1// SPDX-License-Identifier: GPL-2.0+ 2/* 3 * Copyright (C) 2019 Laurent Pinchart <laurent.pinchart@ideasonboard.com> 4 */ 5 6#include <linux/kernel.h> 7#include <linux/module.h> 8#include <linux/slab.h> 9 10#include <drm/drm_atomic_state_helper.h> 11#include <drm/drm_bridge.h> 12#include <drm/drm_bridge_connector.h> 13#include <drm/drm_connector.h> 14#include <drm/drm_device.h> 15#include <drm/drm_edid.h> 16#include <drm/drm_modeset_helper_vtables.h> 17#include <drm/drm_probe_helper.h> 18 19/** 20 * DOC: overview 21 * 22 * The DRM bridge connector helper object provides a DRM connector 23 * implementation that wraps a chain of &struct drm_bridge. The connector 24 * operations are fully implemented based on the operations of the bridges in 25 * the chain, and don't require any intervention from the display controller 26 * driver at runtime. 27 * 28 * To use the helper, display controller drivers create a bridge connector with 29 * a call to drm_bridge_connector_init(). This associates the newly created 30 * connector with the chain of bridges passed to the function and registers it 31 * with the DRM device. At that point the connector becomes fully usable, no 32 * further operation is needed. 33 * 34 * The DRM bridge connector operations are implemented based on the operations 35 * provided by the bridges in the chain. Each connector operation is delegated 36 * to the bridge closest to the connector (at the end of the chain) that 37 * provides the relevant functionality. 38 * 39 * To make use of this helper, all bridges in the chain shall report bridge 40 * operation flags (&drm_bridge->ops) and bridge output type 41 * (&drm_bridge->type), as well as the DRM_BRIDGE_ATTACH_NO_CONNECTOR attach 42 * flag (none of the bridges shall create a DRM connector directly). 43 */ 44 45/** 46 * struct drm_bridge_connector - A connector backed by a chain of bridges 47 */ 48struct drm_bridge_connector { 49 /** 50 * @base: The base DRM connector 51 */ 52 struct drm_connector base; 53 /** 54 * @encoder: 55 * 56 * The encoder at the start of the bridges chain. 57 */ 58 struct drm_encoder *encoder; 59 /** 60 * @bridge_edid: 61 * 62 * The last bridge in the chain (closest to the connector) that provides 63 * EDID read support, if any (see &DRM_BRIDGE_OP_EDID). 64 */ 65 struct drm_bridge *bridge_edid; 66 /** 67 * @bridge_hpd: 68 * 69 * The last bridge in the chain (closest to the connector) that provides 70 * hot-plug detection notification, if any (see &DRM_BRIDGE_OP_HPD). 71 */ 72 struct drm_bridge *bridge_hpd; 73 /** 74 * @bridge_detect: 75 * 76 * The last bridge in the chain (closest to the connector) that provides 77 * connector detection, if any (see &DRM_BRIDGE_OP_DETECT). 78 */ 79 struct drm_bridge *bridge_detect; 80 /** 81 * @bridge_modes: 82 * 83 * The last bridge in the chain (closest to the connector) that provides 84 * connector modes detection, if any (see &DRM_BRIDGE_OP_MODES). 85 */ 86 struct drm_bridge *bridge_modes; 87}; 88 89#define to_drm_bridge_connector(x) \ 90 container_of(x, struct drm_bridge_connector, base) 91 92/* ----------------------------------------------------------------------------- 93 * Bridge Connector Hot-Plug Handling 94 */ 95 96static void drm_bridge_connector_hpd_notify(struct drm_connector *connector, 97 enum drm_connector_status status) 98{ 99 struct drm_bridge_connector *bridge_connector = 100 to_drm_bridge_connector(connector); 101 struct drm_bridge *bridge; 102 103 /* Notify all bridges in the pipeline of hotplug events. */ 104 drm_for_each_bridge_in_chain(bridge_connector->encoder, bridge) { 105 if (bridge->funcs->hpd_notify) 106 bridge->funcs->hpd_notify(bridge, status); 107 } 108} 109 110static void drm_bridge_connector_hpd_cb(void *cb_data, 111 enum drm_connector_status status) 112{ 113 struct drm_bridge_connector *drm_bridge_connector = cb_data; 114 struct drm_connector *connector = &drm_bridge_connector->base; 115 struct drm_device *dev = connector->dev; 116 enum drm_connector_status old_status; 117 118 mutex_lock(&dev->mode_config.mutex); 119 old_status = connector->status; 120 connector->status = status; 121 mutex_unlock(&dev->mode_config.mutex); 122 123 if (old_status == status) 124 return; 125 126 drm_bridge_connector_hpd_notify(connector, status); 