media: cec: extron-da-hd-4k-plus: add the Extron DA HD 4K Plus CEC driver

Add support for the Extron DA HD 4K Plus series of 4K HDMI
Distrubution Amplifiers (aka HDMI Splitters).

These devices support CEC and this driver adds support for the
CEC protocol for both the input and all outputs (2, 4 or 6 outputs,
depending on the model).

It also exports the EDID from the outputs and allows reading and
setting the EDID of the input.

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

8 files changed, 2686 insertions, 0 deletions

diff --git a/drivers/media/cec/usb/Kconfig b/drivers/media/cec/usb/Kconfig
index 3f3a5c75287a..6faf4742981d 100644
--- a/drivers/media/cec/usb/Kconfig
+++ b/drivers/media/cec/usb/Kconfig
@@ -3,6 +3,7 @@
 # USB drivers
 
 if USB_SUPPORT && TTY
+source "drivers/media/cec/usb/extron-da-hd-4k-plus/Kconfig"
 source "drivers/media/cec/usb/pulse8/Kconfig"
 source "drivers/media/cec/usb/rainshadow/Kconfig"
 endif
diff --git a/drivers/media/cec/usb/Makefile b/drivers/media/cec/usb/Makefile
index e4183d1bfa9a..c082679f5318 100644
--- a/drivers/media/cec/usb/Makefile
+++ b/drivers/media/cec/usb/Makefile
@@ -2,5 +2,6 @@
 #
 # Makefile for the CEC USB device drivers.
 #
+obj-$(CONFIG_USB_EXTRON_DA_HD_4K_PLUS_CEC) += extron-da-hd-4k-plus/
 obj-$(CONFIG_USB_PULSE8_CEC) += pulse8/
 obj-$(CONFIG_USB_RAINSHADOW_CEC) += rainshadow/
diff --git a/drivers/media/cec/usb/extron-da-hd-4k-plus/Kconfig b/drivers/media/cec/usb/extron-da-hd-4k-plus/Kconfig
new file mode 100644
index 000000000000..5354f0eebe5c
--- /dev/null
+++ b/drivers/media/cec/usb/extron-da-hd-4k-plus/Kconfig
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config USB_EXTRON_DA_HD_4K_PLUS_CEC
+	tristate "Extron DA HD 4K Plus CEC driver"
+	depends on VIDEO_DEV
+	depends on USB
+	depends on USB_ACM
+	select CEC_CORE
+	select SERIO
+	select SERIO_SERPORT
+	help
+	  This is a CEC driver for the Extron DA HD 4K Plus HDMI Splitter.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called extron-da-hd-4k-plus-cec.
diff --git a/drivers/media/cec/usb/extron-da-hd-4k-plus/Makefile b/drivers/media/cec/usb/extron-da-hd-4k-plus/Makefile
new file mode 100644
index 000000000000..2e8f7f60263f
--- /dev/null
+++ b/drivers/media/cec/usb/extron-da-hd-4k-plus/Makefile
@@ -0,0 +1,8 @@
+extron-da-hd-4k-plus-cec-objs := extron-da-hd-4k-plus.o cec-splitter.o
+obj-$(CONFIG_USB_EXTRON_DA_HD_4K_PLUS_CEC) := extron-da-hd-4k-plus-cec.o
+
+all:
+	$(MAKE) -C $(KDIR) M=$(shell pwd) modules
+
+install:
+	$(MAKE) -C $(KDIR) M=$(shell pwd) modules_install
diff --git a/drivers/media/cec/usb/extron-da-hd-4k-plus/cec-splitter.c b/drivers/media/cec/usb/extron-da-hd-4k-plus/cec-splitter.c
new file mode 100644
index 000000000000..73fdec4b791d
--- /dev/null
+++ b/drivers/media/cec/usb/extron-da-hd-4k-plus/cec-splitter.c
@@ -0,0 +1,657 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+/*
+ * Copyright 2021-2024 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ */
+
+#include <media/cec.h>
+
+#include "cec-splitter.h"
+
+/*
+ * Helper function to reply to a received message with a Feature Abort
+ * message.
+ */
+static int cec_feature_abort_reason(struct cec_adapter *adap,
+				    struct cec_msg *msg, u8 reason)
+{
+	struct cec_msg tx_msg = { };
+
+	/*
+	 * Don't reply with CEC_MSG_FEATURE_ABORT to a CEC_MSG_FEATURE_ABORT
+	 * message!
