_n = 225;
	break;

	case 450000:
	default: /* default CDCLK 450MHz */
	bclk_m = 4;
	bclk_n = 75;
	break;

	case 540000:
	bclk_m = 4;
	bclk_n = 90;
	break;

	case 675000:
	bclk_m = 8;
	bclk_n = 225;
	break;
	}

	snd_hdac_chip_writew(bus, HSW_EM4, bclk_m);
	snd_hdac_chip_writew(bus, HSW_EM5, bclk_n);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);

	/* There is a fixed mapping between audio pin node and display port.
	* on SNB, IVY, HSW, BSW, SKL, BXT, KBL:
	* Pin Widget 5 - PORT B (port = 1 in i915 driver)
	* Pin Widget 6 - PORT C (port = 2 in i915 driver)
	* Pin Widget 7 - PORT D (port = 3 in i915 driver)
	*
	* on VLV, ILK:
	* Pin Widget 4 - PORT B (port = 1 in i915 driver)
	* Pin Widget 5 - PORT C (port = 2 in i915 driver)
	* Pin Widget 6 - PORT D (port = 3 in i915 driver)
	*/
	static int pin2port(struct hdac_device *codec, hda_nid_t pin_nid)
	{
	int base_nid;

	switch (codec->vendor_id) {
	case 0x80860054: /* ILK */
	case 0x80862804: /* ILK */
	case 0x80862882: /* VLV */
	base_nid = 3;
	break;
	default:
	base_nid = 4;
	break;
	}

	if (WARN_ON(pin_nid <= base_nid \|\| pin_nid > base_nid + 3))
	return -1;
	return pin_nid - base_nid;
	}

	/**
	* snd_hdac_sync_audio_rate - Set N/CTS based on the sample rate
	* @codec: HDA codec
	* @nid: the pin widget NID
	* @rate: the sample rate to set
	*
	* This function is supposed to be used only by a HD-audio controller
	* driver that needs the interaction with i915 graphics.
	*
	* This function sets N/CTS value based on the given sample rate.
	* Returns zero for success, or a negative error code.
	*/
	int snd_hdac_sync_audio_rate(struct hdac_device *codec, hda_nid_t nid, int rate)
	{
	struct hdac_bus *bus = codec->bus;
	struct i915_audio_component *acomp = bus->audio_component;
	int port;

	if (!acomp \|\| !acomp->ops \|\| !acomp->ops->sync_audio_rate)
	return -ENODEV;
	port = pin2port(codec, nid);
	if (port < 0)
	return -EINVAL;
	return acomp->ops->sync_audio_rate(acomp->dev, port, rate);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_sync_audio_rate);

	/**
	* snd_hdac_acomp_get_eld - Get the audio state and ELD via component
	* @codec: HDA codec
	* @nid: the pin widget NID
	* @audio_enabled: the pointer to store the current audio state
	* @buffer: the buffer pointer to store ELD bytes
	* @max_bytes: the max bytes to be stored on @buffer
	*
	* This function is supposed to be used only by a HD-audio controller
	* driver that needs the interaction with i915 graphics.
	*
	* This function queries the current state of the audio on the given
	* digital port and fetches the ELD bytes onto the given buffer.
	* It returns the number of bytes for the total ELD data, zero for
	* invalid ELD, or a negative error code.
	*
	* The return size is the total bytes required for the whole ELD bytes,
	* thus it may be over @max_bytes. If it's over @max_bytes, it implies
	* that only a part of ELD bytes have been fetched.
	*/
	int snd_hdac_acomp_get_eld(struct hdac_device *codec, hda_nid_t nid,
	bool audio_enabled, char buffer, int max_bytes)
	{
	struct hdac_bus *bus = codec->bus;
	struct i915_audio_component *acomp = bus->audio_component;
	int port;

	if (!acomp \|\| !acomp->ops \|\| !acomp->ops->get_eld)
	return -ENODEV;

	port = pin2port(codec, nid);
	if (port < 0)
	return -EINVAL;
	return acomp->ops->get_eld(acomp->dev, port, audio_enabled,
	buffer, max_bytes);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_acomp_get_eld);

	static int hdac_component_master_bind(struct device *dev)
	{
	struct i915_audio_component *acomp = hdac_acomp;
	int ret;

	ret = component_bind_all(dev, acomp);
	if (ret < 0)
	return ret;

	if (WARN_ON(!(acomp->dev && acomp->ops && acomp->ops->get_power &&
	acomp->ops->put_power && acomp->ops->get_cdclk_freq))) {
	ret = -EINVAL;
	goto out_unbind;
	}

