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 backlight_device;
32 struct dentry;
33 struct device_node;
34 struct drm_connector;
35 struct drm_device;
36 struct drm_panel;
37 struct display_timing;
38 
39 enum drm_panel_orientation;
40 
41 /**
42  * struct drm_panel_funcs - perform operations on a given panel
43  *
44  * The .prepare() function is typically called before the display controller
45  * starts to transmit video data. Panel drivers can use this to turn the panel
46  * on and wait for it to become ready. If additional configuration is required
47  * (via a control bus such as I2C, SPI or DSI for example) this is a good time
48  * to do that.
49  *
50  * After the display controller has started transmitting video data, it's safe
51  * to call the .enable() function. This will typically enable the backlight to
52  * make the image on screen visible. Some panels require a certain amount of
53  * time or frames before the image is displayed. This function is responsible
54  * for taking this into account before enabling the backlight to avoid visual
55  * glitches.
56  *
57  * Before stopping video transmission from the display controller it can be
58  * necessary to turn off the panel to avoid visual glitches. This is done in
59  * the .disable() function. Analogously to .enable() this typically involves
60  * turning off the backlight and waiting for some time to make sure no image
61  * is visible on the panel. It is then safe for the display controller to
62  * cease transmission of video data.
63  *
64  * To save power when no video data is transmitted, a driver can power down
65  * the panel. This is the job of the .unprepare() function.
66  *
67  * Backlight can be handled automatically if configured using
68  * drm_panel_of_backlight() or drm_panel_dp_aux_backlight(). Then the driver
69  * does not need to implement the functionality to enable/disable backlight.
70  */
71 struct drm_panel_funcs {
72 	/**
73 	 * @prepare:
74 	 *
75 	 * Turn on panel and perform set up.
76 	 *
77 	 * This function is optional.
78 	 */
79 	int (*prepare)(struct drm_panel *panel);
80 
81 	/**
82 	 * @enable:
83 	 *
84 	 * Enable panel (turn on back light, etc.).
85 	 *
86 	 * This function is optional.
87 	 */
88 	int (*enable)(struct drm_panel *panel);
89 
90 	/**
91 	 * @disable:
92 	 *
93 	 * Disable panel (turn off back light, etc.).
94 	 *
95 	 * This function is optional.
96 	 */
97 	int (*disable)(struct drm_panel *panel);
98 
99 	/**
100 	 * @unprepare:
101 	 *
102 	 * Turn off panel.
103 	 *
104 	 * This function is optional.
105 	 */
106 	int (*unprepare)(struct drm_panel *panel);
107 
108 	/**
109 	 * @get_modes:
110 	 *
111 	 * Add modes to the connector that the panel is attached to
112 	 * and returns the number of modes added.
113 	 *
114 	 * This function is mandatory.
115 	 */
116 	int (*get_modes)(struct drm_panel *panel,
117 			 struct drm_connector *connector);
118 
119 	/**
120 	 * @get_orientation:
121 	 *
122 	 * Return the panel orientation set by device tree or EDID.
123 	 *
124 	 * This function is optional.
125 	 */
126 	enum drm_panel_orientation (*get_orientation)(struct drm_panel *panel);
127 
128 	/**
129 	 * @get_timings:
130 	 *
131 	 * Copy display timings into the provided array and return
132 	 * the number of display timings available.
133 	 *
134 	 * This function is optional.
135 	 */
136 	int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
137 			   struct display_timing *timings);
138 
139 	/**
140 	 * @debugfs_init:
141 	 *
142 	 * Allows panels to create panels-specific debugfs files.
143 	 */
144 	void (*debugfs_init)(struct drm_panel *panel, struct dentry *root);
145 };
146 
147 /**
148  * struct drm_panel - DRM panel object
149  */
150 struct drm_panel {
151 	/**
152 	 * @dev:
153 	 *
154 	 * Parent device of the panel.
155 	 */
156 	struct device *dev;
157 
158 	/**
159 	 * @backlight:
160 	 *
161 	 * Backlight device, used to turn on backlight after the call
162 	 * to enable(), and to turn off backlight before the call to
163 	 * disable().
164 	 * backlight is set by drm_panel_of_backlight() or
165 	 * drm_panel_dp_aux_backlight() and drivers shall not assign it.
166 	 */
167 	struct backlight_device *backlight;
168 
169 	/**
170 	 * @funcs:
171 	 *
172 	 * Operations that can be performed on the panel.
173 	 */
174 	const struct drm_panel_funcs *funcs;
175 
176 	/**
177 	 * @connector_type:
178 	 *
179 	 * Type of the panel as a DRM_MODE_CONNECTOR_* value. This is used to
180 	 * initialise the drm_connector corresponding to the panel with the
181 	 * correct connector type.
182 	 */
183 	int connector_type;
184 
185 	/**
186 	 * @list:
187 	 *
188 	 * Panel entry in registry.
189 	 */
190 	struct list_head list;
191 };
192 
193 void drm_panel_init(struct drm_panel *panel, struct device *dev,
194 		    const struct drm_panel_funcs *funcs,
195 		    int connector_type);
196 
197 void drm_panel_add(struct drm_panel *panel);
198 void drm_panel_remove(struct drm_panel *panel);
199 
200 int drm_panel_prepare(struct drm_panel *panel);
201 int drm_panel_unprepare(struct drm_panel *panel);
202 
203 int drm_panel_enable(struct drm_panel *panel);
204 int drm_panel_disable(struct drm_panel *panel);
205 
206 int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
207 
208 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
209 struct drm_panel *of_drm_find_panel(const struct device_node *np);
210 int of_drm_get_panel_orientation(const struct device_node *np,
211 				 enum drm_panel_orientation *orientation);
212 #else
of_drm_find_panel(const struct device_node * np)213 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
214 {
215 	return ERR_PTR(-ENODEV);
216 }
217 
of_drm_get_panel_orientation(const struct device_node * np,enum drm_panel_orientation * orientation)218 static inline int of_drm_get_panel_orientation(const struct device_node *np,
219 					       enum drm_panel_orientation *orientation)
220 {
221 	return -ENODEV;
222 }
223 #endif
224 
225 #if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
226 	(IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))
227 int drm_panel_of_backlight(struct drm_panel *panel);
228 #else
drm_panel_of_backlight(struct drm_panel * panel)229 static inline int drm_panel_of_backlight(struct drm_panel *panel)
230 {
231 	return 0;
232 }
233 #endif
234 
235 #endif
236