Loading...
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
27#include <drm/drm_crtc.h>
28
29#include "drm/drmP.h"
30
31/**
32 * DOC: overview
33 *
34 * struct &drm_bridge represents a device that hangs on to an encoder. These are
35 * handy when a regular &drm_encoder entity isn't enough to represent the entire
36 * encoder chain.
37 *
38 * A bridge is always attached to a single &drm_encoder at a time, but can be
39 * either connected to it directly, or through an intermediate bridge:
40 *
41 * encoder ---> bridge B ---> bridge A
42 *
43 * Here, the output of the encoder feeds to bridge B, and that furthers feeds to
44 * bridge A.
45 *
46 * The driver using the bridge is responsible to make the associations between
47 * the encoder and bridges. Once these links are made, the bridges will
48 * participate along with encoder functions to perform mode_set/enable/disable
49 * through the ops provided in &drm_bridge_funcs.
50 *
51 * drm_bridge, like drm_panel, aren't drm_mode_object entities like planes,
52 * CRTCs, encoders or connectors and hence are not visible to userspace. They
53 * just provide additional hooks to get the desired output at the end of the
54 * encoder chain.
55 *
56 * Bridges can also be chained up using the next pointer in struct &drm_bridge.
57 *
58 * Both legacy CRTC helpers and the new atomic modeset helpers support bridges.
59 */
60
61static DEFINE_MUTEX(bridge_lock);
62static LIST_HEAD(bridge_list);
63
64/**
65 * drm_bridge_add - add the given bridge to the global bridge list
66 *
67 * @bridge: bridge control structure
68 *
69 * RETURNS:
70 * Unconditionally returns Zero.
71 */
72int drm_bridge_add(struct drm_bridge *bridge)
73{
74 mutex_lock(&bridge_lock);
75 list_add_tail(&bridge->list, &bridge_list);
76 mutex_unlock(&bridge_lock);
77
78 return 0;
79}
80EXPORT_SYMBOL(drm_bridge_add);
81
82/**
83 * drm_bridge_remove - remove the given bridge from the global bridge list
84 *
85 * @bridge: bridge control structure
86 */
87void drm_bridge_remove(struct drm_bridge *bridge)
88{
89 mutex_lock(&bridge_lock);
90 list_del_init(&bridge->list);
91 mutex_unlock(&bridge_lock);
92}
93EXPORT_SYMBOL(drm_bridge_remove);
94
95/**
96 * drm_bridge_attach - associate given bridge to our DRM device
97 *
98 * @dev: DRM device
99 * @bridge: bridge control structure
100 *
101 * called by a kms driver to link one of our encoder/bridge to the given
102 * bridge.
103 *
104 * Note that setting up links between the bridge and our encoder/bridge
105 * objects needs to be handled by the kms driver itself
106 *
107 * RETURNS:
108 * Zero on success, error code on failure
109 */
110int drm_bridge_attach(struct drm_device *dev, struct drm_bridge *bridge)
111{
112 if (!dev || !bridge)
113 return -EINVAL;
114
115 if (bridge->dev)
116 return -EBUSY;
117
118 bridge->dev = dev;
119
120 if (bridge->funcs->attach)
121 return bridge->funcs->attach(bridge);
122
123 return 0;
124}
125EXPORT_SYMBOL(drm_bridge_attach);
126
127/**
128 * DOC: bridge callbacks
129 *
130 * The &drm_bridge_funcs ops are populated by the bridge driver. The DRM
131 * internals (atomic and CRTC helpers) use the helpers defined in drm_bridge.c
132 * These helpers call a specific &drm_bridge_funcs op for all the bridges
133 * during encoder configuration.
134 *
135 * For detailed specification of the bridge callbacks see &drm_bridge_funcs.
136 */
137
138/**
139 * drm_bridge_mode_fixup - fixup proposed mode for all bridges in the
140 * encoder chain
141 * @bridge: bridge control structure
142 * @mode: desired mode to be set for the bridge
143 * @adjusted_mode: updated mode that works for this bridge
144 *
145 * Calls ->mode_fixup() &drm_bridge_funcs op for all the bridges in the
146 * encoder chain, starting from the first bridge to the last.
147 *
148 * Note: the bridge passed should be the one closest to the encoder
149 *
150 * RETURNS:
151 * true on success, false on failure
152 */
153bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
154 const struct drm_display_mode *mode,
155 struct drm_display_mode *adjusted_mode)
156{
157 bool ret = true;
158
159 if (!bridge)
160 return true;
161
162 if (bridge->funcs->mode_fixup)
163 ret = bridge->funcs->mode_fixup(bridge, mode, adjusted_mode);
164
165 ret = ret && drm_bridge_mode_fixup(bridge->next, mode, adjusted_mode);
166
167 return ret;
168}
169EXPORT_SYMBOL(drm_bridge_mode_fixup);
170
171/**
172 * drm_bridge_disable - calls ->disable() &drm_bridge_funcs op for all
173 * bridges in the encoder chain.
