include/media/v4l2-mc.h

   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 <linux/types.h>
  16
  17 /* We don't need to include pci.h or usb.h here */
  18 struct pci_dev;
  19 struct usb_device;
  20
  21 #ifdef CONFIG_MEDIA_CONTROLLER
  22 /**
  23  * v4l2_mc_create_media_graph() - create Media Controller links at the graph.
  24  *
  25  * @mdev:       pointer to the &media_device struct.
  26  *
  27  * Add links between the entities commonly found on PC customer's hardware at
  28  * the V4L2 side: camera sensors, audio and video PLL-IF decoders, tuners,
  29  * analog TV decoder and I/O entities (video, VBI and Software Defined Radio).
  30  *
  31  * .. note::
  32  *
  33  *    Webcams are modelled on a very simple way: the sensor is
  34  *    connected directly to the I/O entity. All dirty details, like
  35  *    scaler and crop HW are hidden. While such mapping is enough for v4l2
  36  *    interface centric PC-consumer's hardware, V4L2 subdev centric camera
  37  *    hardware should not use this routine, as it will not build the right graph.
  38  */
  39 int v4l2_mc_create_media_graph(struct media_device *mdev);
  40
  41 /**
  42  * v4l_enable_media_source() -  Hold media source for exclusive use
  43  *                              if free
  44  *
  45  * @vdev:       pointer to struct video_device
  46  *
  47  * This interface calls enable_source handler to determine if
  48  * media source is free for use. The enable_source handler is
  49  * responsible for checking is the media source is free and
  50  * start a pipeline between the media source and the media
  51  * entity associated with the video device. This interface
  52  * should be called from v4l2-core and dvb-core interfaces
  53  * that change the source configuration.
  54  *
  55  * Return: returns zero on success or a negative error code.
  56  */
  57 int v4l_enable_media_source(struct video_device *vdev);
  58
  59 /**
  60  * v4l_disable_media_source() - Release media source
  61  *
  62  * @vdev:       pointer to struct video_device
  63  *
  64  * This interface calls disable_source handler to release
  65  * the media source. The disable_source handler stops the
  66  * active media pipeline between the media source and the
  67  * media entity associated with the video device.
  68  *
  69  * Return: returns zero on success or a negative error code.
  70  */
  71 void v4l_disable_media_source(struct video_device *vdev);
  72
  73 /*
  74  * v4l_vb2q_enable_media_tuner -  Hold media source for exclusive use
  75  *                                if free.
  76  * @q - pointer to struct vb2_queue
  77  *
  78  * Wrapper for v4l_enable_media_source(). This function should
  79  * be called from v4l2-core to enable the media source with
  80  * pointer to struct vb2_queue as the input argument. Some
  81  * v4l2-core interfaces don't have access to video device and
  82  * this interface finds the struct video_device for the q and
  83  * calls v4l_enable_media_source().
  84  */
  85 int v4l_vb2q_enable_media_source(struct vb2_queue *q);
  86
  87
  88 /**
  89  * v4l2_pipeline_pm_use - Update the use count of an entity
  90  * @entity: The entity
  91  * @use: Use (1) or stop using (0) the entity
  92  *
  93  * Update the use count of all entities in the pipeline and power entities on or
  94  * off accordingly.
  95  *
  96  * This function is intended to be called in video node open (use ==
  97  * 1) and release (use == 0). It uses struct media_entity.use_count to
  98  * track the power status. The use of this function should be paired
  99  * with v4l2_pipeline_link_notify().
 100  *
 101  * Return 0 on success or a negative error code on failure. Powering entities
 102  * off is assumed to never fail. No failure can occur when the use parameter is
 103  * set to 0.
 104  */
 105 int v4l2_pipeline_pm_use(struct media_entity *entity, int use);
 106
 107
 108 /**
 109  * v4l2_pipeline_link_notify - Link management notification callback
 110  * @link: The link
 111  * @flags: New link flags that will be applied
 112  * @notification: The link's state change notification type (MEDIA_DEV_NOTIFY_*)
 113  *
 114  * React to link management on powered pipelines by updating the use count of
 115  * all entities in the source and sink sides of the link. Entities are powered
 116  * on or off accordingly. The use of this function should be paired
 117  * with v4l2_pipeline_pm_use().
 118  *
 119  * Return 0 on success or a negative error code on failure. Powering entities
 120  * off is assumed to never fail. This function will not fail for disconnection
 121  * events.
 122  */
 123 int v4l2_pipeline_link_notify(struct media_link *link, u32 flags,
 124                               unsigned int notification);
 125
 126 #else /* CONFIG_MEDIA_CONTROLLER */
 127
 128 static inline int v4l2_mc_create_media_graph(struct media_device *mdev)
 129 {
 130         return 0;
 131 }
 132
 133 static inline int v4l_enable_media_source(struct video_device *vdev)
 134 {
 135         return 0;
 136 }
 137
 138 static inline void v4l_disable_media_source(struct video_device *vdev)
 139 {
 140 }
 141
 142 static inline int v4l_vb2q_enable_media_source(struct vb2_queue *q)
 143 {
 144         return 0;
 145 }
 146
 147 static inline int v4l2_pipeline_pm_use(struct media_entity *entity, int use)
 148 {
 149         return 0;
 150 }
 151
 152 static inline int v4l2_pipeline_link_notify(struct media_link *link, u32 flags,
 153                                             unsigned int notification)
 154 {
 155         return 0;
 156 }
 157
 158 #endif /* CONFIG_MEDIA_CONTROLLER */
 159 #endif /* _V4L2_MC_H */