drivers/gpu/drm/i915/intel_audio.c - kernel/msm-4.19 - Gitiles

 /*
  * Copyright © 2014 Intel Corporation
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
  */

 #include <linux/kernel.h>
 #include <linux/component.h>
 #include <drm/i915_component.h>
 #include "intel_drv.h"

 #include <drm/drmP.h>
 #include <drm/drm_edid.h>
 #include "i915_drv.h"

 /**
  * DOC: High Definition Audio over HDMI and Display Port
  *
  * The graphics and audio drivers together support High Definition Audio over
  * HDMI and Display Port. The audio programming sequences are divided into audio
  * codec and controller enable and disable sequences. The graphics driver
  * handles the audio codec sequences, while the audio driver handles the audio
  * controller sequences.
  *
  * The disable sequences must be performed before disabling the transcoder or
  * port. The enable sequences may only be performed after enabling the
  * transcoder and port, and after completed link training.
  *
  * The codec and controller sequences could be done either parallel or serial,
  * but generally the ELDV/PD change in the codec sequence indicates to the audio
  * driver that the controller sequence should start. Indeed, most of the
  * co-operation between the graphics and audio drivers is handled via audio
  * related registers. (The notable exception is the power management, not
  * covered here.)
  */

 static const struct {
 	int clock;
 	u32 config;
 } hdmi_audio_clock[] = {
 	{ DIV_ROUND_UP(25200 * 1000, 1001), AUD_CONFIG_PIXEL_CLOCK_HDMI_25175 },
 	{ 25200, AUD_CONFIG_PIXEL_CLOCK_HDMI_25200 }, /* default per bspec */
 	{ 27000, AUD_CONFIG_PIXEL_CLOCK_HDMI_27000 },
 	{ 27000 * 1001 / 1000, AUD_CONFIG_PIXEL_CLOCK_HDMI_27027 },
 	{ 54000, AUD_CONFIG_PIXEL_CLOCK_HDMI_54000 },
 	{ 54000 * 1001 / 1000, AUD_CONFIG_PIXEL_CLOCK_HDMI_54054 },
 	{ DIV_ROUND_UP(74250 * 1000, 1001), AUD_CONFIG_PIXEL_CLOCK_HDMI_74176 },
 	{ 74250, AUD_CONFIG_PIXEL_CLOCK_HDMI_74250 },
 	{ DIV_ROUND_UP(148500 * 1000, 1001), AUD_CONFIG_PIXEL_CLOCK_HDMI_148352 },
 	{ 148500, AUD_CONFIG_PIXEL_CLOCK_HDMI_148500 },
 };

 /* get AUD_CONFIG_PIXEL_CLOCK_HDMI_* value for mode */
 static u32 audio_config_hdmi_pixel_clock(struct drm_display_mode *mode)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(hdmi_audio_clock); i++) {
 		if (mode->clock == hdmi_audio_clock[i].clock)
 			break;
 	}

 	if (i == ARRAY_SIZE(hdmi_audio_clock)) {
 		DRM_DEBUG_KMS("HDMI audio pixel clock setting for %d not found, falling back to defaults\n", mode->clock);
 		i = 1;
 	}

 	DRM_DEBUG_KMS("Configuring HDMI audio for pixel clock %d (0x%08x)\n",
 		      hdmi_audio_clock[i].clock,
 		      hdmi_audio_clock[i].config);

 	return hdmi_audio_clock[i].config;
 }

 static bool intel_eld_uptodate(struct drm_connector *connector,
 			       int reg_eldv, uint32_t bits_eldv,
 			       int reg_elda, uint32_t bits_elda,
 			       int reg_edid)
 {
 	struct drm_i915_private *dev_priv = connector->dev->dev_private;
 	uint8_t *eld = connector->eld;
 	uint32_t tmp;
 	int i;

 	tmp = I915_READ(reg_eldv);
 	tmp &= bits_eldv;

 	if (!tmp)
 		return false;

 	tmp = I915_READ(reg_elda);
 	tmp &= ~bits_elda;
 	I915_WRITE(reg_elda, tmp);

 	for (i = 0; i < drm_eld_size(eld) / 4; i++)
 		if (I915_READ(reg_edid) != *((uint32_t *)eld + i))
 			return false;

 	return true;
 }

 static void g4x_audio_codec_disable(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	uint32_t eldv, tmp;

 	DRM_DEBUG_KMS("Disable audio codec\n");

 	tmp = I915_READ(G4X_AUD_VID_DID);
 	if (tmp == INTEL_AUDIO_DEVBLC || tmp == INTEL_AUDIO_DEVCL)
 		eldv = G4X_ELDV_DEVCL_DEVBLC;
 	else
 		eldv = G4X_ELDV_DEVCTG;

 	/* Invalidate ELD */
 	tmp = I915_READ(G4X_AUD_CNTL_ST);
 	tmp &= ~eldv;
 	I915_WRITE(G4X_AUD_CNTL_ST, tmp);
 }

 static void g4x_audio_codec_enable(struct drm_connector *connector,
 				   struct intel_encoder *encoder,
 				   struct drm_display_mode *mode)
 {
 	struct drm_i915_private *dev_priv = connector->dev->dev_private;
 	uint8_t *eld = connector->eld;
 	uint32_t eldv;
 	uint32_t tmp;
 	int len, i;

