/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * V4L2 asynchronous subdevice registration API
 *
 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
 */

#ifndef V4L2_ASYNC_H
#define V4L2_ASYNC_H

#include <linux/list.h>
#include <linux/mutex.h>

struct dentry;
struct device;
struct device_node;
struct v4l2_device;
struct v4l2_subdev;
struct v4l2_async_notifier;

/**
 * enum v4l2_async_match_type - type of asynchronous subdevice logic to be used
 *      in order to identify a match
 *
 * @V4L2_ASYNC_MATCH_I2C: Match will check for I2C adapter ID and address
 * @V4L2_ASYNC_MATCH_FWNODE: Match will use firmware node
 *
 * This enum is used by the asynchronous sub-device logic to define the
 * algorithm that will be used to match an asynchronous device.
 */
enum v4l2_async_match_type {
        V4L2_ASYNC_MATCH_I2C,
        V4L2_ASYNC_MATCH_FWNODE,
};

/**
 * struct v4l2_async_subdev - sub-device descriptor, as known to a bridge
 *
 * @match_type: type of match that will be used
 * @match:      union of per-bus type matching data sets
 * @match.fwnode:
 *              pointer to &struct fwnode_handle to be matched.
 *              Used if @match_type is %V4L2_ASYNC_MATCH_FWNODE.
 * @match.i2c:  embedded struct with I2C parameters to be matched.
 *              Both @match.i2c.adapter_id and @match.i2c.address
 *              should be matched.
 *              Used if @match_type is %V4L2_ASYNC_MATCH_I2C.
 * @match.i2c.adapter_id:
 *              I2C adapter ID to be matched.
 *              Used if @match_type is %V4L2_ASYNC_MATCH_I2C.
 * @match.i2c.address:
 *              I2C address to be matched.
 *              Used if @match_type is %V4L2_ASYNC_MATCH_I2C.
 * @asd_list:   used to add struct v4l2_async_subdev objects to the
 *              master notifier @asd_list
 * @list:       used to link struct v4l2_async_subdev objects, waiting to be
 *              probed, to a notifier->waiting list
 *
 * When this struct is used as a member in a driver specific struct,
 * the driver specific struct shall contain the &struct
 * v4l2_async_subdev as its first member.
 */
struct v4l2_async_subdev {
        enum v4l2_async_match_type match_type;
        union {
                struct fwnode_handle *fwnode;
                struct {
                        int adapter_id;
                        unsigned short address;
                } i2c;
        } match;

        /* v4l2-async core private: not to be used by drivers */
        struct list_head list;
        struct list_head asd_list;
};

/**
 * struct v4l2_async_notifier_operations - Asynchronous V4L2 notifier operations
 * @bound:      a subdevice driver has successfully probed one of the subdevices
 * @complete:   All subdevices have been probed successfully. The complete
 *              callback is only executed for the root notifier.
 * @unbind:     a subdevice is leaving
 */
struct v4l2_async_notifier_operations {
        int (*bound)(struct v4l2_async_notifier *notifier,
                     struct v4l2_subdev *subdev,
                     struct v4l2_async_subdev *asd);
        int (*complete)(struct v4l2_async_notifier *notifier);
        void (*unbind)(struct v4l2_async_notifier *notifier,
                       struct v4l2_subdev *subdev,
                       struct v4l2_async_subdev *asd);
};

/**
 * struct v4l2_async_notifier - v4l2_device notifier data
 *
 * @ops:        notifier operations
 * @v4l2_dev:   v4l2_device of the root notifier, NULL otherwise
 * @sd:         sub-device that registered the notifier, NULL otherwise
 * @parent:     parent notifier
 * @asd_list:   master list of struct v4l2_async_subdev
 * @waiting:    list of struct v4l2_async_subdev, waiting for their drivers
 * @done:       list of struct v4l2_subdev, already probed
 * @list:       member in a global list of notifiers
 */
struct v4l2_async_notifier {
        const struct v4l2_async_notifier_operations *ops;
        struct v4l2_device *v4l2_dev;
        struct v4l2_subdev *sd;
        struct v4l2_async_notifier *parent;
        struct list_head asd_list;
        struct list_head waiting;
        struct list_head done;
        struct list_head list;
};

