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Subject: Re: [PATCH v5 15/15] ipu3-cio2: Add cio2-bridge to ipu3-cio2 driver
From:   Daniel Scally <djrscally@gmail.com>
To:     linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
        linux-media@vger.kernel.org, devel@acpica.org, rjw@rjwysocki.net,
        lenb@kernel.org, gregkh@linuxfoundation.org, mchehab@kernel.org,
        sergey.senozhatsky@gmail.com
Cc:     yong.zhi@intel.com, sakari.ailus@linux.intel.com,
        bingbu.cao@intel.com, tian.shu.qiu@intel.com,
        robert.moore@intel.com, erik.kaneda@intel.com, pmladek@suse.com,
        rostedt@goodmis.org, andriy.shevchenko@linux.intel.com,
        linux@rasmusvillemoes.dk,
        laurent.pinchart+renesas@ideasonboard.com,
        jacopo+renesas@jmondi.org, kieran.bingham+renesas@ideasonboard.com,
        hverkuil-cisco@xs4all.nl, m.felsch@pengutronix.de,
        niklas.soderlund+renesas@ragnatech.se,
        prabhakar.mahadev-lad.rj@bp.renesas.com, slongerbeam@gmail.com,
        heikki.krogerus@linux.intel.com,
        Jordan Hand <jorhand@linux.microsoft.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Kieran Bingham <kieran.bingham@ideasonboard.com>
References: <20210107132838.396641-1-djrscally@gmail.com>
 <20210107132838.396641-16-djrscally@gmail.com>
Message-ID: <e04c984e-75fd-1acf-f65f-5d19303bded7@gmail.com>
Date:   Thu, 7 Jan 2021 14:07:41 +0000
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On 07/01/2021 13:28, Daniel Scally wrote:
> Currently on platforms designed for Windows, connections between CIO2 and
> sensors are not properly defined in DSDT. This patch extends the ipu3-cio2
> driver to compensate by building software_node connections, parsing the
> connection properties from the sensor's SSDB buffer.
> 
> Suggested-by: Jordan Hand <jorhand@linux.microsoft.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
> Signed-off-by: Daniel Scally <djrscally@gmail.com>
> ---

Sorry all, missed the changelog on this one:

---
Changes in v5:

	- Changed some macros to declare compound literals
	- Switched cio2_check_fwnode_graph() to return int instead of bool
	- Added some comments to clarify parts of the code that might look
	  weird initially
	- Some cosmetic changes


>  MAINTAINERS                                   |   1 +
>  drivers/media/pci/intel/ipu3/Kconfig          |  18 +
>  drivers/media/pci/intel/ipu3/Makefile         |   1 +
>  drivers/media/pci/intel/ipu3/cio2-bridge.c    | 311 ++++++++++++++++++
>  drivers/media/pci/intel/ipu3/cio2-bridge.h    | 125 +++++++
>  drivers/media/pci/intel/ipu3/ipu3-cio2-main.c |  34 ++
>  drivers/media/pci/intel/ipu3/ipu3-cio2.h      |   6 +
>  7 files changed, 496 insertions(+)
>  create mode 100644 drivers/media/pci/intel/ipu3/cio2-bridge.c
>  create mode 100644 drivers/media/pci/intel/ipu3/cio2-bridge.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 92228e8dd868..a091b496fdd8 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9014,6 +9014,7 @@ INTEL IPU3 CSI-2 CIO2 DRIVER
>  M:	Yong Zhi <yong.zhi@intel.com>
>  M:	Sakari Ailus <sakari.ailus@linux.intel.com>
>  M:	Bingbu Cao <bingbu.cao@intel.com>
> +M:	Dan Scally <djrscally@gmail.com>
>  R:	Tianshu Qiu <tian.shu.qiu@intel.com>
>  L:	linux-media@vger.kernel.org
>  S:	Maintained
> diff --git a/drivers/media/pci/intel/ipu3/Kconfig b/drivers/media/pci/intel/ipu3/Kconfig
> index 82d7f17e6a02..96a2231b16ad 100644
> --- a/drivers/media/pci/intel/ipu3/Kconfig
> +++ b/drivers/media/pci/intel/ipu3/Kconfig
> @@ -16,3 +16,21 @@ config VIDEO_IPU3_CIO2
>  	  Say Y or M here if you have a Skylake/Kaby Lake SoC with MIPI CSI-2
>  	  connected camera.
>  	  The module will be called ipu3-cio2.