 	DRM_DEBUG_KMS("Enable audio codec, %u bytes ELD\n", eld[2]);

 	tmp = I915_READ(G4X_AUD_VID_DID);
 	if (tmp == INTEL_AUDIO_DEVBLC || tmp == INTEL_AUDIO_DEVCL)
 		eldv = G4X_ELDV_DEVCL_DEVBLC;
 	else
 		eldv = G4X_ELDV_DEVCTG;

 	if (intel_eld_uptodate(connector,
 			       G4X_AUD_CNTL_ST, eldv,
 			       G4X_AUD_CNTL_ST, G4X_ELD_ADDR_MASK,
 			       G4X_HDMIW_HDMIEDID))
 		return;

 	tmp = I915_READ(G4X_AUD_CNTL_ST);
 	tmp &= ~(eldv | G4X_ELD_ADDR_MASK);
 	len = (tmp >> 9) & 0x1f;		/* ELD buffer size */
 	I915_WRITE(G4X_AUD_CNTL_ST, tmp);

 	len = min(drm_eld_size(eld) / 4, len);
 	DRM_DEBUG_DRIVER("ELD size %d\n", len);
 	for (i = 0; i < len; i++)
 		I915_WRITE(G4X_HDMIW_HDMIEDID, *((uint32_t *)eld + i));

 	tmp = I915_READ(G4X_AUD_CNTL_ST);
 	tmp |= eldv;
 	I915_WRITE(G4X_AUD_CNTL_ST, tmp);
 }

 static void hsw_audio_codec_disable(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	uint32_t tmp;

 	DRM_DEBUG_KMS("Disable audio codec on pipe %c\n", pipe_name(pipe));

 	/* Disable timestamps */
 	tmp = I915_READ(HSW_AUD_CFG(pipe));
 	tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
 	tmp |= AUD_CONFIG_N_PROG_ENABLE;
 	tmp &= ~AUD_CONFIG_UPPER_N_MASK;
 	tmp &= ~AUD_CONFIG_LOWER_N_MASK;
 	if (intel_pipe_has_type(intel_crtc, INTEL_OUTPUT_DISPLAYPORT))
 		tmp |= AUD_CONFIG_N_VALUE_INDEX;
 	I915_WRITE(HSW_AUD_CFG(pipe), tmp);

 	/* Invalidate ELD */
 	tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
 	tmp &= ~AUDIO_ELD_VALID(pipe);
 	tmp &= ~AUDIO_OUTPUT_ENABLE(pipe);
 	I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);
 }

 static void hsw_audio_codec_enable(struct drm_connector *connector,
 				   struct intel_encoder *encoder,
 				   struct drm_display_mode *mode)
 {
 	struct drm_i915_private *dev_priv = connector->dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	const uint8_t *eld = connector->eld;
 	uint32_t tmp;
 	int len, i;

 	DRM_DEBUG_KMS("Enable audio codec on pipe %c, %u bytes ELD\n",
 		      pipe_name(pipe), drm_eld_size(eld));

 	/* Enable audio presence detect, invalidate ELD */
 	tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
 	tmp |= AUDIO_OUTPUT_ENABLE(pipe);
 	tmp &= ~AUDIO_ELD_VALID(pipe);
 	I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);

 	/*
 	 * FIXME: We're supposed to wait for vblank here, but we have vblanks
 	 * disabled during the mode set. The proper fix would be to push the
 	 * rest of the setup into a vblank work item, queued here, but the
 	 * infrastructure is not there yet.
 	 */

 	/* Reset ELD write address */
 	tmp = I915_READ(HSW_AUD_DIP_ELD_CTRL(pipe));
 	tmp &= ~IBX_ELD_ADDRESS_MASK;
 	I915_WRITE(HSW_AUD_DIP_ELD_CTRL(pipe), tmp);

 	/* Up to 84 bytes of hw ELD buffer */
 	len = min(drm_eld_size(eld), 84);
 	for (i = 0; i < len / 4; i++)
 		I915_WRITE(HSW_AUD_EDID_DATA(pipe), *((uint32_t *)eld + i));

 	/* ELD valid */
 	tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
 	tmp |= AUDIO_ELD_VALID(pipe);
 	I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);

 	/* Enable timestamps */
 	tmp = I915_READ(HSW_AUD_CFG(pipe));
 	tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
 	tmp &= ~AUD_CONFIG_N_PROG_ENABLE;
 	tmp &= ~AUD_CONFIG_PIXEL_CLOCK_HDMI_MASK;
 	if (intel_pipe_has_type(intel_crtc, INTEL_OUTPUT_DISPLAYPORT))
 		tmp |= AUD_CONFIG_N_VALUE_INDEX;
 	else
 		tmp |= audio_config_hdmi_pixel_clock(mode);
 	I915_WRITE(HSW_AUD_CFG(pipe), tmp);
 }

 static void ilk_audio_codec_disable(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
 	struct intel_digital_port *intel_dig_port =
 		enc_to_dig_port(&encoder->base);
 	enum port port = intel_dig_port->port;
 	enum pipe pipe = intel_crtc->pipe;
 	uint32_t tmp, eldv;
 	int aud_config;
 	int aud_cntrl_st2;

 	DRM_DEBUG_KMS("Disable audio codec on port %c, pipe %c\n",
 		      port_name(port), pipe_name(pipe));

 	if (WARN_ON(port == PORT_A))
 		return;

 	if (HAS_PCH_IBX(dev_priv->dev)) {
 		aud_config = IBX_AUD_CFG(pipe);
 		aud_cntrl_st2 = IBX_AUD_CNTL_ST2;
 	} else if (IS_VALLEYVIEW(dev_priv)) {
 		aud_config = VLV_AUD_CFG(pipe);
 		aud_cntrl_st2 = VLV_AUD_CNTL_ST2;
 	} else {
 		aud_config = CPT_AUD_CFG(pipe);
 		aud_cntrl_st2 = CPT_AUD_CNTRL_ST2;
 	}

 	/* Disable timestamps */
 	tmp = I915_READ(aud_config);
 	tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
 	tmp |= AUD_CONFIG_N_PROG_ENABLE;
 	tmp &= ~AUD_CONFIG_UPPER_N_MASK;
 	tmp &= ~AUD_CONFIG_LOWER_N_MASK;
 	if (intel_pipe_has_type(intel_crtc, INTEL_OUTPUT_DISPLAYPORT))
 		tmp |= AUD_CONFIG_N_VALUE_INDEX;
 	I915_WRITE(aud_config, tmp);

 	eldv = IBX_ELD_VALID(port);