174 * @bridge: bridge control structure
175 *
176 * Calls ->disable() &drm_bridge_funcs op for all the bridges in the encoder
177 * chain, starting from the last bridge to the first. These are called before
178 * calling the encoder's prepare op.
179 *
180 * Note: the bridge passed should be the one closest to the encoder
181 */
182void drm_bridge_disable(struct drm_bridge *bridge)
183{
184 if (!bridge)
185 return;
186
187 drm_bridge_disable(bridge->next);
188
189 if (bridge->funcs->disable)
190 bridge->funcs->disable(bridge);
191}
192EXPORT_SYMBOL(drm_bridge_disable);
193
194/**
195 * drm_bridge_post_disable - calls ->post_disable() &drm_bridge_funcs op for
196 * all bridges in the encoder chain.
197 * @bridge: bridge control structure
198 *
199 * Calls ->post_disable() &drm_bridge_funcs op for all the bridges in the
200 * encoder chain, starting from the first bridge to the last. These are called
201 * after completing the encoder's prepare op.
202 *
203 * Note: the bridge passed should be the one closest to the encoder
204 */
205void drm_bridge_post_disable(struct drm_bridge *bridge)
206{
207 if (!bridge)
208 return;
209
210 if (bridge->funcs->post_disable)
211 bridge->funcs->post_disable(bridge);
212
213 drm_bridge_post_disable(bridge->next);
214}
215EXPORT_SYMBOL(drm_bridge_post_disable);
216
217/**
218 * drm_bridge_mode_set - set proposed mode for all bridges in the
219 * encoder chain
220 * @bridge: bridge control structure
221 * @mode: desired mode to be set for the bridge
222 * @adjusted_mode: updated mode that works for this bridge
223 *
224 * Calls ->mode_set() &drm_bridge_funcs op for all the bridges in the
225 * encoder chain, starting from the first bridge to the last.
226 *
227 * Note: the bridge passed should be the one closest to the encoder
228 */
229void drm_bridge_mode_set(struct drm_bridge *bridge,
230 struct drm_display_mode *mode,
231 struct drm_display_mode *adjusted_mode)
232{
233 if (!bridge)
234 return;
235
236 if (bridge->funcs->mode_set)
237 bridge->funcs->mode_set(bridge, mode, adjusted_mode);
238
239 drm_bridge_mode_set(bridge->next, mode, adjusted_mode);
240}
241EXPORT_SYMBOL(drm_bridge_mode_set);
242
243/**
244 * drm_bridge_pre_enable - calls ->pre_enable() &drm_bridge_funcs op for all
245 * bridges in the encoder chain.
246 * @bridge: bridge control structure
247 *
248 * Calls ->pre_enable() &drm_bridge_funcs op for all the bridges in the encoder
249 * chain, starting from the last bridge to the first. These are called
250 * before calling the encoder's commit op.
251 *
252 * Note: the bridge passed should be the one closest to the encoder
253 */
254void drm_bridge_pre_enable(struct drm_bridge *bridge)
255{
256 if (!bridge)
257 return;
258
259 drm_bridge_pre_enable(bridge->next);
260
261 if (bridge->funcs->pre_enable)
262 bridge->funcs->pre_enable(bridge);
263}
264EXPORT_SYMBOL(drm_bridge_pre_enable);
265
266/**
267 * drm_bridge_enable - calls ->enable() &drm_bridge_funcs op for all bridges
268 * in the encoder chain.
269 * @bridge: bridge control structure
270 *
271 * Calls ->enable() &drm_bridge_funcs op for all the bridges in the encoder
272 * chain, starting from the first bridge to the last. These are called
273 * after completing the encoder's commit op.
