summaryrefslogtreecommitdiff
path: root/include/drm/drm_bridge.h
blob: 694e153a75314b4f3c550e4f30da0ceff1f3675d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
/*
 * Copyright (c) 2016 Intel Corporation
 *
 * Permission to use, copy, modify, distribute, and sell this software and its
 * documentation for any purpose is hereby granted without fee, provided that
 * the above copyright notice appear in all copies and that both that copyright
 * notice and this permission notice appear in supporting documentation, and
 * that the name of the copyright holders not be used in advertising or
 * publicity pertaining to distribution of the software without specific,
 * written prior permission.  The copyright holders make no representations
 * about the suitability of this software for any purpose.  It is provided "as
 * is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

#ifndef __DRM_BRIDGE_H__
#define __DRM_BRIDGE_H__

#include <linux/list.h>
#include <linux/ctype.h>
#include <drm/drm_encoder.h>
#include <drm/drm_mode_object.h>
#include <drm/drm_modes.h>

struct drm_bridge;
struct drm_bridge_timings;
struct drm_panel;

/**
 * struct drm_bridge_funcs - drm_bridge control functions
 */
struct drm_bridge_funcs {
	/**
	 * @attach:
	 *
	 * This callback is invoked whenever our bridge is being attached to a
	 * &drm_encoder.
	 *
	 * The @attach callback is optional.
	 *
	 * RETURNS:
	 *
	 * Zero on success, error code on failure.
	 */
	int (*attach)(struct drm_bridge *bridge);

	/**
	 * @detach:
	 *
	 * This callback is invoked whenever our bridge is being detached from a
	 * &drm_encoder.
	 *
	 * The @detach callback is optional.
	 */
	void (*detach)(struct drm_bridge *bridge);

	/**
	 * @mode_valid:
	 *
	 * This callback is used to check if a specific mode is valid in this
	 * bridge. This should be implemented if the bridge has some sort of
	 * restriction in the modes it can display. For example, a given bridge
	 * may be responsible to set a clock value. If the clock can not
	 * produce all the values for the available modes then this callback
	 * can be used to restrict the number of modes to only the ones that
	 * can be displayed.
	 *
	 * This hook is used by the probe helpers to filter the mode list in
	 * drm_helper_probe_single_connector_modes(), and it is used by the
	 * atomic helpers to validate modes supplied by userspace in
	 * drm_atomic_helper_check_modeset().
	 *
	 * The @mode_valid callback is optional.
	 *
	 * NOTE:
	 *
	 * Since this function is both called from the check phase of an atomic
	 * commit, and the mode validation in the probe paths it is not allowed
	 * to look at anything else but the passed-in mode, and validate it
	 * against configuration-invariant hardward constraints. Any further
	 * limits which depend upon the configuration can only be checked in
	 * @mode_fixup.
	 *
	 * RETURNS:
	 *
	 * drm_mode_status Enum
	 */
	enum drm_mode_status (*mode_valid)(struct drm_bridge *bridge,
					   const struct drm_display_mode *mode);

	/**
	 * @mode_fixup:
	 *
	 * This callback is used to validate and adjust a mode. The parameter
	 * mode is the display mode that should be fed to the next element in
	 * the display chain, either the final &drm_connector or the next
	 * &drm_bridge. The parameter adjusted_mode is the input mode the bridge
	 * requires. It can be modified by this callback and does not need to
	 * match mode. See also &drm_crtc_state.adjusted_mode for more details.
	 *
	 * This is the only hook that allows a bridge to reject a modeset. If
	 * this function passes all other callbacks must succeed for this
	 * configuration.
	 *
	 * The @mode_fixup callback is optional.
	 *
	 * NOTE:
	 *
	 * This function is called in the check phase of atomic modesets, which
	 * can be aborted for any reason (including on userspace's request to
	 * just check whether a configuration would be possible). Drivers MUST
	 * NOT touch any persistent state (hardware or software) or data
	 * structures except the passed in @state parameter.
	 *
	 * Also beware that userspace can request its own custom modes, neither
	 * core nor helpers filter modes to the list of probe modes reported by
	 * the GETCONNECTOR IOCTL and stored in &drm_connector.modes. To ensure
	 * that modes are filtered consistently put any bridge constraints and
	 * limits checks into @mode_valid.
	 *
	 * RETURNS:
	 *
	 * True if an acceptable configuration is possible, false if the modeset
	 * operation should be rejected.
	 */
	bool (*mode_fixup)(struct drm_bridge *bridge,
			   const struct drm_display_mode *mode,
			   struct drm_display_mode *adjusted_mode);
	/**
	 * @disable:
	 *
	 * This callback should disable the bridge. It is called right before
	 * the preceding element in the display pipe is disabled. If the
	 * preceding element is a bridge this means it's called before that
	 * bridge's @disable vfunc. If the preceding element is a &drm_encoder
	 * it's called right before the &drm_encoder_helper_funcs.disable,
	 * &drm_encoder_helper_funcs.prepare or &drm_encoder_helper_funcs.dpms
	 * hook.
	 *
	 * The bridge can assume that the display pipe (i.e. clocks and timing
	 * signals) feeding it is still running when this callback is called.
	 *
	 * The @disable callback is optional.
	 */
	void (*disable)(struct drm_bridge *bridge);

