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/err.h>
28 #include <linux/errno.h>
29 #include <linux/list.h>
30
31 struct device_node;
32 struct drm_connector;
33 struct drm_device;
34 struct drm_panel;
35 struct display_timing;
36
37 /**
38 * struct drm_panel_funcs - perform operations on a given panel
39 * @disable: disable panel (turn off back light, etc.)
40 * @unprepare: turn off panel
41 * @prepare: turn on panel and perform set up
42 * @enable: enable panel (turn on back light, etc.)
43 * @get_modes: add modes to the connector that the panel is attached to and
44 * return the number of modes added
45 * @get_timings: copy display timings into the provided array and return
46 * the number of display timings available
47 *
48 * The .prepare() function is typically called before the display controller
49 * starts to transmit video data. Panel drivers can use this to turn the panel
50 * on and wait for it to become ready. If additional configuration is required
51 * (via a control bus such as I2C, SPI or DSI for example) this is a good time
52 * to do that.
53 *
54 * After the display controller has started transmitting video data, it's safe
55 * to call the .enable() function. This will typically enable the backlight to
56 * make the image on screen visible. Some panels require a certain amount of
57 * time or frames before the image is displayed. This function is responsible
58 * for taking this into account before enabling the backlight to avoid visual
59 * glitches.
60 *
61 * Before stopping video transmission from the display controller it can be
62 * necessary to turn off the panel to avoid visual glitches. This is done in
63 * the .disable() function. Analogously to .enable() this typically involves
64 * turning off the backlight and waiting for some time to make sure no image
65 * is visible on the panel. It is then safe for the display controller to
66 * cease transmission of video data.
67 *
68 * To save power when no video data is transmitted, a driver can power down
69 * the panel. This is the job of the .unprepare() function.
70 */
71 struct drm_panel_funcs {
72 int (*disable)(struct drm_panel *panel);
73 int (*unprepare)(struct drm_panel *panel);
74 int (*prepare)(struct drm_panel *panel);
75 int (*enable)(struct drm_panel *panel);
76 int (*get_modes)(struct drm_panel *panel);
77 int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
78 struct display_timing *timings);
79 };
80
81 /**
82 * struct drm_panel - DRM panel object
83 * @drm: DRM device owning the panel
84 * @connector: DRM connector that the panel is attached to
85 * @dev: parent device of the panel
86 * @funcs: operations that can be performed on the panel
87 * @list: panel entry in registry
88 */
89 struct drm_panel {
90 struct drm_device *drm;
91 struct drm_connector *connector;
92 struct device *dev;
93
94 const struct drm_panel_funcs *funcs;
95
96 struct list_head list;
97 };
98
99 /**
100 * drm_disable_unprepare - power off a panel
101 * @panel: DRM panel
102 *
103 * Calling this function will completely power off a panel (assert the panel's
104 * reset, turn off power supplies, ...). After this function has completed, it
105 * is usually no longer possible to communicate with the panel until another
106 * call to drm_panel_prepare().
107 *
108 * Return: 0 on success or a negative error code on failure.
109 */
drm_panel_unprepare(struct drm_panel * panel)110 static inline int drm_panel_unprepare(struct drm_panel *panel)
111 {
112 if (panel && panel->funcs && panel->funcs->unprepare)
113 return panel->funcs->unprepare(panel);
114
115 return panel ? -ENOSYS : -EINVAL;
116 }
117
118 /**
119 * drm_panel_disable - disable a panel
120 * @panel: DRM panel
121 *
122 * This will typically turn off the panel's backlight or disable the display
123 * drivers. For smart panels it should still be possible to communicate with
124 * the integrated circuitry via any command bus after this call.
125 *
126 * Return: 0 on success or a negative error code on failure.
127 */
drm_panel_disable(struct drm_panel * panel)128 static inline int drm_panel_disable(struct drm_panel *panel)
129 {
130 if (panel && panel->funcs && panel->funcs->disable)
131 return panel->funcs->disable(panel);
132
133 return panel ? -ENOSYS : -EINVAL;
134 }
135
136 /**
137 * drm_panel_prepare - power on a panel
138 * @panel: DRM panel
139 *
140 * Calling this function will enable power and deassert any reset signals to
141 * the panel. After this has completed it is possible to communicate with any
142 * integrated circuitry via a command bus.
143 *
144 * Return: 0 on success or a negative error code on failure.
145 */
drm_panel_prepare(struct drm_panel * panel)146 static inline int drm_panel_prepare(struct drm_panel *panel)
147 {
148 if (panel && panel->funcs && panel->funcs->prepare)
149 return panel->funcs->prepare(panel);
150
151 return panel ? -ENOSYS : -EINVAL;
152 }
153
154 /**
155 * drm_panel_enable - enable a panel
156 * @panel: DRM panel
157 *
158 * Calling this function will cause the panel display drivers to be turned on
159 * and the backlight to be enabled. Content will be visible on screen after
160 * this call completes.
161 *
162 * Return: 0 on success or a negative error code on failure.
163 */
drm_panel_enable(struct drm_panel * panel)164 static inline int drm_panel_enable(struct drm_panel *panel)
165 {
166 if (panel && panel->funcs && panel->funcs->enable)
167 return panel->funcs->enable(panel);
168
169 return panel ? -ENOSYS : -EINVAL;
170 }
171
172 /**
173 * drm_panel_get_modes - probe the available display modes of a panel
174 * @panel: DRM panel
175 *
176 * The modes probed from the panel are automatically added to the connector
177 * that the panel is attached to.
178 *
179 * Return: The number of modes available from the panel on success or a
180 * negative error code on failure.
181 */
drm_panel_get_modes(struct drm_panel * panel)182 static inline int drm_panel_get_modes(struct drm_panel *panel)
183 {
184 if (panel && panel->funcs && panel->funcs->get_modes)
185 return panel->funcs->get_modes(panel);
186
187 return panel ? -ENOSYS : -EINVAL;
188 }
189
190 void drm_panel_init(struct drm_panel *panel);
191
192 int drm_panel_add(struct drm_panel *panel);
193 void drm_panel_remove(struct drm_panel *panel);
194
195 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector);
196 int drm_panel_detach(struct drm_panel *panel);
197
198 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
199 struct drm_panel *of_drm_find_panel(const struct device_node *np);
200 #else
of_drm_find_panel(const struct device_node * np)201 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
202 {
203 return ERR_PTR(-ENODEV);
204 }
205 #endif
206
207 #endif
208