xref: /openbmc/linux/include/media/v4l2-async.h (revision ee8a99bd)
1 /*
2  * V4L2 asynchronous subdevice registration API
3  *
4  * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 
11 #ifndef V4L2_ASYNC_H
12 #define V4L2_ASYNC_H
13 
14 #include <linux/list.h>
15 #include <linux/mutex.h>
16 
17 struct device;
18 struct v4l2_device;
19 struct v4l2_subdev;
20 struct v4l2_async_notifier;
21 
22 /* A random max subdevice number, used to allocate an array on stack */
23 #define V4L2_MAX_SUBDEVS 128U
24 
25 enum v4l2_async_bus_type {
26 	V4L2_ASYNC_BUS_CUSTOM,
27 	V4L2_ASYNC_BUS_PLATFORM,
28 	V4L2_ASYNC_BUS_I2C,
29 };
30 
31 /**
32  * struct v4l2_async_subdev - sub-device descriptor, as known to a bridge
33  * @bus_type:	subdevice bus type to select the appropriate matching method
34  * @match:	union of per-bus type matching data sets
35  * @list:	used to link struct v4l2_async_subdev objects, waiting to be
36  *		probed, to a notifier->waiting list
37  */
38 struct v4l2_async_subdev {
39 	enum v4l2_async_bus_type bus_type;
40 	union {
41 		struct {
42 			const char *name;
43 		} platform;
44 		struct {
45 			int adapter_id;
46 			unsigned short address;
47 		} i2c;
48 		struct {
49 			bool (*match)(struct device *,
50 				      struct v4l2_async_subdev *);
51 			void *priv;
52 		} custom;
53 	} match;
54 
55 	/* v4l2-async core private: not to be used by drivers */
56 	struct list_head list;
57 };
58 
59 /**
60  * v4l2_async_subdev_list - provided by subdevices
61  * @list:	links struct v4l2_async_subdev_list objects to a global list
62  *		before probing, and onto notifier->done after probing
63  * @asd:	pointer to respective struct v4l2_async_subdev
64  * @notifier:	pointer to managing notifier
65  */
66 struct v4l2_async_subdev_list {
67 	struct list_head list;
68 	struct v4l2_async_subdev *asd;
69 	struct v4l2_async_notifier *notifier;
70 };
71 
72 /**
73  * v4l2_async_notifier - v4l2_device notifier data
74  * @num_subdevs:number of subdevices
75  * @subdev:	array of pointers to subdevice descriptors
76  * @v4l2_dev:	pointer to struct v4l2_device
77  * @waiting:	list of struct v4l2_async_subdev, waiting for their drivers
78  * @done:	list of struct v4l2_async_subdev_list, already probed
79  * @list:	member in a global list of notifiers
80  * @bound:	a subdevice driver has successfully probed one of subdevices
81  * @complete:	all subdevices have been probed successfully
82  * @unbind:	a subdevice is leaving
83  */
84 struct v4l2_async_notifier {
85 	unsigned int num_subdevs;
86 	struct v4l2_async_subdev **subdev;
87 	struct v4l2_device *v4l2_dev;
88 	struct list_head waiting;
89 	struct list_head done;
90 	struct list_head list;
91 	int (*bound)(struct v4l2_async_notifier *notifier,
92 		     struct v4l2_subdev *subdev,
93 		     struct v4l2_async_subdev *asd);
94 	int (*complete)(struct v4l2_async_notifier *notifier);
95 	void (*unbind)(struct v4l2_async_notifier *notifier,
96 		       struct v4l2_subdev *subdev,
97 		       struct v4l2_async_subdev *asd);
98 };
99 
100 int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
101 				 struct v4l2_async_notifier *notifier);
102 void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
103 int v4l2_async_register_subdev(struct v4l2_subdev *sd);
104 void v4l2_async_unregister_subdev(struct v4l2_subdev *sd);
105 #endif
106