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

   1 /*
   2  * Driver for MegaChips STDP4028 with GE B850v3 firmware (LVDS-DP)
   3  * Driver for MegaChips STDP2690 with GE B850v3 firmware (DP-DP++)
   4
   5  * Copyright (c) 2017, Collabora Ltd.
   6  * Copyright (c) 2017, General Electric Company
   7
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms and conditions of the GNU General Public License,
  10  * version 2, as published by the Free Software Foundation.
  11
  12  * This program is distributed in the hope it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19
  20  * This driver creates a drm_bridge and a drm_connector for the LVDS to DP++
  21  * display bridge of the GE B850v3. There are two physical bridges on the video
  22  * signal pipeline: a STDP4028(LVDS to DP) and a STDP2690(DP to DP++). The
  23  * physical bridges are automatically configured by the input video signal, and
  24  * the driver has no access to the video processing pipeline. The driver is
  25  * only needed to read EDID from the STDP2690 and to handle HPD events from the
  26  * STDP4028. The driver communicates with both bridges over i2c. The video
  27  * signal pipeline is as follows:
  28  *
  29  *   Host -> LVDS|--(STDP4028)--|DP -> DP|--(STDP2690)--|DP++ -> Video output
  30  *
  31  */
  32
  33 #include <linux/gpio.h>
  34 #include <linux/i2c.h>
  35 #include <linux/module.h>
  36 #include <linux/of.h>
  37 #include <drm/drm_atomic.h>
  38 #include <drm/drm_atomic_helper.h>
  39 #include <drm/drm_crtc_helper.h>
  40 #include <drm/drm_edid.h>
  41 #include <drm/drmP.h>
  42
  43 #define EDID_EXT_BLOCK_CNT 0x7E
  44
  45 #define STDP4028_IRQ_OUT_CONF_REG 0x02
  46 #define STDP4028_DPTX_IRQ_EN_REG 0x3C
  47 #define STDP4028_DPTX_IRQ_STS_REG 0x3D
  48 #define STDP4028_DPTX_STS_REG 0x3E
  49
  50 #define STDP4028_DPTX_DP_IRQ_EN 0x1000
  51
  52 #define STDP4028_DPTX_HOTPLUG_IRQ_EN 0x0400
  53 #define STDP4028_DPTX_LINK_CH_IRQ_EN 0x2000
  54 #define STDP4028_DPTX_IRQ_CONFIG \
  55                 (STDP4028_DPTX_LINK_CH_IRQ_EN | STDP4028_DPTX_HOTPLUG_IRQ_EN)
  56
  57 #define STDP4028_DPTX_HOTPLUG_STS 0x0200
  58 #define STDP4028_DPTX_LINK_STS 0x1000
  59 #define STDP4028_CON_STATE_CONNECTED \
  60                 (STDP4028_DPTX_HOTPLUG_STS | STDP4028_DPTX_LINK_STS)
  61
  62 #define STDP4028_DPTX_HOTPLUG_CH_STS 0x0400
  63 #define STDP4028_DPTX_LINK_CH_STS 0x2000
  64 #define STDP4028_DPTX_IRQ_CLEAR \
  65                 (STDP4028_DPTX_LINK_CH_STS | STDP4028_DPTX_HOTPLUG_CH_STS)
  66
  67 static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex);
  68
  69 struct ge_b850v3_lvds {
  70         struct drm_connector connector;
  71         struct drm_bridge bridge;
  72         struct i2c_client *stdp4028_i2c;
  73         struct i2c_client *stdp2690_i2c;
  74         struct edid *edid;
  75 };
  76
  77 static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
  78
  79 static u8 *stdp2690_get_edid(struct i2c_client *client)
  80 {
  81         struct i2c_adapter *adapter = client->adapter;
  82         unsigned char start = 0x00;
  83         unsigned int total_size;
  84         u8 *block = kmalloc(EDID_LENGTH, GFP_KERNEL);
  85
  86         struct i2c_msg msgs[] = {
  87                 {
  88                         .addr   = client->addr,
  89                         .flags  = 0,
  90                         .len    = 1,
  91                         .buf    = &start,
  92                 }, {
  93                         .addr   = client->addr,
  94                         .flags  = I2C_M_RD,
  95                         .len    = EDID_LENGTH,
  96                         .buf    = block,
  97                 }
  98         };
  99
 100         if (!block)
 101                 return NULL;
 102
 103         if (i2c_transfer(adapter, msgs, 2) != 2) {
 104                 DRM_ERROR("Unable to read EDID.\n");
 105                 goto err;
 106         }
 107
 108         if (!drm_edid_block_valid(block, 0, false, NULL)) {
 109                 DRM_ERROR("Invalid EDID data\n");
 110                 goto err;
 111         }
 112
 113         total_size = (block[EDID_EXT_BLOCK_CNT] + 1) * EDID_LENGTH;
 114         if (total_size > EDID_LENGTH) {
 115                 kfree(block);
 116                 block = kmalloc(total_size, GFP_KERNEL);
 117                 if (!block)
 118                         return NULL;
 119
 120                 /* Yes, read the entire buffer, and do not skip the first
 121                  * EDID_LENGTH bytes.