	/*
	* Atm, we don't support dynamic unbinding initiated by the child
	* component, so pin its containing module until we unbind.
	*/
	if (!try_module_get(acomp->ops->owner)) {
	ret = -ENODEV;
	goto out_unbind;
	}

	return 0;

	out_unbind:
	component_unbind_all(dev, acomp);

	return ret;
	}

	static void hdac_component_master_unbind(struct device *dev)
	{
	struct i915_audio_component *acomp = hdac_acomp;

	module_put(acomp->ops->owner);
	component_unbind_all(dev, acomp);
	WARN_ON(acomp->ops \|\| acomp->dev);
	}

	static const struct component_master_ops hdac_component_master_ops = {
	.bind = hdac_component_master_bind,
	.unbind = hdac_component_master_unbind,
	};

	static int hdac_component_master_match(struct device dev, void data)
	{
	/* i915 is the only supported component */
	return !strcmp(dev->driver->name, "i915");
	}

	/**
	* snd_hdac_i915_register_notifier - Register i915 audio component ops
	* @aops: i915 audio component ops
	*
	* This function is supposed to be used only by a HD-audio controller
	* driver that needs the interaction with i915 graphics.
	*
	* This function sets the given ops to be called by the i915 graphics driver.
	*
	* Returns zero for success or a negative error code.
	*/
	int snd_hdac_i915_register_notifier(const struct i915_audio_component_audio_ops *aops)
	{
	if (!hdac_acomp)
	return -ENODEV;

	hdac_acomp->audio_ops = aops;
	return 0;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_i915_register_notifier);

	/* check whether intel graphics is present */
	static bool i915_gfx_present(void)
	{
	static struct pci_device_id ids[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
	.class = PCI_BASE_CLASS_DISPLAY << 16,
	.class_mask = 0xff << 16 },
	{}
	};
	return pci_dev_present(ids);
	}

	/**
	* snd_hdac_i915_init - Initialize i915 audio component
	* @bus: HDA core bus
	*
	* This function is supposed to be used only by a HD-audio controller
	* driver that needs the interaction with i915 graphics.
	*
	* This function initializes and sets up the audio component to communicate
	* with i915 graphics driver.
	*
	* Returns zero for success or a negative error code.
	*/
	int snd_hdac_i915_init(struct hdac_bus *bus)
	{
	struct component_match *match = NULL;
	struct device *dev = bus->dev;
	struct i915_audio_component *acomp;
	int ret;

	if (WARN_ON(hdac_acomp))
	return -EBUSY;

	if (!i915_gfx_present())
	return -ENODEV;

	acomp = kzalloc(sizeof(*acomp), GFP_KERNEL);
	if (!acomp)
	return -ENOMEM;
	bus->audio_component = acomp;
	hdac_acomp = acomp;

	component_match_add(dev, &match, hdac_component_master_match, bus);
	ret = component_master_add_with_match(dev, &hdac_component_master_ops,
	match);
	if (ret < 0)
	goto out_err;

	/*
	* Atm, we don't support deferring the component binding, so make sure
	* i915 is loaded and that the binding successfully completes.
	*/
	request_module("i915");

	if (!acomp->ops) {
	ret = -ENODEV;
	goto out_master_del;
	}
	dev_dbg(dev, "bound to i915 component master\n");

	return 0;
	out_master_del:
	component_master_del(dev, &hdac_component_master_ops);
	out_err:
	kfree(acomp);
	bus->audio_component = NULL;
	hdac_acomp = NULL;
	dev_info(dev, "failed to add i915 component master (%d)\n", ret);

	return ret;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_i915_init);

	/**
	* snd_hdac_i915_exit - Finalize i915 audio component
	* @bus: HDA core bus
	*
	* This function is supposed to be used only by a HD-audio controller
	* driver that needs the interaction with i915 graphics.
	*
	* This function releases the i915 audio component that has been used.
	*
	* Returns zero for success or a negative error code.
	*/
	int snd_hdac_i915_exit(struct hdac_bus *bus)
	{
	struct device *dev = bus->dev;
	struct i915_audio_component *acomp = bus->audio_component;

	if (!acomp)
	return 0;

	WARN_ON(bus->i915_power_refcount);
	if (bus->i915_power_refcount > 0 && acomp->ops)
	acomp->ops->put_power(acomp->dev);

	component_master_del(dev, &hdac_component_master_ops);

	kfree(acomp);
	bus->audio_component = NULL;
	hdac_acomp = NULL;

	return 0;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_i915_exit);