> +
> +config CIO2_BRIDGE
> +	bool "IPU3 CIO2 Sensors Bridge"
> +	depends on VIDEO_IPU3_CIO2
> +	help
> +	  This extension provides an API for the ipu3-cio2 driver to create
> +	  connections to cameras that are hidden in the SSDB buffer in ACPI.
> +	  It can be used to enable support for cameras in detachable / hybrid
> +	  devices that ship with Windows.
> +
> +	  Say Y here if your device is a detachable / hybrid laptop that comes
> +	  with Windows installed by the OEM, for example:
> +
> +		- Microsoft Surface models (except Surface Pro 3)
> +		- The Lenovo Miix line (for example the 510, 520, 710 and 720)
> +		- Dell 7285
> +
> +	  If in doubt, say N here.
> diff --git a/drivers/media/pci/intel/ipu3/Makefile b/drivers/media/pci/intel/ipu3/Makefile
> index 429d516452e4..933777e6ea8a 100644
> --- a/drivers/media/pci/intel/ipu3/Makefile
> +++ b/drivers/media/pci/intel/ipu3/Makefile
> @@ -2,3 +2,4 @@
>  obj-$(CONFIG_VIDEO_IPU3_CIO2) += ipu3-cio2.o
>  
>  ipu3-cio2-y += ipu3-cio2-main.o
> +ipu3-cio2-$(CONFIG_CIO2_BRIDGE) += cio2-bridge.o
> diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.c b/drivers/media/pci/intel/ipu3/cio2-bridge.c
> new file mode 100644
> index 000000000000..143f3c0f445e
> --- /dev/null
> +++ b/drivers/media/pci/intel/ipu3/cio2-bridge.c
> @@ -0,0 +1,311 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Author: Dan Scally <djrscally@gmail.com> */
> +
> +#include <linux/acpi.h>
> +#include <linux/device.h>
> +#include <linux/pci.h>
> +#include <linux/property.h>
> +#include <media/v4l2-fwnode.h>
> +
> +#include "cio2-bridge.h"
> +
> +/*
> + * Extend this array with ACPI Hardware IDs of devices known to be working
> + * plus the number of link-frequencies expected by their drivers, along with
> + * the frequency values in hertz. This is somewhat opportunistic way of adding
> + * support for this for now in the hopes of a better source for the information
> + * (possibly some encoded value in the SSDB buffer that we're unaware of)
> + * becoming apparent in the future.
> + *
> + * Do not add an entry for a sensor that is not actually supported.
> + */
> +static const struct cio2_sensor_config cio2_supported_sensors[] = {
> +	/* Omnivision OV5693 */
> +	CIO2_SENSOR_CONFIG("INT33BE", 0),
> +	/* Omnivision OV2680 */
> +	CIO2_SENSOR_CONFIG("OVTI2680", 0),
> +};
> +
> +static const struct cio2_property_names prop_names = {
> +	.clock_frequency = "clock-frequency",
> +	.rotation = "rotation",
> +	.bus_type = "bus-type",
> +	.data_lanes = "data-lanes",
> +	.remote_endpoint = "remote-endpoint",
> +	.link_frequencies = "link-frequencies",
> +};
> +
> +static int cio2_bridge_read_acpi_buffer(struct acpi_device *adev, char *id,
> +					void *data, u32 size)
> +{
> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +	union acpi_object *obj;
> +	acpi_status status;
> +	int ret = 0;
> +
> +	status = acpi_evaluate_object(adev->handle, id, NULL, &buffer);
> +	if (ACPI_FAILURE(status))
> +		return -ENODEV;
> +
> +	obj = buffer.pointer;
> +	if (!obj) {
> +		dev_err(&adev->dev, "Couldn't locate ACPI buffer\n");
> +		return -ENODEV;
> +	}
> +
> +	if (obj->type != ACPI_TYPE_BUFFER) {
> +		dev_err(&adev->dev, "Not an ACPI buffer\n");
> +		ret = -ENODEV;
> +		goto out_free_buff;
> +	}
> +
> +	if (obj->buffer.length > size) {
> +		dev_err(&adev->dev, "Given buffer is too small\n");