+	 */
+	if (msg->msg[1] == CEC_MSG_FEATURE_ABORT)
+		return 0;
+	/* Don't Feature Abort messages from 'Unregistered' */
+	if (cec_msg_initiator(msg) == CEC_LOG_ADDR_UNREGISTERED)
+		return 0;
+	cec_msg_set_reply_to(&tx_msg, msg);
+	cec_msg_feature_abort(&tx_msg, msg->msg[1], reason);
+	return cec_transmit_msg(adap, &tx_msg, false);
+}
+
+/* Transmit an Active Source message from this output port to a sink */
+static void cec_port_out_active_source(struct cec_splitter_port *p)
+{
+	struct cec_adapter *adap = p->adap;
+	struct cec_msg msg;
+
+	if (!adap->is_configured)
+		return;
+	p->is_active_source = true;
+	cec_msg_init(&msg, adap->log_addrs.log_addr[0], 0);
+	cec_msg_active_source(&msg, adap->phys_addr);
+	cec_transmit_msg(adap, &msg, false);
+}
+
+/* Transmit Active Source messages from all output ports to the sinks */
+static void cec_out_active_source(struct cec_splitter *splitter)
+{
+	unsigned int i;
+
+	for (i = 0; i < splitter->num_out_ports; i++)
+		cec_port_out_active_source(splitter->ports[i]);
+}
+
+/* Transmit a Standby message from this output port to a sink */
+static void cec_port_out_standby(struct cec_splitter_port *p)
+{
+	struct cec_adapter *adap = p->adap;
+	struct cec_msg msg;
+
+	if (!adap->is_configured)
+		return;
+	cec_msg_init(&msg, adap->log_addrs.log_addr[0], 0);
+	cec_msg_standby(&msg);
+	cec_transmit_msg(adap, &msg, false);
+}
+
+/* Transmit Standby messages from all output ports to the sinks */
+static void cec_out_standby(struct cec_splitter *splitter)
+{
+	unsigned int i;
+
+	for (i = 0; i < splitter->num_out_ports; i++)
+		cec_port_out_standby(splitter->ports[i]);
+}
+
+/* Transmit an Image/Text View On message from this output port to a sink */
+static void cec_port_out_wakeup(struct cec_splitter_port *p, u8 opcode)
+{
+	struct cec_adapter *adap = p->adap;
+	u8 la = adap->log_addrs.log_addr[0];
+	struct cec_msg msg;
+
+	if (la == CEC_LOG_ADDR_INVALID)
+		la = CEC_LOG_ADDR_UNREGISTERED;
+	cec_msg_init(&msg, la, 0);
+	msg.len = 2;
+	msg.msg[1] = opcode;
+	cec_transmit_msg(adap, &msg, false);
+}
+
+/* Transmit Image/Text View On messages from all output ports to the sinks */
+static void cec_out_wakeup(struct cec_splitter *splitter, u8 opcode)
+{
+	unsigned int i;
+
+	for (i = 0; i < splitter->num_out_ports; i++)
+		cec_port_out_wakeup(splitter->ports[i], opcode);
+}
+
+/*
+ * Update the power state of the unconfigured CEC device to either
+ * Off or On depending on the current state of the splitter.
+ * This keeps the outputs in a consistent state.
+ */
+void cec_splitter_unconfigured_output(struct cec_splitter_port *p)
+{
+	p->video_latency = 1;
+	p->power_status = p->splitter->is_standby ?
+		CEC_OP_POWER_STATUS_TO_STANDBY : CEC_OP_POWER_STATUS_TO_ON;
+
+	/* The adapter was unconfigured, so clear the sequence and ts values */
+	p->out_give_device_power_status_seq = 0;
+	p->out_give_device_power_status_ts = ktime_set(0, 0);
+	p->out_request_current_latency_seq = 0;
+	p->out_request_current_latency_ts = ktime_set(0, 0);
+}
+
+/*
+ * Update the power state of the newly configured CEC device to either
+ * Off or On depending on the current state of the splitter.
+ * This keeps the outputs in a consistent state.
+ */
+void cec_splitter_configured_output(struct cec_splitter_port *p)
+{
+	p->video_latency = 1;
+	p->power_status = p->splitter->is_standby ?
+		CEC_OP_POWER_STATUS_TO_STANDBY : CEC_OP_POWER_STATUS_TO_ON;
+
+	if (p->splitter->is_standby) {
+		/*
+		 * Some sinks only obey Standby if it comes from the
+		 * active source.
+		 */
+		cec_port_out_active_source(p);
+		cec_port_out_standby(p);
+	} else {
+		cec_port_out_wakeup(p, CEC_MSG_IMAGE_VIEW_ON);
+	}
+}
+
+/* Pass the in_msg on to all output ports */
+static void cec_out_passthrough(struct cec_splitter *splitter,
+				const struct cec_msg *in_msg)
+{
+	unsigned int i;
+
+	for (i = 0; i < splitter->num_out_ports; i++) {
+		struct cec_splitter_port *p = splitter->ports[i];
+		struct cec_adapter *adap = p->adap;
+		struct cec_msg msg;
+
+		if (!adap->is_configured)
+			continue;
+		cec_msg_init(&msg, adap->log_addrs.log_addr[0], 0);
+		msg.len = in_msg->len;
+		memcpy(msg.msg + 1, in_msg->msg + 1, msg.len - 1);
+		cec_transmit_msg(adap, &msg, false);
+	}
+}
+
+/*
+ * See if all output ports received the Report Current Latency message,
+ * and if so, transmit the result from the input port to the video source.
