drivers/gpu/drm/i2c/tda9950.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  TDA9950 Consumer Electronics Control driver
   4  *
   5  * The NXP TDA9950 implements the HDMI Consumer Electronics Control
   6  * interface.  The host interface is similar to a mailbox: the data
   7  * registers starting at REG_CDR0 are written to send a command to the
   8  * internal CPU, and replies are read from these registers.
   9  *
  10  * As the data registers represent a mailbox, they must be accessed
  11  * as a single I2C transaction.  See the TDA9950 data sheet for details.
  12  */
  13 #include <linux/delay.h>
  14 #include <linux/i2c.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_data/tda9950.h>
  18 #include <linux/slab.h>
  19 #include <drm/drm_edid.h>
  20 #include <media/cec.h>
  21 #include <media/cec-notifier.h>
  22
  23 enum {
  24         REG_CSR = 0x00,
  25         CSR_BUSY = BIT(7),
  26         CSR_INT  = BIT(6),
  27         CSR_ERR  = BIT(5),
  28
  29         REG_CER = 0x01,
  30
  31         REG_CVR = 0x02,
  32
  33         REG_CCR = 0x03,
  34         CCR_RESET = BIT(7),
  35         CCR_ON    = BIT(6),
  36
  37         REG_ACKH = 0x04,
  38         REG_ACKL = 0x05,
  39
  40         REG_CCONR = 0x06,
  41         CCONR_ENABLE_ERROR = BIT(4),
  42         CCONR_RETRY_MASK = 7,
  43
  44         REG_CDR0 = 0x07,
  45
  46         CDR1_REQ = 0x00,
  47         CDR1_CNF = 0x01,
  48         CDR1_IND = 0x81,
  49         CDR1_ERR = 0x82,
  50         CDR1_IER = 0x83,
  51
  52         CDR2_CNF_SUCCESS    = 0x00,
  53         CDR2_CNF_OFF_STATE  = 0x80,
  54         CDR2_CNF_BAD_REQ    = 0x81,
  55         CDR2_CNF_CEC_ACCESS = 0x82,
  56         CDR2_CNF_ARB_ERROR  = 0x83,
  57         CDR2_CNF_BAD_TIMING = 0x84,
  58         CDR2_CNF_NACK_ADDR  = 0x85,
  59         CDR2_CNF_NACK_DATA  = 0x86,
  60 };
  61
  62 struct tda9950_priv {
  63         struct i2c_client *client;
  64         struct device *hdmi;
  65         struct cec_adapter *adap;
  66         struct tda9950_glue *glue;
  67         u16 addresses;
  68         struct cec_msg rx_msg;
  69         struct cec_notifier *notify;
  70         bool open;
  71 };
  72
  73 static int tda9950_write_range(struct i2c_client *client, u8 addr, u8 *p, int cnt)
  74 {
  75         struct i2c_msg msg;
  76         u8 buf[CEC_MAX_MSG_SIZE + 3];
  77         int ret;
  78
  79         if (WARN_ON(cnt > sizeof(buf) - 1))
  80                 return -EINVAL;
  81
  82         buf[0] = addr;
  83         memcpy(buf + 1, p, cnt);
  84
  85         msg.addr = client->addr;
  86         msg.flags = 0;
  87         msg.len = cnt + 1;
  88         msg.buf = buf;
  89
  90         dev_dbg(&client->dev, "wr 0x%02x: %*ph\n", addr, cnt, p);
  91
  92         ret = i2c_transfer(client->adapter, &msg, 1);
  93         if (ret < 0)
  94                 dev_err(&client->dev, "Error %d writing to cec:0x%x\n", ret, addr);
  95         return ret < 0 ? ret : 0;
  96 }
  97
  98 static void tda9950_write(struct i2c_client *client, u8 addr, u8 val)
  99 {
 100         tda9950_write_range(client, addr, &val, 1);
 101 }
 102
 103 static int tda9950_read_range(struct i2c_client *client, u8 addr, u8 *p, int cnt)
 104 {
 105         struct i2c_msg msg[2];
 106         int ret;
 107
 108         msg[0].addr = client->addr;
 109         msg[0].flags = 0;
 110         msg[0].len = 1;
 111         msg[0].buf = &addr;
 112         msg[1].addr = client->addr;
 113         msg[1].flags = I2C_M_RD;
 114         msg[1].len = cnt;
 115         msg[1].buf = p;
 116
 117         ret = i2c_transfer(client->adapter, msg, 2);
 118         if (ret < 0)
 119                 dev_err(&client->dev, "Error %d reading from cec:0x%x\n", ret, addr);
 120
 121         dev_dbg(&client->dev, "rd 0x%02x: %*ph\n", addr, cnt, p);
 122
 123         return ret;
 124 }
 125
 126 static u8 tda9950_read(struct i2c_client *client, u8 addr)
 127 {
 128         int ret;
 129         u8 val;
 130
 131         ret = tda9950_read_range(client, addr, &val, 1);
 132         if (ret < 0)
 133                 val = 0;
 134
 135         return val;
 136 }
 137
 138 static irqreturn_t tda9950_irq(int irq, void *data)
 139 {
 140         struct tda9950_priv *priv = data;
 141         unsigned int tx_status;
 142         u8 csr, cconr, buf[19];
 143         u8 arb_lost_cnt, nack_cnt, err_cnt;
 144
 145         if (!priv->open)
 146                 return IRQ_NONE;
 147
 148         csr = tda9950_read(priv->client, REG_CSR);
 149         if (!(csr & CSR_INT))
 150                 return IRQ_NONE;
 151
 152         cconr = tda9950_read(priv->client, REG_CCONR) & CCONR_RETRY_MASK;
 153
 154         tda9950_read_range(priv->client, REG_CDR0, buf, sizeof(buf));
 155
 156         /*
 157          * This should never happen: the data sheet says that there will
 158          * always be a valid message if the interrupt line is asserted.
