drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c

   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 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 struct edid *ge_b850v3_lvds_get_edid(struct drm_bridge *bridge,
 134                                             struct drm_connector *connector)
 135 {
 136         struct i2c_client *client;
 137
 138         client = ge_b850v3_lvds_ptr->stdp2690_i2c;
 139
 140         return (struct edid *)stdp2690_get_edid(client);
 141 }
 142
 143 static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
 144 {
 145         struct edid *edid;
 146         int num_modes;
 147
 148         edid = ge_b850v3_lvds_get_edid(&ge_b850v3_lvds_ptr->bridge, connector);
 149
 150         drm_connector_update_edid_property(connector, edid);
 151         num_modes = drm_add_edid_modes(connector, edid);
 152         kfree(edid);
 153
 154         return num_modes;
 155 }
 156
 157 static enum drm_mode_status ge_b850v3_lvds_mode_valid(
 158                 struct drm_connector *connector, struct drm_display_mode *mode)
 159 {
 160         return MODE_OK;
 161 }
 162
 163 static const struct
 164 drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {
 165         .get_modes = ge_b850v3_lvds_get_modes,
 166         .mode_valid = ge_b850v3_lvds_mode_valid,
 167 };
 168
 169 static enum drm_connector_status ge_b850v3_lvds_bridge_detect(struct drm_bridge *bridge)
 170 {
 171         struct i2c_client *stdp4028_i2c =
 172                         ge_b850v3_lvds_ptr->stdp4028_i2c;
 173         s32 link_state;
 174
 175         link_state = i2c_smbus_read_word_data(stdp4028_i2c,
 176                                               STDP4028_DPTX_STS_REG);
 177
 178         if (link_state == STDP4028_CON_STATE_CONNECTED)
 179                 return connector_status_connected;
 180
 181         if (link_state == 0)
 182                 return connector_status_disconnected;
 183
 184         return connector_status_unknown;
 185 }
 186
 187 static enum drm_connector_status ge_b850v3_lvds_detect(struct drm_connector *connector,
 188                                                        bool force)
 189 {
 190         return ge_b850v3_lvds_bridge_detect(&ge_b850v3_lvds_ptr->bridge);
 191 }
 192
 193 static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {
 194         .fill_modes = drm_helper_probe_single_connector_modes,
 195         .detect = ge_b850v3_lvds_detect,
 196         .destroy = drm_connector_cleanup,
 197         .reset = drm_atomic_helper_connector_reset,
 198         .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 199         .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 200 };
 201
 202 static int ge_b850v3_lvds_create_connector(struct drm_bridge *bridge)
 203 {
 204         struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;
 205         int ret;
 206
 207         if (!bridge->encoder) {
 208                 DRM_ERROR("Parent encoder object not found");
 209                 return -ENODEV;
 210         }
 211
 212         connector->polled = DRM_CONNECTOR_POLL_HPD;
 213
 214         drm_connector_helper_add(connector,
 215                                  &ge_b850v3_lvds_connector_helper_funcs);
 216
 217         ret = drm_connector_init(bridge->dev, connector,
 218                                  &ge_b850v3_lvds_connector_funcs,
 219                                  DRM_MODE_CONNECTOR_DisplayPort);
 220         if (ret) {
 221                 DRM_ERROR("Failed to initialize connector with drm\n");
 222                 return ret;
 223         }
 224
 225         return drm_connector_attach_encoder(connector, bridge->encoder);
 226 }
 227
 228 static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)
 229 {
 230         struct i2c_client *stdp4028_i2c
 231                         = ge_b850v3_lvds_ptr->stdp4028_i2c;
 232
 233         i2c_smbus_write_word_data(stdp4028_i2c,
 234                                   STDP4028_DPTX_IRQ_STS_REG,
 235                                   STDP4028_DPTX_IRQ_CLEAR);
 236
 237         if (ge_b850v3_lvds_ptr->bridge.dev)
 238                 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->bridge.dev);
 239
 240         return IRQ_HANDLED;
 241 }
 242
 243 static int ge_b850v3_lvds_attach(struct drm_bridge *bridge,
 244                                  enum drm_bridge_attach_flags flags)
 245 {
 246         struct i2c_client *stdp4028_i2c
 247                         = ge_b850v3_lvds_ptr->stdp4028_i2c;
 248
 249         /* Configures the bridge to re-enable interrupts after each ack. */
 250         i2c_smbus_write_word_data(stdp4028_i2c,
 251                                   STDP4028_IRQ_OUT_CONF_REG,
 252                                   STDP4028_DPTX_DP_IRQ_EN);
 253
 254         /* Enable interrupts */
 255         i2c_smbus_write_word_data(stdp4028_i2c,
 256                                   STDP4028_DPTX_IRQ_EN_REG,
 257                                   STDP4028_DPTX_IRQ_CONFIG);
 258
 259         if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
 260                 return 0;
 261
 262         return ge_b850v3_lvds_create_connector(bridge);
 263 }
 264
 265 static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
 266         .attach = ge_b850v3_lvds_attach,
 267         .detect = ge_b850v3_lvds_bridge_detect,
 268         .get_edid = ge_b850v3_lvds_get_edid,
 269 };
 270
 271 static int ge_b850v3_lvds_init(struct device *dev)
 272 {
 273         mutex_lock(&ge_b850v3_lvds_dev_mutex);
 274
 275         if (ge_b850v3_lvds_ptr)
 276                 goto success;
 277
 278         ge_b850v3_lvds_ptr = devm_kzalloc(dev,
 279                                           sizeof(*ge_b850v3_lvds_ptr),
 280                                           GFP_KERNEL);
 281
 282         if (!ge_b850v3_lvds_ptr) {
 283                 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
 284                 return -ENOMEM;
 285         }
 286
 287 success:
 288         mutex_unlock(&ge_b850v3_lvds_dev_mutex);
 289         return 0;
 290 }
 291