+ */
+static void cec_out_report_current_latency(struct cec_splitter *splitter,
+					   struct cec_adapter *input_adap)
+{
+	struct cec_msg reply = {};
+	unsigned int reply_lat = 0;
+	unsigned int cnt = 0;
+	unsigned int i;
+
+	for (i = 0; i < splitter->num_out_ports; i++) {
+		struct cec_splitter_port *p = splitter->ports[i];
+		struct cec_adapter *adap = p->adap;
+
+		/* Skip unconfigured ports */
+		if (!adap->is_configured)
+			continue;
+		/* Return if a port is still waiting for a reply */
+		if (p->out_request_current_latency_seq)
+			return;
+		reply_lat += p->video_latency - 1;
+		cnt++;
+	}
+
+	/*
+	 * All ports that can reply, replied, so clear the sequence
+	 * and timestamp values.
+	 */
+	for (i = 0; i < splitter->num_out_ports; i++) {
+		struct cec_splitter_port *p = splitter->ports[i];
+
+		p->out_request_current_latency_seq = 0;
+		p->out_request_current_latency_ts = ktime_set(0, 0);
+	}
+
+	/*
+	 * Return if there were no replies or the input port is no longer
+	 * configured.
+	 */
+	if (!cnt || !input_adap->is_configured)
+		return;
+
+	/* Reply with the average latency */
+	reply_lat = 1 + reply_lat / cnt;
+	cec_msg_init(&reply, input_adap->log_addrs.log_addr[0],
+		     splitter->request_current_latency_dest);
+	cec_msg_report_current_latency(&reply, input_adap->phys_addr,
+				       reply_lat, 1, 1, 1);
+	cec_transmit_msg(input_adap, &reply, false);
+}
+
+/* Transmit Request Current Latency to all output ports */
+static int cec_out_request_current_latency(struct cec_splitter *splitter)
+{
+	ktime_t now = ktime_get();
+	bool error = true;
+	unsigned int i;
+
+	for (i = 0; i < splitter->num_out_ports; i++) {
+		struct cec_splitter_port *p = splitter->ports[i];
+		struct cec_adapter *adap = p->adap;
+
+		if (!adap->is_configured) {
+			/* Clear if not configured */
+			p->out_request_current_latency_seq = 0;
+			p->out_request_current_latency_ts = ktime_set(0, 0);
+		} else if (!p->out_request_current_latency_seq) {
+			/*
+			 * Keep the old ts if an earlier request is still
+			 * pending. This ensures that the request will
+			 * eventually time out based on the timestamp of
+			 * the first request if the sink is unresponsive.
+			 */
+			p->out_request_current_latency_ts = now;
+		}
+	}
+
+	for (i = 0; i < splitter->num_out_ports; i++) {
+		struct cec_splitter_port *p = splitter->ports[i];
+		struct cec_adapter *adap = p->adap;
+		struct cec_msg msg;
+
+		if (!adap->is_configured)
+			continue;
+		cec_msg_init(&msg, adap->log_addrs.log_addr[0], 0);
+		cec_msg_request_current_latency(&msg, true, adap->phys_addr);
+		if (cec_transmit_msg(adap, &msg, false))
+			continue;
+		p->out_request_current_latency_seq = msg.sequence | (1U << 31);
+		error = false;
+	}
+	return error ? -ENODEV : 0;
+}
+
+/*
+ * See if all output ports received the Report Power Status message,
+ * and if so, transmit the result from the input port to the video source.
+ */
+static void cec_out_report_power_status(struct cec_splitter *splitter,
+					struct cec_adapter *input_adap)
+{
+	struct cec_msg reply = {};
+	/* The target power status of the splitter itself */
+	u8 splitter_pwr = splitter->is_standby ?
+		CEC_OP_POWER_STATUS_STANDBY : CEC_OP_POWER_STATUS_ON;
+	/*
+	 * The transient power status of the splitter, used if not all
+	 * output report the target power status.
+	 */
+	u8 splitter_transient_pwr = splitter->is_standby ?
+		CEC_OP_POWER_STATUS_TO_STANDBY : CEC_OP_POWER_STATUS_TO_ON;
+	u8 reply_pwr = splitter_pwr;
+	unsigned int i;
+
+	for (i = 0; i < splitter->num_out_ports; i++) {
+		struct cec_splitter_port *p = splitter->ports[i];
+
+		/* Skip if no sink was found (HPD was low for more than 5s) */
+		if (!p->found_sink)
+			continue;
+
+		/* Return if a port is still waiting for a reply */
+		if (p->out_give_device_power_status_seq)
+			return;
+		if (p->power_status != splitter_pwr)
+			reply_pwr = splitter_transient_pwr;
+	}
+
+	/*
+	 * All ports that can reply, replied, so clear the sequence
+	 * and timestamp values.
