Message-Id: <20241223-drm-bridge-hdmi-connector-v9-3-6ce16bcedb8b@linaro.org>
Date: Mon, 23 Dec 2024 04:58:54 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Andrzej Hajda <andrzej.hajda@...el.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>, 
 Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>, 
 Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>, 
 Phong LE <ple@...libre.com>, Inki Dae <inki.dae@...sung.com>, 
 Seung-Woo Kim <sw0312.kim@...sung.com>, 
 Kyungmin Park <kyungmin.park@...sung.com>, 
 Krzysztof Kozlowski <krzk@...nel.org>, 
 Alim Akhtar <alim.akhtar@...sung.com>, Russell King <linux@...linux.org.uk>, 
 Chun-Kuang Hu <chunkuang.hu@...nel.org>, 
 Philipp Zabel <p.zabel@...gutronix.de>, 
 Matthias Brugger <matthias.bgg@...il.com>, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
 Sandy Huang <hjc@...k-chips.com>, 
 Heiko Stübner <heiko@...ech.de>, 
 Andy Yan <andy.yan@...k-chips.com>, Alain Volmat <alain.volmat@...s.st.com>, 
 Raphael Gallais-Pou <rgallaispou@...il.com>, 
 Dave Stevenson <dave.stevenson@...pberrypi.com>, 
 Maíra Canal <mcanal@...lia.com>, 
 Raspberry Pi Kernel Maintenance <kernel-list@...pberrypi.com>
Cc: Jani Nikula <jani.nikula@...ux.intel.com>, 
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 linux-sound@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
 linux-samsung-soc@...r.kernel.org, linux-mediatek@...ts.infradead.org, 
 linux-rockchip@...ts.infradead.org
Subject: [PATCH v9 03/10] drm/connector: implement generic HDMI audio
 helpers

Several DRM drivers implement HDMI codec support (despite its name it
applies to both HDMI and DisplayPort drivers). Implement generic
framework to be used by these drivers. This removes a requirement to
implement get_eld() callback and provides default implementation for
codec's plug handling.

Acked-by: Maxime Ripard <mripard@...nel.org>
Tested-by: Dave Stevenson <dave.stevenson@...pberrypi.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
 drivers/gpu/drm/display/Kconfig                 |   6 +
 drivers/gpu/drm/display/Makefile                |   2 +
 drivers/gpu/drm/display/drm_hdmi_audio_helper.c | 189 ++++++++++++++++++++++++
 drivers/gpu/drm/drm_connector.c                 |   5 +
 include/drm/drm_connector.h                     | 125 ++++++++++++++++
 5 files changed, 327 insertions(+)

diff --git a/drivers/gpu/drm/display/Kconfig b/drivers/gpu/drm/display/Kconfig
index 6a4e892afcf8966b45f50ce1f2530707441eda51..80c1953cac14a088d764acd45df03debfcb95e7c 100644
--- a/drivers/gpu/drm/display/Kconfig
+++ b/drivers/gpu/drm/display/Kconfig
@@ -75,6 +75,12 @@ config DRM_DISPLAY_HDCP_HELPER
 	help
 	  DRM display helpers for HDCP.
 