> +		ret = -EINVAL;
> +		goto out_free_buff;
> +	}
> +
> +	memcpy(data, obj->buffer.pointer, obj->buffer.length);
> +
> +out_free_buff:
> +	kfree(buffer.pointer);
> +	return ret;
> +}
> +
> +static void cio2_bridge_create_fwnode_properties(
> +	struct cio2_sensor *sensor,
> +	struct cio2_bridge *bridge,
> +	const struct cio2_sensor_config *cfg)
> +{
> +	sensor->prop_names = prop_names;
> +
> +	sensor->local_ref[0].node = &sensor->swnodes[SWNODE_CIO2_ENDPOINT];
> +	sensor->remote_ref[0].node = &sensor->swnodes[SWNODE_SENSOR_ENDPOINT];
> +
> +	sensor->dev_properties[0] = PROPERTY_ENTRY_U32(
> +					sensor->prop_names.clock_frequency,
> +					sensor->ssdb.mclkspeed);
> +	sensor->dev_properties[1] = PROPERTY_ENTRY_U8(
> +					sensor->prop_names.rotation,
> +					sensor->ssdb.degree);
> +
> +	sensor->ep_properties[0] = PROPERTY_ENTRY_U32(
> +					sensor->prop_names.bus_type,
> +					V4L2_FWNODE_BUS_TYPE_CSI2_DPHY);
> +	sensor->ep_properties[1] = PROPERTY_ENTRY_U32_ARRAY_LEN(
> +					sensor->prop_names.data_lanes,
> +					bridge->data_lanes,
> +					sensor->ssdb.lanes);
> +	sensor->ep_properties[2] = PROPERTY_ENTRY_REF_ARRAY(
> +					sensor->prop_names.remote_endpoint,
> +					sensor->local_ref);
> +
> +	if (cfg->nr_link_freqs > 0)
> +		sensor->ep_properties[3] = PROPERTY_ENTRY_U64_ARRAY_LEN(
> +						sensor->prop_names.link_frequencies,
> +						cfg->link_freqs,
> +						cfg->nr_link_freqs);
> +
> +	sensor->cio2_properties[0] = PROPERTY_ENTRY_U32_ARRAY_LEN(
> +					sensor->prop_names.data_lanes,
> +					bridge->data_lanes,
> +					sensor->ssdb.lanes);
> +	sensor->cio2_properties[1] = PROPERTY_ENTRY_REF_ARRAY(
> +					sensor->prop_names.remote_endpoint,
> +					sensor->remote_ref);
> +}
> +
> +static void cio2_bridge_init_swnode_names(struct cio2_sensor *sensor)
> +{
> +	snprintf(sensor->node_names.remote_port,
> +		 sizeof(sensor->node_names.remote_port),
> +		 SWNODE_GRAPH_PORT_NAME_FMT, sensor->ssdb.link);
> +	snprintf(sensor->node_names.port,
> +		 sizeof(sensor->node_names.port),
> +		 SWNODE_GRAPH_PORT_NAME_FMT, 0); /* Always port 0 */
> +	snprintf(sensor->node_names.endpoint,
> +		 sizeof(sensor->node_names.endpoint),
> +		 SWNODE_GRAPH_ENDPOINT_NAME_FMT, 0); /* And endpoint 0 */
> +}
> +
> +static void cio2_bridge_create_connection_swnodes(struct cio2_bridge *bridge,
> +						  struct cio2_sensor *sensor)
> +{
> +	struct software_node *nodes = sensor->swnodes;
> +
> +	cio2_bridge_init_swnode_names(sensor);
> +
> +	nodes[SWNODE_SENSOR_HID] = NODE_SENSOR(sensor->name,
> +					       sensor->dev_properties);
> +	nodes[SWNODE_SENSOR_PORT] = NODE_PORT(sensor->node_names.port,
> +					      &nodes[SWNODE_SENSOR_HID]);
> +	nodes[SWNODE_SENSOR_ENDPOINT] = NODE_ENDPOINT(
> +						sensor->node_names.endpoint,
> +						&nodes[SWNODE_SENSOR_PORT],
> +						sensor->ep_properties);
> +	nodes[SWNODE_CIO2_PORT] = NODE_PORT(sensor->node_names.remote_port,
> +					    &bridge->cio2_hid_node);
> +	nodes[SWNODE_CIO2_ENDPOINT] = NODE_ENDPOINT(
> +						sensor->node_names.endpoint,
> +						&nodes[SWNODE_CIO2_PORT],
> +						sensor->cio2_properties);
> +}
> +
> +static void cio2_bridge_unregister_sensors(struct cio2_bridge *bridge)
> +{
> +	struct cio2_sensor *sensor;
> +	unsigned int i;
> +
> +	for (i = 0; i < bridge->n_sensors; i++) {
> +		sensor = &bridge->sensors[i];
