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