1 /*
2 * Copyright (c) 2016 Intel Corporation
3 *
4 * Permission to use, copy, modify, distribute, and sell this software and its
5 * documentation for any purpose is hereby granted without fee, provided that
6 * the above copyright notice appear in all copies and that both that copyright
7 * notice and this permission notice appear in supporting documentation, and
8 * that the name of the copyright holders not be used in advertising or
9 * publicity pertaining to distribution of the software without specific,
10 * written prior permission. The copyright holders make no representations
11 * about the suitability of this software for any purpose. It is provided "as
12 * is" without express or implied warranty.
13 *
14 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
15 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
16 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
17 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
18 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
19 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
20 * OF THIS SOFTWARE.
21 */
22
23 #ifndef __DRM_BRIDGE_H__
24 #define __DRM_BRIDGE_H__
25
26 #include <linux/list.h>
27 #include <linux/ctype.h>
28 #include <drm/drm_mode_object.h>
29 #include <drm/drm_modes.h>
30
31 struct drm_bridge;
32 struct drm_bridge_timings;
33 struct drm_panel;
34
35 /**
36 * struct drm_bridge_funcs - drm_bridge control functions
37 */
38 struct drm_bridge_funcs {
39 /**
40 * @attach:
41 *
42 * This callback is invoked whenever our bridge is being attached to a
43 * &drm_encoder.
44 *
45 * The attach callback is optional.
46 *
47 * RETURNS:
48 *
49 * Zero on success, error code on failure.
50 */
51 int (*attach)(struct drm_bridge *bridge);
52
53 /**
54 * @detach:
55 *
56 * This callback is invoked whenever our bridge is being detached from a
57 * &drm_encoder.
58 *
59 * The detach callback is optional.
60 */
61 void (*detach)(struct drm_bridge *bridge);
62
63 /**
64 * @mode_valid:
65 *
66 * This callback is used to check if a specific mode is valid in this
67 * bridge. This should be implemented if the bridge has some sort of
68 * restriction in the modes it can display. For example, a given bridge
69 * may be responsible to set a clock value. If the clock can not
70 * produce all the values for the available modes then this callback
71 * can be used to restrict the number of modes to only the ones that
72 * can be displayed.
73 *
74 * This hook is used by the probe helpers to filter the mode list in
75 * drm_helper_probe_single_connector_modes(), and it is used by the
76 * atomic helpers to validate modes supplied by userspace in
77 * drm_atomic_helper_check_modeset().
78 *
79 * This function is optional.
80 *
81 * NOTE:
82 *
83 * Since this function is both called from the check phase of an atomic
84 * commit, and the mode validation in the probe paths it is not allowed
85 * to look at anything else but the passed-in mode, and validate it
86 * against configuration-invariant hardward constraints. Any further
87 * limits which depend upon the configuration can only be checked in
88 * @mode_fixup.
89 *
90 * RETURNS:
91 *
92 * drm_mode_status Enum
93 */
94 enum drm_mode_status (*mode_valid)(struct drm_bridge *bridge,
95 const struct drm_display_mode *mode);
96
97 /**
98 * @mode_fixup:
99 *
100 * This callback is used to validate and adjust a mode. The parameter
101 * mode is the display mode that should be fed to the next element in
102 * the display chain, either the final &drm_connector or the next
103 * &drm_bridge. The parameter adjusted_mode is the input mode the bridge
104 * requires. It can be modified by this callback and does not need to
105 * match mode. See also &drm_crtc_state.adjusted_mode for more details.
106 *
107 * This is the only hook that allows a bridge to reject a modeset. If
108 * this function passes all other callbacks must succeed for this
109 * configuration.
110 *
111 * The mode_fixup callback is optional.
112 *
113 * NOTE:
114 *
115 * This function is called in the check phase of atomic modesets, which
116 * can be aborted for any reason (including on userspace's request to
117 * just check whether a configuration would be possible). Drivers MUST
118 * NOT touch any persistent state (hardware or software) or data
119 * structures except the passed in @state parameter.
120 *
121 * Also beware that userspace can request its own custom modes, neither
122 * core nor helpers filter modes to the list of probe modes reported by
123 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
124 * that modes are filtered consistently put any bridge constraints and
125 * limits checks into @mode_valid.
