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_edid.h> 29 #include <drm/drm_print.h> 30 #include <drm/drm_probe_helper.h> 31 32 #define EDID_EXT_BLOCK_CNT 0x7E 33 34 #define STDP4028_IRQ_OUT_CONF_REG 0x02 35 #define STDP4028_DPTX_IRQ_EN_REG 0x3C 36 #define STDP4028_DPTX_IRQ_STS_REG 0x3D 37 #define STDP4028_DPTX_STS_REG 0x3E 38 39 #define STDP4028_DPTX_DP_IRQ_EN 0x1000 40 41 #define STDP4028_DPTX_HOTPLUG_IRQ_EN 0x0400 42 #define STDP4028_DPTX_LINK_CH_IRQ_EN 0x2000 43 #define STDP4028_DPTX_IRQ_CONFIG \ 44 (STDP4028_DPTX_LINK_CH_IRQ_EN | STDP4028_DPTX_HOTPLUG_IRQ_EN) 45 46 #define STDP4028_DPTX_HOTPLUG_STS 0x0200 47 #define STDP4028_DPTX_LINK_STS 0x1000 48 #define STDP4028_CON_STATE_CONNECTED \ 49 (STDP4028_DPTX_HOTPLUG_STS | STDP4028_DPTX_LINK_STS) 50 51 #define STDP4028_DPTX_HOTPLUG_CH_STS 0x0400 52 #define STDP4028_DPTX_LINK_CH_STS 0x2000 53 #define STDP4028_DPTX_IRQ_CLEAR \ 54 (STDP4028_DPTX_LINK_CH_STS | STDP4028_DPTX_HOTPLUG_CH_STS) 55 56 static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex); 57 58 struct ge_b850v3_lvds { 59 struct drm_connector connector; 60 struct drm_bridge bridge; 61 struct i2c_client *stdp4028_i2c; 62 struct i2c_client *stdp2690_i2c; 63 struct edid *edid; 64 }; 65 66 static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr; 67 68 static u8 *stdp2690_get_edid(struct i2c_client *client) 69 { 70 struct i2c_adapter *adapter = client->adapter; 71 unsigned char start = 0x00; 72 unsigned int total_size; 73 u8 *block = kmalloc(EDID_LENGTH, GFP_KERNEL); 74 75 struct i2c_msg msgs[] = { 76 { 77 .addr = client->addr, 78 .flags = 0, 79 .len = 1, 80 .buf = &start, 81 }, { 82 .addr = client->addr, 83 .flags = I2C_M_RD, 84 .len = EDID_LENGTH, 85 .buf = block, 86 } 87 }; 88 89 if (!block) 90 return NULL; 91 92 if (i2c_transfer(adapter, msgs, 2) != 2) { 93 DRM_ERROR("Unable to read EDID.\n"); 94 goto err; 95 } 96 97 if (!drm_edid_block_valid(block, 0, false, NULL)) { 98 DRM_ERROR("Invalid EDID data\n"); 99 goto err; 100 } 101 102 total_size = (block[EDID_EXT_BLOCK_CNT] + 1) * EDID_LENGTH; 103 if (total_size > EDID_LENGTH) { 104 kfree(block); 105 block = kmalloc(total_size, GFP_KERNEL); 106 if (!block) 107 return NULL; 108 109 /* Yes, read the entire buffer, and do not skip the first 110 * EDID_LENGTH bytes. 111 */ 112 start = 0x00; 113 msgs[1].len = total_size; 114 msgs[1].buf = block; 115 116 if (i2c_transfer(adapter, msgs, 2) != 2) { 117 DRM_ERROR("Unable to read EDID extension blocks.\n"); 118 goto err; 119 } 120 if (!drm_edid_block_valid(block, 1, false, NULL)) { 121 DRM_ERROR("Invalid EDID data\n"); 122 goto err; 123 } 124 } 125 126 return block; 127 128 err: 129 kfree(block); 130 return NULL; 131 } 132 133 static int ge_b850v3_lvds_get_modes(struct drm_connector *connector) 134 { 135 struct i2c_client *client; 136 int num_modes = 0; 137 138 client = ge_b850v3_lvds_ptr->stdp2690_i2c; 139 140 kfree(ge_b850v3_lvds_ptr->edid); 141 ge_b850v3_lvds_ptr->edid = (struct edid *)stdp2690_get_edid(client); 142 143 if (ge_b850v3_lvds_ptr->edid) { 144 drm_connector_update_edid_property(connector, 145 ge_b850v3_lvds_ptr->edid); 146 num_modes = drm_add_edid_modes(connector, 147 ge_b850v3_lvds_ptr->edid); 148 } 149 150 return num_modes; 151 } 152 153 static enum drm_mode_status ge_b850v3_lvds_mode_valid( 154 struct drm_connector *connector, struct drm_display_mode *mode) 155 { 156 return MODE_OK; 157 } 158 159 static const struct 160 drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = { 161 .get_modes = ge_b850v3_lvds_get_modes, 162 .mode_valid = ge_b850v3_lvds_mode_valid, 163 }; 164 165 static enum drm_connector_status