Message-Id: <20240615-drm-bridge-hdmi-connector-v1-3-d59fc7865ab2@linaro.org>
Date: Sat, 15 Jun 2024 20:53:32 +0300
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>, Daniel Vetter <daniel@...ll.ch>, 
 Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>, 
 Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 linux-sound@...r.kernel.org
Subject: [PATCH RFC 3/5] drm/connector: implement generic HDMI codec
 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.

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

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
---
 drivers/gpu/drm/Makefile                   |   1 +
 drivers/gpu/drm/drm_connector.c            |   8 ++
 drivers/gpu/drm/drm_connector_hdmi_codec.c | 157 +++++++++++++++++++++++++++++
 include/drm/drm_connector.h                |  33 ++++++
 4 files changed, 199 insertions(+)

diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 68cc9258ffc4..e113a6eade23 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -45,6 +45,7 @@ drm-y := \
 	drm_client_modeset.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 3d73a981004c..66d6e9487339 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -279,6 +279,7 @@ static int __drm_connector_init(struct drm_device *dev,
 	mutex_init(&connector->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;
@@ -529,6 +530,12 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
 
 	connector->hdmi.funcs = hdmi_funcs;
 
+	if (connector->hdmi_codec.i2s || connector->hdmi_codec.spdif) {
+		ret = drmm_connector_hdmi_codec_alloc(dev, connector, hdmi_funcs->codec_ops);
+		if (ret)
+			return ret;
+	}
+
 	return 0;
 }
 EXPORT_SYMBOL(drmm_connector_hdmi_init);
@@ -665,6 +672,7 @@ 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 000000000000..a3a7ad117f6f
--- /dev/null
+++ b/drivers/gpu/drm/drm_connector_hdmi_codec.c
@@ -0,0 +1,157 @@
+/*
+ * Copyright (c) 2024 Linaro Ltd
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#include <linux/mutex.h>
+#include <linux/platform_device.h>
+
+#include <drm/drm_connector.h>
+#include <drm/drm_managed.h>
+
+#include <sound/hdmi-codec.h>
+
+static int drm_connector_hdmi_codec_get_eld(struct device *dev, void *data,
+					    uint8_t *buf, size_t len)
+{
+	struct drm_connector *connector = data;
+
+	//  FIXME: locking against drm_edid_to_eld ?
+	memcpy(buf, connector->eld, min(sizeof(connector->eld), len));
+
+	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 void drm_connector_hdmi_codec_cleanup_action(struct drm_device *dev,
+						    void *ptr)
+{
+	struct platform_device *pdev = ptr;
+
+	platform_device_unregister(pdev);
+}
+
+/**
+ * drmm_connector_hdmi_alloc - Allocate HDMI Codec device for the DRM connector
+ * @dev: DRM device
+ * @connector: A pointer to the connector to allocate codec for
+ * @ops: callbacks for this connector
+ *
+ * Create a HDMI codec device to be used with the specified connector.
+ *
+ * Cleanup is automatically handled with in a DRM-managed action.
+ *
+ * The connector structure should be allocated with drmm_kzalloc().
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drmm_connector_hdmi_codec_alloc(struct drm_device *dev,
+				    struct drm_connector *connector,
+				    const struct hdmi_codec_ops *base_ops)
+{
+	struct hdmi_codec_pdata codec_pdata = {};
+	struct platform_device *pdev;
+	struct hdmi_codec_ops *ops;
+	int ret;
+
+	ops = drmm_kmalloc(dev, sizeof(*ops), GFP_KERNEL);
+	if (!ops)
+		return -ENOMEM;
+
+	*ops = *base_ops;
+
+	ops->get_eld = drm_connector_hdmi_codec_get_eld;
+	ops->hook_plugged_cb = drm_connector_hdmi_codec_hook_plugged_cb;
+
+	codec_pdata.ops = ops;
+	codec_pdata.i2s = connector->hdmi_codec.i2s,
+	codec_pdata.spdif = connector->hdmi_codec.spdif,
+	codec_pdata.max_i2s_channels = connector->hdmi_codec.max_i2s_channels,
+	codec_pdata.data = connector;
+
+	pdev = platform_device_register_data(connector->hdmi_codec.parent_dev,
+					     HDMI_CODEC_DRV_NAME,
+					     PLATFORM_DEVID_AUTO,
+					     &codec_pdata, sizeof(codec_pdata));
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	ret = drmm_add_action_or_reset(dev, drm_connector_hdmi_codec_cleanup_action, pdev);
+	if (ret)
+		return ret;
+
+	connector->hdmi_codec.codec_pdev = pdev;
+
+	return 0;
+}
+EXPORT_SYMBOL(drmm_connector_hdmi_codec_alloc);
+
+/**
+ * drmm_connector_hdmi_codec_free - rollback drmm_connector_hdmi_codec_alloc
+ * @dev: DRM device
+ * @hdmi_codec: A pointer to the HDMI codec data
+ *
+ * Rollback the drmm_connector_hdmi_codec_alloc() and free allocated data.
+ * While this function should not be necessary for a typical driver, DRM bridge
+ * drivers have to call it from the remove callback if the bridge uses
+ * Connector's HDMI Codec interface.
+ */
+void drmm_connector_hdmi_codec_free(struct drm_device *dev,
+				    struct drm_connector_hdmi_codec *hdmi_codec)
+{
+	drmm_release_action(dev, drm_connector_hdmi_codec_cleanup_action,
+			    hdmi_codec->codec_pdev);
+}
+EXPORT_SYMBOL(drmm_connector_hdmi_codec_free);
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index f750765d8fbc..0eb8d8ed9495 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -46,6 +46,7 @@ struct drm_property_blob;
 struct drm_printer;
 struct drm_privacy_screen;
 struct edid;
+struct hdmi_codec_ops;
 struct i2c_adapter;
 
