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/errno.h>
28 #include <linux/list.h>
29
30 struct device_node;
31 struct drm_connector;
32 struct drm_device;
33 struct drm_panel;
34 struct display_timing;
35
36 /**
37 * struct drm_panel_funcs - perform operations on a given panel
38 * @disable: disable panel (turn off back light, etc.)
39 * @unprepare: turn off panel
40 * @prepare: turn on panel and perform set up
41 * @enable: enable panel (turn on back light, etc.)
42 * @get_modes: add modes to the connector that the panel is attached to and
43 * return the number of modes added
44 * @get_timings: copy display timings into the provided array and return
45 * the number of display timings available
46 *
47 * The .prepare() function is typically called before the display controller
48 * starts to transmit video data. Panel drivers can use this to turn the panel
49 * on and wait for it to become ready. If additional configuration is required
50 * (via a control bus such as I2C, SPI or DSI for example) this is a good time
51 * to do that.
52 *
53 * After the display controller has started transmitting video data, it's safe
54 * to call the .enable() function. This will typically enable the backlight to
55 * make the image on screen visible. Some panels require a certain amount of
56 * time or frames before the image is displayed. This function is responsible
57 * for taking this into account before enabling the backlight to avoid visual
58 * glitches.
59 *
60 * Before stopping video transmission from the display controller it can be
61 * necessary to turn off the panel to avoid visual glitches. This is done in
62 * the .disable() function. Analogously to .enable() this typically involves
63 * turning off the backlight and waiting for some time to make sure no image
64 * is visible on the panel. It is then safe for the display controller to
65 * cease transmission of video data.
66 *
67 * To save power when no video data is transmitted, a driver can power down
68 * the panel. This is the job of the .unprepare() function.
69 */
70 struct drm_panel_funcs {
71 int (*disable)(struct drm_panel *panel);
72 int (*unprepare)(struct drm_panel *panel);
73 int (*prepare)(struct drm_panel *panel);
74 int (*enable)(struct drm_panel *panel);
75 int (*get_modes)(struct drm_panel *panel);
76 int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
77 struct display_timing *timings);
78 };
79
80 /**
81 * struct drm_panel - DRM panel object
82 * @drm: DRM device owning the panel
83 * @connector: DRM connector that the panel is attached to
84 * @dev: parent device of the panel
85 * @funcs: operations that can be performed on the panel
86 * @list: panel entry in registry
87 */
88 struct drm_panel {
89 struct drm_device *drm;
90 struct drm_connector *connector;
91 struct device *dev;
92
93 const struct drm_panel_funcs *funcs;
94
95 struct list_head list;
96 };
97
98 /**
99 * drm_disable_unprepare - power off a panel
100 * @panel: DRM panel
101 *
102 * Calling this function will completely power off a panel (assert the panel's
103 * reset, turn off power supplies, ...). After this function has completed, it
104 * is usually no longer possible to communicate with the panel until another
105 * call to drm_panel_prepare().
106 *
107 * Return: 0 on success or a negative error code on failure.
108 */
drm_panel_unprepare(struct drm_panel * panel)109 static inline int drm_panel_unprepare(struct drm_panel *panel)
110 {
111 if (panel && panel->funcs && panel->funcs->unprepare)
112 return panel->funcs->unprepare(panel);
113
114 return panel ? -ENOSYS : -EINVAL;
115 }
116
117 /**
118 * drm_panel_disable - disable a panel
119 * @panel: DRM panel
120 *
121 * This will typically turn off the panel's backlight or disable the display
122 * drivers. For smart panels it should still be possible to communicate with
123 * the integrated circuitry via any command bus after this call.
124 *
125 * Return: 0 on success or a negative error code on failure.
126 */
drm_panel_disable(struct drm_panel * panel)127 static inline int drm_panel_disable(struct drm_panel *panel)
128 {
129 if (panel && panel->funcs && panel->funcs->disable)
130 return panel->funcs->disable(panel);
131
132 return panel ? -ENOSYS : -EINVAL;
133 }
134
135 /**
136 * drm_panel_prepare - power on a panel
137 * @panel: DRM panel
138 *
139 * Calling this function will enable power and deassert any reset signals to
140 * the panel. After this has completed it is possible to communicate with any
141 * integrated circuitry via a command bus.
142 *
143 * Return: 0 on success or a negative error code on failure.
144 */
drm_panel_prepare(struct drm_panel * panel)145 static inline int drm_panel_prepare(struct drm_panel *panel)
146 {
147 if (panel && panel->funcs && panel->funcs->prepare)
148 return panel->funcs->prepare(panel);
149
150 return panel ? -ENOSYS : -EINVAL;
151 }
152
153 /**
154 * drm_panel_enable - enable a panel
155 * @panel: DRM panel
156 *
157 * Calling this function will cause the panel display drivers to be turned on
158 * and the backlight to be enabled. Content will be visible on screen after
159 * this call completes.
160 *
161 * Return: 0 on success or a negative error code on failure.
162 */
drm_panel_enable(struct drm_panel * panel)163 static inline int drm_panel_enable(struct drm_panel *panel)
164 {
165 if (panel && panel->funcs && panel->funcs->enable)
166 return panel->funcs->enable(panel);
167
168 return panel ? -ENOSYS : -EINVAL;
169 }
170
171 /**
172 * drm_panel_get_modes - probe the available display modes of a panel
173 * @panel: DRM panel
174 *
175 * The modes probed from the panel are automatically added to the connector
176 * that the panel is attached to.
177 *
178 * Return: The number of modes available from the panel on success or a
179 * negative error code on failure.
180 */
drm_panel_get_modes(struct drm_panel * panel)181 static inline int drm_panel_get_modes(struct drm_panel *panel)
182 {
183 if (panel && panel->funcs && panel->funcs->get_modes)
184 return panel->funcs->get_modes(panel);
185
186 return panel ? -ENOSYS : -EINVAL;
187 }
188
189 void drm_panel_init(struct drm_panel *panel);
190
191 int drm_panel_add(struct drm_panel *panel);
192 void drm_panel_remove(struct drm_panel *panel);
193
194 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector);
195 int drm_panel_detach(struct drm_panel *panel);
196
197 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
198 struct drm_panel *of_drm_find_panel(const struct device_node *np);
199 #else
of_drm_find_panel(const struct device_node * np)200 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
201 {
202 return ERR_PTR(-ENODEV);
203 }
204 #endif
205
206 #endif
207