 122                  */
 123                 start = 0x00;
 124                 msgs[1].len = total_size;
 125                 msgs[1].buf = block;
 126
 127                 if (i2c_transfer(adapter, msgs, 2) != 2) {
 128                         DRM_ERROR("Unable to read EDID extension blocks.\n");
 129                         goto err;
 130                 }
 131                 if (!drm_edid_block_valid(block, 1, false, NULL)) {
 132                         DRM_ERROR("Invalid EDID data\n");
 133                         goto err;
 134                 }
 135         }
 136
 137         return block;
 138
 139 err:
 140         kfree(block);
 141         return NULL;
 142 }
 143
 144 static int ge_b850v3_lvds_get_modes(struct drm_connector *connector)
 145 {
 146         struct i2c_client *client;
 147         int num_modes = 0;
 148
 149         client = ge_b850v3_lvds_ptr->stdp2690_i2c;
 150
 151         kfree(ge_b850v3_lvds_ptr->edid);
 152         ge_b850v3_lvds_ptr->edid = (struct edid *)stdp2690_get_edid(client);
 153
 154         if (ge_b850v3_lvds_ptr->edid) {
 155                 drm_mode_connector_update_edid_property(connector,
 156                                                       ge_b850v3_lvds_ptr->edid);
 157                 num_modes = drm_add_edid_modes(connector,
 158                                                ge_b850v3_lvds_ptr->edid);
 159         }
 160
 161         return num_modes;
 162 }
 163
 164 static enum drm_mode_status ge_b850v3_lvds_mode_valid(
 165                 struct drm_connector *connector, struct drm_display_mode *mode)
 166 {
 167         return MODE_OK;
 168 }
 169
 170 static const struct
 171 drm_connector_helper_funcs ge_b850v3_lvds_connector_helper_funcs = {
 172         .get_modes = ge_b850v3_lvds_get_modes,
 173         .mode_valid = ge_b850v3_lvds_mode_valid,
 174 };
 175
 176 static enum drm_connector_status ge_b850v3_lvds_detect(
 177                 struct drm_connector *connector, bool force)
 178 {
 179         struct i2c_client *stdp4028_i2c =
 180                         ge_b850v3_lvds_ptr->stdp4028_i2c;
 181         s32 link_state;
 182
 183         link_state = i2c_smbus_read_word_data(stdp4028_i2c,
 184                                               STDP4028_DPTX_STS_REG);
 185
 186         if (link_state == STDP4028_CON_STATE_CONNECTED)
 187                 return connector_status_connected;
 188
 189         if (link_state == 0)
 190                 return connector_status_disconnected;
 191
 192         return connector_status_unknown;
 193 }
 194
 195 static const struct drm_connector_funcs ge_b850v3_lvds_connector_funcs = {
 196         .fill_modes = drm_helper_probe_single_connector_modes,
 197         .detect = ge_b850v3_lvds_detect,
 198         .destroy = drm_connector_cleanup,
 199         .reset = drm_atomic_helper_connector_reset,
 200         .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
 201         .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 202 };
 203
 204 static irqreturn_t ge_b850v3_lvds_irq_handler(int irq, void *dev_id)
 205 {
 206         struct i2c_client *stdp4028_i2c
 207                         = ge_b850v3_lvds_ptr->stdp4028_i2c;
 208
 209         i2c_smbus_write_word_data(stdp4028_i2c,
 210                                   STDP4028_DPTX_IRQ_STS_REG,
 211                                   STDP4028_DPTX_IRQ_CLEAR);
 212
 213         if (ge_b850v3_lvds_ptr->connector.dev)
 214                 drm_kms_helper_hotplug_event(ge_b850v3_lvds_ptr->connector.dev);
 215
 216         return IRQ_HANDLED;
 217 }
 218
 219 static int ge_b850v3_lvds_attach(struct drm_bridge *bridge)
 220 {
 221         struct drm_connector *connector = &ge_b850v3_lvds_ptr->connector;
