1 /*
2 * Copyright (c) 2014 Samsung Electronics Co., Ltd
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 #include <linux/err.h>
25 #include <linux/module.h>
26 #include <linux/mutex.h>
27
28 #include <drm/drm_bridge.h>
29 #include <drm/drm_encoder.h>
30
31 #include "drm_crtc_internal.h"
32
33 /**
34 * DOC: overview
35 *
36 * &struct drm_bridge represents a device that hangs on to an encoder. These are
37 * handy when a regular &drm_encoder entity isn't enough to represent the entire
38 * encoder chain.
39 *
40 * A bridge is always attached to a single &drm_encoder at a time, but can be
41 * either connected to it directly, or through an intermediate bridge::
42 *
43 * encoder ---> bridge B ---> bridge A
44 *
45 * Here, the output of the encoder feeds to bridge B, and that furthers feeds to
46 * bridge A.
47 *
48 * The driver using the bridge is responsible to make the associations between
49 * the encoder and bridges. Once these links are made, the bridges will
50 * participate along with encoder functions to perform mode_set/enable/disable
51 * through the ops provided in &drm_bridge_funcs.
52 *
53 * drm_bridge, like drm_panel, aren't drm_mode_object entities like planes,
54 * CRTCs, encoders or connectors and hence are not visible to userspace. They
55 * just provide additional hooks to get the desired output at the end of the
56 * encoder chain.
57 *
58 * Bridges can also be chained up using the &drm_bridge.next pointer.
59 *
60 * Both legacy CRTC helpers and the new atomic modeset helpers support bridges.
61 */
62
63 static DEFINE_MUTEX(bridge_lock);
64 static LIST_HEAD(bridge_list);
65
66 /**
67 * drm_bridge_add - add the given bridge to the global bridge list
68 *
69 * @bridge: bridge control structure
70 */
71 void drm_bridge_add(struct drm_bridge *bridge)
72 {
73 mutex_lock(&bridge_lock);
74 list_add_tail(&bridge->list, &bridge_list);
75 mutex_unlock(&bridge_lock);
76 }
77 EXPORT_SYMBOL(drm_bridge_add);
78
79 /**
80 * drm_bridge_remove - remove the given bridge from the global bridge list
81 *
82 * @bridge: bridge control structure
83 */
84 void drm_bridge_remove(struct drm_bridge *bridge)
85 {
86 mutex_lock(&bridge_lock);
87 list_del_init(&bridge->list);
88 mutex_unlock(&bridge_lock);
89 }
90 EXPORT_SYMBOL(drm_bridge_remove);
91
92 /**
93 * drm_bridge_attach - attach the bridge to an encoder's chain
94 *
95 * @encoder: DRM encoder
96 * @bridge: bridge to attach
97 * @previous: previous bridge in the chain (optional)
98 *
99 * Called by a kms driver to link the bridge to an encoder's chain. The previous
100 * argument specifies the previous bridge in the chain. If NULL, the bridge is
101 * linked directly at the encoder's output. Otherwise it is linked at the
102 * previous bridge's output.
103 *
104 * If non-NULL the previous bridge must be already attached by a call to this
105 * function.
106 *
107 * Note that bridges attached to encoders are auto-detached during encoder
108 * cleanup in drm_encoder_cleanup(), so drm_bridge_attach() should generally
109 * *not* be balanced with a drm_bridge_detach() in driver code.