+config DRM_DISPLAY_HDMI_AUDIO_HELPER
+	bool
+	help
+	  DRM display helpers for HDMI Audio functionality (generic HDMI Codec
+	  implementation).
+
 config DRM_DISPLAY_HDMI_HELPER
 	bool
 	help
diff --git a/drivers/gpu/drm/display/Makefile b/drivers/gpu/drm/display/Makefile
index 629c834c3192c61ab8e071223c6a08b98d295b0c..b17879b957d5401721396e247fa346387cf6c48a 100644
--- a/drivers/gpu/drm/display/Makefile
+++ b/drivers/gpu/drm/display/Makefile
@@ -14,6 +14,8 @@ drm_display_helper-$(CONFIG_DRM_DISPLAY_DP_TUNNEL) += \
 drm_display_helper-$(CONFIG_DRM_DISPLAY_DSC_HELPER) += \
 	drm_dsc_helper.o
 drm_display_helper-$(CONFIG_DRM_DISPLAY_HDCP_HELPER) += drm_hdcp_helper.o
+drm_display_helper-$(CONFIG_DRM_DISPLAY_HDMI_AUDIO_HELPER) += \
+	drm_hdmi_audio_helper.o
 drm_display_helper-$(CONFIG_DRM_DISPLAY_HDMI_HELPER) += \
 	drm_hdmi_helper.o \
 	drm_scdc_helper.o
diff --git a/drivers/gpu/drm/display/drm_hdmi_audio_helper.c b/drivers/gpu/drm/display/drm_hdmi_audio_helper.c
new file mode 100644
index 0000000000000000000000000000000000000000..cda9403e49ec35e9d9c118705934908b3ca925b0
--- /dev/null
+++ b/drivers/gpu/drm/display/drm_hdmi_audio_helper.c
@@ -0,0 +1,189 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright (c) 2024 Linaro Ltd
+ */
+
+#include <linux/mutex.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+
+#include <drm/drm_connector.h>
+#include <drm/drm_device.h>
+
+#include <sound/hdmi-codec.h>
+
+static int drm_connector_hdmi_audio_startup(struct device *dev, void *data)
+{
+	struct drm_connector *connector = data;
+	const struct drm_connector_hdmi_audio_funcs *funcs =
+		connector->hdmi_audio.funcs;
+
+	if (funcs->startup)
+		return funcs->startup(connector);
+
+	return 0;
+}
+
+static int drm_connector_hdmi_audio_prepare(struct device *dev, void *data,
+					    struct hdmi_codec_daifmt *fmt,
+					    struct hdmi_codec_params *hparms)
+{
+	struct drm_connector *connector = data;
+	const struct drm_connector_hdmi_audio_funcs *funcs =
+		connector->hdmi_audio.funcs;
+
+	return funcs->prepare(connector, fmt, hparms);
+}
+
+static void drm_connector_hdmi_audio_shutdown(struct device *dev, void *data)
+{
+	struct drm_connector *connector = data;
+	const struct drm_connector_hdmi_audio_funcs *funcs =
+		connector->hdmi_audio.funcs;
+
+	return funcs->shutdown(connector);
+}
+
+static int drm_connector_hdmi_audio_mute_stream(struct device *dev, void *data,
+						bool enable, int direction)
+{
+	struct drm_connector *connector = data;
+	const struct drm_connector_hdmi_audio_funcs *funcs =
+		connector->hdmi_audio.funcs;
+
+	if (funcs->mute_stream)
+		return funcs->mute_stream(connector, enable, direction);
+
+	return -ENOTSUPP;
+}
+
+static int drm_connector_hdmi_audio_get_dai_id(struct snd_soc_component *comment,
+					       struct device_node *endpoint,
+					       void *data)
+{
+	struct drm_connector *connector = data;
+	struct of_endpoint of_ep;
+	int ret;
+
+	if (connector->hdmi_audio.dai_port < 0)
+		return -ENOTSUPP;
+
+	ret = of_graph_parse_endpoint(endpoint, &of_ep);
+	if (ret < 0)
+		return ret;
+
+	if (of_ep.port == connector->hdmi_audio.dai_port)
+		return 0;
+
+	return -EINVAL;
+}
+
+static int drm_connector_hdmi_audio_get_eld(struct device *dev, void *data,
+					    uint8_t *buf, size_t len)
+{
+	struct drm_connector *connector = data;
+
+	mutex_lock(&connector->eld_mutex);
+	memcpy(buf, connector->eld, min(sizeof(connector->eld), len));
+	mutex_unlock(&connector->eld_mutex);
+
+	return 0;
+}
+
+static int drm_connector_hdmi_audio_hook_plugged_cb(struct device *dev,
+						    void *data,
+						    hdmi_codec_plugged_cb fn,
+						    struct device *codec_dev)
+{
+	struct drm_connector *connector = data;
+
+	mutex_lock(&connector->hdmi_audio.lock);
+
+	connector->hdmi_audio.plugged_cb = fn;
+	connector->hdmi_audio.plugged_cb_dev = codec_dev;
+
+	fn(codec_dev, connector->hdmi_audio.last_state);
+
+	mutex_unlock(&connector->hdmi_audio.lock);
+
+	return 0;
+}
+
+void drm_connector_hdmi_audio_plugged_notify(struct drm_connector *connector,
+					     bool plugged)
+{
+	mutex_lock(&connector->hdmi_audio.lock);
+
+	connector->hdmi_audio.last_state = plugged;
+
+	if (connector->hdmi_audio.plugged_cb &&
+	    connector->hdmi_audio.plugged_cb_dev)
+		connector->hdmi_audio.plugged_cb(connector->hdmi_audio.plugged_cb_dev,
+						 connector->hdmi_audio.last_state);
+
+	mutex_unlock(&connector->hdmi_audio.lock);
+}
+EXPORT_SYMBOL(drm_connector_hdmi_audio_plugged_notify);
+
+static const struct hdmi_codec_ops drm_connector_hdmi_audio_ops = {
+	.audio_startup = drm_connector_hdmi_audio_startup,
+	.prepare = drm_connector_hdmi_audio_prepare,
+	.audio_shutdown = drm_connector_hdmi_audio_shutdown,
+	.mute_stream = drm_connector_hdmi_audio_mute_stream,
+	.get_eld = drm_connector_hdmi_audio_get_eld,
+	.get_dai_id = drm_connector_hdmi_audio_get_dai_id,
+	.hook_plugged_cb = drm_connector_hdmi_audio_hook_plugged_cb,
+};
+
+/**
+ * drm_connector_hdmi_audio_init - Initialize HDMI Codec device for the DRM connector
+ * @connector: A pointer to the connector to allocate codec for
+ * @hdmi_codec_dev: device to be used as a parent for the HDMI Codec
+ * @funcs: callbacks for this HDMI Codec
+ * @max_i2s_playback_channels: maximum number of playback I2S channels
+ * @spdif_playback: set if HDMI codec has S/PDIF playback port
+ * @dai_port: sound DAI port, -1 if it is not enabled
+ *
+ * Create a HDMI codec device to be used with the specified connector.
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drm_connector_hdmi_audio_init(struct drm_connector *connector,
+				  struct device *hdmi_codec_dev,
+				  const struct drm_connector_hdmi_audio_funcs *funcs,
+				  unsigned int max_i2s_playback_channels,
+				  bool spdif_playback,
+				  int dai_port)
+{
+	struct hdmi_codec_pdata codec_pdata = {
+		.ops = &drm_connector_hdmi_audio_ops,
+		.max_i2s_channels = max_i2s_playback_channels,
+		.i2s = !!max_i2s_playback_channels,
+		.spdif = spdif_playback,
+		.no_i2s_capture = true,
+		.no_spdif_capture = true,
+		.data = connector,
+	};
+	struct platform_device *pdev;
+
+	if (!funcs ||
+	    !funcs->prepare ||
+	    !funcs->shutdown)
+		return -EINVAL;
+
+	connector->hdmi_audio.funcs = funcs;
+	connector->hdmi_audio.dai_port = dai_port;
+
+	pdev = platform_device_register_data(hdmi_codec_dev,
+					     HDMI_CODEC_DRV_NAME,
+					     PLATFORM_DEVID_AUTO,
+					     &codec_pdata, sizeof(codec_pdata));
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	connector->hdmi_audio.codec_pdev = pdev;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_connector_hdmi_audio_init);
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index ae6e71305f3000aff1cfe96b050061a300b9478e..1383fa9fff9bcf31488453e209a36c6fe97be2f1 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -33,6 +33,7 @@
 #include <drm/drm_sysfs.h>
 #include <drm/drm_utils.h>
 