/**
 * v4l2_async_debug_init - Initialize debugging tools.
 *
 * @debugfs_dir: pointer to the parent debugfs &struct dentry
 */
void v4l2_async_debug_init(struct dentry *debugfs_dir);

/**
 * v4l2_async_nf_init - Initialize a notifier.
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 *
 * This function initializes the notifier @asd_list. It must be called
 * before adding a subdevice to a notifier, using one of:
 * v4l2_async_nf_add_fwnode_remote(),
 * v4l2_async_nf_add_fwnode(),
 * v4l2_async_nf_add_i2c(),
 * __v4l2_async_nf_add_subdev() or
 * v4l2_async_nf_parse_fwnode_endpoints().
 */
void v4l2_async_nf_init(struct v4l2_async_notifier *notifier);

/**
 * __v4l2_async_nf_add_subdev - Add an async subdev to the
 *                              notifier's master asd list.
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 * @asd: pointer to &struct v4l2_async_subdev
 *
 * \warning: Drivers should avoid using this function and instead use one of:
 * v4l2_async_nf_add_fwnode(),
 * v4l2_async_nf_add_fwnode_remote() or
 * v4l2_async_nf_add_i2c().
 *
 * Call this function before registering a notifier to link the provided @asd to
 * the notifiers master @asd_list. The @asd must be allocated with k*alloc() as
 * it will be freed by the framework when the notifier is destroyed.
 */
int __v4l2_async_nf_add_subdev(struct v4l2_async_notifier *notifier,
                               struct v4l2_async_subdev *asd);

struct v4l2_async_subdev *
__v4l2_async_nf_add_fwnode(struct v4l2_async_notifier *notifier,
                           struct fwnode_handle *fwnode,
                           unsigned int asd_struct_size);
/**
 * v4l2_async_nf_add_fwnode - Allocate and add a fwnode async
 *                              subdev to the notifier's master asd_list.
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 * @fwnode: fwnode handle of the sub-device to be matched, pointer to
 *          &struct fwnode_handle
 * @type: Type of the driver's async sub-device struct. The &struct
 *        v4l2_async_subdev shall be the first member of the driver's async
 *        sub-device struct, i.e. both begin at the same memory address.
 *
 * Allocate a fwnode-matched asd of size asd_struct_size, and add it to the
 * notifiers @asd_list. The function also gets a reference of the fwnode which
 * is released later at notifier cleanup time.
 */
#define v4l2_async_nf_add_fwnode(notifier, fwnode, type)                \
        ((type *)__v4l2_async_nf_add_fwnode(notifier, fwnode, sizeof(type)))

struct v4l2_async_subdev *
__v4l2_async_nf_add_fwnode_remote(struct v4l2_async_notifier *notif,
                                  struct fwnode_handle *endpoint,
                                  unsigned int asd_struct_size);
/**
 * v4l2_async_nf_add_fwnode_remote - Allocate and add a fwnode
 *                                                remote async subdev to the
 *                                                notifier's master asd_list.
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 * @ep: local endpoint pointing to the remote sub-device to be matched,
 *      pointer to &struct fwnode_handle
 * @type: Type of the driver's async sub-device struct. The &struct
 *        v4l2_async_subdev shall be the first member of the driver's async
 *        sub-device struct, i.e. both begin at the same memory address.
 *
 * Gets the remote endpoint of a given local endpoint, set it up for fwnode
 * matching and adds the async sub-device to the notifier's @asd_list. The
 * function also gets a reference of the fwnode which is released later at
 * notifier cleanup time.
 *
 * This is just like v4l2_async_nf_add_fwnode(), but with the
 * exception that the fwnode refers to a local endpoint, not the remote one.
 */
#define v4l2_async_nf_add_fwnode_remote(notifier, ep, type) \
        ((type *)__v4l2_async_nf_add_fwnode_remote(notifier, ep, sizeof(type)))