 222         struct i2c_client *stdp4028_i2c
 223                         = ge_b850v3_lvds_ptr->stdp4028_i2c;
 224         int ret;
 225
 226         if (!bridge->encoder) {
 227                 DRM_ERROR("Parent encoder object not found");
 228                 return -ENODEV;
 229         }
 230
 231         connector->polled = DRM_CONNECTOR_POLL_HPD;
 232
 233         drm_connector_helper_add(connector,
 234                                  &ge_b850v3_lvds_connector_helper_funcs);
 235
 236         ret = drm_connector_init(bridge->dev, connector,
 237                                  &ge_b850v3_lvds_connector_funcs,
 238                                  DRM_MODE_CONNECTOR_DisplayPort);
 239         if (ret) {
 240                 DRM_ERROR("Failed to initialize connector with drm\n");
 241                 return ret;
 242         }
 243
 244         ret = drm_mode_connector_attach_encoder(connector, bridge->encoder);
 245         if (ret)
 246                 return ret;
 247
 248         /* Configures the bridge to re-enable interrupts after each ack. */
 249         i2c_smbus_write_word_data(stdp4028_i2c,
 250                                   STDP4028_IRQ_OUT_CONF_REG,
 251                                   STDP4028_DPTX_DP_IRQ_EN);
 252
 253         /* Enable interrupts */
 254         i2c_smbus_write_word_data(stdp4028_i2c,
 255                                   STDP4028_DPTX_IRQ_EN_REG,
 256                                   STDP4028_DPTX_IRQ_CONFIG);
 257
 258         return 0;
 259 }
 260
 261 static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
 262         .attach = ge_b850v3_lvds_attach,
 263 };
 264
 265 static int ge_b850v3_lvds_init(struct device *dev)
 266 {
 267         mutex_lock(&ge_b850v3_lvds_dev_mutex);
 268
 269         if (ge_b850v3_lvds_ptr)
 270                 goto success;
 271
 272         ge_b850v3_lvds_ptr = devm_kzalloc(dev,
 273                                           sizeof(*ge_b850v3_lvds_ptr),
 274                                           GFP_KERNEL);
 275
 276         if (!ge_b850v3_lvds_ptr) {
 277                 mutex_unlock(&ge_b850v3_lvds_dev_mutex);
 278                 return -ENOMEM;
 279         }
 280
 281 success:
 282         mutex_unlock(&ge_b850v3_lvds_dev_mutex);
 283         return 0;
 284 }
 285
 286 static void ge_b850v3_lvds_remove(void)
 287 {
 288         mutex_lock(&ge_b850v3_lvds_dev_mutex);
 289         /*
 290          * This check is to avoid both the drivers
 291          * removing the bridge in their remove() function
 292          */
 293         if (!ge_b850v3_lvds_ptr)
 294                 goto out;
 295
 296         drm_bridge_remove(&ge_b850v3_lvds_ptr->bridge);
 297
 298         kfree(ge_b850v3_lvds_ptr->edid);
 299
 300         ge_b850v3_lvds_ptr = NULL;
 301 out:
 302         mutex_unlock(&ge_b850v3_lvds_dev_mutex);
 303 }
 304
 305 static int stdp4028_ge_b850v3_fw_probe(struct i2c_client *stdp4028_i2c,
 306                                        const struct i2c_device_id *id)
 307 {
 308         struct device *dev = &stdp4028_i2c->dev;
 309
 310         ge_b850v3_lvds_init(dev);
 311
 312         ge_b850v3_lvds_ptr->stdp4028_i2c = stdp4028_i2c;
 313         i2c_set_clientdata(stdp4028_i2c, ge_b850v3_lvds_ptr);
 314
 315         /* drm bridge initialization */
 316         ge_b850v3_lvds_ptr->bridge.funcs = &ge_b850v3_lvds_funcs;
 317         ge_b850v3_lvds_ptr->bridge.of_node = dev->of_node;
 318         drm_bridge_add(&ge_b850v3_lvds_ptr->bridge);
 319
 320         /* Clear pending interrupts since power up. */
 321         i2c_smbus_write_word_data(stdp4028_i2c,
 322                                   STDP4028_DPTX_IRQ_STS_REG,