> +		software_node_unregister_nodes(sensor->swnodes);
> +		acpi_dev_put(sensor->adev);
> +	}
> +}
> +
> +static int cio2_bridge_connect_sensor(const struct cio2_sensor_config *cfg,
> +				      struct cio2_bridge *bridge,
> +				      struct pci_dev *cio2)
> +{
> +	struct fwnode_handle *fwnode;
> +	struct cio2_sensor *sensor;
> +	struct acpi_device *adev;
> +	int ret;
> +
> +	for_each_acpi_dev_match(adev, cfg->hid, NULL, -1) {
> +		if (!adev->status.enabled)
> +			continue;
> +
> +		if (bridge->n_sensors >= CIO2_NUM_PORTS) {
> +			dev_err(&cio2->dev, "Exceeded available CIO2 ports\n");
> +			cio2_bridge_unregister_sensors(bridge);
> +			ret = -EINVAL;
> +			goto err_out;
> +		}
> +
> +		sensor = &bridge->sensors[bridge->n_sensors];
> +		sensor->adev = adev;
> +		strscpy(sensor->name, cfg->hid, sizeof(sensor->name));
> +
> +		ret = cio2_bridge_read_acpi_buffer(adev, "SSDB",
> +						   &sensor->ssdb,
> +						   sizeof(sensor->ssdb));
> +		if (ret)
> +			goto err_put_adev;
> +
> +		if (sensor->ssdb.lanes > CIO2_MAX_LANES) {
> +			dev_err(&adev->dev,
> +				"Number of lanes in SSDB is invalid\n");
> +			ret = -EINVAL;
> +			goto err_put_adev;
> +		}
> +
> +		cio2_bridge_create_fwnode_properties(sensor, bridge, cfg);
> +		cio2_bridge_create_connection_swnodes(bridge, sensor);
> +
> +		ret = software_node_register_nodes(sensor->swnodes);
> +		if (ret)
> +			goto err_put_adev;
> +
> +		fwnode = software_node_fwnode(&sensor->swnodes[SWNODE_SENSOR_HID]);
> +		if (!fwnode) {
> +			ret = -ENODEV;
> +			goto err_free_swnodes;
> +		}
> +
> +		adev->fwnode.secondary = fwnode;
> +
> +		dev_info(&cio2->dev, "Found supported sensor %s\n",
> +			 acpi_dev_name(adev));
> +
> +		bridge->n_sensors++;
> +	}
> +
> +	return 0;
> +
> +err_free_swnodes:
> +	software_node_unregister_nodes(sensor->swnodes);
> +err_put_adev:
> +	acpi_dev_put(sensor->adev);
> +err_out:
> +	return ret;
> +}
> +
> +static int cio2_bridge_connect_sensors(struct cio2_bridge *bridge,
> +				       struct pci_dev *cio2)
> +{
> +	unsigned int i;
> +	int ret;
> +
> +	for (i = 0; i < ARRAY_SIZE(cio2_supported_sensors); i++) {
> +		const struct cio2_sensor_config *cfg = &cio2_supported_sensors[i];
> +
> +		ret = cio2_bridge_connect_sensor(cfg, bridge, cio2);
> +		if (ret)
> +			goto err_unregister_sensors;
> +	}
> +
> +	return 0;
> +
> +err_unregister_sensors:
> +	cio2_bridge_unregister_sensors(bridge);
> +	return ret;
> +}
> +
> +int cio2_bridge_init(struct pci_dev *cio2)
> +{
> +	struct device *dev = &cio2->dev;
> +	struct fwnode_handle *fwnode;
> +	struct cio2_bridge *bridge;
> +	unsigned int i;
> +	int ret;
> +
> +	bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
> +	if (!bridge)
> +		return -ENOMEM;
> +
> +	strscpy(bridge->cio2_node_name, CIO2_HID, sizeof(bridge->cio2_node_name));
> +	bridge->cio2_hid_node.name = bridge->cio2_node_name;
> +
> +	ret = software_node_register(&bridge->cio2_hid_node);
> +	if (ret < 0) {
> +		dev_err(dev, "Failed to register the CIO2 HID node\n");
> +		goto err_free_bridge;
> +	}
> +
> +	/*
> +	 * Map the lane arrangement, which is fixed for the IPU3 (meaning we
> +	 * only need one, rather than one per sensor). We include it as a
> +	 * member of the struct cio2_bridge rather than a global variable so
> +	 * that it survives if the module is unloaded along with the rest of
> +	 * the struct.