struct v4l2_async_subdev *
__v4l2_async_nf_add_i2c(struct v4l2_async_notifier *notifier,
                        int adapter_id, unsigned short address,
                        unsigned int asd_struct_size);
/**
 * v4l2_async_nf_add_i2c - Allocate and add an i2c async
 *                              subdev to the notifier's master asd_list.
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 * @adapter: I2C adapter ID to be matched
 * @address: I2C address of sub-device to be matched
 * @type: Type of the driver's async sub-device struct. The &struct
 *        v4l2_async_subdev shall be the first member of the driver's async
 *        sub-device struct, i.e. both begin at the same memory address.
 *
 * Same as v4l2_async_nf_add_fwnode() but for I2C matched
 * sub-devices.
 */
#define v4l2_async_nf_add_i2c(notifier, adapter, address, type) \
        ((type *)__v4l2_async_nf_add_i2c(notifier, adapter, address, \
                                         sizeof(type)))

/**
 * v4l2_async_nf_register - registers a subdevice asynchronous notifier
 *
 * @v4l2_dev: pointer to &struct v4l2_device
 * @notifier: pointer to &struct v4l2_async_notifier
 */
int v4l2_async_nf_register(struct v4l2_device *v4l2_dev,
                           struct v4l2_async_notifier *notifier);

/**
 * v4l2_async_subdev_nf_register - registers a subdevice asynchronous
 *                                       notifier for a sub-device
 *
 * @sd: pointer to &struct v4l2_subdev
 * @notifier: pointer to &struct v4l2_async_notifier
 */
int v4l2_async_subdev_nf_register(struct v4l2_subdev *sd,
                                  struct v4l2_async_notifier *notifier);

/**
 * v4l2_async_nf_unregister - unregisters a subdevice
 *      asynchronous notifier
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 */
void v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier);

/**
 * v4l2_async_nf_cleanup - clean up notifier resources
 * @notifier: the notifier the resources of which are to be cleaned up
 *
 * Release memory resources related to a notifier, including the async
 * sub-devices allocated for the purposes of the notifier but not the notifier
 * itself. The user is responsible for calling this function to clean up the
 * notifier after calling
 * v4l2_async_nf_add_fwnode_remote(),
 * v4l2_async_nf_add_fwnode(),
 * v4l2_async_nf_add_i2c(),
 * __v4l2_async_nf_add_subdev() or
 * v4l2_async_nf_parse_fwnode_endpoints().
 *
 * There is no harm from calling v4l2_async_nf_cleanup() in other
 * cases as long as its memory has been zeroed after it has been
 * allocated.
 */
void v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier);

/**
 * v4l2_async_register_subdev - registers a sub-device to the asynchronous
 *      subdevice framework
 *
 * @sd: pointer to &struct v4l2_subdev
 */
int v4l2_async_register_subdev(struct v4l2_subdev *sd);

/**
 * v4l2_async_register_subdev_sensor - registers a sensor sub-device to the
 *                                     asynchronous sub-device framework and
 *                                     parse set up common sensor related
 *                                     devices
 *
 * @sd: pointer to struct &v4l2_subdev
 *
 * This function is just like v4l2_async_register_subdev() with the exception
 * that calling it will also parse firmware interfaces for remote references
 * using v4l2_async_nf_parse_fwnode_sensor() and registers the
 * async sub-devices. The sub-device is similarly unregistered by calling
 * v4l2_async_unregister_subdev().
 *
 * While registered, the subdev module is marked as in-use.
 *
 * An error is returned if the module is no longer loaded on any attempts
 * to register it.
 */
int __must_check
v4l2_async_register_subdev_sensor(struct v4l2_subdev *sd);

/**
 * v4l2_async_unregister_subdev - unregisters a sub-device to the asynchronous
 *      subdevice framework
 *
 * @sd: pointer to &struct v4l2_subdev
 */
void v4l2_async_unregister_subdev(struct v4l2_subdev *sd);
#endif