+	 */
+	for (i = 0; i < splitter->num_out_ports; i++) {
+		struct cec_splitter_port *p = splitter->ports[i];
+
+		p->out_give_device_power_status_seq = 0;
+		p->out_give_device_power_status_ts = ktime_set(0, 0);
+	}
+
+	/* Return if the input port is no longer configured. */
+	if (!input_adap->is_configured)
+		return;
+
+	/* Reply with the new power status */
+	cec_msg_init(&reply, input_adap->log_addrs.log_addr[0],
+		     splitter->give_device_power_status_dest);
+	cec_msg_report_power_status(&reply, reply_pwr);
+	cec_transmit_msg(input_adap, &reply, false);
+}
+
+/* Transmit Give Device Power Status to all output ports */
+static int cec_out_give_device_power_status(struct cec_splitter *splitter)
+{
+	ktime_t now = ktime_get();
+	bool error = true;
+	unsigned int i;
+
+	for (i = 0; i < splitter->num_out_ports; i++) {
+		struct cec_splitter_port *p = splitter->ports[i];
+		struct cec_adapter *adap = p->adap;
+
+		/*
+		 * Keep the old ts if an earlier request is still
+		 * pending. This ensures that the request will
+		 * eventually time out based on the timestamp of
+		 * the first request if the sink is unresponsive.
+		 */
+		if (adap->is_configured && !p->out_give_device_power_status_seq)
+			p->out_give_device_power_status_ts = now;
+	}
+
+	for (i = 0; i < splitter->num_out_ports; i++) {
+		struct cec_splitter_port *p = splitter->ports[i];
+		struct cec_adapter *adap = p->adap;
+		struct cec_msg msg;
+
+		if (!adap->is_configured)
+			continue;
+
+		cec_msg_init(&msg, adap->log_addrs.log_addr[0], 0);
+		cec_msg_give_device_power_status(&msg, true);
+		if (cec_transmit_msg(adap, &msg, false))
+			continue;
+		p->out_give_device_power_status_seq = msg.sequence | (1U << 31);
+		error = false;
+	}
+	return error ? -ENODEV : 0;
+}
+
+/*
+ * CEC messages received on the HDMI input of the splitter are
+ * forwarded (if relevant) to the HDMI outputs of the splitter.
+ */
+int cec_splitter_received_input(struct cec_splitter_port *p, struct cec_msg *msg)
+{
+	if (!cec_msg_status_is_ok(msg))
+		return 0;
+
+	if (msg->len < 2)
+		return -ENOMSG;
+
+	switch (msg->msg[1]) {
+	case CEC_MSG_DEVICE_VENDOR_ID:
+	case CEC_MSG_REPORT_POWER_STATUS:
+	case CEC_MSG_SET_STREAM_PATH:
+	case CEC_MSG_ROUTING_CHANGE:
+	case CEC_MSG_REQUEST_ACTIVE_SOURCE:
+	case CEC_MSG_SYSTEM_AUDIO_MODE_STATUS:
+		return 0;
+
+	case CEC_MSG_STANDBY:
+		p->splitter->is_standby = true;
+		cec_out_standby(p->splitter);
+		return 0;
+
+	case CEC_MSG_IMAGE_VIEW_ON:
+	case CEC_MSG_TEXT_VIEW_ON:
+		p->splitter->is_standby = false;
+		cec_out_wakeup(p->splitter, msg->msg[1]);
+		return 0;
+
+	case CEC_MSG_ACTIVE_SOURCE:
+		cec_out_active_source(p->splitter);
+		return 0;
+
+	case CEC_MSG_SET_SYSTEM_AUDIO_MODE:
+		cec_out_passthrough(p->splitter, msg);
+		return 0;
+
+	case CEC_MSG_GIVE_DEVICE_POWER_STATUS:
+		p->splitter->give_device_power_status_dest =
+			cec_msg_initiator(msg);
+		if (cec_out_give_device_power_status(p->splitter))
+			cec_feature_abort_reason(p->adap, msg,
+						 CEC_OP_ABORT_INCORRECT_MODE);
+		return 0;
+
+	case CEC_MSG_REQUEST_CURRENT_LATENCY: {
+		u16 pa;
+
+		p->splitter->request_current_latency_dest =
+			cec_msg_initiator(msg);
+		cec_ops_request_current_latency(msg, &pa);
+		if (pa == p->adap->phys_addr &&
+		    cec_out_request_current_latency(p->splitter))
+			cec_feature_abort_reason(p->adap, msg,
+						 CEC_OP_ABORT_INCORRECT_MODE);
+		return 0;
+	}
+
+	default:
+		return -ENOMSG;
+	}
+	return -ENOMSG;
+}
+
+void cec_splitter_nb_transmit_canceled_output(struct cec_splitter_port *p,
+					      const struct cec_msg *msg,
+					      struct cec_adapter *input_adap)
+{
+	struct cec_splitter *splitter = p->splitter;
+	u32 seq = msg->sequence | (1U << 31);
+
+	/*
+	 * If this is the result of a failed non-blocking transmit, or it is
+	 * the result of the failed reply to a non-blocking transmit, then
+	 * check if the original transmit was to get the current power status
+	 * or latency and, if so, assume that the remove device is for one
+	 * reason or another unavailable and assume that it is in the same
+	 * power status as the splitter, or has no video latency.
