1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * V4L2 asynchronous subdevice registration API
4 *
5 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
6 */
7
8#ifndef V4L2_ASYNC_H
9#define V4L2_ASYNC_H
10
11#include <linux/list.h>
12#include <linux/mutex.h>
13
14struct device;
15struct device_node;
16struct v4l2_device;
17struct v4l2_subdev;
18struct v4l2_async_notifier;
19
20/**
21 * enum v4l2_async_match_type - type of asynchronous subdevice logic to be used
22 *    in order to identify a match
23 *
24 * @V4L2_ASYNC_MATCH_CUSTOM: Match will use the logic provided by &struct
25 *    v4l2_async_subdev.match ops
26 * @V4L2_ASYNC_MATCH_DEVNAME: Match will use the device name
27 * @V4L2_ASYNC_MATCH_I2C: Match will check for I2C adapter ID and address
28 * @V4L2_ASYNC_MATCH_FWNODE: Match will use firmware node
29 *
30 * This enum is used by the asyncrhronous sub-device logic to define the
31 * algorithm that will be used to match an asynchronous device.
32 */
33enum v4l2_async_match_type {
34    V4L2_ASYNC_MATCH_CUSTOM,
35    V4L2_ASYNC_MATCH_DEVNAME,
36    V4L2_ASYNC_MATCH_I2C,
37    V4L2_ASYNC_MATCH_FWNODE,
38};
39
40/**
41 * struct v4l2_async_subdev - sub-device descriptor, as known to a bridge
42 *
43 * @match_type:    type of match that will be used
44 * @match:    union of per-bus type matching data sets
45 * @match.fwnode:
46 *        pointer to &struct fwnode_handle to be matched.
47 *        Used if @match_type is %V4L2_ASYNC_MATCH_FWNODE.
48 * @match.device_name:
49 *        string containing the device name to be matched.
50 *        Used if @match_type is %V4L2_ASYNC_MATCH_DEVNAME.
51 * @match.i2c:    embedded struct with I2C parameters to be matched.
52 *        Both @match.i2c.adapter_id and @match.i2c.address
53 *        should be matched.
54 *        Used if @match_type is %V4L2_ASYNC_MATCH_I2C.
55 * @match.i2c.adapter_id:
56 *        I2C adapter ID to be matched.
57 *        Used if @match_type is %V4L2_ASYNC_MATCH_I2C.
58 * @match.i2c.address:
59 *        I2C address to be matched.
60 *        Used if @match_type is %V4L2_ASYNC_MATCH_I2C.
61 * @match.custom:
62 *        Driver-specific match criteria.
63 *        Used if @match_type is %V4L2_ASYNC_MATCH_CUSTOM.
64 * @match.custom.match:
65 *        Driver-specific match function to be used if
66 *        %V4L2_ASYNC_MATCH_CUSTOM.
67 * @match.custom.priv:
68 *        Driver-specific private struct with match parameters
69 *        to be used if %V4L2_ASYNC_MATCH_CUSTOM.
70 * @asd_list:    used to add struct v4l2_async_subdev objects to the
71 *        master notifier @asd_list
72 * @list:    used to link struct v4l2_async_subdev objects, waiting to be
73 *        probed, to a notifier->waiting list
74 *
75 * When this struct is used as a member in a driver specific struct,
76 * the driver specific struct shall contain the &struct
77 * v4l2_async_subdev as its first member.
78 */
79struct v4l2_async_subdev {
80    enum v4l2_async_match_type match_type;
81    union {
82        struct fwnode_handle *fwnode;
83        const char *device_name;
84        struct {
85            int adapter_id;
86            unsigned short address;
87        } i2c;
88        struct {
89            bool (*match)(struct device *dev, struct v4l2_async_subdev *sd);
90            void *priv;
91        } custom;
92    } match;
93
94    /* v4l2-async core private: not to be used by drivers */
95    struct list_head list;
96    struct list_head asd_list;
97};
98
99/**
100 * struct v4l2_async_notifier_operations - Asynchronous V4L2 notifier operations
101 * @bound:    a subdevice driver has successfully probed one of the subdevices
102 * @complete:    All subdevices have been probed successfully. The complete
103 *        callback is only executed for the root notifier.
