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 #include <linux/mutex.h>
31
32 struct backlight_device;
33 struct dentry;
34 struct device_node;
35 struct drm_connector;
36 struct drm_device;
37 struct drm_panel_follower;
38 struct drm_panel;
39 struct display_timing;
40
41 enum drm_panel_orientation;
42
43 /**
44 * struct drm_panel_funcs - perform operations on a given panel
45 *
46 * The .prepare() function is typically called before the display controller
47 * starts to transmit video data. Panel drivers can use this to turn the panel
48 * on and wait for it to become ready. If additional configuration is required
49 * (via a control bus such as I2C, SPI or DSI for example) this is a good time
50 * to do that.
51 *
52 * After the display controller has started transmitting video data, it's safe
53 * to call the .enable() function. This will typically enable the backlight to
54 * make the image on screen visible. Some panels require a certain amount of
55 * time or frames before the image is displayed. This function is responsible
56 * for taking this into account before enabling the backlight to avoid visual
57 * glitches.
58 *
59 * Before stopping video transmission from the display controller it can be
60 * necessary to turn off the panel to avoid visual glitches. This is done in
61 * the .disable() function. Analogously to .enable() this typically involves
62 * turning off the backlight and waiting for some time to make sure no image
63 * is visible on the panel. It is then safe for the display controller to
64 * cease transmission of video data.
65 *
66 * To save power when no video data is transmitted, a driver can power down
67 * the panel. This is the job of the .unprepare() function.
68 *
69 * Backlight can be handled automatically if configured using
70 * drm_panel_of_backlight() or drm_panel_dp_aux_backlight(). Then the driver
71 * does not need to implement the functionality to enable/disable backlight.
72 */
73 struct drm_panel_funcs {
74 /**
75 * @prepare:
76 *
77 * Turn on panel and perform set up.
78 *
79 * This function is optional.
80 */
81 int (*prepare)(struct drm_panel *panel);
82
83 /**
84 * @enable:
85 *
86 * Enable panel (turn on back light, etc.).
87 *
88 * This function is optional.
89 */
90 int (*enable)(struct drm_panel *panel);
91
92 /**
93 * @disable:
94 *
95 * Disable panel (turn off back light, etc.).
96 *
97 * This function is optional.
98 */
99 int (*disable)(struct drm_panel *panel);
100
101 /**
102 * @unprepare:
103 *
104 * Turn off panel.
105 *
106 * This function is optional.
107 */
108 int (*unprepare)(struct drm_panel *panel);
109
110 /**
111 * @get_modes:
112 *
113 * Add modes to the connector that the panel is attached to
114 * and returns the number of modes added.
115 *
116 * This function is mandatory.
117 */
118 int (*get_modes)(struct drm_panel *panel,
119 struct drm_connector *connector);
120
121 /**
122 * @get_orientation:
123 *
124 * Return the panel orientation set by device tree or EDID.
125 *
126 * This function is optional.
127 */
128 enum drm_panel_orientation (*get_orientation)(struct drm_panel *panel);
129
130 /**
131 * @get_timings:
132 *
133 * Copy display timings into the provided array and return
134 * the number of display timings available.
135 *
136 * This function is optional.
137 */
138 int (*get_timings)(struct drm_panel *panel, unsigned int num_timings,
139 struct display_timing *timings);
140
141 /**
142 * @debugfs_init:
143 *
144 * Allows panels to create panels-specific debugfs files.
145 */
146 void (*debugfs_init)(struct drm_panel *panel, struct dentry *root);
147 };
148
149 struct drm_panel_follower_funcs {
150 /**
151 * @panel_prepared:
152 *
153 * Called after the panel has been powered on.
154 */
155 int (*panel_prepared)(struct drm_panel_follower *follower);
156
157 /**
158 * @panel_unpreparing:
159 *
160 * Called before the panel is powered off.
161 */
162 int (*panel_unpreparing)(struct drm_panel_follower *follower);
163 };
164
165 struct drm_panel_follower {
166 /**
167 * @funcs:
168 *
169 * Dependent device callbacks; should be initted by the caller.
170 */
171 const struct drm_panel_follower_funcs *funcs;
172
173 /**
174 * @list
175 *
176 * Used for linking into panel's list; set by drm_panel_add_follower().
177 */
178 struct list_head list;
179
180 /**
181 * @panel
182 *
183 * The panel we're dependent on; set by drm_panel_add_follower().
184 */
185 struct drm_panel *panel;
186 };
187
188 /**
189 * struct drm_panel - DRM panel object
190 */
191 struct drm_panel {
192 /**
193 * @dev:
194 *
195 * Parent device of the panel.