274 *
275 * Note that the bridge passed should be the one closest to the encoder
276 */
277void drm_bridge_enable(struct drm_bridge *bridge)
278{
279 if (!bridge)
280 return;
281
282 if (bridge->funcs->enable)
283 bridge->funcs->enable(bridge);
284
285 drm_bridge_enable(bridge->next);
286}
287EXPORT_SYMBOL(drm_bridge_enable);
288
289#ifdef CONFIG_OF
290/**
291 * of_drm_find_bridge - find the bridge corresponding to the device node in
292 * the global bridge list
293 *
294 * @np: device node
295 *
296 * RETURNS:
297 * drm_bridge control struct on success, NULL on failure
298 */
299struct drm_bridge *of_drm_find_bridge(struct device_node *np)
300{
301 struct drm_bridge *bridge;
302
303 mutex_lock(&bridge_lock);
304
305 list_for_each_entry(bridge, &bridge_list, list) {
306 if (bridge->of_node == np) {
307 mutex_unlock(&bridge_lock);
308 return bridge;
309 }
310 }
311
312 mutex_unlock(&bridge_lock);
313 return NULL;
314}
315EXPORT_SYMBOL(of_drm_find_bridge);
316#endif
317
318MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
319MODULE_DESCRIPTION("DRM bridge infrastructure");
320MODULE_LICENSE("GPL and additional rights");
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
63static DEFINE_MUTEX(bridge_lock);
64static 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 */
71void 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}
77EXPORT_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 */
84void 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}
90EXPORT_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 * RETURNS:
108 * Zero on success, error code on failure
109 */
110int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
111 struct drm_bridge *previous)
112{
113 int ret;
114
115 if (!encoder || !bridge)
116 return -EINVAL;
117
118 if (previous && (!previous->dev || previous->encoder != encoder))
119 return -EINVAL;
120
121 if (bridge->dev)
122 return -EBUSY;
123
124 bridge->dev = encoder->dev;
125 bridge->encoder = encoder;
126
127 if (bridge->funcs->attach) {
128 ret = bridge->funcs->attach(bridge);
129 if (ret < 0) {
130 bridge->dev = NULL;
131 bridge->encoder = NULL;
132 return ret;
133 }
134 }
135
136 if (previous)
137 previous->next = bridge;
138 else
139 encoder->bridge = bridge;
140
141 return 0;
142}
143EXPORT_SYMBOL(drm_bridge_attach);
144
145void drm_bridge_detach(struct drm_bridge *bridge)
146{
147 if (WARN_ON(!bridge))
148 return;
149
150 if (WARN_ON(!bridge->dev))
151 return;
152
153 if (bridge->funcs->detach)
154 bridge->funcs->detach(bridge);
155
156 bridge->dev = NULL;
157}
158
159/**
160 * DOC: bridge callbacks
161 *
162 * The &drm_bridge_funcs ops are populated by the bridge driver. The DRM
163 * internals (atomic and CRTC helpers) use the helpers defined in drm_bridge.c
164 * These helpers call a specific &drm_bridge_funcs op for all the bridges
165 * during encoder configuration.
166 *
167 * For detailed specification of the bridge callbacks see &drm_bridge_funcs.
168 */
169
170/**
171 * drm_bridge_mode_fixup - fixup proposed mode for all bridges in the
172 * encoder chain
173 * @bridge: bridge control structure
174 * @mode: desired mode to be set for the bridge
175 * @adjusted_mode: updated mode that works for this bridge
176 *
177 * Calls &drm_bridge_funcs.mode_fixup for all the bridges in the
178 * encoder chain, starting from the first bridge to the last.
179 *
180 * Note: the bridge passed should be the one closest to the encoder
181 *
182 * RETURNS:
183 * true on success, false on failure
184 */
185bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
186 const struct drm_display_mode *mode,
187 struct drm_display_mode *adjusted_mode)
188{
189 bool ret = true;
190
191 if (!bridge)
192 return true;
193
194 if (bridge->funcs->mode_fixup)
195 ret = bridge->funcs->mode_fixup(bridge, mode, adjusted_mode);
196
197 ret = ret && drm_bridge_mode_fixup(bridge->next, mode, adjusted_mode);
198
199 return ret;
200}
201EXPORT_SYMBOL(drm_bridge_mode_fixup);
202
203/**
204 * drm_bridge_mode_valid - validate the mode against all bridges in the
205 * encoder chain.
206 * @bridge: bridge control structure
207 * @mode: desired mode to be validated
208 *
209 * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
210 * chain, starting from the first bridge to the last. If at least one bridge
211 * does not accept the mode the function returns the error code.
212 *
213 * Note: the bridge passed should be the one closest to the encoder.
214 *
215 * RETURNS:
216 * MODE_OK on success, drm_mode_status Enum error code on failure
217 */
218enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
219 const struct drm_display_mode *mode)
220{
221 enum drm_mode_status ret = MODE_OK;
222
223 if (!bridge)
224 return ret;
225
226 if (bridge->funcs->mode_valid)
227 ret = bridge->funcs->mode_valid(bridge, mode);
228
229 if (ret != MODE_OK)
230 return ret;
231
232 return drm_bridge_mode_valid(bridge->next, mode);
233}
234EXPORT_SYMBOL(drm_bridge_mode_valid);
235
236/**
237 * drm_bridge_disable - disables all bridges in the encoder chain
238 * @bridge: bridge control structure
239 *
240 * Calls &drm_bridge_funcs.disable op for all the bridges in the encoder
241 * chain, starting from the last bridge to the first. These are called before
242 * calling the encoder's prepare op.