 	/* Invalidate ELD */
 	tmp = I915_READ(aud_cntrl_st2);
 	tmp &= ~eldv;
 	I915_WRITE(aud_cntrl_st2, tmp);
 }

 static void ilk_audio_codec_enable(struct drm_connector *connector,
 				   struct intel_encoder *encoder,
 				   struct drm_display_mode *mode)
 {
 	struct drm_i915_private *dev_priv = connector->dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
 	struct intel_digital_port *intel_dig_port =
 		enc_to_dig_port(&encoder->base);
 	enum port port = intel_dig_port->port;
 	enum pipe pipe = intel_crtc->pipe;
 	uint8_t *eld = connector->eld;
 	uint32_t eldv;
 	uint32_t tmp;
 	int len, i;
 	int hdmiw_hdmiedid;
 	int aud_config;
 	int aud_cntl_st;
 	int aud_cntrl_st2;

 	DRM_DEBUG_KMS("Enable audio codec on port %c, pipe %c, %u bytes ELD\n",
 		      port_name(port), pipe_name(pipe), drm_eld_size(eld));

 	if (WARN_ON(port == PORT_A))
 		return;

 	/*
 	 * FIXME: We're supposed to wait for vblank here, but we have vblanks
 	 * disabled during the mode set. The proper fix would be to push the
 	 * rest of the setup into a vblank work item, queued here, but the
 	 * infrastructure is not there yet.
 	 */

 	if (HAS_PCH_IBX(connector->dev)) {
 		hdmiw_hdmiedid = IBX_HDMIW_HDMIEDID(pipe);
 		aud_config = IBX_AUD_CFG(pipe);
 		aud_cntl_st = IBX_AUD_CNTL_ST(pipe);
 		aud_cntrl_st2 = IBX_AUD_CNTL_ST2;
 	} else if (IS_VALLEYVIEW(connector->dev)) {
 		hdmiw_hdmiedid = VLV_HDMIW_HDMIEDID(pipe);
 		aud_config = VLV_AUD_CFG(pipe);
 		aud_cntl_st = VLV_AUD_CNTL_ST(pipe);
 		aud_cntrl_st2 = VLV_AUD_CNTL_ST2;
 	} else {
 		hdmiw_hdmiedid = CPT_HDMIW_HDMIEDID(pipe);
 		aud_config = CPT_AUD_CFG(pipe);
 		aud_cntl_st = CPT_AUD_CNTL_ST(pipe);
 		aud_cntrl_st2 = CPT_AUD_CNTRL_ST2;
 	}

 	eldv = IBX_ELD_VALID(port);

 	/* Invalidate ELD */
 	tmp = I915_READ(aud_cntrl_st2);
 	tmp &= ~eldv;
 	I915_WRITE(aud_cntrl_st2, tmp);

 	/* Reset ELD write address */
 	tmp = I915_READ(aud_cntl_st);
 	tmp &= ~IBX_ELD_ADDRESS_MASK;
 	I915_WRITE(aud_cntl_st, tmp);

 	/* Up to 84 bytes of hw ELD buffer */
 	len = min(drm_eld_size(eld), 84);
 	for (i = 0; i < len / 4; i++)
 		I915_WRITE(hdmiw_hdmiedid, *((uint32_t *)eld + i));

 	/* ELD valid */
 	tmp = I915_READ(aud_cntrl_st2);
 	tmp |= eldv;
 	I915_WRITE(aud_cntrl_st2, tmp);

 	/* Enable timestamps */
 	tmp = I915_READ(aud_config);
 	tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
 	tmp &= ~AUD_CONFIG_N_PROG_ENABLE;
 	tmp &= ~AUD_CONFIG_PIXEL_CLOCK_HDMI_MASK;
 	if (intel_pipe_has_type(intel_crtc, INTEL_OUTPUT_DISPLAYPORT))
 		tmp |= AUD_CONFIG_N_VALUE_INDEX;
 	else
 		tmp |= audio_config_hdmi_pixel_clock(mode);
 	I915_WRITE(aud_config, tmp);
 }

 /**
  * intel_audio_codec_enable - Enable the audio codec for HD audio
  * @intel_encoder: encoder on which to enable audio
  *
  * The enable sequences may only be performed after enabling the transcoder and
  * port, and after completed link training.
  */
 void intel_audio_codec_enable(struct intel_encoder *intel_encoder)
 {
 	struct drm_encoder *encoder = &intel_encoder->base;
 	struct intel_crtc *crtc = to_intel_crtc(encoder->crtc);
 	struct drm_display_mode *mode = &crtc->config->base.adjusted_mode;
 	struct drm_connector *connector;
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;

 	connector = drm_select_eld(encoder, mode);
 	if (!connector)
 		return;

 	DRM_DEBUG_DRIVER("ELD on [CONNECTOR:%d:%s], [ENCODER:%d:%s]\n",
 			 connector->base.id,
 			 connector->name,
 			 connector->encoder->base.id,
 			 connector->encoder->name);

 	/* ELD Conn_Type */
 	connector->eld[5] &= ~(3 << 2);
 	if (intel_pipe_has_type(crtc, INTEL_OUTPUT_DISPLAYPORT))
 		connector->eld[5] |= (1 << 2);

 	connector->eld[6] = drm_av_sync_delay(connector, mode) / 2;

 	if (dev_priv->display.audio_codec_enable)
 		dev_priv->display.audio_codec_enable(connector, intel_encoder, mode);
 }