	/**
	 * @post_disable:
	 *
	 * This callback should disable the bridge. It is called right after the
	 * preceding element in the display pipe is disabled. If the preceding
	 * element is a bridge this means it's called after that bridge's
	 * @post_disable function. If the preceding element is a &drm_encoder
	 * it's called right after the encoder's
	 * &drm_encoder_helper_funcs.disable, &drm_encoder_helper_funcs.prepare
	 * or &drm_encoder_helper_funcs.dpms hook.
	 *
	 * The bridge must assume that the display pipe (i.e. clocks and timing
	 * singals) feeding it is no longer running when this callback is
	 * called.
	 *
	 * The @post_disable callback is optional.
	 */
	void (*post_disable)(struct drm_bridge *bridge);

	/**
	 * @mode_set:
	 *
	 * This callback should set the given mode on the bridge. It is called
	 * after the @mode_set callback for the preceding element in the display
	 * pipeline has been called already. If the bridge is the first element
	 * then this would be &drm_encoder_helper_funcs.mode_set. The display
	 * pipe (i.e.  clocks and timing signals) is off when this function is
	 * called.
	 *
	 * The adjusted_mode parameter is the mode output by the CRTC for the
	 * first bridge in the chain. It can be different from the mode
	 * parameter that contains the desired mode for the connector at the end
	 * of the bridges chain, for instance when the first bridge in the chain
	 * performs scaling. The adjusted mode is mostly useful for the first
	 * bridge in the chain and is likely irrelevant for the other bridges.
	 *
	 * For atomic drivers the adjusted_mode is the mode stored in
	 * &drm_crtc_state.adjusted_mode.
	 *
	 * NOTE:
	 *
	 * If a need arises to store and access modes adjusted for other
	 * locations than the connection between the CRTC and the first bridge,
	 * the DRM framework will have to be extended with DRM bridge states.
	 */
	void (*mode_set)(struct drm_bridge *bridge,
			 const struct drm_display_mode *mode,
			 const struct drm_display_mode *adjusted_mode);
	/**
	 * @pre_enable:
	 *
	 * This callback should enable the bridge. It is called right before
	 * the preceding element in the display pipe is enabled. If the
	 * preceding element is a bridge this means it's called before that
	 * bridge's @pre_enable function. If the preceding element is a
	 * &drm_encoder it's called right before the encoder's
	 * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
	 * &drm_encoder_helper_funcs.dpms hook.
	 *
	 * The display pipe (i.e. clocks and timing signals) feeding this bridge
	 * will not yet be running when this callback is called. The bridge must
	 * not enable the display link feeding the next bridge in the chain (if
	 * there is one) when this callback is called.
	 *
	 * The @pre_enable callback is optional.
	 */
	void (*pre_enable)(struct drm_bridge *bridge);

	/**
	 * @enable:
	 *
	 * This callback should enable the bridge. It is called right after
	 * the preceding element in the display pipe is enabled. If the
	 * preceding element is a bridge this means it's called after that
	 * bridge's @enable function. If the preceding element is a
	 * &drm_encoder it's called right after the encoder's
	 * &drm_encoder_helper_funcs.enable, &drm_encoder_helper_funcs.commit or
	 * &drm_encoder_helper_funcs.dpms hook.
	 *
	 * The bridge can assume that the display pipe (i.e. clocks and timing
	 * signals) feeding it is running when this callback is called. This
	 * callback must enable the display link feeding the next bridge in the
	 * chain if there is one.
	 *
	 * The @enable callback is optional.
	 */
	void (*enable)(struct drm_bridge *bridge);

	/**
	 * @atomic_pre_enable:
	 *
	 * This callback should enable the bridge. It is called right before
	 * the preceding element in the display pipe is enabled. If the
	 * preceding element is a bridge this means it's called before that
	 * bridge's @atomic_pre_enable or @pre_enable function. If the preceding
	 * element is a &drm_encoder it's called right before the encoder's
	 * &drm_encoder_helper_funcs.atomic_enable hook.
	 *
	 * The display pipe (i.e. clocks and timing signals) feeding this bridge
	 * will not yet be running when this callback is called. The bridge must
	 * not enable the display link feeding the next bridge in the chain (if
	 * there is one) when this callback is called.
	 *
	 * Note that this function will only be invoked in the context of an
	 * atomic commit. It will not be invoked from
	 * &drm_bridge_chain_pre_enable. It would be prudent to also provide an
	 * implementation of @pre_enable if you are expecting driver calls into
	 * &drm_bridge_chain_pre_enable.
	 *
	 * The @atomic_pre_enable callback is optional.
	 */
	void (*atomic_pre_enable)(struct drm_bridge *bridge,
				  struct drm_atomic_state *old_state);

