linux/drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
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   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_edid.h>
  40#include <drm/drm_probe_helper.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
  67static DEFINE_MUTEX(ge_b850v3_lvds_dev_mutex);
  68
  69struct 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
  77static struct ge_b850v3_lvds *ge_b850v3_lvds_ptr;
  78
  79static 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
 139err:
 140        kfree(block);
 141        return NULL;
 142}
 143
 144static 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_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
 164static 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
 170static const struct
 171drm_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
 176static 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
 195static 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
 204static 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
 219static 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_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
 261static const struct drm_bridge_funcs ge_b850v3_lvds_funcs = {
 262        .attach = ge_b850v3_lvds_attach,
 263};
 264
 265static 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
 281success:
 282        mutex_unlock(&ge_b850v3_lvds_dev_mutex);
 283        return 0;
 284}
 285
 286static 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;
 301out:
 302        mutex_unlock(&ge_b850v3_lvds_dev_mutex);
 303}
 304
 305static 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
 335static int stdp4028_ge_b850v3_fw_remove(struct i2c_client *stdp4028_i2c)
 336{
 337        ge_b850v3_lvds_remove();
 338
 339        return 0;
 340}
 341
 342static const struct i2c_device_id stdp4028_ge_b850v3_fw_i2c_table[] = {
 343        {"stdp4028_ge_fw", 0},
 344        {},
 345};
 346MODULE_DEVICE_TABLE(i2c, stdp4028_ge_b850v3_fw_i2c_table);
 347
 348static const struct of_device_id stdp4028_ge_b850v3_fw_match[] = {
 349        { .compatible = "megachips,stdp4028-ge-b850v3-fw" },
 350        {},
 351};
 352MODULE_DEVICE_TABLE(of, stdp4028_ge_b850v3_fw_match);
 353
 354static 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
 364static 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
 377static int stdp2690_ge_b850v3_fw_remove(struct i2c_client *stdp2690_i2c)
 378{
 379        ge_b850v3_lvds_remove();
 380
 381        return 0;
 382}
 383
 384static const struct i2c_device_id stdp2690_ge_b850v3_fw_i2c_table[] = {
 385        {"stdp2690_ge_fw", 0},
 386        {},
 387};
 388MODULE_DEVICE_TABLE(i2c, stdp2690_ge_b850v3_fw_i2c_table);
 389
 390static const struct of_device_id stdp2690_ge_b850v3_fw_match[] = {
 391        { .compatible = "megachips,stdp2690-ge-b850v3-fw" },
 392        {},
 393};
 394MODULE_DEVICE_TABLE(of, stdp2690_ge_b850v3_fw_match);
 395
 396static 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
 406static 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}
 416module_init(stdpxxxx_ge_b850v3_init);
 417
 418static 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}
 423module_exit(stdpxxxx_ge_b850v3_exit);
 424
 425MODULE_AUTHOR("Peter Senna Tschudin <peter.senna@collabora.com>");
 426MODULE_AUTHOR("Martyn Welch <martyn.welch@collabora.co.uk>");
 427MODULE_DESCRIPTION("GE LVDS to DP++ display bridge)");
 428MODULE_LICENSE("GPL v2");
 429