include/media/v4l2-async.h

/* 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 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_CUSTOM: Match will use the logic provided by &struct
 *    v4l2_async_subdev.match ops
 * @V4L2_ASYNC_MATCH_DEVNAME: Match will use the device name
 * @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 asyncrhronous sub-device logic to define the
 * algorithm that will be used to match an asynchronous device.
 */
enum v4l2_async_match_type {
    V4L2_ASYNC_MATCH_CUSTOM,
    V4L2_ASYNC_MATCH_DEVNAME,
    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.device_name:
 *        string containing the device name to be matched.
 *        Used if @match_type is %V4L2_ASYNC_MATCH_DEVNAME.
 * @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.
 * @match.custom:
 *        Driver-specific match criteria.
 *        Used if @match_type is %V4L2_ASYNC_MATCH_CUSTOM.
 * @match.custom.match:
 *        Driver-specific match function to be used if
 *        %V4L2_ASYNC_MATCH_CUSTOM.
 * @match.custom.priv:
 *        Driver-specific private struct with match parameters
 *        to be used if %V4L2_ASYNC_MATCH_CUSTOM.
 * @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;
        const char *device_name;
        struct {
            int adapter_id;
            unsigned short address;
        } i2c;
        struct {
            bool (*match)(struct device *dev, struct v4l2_async_subdev *sd);
            void *priv;
        } custom;
    } 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_notifier_init - Initialize a notifier.
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 *
 * This function initializes the notifier @asd_list. It must be called
 * before the first call to @v4l2_async_notifier_add_subdev.
 */
void v4l2_async_notifier_init(struct v4l2_async_notifier *notifier);

/**
 * v4l2_async_notifier_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
 *
 * 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_notifier_add_subdev(struct v4l2_async_notifier *notifier, struct v4l2_async_subdev *asd);

/**
 * v4l2_async_notifier_add_fwnode_subdev - 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
 * @asd_struct_size: size of the driver's async sub-device struct, including
 *             sizeof(struct v4l2_async_subdev). 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.
 */
struct v4l2_async_subdev *v4l2_async_notifier_add_fwnode_subdev(struct v4l2_async_notifier *notifier,
                                                                struct fwnode_handle *fwnode,
                                                                unsigned int asd_struct_size);

/**
 * v4l2_async_notifier_add_fwnode_remote_subdev - Allocate and add a fwnode
 *                          remote async subdev to the
 *                          notifier's master asd_list.
 *
 * @notif: pointer to &struct v4l2_async_notifier
 * @endpoint: local endpoint pointing to the remote sub-device to be matched
 * @asd_struct_size: size of the driver's async sub-device struct, including
 *             sizeof(struct v4l2_async_subdev). 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_notifier_add_fwnode_subdev, but with the
 * exception that the fwnode refers to a local endpoint, not the remote one.
 */
struct v4l2_async_subdev *v4l2_async_notifier_add_fwnode_remote_subdev(struct v4l2_async_notifier *notif,
                                                                       struct fwnode_handle *endpoint,
                                                                       unsigned int asd_struct_size);

/**
 * v4l2_async_notifier_add_i2c_subdev - Allocate and add an i2c async
 *                subdev to the notifier's master asd_list.
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 * @adapter_id: I2C adapter ID to be matched
 * @address: I2C address of sub-device to be matched
 * @asd_struct_size: size of the driver's async sub-device struct, including
 *             sizeof(struct v4l2_async_subdev). 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 above but for I2C matched sub-devices.
 */
struct v4l2_async_subdev *v4l2_async_notifier_add_i2c_subdev(struct v4l2_async_notifier *notifier, int adapter_id,
                                                             unsigned short address, unsigned int asd_struct_size);

/**
 * v4l2_async_notifier_add_devname_subdev - Allocate and add a device-name
 *                async subdev to the notifier's master asd_list.
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 * @device_name: device name string to be matched
 * @asd_struct_size: size of the driver's async sub-device struct, including
 *             sizeof(struct v4l2_async_subdev). 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 above but for device-name matched sub-devices.
 */
struct v4l2_async_subdev *v4l2_async_notifier_add_devname_subdev(struct v4l2_async_notifier *notifier,
                                                                 const char *device_name, unsigned int asd_struct_size);

/**
 * v4l2_async_notifier_register - registers a subdevice asynchronous notifier
 *
 * @v4l2_dev: pointer to &struct v4l2_device
 * @notifier: pointer to &struct v4l2_async_notifier
 */
int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, struct v4l2_async_notifier *notifier);

/**
 * v4l2_async_subdev_notifier_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_notifier_register(struct v4l2_subdev *sd, struct v4l2_async_notifier *notifier);

/**
 * v4l2_async_notifier_clr_unready_dev - remove unready subdevice
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 */
#if IS_ENABLED(CONFIG_NO_GKI)
int v4l2_async_notifier_clr_unready_dev(struct v4l2_async_notifier *notifier);
#else
static inline int v4l2_async_notifier_clr_unready_dev(struct v4l2_async_notifier *notifier)
{
    return 0;
}
#endif

/**
 * v4l2_async_notifier_unregister - unregisters a subdevice
 *    asynchronous notifier
 *
 * @notifier: pointer to &struct v4l2_async_notifier
 */
void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);

/**
 * v4l2_async_notifier_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_notifier_add_subdev,
 * @v4l2_async_notifier_parse_fwnode_endpoints or
 * @v4l2_fwnode_reference_parse_sensor_common.
 *
 * There is no harm from calling v4l2_async_notifier_cleanup in other
 * cases as long as its memory has been zeroed after it has been
 * allocated.
 */
void v4l2_async_notifier_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_common - 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_notifier_parse_fwnode_sensor_common() 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_common(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