104 * @unbind:    a subdevice is leaving
105 */
106struct v4l2_async_notifier_operations {
107    int (*bound)(struct v4l2_async_notifier *notifier, struct v4l2_subdev *subdev, struct v4l2_async_subdev *asd);
108    int (*complete)(struct v4l2_async_notifier *notifier);
109    void (*unbind)(struct v4l2_async_notifier *notifier, struct v4l2_subdev *subdev, struct v4l2_async_subdev *asd);
110};
111
112/**
113 * struct v4l2_async_notifier - v4l2_device notifier data
114 *
115 * @ops:    notifier operations
116 * @v4l2_dev:    v4l2_device of the root notifier, NULL otherwise
117 * @sd:        sub-device that registered the notifier, NULL otherwise
118 * @parent:    parent notifier
119 * @asd_list:    master list of struct v4l2_async_subdev
120 * @waiting:    list of struct v4l2_async_subdev, waiting for their drivers
121 * @done:    list of struct v4l2_subdev, already probed
122 * @list:    member in a global list of notifiers
123 */
124struct v4l2_async_notifier {
125    const struct v4l2_async_notifier_operations *ops;
126    struct v4l2_device *v4l2_dev;
127    struct v4l2_subdev *sd;
128    struct v4l2_async_notifier *parent;
129    struct list_head asd_list;
130    struct list_head waiting;
131    struct list_head done;
132    struct list_head list;
133};
134
135/**
136 * v4l2_async_notifier_init - Initialize a notifier.
137 *
138 * @notifier: pointer to &struct v4l2_async_notifier
139 *
140 * This function initializes the notifier @asd_list. It must be called
141 * before the first call to @v4l2_async_notifier_add_subdev.
142 */
143void v4l2_async_notifier_init(struct v4l2_async_notifier *notifier);
144
145/**
146 * v4l2_async_notifier_add_subdev - Add an async subdev to the
147 *                notifier's master asd list.
148 *
149 * @notifier: pointer to &struct v4l2_async_notifier
150 * @asd: pointer to &struct v4l2_async_subdev
151 *
152 * Call this function before registering a notifier to link the provided @asd to
153 * the notifiers master @asd_list. The @asd must be allocated with k*alloc() as
154 * it will be freed by the framework when the notifier is destroyed.
155 */
156int v4l2_async_notifier_add_subdev(struct v4l2_async_notifier *notifier, struct v4l2_async_subdev *asd);
157
158/**
159 * v4l2_async_notifier_add_fwnode_subdev - Allocate and add a fwnode async
160 *                subdev to the notifier's master asd_list.
161 *
162 * @notifier: pointer to &struct v4l2_async_notifier
163 * @fwnode: fwnode handle of the sub-device to be matched
164 * @asd_struct_size: size of the driver's async sub-device struct, including
165 *             sizeof(struct v4l2_async_subdev). The &struct
166 *             v4l2_async_subdev shall be the first member of
167 *             the driver's async sub-device struct, i.e. both
168 *             begin at the same memory address.
169 *
170 * Allocate a fwnode-matched asd of size asd_struct_size, and add it to the
171 * notifiers @asd_list. The function also gets a reference of the fwnode which
172 * is released later at notifier cleanup time.
173 */
174struct v4l2_async_subdev *v4l2_async_notifier_add_fwnode_subdev(struct v4l2_async_notifier *notifier,
175                                                                struct fwnode_handle *fwnode,
176                                                                unsigned int asd_struct_size);
177
178/**
179 * v4l2_async_notifier_add_fwnode_remote_subdev - Allocate and add a fwnode
180 *                          remote async subdev to the
181 *                          notifier's master asd_list.
182 *
183 * @notif: pointer to &struct v4l2_async_notifier
184 * @endpoint: local endpoint pointing to the remote sub-device to be matched
185 * @asd_struct_size: size of the driver's async sub-device struct, including
186 *             sizeof(struct v4l2_async_subdev). The &struct
187 *             v4l2_async_subdev shall be the first member of
188 *             the driver's async sub-device struct, i.e. both
189 *             begin at the same memory address.
190 *
191 * Gets the remote endpoint of a given local endpoint, set it up for fwnode
192 * matching and adds the async sub-device to the notifier's @asd_list. The
193 * function also gets a reference of the fwnode which is released later at
194 * notifier cleanup time.
195 *
196 * This is just like @v4l2_async_notifier_add_fwnode_subdev, but with the
197 * exception that the fwnode refers to a local endpoint, not the remote one.
198 */
199struct v4l2_async_subdev *v4l2_async_notifier_add_fwnode_remote_subdev(struct v4l2_async_notifier *notif,
200                                                                       struct fwnode_handle *endpoint,
201                                                                       unsigned int asd_struct_size);
202
203/**
204 * v4l2_async_notifier_add_i2c_subdev - Allocate and add an i2c async
205 *                subdev to the notifier's master asd_list.
206 *
207 * @notifier: pointer to &struct v4l2_async_notifier
208 * @adapter_id: I2C adapter ID to be matched
209 * @address: I2C address of sub-device to be matched
210 * @asd_struct_size: size of the driver's async sub-device struct, including
211 *             sizeof(struct v4l2_async_subdev). The &struct
212 *             v4l2_async_subdev shall be the first member of
213 *             the driver's async sub-device struct, i.e. both
214 *             begin at the same memory address.
