1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Driver for MegaChips STDP4028 with GE B850v3 firmware (LVDS-DP) 4 * Driver for MegaChips STDP2690 with GE B850v3 firmware (DP-DP++) 5 6 * Copyright (c) 2017, Collabora Ltd. 7 * Copyright (c) 2017, General Electric Company 8 9 10 * This driver creates a drm_bridge and a drm_connector for the LVDS to DP++ 11 * display bridge of the GE B850v3. There are two physical bridges on the video 12 * signal pipeline: a STDP4028(LVDS to DP) and a STDP2690(DP to DP++). The 13 * physical bridges are automatically configured by the input video signal, and 14 * the driver has no access to the video processing pipeline. The driver is 15 * only needed to read EDID from the STDP2690 and to handle HPD events from the 16 * STDP4028. The driver communicates with both bridges over i2c. The video 17 * signal pipeline is as follows: 18 * 19 * Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output 20 */ 21 22 #include <linux/i2c.h> 23 #include <linux/module.h> 24 #include <linux/of.h> 25 26 #include <drm/drm_atomic.h> 27 #include <drm/drm_atomic_helper.h> 28 #include <drm/drm_bridge.h> 29 #include <drm/drm_edid.h> 30 #include <drm/drm_print.h> 31 #include <drm/drm_probe_helper.h> 32 33 #define EDID_EXT_BLOCK_CNT 0x7E 34 35 #define STDP4028_IRQ_OUT_CONF_REG 0x02 36 #define STDP4028_DPTX_IRQ_EN_REG 0x3C 37 #define STDP4028_DPTX_IRQ_STS_REG 0x3D 38 #define STDP4028_DPTX_STS_REG 0x3E 39 40 #define STDP4028_DPTX_DP_IRQ_EN 0x1000 41 42 #define STDP4028_DPTX_HOTPLUG_IRQ_EN 0x0400 43 #define STDP4028_DPTX_LINK_CH_IRQ_EN 0x2000 44 #define STDP4028_DPTX_IRQ_CONFIG \ 45 (STDP4028_DPTX_LINK_CH_IRQ_EN | STDP4028_DPTX_HOTPLUG_IRQ_EN) 46 47 #define STDP4028_DPTX_HOTPLUG_STS 0x0200 48 #define STDP4028_DPTX_LINK_STS 0x1000 49 #define STDP4028_CON_STATE_CONNECTED \ 50 (STDP4028_DPTX_HOTPLUG_STS | STDP4028_DPTX_LINK_STS) 51 52 #define STDP4028_DPTX_HOTPLUG_CH_STS 0x0400 53 #define STDP4028_DPTX_LINK_CH_STS 0x2000 54 #define STDP4028_DPTX_IRQ_CLEAR \ 55 (STDP4028_DPTX_LINK_CH_STS | STDP4028_DPTX_HOTPLUG_CH_STS) 56 57 static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex); 58 59 struct ge_b850v3_lvds { 60 struct drm_connector connector; 61 struct drm_bridge bridge; 62 struct i2c_client *stdp4028_i2c; 63 struct i2c_client *stdp2690_i2c; 64 }; 65 66 static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr; 67 68 static int stdp2690_read_block(void *context, u8 *buf, unsigned int block, size_t len) 69 { 70 struct i2c_client *client = context; 71 struct i2c_adapter *adapter = client->adapter; 72 unsigned char start = block * EDID_LENGTH; 73 74 struct i2c_msg msgs[] = { 75 { 76 .addr = client->addr, 77 .flags = 0, 78 .len = 1, 79 .buf = &start, 80 }, { 81 .addr = client->addr, 82 .flags = I2C_M_RD, 83 .len = len, 84 .buf = buf, 85 } 86 }; 87 88 if (i2c_transfer(adapter, msgs, 2) != 2) 89 return -1; 90 91 return 0; 92 } 93 94 static const struct drm_edid *ge_b850v3_lvds_edid_read(struct drm_bridge *bridge, 95 struct drm_connector *connector) 96 { 97 struct i2c_client *client; 98 99 client = ge_b850v3_lvds_ptr->stdp2690_i2c; 100 101 return drm_edid_read_custom(connector, stdp2690_read_block, client); 102 } 103 104 static int ge_b850v3_lvds_get_modes(struct drm_connector *connector) 105 { 106 const struct drm_edid *drm_edid; 107 int num_modes; 108 109 drm_edid = ge_b850v3_lvds_edid_read(&ge_b850v3_lvds_ptr->bridge, connector); 110 111 drm_edid_connector_update(connector, drm_edid); 112 num_modes = drm_edid_connector_add_modes(connector); 113 drm_edid_free(drm_edid); 114 115 return num_modes; 116 } 117 118 static enum drm_mode_status ge_b850v3_lvds_mode_valid( 119 struct drm_connector *connector, struct drm_display_mode *mode) 120 { 121 return MODE_OK; 122 } 123 124 static const struct 125 drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = { 126 .get_modes = ge_b850v3_lvds_get_modes, 127 .mode_valid = ge_b850v3_lvds_mode_valid, 128 }; 129 130 static enum drm_connector_status ge_b850v3_lvds_bridge_detect(struct drm_bridge *bridge) 131 { 132 struct i2c_client *stdp4028_i2c = 133 ge_b850v3_lvds_ptr->stdp4028_i2c; 