126 *
127 * RETURNS:
128 *
129 * True if an acceptable configuration is possible, false if the modeset
130 * operation should be rejected.
131 */
132 bool (*mode_fixup)(struct drm_bridge *bridge,
133 const struct drm_display_mode *mode,
134 struct drm_display_mode *adjusted_mode);
135 /**
136 * @disable:
137 *
138 * This callback should disable the bridge. It is called right before
139 * the preceding element in the display pipe is disabled. If the
140 * preceding element is a bridge this means it's called before that
141 * bridge's @disable vfunc. If the preceding element is a &drm_encoder
142 * it's called right before the &drm_encoder_helper_funcs.disable,
143 * &drm_encoder_helper_funcs.prepare or &drm_encoder_helper_funcs.dpms
144 * hook.
145 *
146 * The bridge can assume that the display pipe (i.e. clocks and timing
147 * signals) feeding it is still running when this callback is called.
148 *
149 * The disable callback is optional.
150 */
151 void (*disable)(struct drm_bridge *bridge);
152
153 /**
154 * @post_disable:
155 *
156 * This callback should disable the bridge. It is called right after the
157 * preceding element in the display pipe is disabled. If the preceding
158 * element is a bridge this means it's called after that bridge's
159 * @post_disable function. If the preceding element is a &drm_encoder
160 * it's called right after the encoder's
161 * &drm_encoder_helper_funcs.disable, &drm_encoder_helper_funcs.prepare
162 * or &drm_encoder_helper_funcs.dpms hook.
163 *
164 * The bridge must assume that the display pipe (i.e. clocks and timing
165 * singals) feeding it is no longer running when this callback is
166 * called.
167 *
168 * The post_disable callback is optional.
169 */
170 void (*post_disable)(struct drm_bridge *bridge);
171
172 /**
173 * @mode_set:
174 *
175 * This callback should set the given mode on the bridge. It is called
176 * after the @mode_set callback for the preceding element in the display
177 * pipeline has been called already. If the bridge is the first element
178 * then this would be &drm_encoder_helper_funcs.mode_set. The display
179 * pipe (i.e. clocks and timing signals) is off when this function is
180 * called.
181 *
182 * The adjusted_mode parameter is the mode output by the CRTC for the
183 * first bridge in the chain. It can be different from the mode
184 * parameter that contains the desired mode for the connector at the end
185 * of the bridges chain, for instance when the first bridge in the chain
186 * performs scaling. The adjusted mode is mostly useful for the first
187 * bridge in the chain and is likely irrelevant for the other bridges.
188 *
189 * For atomic drivers the adjusted_mode is the mode stored in
190 * &drm_crtc_state.adjusted_mode.
191 *
192 * NOTE:
193 *
194 * If a need arises to store and access modes adjusted for other
195 * locations than the connection between the CRTC and the first bridge,
196 * the DRM framework will have to be extended with DRM bridge states.
197 */
198 void (*mode_set)(struct drm_bridge *bridge,
199 const struct drm_display_mode *mode,
200 const struct drm_display_mode *adjusted_mode);
201 /**
202 * @pre_enable:
203 *
204 * This callback should enable the bridge. It is called right before
205 * the preceding element in the display pipe is enabled. If the
206 * preceding element is a bridge this means it's called before that
207 * bridge's @pre_enable function. If the preceding element is a
208 * &drm_encoder it's called right before the encoder's
209 * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
210 * &drm_encoder_helper_funcs.dpms hook.
211 *
212 * The display pipe (i.e. clocks and timing signals) feeding this bridge
213 * will not yet be running when this callback is called. The bridge must
214 * not enable the display link feeding the next bridge in the chain (if
215 * there is one) when this callback is called.
216 *
217 * The pre_enable callback is optional.
218 */
219 void (*pre_enable)(struct drm_bridge *bridge);
220
221 /**
222 * @enable:
223 *
224 * This callback should enable the bridge. It is called right after
225 * the preceding element in the display pipe is enabled. If the
226 * preceding element is a bridge this means it's called after that
227 * bridge's @enable function. If the preceding element is a
228 * &drm_encoder it's called right after the encoder's
229 * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
230 * &drm_encoder_helper_funcs.dpms hook.