 159          */
 160         if (buf[0] == 0) {
 161                 dev_warn(&priv->client->dev, "interrupt pending, but no message?\n");
 162                 return IRQ_NONE;
 163         }
 164
 165         switch (buf[1]) {
 166         case CDR1_CNF: /* transmit result */
 167                 arb_lost_cnt = nack_cnt = err_cnt = 0;
 168                 switch (buf[2]) {
 169                 case CDR2_CNF_SUCCESS:
 170                         tx_status = CEC_TX_STATUS_OK;
 171                         break;
 172
 173                 case CDR2_CNF_ARB_ERROR:
 174                         tx_status = CEC_TX_STATUS_ARB_LOST;
 175                         arb_lost_cnt = cconr;
 176                         break;
 177
 178                 case CDR2_CNF_NACK_ADDR:
 179                         tx_status = CEC_TX_STATUS_NACK;
 180                         nack_cnt = cconr;
 181                         break;
 182
 183                 default: /* some other error, refer to TDA9950 docs */
 184                         dev_err(&priv->client->dev, "CNF reply error 0x%02x\n",
 185                                 buf[2]);
 186                         tx_status = CEC_TX_STATUS_ERROR;
 187                         err_cnt = cconr;
 188                         break;
 189                 }
 190                 /* TDA9950 executes all retries for us */
 191                 if (tx_status != CEC_TX_STATUS_OK)
 192                         tx_status |= CEC_TX_STATUS_MAX_RETRIES;
 193                 cec_transmit_done(priv->adap, tx_status, arb_lost_cnt,
 194                                   nack_cnt, 0, err_cnt);
 195                 break;
 196
 197         case CDR1_IND:
 198                 priv->rx_msg.len = buf[0] - 2;
 199                 if (priv->rx_msg.len > CEC_MAX_MSG_SIZE)
 200                         priv->rx_msg.len = CEC_MAX_MSG_SIZE;
 201
 202                 memcpy(priv->rx_msg.msg, buf + 2, priv->rx_msg.len);
 203                 cec_received_msg(priv->adap, &priv->rx_msg);
 204                 break;
 205
 206         default: /* unknown */
 207                 dev_err(&priv->client->dev, "unknown service id 0x%02x\n",
 208                         buf[1]);
 209                 break;
 210         }
 211
 212         return IRQ_HANDLED;
 213 }
 214
 215 static int tda9950_cec_transmit(struct cec_adapter *adap, u8 attempts,
 216                                 u32 signal_free_time, struct cec_msg *msg)
 217 {
 218         struct tda9950_priv *priv = adap->priv;
 219         u8 buf[CEC_MAX_MSG_SIZE + 2];
 220
 221         buf[0] = 2 + msg->len;
 222         buf[1] = CDR1_REQ;
 223         memcpy(buf + 2, msg->msg, msg->len);
 224
 225         if (attempts > 5)
 226                 attempts = 5;
 227
 228         tda9950_write(priv->client, REG_CCONR, attempts);
 229
 230         return tda9950_write_range(priv->client, REG_CDR0, buf, 2 + msg->len);
 231 }
 232
 233 static int tda9950_cec_adap_log_addr(struct cec_adapter *adap, u8 addr)
 234 {
 235         struct tda9950_priv *priv = adap->priv;
 236         u16 addresses;
 237         u8 buf[2];
 238
 239         if (addr == CEC_LOG_ADDR_INVALID)
 240                 addresses = priv->addresses = 0;
 241         else
 242                 addresses = priv->addresses |= BIT(addr);
 243
 244         /* TDA9950 doesn't want address 15 set */
 245         addresses &= 0x7fff;
 246         buf[0] = addresses >> 8;
 247         buf[1] = addresses;
 248
 249         return tda9950_write_range(priv->client, REG_ACKH, buf, 2);
 250 }
 251
 252 /*
 253  * When operating as part of the TDA998x, we need additional handling
 254  * to initialise and shut down the TDA9950 part of the device.  These
 255  * two hooks are provided to allow the TDA998x code to perform those
 256  * activities.