> +	 */
> +	for (i = 0; i < CIO2_MAX_LANES; i++)
> +		bridge->data_lanes[i] = i + 1;
> +
> +	ret = cio2_bridge_connect_sensors(bridge, cio2);
> +	if (ret || bridge->n_sensors == 0)
> +		goto err_unregister_cio2;
> +
> +	dev_info(dev, "Connected %d cameras\n", bridge->n_sensors);
> +
> +	fwnode = software_node_fwnode(&bridge->cio2_hid_node);
> +	if (!fwnode) {
> +		dev_err(dev, "Error getting fwnode from cio2 software_node\n");
> +		ret = -ENODEV;
> +		goto err_unregister_sensors;
> +	}
> +
> +	set_secondary_fwnode(dev, fwnode);
> +
> +	return 0;
> +
> +err_unregister_sensors:
> +	cio2_bridge_unregister_sensors(bridge);
> +err_unregister_cio2:
> +	software_node_unregister(&bridge->cio2_hid_node);
> +err_free_bridge:
> +	kfree(bridge);
> +
> +	return ret;
> +}
> diff --git a/drivers/media/pci/intel/ipu3/cio2-bridge.h b/drivers/media/pci/intel/ipu3/cio2-bridge.h
> new file mode 100644
> index 000000000000..dd0ffcafa489
> --- /dev/null
> +++ b/drivers/media/pci/intel/ipu3/cio2-bridge.h
> @@ -0,0 +1,125 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/* Author: Dan Scally <djrscally@gmail.com> */
> +#ifndef __CIO2_BRIDGE_H
> +#define __CIO2_BRIDGE_H
> +
> +#include <linux/property.h>
> +#include <linux/types.h>
> +
> +#include "ipu3-cio2.h"
> +
> +#define CIO2_HID				"INT343E"
> +#define CIO2_MAX_LANES				4
> +#define MAX_NUM_LINK_FREQS			3
> +
> +#define CIO2_SENSOR_CONFIG(_HID, _NR, ...)	\
> +	(const struct cio2_sensor_config) {	\
> +		.hid = _HID,			\
> +		.nr_link_freqs = _NR,		\
> +		.link_freqs = { __VA_ARGS__ }	\
> +	}
> +
> +#define NODE_SENSOR(_HID, _PROPS)		\
> +	(const struct software_node) {		\
> +		.name = _HID,			\
> +		.properties = _PROPS,		\
> +	}
> +
> +#define NODE_PORT(_PORT, _SENSOR_NODE)		\
> +	(const struct software_node) {		\
> +		.name = _PORT,			\
> +		.parent = _SENSOR_NODE,		\
> +	}
> +
> +#define NODE_ENDPOINT(_EP, _PORT, _PROPS)	\
> +	(const struct software_node) {		\
> +		.name = _EP,			\
> +		.parent = _PORT,		\
> +		.properties = _PROPS,		\
> +	}
> +
> +enum cio2_sensor_swnodes {
> +	SWNODE_SENSOR_HID,
> +	SWNODE_SENSOR_PORT,
> +	SWNODE_SENSOR_ENDPOINT,
> +	SWNODE_CIO2_PORT,
> +	SWNODE_CIO2_ENDPOINT,
> +	SWNODE_COUNT
> +};
> +
> +/* Data representation as it is in ACPI SSDB buffer */
> +struct cio2_sensor_ssdb {
> +	u8 version;
> +	u8 sku;
> +	u8 guid_csi2[16];
> +	u8 devfunction;
> +	u8 bus;
> +	u32 dphylinkenfuses;
> +	u32 clockdiv;
> +	u8 link;
> +	u8 lanes;
> +	u32 csiparams[10];
> +	u32 maxlanespeed;
> +	u8 sensorcalibfileidx;
> +	u8 sensorcalibfileidxInMBZ[3];
> +	u8 romtype;
> +	u8 vcmtype;
> +	u8 platforminfo;
> +	u8 platformsubinfo;
> +	u8 flash;
> +	u8 privacyled;
> +	u8 degree;
> +	u8 mipilinkdefined;
> +	u32 mclkspeed;
> +	u8 controllogicid;
> +	u8 reserved1[3];
> +	u8 mclkport;
> +	u8 reserved2[13];
> +} __packed;
> +
> +struct cio2_property_names {
> +	char clock_frequency[16];
> +	char rotation[9];
> +	char bus_type[9];
> +	char data_lanes[11];
> +	char remote_endpoint[16];
> +	char link_frequencies[17];
> +};
> +
> +struct cio2_node_names {
> +	char port[7];
> +	char endpoint[11];
> +	char remote_port[7];
> +};
> +
> +struct cio2_sensor_config {
