xref: /openbmc/linux/include/drm/drm_panel.h (revision aac5987a)
1 /*
2  * Copyright (C) 2013, NVIDIA Corporation.  All rights reserved.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sub license,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice (including the
12  * next paragraph) shall be included in all copies or substantial portions
13  * of the Software.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21  * DEALINGS IN THE SOFTWARE.
22  */
23 
24 #ifndef __DRM_PANEL_H__
25 #define __DRM_PANEL_H__
26 
27 #include <linux/list.h>
28 
29 struct drm_connector;
30 struct drm_device;
31 struct drm_panel;
32 struct display_timing;
33 
34 /**
35  * struct drm_panel_funcs - perform operations on a given panel
36  * @disable: disable panel (turn off back light, etc.)
37  * @unprepare: turn off panel
38  * @prepare: turn on panel and perform set up
39  * @enable: enable panel (turn on back light, etc.)
40  * @get_modes: add modes to the connector that the panel is attached to and
41  * return the number of modes added
42  * @get_timings: copy display timings into the provided array and return
43  * the number of display timings available
44  *
45  * The .prepare() function is typically called before the display controller
46  * starts to transmit video data. Panel drivers can use this to turn the panel
47  * on and wait for it to become ready. If additional configuration is required
48  * (via a control bus such as I2C, SPI or DSI for example) this is a good time
49  * to do that.
50  *
51  * After the display controller has started transmitting video data, it's safe
52  * to call the .enable() function. This will typically enable the backlight to
53  * make the image on screen visible. Some panels require a certain amount of
54  * time or frames before the image is displayed. This function is responsible
55  * for taking this into account before enabling the backlight to avoid visual
56  * glitches.
57  *
58  * Before stopping video transmission from the display controller it can be
59  * necessary to turn off the panel to avoid visual glitches. This is done in
60  * the .disable() function. Analogously to .enable() this typically involves
61  * turning off the backlight and waiting for some time to make sure no image
62  * is visible on the panel. It is then safe for the display controller to
63  * cease transmission of video data.
64  *
65  * To save power when no video data is transmitted, a driver can power down
66  * the panel. This is the job of the .unprepare() function.
67  */
68 struct drm_panel_funcs {
69 	int (*disable)(struct drm_panel *panel);
70 	int (*unprepare)(struct drm_panel *panel);
71 	int (*prepare)(struct drm_panel *panel);
72 	int (*enable)(struct drm_panel *panel);
73 	int (*get_modes)(struct drm_panel *panel);
74 	int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
75 			   struct display_timing *timings);
76 };
77 
78 /**
79  * struct drm_panel - DRM panel object
80  * @drm: DRM device owning the panel
81  * @connector: DRM connector that the panel is attached to
82  * @dev: parent device of the panel
83  * @funcs: operations that can be performed on the panel
84  * @list: panel entry in registry
85  */
86 struct drm_panel {
87 	struct drm_device *drm;
88 	struct drm_connector *connector;
89 	struct device *dev;
90 
91 	const struct drm_panel_funcs *funcs;
92 
93 	struct list_head list;
94 };
95 
96 /**
97  * drm_disable_unprepare - power off a panel
98  * @panel: DRM panel
99  *
100  * Calling this function will completely power off a panel (assert the panel's
101  * reset, turn off power supplies, ...). After this function has completed, it
102  * is usually no longer possible to communicate with the panel until another
103  * call to drm_panel_prepare().
104  *
105  * Return: 0 on success or a negative error code on failure.
106  */
107 static inline int drm_panel_unprepare(struct drm_panel *panel)
108 {
109 	if (panel && panel->funcs && panel->funcs->unprepare)
110 		return panel->funcs->unprepare(panel);
111 
112 	return panel ? -ENOSYS : -EINVAL;
113 }
114 
115 /**
116  * drm_panel_disable - disable a panel
117  * @panel: DRM panel
118  *
119  * This will typically turn off the panel's backlight or disable the display
120  * drivers. For smart panels it should still be possible to communicate with
121  * the integrated circuitry via any command bus after this call.
122  *
123  * Return: 0 on success or a negative error code on failure.
124  */
125 static inline int drm_panel_disable(struct drm_panel *panel)
126 {
127 	if (panel && panel->funcs && panel->funcs->disable)
128 		return panel->funcs->disable(panel);
129 
130 	return panel ? -ENOSYS : -EINVAL;
131 }
132 
133 /**
134  * drm_panel_prepare - power on a panel
135  * @panel: DRM panel
136  *
137  * Calling this function will enable power and deassert any reset signals to
138  * the panel. After this has completed it is possible to communicate with any
139  * integrated circuitry via a command bus.
140  *
141  * Return: 0 on success or a negative error code on failure.
142  */
143 static inline int drm_panel_prepare(struct drm_panel *panel)
144 {
145 	if (panel && panel->funcs && panel->funcs->prepare)
146 		return panel->funcs->prepare(panel);
147 
148 	return panel ? -ENOSYS : -EINVAL;
149 }
150 
151 /**
152  * drm_panel_enable - enable a panel
153  * @panel: DRM panel
154  *
155  * Calling this function will cause the panel display drivers to be turned on
156  * and the backlight to be enabled. Content will be visible on screen after
157  * this call completes.
158  *
159  * Return: 0 on success or a negative error code on failure.
160  */
161 static inline int drm_panel_enable(struct drm_panel *panel)
162 {
163 	if (panel && panel->funcs && panel->funcs->enable)
164 		return panel->funcs->enable(panel);
165 
166 	return panel ? -ENOSYS : -EINVAL;
167 }
168 
169 /**
170  * drm_panel_get_modes - probe the available display modes of a panel
171  * @panel: DRM panel
172  *
173  * The modes probed from the panel are automatically added to the connector
174  * that the panel is attached to.
175  *
176  * Return: The number of modes available from the panel on success or a
177  * negative error code on failure.
178  */
179 static inline int drm_panel_get_modes(struct drm_panel *panel)
180 {
181 	if (panel && panel->funcs && panel->funcs->get_modes)
182 		return panel->funcs->get_modes(panel);
183 
184 	return panel ? -ENOSYS : -EINVAL;
185 }
186 
187 void drm_panel_init(struct drm_panel *panel);
188 
189 int drm_panel_add(struct drm_panel *panel);
190 void drm_panel_remove(struct drm_panel *panel);
191 
192 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector);
193 int drm_panel_detach(struct drm_panel *panel);
194 
195 #ifdef CONFIG_OF
196 struct drm_panel *of_drm_find_panel(const struct device_node *np);
197 #else
198 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
199 {
200 	return NULL;
201 }
202 #endif
203 
204 #endif
205