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 const struct 119 drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = { 120 .get_modes = ge_b850v3_lvds_get_modes, 121 }; 122 123 static enum drm_connector_status ge_b850v3_lvds_bridge_detect(struct drm_bridge *bridge) 124 { 125 struct i2c_client *stdp4028_i2c = 126 ge_b850v3_lvds_ptr->stdp4028_i2c; 127 s32 link_state; 128 129 link_state = i2c_smbus_read_word_data(stdp4028_i2c, 130 STDP4028_DPTX_STS_REG); 131 132 if (link_state == STDP4028_CON_STATE_CONNECTED) 133 return connector_status_connected; 134 135 if (link_state == 0) 136 return connector_status_disconnected; 137 138 return connector_status_unknown; 139 } 140 141 static enum drm_connector_status ge_b850v3_lvds_detect(struct drm_connector *connector, 142 bool force) 143 { 144 return ge_b850v3_lvds_bridge_detect(&ge_b850v3_lvds_ptr->bridge); 145 } 146 147 static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = { 148 .fill_modes = drm_helper_probe_single_connector_modes, 149 .detect = ge_b850v3_lvds_detect, 150 .destroy = drm_connector_cleanup, 151 .reset = drm_atomic_helper_connector_reset, 152 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, 153 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, 154 }; 155 156 static int ge_b850v3_lvds_create_connector(struct drm_bridge *bridge) 157 { 158 struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector; 159 int ret; 160 161 connector->polled = DRM_CONNECTOR_POLL_HPD; 162 163 drm_connector_helper_add(connector, 164 &ge_b850v3_lvds_connector_helper_funcs); 165 166 ret = drm_connector_init(bridge->dev, connector, 167 &ge_b850v3_lvds_connector_funcs, 168 DRM_MODE_CONNECTOR_DisplayPort); 169 if (ret) { 170 DRM_ERROR("Failed to initialize connector with drm\n"); 171 return ret; 172 } 173 174 return drm_connector_attach_encoder(connector, bridge->encoder); 175 } 176 177 static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id) 178 { 179 struct i2c_client *stdp4028_i2c 180 = ge_b850v3_lvds_ptr->stdp4028_i2c; 181 182 i2c_smbus_write_word_data(stdp4028_i2c, 183 STDP4028_DPTX_IRQ_STS_REG, 184 STDP4028_DPTX_IRQ_CLEAR); 185 186 if (ge_b850v3_lvds_ptr->bridge.dev) 187 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->bridge.dev); 188 189 return IRQ_HANDLED; 190 } 191 192 static int ge_b850v3_lvds_attach(struct drm_bridge *bridge, 193 struct drm_encoder *encoder, 194 enum drm_bridge_attach_flags flags) 195 { 196 struct i2c_client *stdp4028_i2c 197 = ge_b850v3_lvds_ptr->stdp4028_i2c; 198 199 /* Configures the bridge to re-enable interrupts after each ack. */ 200 i2c_smbus_write_word_data(stdp4028_i2c, 201 STDP4028_IRQ_OUT_CONF_REG, 202 STDP4028_DPTX_DP_IRQ_EN); 203 204 /* Enable interrupts */ 205 i2c_smbus_write_word_data(stdp4028_i2c, 206 STDP4028_DPTX_IRQ_EN_REG, 207 STDP4028_DPTX_IRQ_CONFIG); 208 209 if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR) 210 return 0; 211 212 return ge_b850v3_lvds_create_connector(bridge); 213 } 214 215 static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = { 216 .attach = ge_b850v3_lvds_attach, 217 .detect = ge_b850v3_lvds_bridge_detect, 218 .edid_read = ge_b850v3_lvds_edid_read, 219 }; 220 221 static int ge_b850v3_lvds_init(struct device *dev) 222 { 223 mutex_lock(&ge_b850v3_lvds_dev_mutex); 224 225 if (ge_b850v3_lvds_ptr) 226 goto success; 227 228 ge_b850v3_lvds_ptr = devm_drm_bridge_alloc(dev, struct ge_b850v3_lvds, bridge, 229 &ge_b850v3_lvds_funcs); 230 if (IS_ERR(ge_b850v3_lvds_ptr)) { 231 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 232 return PTR_ERR(ge_b850v3_lvds_ptr); 233 } 234 235 success: 236 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 237 return 0; 238 } 239 240 static void ge_b850v3_lvds_remove(void) 241 { 242 mutex_lock(&ge_b850v3_lvds_dev_mutex); 243 /* 244 * This check is to avoid both the drivers 245 * removing the bridge in their remove() function 246 */ 247 if (!ge_b850v3_lvds_ptr || 248 !ge_b850v3_lvds_ptr->stdp2690_i2c || 249 !ge_b850v3_lvds_ptr->stdp4028_i2c) 250 goto out; 251 252 drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge); 253 254 ge_b850v3_lvds_ptr = NULL; 255 out: 256 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 257 } 258 259 static int ge_b850v3_register(void) 260 { 261 struct i2c_client *stdp4028_i2c = ge_b850v3_lvds_ptr->stdp4028_i2c; 262 struct device *dev = &stdp4028_i2c->dev; 263 264 /* drm bridge initialization */ 265 ge_b850v3_lvds_ptr->bridge.ops = DRM_BRIDGE_OP_DETECT | 266 DRM_BRIDGE_OP_EDID; 267 ge_b850v3_lvds_ptr->bridge.type = DRM_MODE_CONNECTOR_DisplayPort; 268 ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node; 269 drm_bridge_add(&ge_b850v3_lvds_ptr->bridge); 270 271 /* Clear pending interrupts since power up. */ 272 i2c_smbus_write_word_data(stdp4028_i2c, 273 STDP4028_DPTX_IRQ_STS_REG, 274 STDP4028_DPTX_IRQ_CLEAR); 275 276 if (!stdp4028_i2c->irq) 277 return 0; 278 279 return devm_request_threaded_irq(&stdp4028_i2c->dev, 280 stdp4028_i2c->irq, NULL, 281 ge_b850v3_lvds_irq_handler, 282 IRQF_TRIGGER_HIGH | IRQF_ONESHOT, 283 "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr); 284 } 285 286 static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c) 287 { 288 struct device *dev = &stdp4028_i2c->dev; 289 int ret; 290 291 ret = ge_b850v3_lvds_init(dev); 292 293 if (ret) 294 return ret; 295 296 ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c; 297 i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr); 298 299 /* Only register after both bridges are probed */ 300 if (!ge_b850v3_lvds_ptr->stdp2690_i2c) 301 return 0; 302 303 return ge_b850v3_register(); 304 } 305 306 static void stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c) 307 { 308 ge_b850v3_lvds_remove(); 309 } 310 311 static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = { 312 { "stdp4028_ge_fw" }, 313 {} 314 }; 315 MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table); 316 317 static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = { 318 { .compatible = "megachips,stdp4028-ge-b850v3-fw" }, 319 {}, 320 }; 321 MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match); 322 323 static struct i2c_driver stdp4028_ge_b850v3_fw_driver = { 324 .id_table = stdp4028_ge_b850v3_fw_i2c_table, 325 .probe = stdp4028_ge_b850v3_fw_probe, 326 .remove = stdp4028_ge_b850v3_fw_remove, 327 .driver = { 328 .name = "stdp4028-ge-b850v3-fw", 329 .of_match_table = stdp4028_ge_b850v3_fw_match, 330 }, 331 }; 332 333 static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c) 334 { 335 struct device *dev = &stdp2690_i2c->dev; 336 int ret; 337 338 ret = ge_b850v3_lvds_init(dev); 339 340 if (ret) 341 return ret; 342 343 ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c; 344 i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr); 345 346 /* Only register after both bridges are probed */ 347 if (!ge_b850v3_lvds_ptr->stdp4028_i2c) 348 return 0; 349 350 return ge_b850v3_register(); 351 } 352 353 static void stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c) 354 { 355 ge_b850v3_lvds_remove(); 356 } 357 358 static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = { 359 { "stdp2690_ge_fw" }, 360 {} 361 }; 362 MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table); 363 364 static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = { 365 { .compatible = "megachips,stdp2690-ge-b850v3-fw" }, 366 {}, 367 }; 368 MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match); 369 370 static struct i2c_driver stdp2690_ge_b850v3_fw_driver = { 371 .id_table = stdp2690_ge_b850v3_fw_i2c_table, 372 .probe = stdp2690_ge_b850v3_fw_probe, 373 .remove = stdp2690_ge_b850v3_fw_remove, 374 .driver = { 375 .name = "stdp2690-ge-b850v3-fw", 376 .of_match_table = stdp2690_ge_b850v3_fw_match, 377 }, 378 }; 379 380 static int __init stdpxxxx_ge_b850v3_init(void) 381 { 382 int ret; 383 384 ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver); 385 if (ret) 386 return ret; 387 388 ret = i2c_add_driver(&stdp2690_ge_b850v3_fw_driver); 389 if (ret) 390 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver); 391 392 return ret; 393 } 394 module_init(stdpxxxx_ge_b850v3_init); 395 396 static void __exit stdpxxxx_ge_b850v3_exit(void) 397 { 398 i2c_del_driver(&stdp2690_ge_b850v3_fw_driver); 399 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver); 400 } 401 module_exit(stdpxxxx_ge_b850v3_exit); 402 403 MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>"); 404 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>"); 405 MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)"); 406 MODULE_LICENSE("GPL v2"); 407