 /**
  * intel_audio_codec_disable - Disable the audio codec for HD audio
  * @encoder: encoder on which to disable audio
  *
  * The disable sequences must be performed before disabling the transcoder or
  * port.
  */
 void intel_audio_codec_disable(struct intel_encoder *encoder)
 {
 	struct drm_device *dev = encoder->base.dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;

 	if (dev_priv->display.audio_codec_disable)
 		dev_priv->display.audio_codec_disable(encoder);
 }

 /**
  * intel_init_audio - Set up chip specific audio functions
  * @dev: drm device
  */
 void intel_init_audio(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;

 	if (IS_G4X(dev)) {
 		dev_priv->display.audio_codec_enable = g4x_audio_codec_enable;
 		dev_priv->display.audio_codec_disable = g4x_audio_codec_disable;
 	} else if (IS_VALLEYVIEW(dev)) {
 		dev_priv->display.audio_codec_enable = ilk_audio_codec_enable;
 		dev_priv->display.audio_codec_disable = ilk_audio_codec_disable;
 	} else if (IS_HASWELL(dev) || INTEL_INFO(dev)->gen >= 8) {
 		dev_priv->display.audio_codec_enable = hsw_audio_codec_enable;
 		dev_priv->display.audio_codec_disable = hsw_audio_codec_disable;
 	} else if (HAS_PCH_SPLIT(dev)) {
 		dev_priv->display.audio_codec_enable = ilk_audio_codec_enable;
 		dev_priv->display.audio_codec_disable = ilk_audio_codec_disable;
 	}
 }

 static void i915_audio_component_get_power(struct device *dev)
 {
 	intel_display_power_get(dev_to_i915(dev), POWER_DOMAIN_AUDIO);
 }

 static void i915_audio_component_put_power(struct device *dev)
 {
 	intel_display_power_put(dev_to_i915(dev), POWER_DOMAIN_AUDIO);
 }

 static void i915_audio_component_codec_wake_override(struct device *dev,
 						     bool enable)
 {
 	struct drm_i915_private *dev_priv = dev_to_i915(dev);
 	u32 tmp;

 	if (!IS_SKYLAKE(dev_priv))
 		return;

 	/*
 	 * Enable/disable generating the codec wake signal, overriding the
 	 * internal logic to generate the codec wake to controller.
 	 */
 	tmp = I915_READ(HSW_AUD_CHICKENBIT);
 	tmp &= ~SKL_AUD_CODEC_WAKE_SIGNAL;
 	I915_WRITE(HSW_AUD_CHICKENBIT, tmp);
 	usleep_range(1000, 1500);

 	if (enable) {
 		tmp = I915_READ(HSW_AUD_CHICKENBIT);
 		tmp |= SKL_AUD_CODEC_WAKE_SIGNAL;
 		I915_WRITE(HSW_AUD_CHICKENBIT, tmp);
 		usleep_range(1000, 1500);
 	}
 }

 /* Get CDCLK in kHz  */
 static int i915_audio_component_get_cdclk_freq(struct device *dev)
 {
 	struct drm_i915_private *dev_priv = dev_to_i915(dev);
 	int ret;

 	if (WARN_ON_ONCE(!HAS_DDI(dev_priv)))
 		return -ENODEV;

 	intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
 	ret = dev_priv->display.get_display_clock_speed(dev_priv->dev);

 	intel_display_power_put(dev_priv, POWER_DOMAIN_AUDIO);

 	return ret;
 }

 static const struct i915_audio_component_ops i915_audio_component_ops = {
 	.owner		= THIS_MODULE,
 	.get_power	= i915_audio_component_get_power,
 	.put_power	= i915_audio_component_put_power,
 	.codec_wake_override = i915_audio_component_codec_wake_override,
 	.get_cdclk_freq	= i915_audio_component_get_cdclk_freq,
 };

 static int i915_audio_component_bind(struct device *i915_dev,
 				     struct device *hda_dev, void *data)
 {
 	struct i915_audio_component *acomp = data;

 	if (WARN_ON(acomp->ops || acomp->dev))
 		return -EEXIST;

 	acomp->ops = &i915_audio_component_ops;
 	acomp->dev = i915_dev;

 	return 0;
 }

 static void i915_audio_component_unbind(struct device *i915_dev,
 					struct device *hda_dev, void *data)
 {
 	struct i915_audio_component *acomp = data;

 	acomp->ops = NULL;
 	acomp->dev = NULL;
 }

 static const struct component_ops i915_audio_component_bind_ops = {
 	.bind	= i915_audio_component_bind,
 	.unbind	= i915_audio_component_unbind,
 };

 /**
  * i915_audio_component_init - initialize and register the audio component
  * @dev_priv: i915 device instance
  *
  * This will register with the component framework a child component which
  * will bind dynamically to the snd_hda_intel driver's corresponding master
  * component when the latter is registered. During binding the child
  * initializes an instance of struct i915_audio_component which it receives
  * from the master. The master can then start to use the interface defined by
  * this struct. Each side can break the binding at any point by deregistering
  * its own component after which each side's component unbind callback is
  * called.
  *
  * We ignore any error during registration and continue with reduced
  * functionality (i.e. without HDMI audio).
  */
 void i915_audio_component_init(struct drm_i915_private *dev_priv)
 {
 	int ret;

 	ret = component_add(dev_priv->dev->dev, &i915_audio_component_bind_ops);
 	if (ret < 0) {
 		DRM_ERROR("failed to add audio component (%d)\n", ret);
 		/* continue with reduced functionality */
 		return;
 	}

 	dev_priv->audio_component_registered = true;
 }

 /**
  * i915_audio_component_cleanup - deregister the audio component
  * @dev_priv: i915 device instance
  *
  * Deregisters the audio component, breaking any existing binding to the
  * corresponding snd_hda_intel driver's master component.
  */
 void i915_audio_component_cleanup(struct drm_i915_private *dev_priv)
 {
 	if (!dev_priv->audio_component_registered)
 		return;

 	component_del(dev_priv->dev->dev, &i915_audio_component_bind_ops);
 	dev_priv->audio_component_registered = false;
 }
	/*
	* Copyright © 2014 Intel Corporation
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	* DEALINGS IN THE SOFTWARE.
	*/

