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@kernel.org>
Tested-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241224-drm-bridge-hdmi-connector-v10-3-dc89577cd438@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

2 files changed, 138 insertions, 0 deletions

diff --git a/include/drm/display/drm_hdmi_audio_helper.h b/include/drm/display/drm_hdmi_audio_helper.h
new file mode 100644
index 000000000000..c9a6faef4109
--- /dev/null
+++ b/include/drm/display/drm_hdmi_audio_helper.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: MIT */
+
+#ifndef DRM_DISPLAY_HDMI_AUDIO_HELPER_H_
+#define DRM_DISPLAY_HDMI_AUDIO_HELPER_H_
+
+#include <linux/types.h>
+
+struct drm_connector;
+struct drm_connector_hdmi_audio_funcs;
+
+struct device;
+
+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_hdmi_audio_plugged_notify(struct drm_connector *connector,
+					     bool plugged);
+
+#endif
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index d1be19242a5c..1d4c27948e87 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)