127 128 drm_kms_helper_connector_hotplug_event(connector); 129} 130 131static void drm_bridge_connector_enable_hpd(struct drm_connector *connector) 132{ 133 struct drm_bridge_connector *bridge_connector = 134 to_drm_bridge_connector(connector); 135 struct drm_bridge *hpd = bridge_connector->bridge_hpd; 136 137 if (hpd) 138 drm_bridge_hpd_enable(hpd, drm_bridge_connector_hpd_cb, 139 bridge_connector); 140} 141 142static void drm_bridge_connector_disable_hpd(struct drm_connector *connector) 143{ 144 struct drm_bridge_connector *bridge_connector = 145 to_drm_bridge_connector(connector); 146 struct drm_bridge *hpd = bridge_connector->bridge_hpd; 147 148 if (hpd) 149 drm_bridge_hpd_disable(hpd); 150} 151 152/* ----------------------------------------------------------------------------- 153 * Bridge Connector Functions 154 */ 155 156static enum drm_connector_status 157drm_bridge_connector_detect(struct drm_connector *connector, bool force) 158{ 159 struct drm_bridge_connector *bridge_connector = 160 to_drm_bridge_connector(connector); 161 struct drm_bridge *detect = bridge_connector->bridge_detect; 162 enum drm_connector_status status; 163 164 if (detect) { 165 status = detect->funcs->detect(detect); 166 167 drm_bridge_connector_hpd_notify(connector, status); 168 } else { 169 switch (connector->connector_type) { 170 case DRM_MODE_CONNECTOR_DPI: 171 case DRM_MODE_CONNECTOR_LVDS: 172 case DRM_MODE_CONNECTOR_DSI: 173 case DRM_MODE_CONNECTOR_eDP: 174 status = connector_status_connected; 175 break; 176 default: 177 status = connector_status_unknown; 178 break; 179 } 180 } 181 182 return status; 183} 184 185static void drm_bridge_connector_destroy(struct drm_connector *connector) 186{ 187 struct drm_bridge_connector *bridge_connector = 188 to_drm_bridge_connector(connector); 189 190 if (bridge_connector->bridge_hpd) { 191 struct drm_bridge *hpd = bridge_connector->bridge_hpd; 192 193 drm_bridge_hpd_disable(hpd); 194 } 195 196 drm_connector_unregister(connector); 197 drm_connector_cleanup(connector); 198 199 kfree(bridge_connector); 200} 201 202static void drm_bridge_connector_debugfs_init(struct drm_connector *connector, 203 struct dentry *root) 204{ 205 struct drm_bridge_connector *bridge_connector = 206 to_drm_bridge_connector(connector); 207 struct drm_encoder *encoder = bridge_connector->encoder; 208 struct drm_bridge *bridge; 209 210 list_for_each_entry(bridge, &encoder->bridge_chain, chain_node) { 211 if (bridge->funcs->debugfs_init) 212 bridge->funcs->debugfs_init(bridge, root); 213 } 214} 215 216static const struct drm_connector_funcs drm_bridge_connector_funcs = { 217 .reset = drm_atomic_helper_connector_reset, 218 .detect = drm_bridge_connector_detect, 219 .fill_modes = drm_helper_probe_single_connector_modes, 220 .destroy = drm_bridge_connector_destroy, 221 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, 222 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, 223 .debugfs_init = drm_bridge_connector_debugfs_init, 224}; 225 226/* ----------------------------------------------------------------------------- 227 * Bridge Connector Helper Functions 228 */ 229 230static int drm_bridge_connector_get_modes_edid(struct drm_connector *connector, 231 struct drm_bridge *bridge) 232{ 233 enum drm_connector_status status; 234 struct edid *edid; 235 int n; 236 237 status = drm_bridge_connector_detect(connector, false); 238 if (status != connector_status_connected) 239 goto no_edid; 240 241 edid = bridge->funcs->get_edid(bridge, connector); 242 if (!drm_edid_is_valid(edid)) { 243 kfree(edid); 244 goto no_edid; 245 } 246 247 drm_connector_update_edid_property(connector, edid); 248 n = drm_add_edid_modes(connector, edid); 249 250 kfree(edid); 251 return n; 252 253no_edid: 254 drm_connector_update_edid_property(connector, NULL); 255 return 0; 256} 257 258static int drm_bridge_connector_get_modes(struct drm_connector *connector) 259{ 260 struct drm_bridge_connector *bridge_connector = 261 to_drm_bridge_connector(connector); 262 struct drm_bridge *bridge; 263 264 /* 265 * If display exposes EDID, then we parse that in the normal way to 266 * build table of supported modes. 