	#include <linux/kernel.h>
	#include <linux/component.h>
	#include <drm/i915_component.h>
	#include "intel_drv.h"

	#include <drm/drmP.h>
	#include <drm/drm_edid.h>
	#include "i915_drv.h"

	/**
	* DOC: High Definition Audio over HDMI and Display Port
	*
	* The graphics and audio drivers together support High Definition Audio over
	* HDMI and Display Port. The audio programming sequences are divided into audio
	* codec and controller enable and disable sequences. The graphics driver
	* handles the audio codec sequences, while the audio driver handles the audio
	* controller sequences.
	*
	* The disable sequences must be performed before disabling the transcoder or
	* port. The enable sequences may only be performed after enabling the
	* transcoder and port, and after completed link training.
	*
	* The codec and controller sequences could be done either parallel or serial,
	* but generally the ELDV/PD change in the codec sequence indicates to the audio
	* driver that the controller sequence should start. Indeed, most of the
	* co-operation between the graphics and audio drivers is handled via audio
	* related registers. (The notable exception is the power management, not
	* covered here.)
	*/

	static const struct {
	int clock;
	u32 config;
	} hdmi_audio_clock[] = {
	{ DIV_ROUND_UP(25200 * 1000, 1001), AUD_CONFIG_PIXEL_CLOCK_HDMI_25175 },
	{ 25200, AUD_CONFIG_PIXEL_CLOCK_HDMI_25200 }, /* default per bspec */
	{ 27000, AUD_CONFIG_PIXEL_CLOCK_HDMI_27000 },
	{ 27000 * 1001 / 1000, AUD_CONFIG_PIXEL_CLOCK_HDMI_27027 },
	{ 54000, AUD_CONFIG_PIXEL_CLOCK_HDMI_54000 },
	{ 54000 * 1001 / 1000, AUD_CONFIG_PIXEL_CLOCK_HDMI_54054 },
	{ DIV_ROUND_UP(74250 * 1000, 1001), AUD_CONFIG_PIXEL_CLOCK_HDMI_74176 },
	{ 74250, AUD_CONFIG_PIXEL_CLOCK_HDMI_74250 },
	{ DIV_ROUND_UP(148500 * 1000, 1001), AUD_CONFIG_PIXEL_CLOCK_HDMI_148352 },
	{ 148500, AUD_CONFIG_PIXEL_CLOCK_HDMI_148500 },
	};

	/* get AUD_CONFIG_PIXEL_CLOCK_HDMI_* value for mode */
	static u32 audio_config_hdmi_pixel_clock(struct drm_display_mode *mode)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(hdmi_audio_clock); i++) {
	if (mode->clock == hdmi_audio_clock[i].clock)
	break;
	}

	if (i == ARRAY_SIZE(hdmi_audio_clock)) {
	DRM_DEBUG_KMS("HDMI audio pixel clock setting for %d not found, falling back to defaults\n", mode->clock);
	i = 1;
	}

	DRM_DEBUG_KMS("Configuring HDMI audio for pixel clock %d (0x%08x)\n",
	hdmi_audio_clock[i].clock,
	hdmi_audio_clock[i].config);

	return hdmi_audio_clock[i].config;
	}

	static bool intel_eld_uptodate(struct drm_connector *connector,
	int reg_eldv, uint32_t bits_eldv,
	int reg_elda, uint32_t bits_elda,
	int reg_edid)
	{
	struct drm_i915_private *dev_priv = connector->dev->dev_private;
	uint8_t *eld = connector->eld;
	uint32_t tmp;
	int i;

	tmp = I915_READ(reg_eldv);
	tmp &= bits_eldv;

	if (!tmp)
	return false;

	tmp = I915_READ(reg_elda);
	tmp &= ~bits_elda;
	I915_WRITE(reg_elda, tmp);

	for (i = 0; i < drm_eld_size(eld) / 4; i++)
	if (I915_READ(reg_edid) != ((uint32_t )eld + i))
	return false;

	return true;
	}

	static void g4x_audio_codec_disable(struct intel_encoder *encoder)
	{
	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
	uint32_t eldv, tmp;

	DRM_DEBUG_KMS("Disable audio codec\n");

	tmp = I915_READ(G4X_AUD_VID_DID);
	if (tmp == INTEL_AUDIO_DEVBLC \|\| tmp == INTEL_AUDIO_DEVCL)
	eldv = G4X_ELDV_DEVCL_DEVBLC;
	else
	eldv = G4X_ELDV_DEVCTG;

	/* Invalidate ELD */
	tmp = I915_READ(G4X_AUD_CNTL_ST);
	tmp &= ~eldv;
	I915_WRITE(G4X_AUD_CNTL_ST, tmp);
	}

	static void g4x_audio_codec_enable(struct drm_connector *connector,
	struct intel_encoder *encoder,
	struct drm_display_mode *mode)
	{
	struct drm_i915_private *dev_priv = connector->dev->dev_private;
	uint8_t *eld = connector->eld;
	uint32_t eldv;
	uint32_t tmp;
	int len, i;