134 s32 link_state; 135 136 link_state = i2c_smbus_read_word_data(stdp4028_i2c, 137 STDP4028_DPTX_STS_REG); 138 139 if (link_state == STDP4028_CON_STATE_CONNECTED) 140 return connector_status_connected; 141 142 if (link_state == 0) 143 return connector_status_disconnected; 144 145 return connector_status_unknown; 146 } 147 148 static enum drm_connector_status ge_b850v3_lvds_detect(struct drm_connector *connector, 149 bool force) 150 { 151 return ge_b850v3_lvds_bridge_detect(&ge_b850v3_lvds_ptr->bridge); 152 } 153 154 static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = { 155 .fill_modes = drm_helper_probe_single_connector_modes, 156 .detect = ge_b850v3_lvds_detect, 157 .destroy = drm_connector_cleanup, 158 .reset = drm_atomic_helper_connector_reset, 159 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, 160 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, 161 }; 162 163 static int ge_b850v3_lvds_create_connector(struct drm_bridge *bridge) 164 { 165 struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector; 166 int ret; 167 168 connector->polled = DRM_CONNECTOR_POLL_HPD; 169 170 drm_connector_helper_add(connector, 171 &ge_b850v3_lvds_connector_helper_funcs); 172 173 ret = drm_connector_init(bridge->dev, connector, 174 &ge_b850v3_lvds_connector_funcs, 175 DRM_MODE_CONNECTOR_DisplayPort); 176 if (ret) { 177 DRM_ERROR("Failed to initialize connector with drm\n"); 178 return ret; 179 } 180 181 return drm_connector_attach_encoder(connector, bridge->encoder); 182 } 183 184 static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id) 185 { 186 struct i2c_client *stdp4028_i2c 187 = ge_b850v3_lvds_ptr->stdp4028_i2c; 188 189 i2c_smbus_write_word_data(stdp4028_i2c, 190 STDP4028_DPTX_IRQ_STS_REG, 191 STDP4028_DPTX_IRQ_CLEAR); 192 193 if (ge_b850v3_lvds_ptr->bridge.dev) 194 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->bridge.dev); 195 196 return IRQ_HANDLED; 197 } 198 199 static int ge_b850v3_lvds_attach(struct drm_bridge *bridge, 200 enum drm_bridge_attach_flags flags) 201 { 202 struct i2c_client *stdp4028_i2c 203 = ge_b850v3_lvds_ptr->stdp4028_i2c; 204 205 /* Configures the bridge to re-enable interrupts after each ack. */ 206 i2c_smbus_write_word_data(stdp4028_i2c, 207 STDP4028_IRQ_OUT_CONF_REG, 208 STDP4028_DPTX_DP_IRQ_EN); 209 210 /* Enable interrupts */ 211 i2c_smbus_write_word_data(stdp4028_i2c, 212 STDP4028_DPTX_IRQ_EN_REG, 213 STDP4028_DPTX_IRQ_CONFIG); 214 215 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) 216 return 0; 217 218 return ge_b850v3_lvds_create_connector(bridge); 219 } 220 221 static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = { 222 .attach = ge_b850v3_lvds_attach, 223 .detect = ge_b850v3_lvds_bridge_detect, 224 .edid_read = ge_b850v3_lvds_edid_read, 225 }; 226 227 static int ge_b850v3_lvds_init(struct device *dev) 228 { 229 mutex_lock(&ge_b850v3_lvds_dev_mutex); 230 231 if (ge_b850v3_lvds_ptr) 232 goto success; 233 234 ge_b850v3_lvds_ptr = devm_kzalloc(dev, 235 sizeof(*ge_b850v3_lvds_ptr), 236 GFP_KERNEL); 237 238 if (!ge_b850v3_lvds_ptr) { 239 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 240 return -ENOMEM; 241 } 242 243 success: 244 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 245 return 0; 246 } 247 248 static void ge_b850v3_lvds_remove(void) 249 { 250 mutex_lock(&ge_b850v3_lvds_dev_mutex); 251 /* 252 * This check is to avoid both the drivers 253 * removing the bridge in their remove() function 254 */ 255 if (!ge_b850v3_lvds_ptr || 256 !ge_b850v3_lvds_ptr->stdp2690_i2c || 257 !ge_b850v3_lvds_ptr->stdp4028_i2c) 258 goto out; 259 260 drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge); 261 262 ge_b850v3_lvds_ptr = NULL; 263 out: 264 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 265 } 266 267 static int ge_b850v3_register(void) 268 { 269 struct i2c_client *stdp4028_i2c = ge_b850v3_lvds_ptr->stdp4028_i2c; 270 struct device *dev = &stdp4028_i2c->dev; 271 272 /* drm bridge initialization */ 273 ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs; 274 ge_b850v3_lvds_ptr->bridge.ops = DRM_BRIDGE_OP_DETECT | 275 