xref: /openbmc/linux/include/media/v4l2-mc.h (revision bd5a03bc)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /*
3  * v4l2-mc.h - Media Controller V4L2 types and prototypes
4  *
5  * Copyright (C) 2016 Mauro Carvalho Chehab <mchehab@kernel.org>
6  * Copyright (C) 2006-2010 Nokia Corporation
7  * Copyright (c) 2016 Intel Corporation.
8  */
9 
10 #ifndef _V4L2_MC_H
11 #define _V4L2_MC_H
12 
13 #include <media/media-device.h>
14 #include <media/v4l2-dev.h>
15 #include <media/v4l2-subdev.h>
16 #include <linux/types.h>
17 
18 /* We don't need to include pci.h or usb.h here */
19 struct pci_dev;
20 struct usb_device;
21 
22 #ifdef CONFIG_MEDIA_CONTROLLER
23 /**
24  * v4l2_mc_create_media_graph() - create Media Controller links at the graph.
25  *
26  * @mdev:	pointer to the &media_device struct.
27  *
28  * Add links between the entities commonly found on PC customer's hardware at
29  * the V4L2 side: camera sensors, audio and video PLL-IF decoders, tuners,
30  * analog TV decoder and I/O entities (video, VBI and Software Defined Radio).
31  *
32  * .. note::
33  *
34  *    Webcams are modelled on a very simple way: the sensor is
35  *    connected directly to the I/O entity. All dirty details, like
36  *    scaler and crop HW are hidden. While such mapping is enough for v4l2
37  *    interface centric PC-consumer's hardware, V4L2 subdev centric camera
38  *    hardware should not use this routine, as it will not build the right graph.
39  */
40 int v4l2_mc_create_media_graph(struct media_device *mdev);
41 
42 /**
43  * v4l_enable_media_source() -	Hold media source for exclusive use
44  *				if free
45  *
46  * @vdev:	pointer to struct video_device
47  *
48  * This interface calls enable_source handler to determine if
49  * media source is free for use. The enable_source handler is
50  * responsible for checking is the media source is free and
51  * start a pipeline between the media source and the media
52  * entity associated with the video device. This interface
53  * should be called from v4l2-core and dvb-core interfaces
54  * that change the source configuration.
55  *
56  * Return: returns zero on success or a negative error code.
57  */
58 int v4l_enable_media_source(struct video_device *vdev);
59 
60 /**
61  * v4l_disable_media_source() -	Release media source
62  *
63  * @vdev:	pointer to struct video_device
64  *
65  * This interface calls disable_source handler to release
66  * the media source. The disable_source handler stops the
67  * active media pipeline between the media source and the
68  * media entity associated with the video device.
69  *
70  * Return: returns zero on success or a negative error code.
71  */
72 void v4l_disable_media_source(struct video_device *vdev);
73 
74 /*
75  * v4l_vb2q_enable_media_tuner -  Hold media source for exclusive use
76  *				  if free.
77  * @q - pointer to struct vb2_queue
78  *
79  * Wrapper for v4l_enable_media_source(). This function should
80  * be called from v4l2-core to enable the media source with
81  * pointer to struct vb2_queue as the input argument. Some
82  * v4l2-core interfaces don't have access to video device and
83  * this interface finds the struct video_device for the q and
84  * calls v4l_enable_media_source().
85  */
86 int v4l_vb2q_enable_media_source(struct vb2_queue *q);
87 
88 /**
89  * v4l2_create_fwnode_links_to_pad - Create fwnode-based links from a
90  *                                   source subdev to a sink pad.
91  *
92  * @src_sd: pointer to a source subdev
93  * @sink:  pointer to a sink pad
94  * @flags: the link flags
95  *
96  * This function searches for fwnode endpoint connections from a source
97  * subdevice to a single sink pad, and if suitable connections are found,
98  * translates them into media links to that pad. The function can be
99  * called by the sink, in its v4l2-async notifier bound callback, to create
100  * links from a bound source subdevice.
101  *
102  * The @flags argument specifies the link flags. The caller shall ensure that
103  * the flags are valid regardless of the number of links that may be created.
104  * For instance, setting the MEDIA_LNK_FL_ENABLED flag will cause all created
105  * links to be enabled, which isn't valid if more than one link is created.
106  *
107  * .. note::
108  *
109  *    Any sink subdevice that calls this function must implement the
110  *    .get_fwnode_pad media operation in order to verify endpoints passed
111  *    to the sink are owned by the sink.