215 *
216 * Same as above but for I2C matched sub-devices.
217 */
218struct v4l2_async_subdev *v4l2_async_notifier_add_i2c_subdev(struct v4l2_async_notifier *notifier, int adapter_id,
219                                                             unsigned short address, unsigned int asd_struct_size);
220
221/**
222 * v4l2_async_notifier_add_devname_subdev - Allocate and add a device-name
223 *                async subdev to the notifier's master asd_list.
224 *
225 * @notifier: pointer to &struct v4l2_async_notifier
226 * @device_name: device name string to be matched
227 * @asd_struct_size: size of the driver's async sub-device struct, including
228 *             sizeof(struct v4l2_async_subdev). The &struct
229 *             v4l2_async_subdev shall be the first member of
230 *             the driver's async sub-device struct, i.e. both
231 *             begin at the same memory address.
232 *
233 * Same as above but for device-name matched sub-devices.
234 */
235struct v4l2_async_subdev *v4l2_async_notifier_add_devname_subdev(struct v4l2_async_notifier *notifier,
236                                                                 const char *device_name, unsigned int asd_struct_size);
237
238/**
239 * v4l2_async_notifier_register - registers a subdevice asynchronous notifier
240 *
241 * @v4l2_dev: pointer to &struct v4l2_device
242 * @notifier: pointer to &struct v4l2_async_notifier
243 */
244int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev, struct v4l2_async_notifier *notifier);
245
246/**
247 * v4l2_async_subdev_notifier_register - registers a subdevice asynchronous
248 *                     notifier for a sub-device
249 *
250 * @sd: pointer to &struct v4l2_subdev
251 * @notifier: pointer to &struct v4l2_async_notifier
252 */
253int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd, struct v4l2_async_notifier *notifier);
254
255/**
256 * v4l2_async_notifier_clr_unready_dev - remove unready subdevice
257 *
258 * @notifier: pointer to &struct v4l2_async_notifier
259 */
260#if IS_ENABLED(CONFIG_NO_GKI)
261int v4l2_async_notifier_clr_unready_dev(struct v4l2_async_notifier *notifier);
262#else
263static inline int v4l2_async_notifier_clr_unready_dev(struct v4l2_async_notifier *notifier)
264{
265    return 0;
266}
267#endif
268
269/**
270 * v4l2_async_notifier_unregister - unregisters a subdevice
271 *    asynchronous notifier
272 *
273 * @notifier: pointer to &struct v4l2_async_notifier
274 */
275void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier);
276
277/**
278 * v4l2_async_notifier_cleanup - clean up notifier resources
279 * @notifier: the notifier the resources of which are to be cleaned up
280 *
281 * Release memory resources related to a notifier, including the async
282 * sub-devices allocated for the purposes of the notifier but not the notifier
283 * itself. The user is responsible for calling this function to clean up the
284 * notifier after calling
285 * @v4l2_async_notifier_add_subdev,
286 * @v4l2_async_notifier_parse_fwnode_endpoints or
287 * @v4l2_fwnode_reference_parse_sensor_common.
288 *
289 * There is no harm from calling v4l2_async_notifier_cleanup in other
290 * cases as long as its memory has been zeroed after it has been
291 * allocated.
292 */
293void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier);
294
295/**
296 * v4l2_async_register_subdev - registers a sub-device to the asynchronous
297 *    subdevice framework
298 *
299 * @sd: pointer to &struct v4l2_subdev
300 */
301int v4l2_async_register_subdev(struct v4l2_subdev *sd);
302
303/**
304 * v4l2_async_register_subdev_sensor_common - registers a sensor sub-device to
305 *                          the asynchronous sub-device
306 *                          framework and parse set up common
307 *                          sensor related devices
308 *
309 * @sd: pointer to struct &v4l2_subdev
310 *
311 * This function is just like v4l2_async_register_subdev() with the exception
312 * that calling it will also parse firmware interfaces for remote references
313 * using v4l2_async_notifier_parse_fwnode_sensor_common() and registers the
314 * async sub-devices. The sub-device is similarly unregistered by calling
315 * v4l2_async_unregister_subdev().
316 *
317 * While registered, the subdev module is marked as in-use.
318 *
319 * An error is returned if the module is no longer loaded on any attempts
320 * to register it.
321 */
322int __must_check v4l2_async_register_subdev_sensor_common(struct v4l2_subdev *sd);
323
324/**
325 * v4l2_async_unregister_subdev - unregisters a sub-device to the asynchronous
326 *    subdevice framework
327 *
328 * @sd: pointer to &struct v4l2_subdev
329 */
330void v4l2_async_unregister_subdev(struct v4l2_subdev *sd);
331#endif
332