+	 */
+	if ((cec_msg_recv_is_tx_result(msg) && !(msg->tx_status & CEC_TX_STATUS_OK)) ||
+	    (cec_msg_recv_is_rx_result(msg) && !(msg->rx_status & CEC_RX_STATUS_OK))) {
+		u8 tx_op = msg->msg[1];
+
+		if (msg->len < 2)
+			return;
+		if (cec_msg_recv_is_rx_result(msg) &&
+		    (msg->rx_status & CEC_RX_STATUS_FEATURE_ABORT))
+			tx_op = msg->msg[2];
+		switch (tx_op) {
+		case CEC_MSG_GIVE_DEVICE_POWER_STATUS:
+			if (p->out_give_device_power_status_seq != seq)
+				break;
+			p->out_give_device_power_status_seq = 0;
+			p->out_give_device_power_status_ts = ktime_set(0, 0);
+			p->power_status = splitter->is_standby ?
+					  CEC_OP_POWER_STATUS_STANDBY :
+					  CEC_OP_POWER_STATUS_ON;
+			cec_out_report_power_status(splitter, input_adap);
+			break;
+		case CEC_MSG_REQUEST_CURRENT_LATENCY:
+			if (p->out_request_current_latency_seq != seq)
+				break;
+			p->video_latency = 1;
+			p->out_request_current_latency_seq = 0;
+			p->out_request_current_latency_ts = ktime_set(0, 0);
+			cec_out_report_current_latency(splitter, input_adap);
+			break;
+		}
+		return;
+	}
+
+	if (cec_msg_recv_is_tx_result(msg)) {
+		if (p->out_request_current_latency_seq != seq)
+			return;
+		p->out_request_current_latency_ts = ns_to_ktime(msg->tx_ts);
+		return;
+	}
+}
+
+/*
+ * CEC messages received on an HDMI output of the splitter
+ * are processed here.
+ */
+int cec_splitter_received_output(struct cec_splitter_port *p, struct cec_msg *msg,
+				 struct cec_adapter *input_adap)
+{
+	struct cec_adapter *adap = p->adap;
+	struct cec_splitter *splitter = p->splitter;
+	u32 seq = msg->sequence | (1U << 31);
+	struct cec_msg reply = {};
+	u16 pa;
+
+	if (!adap->is_configured || msg->len < 2)
+		return -ENOMSG;
+
+	switch (msg->msg[1]) {
+	case CEC_MSG_REPORT_POWER_STATUS: {
+		u8 pwr;
+
+		cec_ops_report_power_status(msg, &pwr);
+		if (pwr > CEC_OP_POWER_STATUS_TO_STANDBY)
+			pwr = splitter->is_standby ?
+				CEC_OP_POWER_STATUS_TO_STANDBY :
+				CEC_OP_POWER_STATUS_TO_ON;
+		p->power_status = pwr;
+		if (p->out_give_device_power_status_seq == seq) {
+			p->out_give_device_power_status_seq = 0;
+			p->out_give_device_power_status_ts = ktime_set(0, 0);
+		}
+		cec_out_report_power_status(splitter, input_adap);
+		return 0;
+	}
+
+	case CEC_MSG_REPORT_CURRENT_LATENCY: {
+		u8 video_lat;
+		u8 low_lat_mode;
+		u8 audio_out_comp;
+		u8 audio_out_delay;
+
+		cec_ops_report_current_latency(msg, &pa,
+					       &video_lat, &low_lat_mode,
+					       &audio_out_comp, &audio_out_delay);
+		if (!video_lat || video_lat >= 252)
+			video_lat = 1;
+		p->video_latency = video_lat;
+		if (p->out_request_current_latency_seq == seq) {
+			p->out_request_current_latency_seq = 0;
+			p->out_request_current_latency_ts = ktime_set(0, 0);
+		}
+		cec_out_report_current_latency(splitter, input_adap);
+		return 0;
+	}
+
+	case CEC_MSG_STANDBY:
+	case CEC_MSG_ROUTING_CHANGE:
+	case CEC_MSG_GIVE_SYSTEM_AUDIO_MODE_STATUS:
+		return 0;
+
+	case CEC_MSG_ACTIVE_SOURCE:
+		cec_ops_active_source(msg, &pa);
+		if (pa == 0)
+			p->is_active_source = false;
+		return 0;
+
+	case CEC_MSG_REQUEST_ACTIVE_SOURCE:
+		if (!p->is_active_source)
+			return 0;
+		cec_msg_set_reply_to(&reply, msg);
+		cec_msg_active_source(&reply, adap->phys_addr);
+		cec_transmit_msg(adap, &reply, false);
+		return 0;
+
+	case CEC_MSG_GIVE_DEVICE_POWER_STATUS:
+		cec_msg_set_reply_to(&reply, msg);
+		cec_msg_report_power_status(&reply, splitter->is_standby ?