+#include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/uaccess.h>
 
@@ -281,6 +282,7 @@ static int drm_connector_init_only(struct drm_device *dev,
 	mutex_init(&connector->eld_mutex);
 	mutex_init(&connector->edid_override_mutex);
 	mutex_init(&connector->hdmi.infoframes.lock);
+	mutex_init(&connector->hdmi_audio.lock);
 	connector->edid_blob_ptr = NULL;
 	connector->epoch_counter = 0;
 	connector->tile_blob_ptr = NULL;
@@ -714,6 +716,8 @@ void drm_connector_cleanup(struct drm_connector *connector)
 		    DRM_CONNECTOR_REGISTERED))
 		drm_connector_unregister(connector);
 
+	platform_device_unregister(connector->hdmi_audio.codec_pdev);
+
 	if (connector->privacy_screen) {
 		drm_privacy_screen_put(connector->privacy_screen);
 		connector->privacy_screen = NULL;
@@ -750,6 +754,7 @@ void drm_connector_cleanup(struct drm_connector *connector)
 		connector->funcs->atomic_destroy_state(connector,
 						       connector->state);
 
+	mutex_destroy(&connector->hdmi_audio.lock);
 	mutex_destroy(&connector->hdmi.infoframes.lock);
 	mutex_destroy(&connector->mutex);
 
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index d1be19242a5c5d7ab6b38cced1da336830b3848d..19e4256296657b0f1d203266d152cbba42f9726a 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -46,6 +46,8 @@ struct drm_property_blob;
 struct drm_printer;
 struct drm_privacy_screen;
 struct edid;
+struct hdmi_codec_daifmt;
+struct hdmi_codec_params;
 struct i2c_adapter;
 
 enum drm_connector_force {
@@ -1141,6 +1143,53 @@ struct drm_connector_state {
 	struct drm_connector_hdmi_state hdmi;
 };
 