 257  */
 258 static int tda9950_glue_open(struct tda9950_priv *priv)
 259 {
 260         int ret = 0;
 261
 262         if (priv->glue && priv->glue->open)
 263                 ret = priv->glue->open(priv->glue->data);
 264
 265         priv->open = true;
 266
 267         return ret;
 268 }
 269
 270 static void tda9950_glue_release(struct tda9950_priv *priv)
 271 {
 272         priv->open = false;
 273
 274         if (priv->glue && priv->glue->release)
 275                 priv->glue->release(priv->glue->data);
 276 }
 277
 278 static int tda9950_open(struct tda9950_priv *priv)
 279 {
 280         struct i2c_client *client = priv->client;
 281         int ret;
 282
 283         ret = tda9950_glue_open(priv);
 284         if (ret)
 285                 return ret;
 286
 287         /* Reset the TDA9950, and wait 250ms for it to recover */
 288         tda9950_write(client, REG_CCR, CCR_RESET);
 289         msleep(250);
 290
 291         tda9950_cec_adap_log_addr(priv->adap, CEC_LOG_ADDR_INVALID);
 292
 293         /* Start the command processor */
 294         tda9950_write(client, REG_CCR, CCR_ON);
 295
 296         return 0;
 297 }
 298
 299 static void tda9950_release(struct tda9950_priv *priv)
 300 {
 301         struct i2c_client *client = priv->client;
 302         int timeout = 50;
 303         u8 csr;
 304
 305         /* Stop the command processor */
 306         tda9950_write(client, REG_CCR, 0);
 307
 308         /* Wait up to .5s for it to signal non-busy */
 309         do {
 310                 csr = tda9950_read(client, REG_CSR);
 311                 if (!(csr & CSR_BUSY) || !--timeout)
 312                         break;
 313                 msleep(10);
 314         } while (1);
 315
 316         /* Warn the user that their IRQ may die if it's shared. */
 317         if (csr & CSR_BUSY)
 318                 dev_warn(&client->dev, "command processor failed to stop, irq%d may die (csr=0x%02x)\n",
 319                          client->irq, csr);
 320
 321         tda9950_glue_release(priv);
 322 }
 323
 324 static int tda9950_cec_adap_enable(struct cec_adapter *adap, bool enable)
 325 {
 326         struct tda9950_priv *priv = adap->priv;
 327
 328         if (!enable) {
 329                 tda9950_release(priv);
 330                 return 0;
 331         } else {
 332                 return tda9950_open(priv);
 333         }
 334 }
 335
 336 static const struct cec_adap_ops tda9950_cec_ops = {
 337         .adap_enable = tda9950_cec_adap_enable,
 338         .adap_log_addr = tda9950_cec_adap_log_addr,
 339         .adap_transmit = tda9950_cec_transmit,
 340 };
 341
 342 /*
 343  * When operating as part of the TDA998x, we need to claim additional
 344  * resources.  These two hooks permit the management of those resources.
 345  */
 346 static void tda9950_devm_glue_exit(void *data)
 347 {
 348         struct tda9950_glue *glue = data;
 349
 350         if (glue && glue->exit)
 351                 glue->exit(glue->data);
 352 }
 353
 354 static int tda9950_devm_glue_init(struct device *dev, struct tda9950_glue *glue)
 355 {
 356         int ret;
 357
 358         if (glue && glue->init) {
 359                 ret = glue->init(glue->data);
 360                 if (ret)
 361                         return ret;
 362         }
 363
 364         ret = devm_add_action(dev, tda9950_devm_glue_exit, glue);
 365         if (ret)
 366                 tda9950_devm_glue_exit(glue);
 367
 368         return ret;
 369 }
 370
 371 static void tda9950_cec_del(void *data)
 372 {
 373         struct tda9950_priv *priv = data;
 374
 375         cec_delete_adapter(priv->adap);
 376 }
 377
 378 static int tda9950_probe(struct i2c_client *client,
 379                          const struct i2c_device_id *id)
 380 {
 381         struct tda9950_glue *glue = client->dev.platform_data;
 382         struct device *dev = &client->dev;
 383         struct tda9950_priv *priv;
 384         unsigned long irqflags;
 385         int ret;
 386         u8 cvr;
 387
 388         /*
 389          * We must have I2C functionality: our multi-byte accesses
 390          * must be performed as a single contiguous transaction.
