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 struct drm_display_mode *mode, 298 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 #ifdef CONFIG_OF 356 /** 357 * of_drm_find_bridge - find the bridge corresponding to the device node in 358 * the global bridge list 359 * 360 * @np: device node 361 * 362 * RETURNS: 363 * drm_bridge control struct on success, NULL on failure 364 */ 365 struct drm_bridge *of_drm_find_bridge(struct device_node *np) 366 { 367 struct drm_bridge *bridge; 368 369 mutex_lock(&bridge_lock); 370 371 list_for_each_entry(bridge, &bridge_list, list) { 372 if (bridge->of_node == np) { 373 mutex_unlock(&bridge_lock); 374 return bridge; 375 } 376 } 377 378 mutex_unlock(&bridge_lock); 379 return NULL; 380 } 381 EXPORT_SYMBOL(of_drm_find_bridge); 382 #endif 383 384 MODULE_AUTHOR("Ajay Kumar <ajaykumar.rs@samsung.com>"); 385 MODULE_DESCRIPTION("DRM bridge infrastructure"); 386 MODULE_LICENSE("GPL and additional rights"); 387