110 *
111 * RETURNS:
112 * Zero on success, error code on failure
113 */
114 int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
115 struct drm_bridge *previous)
116 {
117 int ret;
118
119 if (!encoder || !bridge)
120 return -EINVAL;
121
122 if (previous && (!previous->dev || previous->encoder != encoder))
123 return -EINVAL;
124
125 if (bridge->dev)
126 return -EBUSY;
127
128 bridge->dev = encoder->dev;
129 bridge->encoder = encoder;
130
131 if (bridge->funcs->attach) {
132 ret = bridge->funcs->attach(bridge);
133 if (ret < 0) {
134 bridge->dev = NULL;
135 bridge->encoder = NULL;
136 return ret;
137 }
138 }
139
140 if (previous)
141 previous->next = bridge;
142 else
143 encoder->bridge = bridge;
144
145 return 0;
146 }
147 EXPORT_SYMBOL(drm_bridge_attach);
148
149 void drm_bridge_detach(struct drm_bridge *bridge)
150 {
151 if (WARN_ON(!bridge))
152 return;
153
154 if (WARN_ON(!bridge->dev))
155 return;
156
157 if (bridge->funcs->detach)
158 bridge->funcs->detach(bridge);
159
160 bridge->dev = NULL;
161 }
162
163 /**
164 * DOC: bridge callbacks
165 *
166 * The &drm_bridge_funcs ops are populated by the bridge driver. The DRM
167 * internals (atomic and CRTC helpers) use the helpers defined in drm_bridge.c
168 * These helpers call a specific &drm_bridge_funcs op for all the bridges
169 * during encoder configuration.
170 *
171 * For detailed specification of the bridge callbacks see &drm_bridge_funcs.
172 */
173
174 /**
175 * drm_bridge_mode_fixup - fixup proposed mode for all bridges in the
176 * encoder chain
177 * @bridge: bridge control structure
178 * @mode: desired mode to be set for the bridge
179 * @adjusted_mode: updated mode that works for this bridge
180 *
181 * Calls &drm_bridge_funcs.mode_fixup for all the bridges in the
182 * encoder chain, starting from the first bridge to the last.
183 *
184 * Note: the bridge passed should be the one closest to the encoder
185 *
186 * RETURNS:
187 * true on success, false on failure
188 */
189 bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
190 const struct drm_display_mode *mode,
191 struct drm_display_mode *adjusted_mode)
192 {
193 bool ret = true;
194
195 if (!bridge)
196 return true;
197
198 if (bridge->funcs->mode_fixup)
199 ret = bridge->funcs->mode_fixup(bridge, mode, adjusted_mode);
200
201 ret = ret && drm_bridge_mode_fixup(bridge->next, mode, adjusted_mode);
202
203 return ret;
204 }
205 EXPORT_SYMBOL(drm_bridge_mode_fixup);
206
207 /**
208 * drm_bridge_mode_valid - validate the mode against all bridges in the
209 * encoder chain.
210 * @bridge: bridge control structure
211 * @mode: desired mode to be validated
212 *
213 * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
214 * chain, starting from the first bridge to the last. If at least one bridge
215 * does not accept the mode the function returns the error code.
216 *
217 * Note: the bridge passed should be the one closest to the encoder.
218 *
219 * RETURNS:
220 * MODE_OK on success, drm_mode_status Enum error code on failure
221 */
222 enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
223 const struct drm_display_mode *mode)
224 {
225 enum drm_mode_status ret = MODE_OK;
226
227 if (!bridge)
228 return ret;
229
230 if (bridge->funcs->mode_valid)
231 ret = bridge->funcs->mode_valid(bridge, mode);
232
233 if (ret != MODE_OK)
234 return ret;
235
236 return drm_bridge_mode_valid(bridge->next, mode);
237 }
238 EXPORT_SYMBOL(drm_bridge_mode_valid);
239
240 /**
241 * drm_bridge_disable - disables all bridges in the encoder chain
242 * @bridge: bridge control structure
243 *
244 * Calls &drm_bridge_funcs.disable op for all the bridges in the encoder
245 * chain, starting from the last bridge to the first. These are called before
246 * calling the encoder's prepare op.
247 *
248 * Note: the bridge passed should be the one closest to the encoder
249 */
250 void drm_bridge_disable(struct drm_bridge *bridge)
251 {
252 if (!bridge)
253 return;
254
255 drm_bridge_disable(bridge->next);
256
257 if (bridge->funcs->disable)
258 bridge->funcs->disable(bridge);
259 }
260 EXPORT_SYMBOL(drm_bridge_disable);
261
262 /**
263 * drm_bridge_post_disable - cleans up after disabling all bridges in the encoder chain
264 * @bridge: bridge control structure
265 *
266 * Calls &drm_bridge_funcs.post_disable op for all the bridges in the
267 * encoder chain, starting from the first bridge to the last. These are called
268 * after completing the encoder's prepare op.