+					    CEC_OP_POWER_STATUS_STANDBY :
+					    CEC_OP_POWER_STATUS_ON);
+		cec_transmit_msg(adap, &reply, false);
+		return 0;
+
+	case CEC_MSG_SET_STREAM_PATH:
+		cec_ops_set_stream_path(msg, &pa);
+		if (pa == adap->phys_addr) {
+			cec_msg_set_reply_to(&reply, msg);
+			cec_msg_active_source(&reply, pa);
+			cec_transmit_msg(adap, &reply, false);
+		}
+		return 0;
+
+	default:
+		return -ENOMSG;
+	}
+	return -ENOMSG;
+}
+
+/*
+ * Called every second to check for timed out messages and whether there
+ * still is a video sink connected or not.
+ *
+ * Returns true if sinks were lost.
+ */
+bool cec_splitter_poll(struct cec_splitter *splitter,
+		       struct cec_adapter *input_adap, bool debug)
+{
+	ktime_t now = ktime_get();
+	u8 pwr = splitter->is_standby ?
+		 CEC_OP_POWER_STATUS_STANDBY : CEC_OP_POWER_STATUS_ON;
+	unsigned int max_delay_ms = input_adap->xfer_timeout_ms + 2000;
+	unsigned int i;
+	bool res = false;
+
+	for (i = 0; i < splitter->num_out_ports; i++) {
+		struct cec_splitter_port *p = splitter->ports[i];
+		s64 pwr_delta, lat_delta;
+		bool pwr_timeout, lat_timeout;
+
+		if (!p)
+			continue;
+
+		pwr_delta = ktime_ms_delta(now, p->out_give_device_power_status_ts);
+		pwr_timeout = p->out_give_device_power_status_seq &&
+			      pwr_delta >= max_delay_ms;
+		lat_delta = ktime_ms_delta(now, p->out_request_current_latency_ts);
+		lat_timeout = p->out_request_current_latency_seq &&
+			      lat_delta >= max_delay_ms;
+
+		/*
+		 * If the HPD is low for more than 5 seconds, then assume no display
+		 * is connected.
+		 */
+		if (p->found_sink && ktime_to_ns(p->lost_sink_ts) &&
+		    ktime_ms_delta(now, p->lost_sink_ts) > 5000) {
+			if (debug)
+				dev_info(splitter->dev,
+					 "port %u: HPD low for more than 5s, assume no sink is connected.\n",
+					 p->port);
+			p->found_sink = false;
+			p->lost_sink_ts = ktime_set(0, 0);
+			res = true;
+		}
+
+		/*
+		 * If the power status request timed out, then set the port's
+		 * power status to that of the splitter, ensuring a consistent
+		 * power state.
+		 */
+		if (pwr_timeout) {
+			mutex_lock(&p->adap->lock);
+			if (debug)
+				dev_info(splitter->dev,
+					 "port %u: give up on power status for seq %u\n",
+					 p->port,
+					 p->out_give_device_power_status_seq & ~(1 << 31));
+			p->power_status = pwr;
+			p->out_give_device_power_status_seq = 0;
+			p->out_give_device_power_status_ts = ktime_set(0, 0);
+			mutex_unlock(&p->adap->lock);
+			cec_out_report_power_status(splitter, input_adap);
+		}
+
+		/*
+		 * If the current latency request timed out, then set the port's
+		 * latency to 1.