ge_b850v3_lvds_detect( 166 struct drm_connector *connector, bool force) 167 { 168 struct i2c_client *stdp4028_i2c = 169 ge_b850v3_lvds_ptr->stdp4028_i2c; 170 s32 link_state; 171 172 link_state = i2c_smbus_read_word_data(stdp4028_i2c, 173 STDP4028_DPTX_STS_REG); 174 175 if (link_state == STDP4028_CON_STATE_CONNECTED) 176 return connector_status_connected; 177 178 if (link_state == 0) 179 return connector_status_disconnected; 180 181 return connector_status_unknown; 182 } 183 184 static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = { 185 .fill_modes = drm_helper_probe_single_connector_modes, 186 .detect = ge_b850v3_lvds_detect, 187 .destroy = drm_connector_cleanup, 188 .reset = drm_atomic_helper_connector_reset, 189 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, 190 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, 191 }; 192 193 static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id) 194 { 195 struct i2c_client *stdp4028_i2c 196 = ge_b850v3_lvds_ptr->stdp4028_i2c; 197 198 i2c_smbus_write_word_data(stdp4028_i2c, 199 STDP4028_DPTX_IRQ_STS_REG, 200 STDP4028_DPTX_IRQ_CLEAR); 201 202 if (ge_b850v3_lvds_ptr->connector.dev) 203 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->connector.dev); 204 205 return IRQ_HANDLED; 206 } 207 208 static int ge_b850v3_lvds_attach(struct drm_bridge *bridge) 209 { 210 struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector; 211 struct i2c_client *stdp4028_i2c 212 = ge_b850v3_lvds_ptr->stdp4028_i2c; 213 int ret; 214 215 if (!bridge->encoder) { 216 DRM_ERROR("Parent encoder object not found"); 217 return -ENODEV; 218 } 219 220 connector->polled = DRM_CONNECTOR_POLL_HPD; 221 222 drm_connector_helper_add(connector, 223 &ge_b850v3_lvds_connector_helper_funcs); 224 225 ret = drm_connector_init(bridge->dev, connector, 226 &ge_b850v3_lvds_connector_funcs, 227 DRM_MODE_CONNECTOR_DisplayPort); 228 if (ret) { 229 DRM_ERROR("Failed to initialize connector with drm\n"); 230 return ret; 231 } 232 233 ret = drm_connector_attach_encoder(connector, bridge->encoder); 234 if (ret) 235 return ret; 236 237 /* Configures the bridge to re-enable interrupts after each ack. */ 238 i2c_smbus_write_word_data(stdp4028_i2c, 239 STDP4028_IRQ_OUT_CONF_REG, 240 STDP4028_DPTX_DP_IRQ_EN); 241 242 /* Enable interrupts */ 243 i2c_smbus_write_word_data(stdp4028_i2c, 244 STDP4028_DPTX_IRQ_EN_REG, 245 STDP4028_DPTX_IRQ_CONFIG); 246 247 return 0; 248 } 249 250 static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = { 251 .attach = ge_b850v3_lvds_attach, 252 }; 253 254 static int ge_b850v3_lvds_init(struct device *dev) 255 { 256 mutex_lock(&ge_b850v3_lvds_dev_mutex); 257 258 if (ge_b850v3_lvds_ptr) 259 goto success; 260 261 ge_b850v3_lvds_ptr = devm_kzalloc(dev, 262 sizeof(*ge_b850v3_lvds_ptr), 263 GFP_KERNEL); 264 265 if (!ge_b850v3_lvds_ptr) { 266 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 267 return -ENOMEM; 268 } 269 270 success: 271 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 272 return 0; 273 } 274 275 static void ge_b850v3_lvds_remove(void) 276 { 277 mutex_lock(&ge_b850v3_lvds_dev_mutex); 278 /* 279 * This check is to avoid both the drivers 280 * removing the bridge in their remove() function 281 */ 282 if (!ge_b850v3_lvds_ptr) 283 goto out; 284 285 drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge); 286 287 kfree(ge_b850v3_lvds_ptr->edid); 288 289 ge_b850v3_lvds_ptr = NULL; 290 out: 291 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 292 } 293 294 static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c, 295 const struct i2c_device_id *id) 296 { 297 struct