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/gpio.h> 23 #include <linux/i2c.h> 24 #include <linux/module.h> 25 #include <linux/of.h> 26 27 #include <drm/drm_atomic.h> 28 #include <drm/drm_atomic_helper.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 struct edid *edid; 65 }; 66 67 static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr; 68 69 static u8 *stdp2690_get_edid(struct i2c_client *client) 70 { 71 struct i2c_adapter *adapter = client->adapter; 72 unsigned char start = 0x00; 73 unsigned int total_size; 74 u8 *block = kmalloc(EDID_LENGTH, GFP_KERNEL); 75 76 struct i2c_msg msgs[] = { 77 { 78 .addr = client->addr, 79 .flags = 0, 80 .len = 1, 81 .buf = &start, 82 }, { 83 .addr = client->addr, 84 .flags = I2C_M_RD, 85 .len = EDID_LENGTH, 86 .buf = block, 87 } 88 }; 89 90 if (!block) 91 return NULL; 92 93 if (i2c_transfer(adapter, msgs, 2) != 2) { 94 DRM_ERROR("Unable to read EDID.\n"); 95 goto err; 96 } 97 98 if (!drm_edid_block_valid(block, 0, false, NULL)) { 99 DRM_ERROR("Invalid EDID data\n"); 100 goto err; 101 } 102 103 total_size = (block[EDID_EXT_BLOCK_CNT] + 1) * EDID_LENGTH; 104 if (total_size > EDID_LENGTH) { 105 kfree(block); 106 block = kmalloc(total_size, GFP_KERNEL); 107 if (!block) 108 return NULL; 109 110 /* Yes, read the entire buffer, and do not skip the first 111 * EDID_LENGTH bytes. 112 */ 113 start = 0x00; 114 msgs[1].len = total_size; 115 msgs[1].buf = block; 116 117 if (i2c_transfer(adapter, msgs, 2) != 2) { 118 DRM_ERROR("Unable to read EDID extension blocks.\n"); 119 goto err; 120 } 121 if (!drm_edid_block_valid(block, 1, false, NULL)) { 122 DRM_ERROR("Invalid EDID data\n"); 123 goto err; 124 } 125 } 126 127 return block; 128 129 err: 130 kfree(block); 131 return NULL; 132 } 133 134 static int ge_b850v3_lvds_get_modes(struct drm_connector *connector) 135 { 136 struct i2c_client *client; 137 int num_modes = 0; 138 139 client = ge_b850v3_lvds_ptr->stdp2690_i2c; 140 141 kfree(ge_b850v3_lvds_ptr->edid); 142 ge_b850v3_lvds_ptr->edid = (struct edid *)stdp2690_get_edid(client); 143 144 if (ge_b850v3_lvds_ptr->edid) { 145 drm_connector_update_edid_property(connector, 146 ge_b850v3_lvds_ptr->edid); 147 num_modes = drm_add_edid_modes(connector, 148 ge_b850v3_lvds_ptr->edid); 149 } 150 151 return num_modes; 152 } 153 154 static enum drm_mode_status ge_b850v3_lvds_mode_valid( 155 struct drm_connector *connector, struct drm_display_mode *mode) 156 { 157 return MODE_OK; 158 } 159 160 static const struct 161 drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = { 162 .get_modes = ge_b850v3_lvds_get_modes, 163 .mode_valid = ge_b850v3_lvds_mode_valid, 164 }; 165 166 static enum drm_connector_status ge_b850v3_lvds_detect( 167 struct drm_connector *connector, bool force) 168 { 169 struct i2c_client *stdp4028_i2c = 170 ge_b850v3_lvds_ptr->stdp4028_i2c; 171 s32 link_state; 172 173 link_state = i2c_smbus_read_word_data(stdp4028_i2c, 174 STDP4028_DPTX_STS_REG); 175 176 if (link_state == STDP4028_CON_STATE_CONNECTED) 177 return connector_status_connected; 178 179 if (link_state == 0) 180 return connector_status_disconnected; 181 182 return connector_status_unknown; 183 } 184 185 static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = { 186 .fill_modes = drm_helper_probe_single_connector_modes, 187 .detect = ge_b850v3_lvds_detect, 188 .destroy = drm_connector_cleanup, 189 .reset = drm_atomic_helper_connector_reset, 190 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, 191 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, 192 }; 193 194 static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id) 195 { 196 struct i2c_client *stdp4028_i2c 197 = ge_b850v3_lvds_ptr->stdp4028_i2c; 198 199 i2c_smbus_write_word_data(stdp4028_i2c, 200 STDP4028_DPTX_IRQ_STS_REG, 201 STDP4028_DPTX_IRQ_CLEAR); 202 203 if (ge_b850v3_lvds_ptr->connector.dev) 204 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->connector.dev); 205 206 return IRQ_HANDLED; 207 } 208 209 static int ge_b850v3_lvds_attach(struct drm_bridge *bridge) 210 { 211 struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector; 212 struct i2c_client *stdp4028_i2c 213 = ge_b850v3_lvds_ptr->stdp4028_i2c; 214 int ret; 215 216 if (!bridge->encoder) { 217 DRM_ERROR("Parent encoder object not found"); 218 return -ENODEV; 219 } 220 221 connector->polled = DRM_CONNECTOR_POLL_HPD; 222 223 drm_connector_helper_add(connector, 224 &ge_b850v3_lvds_connector_helper_funcs); 225 226 ret = drm_connector_init(bridge->dev, connector, 227 &ge_b850v3_lvds_connector_funcs, 228 DRM_MODE_CONNECTOR_DisplayPort); 229 if (ret) { 230 DRM_ERROR("Failed to initialize connector with drm\n"); 231 return ret; 232 } 233 234 ret = drm_connector_attach_encoder(connector, bridge->encoder); 235 if (ret) 236 return ret; 237 238 /* Configures the bridge to re-enable interrupts after each ack. */ 239 i2c_smbus_write_word_data(stdp4028_i2c, 240 STDP4028_IRQ_OUT_CONF_REG, 241 