+		 */
+		if (lat_timeout) {
+			mutex_lock(&p->adap->lock);
+			if (debug)
+				dev_info(splitter->dev,
+					 "port %u: give up on latency for seq %u\n",
+					 p->port,
+					 p->out_request_current_latency_seq & ~(1 << 31));
+			p->video_latency = 1;
+			p->out_request_current_latency_seq = 0;
+			p->out_request_current_latency_ts = ktime_set(0, 0);
+			mutex_unlock(&p->adap->lock);
+			cec_out_report_current_latency(splitter, input_adap);
+		}
+	}
+	return res;
+}
diff --git a/drivers/media/cec/usb/extron-da-hd-4k-plus/cec-splitter.h b/drivers/media/cec/usb/extron-da-hd-4k-plus/cec-splitter.h
new file mode 100644
index 000000000000..7422f7c5719e
--- /dev/null
+++ b/drivers/media/cec/usb/extron-da-hd-4k-plus/cec-splitter.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+/*
+ * Copyright 2021-2024 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ */
+
+#ifndef _CEC_SPLITTER_H_
+#define _CEC_SPLITTER_H_
+
+struct cec_splitter;
+
+#define STATE_CHANGE_MAX_REPEATS 2
+
+struct cec_splitter_port {
+	struct cec_splitter *splitter;
+	struct cec_adapter *adap;
+	unsigned int port;
+	bool is_active_source;
+	bool found_sink;
+	ktime_t lost_sink_ts;
+	u32 out_request_current_latency_seq;
+	ktime_t out_request_current_latency_ts;
+	u8 video_latency;
+	u32 out_give_device_power_status_seq;
+	ktime_t out_give_device_power_status_ts;
+	u8 power_status;
+};
+
+struct cec_splitter {
+	struct device *dev;
+	unsigned int num_out_ports;
+	struct cec_splitter_port **ports;
+
+	/* High-level splitter state */
+	u8 request_current_latency_dest;
+	u8 give_device_power_status_dest;
+	bool is_standby;
+};
+
+void cec_splitter_unconfigured_output(struct cec_splitter_port *port);
+void cec_splitter_configured_output(struct cec_splitter_port *port);
+int cec_splitter_received_input(struct cec_splitter_port *port, struct cec_msg *msg);
+int cec_splitter_received_output(struct cec_splitter_port *port, struct cec_msg *msg,
+				 struct cec_adapter *input_adap);
+void cec_splitter_nb_transmit_canceled_output(struct cec_splitter_port *port,
+					      const struct cec_msg *msg,
+					      struct cec_adapter *input_adap);
+bool cec_splitter_poll(struct cec_splitter *splitter,
+		       struct cec_adapter *input_adap, bool debug);
+
+#endif
diff --git a/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c b/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c
new file mode 100644
index 000000000000..8526f613a40e
--- /dev/null
+++ b/drivers/media/cec/usb/extron-da-hd-4k-plus/extron-da-hd-4k-plus.c
@@ -0,0 +1,1836 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2021-2024 Cisco Systems, Inc. and/or its affiliates. All rights reserved.
+ */
+
+/*
+ * Currently this driver does not fully support the serial port of the
+ * Extron, only the USB port is fully supported.
+ *
+ * Issues specific to using the serial port instead of the USB since the
+ * serial port doesn't detect if the device is powered off:
+ *
+ * - Some periodic ping mechanism is needed to detect when the Extron is
+ *   powered off and when it is powered on again.
+ * - What to do when it is powered off and the driver is modprobed? Keep
+ *   trying to contact the Extron indefinitely?
+ */
+
+#include <linux/completion.h>
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+
+#include "extron-da-hd-4k-plus.h"
+
+MODULE_AUTHOR("Hans Verkuil <hansverk@cisco.com>");
+MODULE_DESCRIPTION("Extron DA HD 4K PLUS HDMI CEC driver");
+MODULE_LICENSE("GPL");
+
+static int debug;
+module_param(debug, int, 0644);
+MODULE_PARM_DESC(debug, "debug level (0-1)");
+
+static unsigned int vendor_id;
+module_param(vendor_id, uint, 0444);
+MODULE_PARM_DESC(vendor_id, "CEC Vendor ID");
+
+static char manufacturer_name[4];
+module_param_string(manufacturer_name, manufacturer_name,
+		    sizeof(manufacturer_name), 0644);
+MODULE_PARM_DESC(manufacturer_name,
+		 "EDID Vendor String (3 uppercase characters)");