device *dev = &stdp4028_i2c->dev; 298 299 ge_b850v3_lvds_init(dev); 300 301 ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c; 302 i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr); 303 304 /* drm bridge initialization */ 305 ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs; 306 ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node; 307 drm_bridge_add(&ge_b850v3_lvds_ptr->bridge); 308 309 /* Clear pending interrupts since power up. */ 310 i2c_smbus_write_word_data(stdp4028_i2c, 311 STDP4028_DPTX_IRQ_STS_REG, 312 STDP4028_DPTX_IRQ_CLEAR); 313 314 if (!stdp4028_i2c->irq) 315 return 0; 316 317 return devm_request_threaded_irq(&stdp4028_i2c->dev, 318 stdp4028_i2c->irq, NULL, 319 ge_b850v3_lvds_irq_handler, 320 IRQF_TRIGGER_HIGH | IRQF_ONESHOT, 321 "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr); 322 } 323 324 static int stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c) 325 { 326 ge_b850v3_lvds_remove(); 327 328 return 0; 329 } 330 331 static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = { 332 {"stdp4028_ge_fw", 0}, 333 {}, 334 }; 335 MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table); 336 337 static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = { 338 { .compatible = "megachips,stdp4028-ge-b850v3-fw" }, 339 {}, 340 }; 341 MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match); 342 343 static struct i2c_driver stdp4028_ge_b850v3_fw_driver = { 344 .id_table = stdp4028_ge_b850v3_fw_i2c_table, 345 .probe = stdp4028_ge_b850v3_fw_probe, 346 .remove = stdp4028_ge_b850v3_fw_remove, 347 .driver = { 348 .name = "stdp4028-ge-b850v3-fw", 349 .of_match_table = stdp4028_ge_b850v3_fw_match, 350 }, 351 }; 352 353 static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c, 354 const struct i2c_device_id *id) 355 { 356 struct device *dev = &stdp2690_i2c->dev; 357 358 ge_b850v3_lvds_init(dev); 359 360 ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c; 361 i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr); 362 363 return 0; 364 } 365 366 static int stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c) 367 { 368 ge_b850v3_lvds_remove(); 369 370 return 0; 371 } 372 373 static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = { 374 {"stdp2690_ge_fw", 0}, 375 {}, 376 }; 377 MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table); 378 379 static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = { 380 { .compatible = "megachips,stdp2690-ge-b850v3-fw" }, 381 {}, 382 }; 383 MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match); 384 385 static struct i2c_driver stdp2690_ge_b850v3_fw_driver = { 386 .id_table = stdp2690_ge_b850v3_fw_i2c_table, 387 .probe = stdp2690_ge_b850v3_fw_probe, 388 .remove = stdp2690_ge_b850v3_fw_remove, 389 .driver = { 390 .name = "stdp2690-ge-b850v3-fw", 391 .of_match_table = stdp2690_ge_b850v3_fw_match, 392 }, 393 }; 394 395 static int __init stdpxxxx_ge_b850v3_init(void) 396 { 397 int ret; 398 399 ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver); 400 if (ret) 401 return ret; 402 403 return i2c_add_driver(&stdp2690_ge_b850v3_fw_driver); 404 } 405 module_init(stdpxxxx_ge_b850v3_init); 406 407 static void __exit stdpxxxx_ge_b850v3_exit(void) 408 { 409 i2c_del_driver(&stdp2690_ge_b850v3_fw_driver); 410 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver); 411 } 412 module_exit(stdpxxxx_ge_b850v3_exit); 413 414 MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>"); 415 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>"); 416 MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)"); 417 MODULE_LICENSE("GPL v2"); 418