243 *
244 * Note: the bridge passed should be the one closest to the encoder
245 */
246void drm_bridge_disable(struct drm_bridge *bridge)
247{
248 if (!bridge)
249 return;
250
251 drm_bridge_disable(bridge->next);
252
253 if (bridge->funcs->disable)
254 bridge->funcs->disable(bridge);
255}
256EXPORT_SYMBOL(drm_bridge_disable);
257
258/**
259 * drm_bridge_post_disable - cleans up after disabling all bridges in the encoder chain
260 * @bridge: bridge control structure
261 *
262 * Calls &drm_bridge_funcs.post_disable op for all the bridges in the
263 * encoder chain, starting from the first bridge to the last. These are called
264 * after completing the encoder's prepare op.
265 *
266 * Note: the bridge passed should be the one closest to the encoder
267 */
268void drm_bridge_post_disable(struct drm_bridge *bridge)
269{
270 if (!bridge)
271 return;
272
273 if (bridge->funcs->post_disable)
274 bridge->funcs->post_disable(bridge);
275
276 drm_bridge_post_disable(bridge->next);
277}
278EXPORT_SYMBOL(drm_bridge_post_disable);
279
280/**
281 * drm_bridge_mode_set - set proposed mode for all bridges in the
282 * encoder chain
283 * @bridge: bridge control structure
284 * @mode: desired mode to be set for the bridge
285 * @adjusted_mode: updated mode that works for this bridge
286 *
287 * Calls &drm_bridge_funcs.mode_set op for all the bridges in the
288 * encoder chain, starting from the first bridge to the last.
289 *
290 * Note: the bridge passed should be the one closest to the encoder
291 */
292void drm_bridge_mode_set(struct drm_bridge *bridge,
293 struct drm_display_mode *mode,
294 struct drm_display_mode *adjusted_mode)
295{
296 if (!bridge)
297 return;
298
299 if (bridge->funcs->mode_set)
300 bridge->funcs->mode_set(bridge, mode, adjusted_mode);
301
302 drm_bridge_mode_set(bridge->next, mode, adjusted_mode);
303}
304EXPORT_SYMBOL(drm_bridge_mode_set);
305
306/**
307 * drm_bridge_pre_enable - prepares for enabling all
308 * bridges in the encoder chain
309 * @bridge: bridge control structure
310 *
311 * Calls &drm_bridge_funcs.pre_enable op for all the bridges in the encoder
312 * chain, starting from the last bridge to the first. These are called
313 * before calling the encoder's commit op.
314 *
315 * Note: the bridge passed should be the one closest to the encoder
316 */
317void drm_bridge_pre_enable(struct drm_bridge *bridge)
318{
319 if (!bridge)
320 return;
321
322 drm_bridge_pre_enable(bridge->next);
323
324 if (bridge->funcs->pre_enable)
325 bridge->funcs->pre_enable(bridge);
326}
327EXPORT_SYMBOL(drm_bridge_pre_enable);
328
329/**
330 * drm_bridge_enable - enables all bridges in the encoder chain
331 * @bridge: bridge control structure
332 *
333 * Calls &drm_bridge_funcs.enable op for all the bridges in the encoder
334 * chain, starting from the first bridge to the last. These are called
335 * after completing the encoder's commit op.
336 *
337 * Note that the bridge passed should be the one closest to the encoder
338 */
339void drm_bridge_enable(struct drm_bridge *bridge)
340{
341 if (!bridge)
342 return;
343
344 if (bridge->funcs->enable)
345 bridge->funcs->enable(bridge);
346
347 drm_bridge_enable(bridge->next);
348}
349EXPORT_SYMBOL(drm_bridge_enable);
350
351#ifdef CONFIG_OF
352/**
353 * of_drm_find_bridge - find the bridge corresponding to the device node in
354 * the global bridge list
355 *
356 * @np: device node
357 *
358 * RETURNS:
359 * drm_bridge control struct on success, NULL on failure
360 */
361struct drm_bridge *of_drm_find_bridge(struct device_node *np)
362{
363 struct drm_bridge *bridge;
364
365 mutex_lock(&bridge_lock);
366
367 list_for_each_entry(bridge, &bridge_list, list) {
368 if (bridge->of_node == np) {
369 mutex_unlock(&bridge_lock);
370 return bridge;
371 }
372 }
373
374 mutex_unlock(&bridge_lock);
375 return NULL;
376}
377EXPORT_SYMBOL(of_drm_find_bridge);
378#endif
379
380MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>");
381MODULE_DESCRIPTION("DRM bridge infrastructure");
382MODULE_LICENSE("GPL and additional rights");