 292 static void ge_b850v3_lvds_remove(void)
 293 {
 294         mutex_lock(&ge_b850v3_lvds_dev_mutex);
 295         /*
 296          * This check is to avoid both the drivers
 297          * removing the bridge in their remove() function
 298          */
 299         if (!ge_b850v3_lvds_ptr)
 300                 goto out;
 301
 302         drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
 303
 304         ge_b850v3_lvds_ptr = NULL;
 305 out:
 306         mutex_unlock(&ge_b850v3_lvds_dev_mutex);
 307 }
 308
 309 static int ge_b850v3_register(void)
 310 {
 311         struct i2c_client *stdp4028_i2c = ge_b850v3_lvds_ptr->stdp4028_i2c;
 312         struct device *dev = &stdp4028_i2c->dev;
 313
 314         /* drm bridge initialization */
 315         ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;
 316         ge_b850v3_lvds_ptr->bridge.ops = DRM_BRIDGE_OP_DETECT |
 317                                          DRM_BRIDGE_OP_EDID;
 318         ge_b850v3_lvds_ptr->bridge.type = DRM_MODE_CONNECTOR_DisplayPort;
 319         ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
 320         drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);
 321
 322         /* Clear pending interrupts since power up. */
 323         i2c_smbus_write_word_data(stdp4028_i2c,
 324                                   STDP4028_DPTX_IRQ_STS_REG,
 325                                   STDP4028_DPTX_IRQ_CLEAR);
 326
 327         if (!stdp4028_i2c->irq)
 328                 return 0;
 329
 330         return devm_request_threaded_irq(&stdp4028_i2c->dev,
 331                         stdp4028_i2c->irq, NULL,
 332                         ge_b850v3_lvds_irq_handler,
 333                         IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
 334                         "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
 335 }
 336
 337 static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c,
 338                                        const struct i2c_device_id *id)
 339 {
 340         struct device *dev = &stdp4028_i2c->dev;
 341         int ret;
 342
 343         ret = ge_b850v3_lvds_init(dev);
 344
 345         if (ret)
 346                 return ret;
 347
 348         ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
 349         i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
 350
 351         /* Only register after both bridges are probed */
 352         if (!ge_b850v3_lvds_ptr->stdp2690_i2c)
 353                 return 0;
 354
 355         return ge_b850v3_register();
 356 }
 357
 358 static int stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
 359 {
 360         ge_b850v3_lvds_remove();
 361
 362         return 0;
 363 }
 364
 365 static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
 366         {"stdp4028_ge_fw", 0},
 367         {},
 368 };
 369 MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
 370
 371 static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
 372         { .compatible = "megachips,stdp4028-ge-b850v3-fw" },
 373         {},
 374 };
 375 MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
 376
 377 static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {
 378         .id_table       = stdp4028_ge_b850v3_fw_i2c_table,
 379         .probe          = stdp4028_ge_b850v3_fw_probe,
 380         .remove         = stdp4028_ge_b850v3_fw_remove,
 381         .driver         = {
 382                 .name           = "stdp4028-ge-b850v3-fw",
 383                 .of_match_table = stdp4028_ge_b850v3_fw_match,
 384         },
 385 };
 386
 387 static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c,
 388                                        const struct i2c_device_id *id)
 389 {
 390         struct device *dev = &stdp2690_i2c->dev;
 391         int ret;
 392
 393         ret = ge_b850v3_lvds_init(dev);
 394
 395         if (ret)
 396                 return ret;
 397
 398         ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
 399         i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
 400
 401         /* Only register after both bridges are probed */
 402         if (!ge_b850v3_lvds_ptr->stdp4028_i2c)
 403                 return 0;
 404
 405         return ge_b850v3_register();
 406 }
 407
 408 static int stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
 409 {
 410         ge_b850v3_lvds_remove();
 411
 412         return 0;
 413 }
 414
 415 static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
 416         {"stdp2690_ge_fw", 0},
 417         {},
 418 };
 419 MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
 420
 421 static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
 422         { .compatible = "megachips,stdp2690-ge-b850v3-fw" },
 423         {},
 424 };
 425 MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
 426
 427 static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {
 428         .id_table       = stdp2690_ge_b850v3_fw_i2c_table,
 429         .probe          = stdp2690_ge_b850v3_fw_probe,
 430         .remove         = stdp2690_ge_b850v3_fw_remove,
 431         .driver         = {
 432                 .name           = "stdp2690-ge-b850v3-fw",
 433                 .of_match_table = stdp2690_ge_b850v3_fw_match,
 434         },
 435 };
 436
 437 static int __init stdpxxxx_ge_b850v3_init(void)
 438 {
 439         int ret;
 440
 441         ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);
 442         if (ret)
 443                 return ret;
 444
 445         return i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
 446 }
 447 module_init(stdpxxxx_ge_b850v3_init);
 448
 449 static void __exit stdpxxxx_ge_b850v3_exit(void)
 450 {
 451         i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);
 452         i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
 453 }
 454 module_exit(stdpxxxx_ge_b850v3_exit);
 455
 456 MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");
 457 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");
 458 MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
 459 MODULE_LICENSE("GPL v2");