112  *
113  * Return 0 on success or a negative error code on failure.
114  */
115 int v4l2_create_fwnode_links_to_pad(struct v4l2_subdev *src_sd,
116 				    struct media_pad *sink, u32 flags);
117 
118 /**
119  * v4l2_create_fwnode_links - Create fwnode-based links from a source
120  *                            subdev to a sink subdev.
121  *
122  * @src_sd: pointer to a source subdevice
123  * @sink_sd: pointer to a sink subdevice
124  *
125  * This function searches for any and all fwnode endpoint connections
126  * between source and sink subdevices, and translates them into media
127  * links. The function can be called by the sink subdevice, in its
128  * v4l2-async notifier subdev bound callback, to create all links from
129  * a bound source subdevice.
130  *
131  * .. note::
132  *
133  *    Any sink subdevice that calls this function must implement the
134  *    .get_fwnode_pad media operation in order to verify endpoints passed
135  *    to the sink are owned by the sink.
136  *
137  * Return 0 on success or a negative error code on failure.
138  */
139 int v4l2_create_fwnode_links(struct v4l2_subdev *src_sd,
140 			     struct v4l2_subdev *sink_sd);
141 
142 /**
143  * v4l2_pipeline_pm_get - Increase the use count of a pipeline
144  * @entity: The root entity of a pipeline
145  *
146  * Update the use count of all entities in the pipeline and power entities on.
147  *
148  * This function is intended to be called in video node open. It uses
149  * struct media_entity.use_count to track the power status. The use
150  * of this function should be paired with v4l2_pipeline_link_notify().
151  *
152  * Return 0 on success or a negative error code on failure.
153  */
154 int v4l2_pipeline_pm_get(struct media_entity *entity);
155 
156 /**
157  * v4l2_pipeline_pm_put - Decrease the use count of a pipeline
158  * @entity: The root entity of a pipeline
159  *
160  * Update the use count of all entities in the pipeline and power entities off.
161  *
162  * This function is intended to be called in video node release. It uses
163  * struct media_entity.use_count to track the power status. The use
164  * of this function should be paired with v4l2_pipeline_link_notify().
165  */
166 void v4l2_pipeline_pm_put(struct media_entity *entity);
167 
168 
169 /**
170  * v4l2_pipeline_link_notify - Link management notification callback
171  * @link: The link
172  * @flags: New link flags that will be applied
173  * @notification: The link's state change notification type (MEDIA_DEV_NOTIFY_*)
174  *
175  * React to link management on powered pipelines by updating the use count of
176  * all entities in the source and sink sides of the link. Entities are powered
177  * on or off accordingly. The use of this function should be paired
178  * with v4l2_pipeline_pm_{get,put}().
179  *
180  * Return 0 on success or a negative error code on failure. Powering entities
181  * off is assumed to never fail. This function will not fail for disconnection
182  * events.
183  */
184 int v4l2_pipeline_link_notify(struct media_link *link, u32 flags,
185 			      unsigned int notification);
186 
187 #else /* CONFIG_MEDIA_CONTROLLER */
188 
v4l2_mc_create_media_graph(struct media_device * mdev)189 static inline int v4l2_mc_create_media_graph(struct media_device *mdev)
190 {
191 	return 0;
192 }
193 
v4l_enable_media_source(struct video_device * vdev)194 static inline int v4l_enable_media_source(struct video_device *vdev)
195 {
196 	return 0;
197 }
198 
v4l_disable_media_source(struct video_device * vdev)199 static inline void v4l_disable_media_source(struct video_device *vdev)
200 {
201 }
202 
v4l_vb2q_enable_media_source(struct vb2_queue * q)203 static inline int v4l_vb2q_enable_media_source(struct vb2_queue *q)
204 {
205 	return 0;
206 }
207 
v4l2_pipeline_pm_get(struct media_entity * entity)208 static inline int v4l2_pipeline_pm_get(struct media_entity *entity)
209 {
210 	return 0;
211 }
212 
v4l2_pipeline_pm_put(struct media_entity * entity)213 static inline void v4l2_pipeline_pm_put(struct media_entity *entity)
214 {}
215 
v4l2_pipeline_link_notify(struct media_link * link,u32 flags,unsigned int notification)216 static inline int v4l2_pipeline_link_notify(struct media_link *link, u32 flags,
217 					    unsigned int notification)
218 {
219 	return 0;
220 }
221 
222 #endif /* CONFIG_MEDIA_CONTROLLER */
223 #endif /* _V4L2_MC_H */
224