196 */
197 struct device *dev;
198
199 /**
200 * @backlight:
201 *
202 * Backlight device, used to turn on backlight after the call
203 * to enable(), and to turn off backlight before the call to
204 * disable().
205 * backlight is set by drm_panel_of_backlight() or
206 * drm_panel_dp_aux_backlight() and drivers shall not assign it.
207 */
208 struct backlight_device *backlight;
209
210 /**
211 * @funcs:
212 *
213 * Operations that can be performed on the panel.
214 */
215 const struct drm_panel_funcs *funcs;
216
217 /**
218 * @connector_type:
219 *
220 * Type of the panel as a DRM_MODE_CONNECTOR_* value. This is used to
221 * initialise the drm_connector corresponding to the panel with the
222 * correct connector type.
223 */
224 int connector_type;
225
226 /**
227 * @list:
228 *
229 * Panel entry in registry.
230 */
231 struct list_head list;
232
233 /**
234 * @followers:
235 *
236 * A list of struct drm_panel_follower dependent on this panel.
237 */
238 struct list_head followers;
239
240 /**
241 * @follower_lock:
242 *
243 * Lock for followers list.
244 */
245 struct mutex follower_lock;
246
247 /**
248 * @prepare_prev_first:
249 *
250 * The previous controller should be prepared first, before the prepare
251 * for the panel is called. This is largely required for DSI panels
252 * where the DSI host controller should be initialised to LP-11 before
253 * the panel is powered up.
254 */
255 bool prepare_prev_first;
256
257 /**
258 * @prepared:
259 *
260 * If true then the panel has been prepared.
261 */
262 bool prepared;
263
264 /**
265 * @enabled:
266 *
267 * If true then the panel has been enabled.
268 */
269 bool enabled;
270 };
271
272 void drm_panel_init(struct drm_panel *panel, struct device *dev,
273 const struct drm_panel_funcs *funcs,
274 int connector_type);
275
276 void drm_panel_add(struct drm_panel *panel);
277 void drm_panel_remove(struct drm_panel *panel);
278
279 int drm_panel_prepare(struct drm_panel *panel);
280 int drm_panel_unprepare(struct drm_panel *panel);
281
282 int drm_panel_enable(struct drm_panel *panel);
283 int drm_panel_disable(struct drm_panel *panel);
284
285 int drm_panel_get_modes(struct drm_panel *panel, struct drm_connector *connector);
286
287 #if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL)
288 struct drm_panel *of_drm_find_panel(const struct device_node *np);
289 int of_drm_get_panel_orientation(const struct device_node *np,
290 enum drm_panel_orientation *orientation);
291 #else
292 static inline struct drm_panel *of_drm_find_panel(const struct device_node *np)
293 {
294 return ERR_PTR(-ENODEV);
295 }
296
297 static inline int of_drm_get_panel_orientation(const struct device_node *np,
298 enum drm_panel_orientation *orientation)
299 {
300 return -ENODEV;
301 }
302 #endif
303
304 #if defined(CONFIG_DRM_PANEL)
305 bool drm_is_panel_follower(struct device *dev);
306 int drm_panel_add_follower(struct device *follower_dev,
307 struct drm_panel_follower *follower);
308 void drm_panel_remove_follower(struct drm_panel_follower *follower);
309 int devm_drm_panel_add_follower(struct device *follower_dev,
310 struct drm_panel_follower *follower);
311 #else
312 static inline bool drm_is_panel_follower(struct device *dev)
313 {
314 return false;
315 }
316
317 static inline int drm_panel_add_follower(struct device *follower_dev,
318 struct drm_panel_follower *follower)
319 {
320 return -ENODEV;
321 }
322
323 static inline void drm_panel_remove_follower(struct drm_panel_follower *follower) { }
324 static inline int devm_drm_panel_add_follower(struct device *follower_dev,
325 struct drm_panel_follower *follower)
326 {
327 return -ENODEV;
328 }
329 #endif
330
331 #if IS_ENABLED(CONFIG_DRM_PANEL) && (IS_BUILTIN(CONFIG_BACKLIGHT_CLASS_DEVICE) || \
332 (IS_MODULE(CONFIG_DRM) && IS_MODULE(CONFIG_BACKLIGHT_CLASS_DEVICE)))
333 int drm_panel_of_backlight(struct drm_panel *panel);
334 #else
335 static inline int drm_panel_of_backlight(struct drm_panel *panel)
336 {
337 return 0;
338 }
339 #endif
340
341 #endif
342
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