	DRM_DEBUG_KMS("Enable audio codec, %u bytes ELD\n", eld[2]);

	tmp = I915_READ(G4X_AUD_VID_DID);
	if (tmp == INTEL_AUDIO_DEVBLC \|\| tmp == INTEL_AUDIO_DEVCL)
	eldv = G4X_ELDV_DEVCL_DEVBLC;
	else
	eldv = G4X_ELDV_DEVCTG;

	if (intel_eld_uptodate(connector,
	G4X_AUD_CNTL_ST, eldv,
	G4X_AUD_CNTL_ST, G4X_ELD_ADDR_MASK,
	G4X_HDMIW_HDMIEDID))
	return;

	tmp = I915_READ(G4X_AUD_CNTL_ST);
	tmp &= ~(eldv \| G4X_ELD_ADDR_MASK);
	len = (tmp >> 9) & 0x1f; /* ELD buffer size */
	I915_WRITE(G4X_AUD_CNTL_ST, tmp);

	len = min(drm_eld_size(eld) / 4, len);
	DRM_DEBUG_DRIVER("ELD size %d\n", len);
	for (i = 0; i < len; i++)
	I915_WRITE(G4X_HDMIW_HDMIEDID, ((uint32_t )eld + i));

	tmp = I915_READ(G4X_AUD_CNTL_ST);
	tmp \|= eldv;
	I915_WRITE(G4X_AUD_CNTL_ST, tmp);
	}

	static void hsw_audio_codec_disable(struct intel_encoder *encoder)
	{
	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
	enum pipe pipe = intel_crtc->pipe;
	uint32_t tmp;

	DRM_DEBUG_KMS("Disable audio codec on pipe %c\n", pipe_name(pipe));

	/* Disable timestamps */
	tmp = I915_READ(HSW_AUD_CFG(pipe));
	tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
	tmp \|= AUD_CONFIG_N_PROG_ENABLE;
	tmp &= ~AUD_CONFIG_UPPER_N_MASK;
	tmp &= ~AUD_CONFIG_LOWER_N_MASK;
	if (intel_pipe_has_type(intel_crtc, INTEL_OUTPUT_DISPLAYPORT))
	tmp \|= AUD_CONFIG_N_VALUE_INDEX;
	I915_WRITE(HSW_AUD_CFG(pipe), tmp);

	/* Invalidate ELD */
	tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
	tmp &= ~AUDIO_ELD_VALID(pipe);
	tmp &= ~AUDIO_OUTPUT_ENABLE(pipe);
	I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);
	}

	static void hsw_audio_codec_enable(struct drm_connector *connector,
	struct intel_encoder *encoder,
	struct drm_display_mode *mode)
	{
	struct drm_i915_private *dev_priv = connector->dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
	enum pipe pipe = intel_crtc->pipe;
	const uint8_t *eld = connector->eld;
	uint32_t tmp;
	int len, i;

	DRM_DEBUG_KMS("Enable audio codec on pipe %c, %u bytes ELD\n",
	pipe_name(pipe), drm_eld_size(eld));

	/* Enable audio presence detect, invalidate ELD */
	tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
	tmp \|= AUDIO_OUTPUT_ENABLE(pipe);
	tmp &= ~AUDIO_ELD_VALID(pipe);
	I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);

	/*
	* FIXME: We're supposed to wait for vblank here, but we have vblanks
	* disabled during the mode set. The proper fix would be to push the
	* rest of the setup into a vblank work item, queued here, but the
	* infrastructure is not there yet.
	*/

	/* Reset ELD write address */
	tmp = I915_READ(HSW_AUD_DIP_ELD_CTRL(pipe));
	tmp &= ~IBX_ELD_ADDRESS_MASK;
	I915_WRITE(HSW_AUD_DIP_ELD_CTRL(pipe), tmp);

	/* Up to 84 bytes of hw ELD buffer */
	len = min(drm_eld_size(eld), 84);
	for (i = 0; i < len / 4; i++)
	I915_WRITE(HSW_AUD_EDID_DATA(pipe), ((uint32_t )eld + i));

	/* ELD valid */
	tmp = I915_READ(HSW_AUD_PIN_ELD_CP_VLD);
	tmp \|= AUDIO_ELD_VALID(pipe);
	I915_WRITE(HSW_AUD_PIN_ELD_CP_VLD, tmp);

	/* Enable timestamps */
	tmp = I915_READ(HSW_AUD_CFG(pipe));
	tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
	tmp &= ~AUD_CONFIG_N_PROG_ENABLE;
	tmp &= ~AUD_CONFIG_PIXEL_CLOCK_HDMI_MASK;
	if (intel_pipe_has_type(intel_crtc, INTEL_OUTPUT_DISPLAYPORT))
	tmp \|= AUD_CONFIG_N_VALUE_INDEX;
	else
	tmp \|= audio_config_hdmi_pixel_clock(mode);
	I915_WRITE(HSW_AUD_CFG(pipe), tmp);
	}

	static void ilk_audio_codec_disable(struct intel_encoder *encoder)
	{
	struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
	struct intel_digital_port *intel_dig_port =
	enc_to_dig_port(&encoder->base);
	enum port port = intel_dig_port->port;
	enum pipe pipe = intel_crtc->pipe;
	uint32_t tmp, eldv;
	int aud_config;
	int aud_cntrl_st2;

	DRM_DEBUG_KMS("Disable audio codec on port %c, pipe %c\n",
	port_name(port), pipe_name(pipe));

	if (WARN_ON(port == PORT_A))
	return;

	if (HAS_PCH_IBX(dev_priv->dev)) {
	aud_config = IBX_AUD_CFG(pipe);
	aud_cntrl_st2 = IBX_AUD_CNTL_ST2;
	} else if (IS_VALLEYVIEW(dev_priv)) {
	aud_config = VLV_AUD_CFG(pipe);
	aud_cntrl_st2 = VLV_AUD_CNTL_ST2;
	} else {
	aud_config = CPT_AUD_CFG(pipe);
	aud_cntrl_st2 = CPT_AUD_CNTRL_ST2;
	}