269 *
270 * Note: the bridge passed should be the one closest to the encoder
271 */
272 void drm_bridge_post_disable(struct drm_bridge *bridge)
273 {
274 if (!bridge)
275 return;
276
277 if (bridge->funcs->post_disable)
278 bridge->funcs->post_disable(bridge);
279
280 drm_bridge_post_disable(bridge->next);
281 }
282 EXPORT_SYMBOL(drm_bridge_post_disable);
283
284 /**
285 * drm_bridge_mode_set - set proposed mode for all bridges in the
286 * encoder chain
287 * @bridge: bridge control structure
288 * @mode: desired mode to be set for the bridge
289 * @adjusted_mode: updated mode that works for this bridge
290 *
291 * Calls &drm_bridge_funcs.mode_set op for all the bridges in the
292 * encoder chain, starting from the first bridge to the last.
293 *
294 * Note: the bridge passed should be the one closest to the encoder
295 */
296 void drm_bridge_mode_set(struct drm_bridge *bridge,
297 const struct drm_display_mode *mode,
298 const struct drm_display_mode *adjusted_mode)
299 {
300 if (!bridge)
301 return;
302
303 if (bridge->funcs->mode_set)
304 bridge->funcs->mode_set(bridge, mode, adjusted_mode);
305
306 drm_bridge_mode_set(bridge->next, mode, adjusted_mode);
307 }
308 EXPORT_SYMBOL(drm_bridge_mode_set);
309
310 /**
311 * drm_bridge_pre_enable - prepares for enabling all
312 * bridges in the encoder chain
313 * @bridge: bridge control structure
314 *
315 * Calls &drm_bridge_funcs.pre_enable op for all the bridges in the encoder
316 * chain, starting from the last bridge to the first. These are called
317 * before calling the encoder's commit op.
318 *
319 * Note: the bridge passed should be the one closest to the encoder
320 */
321 void drm_bridge_pre_enable(struct drm_bridge *bridge)
322 {
323 if (!bridge)
324 return;
325
326 drm_bridge_pre_enable(bridge->next);
327
328 if (bridge->funcs->pre_enable)
329 bridge->funcs->pre_enable(bridge);
330 }
331 EXPORT_SYMBOL(drm_bridge_pre_enable);
332
333 /**
334 * drm_bridge_enable - enables all bridges in the encoder chain
335 * @bridge: bridge control structure
336 *
337 * Calls &drm_bridge_funcs.enable op for all the bridges in the encoder
338 * chain, starting from the first bridge to the last. These are called
339 * after completing the encoder's commit op.
340 *
341 * Note that the bridge passed should be the one closest to the encoder
342 */
343 void drm_bridge_enable(struct drm_bridge *bridge)
344 {
345 if (!bridge)
346 return;
347
348 if (bridge->funcs->enable)
349 bridge->funcs->enable(bridge);
350
351 drm_bridge_enable(bridge->next);
352 }
353 EXPORT_SYMBOL(drm_bridge_enable);
354
355 /**
356 * drm_atomic_bridge_disable - disables all bridges in the encoder chain
357 * @bridge: bridge control structure
358 * @state: atomic state being committed
359 *
360 * Calls &drm_bridge_funcs.atomic_disable (falls back on
361 * &drm_bridge_funcs.disable) op for all the bridges in the encoder chain,
362 * starting from the last bridge to the first. These are called before calling
363 * &drm_encoder_helper_funcs.atomic_disable
364 *
365 * Note: the bridge passed should be the one closest to the encoder
366 */
367 void drm_atomic_bridge_disable(struct drm_bridge *bridge,
368 struct drm_atomic_state *state)
369 {
370 if (!bridge)
371 return;
372
373 drm_atomic_bridge_disable(bridge->next, state);
374
375 if (bridge->funcs->atomic_disable)
376 bridge->funcs->atomic_disable(bridge, state);
377 else if (bridge->funcs->disable)
378 bridge->funcs->disable(bridge);
379 }
380 EXPORT_SYMBOL(drm_atomic_bridge_disable);
381
382 /**
383 * drm_atomic_bridge_post_disable - cleans up after disabling all bridges in the
384 * encoder chain
