1 /* SPDX-License-Identifier: MIT */
2 /*
3  * Copyright (C) 2020 Red Hat, Inc.
4  *
5  * Authors:
6  * Hans de Goede <hdegoede@redhat.com>
7  */
8 
9 #ifndef __DRM_PRIVACY_SCREEN_DRIVER_H__
10 #define __DRM_PRIVACY_SCREEN_DRIVER_H__
11 
12 #include <linux/device.h>
13 #include <linux/list.h>
14 #include <linux/mutex.h>
15 #include <drm/drm_connector.h>
16 
17 struct drm_privacy_screen;
18 
19 /**
20  * struct drm_privacy_screen_ops - drm_privacy_screen operations
21  *
22  * Defines the operations which the privacy-screen class code may call.
23  * These functions should be implemented by the privacy-screen driver.
24  */
25 struct drm_privacy_screen_ops {
26 	/**
27 	 * @set_sw_state: Called to request a change of the privacy-screen
28 	 * state. The privacy-screen class code contains a check to avoid this
29 	 * getting called when the hw_state reports the state is locked.
30 	 * It is the driver's responsibility to update sw_state and hw_state.
31 	 * This is always called with the drm_privacy_screen's lock held.
32 	 */
33 	int (*set_sw_state)(struct drm_privacy_screen *priv,
34 			    enum drm_privacy_screen_status sw_state);
35 	/**
36 	 * @get_hw_state: Called to request that the driver gets the current
37 	 * privacy-screen state from the hardware and then updates sw_state and
38 	 * hw_state accordingly. This will be called by the core just before
39 	 * the privacy-screen is registered in sysfs.
40 	 */
41 	void (*get_hw_state)(struct drm_privacy_screen *priv);
42 };
43 
44 /**
45  * struct drm_privacy_screen - central privacy-screen structure
46  *
47  * Central privacy-screen structure, this contains the struct device used
48  * to register the screen in sysfs, the screen's state, ops, etc.
49  */
50 struct drm_privacy_screen {
51 	/** @dev: device used to register the privacy-screen in sysfs. */
52 	struct device dev;
53 	/** @lock: mutex protection all fields in this struct. */
54 	struct mutex lock;
55 	/** @list: privacy-screen devices list list-entry. */
56 	struct list_head list;
57 	/** @notifier_head: privacy-screen notifier head. */
58 	struct blocking_notifier_head notifier_head;
59 	/**
60 	 * @ops: &struct drm_privacy_screen_ops for this privacy-screen.
61 	 * This is NULL if the driver has unregistered the privacy-screen.
62 	 */
63 	const struct drm_privacy_screen_ops *ops;
64 	/**
65 	 * @sw_state: The privacy-screen's software state, see
66 	 * :ref:`Standard Connector Properties<standard_connector_properties>`
67 	 * for more info.
68 	 */
69 	enum drm_privacy_screen_status sw_state;
70 	/**
71 	 * @hw_state: The privacy-screen's hardware state, see
72 	 * :ref:`Standard Connector Properties<standard_connector_properties>`
73 	 * for more info.
74 	 */
75 	enum drm_privacy_screen_status hw_state;
76 };
77 
78 struct drm_privacy_screen *drm_privacy_screen_register(
79 	struct device *parent, const struct drm_privacy_screen_ops *ops);
80 void drm_privacy_screen_unregister(struct drm_privacy_screen *priv);
81 
82 void drm_privacy_screen_call_notifier_chain(struct drm_privacy_screen *priv);
83 
84 #endif
85