1 /* $NetBSD: drm_panel.h,v 1.4 2021/12/18 23:45:46 riastradh Exp $ */
2
3 /*
4 * Copyright (C) 2013, NVIDIA Corporation. All rights reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the "Software"),
8 * to deal in the Software without restriction, including without limitation
9 * the rights to use, copy, modify, merge, publish, distribute, sub license,
10 * and/or sell copies of the Software, and to permit persons to whom the
11 * Software is furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice (including the
14 * next paragraph) shall be included in all copies or substantial portions
15 * of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
23 * DEALINGS IN THE SOFTWARE.
24 */
25
26 #ifndef __DRM_PANEL_H__
27 #define __DRM_PANEL_H__
28
29 #include <linux/err.h>
30 #include <linux/errno.h>
31 #include <linux/list.h>
32
33 struct backlight_device;
34 struct device_node;
35 struct drm_connector;
36 struct drm_device;
37 struct drm_panel;
38 struct display_timing;
39
40 /**
41 * struct drm_panel_funcs - perform operations on a given panel
42 *
43 * The .prepare() function is typically called before the display controller
44 * starts to transmit video data. Panel drivers can use this to turn the panel
45 * on and wait for it to become ready. If additional configuration is required
46 * (via a control bus such as I2C, SPI or DSI for example) this is a good time
47 * to do that.
48 *
49 * After the display controller has started transmitting video data, it's safe
50 * to call the .enable() function. This will typically enable the backlight to
51 * make the image on screen visible. Some panels require a certain amount of
52 * time or frames before the image is displayed. This function is responsible
53 * for taking this into account before enabling the backlight to avoid visual
54 * glitches.
55 *
56 * Before stopping video transmission from the display controller it can be
57 * necessary to turn off the panel to avoid visual glitches. This is done in
58 * the .disable() function. Analogously to .enable() this typically involves
59 * turning off the backlight and waiting for some time to make sure no image
60 * is visible on the panel. It is then safe for the display controller to
61 * cease transmission of video data.
62 *
63 * To save power when no video data is transmitted, a driver can power down
64 * the panel. This is the job of the .unprepare() function.
65 *
66 * Backlight can be handled automatically if configured using
67 * drm_panel_of_backlight(). Then the driver does not need to implement the
68 * functionality to enable/disable backlight.
69 */
70 struct drm_panel_funcs {
71 /**
72 * @prepare:
73 *
74 * Turn on panel and perform set up.
75 *
76 * This function is optional.
77 */
78 int (*prepare)(struct drm_panel *panel);
79
80 /**
81 * @enable:
82 *
83 * Enable panel (turn on back light, etc.).
84 *
85 * This function is optional.
86 */
87 int (*enable)(struct drm_panel *panel);
88
89 /**
90 * @disable:
91 *
92 * Disable panel (turn off back light, etc.).
93 *
94 * This function is optional.
95 */
96 int (*disable)(struct drm_panel *panel);
97
98 /**
99 * @unprepare:
100 *
101 * Turn off panel.
102 *
103 * This function is optional.
104 */
105 int (*unprepare)(struct drm_panel *panel);
106
107 /**
108 * @get_modes:
109 *
110 * Add modes to the connector that the panel is attached to
111 * and returns the number of modes added.
112 *
113 * This function is mandatory.
114 */
115 int (*get_modes)(struct drm_panel *panel,
116 struct drm_connector *connector);
117
118 /**
119 * @get_timings:
120 *
121 * Copy display timings into the provided array and return
122 * the number of display timings available.
123 *
124 * This function is optional.
125 */
126 int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
127 struct display_timing *timings);
128 };
129
130 /**
131 * struct drm_panel - DRM panel object
132 */
133 struct drm_panel {
134 /**
135 * @dev:
136 *
137 * Parent device of the panel.
138 */
139 struct device *dev;
140
141 /**
142 * @backlight:
143 *
144 * Backlight device, used to turn on backlight after the call
145 * to enable(), and to turn off backlight before the call to
146 * disable().
147 * backlight is set by drm_panel_of_backlight() and drivers
148 * shall not assign it.
149 */
150 struct backlight_device *backlight;
151
152 /**
153 * @funcs:
154 *
155 * Operations that can be performed on the panel.
156 */
157 const struct drm_panel_funcs *funcs;
158
159 /**
160 * @connector_type:
161 *
162 * Type of the panel as a DRM_MODE_CONNECTOR_* value. This is used to
163 * initialise the drm_connector corresponding to the panel with the
164 * correct connector type.
165 */
166 int connector_type;
167
168 /**
169 * @list:
170 *
171 * Panel entry in registry.
172 */
173 struct list_head list;
174 };
175
176 #ifdef __NetBSD__
177 void drm_panel_init_lock(void);
178 void drm_panel_fini_lock(void);
179 #endif
180
181 void drm_panel_init(struct drm_panel *panel, struct device *dev,
182 const struct drm_panel_funcs *funcs,
183 int connector_type);
184
185 int drm_panel_add(struct drm_panel *panel);
186 void drm_panel_remove(struct drm_panel *panel);
187
188 int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector);
189 void drm_panel_detach(struct drm_panel *panel);
190
191 int drm_panel_prepare(struct drm_panel *panel);
192 int drm_panel_unprepare(struct drm_panel *panel);
193
194 int drm_panel_enable(struct drm_panel *panel);
195 int drm_panel_disable(struct drm_panel *panel);
196
197 int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
198
199 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
200 struct drm_panel *of_drm_find_panel(const struct device_node *np);
201 #else
of_drm_find_panel(const struct device_node * np)202 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
203 {
204 return ERR_PTR(-ENODEV);
205 }
206 #endif
207
208 #if IS_REACHABLE(CONFIG_BACKLIGHT_CLASS_DEVICE)
209 int drm_panel_of_backlight(struct drm_panel *panel);
210 #else
drm_panel_of_backlight(struct drm_panel * panel)211 static inline int drm_panel_of_backlight(struct drm_panel *panel)
212 {
213 return 0;
214 }
215 #endif
216
217 #endif
218