385 * @bridge: bridge control structure
386 * @state: atomic state being committed
387 *
388 * Calls &drm_bridge_funcs.atomic_post_disable (falls back on
389 * &drm_bridge_funcs.post_disable) op for all the bridges in the encoder chain,
390 * starting from the first bridge to the last. These are called after completing
391 * &drm_encoder_helper_funcs.atomic_disable
392 *
393 * Note: the bridge passed should be the one closest to the encoder
394 */
395 void drm_atomic_bridge_post_disable(struct drm_bridge *bridge,
396 struct drm_atomic_state *state)
397 {
398 if (!bridge)
399 return;
400
401 if (bridge->funcs->atomic_post_disable)
402 bridge->funcs->atomic_post_disable(bridge, state);
403 else if (bridge->funcs->post_disable)
404 bridge->funcs->post_disable(bridge);
405
406 drm_atomic_bridge_post_disable(bridge->next, state);
407 }
408 EXPORT_SYMBOL(drm_atomic_bridge_post_disable);
409
410 /**
411 * drm_atomic_bridge_pre_enable - prepares for enabling all bridges in the
412 * encoder chain
413 * @bridge: bridge control structure
414 * @state: atomic state being committed
415 *
416 * Calls &drm_bridge_funcs.atomic_pre_enable (falls back on
417 * &drm_bridge_funcs.pre_enable) op for all the bridges in the encoder chain,
418 * starting from the last bridge to the first. These are called before calling
419 * &drm_encoder_helper_funcs.atomic_enable
420 *
421 * Note: the bridge passed should be the one closest to the encoder
422 */
423 void drm_atomic_bridge_pre_enable(struct drm_bridge *bridge,
424 struct drm_atomic_state *state)
425 {
426 if (!bridge)
427 return;
428
429 drm_atomic_bridge_pre_enable(bridge->next, state);
430
431 if (bridge->funcs->atomic_pre_enable)
432 bridge->funcs->atomic_pre_enable(bridge, state);
433 else if (bridge->funcs->pre_enable)
434 bridge->funcs->pre_enable(bridge);
435 }
436 EXPORT_SYMBOL(drm_atomic_bridge_pre_enable);
437
438 /**
439 * drm_atomic_bridge_enable - enables all bridges in the encoder chain
440 * @bridge: bridge control structure
441 * @state: atomic state being committed
442 *
443 * Calls &drm_bridge_funcs.atomic_enable (falls back on
444 * &drm_bridge_funcs.enable) op for all the bridges in the encoder chain,
445 * starting from the first bridge to the last. These are called after completing
446 * &drm_encoder_helper_funcs.atomic_enable
447 *
448 * Note: the bridge passed should be the one closest to the encoder
449 */
450 void drm_atomic_bridge_enable(struct drm_bridge *bridge,
451 struct drm_atomic_state *state)
452 {
453 if (!bridge)
454 return;
455
456 if (bridge->funcs->atomic_enable)
457 bridge->funcs->atomic_enable(bridge, state);
458 else if (bridge->funcs->enable)
459 bridge->funcs->enable(bridge);
460
461 drm_atomic_bridge_enable(bridge->next, state);
462 }
463 EXPORT_SYMBOL(drm_atomic_bridge_enable);
464
465 #ifdef CONFIG_OF
466 /**
467 * of_drm_find_bridge - find the bridge corresponding to the device node in
468 * the global bridge list
469 *
470 * @np: device node
471 *
472 * RETURNS:
473 * drm_bridge control struct on success, NULL on failure
474 */
475 struct drm_bridge *of_drm_find_bridge(struct device_node *np)
476 {
477 struct drm_bridge *bridge;
478
479 mutex_lock(&bridge_lock);
480
481 list_for_each_entry(bridge, &bridge_list, list) {
482 if (bridge->of_node == np) {
483 mutex_unlock(&bridge_lock);
484 return bridge;
485 }
486 }
487
488 mutex_unlock(&bridge_lock);
489 return NULL;
490 }
491 EXPORT_SYMBOL(of_drm_find_bridge);
492 #endif
493
494 MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
495 MODULE_DESCRIPTION("DRM bridge infrastructure");
496 MODULE_LICENSE("GPL and additional rights");