267 */ 268 bridge = bridge_connector->bridge_edid; 269 if (bridge) 270 return drm_bridge_connector_get_modes_edid(connector, bridge); 271 272 /* 273 * Otherwise if the display pipeline reports modes (e.g. with a fixed 274 * resolution panel or an analog TV output), query it. 275 */ 276 bridge = bridge_connector->bridge_modes; 277 if (bridge) 278 return bridge->funcs->get_modes(bridge, connector); 279 280 /* 281 * We can't retrieve modes, which can happen for instance for a DVI or 282 * VGA output with the DDC bus unconnected. The KMS core will add the 283 * default modes. 284 */ 285 return 0; 286} 287 288static const struct drm_connector_helper_funcs drm_bridge_connector_helper_funcs = { 289 .get_modes = drm_bridge_connector_get_modes, 290 /* No need for .mode_valid(), the bridges are checked by the core. */ 291 .enable_hpd = drm_bridge_connector_enable_hpd, 292 .disable_hpd = drm_bridge_connector_disable_hpd, 293}; 294 295/* ----------------------------------------------------------------------------- 296 * Bridge Connector Initialisation 297 */ 298 299/** 300 * drm_bridge_connector_init - Initialise a connector for a chain of bridges 301 * @drm: the DRM device 302 * @encoder: the encoder where the bridge chain starts 303 * 304 * Allocate, initialise and register a &drm_bridge_connector with the @drm 305 * device. The connector is associated with a chain of bridges that starts at 306 * the @encoder. All bridges in the chain shall report bridge operation flags 307 * (&drm_bridge->ops) and bridge output type (&drm_bridge->type), and none of 308 * them may create a DRM connector directly. 309 * 310 * Returns a pointer to the new connector on success, or a negative error 311 * pointer otherwise. 312 */ 313struct drm_connector *drm_bridge_connector_init(struct drm_device *drm, 314 struct drm_encoder *encoder) 315{ 316 struct drm_bridge_connector *bridge_connector; 317 struct drm_connector *connector; 318 struct i2c_adapter *ddc = NULL; 319 struct drm_bridge *bridge, *panel_bridge = NULL; 320 int connector_type; 321 int ret; 322 323 bridge_connector = kzalloc(sizeof(*bridge_connector), GFP_KERNEL); 324 if (!bridge_connector) 325 return ERR_PTR(-ENOMEM); 326 327 bridge_connector->encoder = encoder; 328 329 /* 330 * TODO: Handle doublescan_allowed, stereo_allowed and 331 * ycbcr_420_allowed. 332 */ 333 connector = &bridge_connector->base; 334 connector->interlace_allowed = true; 335 336 /* 337 * Initialise connector status handling. First locate the furthest 338 * bridges in the pipeline that support HPD and output detection. Then 339 * initialise the connector polling mode, using HPD if available and 340 * falling back to polling if supported. If neither HPD nor output 341 * detection are available, we don't support hotplug detection at all. 342 */ 343 connector_type = DRM_MODE_CONNECTOR_Unknown; 344 drm_for_each_bridge_in_chain(encoder, bridge) { 345 if (!bridge->interlace_allowed) 346 connector->interlace_allowed = false; 347 348 if (bridge->ops & DRM_BRIDGE_OP_EDID) 349 bridge_connector->bridge_edid = bridge; 350 if (bridge->ops & DRM_BRIDGE_OP_HPD) 351 bridge_connector->bridge_hpd = bridge; 352 if (bridge->ops & DRM_BRIDGE_OP_DETECT) 353 bridge_connector->bridge_detect = bridge; 354 if (bridge->ops & DRM_BRIDGE_OP_MODES) 355 bridge_connector->bridge_modes = bridge; 356 357 if (!drm_bridge_get_next_bridge(bridge)) 358 connector_type = bridge->type; 359 360 if (bridge->ddc) 361 ddc = bridge->ddc; 362 363 if (drm_bridge_is_panel(bridge)) 364 panel_bridge = bridge; 365 } 366 367 if (connector_type == DRM_MODE_CONNECTOR_Unknown) { 368 kfree(bridge_connector); 369 return ERR_PTR(-EINVAL); 370 } 371 372 ret = drm_connector_init_with_ddc(drm, connector, 373 &drm_bridge_connector_funcs, 374 connector_type, ddc); 375 if (ret) { 376 kfree(bridge_connector); 377 return ERR_PTR(ret); 378 } 379 380 drm_connector_helper_add(connector, &drm_bridge_connector_helper_funcs); 381 382 if (bridge_connector->bridge_hpd) 383 connector->polled = DRM_CONNECTOR_POLL_HPD; 384 else if (bridge_connector->bridge_detect) 385 connector->polled = DRM_CONNECTOR_POLL_CONNECT 386 | DRM_CONNECTOR_POLL_DISCONNECT; 387 388 if (panel_bridge) 389 drm_panel_bridge_set_orientation(connector, panel_bridge); 390 391 return connector; 392} 393EXPORT_SYMBOL_GPL(drm_bridge_connector_init); 394