	/* Disable timestamps */
	tmp = I915_READ(aud_config);
	tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
	tmp \|= AUD_CONFIG_N_PROG_ENABLE;
	tmp &= ~AUD_CONFIG_UPPER_N_MASK;
	tmp &= ~AUD_CONFIG_LOWER_N_MASK;
	if (intel_pipe_has_type(intel_crtc, INTEL_OUTPUT_DISPLAYPORT))
	tmp \|= AUD_CONFIG_N_VALUE_INDEX;
	I915_WRITE(aud_config, tmp);

	eldv = IBX_ELD_VALID(port);

	/* Invalidate ELD */
	tmp = I915_READ(aud_cntrl_st2);
	tmp &= ~eldv;
	I915_WRITE(aud_cntrl_st2, tmp);
	}

	static void ilk_audio_codec_enable(struct drm_connector *connector,
	struct intel_encoder *encoder,
	struct drm_display_mode *mode)
	{
	struct drm_i915_private *dev_priv = connector->dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
	struct intel_digital_port *intel_dig_port =
	enc_to_dig_port(&encoder->base);
	enum port port = intel_dig_port->port;
	enum pipe pipe = intel_crtc->pipe;
	uint8_t *eld = connector->eld;
	uint32_t eldv;
	uint32_t tmp;
	int len, i;
	int hdmiw_hdmiedid;
	int aud_config;
	int aud_cntl_st;
	int aud_cntrl_st2;

	DRM_DEBUG_KMS("Enable audio codec on port %c, pipe %c, %u bytes ELD\n",
	port_name(port), pipe_name(pipe), drm_eld_size(eld));

	if (WARN_ON(port == PORT_A))
	return;

	/*
	* FIXME: We're supposed to wait for vblank here, but we have vblanks
	* disabled during the mode set. The proper fix would be to push the
	* rest of the setup into a vblank work item, queued here, but the
	* infrastructure is not there yet.
	*/

	if (HAS_PCH_IBX(connector->dev)) {
	hdmiw_hdmiedid = IBX_HDMIW_HDMIEDID(pipe);
	aud_config = IBX_AUD_CFG(pipe);
	aud_cntl_st = IBX_AUD_CNTL_ST(pipe);
	aud_cntrl_st2 = IBX_AUD_CNTL_ST2;
	} else if (IS_VALLEYVIEW(connector->dev)) {
	hdmiw_hdmiedid = VLV_HDMIW_HDMIEDID(pipe);
	aud_config = VLV_AUD_CFG(pipe);
	aud_cntl_st = VLV_AUD_CNTL_ST(pipe);
	aud_cntrl_st2 = VLV_AUD_CNTL_ST2;
	} else {
	hdmiw_hdmiedid = CPT_HDMIW_HDMIEDID(pipe);
	aud_config = CPT_AUD_CFG(pipe);
	aud_cntl_st = CPT_AUD_CNTL_ST(pipe);
	aud_cntrl_st2 = CPT_AUD_CNTRL_ST2;
	}

	eldv = IBX_ELD_VALID(port);

	/* Invalidate ELD */
	tmp = I915_READ(aud_cntrl_st2);
	tmp &= ~eldv;
	I915_WRITE(aud_cntrl_st2, tmp);

	/* Reset ELD write address */
	tmp = I915_READ(aud_cntl_st);
	tmp &= ~IBX_ELD_ADDRESS_MASK;
	I915_WRITE(aud_cntl_st, tmp);

	/* Up to 84 bytes of hw ELD buffer */
	len = min(drm_eld_size(eld), 84);
	for (i = 0; i < len / 4; i++)
	I915_WRITE(hdmiw_hdmiedid, ((uint32_t )eld + i));

	/* ELD valid */
	tmp = I915_READ(aud_cntrl_st2);
	tmp \|= eldv;
	I915_WRITE(aud_cntrl_st2, tmp);

	/* Enable timestamps */
	tmp = I915_READ(aud_config);
	tmp &= ~AUD_CONFIG_N_VALUE_INDEX;
	tmp &= ~AUD_CONFIG_N_PROG_ENABLE;
	tmp &= ~AUD_CONFIG_PIXEL_CLOCK_HDMI_MASK;
	if (intel_pipe_has_type(intel_crtc, INTEL_OUTPUT_DISPLAYPORT))
	tmp \|= AUD_CONFIG_N_VALUE_INDEX;
	else
	tmp \|= audio_config_hdmi_pixel_clock(mode);
	I915_WRITE(aud_config, tmp);
	}

	/**
	* intel_audio_codec_enable - Enable the audio codec for HD audio
	* @intel_encoder: encoder on which to enable audio
	*
	* The enable sequences may only be performed after enabling the transcoder and
	* port, and after completed link training.
	*/
	void intel_audio_codec_enable(struct intel_encoder *intel_encoder)
	{
	struct drm_encoder *encoder = &intel_encoder->base;
	struct intel_crtc *crtc = to_intel_crtc(encoder->crtc);
	struct drm_display_mode *mode = &crtc->config->base.adjusted_mode;
	struct drm_connector *connector;
	struct drm_device *dev = encoder->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;

	connector = drm_select_eld(encoder, mode);
	if (!connector)
	return;

	DRM_DEBUG_DRIVER("ELD on [CONNECTOR:%d:%s], [ENCODER:%d:%s]\n",
	connector->base.id,
	connector->name,
	connector->encoder->base.id,
	connector->encoder->name);

	/* ELD Conn_Type */
	connector->eld[5] &= ~(3 << 2);
	if (intel_pipe_has_type(crtc, INTEL_OUTPUT_DISPLAYPORT))
	connector->eld[5] \|= (1 << 2);

	connector->eld[6] = drm_av_sync_delay(connector, mode) / 2;

	if (dev_priv->display.audio_codec_enable)
	dev_priv->display.audio_codec_enable(connector, intel_encoder, mode);
	}