+
+static bool hpd_never_low;
+module_param(hpd_never_low, bool, 0644);
+MODULE_PARM_DESC(hpd_never_low, "Input HPD will never go low (1), or go low if all output HPDs are low (0, default)");
+
+#define EXTRON_TIMEOUT_SECS 6
+
+static const u8 hdmi_edid[256] = {
+	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00,
+	0x31, 0xd8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x01, 0x20, 0x01, 0x03, 0x80, 0x60, 0x36, 0x78,
+	0x0f, 0xee, 0x91, 0xa3, 0x54, 0x4c, 0x99, 0x26,
+	0x0f, 0x50, 0x54, 0x20, 0x00, 0x00, 0x01, 0x01,
+	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x02, 0x3a,
+	0x80, 0x18, 0x71, 0x38, 0x2d, 0x40, 0x58, 0x2c,
+	0x45, 0x00, 0xc0, 0x1c, 0x32, 0x00, 0x00, 0x1e,
+	0x00, 0x00, 0x00, 0xfd, 0x00, 0x18, 0x55, 0x18,
+	0x87, 0x11, 0x00, 0x0a, 0x20, 0x20, 0x20, 0x20,
+	0x20, 0x20, 0x00, 0x00, 0x00, 0xfc, 0x00, 0x68,
+	0x64, 0x6d, 0x69, 0x2d, 0x31, 0x30, 0x38, 0x30,
+	0x70, 0x36, 0x30, 0x0a, 0x00, 0x00, 0x00, 0xfe,
+	0x00, 0x73, 0x65, 0x72, 0x69, 0x6f, 0x0a, 0x20,
+	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x01, 0x95,
+
+	0x02, 0x03, 0x1b, 0xf1, 0x42, 0x10, 0x01, 0x23,
+	0x09, 0x07, 0x07, 0x83, 0x01, 0x00, 0x00, 0x68,
+	0x03, 0x0c, 0x00, 0x10, 0x00, 0x00, 0x21, 0x01,
+	0xe2, 0x00, 0xca, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x89,
+};
+
+static const u8 hdmi_edid_4k_300[256] = {
+	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00,
+	0x31, 0xd8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x01, 0x20, 0x01, 0x03, 0x80, 0x60, 0x36, 0x78,
+	0x0f, 0xee, 0x91, 0xa3, 0x54, 0x4c, 0x99, 0x26,
+	0x0f, 0x50, 0x54, 0x20, 0x00, 0x00, 0x01, 0x01,
+	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x02, 0x3a,
+	0x80, 0x18, 0x71, 0x38, 0x2d, 0x40, 0x58, 0x2c,
+	0x45, 0x00, 0xc0, 0x1c, 0x32, 0x00, 0x00, 0x1e,
+	0x00, 0x00, 0x00, 0xfd, 0x00, 0x18, 0x55, 0x18,
+	0x87, 0x3c, 0x00, 0x0a, 0x20, 0x20, 0x20, 0x20,
+	0x20, 0x20, 0x00, 0x00, 0x00, 0xfc, 0x00, 0x68,
+	0x64, 0x6d, 0x69, 0x2d, 0x34, 0x6b, 0x2d, 0x36,
+	0x30, 0x30, 0x0a, 0x20, 0x00, 0x00, 0x00, 0xfe,
+	0x00, 0x73, 0x65, 0x72, 0x69, 0x6f, 0x0a, 0x20,
+	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x01, 0x87,
+
+	0x02, 0x03, 0x1f, 0xf1, 0x43, 0x10, 0x5f, 0x01,
+	0x23, 0x09, 0x07, 0x07, 0x83, 0x01, 0x00, 0x00,
+	0x6b, 0x03, 0x0c, 0x00, 0x10, 0x00, 0x00, 0x3c,
+	0x21, 0x00, 0x20, 0x01, 0xe2, 0x00, 0xca, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xc6,
+};
+
+static const u8 hdmi_edid_4k_600[256] = {
+	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00,
+	0x31, 0xd8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x01, 0x20, 0x01, 0x03, 0x80, 0x60, 0x36, 0x78,
+	0x0f, 0xee, 0x91, 0xa3, 0x54, 0x4c, 0x99, 0x26,
+	0x0f, 0x50, 0x54, 0x20, 0x00, 0x00, 0x01, 0x01,
+	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
+	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x08, 0xe8,
+	0x00, 0x30, 0xf2, 0x70, 0x5a, 0x80, 0xb0, 0x58,
+	0x8a, 0x00, 0xc0, 0x1c, 0x32, 0x00, 0x00, 0x1e,
+	0x00, 0x00, 0x00, 0xfd, 0x00, 0x18, 0x55, 0x18,
+	0x87, 0x3c, 0x00, 0x0a, 0x20, 0x20, 0x20, 0x20,
+	0x20, 0x20, 0x00, 0x00, 0x00, 0xfc, 0x00, 0x68,
+	0x64, 0x6d, 0x69, 0x2d, 0x34, 0x6b, 0x2d, 0x36,
+	0x30, 0x30, 0x0a, 0x20, 0x00, 0x00, 0x00, 0xfe,
+	0x00, 0x73, 0x65, 0x72, 0x69, 0x6f, 0x0a, 0x20,
+	0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x01, 0x4c,
+
+	0x02, 0x03, 0x28, 0xf1, 0x44, 0x61, 0x5f, 0x10,
+	0x01, 0x23, 0x09, 0x07, 0x07, 0x83, 0x01, 0x00,
+	0x00, 0x6b, 0x03, 0x0c, 0x00, 0x10, 0x00, 0x00,
+	0x3c, 0x21, 0x00, 0x20, 0x01, 0x67, 0xd8, 0x5d,
+	0xc4, 0x01, 0x78, 0x00, 0x00, 0xe2, 0x00, 0xca,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x82,
+};
+
+static int extron_send_byte(struct serio *serio, char byte)
+{
+	int err, i;
+
+	for (i = 0; i < 100; i++) {
+		err = serio_write(serio, byte);
+		if (!err)
+			break;
+		usleep_range(80, 120);
+	}
+	if (err)
+		dev_warn(&serio->dev, "unable to write