> +	const char *hid;
> +	const u8 nr_link_freqs;
> +	const u64 link_freqs[MAX_NUM_LINK_FREQS];
> +};
> +
> +struct cio2_sensor {
> +	char name[ACPI_ID_LEN];
> +	struct acpi_device *adev;
> +
> +	struct software_node swnodes[6];
> +	struct cio2_node_names node_names;
> +
> +	struct cio2_sensor_ssdb ssdb;
> +	struct cio2_property_names prop_names;
> +	struct property_entry ep_properties[5];
> +	struct property_entry dev_properties[3];
> +	struct property_entry cio2_properties[3];
> +	struct software_node_ref_args local_ref[1];
> +	struct software_node_ref_args remote_ref[1];
> +};
> +
> +struct cio2_bridge {
> +	char cio2_node_name[ACPI_ID_LEN];
> +	struct software_node cio2_hid_node;
> +	u32 data_lanes[4];
> +	unsigned int n_sensors;
> +	struct cio2_sensor sensors[CIO2_NUM_PORTS];
> +};
> +
> +#endif
> diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
> index 36e354ecf71e..db59b19a6236 100644
> --- a/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
> +++ b/drivers/media/pci/intel/ipu3/ipu3-cio2-main.c
> @@ -1702,11 +1702,28 @@ static void cio2_queues_exit(struct cio2_device *cio2)
>  		cio2_queue_exit(cio2, &cio2->queue[i]);
>  }
>  
> +static int cio2_check_fwnode_graph(struct fwnode_handle *fwnode)
> +{
> +	struct fwnode_handle *endpoint;
> +
> +	if (IS_ERR_OR_NULL(fwnode))
> +		return -EINVAL;
> +
> +	endpoint = fwnode_graph_get_next_endpoint(fwnode, NULL);
> +	if (endpoint) {
> +		fwnode_handle_put(endpoint);
> +		return 0;
> +	}
> +
> +	return cio2_check_fwnode_graph(fwnode->secondary);
> +}
> +
>  /**************** PCI interface ****************/
>  
>  static int cio2_pci_probe(struct pci_dev *pci_dev,
>  			  const struct pci_device_id *id)
>  {
> +	struct fwnode_handle *fwnode = dev_fwnode(&pci_dev->dev);
>  	struct cio2_device *cio2;
>  	int r;
>  
> @@ -1715,6 +1732,23 @@ static int cio2_pci_probe(struct pci_dev *pci_dev,
>  		return -ENOMEM;
>  	cio2->pci_dev = pci_dev;
>  
> +	/*
> +	 * On some platforms no connections to sensors are defined in firmware,
> +	 * if the device has no endpoints then we can try to build those as
> +	 * software_nodes parsed from SSDB.
> +	 */
> +	r = cio2_check_fwnode_graph(fwnode);
> +	if (r) {
> +		if (fwnode && !IS_ERR_OR_NULL(fwnode->secondary)) {
> +			dev_err(&pci_dev->dev, "fwnode graph has no endpoints connected\n");
> +			return -EINVAL;
> +		}
> +
> +		r = cio2_bridge_init(pci_dev);
> +		if (r)
> +			return r;
> +	}
> +
>  	r = pcim_enable_device(pci_dev);
>  	if (r) {
>  		dev_err(&pci_dev->dev, "failed to enable device (%d)\n", r);
> diff --git a/drivers/media/pci/intel/ipu3/ipu3-cio2.h b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
> index 62187ab5ae43..dc3e343a37fb 100644
> --- a/drivers/media/pci/intel/ipu3/ipu3-cio2.h
> +++ b/drivers/media/pci/intel/ipu3/ipu3-cio2.h
> @@ -455,4 +455,10 @@ static inline struct cio2_queue *vb2q_to_cio2_queue(struct vb2_queue *vq)
>  	return container_of(vq, struct cio2_queue, vbq);
>  }
>  
> +#if IS_ENABLED(CONFIG_CIO2_BRIDGE)
> +int cio2_bridge_init(struct pci_dev *cio2);
> +#else
> +int cio2_bridge_init(struct pci_dev *cio2) { return 0; }
> +#endif
> +
>  #endif
>