 323                                   STDP4028_DPTX_IRQ_CLEAR);
 324
 325         if (!stdp4028_i2c->irq)
 326                 return 0;
 327
 328         return devm_request_threaded_irq(&stdp4028_i2c->dev,
 329                         stdp4028_i2c->irq, NULL,
 330                         ge_b850v3_lvds_irq_handler,
 331                         IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
 332                         "ge-b850v3-lvds-dp", ge_b850v3_lvds_ptr);
 333 }
 334
 335 static int stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
 336 {
 337         ge_b850v3_lvds_remove();
 338
 339         return 0;
 340 }
 341
 342 static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
 343         {"stdp4028_ge_fw", 0},
 344         {},
 345 };
 346 MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
 347
 348 static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
 349         { .compatible = "megachips,stdp4028-ge-b850v3-fw" },
 350         {},
 351 };
 352 MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
 353
 354 static struct i2c_driver stdp4028_ge_b850v3_fw_driver = {
 355         .id_table       = stdp4028_ge_b850v3_fw_i2c_table,
 356         .probe          = stdp4028_ge_b850v3_fw_probe,
 357         .remove         = stdp4028_ge_b850v3_fw_remove,
 358         .driver         = {
 359                 .name           = "stdp4028-ge-b850v3-fw",
 360                 .of_match_table = stdp4028_ge_b850v3_fw_match,
 361         },
 362 };
 363
 364 static int stdp2690_ge_b850v3_fw_probe(struct i2c_client *stdp2690_i2c,
 365                                        const struct i2c_device_id *id)
 366 {
 367         struct device *dev = &stdp2690_i2c->dev;
 368
 369         ge_b850v3_lvds_init(dev);
 370
 371         ge_b850v3_lvds_ptr->stdp2690_i2c = stdp2690_i2c;
 372         i2c_set_clientdata(stdp2690_i2c, ge_b850v3_lvds_ptr);
 373
 374         return 0;
 375 }
 376
 377 static int stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
 378 {
 379         ge_b850v3_lvds_remove();
 380
 381         return 0;
 382 }
 383
 384 static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
 385         {"stdp2690_ge_fw", 0},
 386         {},
 387 };
 388 MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
 389
 390 static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
 391         { .compatible = "megachips,stdp2690-ge-b850v3-fw" },
 392         {},
 393 };
 394 MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
 395
 396 static struct i2c_driver stdp2690_ge_b850v3_fw_driver = {
 397         .id_table       = stdp2690_ge_b850v3_fw_i2c_table,
 398         .probe          = stdp2690_ge_b850v3_fw_probe,
 399         .remove         = stdp2690_ge_b850v3_fw_remove,
 400         .driver         = {
 401                 .name           = "stdp2690-ge-b850v3-fw",
 402                 .of_match_table = stdp2690_ge_b850v3_fw_match,
 403         },
 404 };
 405
 406 static int __init stdpxxxx_ge_b850v3_init(void)
 407 {
 408         int ret;
 409
 410         ret = i2c_add_driver(&stdp4028_ge_b850v3_fw_driver);
 411         if (ret)
 412                 return ret;
 413
 414         return i2c_add_driver(&stdp2690_ge_b850v3_fw_driver);
 415 }
 416 module_init(stdpxxxx_ge_b850v3_init);
 417
 418 static void __exit stdpxxxx_ge_b850v3_exit(void)
 419 {
 420         i2c_del_driver(&stdp2690_ge_b850v3_fw_driver);
 421         i2c_del_driver(&stdp4028_ge_b850v3_fw_driver);
 422 }
 423 module_exit(stdpxxxx_ge_b850v3_exit);
 424
 425 MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");
 426 MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");
 427 MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
 428 MODULE_LICENSE("GPL v2");