DRM_BRIDGE_OP_EDID; 276 ge_b850v3_lvds_ptr->bridge.type = DRM_MODE_CONNECTOR_DisplayPort; 277 ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node; 278 drm_bridge_add(&ge_b850v3_lvds_ptr->bridge); 279 280 /* Clear pending interrupts since power up. */ 281 i2c_smbus_write_word_data(stdp4028_i2c, 282 STDP4028_DPTX_IRQ_STS_REG, 283 STDP4028_DPTX_IRQ_CLEAR); 284 285 if (!stdp4028_i2c->irq) 286 return 0; 287 288 return devm_request_threaded_irq(&stdp4028_i2c->dev, 289 stdp4028_i2c->irq, NULL, 290 ge_b850v3_lvds_irq_handler, 291 IRQF_TRIGGER_HIGH | IRQF_ONESHOT, 292 "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr); 293 } 294 295 static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c) 296 { 297 struct device *dev = &stdp4028_i2c->dev; 298 int ret; 299 300 ret = ge_b850v3_lvds_init(dev); 301 302 if (ret) 303 return ret; 304 305 ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c; 306 i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr); 307 308 /* Only register after both bridges are probed */ 309 if (!ge_b850v3_lvds_ptr->stdp2690_i2c) 310 return 0; 311 312 return ge_b850v3_register(); 313 } 314 315 static void stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c) 316 { 317 ge_b850v3_lvds_remove(); 318 } 319 320 static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = { 321 {"stdp4028_ge_fw", 0}, 322 {}, 323 }; 324 MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table); 325 326 static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = { 327 { .compatible = "megachips,stdp4028-ge-b850v3-fw" }, 328 {}, 329 }; 330 MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match); 331 332 static struct i2c_driver stdp4028_ge_b850v3_fw_driver = { 333 .id_table = stdp4028_ge_b850v3_fw_i2c_table, 334 .probe = stdp4028_ge_b850v3_fw_probe, 335 .remove = stdp4028_ge_b850v3_fw_remove, 336 .driver = { 337 .name = "stdp4028-ge-b850v3-fw", 338 .of_match_table = stdp4028_ge_b850v3_fw_match, 339 }, 340 }; 341 342 static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c) 343 { 344 struct device *dev = &stdp2690_i2c->dev; 345 int ret; 346 347 ret = ge_b850v3_lvds_init(dev); 348 349 if (ret) 350 return ret; 351 352 ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c; 353 i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr); 354 355 /* Only register after both bridges are probed */ 356 if (!ge_b850v3_lvds_ptr->stdp4028_i2c) 357 return 0; 358 359 return ge_b850v3_register(); 360 } 361 362 static void stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c) 363 { 364 ge_b850v3_lvds_remove(); 365 } 366 367 static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = { 368 {"stdp2690_ge_fw", 0}, 369 {}, 370 }; 371 MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table); 372 373 static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = { 374 { .compatible = "megachips,stdp2690-ge-b850v3-fw" }, 375 {}, 376 }; 377 MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match); 378 379 static struct i2c_driver stdp2690_ge_b850v3_fw_driver = { 380 .id_table = stdp2690_ge_b850v3_fw_i2c_table, 381 .probe = stdp2690_ge_b850v3_fw_probe, 382 .remove = stdp2690_ge_b850v3_fw_remove, 383 .driver = { 384 .name = "stdp2690-ge-b850v3-fw", 385 .of_match_table = stdp2690_ge_b850v3_fw_match, 386 }, 387 }; 388 389 static int __init stdpxxxx_ge_b850v3_init(void) 390 { 391 int ret; 392 393 ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver); 394 if (ret) 395 return ret; 396 397 ret = i2c_add_driver(&stdp2690_ge_b850v3_fw_driver); 398 if (ret) 399 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver); 400 401 return ret; 402 } 403 module_init(stdpxxxx_ge_b850v3_init); 404 405 static void __exit stdpxxxx_ge_b850v3_exit(void) 406 { 407 i2c_del_driver(&stdp2690_ge_b850v3_fw_driver); 408 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver); 409 } 410 module_exit(stdpxxxx_ge_b850v3_exit); 411 412 MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>"); 413 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>"); 414 MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)"); 415 MODULE_LICENSE("GPL v2"); 416