	/**
	 * @atomic_enable:
	 *
	 * This callback should enable the bridge. It is called right after
	 * the preceding element in the display pipe is enabled. If the
	 * preceding element is a bridge this means it's called after that
	 * bridge's @atomic_enable or @enable function. If the preceding element
	 * is a &drm_encoder it's called right after the encoder's
	 * &drm_encoder_helper_funcs.atomic_enable hook.
	 *
	 * The bridge can assume that the display pipe (i.e. clocks and timing
	 * signals) feeding it is running when this callback is called. This
	 * callback must enable the display link feeding the next bridge in the
	 * chain if there is one.
	 *
	 * Note that this function will only be invoked in the context of an
	 * atomic commit. It will not be invoked from &drm_bridge_chain_enable.
	 * It would be prudent to also provide an implementation of @enable if
	 * you are expecting driver calls into &drm_bridge_chain_enable.
	 *
	 * The @atomic_enable callback is optional.
	 */
	void (*atomic_enable)(struct drm_bridge *bridge,
			      struct drm_atomic_state *old_state);
	/**
	 * @atomic_disable:
	 *
	 * This callback should disable the bridge. It is called right before
	 * the preceding element in the display pipe is disabled. If the
	 * preceding element is a bridge this means it's called before that
	 * bridge's @atomic_disable or @disable vfunc. If the preceding element
	 * is a &drm_encoder it's called right before the
	 * &drm_encoder_helper_funcs.atomic_disable hook.
	 *
	 * The bridge can assume that the display pipe (i.e. clocks and timing
	 * signals) feeding it is still running when this callback is called.
	 *
	 * Note that this function will only be invoked in the context of an
	 * atomic commit. It will not be invoked from
	 * &drm_bridge_chain_disable. It would be prudent to also provide an
	 * implementation of @disable if you are expecting driver calls into
	 * &drm_bridge_chain_disable.
	 *
	 * The @atomic_disable callback is optional.
	 */
	void (*atomic_disable)(struct drm_bridge *bridge,
			       struct drm_atomic_state *old_state);

	/**
	 * @atomic_post_disable:
	 *
	 * This callback should disable the bridge. It is called right after the
	 * preceding element in the display pipe is disabled. If the preceding
	 * element is a bridge this means it's called after that bridge's
	 * @atomic_post_disable or @post_disable function. If the preceding
	 * element is a &drm_encoder it's called right after the encoder's
	 * &drm_encoder_helper_funcs.atomic_disable hook.
	 *
	 * The bridge must assume that the display pipe (i.e. clocks and timing
	 * signals) feeding it is no longer running when this callback is
	 * called.
	 *
	 * Note that this function will only be invoked in the context of an
	 * atomic commit. It will not be invoked from
	 * &drm_bridge_chain_post_disable.
	 * It would be prudent to also provide an implementation of
	 * @post_disable if you are expecting driver calls into
	 * &drm_bridge_chain_post_disable.
	 *
	 * The @atomic_post_disable callback is optional.
	 */
	void (*atomic_post_disable)(struct drm_bridge *bridge,
				    struct drm_atomic_state *old_state);
};

/**
 * struct drm_bridge_timings - timing information for the bridge
 */
struct drm_bridge_timings {
	/**
	 * @input_bus_flags:
	 *
	 * Tells what additional settings for the pixel data on the bus
	 * this bridge requires (like pixel signal polarity). See also
	 * &drm_display_info->bus_flags.
	 */
	u32 input_bus_flags;
	/**
	 * @setup_time_ps:
	 *
	 * Defines the time in picoseconds the input data lines must be
	 * stable before the clock edge.
	 */
	u32 setup_time_ps;
	/**
	 * @hold_time_ps:
	 *
	 * Defines the time in picoseconds taken for the bridge to sample the
	 * input signal after the clock edge.
	 */
	u32 hold_time_ps;
	/**
	 * @dual_link:
	 *
	 * True if the bus operates in dual-link mode. The exact meaning is
	 * dependent on the bus type. For LVDS buses, this indicates that even-
	 * and odd-numbered pixels are received on separate links.
	 */
	bool dual_link;
};