231 *
232 * The bridge can assume that the display pipe (i.e. clocks and timing
233 * signals) feeding it is running when this callback is called. This
234 * callback must enable the display link feeding the next bridge in the
235 * chain if there is one.
236 *
237 * The enable callback is optional.
238 */
239 void (*enable)(struct drm_bridge *bridge);
240
241 /**
242 * @atomic_pre_enable:
243 *
244 * This callback should enable the bridge. It is called right before
245 * the preceding element in the display pipe is enabled. If the
246 * preceding element is a bridge this means it's called before that
247 * bridge's @atomic_pre_enable or @pre_enable function. If the preceding
248 * element is a &drm_encoder it's called right before the encoder's
249 * &drm_encoder_helper_funcs.atomic_enable hook.
250 *
251 * The display pipe (i.e. clocks and timing signals) feeding this bridge
252 * will not yet be running when this callback is called. The bridge must
253 * not enable the display link feeding the next bridge in the chain (if
254 * there is one) when this callback is called.
255 *
256 * Note that this function will only be invoked in the context of an
257 * atomic commit. It will not be invoked from &drm_bridge_pre_enable. It
258 * would be prudent to also provide an implementation of @pre_enable if
259 * you are expecting driver calls into &drm_bridge_pre_enable.
260 *
261 * The @atomic_pre_enable callback is optional.
262 */
263 void (*atomic_pre_enable)(struct drm_bridge *bridge,
264 struct drm_atomic_state *state);
265
266 /**
267 * @atomic_enable:
268 *
269 * This callback should enable the bridge. It is called right after
270 * the preceding element in the display pipe is enabled. If the
271 * preceding element is a bridge this means it's called after that
272 * bridge's @atomic_enable or @enable function. If the preceding element
273 * is a &drm_encoder it's called right after the encoder's
274 * &drm_encoder_helper_funcs.atomic_enable hook.
275 *
276 * The bridge can assume that the display pipe (i.e. clocks and timing
277 * signals) feeding it is running when this callback is called. This
278 * callback must enable the display link feeding the next bridge in the
279 * chain if there is one.
280 *
281 * Note that this function will only be invoked in the context of an
282 * atomic commit. It will not be invoked from &drm_bridge_enable. It
283 * would be prudent to also provide an implementation of @enable if
284 * you are expecting driver calls into &drm_bridge_enable.
285 *
286 * The enable callback is optional.
287 */
288 void (*atomic_enable)(struct drm_bridge *bridge,
289 struct drm_atomic_state *state);
290 /**
291 * @atomic_disable:
292 *
293 * This callback should disable the bridge. It is called right before
294 * the preceding element in the display pipe is disabled. If the
295 * preceding element is a bridge this means it's called before that
296 * bridge's @atomic_disable or @disable vfunc. If the preceding element
297 * is a &drm_encoder it's called right before the
298 * &drm_encoder_helper_funcs.atomic_disable hook.
299 *
300 * The bridge can assume that the display pipe (i.e. clocks and timing
301 * signals) feeding it is still running when this callback is called.
302 *
303 * Note that this function will only be invoked in the context of an
304 * atomic commit. It will not be invoked from &drm_bridge_disable. It
305 * would be prudent to also provide an implementation of @disable if
306 * you are expecting driver calls into &drm_bridge_disable.
307 *
308 * The disable callback is optional.
309 */
310 void (*atomic_disable)(struct drm_bridge *bridge,
311 struct drm_atomic_state *state);
312
313 /**
314 * @atomic_post_disable:
315 *
316 * This callback should disable the bridge. It is called right after the
317 * preceding element in the display pipe is disabled. If the preceding
318 * element is a bridge this means it's called after that bridge's
319 * @atomic_post_disable or @post_disable function. If the preceding
320 * element is a &drm_encoder it's called right after the encoder's
321 * &drm_encoder_helper_funcs.atomic_disable hook.
322 *
323 * The bridge must assume that the display pipe (i.e. clocks and timing
324 * signals) feeding it is no longer running when this callback is
325 * called.