 enum drm_connector_force {
@@ -1199,6 +1200,8 @@ struct drm_connector_hdmi_funcs {
 	int (*write_infoframe)(struct drm_connector *connector,
 			       enum hdmi_infoframe_type type,
 			       const u8 *buffer, size_t len);
+
+	const struct hdmi_codec_ops *codec_ops;
 };
 
 /**
@@ -1706,6 +1709,22 @@ struct drm_connector_hdmi {
 	} infoframes;
 };
 
+struct drm_connector_hdmi_codec {
+	struct device *parent_dev;
+	struct platform_device *codec_pdev;
+
+	const struct drm_connector_hdmi_codec_funcs *funcs;
+
+	struct mutex lock; /* protects last_state and plugged_cb */
+	void (*plugged_cb)(struct device *dev, bool plugged);
+	struct device *plugged_cb_dev;
+	bool last_state;
+
+	int max_i2s_channels;
+	uint i2s: 1;
+	uint spdif: 1;
+};
+
 /**
  * struct drm_connector - central DRM connector control structure
  *
@@ -2119,6 +2138,12 @@ struct drm_connector {
 	 * @hdmi: HDMI-related variable and properties.
 	 */
 	struct drm_connector_hdmi hdmi;
+
+	/**
+	 * @hdmi_codec: HDMI codec properties and variables. Also might be used
+	 * for DisplayPort audio.
+	 */
+	struct drm_connector_hdmi_codec hdmi_codec;
 };
 
 #define obj_to_connector(x) container_of(x, struct drm_connector, base)
@@ -2152,6 +2177,14 @@ void drm_connector_unregister(struct drm_connector *connector);
 int drm_connector_attach_encoder(struct drm_connector *connector,
 				      struct drm_encoder *encoder);
 
+int drmm_connector_hdmi_codec_alloc(struct drm_device *dev,
+				    struct drm_connector *connector,
+				    const struct hdmi_codec_ops *ops);
+void drmm_connector_hdmi_codec_free(struct drm_device *dev,
+				    struct drm_connector_hdmi_codec *codec);
+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)

-- 
2.39.2

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