 391          */
 392         if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 393                 dev_err(&client->dev,
 394                         "adapter does not support I2C functionality\n");
 395                 return -ENXIO;
 396         }
 397
 398         /* We must have an interrupt to be functional. */
 399         if (client->irq <= 0) {
 400                 dev_err(&client->dev, "driver requires an interrupt\n");
 401                 return -ENXIO;
 402         }
 403
 404         priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 405         if (!priv)
 406                 return -ENOMEM;
 407
 408         priv->client = client;
 409         priv->glue = glue;
 410
 411         i2c_set_clientdata(client, priv);
 412
 413         /*
 414          * If we're part of a TDA998x, we want the class devices to be
 415          * associated with the HDMI Tx so we have a tight relationship
 416          * between the HDMI interface and the CEC interface.
 417          */
 418         priv->hdmi = dev;
 419         if (glue && glue->parent)
 420                 priv->hdmi = glue->parent;
 421
 422         priv->adap = cec_allocate_adapter(&tda9950_cec_ops, priv, "tda9950",
 423                                           CEC_CAP_DEFAULTS |
 424                                           CEC_CAP_CONNECTOR_INFO,
 425                                           CEC_MAX_LOG_ADDRS);
 426         if (IS_ERR(priv->adap))
 427                 return PTR_ERR(priv->adap);
 428
 429         ret = devm_add_action(dev, tda9950_cec_del, priv);
 430         if (ret) {
 431                 cec_delete_adapter(priv->adap);
 432                 return ret;
 433         }
 434
 435         ret = tda9950_devm_glue_init(dev, glue);
 436         if (ret)
 437                 return ret;
 438
 439         ret = tda9950_glue_open(priv);
 440         if (ret)
 441                 return ret;
 442
 443         cvr = tda9950_read(client, REG_CVR);
 444
 445         dev_info(&client->dev,
 446                  "TDA9950 CEC interface, hardware version %u.%u\n",
 447                  cvr >> 4, cvr & 15);
 448
 449         tda9950_glue_release(priv);
 450
 451         irqflags = IRQF_TRIGGER_FALLING;
 452         if (glue)
 453                 irqflags = glue->irq_flags;
 454
 455         ret = devm_request_threaded_irq(dev, client->irq, NULL, tda9950_irq,
 456                                         irqflags | IRQF_SHARED | IRQF_ONESHOT,
 457                                         dev_name(&client->dev), priv);
 458         if (ret < 0)
 459                 return ret;
 460
 461         priv->notify = cec_notifier_cec_adap_register(priv->hdmi, NULL,
 462                                                       priv->adap);
 463         if (!priv->notify)
 464                 return -ENOMEM;
 465
 466         ret = cec_register_adapter(priv->adap, priv->hdmi);
 467         if (ret < 0) {
 468                 cec_notifier_cec_adap_unregister(priv->notify, priv->adap);
 469                 return ret;
 470         }
 471
 472         /*
 473          * CEC documentation says we must not call cec_delete_adapter
 474          * after a successful call to cec_register_adapter().
 475          */
 476         devm_remove_action(dev, tda9950_cec_del, priv);
 477
 478         return 0;
 479 }
 480
 481 static int tda9950_remove(struct i2c_client *client)
 482 {
 483         struct tda9950_priv *priv = i2c_get_clientdata(client);
 484
 485         cec_notifier_cec_adap_unregister(priv->notify, priv->adap);
 486         cec_unregister_adapter(priv->adap);
 487
 488         return 0;
 489 }
 490
 491 static struct i2c_device_id tda9950_ids[] = {
 492         { "tda9950", 0 },
 493         { },
 494 };
 495 MODULE_DEVICE_TABLE(i2c, tda9950_ids);
 496
 497 static struct i2c_driver tda9950_driver = {
 498         .probe = tda9950_probe,
 499         .remove = tda9950_remove,
 500         .driver = {
 501                 .name = "tda9950",
 502         },
 503         .id_table = tda9950_ids,
 504 };
 505
 506 module_i2c_driver(tda9950_driver);
 507
 508 MODULE_AUTHOR("Russell King <rmk+kernel@armlinux.org.uk>");
 509 MODULE_DESCRIPTION("TDA9950/TDA998x Consumer Electronics Control Driver");
 510 MODULE_LICENSE("GPL v2");