	/**
	* intel_audio_codec_disable - Disable the audio codec for HD audio
	* @encoder: encoder on which to disable audio
	*
	* The disable sequences must be performed before disabling the transcoder or
	* port.
	*/
	void intel_audio_codec_disable(struct intel_encoder *encoder)
	{
	struct drm_device *dev = encoder->base.dev;
	struct drm_i915_private *dev_priv = dev->dev_private;

	if (dev_priv->display.audio_codec_disable)
	dev_priv->display.audio_codec_disable(encoder);
	}

	/**
	* intel_init_audio - Set up chip specific audio functions
	* @dev: drm device
	*/
	void intel_init_audio(struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;

	if (IS_G4X(dev)) {
	dev_priv->display.audio_codec_enable = g4x_audio_codec_enable;
	dev_priv->display.audio_codec_disable = g4x_audio_codec_disable;
	} else if (IS_VALLEYVIEW(dev)) {
	dev_priv->display.audio_codec_enable = ilk_audio_codec_enable;
	dev_priv->display.audio_codec_disable = ilk_audio_codec_disable;
	} else if (IS_HASWELL(dev) \|\| INTEL_INFO(dev)->gen >= 8) {
	dev_priv->display.audio_codec_enable = hsw_audio_codec_enable;
	dev_priv->display.audio_codec_disable = hsw_audio_codec_disable;
	} else if (HAS_PCH_SPLIT(dev)) {
	dev_priv->display.audio_codec_enable = ilk_audio_codec_enable;
	dev_priv->display.audio_codec_disable = ilk_audio_codec_disable;
	}
	}

	static void i915_audio_component_get_power(struct device *dev)
	{
	intel_display_power_get(dev_to_i915(dev), POWER_DOMAIN_AUDIO);
	}

	static void i915_audio_component_put_power(struct device *dev)
	{
	intel_display_power_put(dev_to_i915(dev), POWER_DOMAIN_AUDIO);
	}

	static void i915_audio_component_codec_wake_override(struct device *dev,
	bool enable)
	{
	struct drm_i915_private *dev_priv = dev_to_i915(dev);
	u32 tmp;

	if (!IS_SKYLAKE(dev_priv))
	return;

	/*
	* Enable/disable generating the codec wake signal, overriding the
	* internal logic to generate the codec wake to controller.
	*/
	tmp = I915_READ(HSW_AUD_CHICKENBIT);
	tmp &= ~SKL_AUD_CODEC_WAKE_SIGNAL;
	I915_WRITE(HSW_AUD_CHICKENBIT, tmp);
	usleep_range(1000, 1500);

	if (enable) {
	tmp = I915_READ(HSW_AUD_CHICKENBIT);
	tmp \|= SKL_AUD_CODEC_WAKE_SIGNAL;
	I915_WRITE(HSW_AUD_CHICKENBIT, tmp);
	usleep_range(1000, 1500);
	}
	}

	/* Get CDCLK in kHz */
	static int i915_audio_component_get_cdclk_freq(struct device *dev)
	{
	struct drm_i915_private *dev_priv = dev_to_i915(dev);
	int ret;

	if (WARN_ON_ONCE(!HAS_DDI(dev_priv)))
	return -ENODEV;

	intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
	ret = dev_priv->display.get_display_clock_speed(dev_priv->dev);

	intel_display_power_put(dev_priv, POWER_DOMAIN_AUDIO);

	return ret;
	}

	static const struct i915_audio_component_ops i915_audio_component_ops = {
	.owner = THIS_MODULE,
	.get_power = i915_audio_component_get_power,
	.put_power = i915_audio_component_put_power,
	.codec_wake_override = i915_audio_component_codec_wake_override,
	.get_cdclk_freq = i915_audio_component_get_cdclk_freq,
	};

	static int i915_audio_component_bind(struct device *i915_dev,
	struct device hda_dev, void data)
	{
	struct i915_audio_component *acomp = data;

	if (WARN_ON(acomp->ops \|\| acomp->dev))
	return -EEXIST;

	acomp->ops = &i915_audio_component_ops;
	acomp->dev = i915_dev;

	return 0;
	}

	static void i915_audio_component_unbind(struct device *i915_dev,
	struct device hda_dev, void data)
	{
	struct i915_audio_component *acomp = data;

	acomp->ops = NULL;
	acomp->dev = NULL;
	}

	static const struct component_ops i915_audio_component_bind_ops = {
	.bind = i915_audio_component_bind,
	.unbind = i915_audio_component_unbind,
	};

	/**
	* i915_audio_component_init - initialize and register the audio component
	* @dev_priv: i915 device instance
	*
	* This will register with the component framework a child component which
	* will bind dynamically to the snd_hda_intel driver's corresponding master
	* component when the latter is registered. During binding the child
	* initializes an instance of struct i915_audio_component which it receives
	* from the master. The master can then start to use the interface defined by
	* this struct. Each side can break the binding at any point by deregistering
	* its own component after which each side's component unbind callback is
	* called.
	*
	* We ignore any error during registration and continue with reduced
	* functionality (i.e. without HDMI audio).
	*/
	void i915_audio_component_init(struct drm_i915_private *dev_priv)
	{
	int ret;

	ret = component_add(dev_priv->dev->dev, &i915_audio_component_bind_ops);
	if (ret < 0) {
	DRM_ERROR("failed to add audio component (%d)\n", ret);
	/* continue with reduced functionality */
	return;
	}

	dev_priv->audio_component_registered = true;
	}

	/**
	* i915_audio_component_cleanup - deregister the audio component
	* @dev_priv: i915 device instance
	*
	* Deregisters the audio component, breaking any existing binding to the
	* corresponding snd_hda_intel driver's master component.
	*/
	void i915_audio_component_cleanup(struct drm_i915_private *dev_priv)
	{
	if (!dev_priv->audio_component_registered)
	return;

	component_del(dev_priv->dev->dev, &i915_audio_component_bind_ops);
	dev_priv->audio_component_registered = false;
	}