326 *
327 * Note that this function will only be invoked in the context of an
328 * atomic commit. It will not be invoked from &drm_bridge_post_disable.
329 * It would be prudent to also provide an implementation of
330 * @post_disable if you are expecting driver calls into
331 * &drm_bridge_post_disable.
332 *
333 * The post_disable callback is optional.
334 */
335 void (*atomic_post_disable)(struct drm_bridge *bridge,
336 struct drm_atomic_state *state);
337 };
338
339 /**
340 * struct drm_bridge_timings - timing information for the bridge
341 */
342 struct drm_bridge_timings {
343 /**
344 * @input_bus_flags:
345 *
346 * Tells what additional settings for the pixel data on the bus
347 * this bridge requires (like pixel signal polarity). See also
348 * &drm_display_info->bus_flags.
349 */
350 u32 input_bus_flags;
351 /**
352 * @setup_time_ps:
353 *
354 * Defines the time in picoseconds the input data lines must be
355 * stable before the clock edge.
356 */
357 u32 setup_time_ps;
358 /**
359 * @hold_time_ps:
360 *
361 * Defines the time in picoseconds taken for the bridge to sample the
362 * input signal after the clock edge.
363 */
364 u32 hold_time_ps;
365 /**
366 * @dual_link:
367 *
368 * True if the bus operates in dual-link mode. The exact meaning is
369 * dependent on the bus type. For LVDS buses, this indicates that even-
370 * and odd-numbered pixels are received on separate links.
371 */
372 bool dual_link;
373 };
374
375 /**
376 * struct drm_bridge - central DRM bridge control structure
377 */
378 struct drm_bridge {
379 /** @dev: DRM device this bridge belongs to */
380 struct drm_device *dev;
381 /** @encoder: encoder to which this bridge is connected */
382 struct drm_encoder *encoder;
383 /** @next: the next bridge in the encoder chain */
384 struct drm_bridge *next;
385 #ifdef CONFIG_OF
386 /** @of_node: device node pointer to the bridge */
387 struct device_node *of_node;
388 #endif
389 /** @list: to keep track of all added bridges */
390 struct list_head list;
391 /**
392 * @timings:
393 *
394 * the timing specification for the bridge, if any (may be NULL)
395 */
396 const struct drm_bridge_timings *timings;
397 /** @funcs: control functions */
398 const struct drm_bridge_funcs *funcs;
399 /** @driver_private: pointer to the bridge driver's internal context */
400 void *driver_private;
401 };
402
403 void drm_bridge_add(struct drm_bridge *bridge);
404 void drm_bridge_remove(struct drm_bridge *bridge);
405 struct drm_bridge *of_drm_find_bridge(struct device_node *np);
406 int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
407 struct drm_bridge *previous);
408
409 bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
410 const struct drm_display_mode *mode,
411 struct drm_display_mode *adjusted_mode);
412 enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
413 const struct drm_display_mode *mode);
414 void drm_bridge_disable(struct drm_bridge *bridge);
415 void drm_bridge_post_disable(struct drm_bridge *bridge);
416 void drm_bridge_mode_set(struct drm_bridge *bridge,
417 const struct drm_display_mode *mode,
418 const struct drm_display_mode *adjusted_mode);
419 void drm_bridge_pre_enable(struct drm_bridge *bridge);
420 void drm_bridge_enable(struct drm_bridge *bridge);
421
422 void drm_atomic_bridge_disable(struct drm_bridge *bridge,
423 struct drm_atomic_state *state);
424 void drm_atomic_bridge_post_disable(struct drm_bridge *bridge,
425 struct drm_atomic_state *state);
426 void drm_atomic_bridge_pre_enable(struct drm_bridge *bridge,
427 struct drm_atomic_state *state);
428 void drm_atomic_bridge_enable(struct drm_bridge *bridge,
429 struct drm_atomic_state *state);
430
431 #ifdef CONFIG_DRM_PANEL_BRIDGE
432 struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel,
433 u32 connector_type);
434 void drm_panel_bridge_remove(struct drm_bridge *bridge);
435 struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
436 struct drm_panel *panel,
437 u32 connector_type);
438 #endif
439
440 #endif