STDP4028_DPTX_DP_IRQ_EN); 242 243 /* Enable interrupts */ 244 i2c_smbus_write_word_data(stdp4028_i2c, 245 STDP4028_DPTX_IRQ_EN_REG, 246 STDP4028_DPTX_IRQ_CONFIG); 247 248 return 0; 249 } 250 251 static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = { 252 .attach = ge_b850v3_lvds_attach, 253 }; 254 255 static int ge_b850v3_lvds_init(struct device *dev) 256 { 257 mutex_lock(&ge_b850v3_lvds_dev_mutex); 258 259 if (ge_b850v3_lvds_ptr) 260 goto success; 261 262 ge_b850v3_lvds_ptr = devm_kzalloc(dev, 263 sizeof(*ge_b850v3_lvds_ptr), 264 GFP_KERNEL); 265 266 if (!ge_b850v3_lvds_ptr) { 267 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 268 return -ENOMEM; 269 } 270 271 success: 272 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 273 return 0; 274 } 275 276 static void ge_b850v3_lvds_remove(void) 277 { 278 mutex_lock(&ge_b850v3_lvds_dev_mutex); 279 /* 280 * This check is to avoid both the drivers 281 * removing the bridge in their remove() function 282 */ 283 if (!ge_b850v3_lvds_ptr) 284 goto out; 285 286 drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge); 287 288 kfree(ge_b850v3_lvds_ptr->edid); 289 290 ge_b850v3_lvds_ptr = NULL; 291 out: 292 mutex_unlock(&ge_b850v3_lvds_dev_mutex); 293 } 294 295 static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c, 296 const struct i2c_device_id *id) 297 { 298 struct device *dev = &stdp4028_i2c->dev; 299 300 ge_b850v3_lvds_init(dev); 301 302 ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c; 303 i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr); 304 305 /* drm bridge initialization */ 306 ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs; 307 ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node; 308 drm_bridge_add(&ge_b850v3_lvds_ptr->bridge); 309 310 /* Clear pending interrupts since power up. */ 311 i2c_smbus_write_word_data(stdp4028_i2c, 312 STDP4028_DPTX_IRQ_STS_REG, 313 STDP4028_DPTX_IRQ_CLEAR); 314 315 if (!stdp4028_i2c->irq) 316 return 0; 317 318 return devm_request_threaded_irq(&stdp4028_i2c->dev, 319 stdp4028_i2c->irq, NULL, 320 ge_b850v3_lvds_irq_handler, 321 IRQF_TRIGGER_HIGH | IRQF_ONESHOT, 322 "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr); 323 } 324 325 static int stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c) 326 { 327 ge_b850v3_lvds_remove(); 328 329 return 0; 330 } 331 332 static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = { 333 {"stdp4028_ge_fw", 0}, 334 {}, 335 }; 336 MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table); 337 338 static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = { 339 { .compatible = "megachips,stdp4028-ge-b850v3-fw" }, 340 {}, 341 }; 342 MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match); 343 344 static struct i2c_driver stdp4028_ge_b850v3_fw_driver = { 345 .id_table = stdp4028_ge_b850v3_fw_i2c_table, 346 .probe = stdp4028_ge_b850v3_fw_probe, 347 .remove = stdp4028_ge_b850v3_fw_remove, 348 .driver = { 349 .name = "stdp4028-ge-b850v3-fw", 350 .of_match_table = stdp4028_ge_b850v3_fw_match, 351 }, 352 }; 353 354 static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c, 355 const struct i2c_device_id *id) 356 { 357 struct device *dev = &stdp2690_i2c->dev; 358 359 ge_b850v3_lvds_init(dev); 360 361 ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c; 362 i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr); 363 364 return 0; 365 } 366 367 static int stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c) 368 { 369 ge_b850v3_lvds_remove(); 370 371 return 0; 372 } 373 374 static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = { 375 {"stdp2690_ge_fw", 0}, 376 {}, 377 }; 378 MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table); 379 380 static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = { 381 { .compatible = "megachips,stdp2690-ge-b850v3-fw" }, 382 {}, 383 }; 384 MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match); 385 386 static struct i2c_driver stdp2690_ge_b850v3_fw_driver = { 387 .id_table = stdp2690_ge_b850v3_fw_i2c_table, 388 .probe = stdp2690_ge_b850v3_fw_probe, 389 .remove = stdp2690_ge_b850v3_fw_remove, 390 .driver = { 391 .name = "stdp2690-ge-b850v3-fw", 392 .of_match_table = stdp2690_ge_b850v3_fw_match, 393 }, 394 }; 395 396 static int __init stdpxxxx_ge_b850v3_init(void) 397 { 398 int ret; 399 400 ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver); 401 if (ret) 402 return ret; 403 404 return i2c_add_driver(&stdp2690_ge_b850v3_fw_driver); 405 } 406 module_init(stdpxxxx_ge_b850v3_init); 407 408 static void __exit stdpxxxx_ge_b850v3_exit(void) 409 { 410 i2c_del_driver(&stdp2690_ge_b850v3_fw_driver); 411 i2c_del_driver(&stdp4028_ge_b850v3_fw_driver); 412 } 413 module_exit(stdpxxxx_ge_b850v3_exit); 414 415 MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>"); 416 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>"); 417 MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)"); 418 MODULE_LICENSE("GPL v2"); 419