/**
 * struct drm_bridge - central DRM bridge control structure
 */
struct drm_bridge {
	/** @dev: DRM device this bridge belongs to */
	struct drm_device *dev;
	/** @encoder: encoder to which this bridge is connected */
	struct drm_encoder *encoder;
	/** @chain_node: used to form a bridge chain */
	struct list_head chain_node;
#ifdef CONFIG_OF
	/** @of_node: device node pointer to the bridge */
	struct device_node *of_node;
#endif
	/** @list: to keep track of all added bridges */
	struct list_head list;
	/**
	 * @timings:
	 *
	 * the timing specification for the bridge, if any (may be NULL)
	 */
	const struct drm_bridge_timings *timings;
	/** @funcs: control functions */
	const struct drm_bridge_funcs *funcs;
	/** @driver_private: pointer to the bridge driver's internal context */
	void *driver_private;
};

void drm_bridge_add(struct drm_bridge *bridge);
void drm_bridge_remove(struct drm_bridge *bridge);
struct drm_bridge *of_drm_find_bridge(struct device_node *np);
int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
		      struct drm_bridge *previous);

/**
 * drm_bridge_get_next_bridge() - Get the next bridge in the chain
 * @bridge: bridge object
 *
 * RETURNS:
 * the next bridge in the chain after @bridge, or NULL if @bridge is the last.
 */
static inline struct drm_bridge *
drm_bridge_get_next_bridge(struct drm_bridge *bridge)
{
	if (list_is_last(&bridge->chain_node, &bridge->encoder->bridge_chain))
		return NULL;

	return list_next_entry(bridge, chain_node);
}

/**
 * drm_bridge_get_prev_bridge() - Get the previous bridge in the chain
 * @bridge: bridge object
 *
 * RETURNS:
 * the previous bridge in the chain, or NULL if @bridge is the first.
 */
static inline struct drm_bridge *
drm_bridge_get_prev_bridge(struct drm_bridge *bridge)
{
	if (list_is_first(&bridge->chain_node, &bridge->encoder->bridge_chain))
		return NULL;

	return list_prev_entry(bridge, chain_node);
}

/**
 * drm_bridge_chain_get_first_bridge() - Get the first bridge in the chain
 * @encoder: encoder object
 *
 * RETURNS:
 * the first bridge in the chain, or NULL if @encoder has no bridge attached
 * to it.
 */
static inline struct drm_bridge *
drm_bridge_chain_get_first_bridge(struct drm_encoder *encoder)
{
	return list_first_entry_or_null(&encoder->bridge_chain,
					struct drm_bridge, chain_node);
}

/**
 * drm_for_each_bridge_in_chain() - Iterate over all bridges present in a chain
 * @encoder: the encoder to iterate bridges on
 * @bridge: a bridge pointer updated to point to the current bridge at each
 *	    iteration
 *
 * Iterate over all bridges present in the bridge chain attached to @encoder.
 */
#define drm_for_each_bridge_in_chain(encoder, bridge)			\
	list_for_each_entry(bridge, &(encoder)->bridge_chain, chain_node)

bool drm_bridge_chain_mode_fixup(struct drm_bridge *bridge,
				 const struct drm_display_mode *mode,
				 struct drm_display_mode *adjusted_mode);
enum drm_mode_status
drm_bridge_chain_mode_valid(struct drm_bridge *bridge,
			    const struct drm_display_mode *mode);
void drm_bridge_chain_disable(struct drm_bridge *bridge);
void drm_bridge_chain_post_disable(struct drm_bridge *bridge);
void drm_bridge_chain_mode_set(struct drm_bridge *bridge,
			       const struct drm_display_mode *mode,
			       const struct drm_display_mode *adjusted_mode);
void drm_bridge_chain_pre_enable(struct drm_bridge *bridge);
void drm_bridge_chain_enable(struct drm_bridge *bridge);

void drm_atomic_bridge_chain_disable(struct drm_bridge *bridge,
				     struct drm_atomic_state *state);
void drm_atomic_bridge_chain_post_disable(struct drm_bridge *bridge,
					  struct drm_atomic_state *state);
void drm_atomic_bridge_chain_pre_enable(struct drm_bridge *bridge,
					struct drm_atomic_state *state);
void drm_atomic_bridge_chain_enable(struct drm_bridge *bridge,
				    struct drm_atomic_state *state);

#ifdef CONFIG_DRM_PANEL_BRIDGE
struct drm_bridge *drm_panel_bridge_add(struct drm_panel *panel);
struct drm_bridge *drm_panel_bridge_add_typed(struct drm_panel *panel,
					      u32 connector_type);
void drm_panel_bridge_remove(struct drm_bridge *bridge);
struct drm_bridge *devm_drm_panel_bridge_add(struct device *dev,
					     struct drm_panel *panel);
struct drm_bridge *devm_drm_panel_bridge_add_typed(struct device *dev,
						   struct drm_panel *panel,
						   u32 connector_type);
struct drm_connector *drm_panel_bridge_connector(struct drm_bridge *bridge);
#endif

#endif