+struct drm_connector_hdmi_audio_funcs {
+	/**
+	 * @startup:
+	 *
+	 * Called when ASoC starts an audio stream setup. The
+	 * @startup() is optional.
+	 *
+	 * Returns:
+	 * 0 on success, a negative error code otherwise
+	 */
+	int (*startup)(struct drm_connector *connector);
+
+	/**
+	 * @prepare:
+	 * Configures HDMI-encoder for audio stream. Can be called
+	 * multiple times for each setup. Mandatory.
+	 *
+	 * Returns:
+	 * 0 on success, a negative error code otherwise
+	 */
+	int (*prepare)(struct drm_connector *connector,
+		       struct hdmi_codec_daifmt *fmt,
+		       struct hdmi_codec_params *hparms);
+
+	/**
+	 * @shutdown:
+	 *
+	 * Shut down the audio stream. Mandatory.
+	 *
+	 * Returns:
+	 * 0 on success, a negative error code otherwise
+	 */
+	void (*shutdown)(struct drm_connector *connector);
+
+	/**
+	 * @mute_stream:
+	 *
+	 * Mute/unmute HDMI audio stream. The @mute_stream callback is
+	 * optional.
+	 *
+	 * Returns:
+	 * 0 on success, a negative error code otherwise
+	 */
+	int (*mute_stream)(struct drm_connector *connector,
+			   bool enable, int direction);
+};
+
 /**
  * struct drm_connector_hdmi_funcs - drm_hdmi_connector control functions
  */
@@ -1660,6 +1709,68 @@ struct drm_cmdline_mode {
 	bool tv_mode_specified;
 };
 
+/**
+ * struct drm_connector_hdmi_audio - DRM gemeric HDMI Codec-related structure
+ *
+ * HDMI drivers usually incorporate a HDMI Codec. This structure expresses the
+ * generic HDMI Codec as used by the DRM HDMI Codec framework.
+ */
+struct drm_connector_hdmi_audio {
+	/**
+	 * @funcs:
+	 *
+	 * Implementation of the HDMI codec functionality to be used by the DRM
+	 * HDMI Codec framework.
+	 */
+	const struct drm_connector_hdmi_audio_funcs *funcs;
+
+	/**
+	 * @codec_pdev:
+	 *
+	 * Platform device created to hold the HDMI Codec. It will be
+	 * automatically unregistered during drm_connector_cleanup().
+	 */
+	struct platform_device *codec_pdev;
+
+	/**
+	 * @lock:
+	 *
+	 * Mutex to protect @last_state, @plugged_cb and @plugged_cb_dev.
+	 */
+	struct mutex lock;
+
+	/**
+	 * @plugged_cb:
+	 *
+	 * Callback to be called when the HDMI sink get plugged to or unplugged
+	 * from this connector. This is assigned by the framework when
+	 * requested by the ASoC code.
+	 */
+	void (*plugged_cb)(struct device *dev, bool plugged);
+
+	/**
+	 * @plugged_cb_dev:
+	 *
+	 * The data for @plugged_cb(). It is being provided by the ASoC.
+	 */
+	struct device *plugged_cb_dev;
+
+	/**
+	 * @last_state:
+	 *
+	 * Last plugged state recored by the framework. It is used to correctly
+	 * report the state to @plugged_cb().
+	 */
+	bool last_state;
+
+	/**
+	 * @dai_port:
+	 *
+	 * The port in DT that is used for the Codec DAI.
+	 */
+	int dai_port;
+};
+
 /*
  * struct drm_connector_hdmi - DRM Connector HDMI-related structure
  */
@@ -2121,6 +2232,11 @@ struct drm_connector {
 	 * @hdmi: HDMI-related variable and properties.
 	 */
 	struct drm_connector_hdmi hdmi;
+
+	/**
+	 * @hdmi_audio: HDMI codec properties and non-DRM state.
+	 */
+	struct drm_connector_hdmi_audio hdmi_audio;
 };
 
 #define obj_to_connector(x) container_of(x, struct drm_connector, base)
@@ -2153,6 +2269,12 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
 			     struct i2c_adapter *ddc,
 			     unsigned long supported_formats,
 			     unsigned int max_bpc);
+int drm_connector_hdmi_audio_init(struct drm_connector *connector,
+				  struct device *hdmi_codec_dev,
+				  const struct drm_connector_hdmi_audio_funcs *funcs,
+				  unsigned int max_i2s_playback_channels,
+				  bool spdif_playback,
+				  int sound_dai_port);
 void drm_connector_attach_edid_property(struct drm_connector *connector);
 int drm_connector_register(struct drm_connector *connector);
 int drm_connector_dynamic_register(struct drm_connector *connector);
@@ -2160,6 +2282,9 @@ void drm_connector_unregister(struct drm_connector *connector);
 int drm_connector_attach_encoder(struct drm_connector *connector,
 				      struct drm_encoder *encoder);
 
+void drm_connector_hdmi_audio_plugged_notify(struct drm_connector *connector,
+					     bool plugged);
+
 void drm_connector_cleanup(struct drm_connector *connector);
 
 static inline unsigned int drm_connector_index(const struct drm_connector *connector)

-- 
2.39.5

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