[PATCH v7 03/10] drm/connector: implement generic HDMI codec helpers

Dmitry Baryshkov
2024-12-17T00:45:04Z

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.

The framework is integrated with the DRM HDMI Connector framework, but
can be used by DisplayPort drivers.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
drivers/gpu/drm/Makefile | 1 +
drivers/gpu/drm/drm_connector.c | 5 +
drivers/gpu/drm/drm_connector_hdmi_codec.c | 189 +++++++++++++++++++++++++++++
include/drm/drm_connector.h | 125 +++++++++++++++++++
4 files changed, 320 insertions(+)

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 19fb370fbc56772077973c864df71e4b8e0bf99b..46e6dbc355afe4015ff2327ba04211cdc011a0b7 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -42,6 +42,7 @@ drm-y := \
drm_cache.o \
drm_color_mgmt.o \
drm_connector.o \
+ drm_connector_hdmi_codec.o \
drm_crtc.o \
drm_displayid.o \
drm_drv.o \
diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index bbdaaf7022b62d84594a29f1b60144920903a99a..4abfbded962bf45b793a2bd5b1b5c4d9f478a1f7 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>

@@ -280,6 +281,7 @@ static int __drm_connector_init(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_codec.lock);
connector->edid_blob_ptr = NULL;
connector->epoch_counter = 0;
connector->tile_blob_ptr = NULL;
@@ -632,6 +634,8 @@ void drm_connector_cleanup(struct drm_connector *connector)
DRM_CONNECTOR_REGISTERED))
drm_connector_unregister(connector);

+ platform_device_unregister(connector->hdmi_codec.codec_pdev);
+
if (connector->privacy_screen) {
drm_privacy_screen_put(connector->privacy_screen);
connector->privacy_screen = NULL;
@@ -670,6 +674,7 @@ void drm_connector_cleanup(struct drm_connector *connector)
connector->funcs->atomic_destroy_state(connector,
connector->state);

+ mutex_destroy(&connector->hdmi_codec.lock);
mutex_destroy(&connector->hdmi.infoframes.lock);
mutex_destroy(&connector->mutex);

diff --git a/drivers/gpu/drm/drm_connector_hdmi_codec.c b/drivers/gpu/drm/drm_connector_hdmi_codec.c
new file mode 100644
index 0000000000000000000000000000000000000000..a6e2f27c3f7ff9d57cf19c055870001daff4c676
--- /dev/null
+++ b/drivers/gpu/drm/drm_connector_hdmi_codec.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_codec_audio_startup(struct device *dev, void *data)
+{
+ struct drm_connector *connector = data;
+ const struct drm_connector_hdmi_codec_funcs *funcs =
+ connector->hdmi_codec.funcs;
+
+ if (funcs->audio_startup)
+ return funcs->audio_startup(connector);
+
+ return 0;
+}
+
+static int drm_connector_hdmi_codec_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_codec_funcs *funcs =
+ connector->hdmi_codec.funcs;
+
+ return funcs->prepare(connector, fmt, hparms);
+}
+
+static void drm_connector_hdmi_codec_audio_shutdown(struct device *dev, void *data)
+{
+ struct drm_connector *connector = data;
+ const struct drm_connector_hdmi_codec_funcs *funcs =
+ connector->hdmi_codec.funcs;
+
+ return funcs->audio_shutdown(connector);
+}
+
+static int drm_connector_hdmi_codec_mute_stream(struct device *dev, void *data,
+ bool enable, int direction)
+{
+ struct drm_connector *connector = data;
+ const struct drm_connector_hdmi_codec_funcs *funcs =
+ connector->hdmi_codec.funcs;
+
+ if (funcs->mute_stream)
+ return funcs->mute_stream(connector, enable, direction);
+
+ return -ENOTSUPP;
+}
+
+static int drm_connector_hdmi_codec_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_codec.dai_port < 0)
+ return -ENOTSUPP;
+
+ ret = of_graph_parse_endpoint(endpoint, &of_ep);
+ if (ret < 0)
+ return ret;
+
+ if (of_ep.port == connector->hdmi_codec.dai_port)
+ return 0;
+
+ return -EINVAL;
+}
+
+static int drm_connector_hdmi_codec_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_codec_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_codec.lock);
+
+ connector->hdmi_codec.plugged_cb = fn;
+ connector->hdmi_codec.plugged_cb_dev = codec_dev;
+
+ fn(codec_dev, connector->hdmi_codec.last_state);
+
+ mutex_unlock(&connector->hdmi_codec.lock);
+
+ return 0;
+}
+
+void drm_connector_hdmi_codec_plugged_notify(struct drm_connector *connector,
+ bool plugged)
+{
+ mutex_lock(&connector->hdmi_codec.lock);
+
+ connector->hdmi_codec.last_state = plugged;
+
+ if (connector->hdmi_codec.plugged_cb &&
+ connector->hdmi_codec.plugged_cb_dev)
+ connector->hdmi_codec.plugged_cb(connector->hdmi_codec.plugged_cb_dev,
+ connector->hdmi_codec.last_state);
+
+ mutex_unlock(&connector->hdmi_codec.lock);
+}
+EXPORT_SYMBOL(drm_connector_hdmi_codec_plugged_notify);
+
+static const struct hdmi_codec_ops drm_connector_hdmi_codec_ops = {
+ .audio_startup = drm_connector_hdmi_codec_audio_startup,
+ .prepare = drm_connector_hdmi_codec_prepare,
+ .audio_shutdown = drm_connector_hdmi_codec_audio_shutdown,
+ .mute_stream = drm_connector_hdmi_codec_mute_stream,
+ .get_eld = drm_connector_hdmi_codec_get_eld,
+ .get_dai_id = drm_connector_hdmi_codec_get_dai_id,
+ .hook_plugged_cb = drm_connector_hdmi_codec_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_codec_funcs *funcs,
+ unsigned int max_i2s_playback_channels,
+ bool spdif_playback,
+ int dai_port)
+{
+ struct hdmi_codec_pdata codec_pdata = {
+ .ops = &drm_connector_hdmi_codec_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->audio_shutdown)
+ return -EINVAL;
+
+ connector->hdmi_codec.funcs = funcs;
+ connector->hdmi_codec.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_codec.codec_pdev = pdev;
+
+ return 0;
+}
+EXPORT_SYMBOL(drm_connector_hdmi_audio_init);
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 1e2b25e204cb523d61d30f5409faa059bf2b86eb..536d604b6fb27368c43805a2ecf57fac06b3d472 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_codec_funcs {
+ /**
+ * @audio_startup:
+ *
+ * Called when ASoC starts an audio stream setup. The
+ * @hdmi_audio_startup is optional.
+ *
+ * Returns:
+ * 0 on success, a negative error code otherwise
+ */
+ int (*audio_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);
+
+ /**
+ * @audio_shutdown:
+ *
+ * Shut down the audio stream. Mandatory.
+ *
+ * Returns:
+ * 0 on success, a negative error code otherwise
+ */
+ void (*audio_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_codec - 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_codec {
+ /**
+ * @funcs:
+ *
+ * Implementation of the HDMI codec functionality to be used by the DRM
+ * HDMI Codec framework.
+ */
+ const struct drm_connector_hdmi_codec_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_codec: HDMI codec properties and non-DRM state.
+ */
+ struct drm_connector_hdmi_codec hdmi_codec;
};

#define obj_to_connector(x) container_of(x, struct drm_connector, base)
@@ -2148,12 +2264,21 @@ 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_codec_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);
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_codec_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