drivers/input/rmi4/rmi_spi.c

   1 /*
   2  * Copyright (c) 2011-2016 Synaptics Incorporated
   3  * Copyright (c) 2011 Unixphere
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 as published by
   7  * the Free Software Foundation.
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/rmi.h>
  13 #include <linux/slab.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/irq.h>
  16 #include <linux/of.h>
  17 #include "rmi_driver.h"
  18
  19 #define RMI_SPI_DEFAULT_XFER_BUF_SIZE   64
  20
  21 #define RMI_PAGE_SELECT_REGISTER        0x00FF
  22 #define RMI_SPI_PAGE(addr)              (((addr) >> 8) & 0x80)
  23 #define RMI_SPI_XFER_SIZE_LIMIT         255
  24
  25 #define BUFFER_SIZE_INCREMENT 32
  26
  27 enum rmi_spi_op {
  28         RMI_SPI_WRITE = 0,
  29         RMI_SPI_READ,
  30         RMI_SPI_V2_READ_UNIFIED,
  31         RMI_SPI_V2_READ_SPLIT,
  32         RMI_SPI_V2_WRITE,
  33 };
  34
  35 struct rmi_spi_cmd {
  36         enum rmi_spi_op op;
  37         u16 addr;
  38 };
  39
  40 struct rmi_spi_xport {
  41         struct rmi_transport_dev xport;
  42         struct spi_device *spi;
  43
  44         struct mutex page_mutex;
  45         int page;
  46
  47         int irq;
  48
  49         u8 *rx_buf;
  50         u8 *tx_buf;
  51         int xfer_buf_size;
  52
  53         struct spi_transfer *rx_xfers;
  54         struct spi_transfer *tx_xfers;
  55         int rx_xfer_count;
  56         int tx_xfer_count;
  57 };
  58
  59 static int rmi_spi_manage_pools(struct rmi_spi_xport *rmi_spi, int len)
  60 {
  61         struct spi_device *spi = rmi_spi->spi;
  62         int buf_size = rmi_spi->xfer_buf_size
  63                 ? rmi_spi->xfer_buf_size : RMI_SPI_DEFAULT_XFER_BUF_SIZE;
  64         struct spi_transfer *xfer_buf;
  65         void *buf;
  66         void *tmp;
  67
  68         while (buf_size < len)
  69                 buf_size *= 2;
  70
  71         if (buf_size > RMI_SPI_XFER_SIZE_LIMIT)
  72                 buf_size = RMI_SPI_XFER_SIZE_LIMIT;
  73
  74         tmp = rmi_spi->rx_buf;
  75         buf = devm_kzalloc(&spi->dev, buf_size * 2,
  76                                 GFP_KERNEL | GFP_DMA);
  77         if (!buf)
  78                 return -ENOMEM;
  79
  80         rmi_spi->rx_buf = buf;
  81         rmi_spi->tx_buf = &rmi_spi->rx_buf[buf_size];
  82         rmi_spi->xfer_buf_size = buf_size;
  83
  84         if (tmp)
  85                 devm_kfree(&spi->dev, tmp);
  86
  87         if (rmi_spi->xport.pdata.spi_data.read_delay_us)
  88                 rmi_spi->rx_xfer_count = buf_size;
  89         else
  90                 rmi_spi->rx_xfer_count = 1;
  91
  92         if (rmi_spi->xport.pdata.spi_data.write_delay_us)
  93                 rmi_spi->tx_xfer_count = buf_size;
  94         else
  95                 rmi_spi->tx_xfer_count = 1;
  96
  97         /*
  98          * Allocate a pool of spi_transfer buffers for devices which need
  99          * per byte delays.
 100          */
 101         tmp = rmi_spi->rx_xfers;
 102         xfer_buf = devm_kzalloc(&spi->dev,
 103                 (rmi_spi->rx_xfer_count + rmi_spi->tx_xfer_count)
 104                 * sizeof(struct spi_transfer), GFP_KERNEL);
 105         if (!xfer_buf)
 106                 return -ENOMEM;
 107
 108         rmi_spi->rx_xfers = xfer_buf;
 109         rmi_spi->tx_xfers = &xfer_buf[rmi_spi->rx_xfer_count];
 110
 111         if (tmp)
 112                 devm_kfree(&spi->dev, tmp);
 113
 114         return 0;
 115 }
 116
 117 static int rmi_spi_xfer(struct rmi_spi_xport *rmi_spi,
 118                         const struct rmi_spi_cmd *cmd, const u8 *tx_buf,
 119                         int tx_len, u8 *rx_buf, int rx_len)
 120 {
 121         struct spi_device *spi = rmi_spi->spi;
 122         struct rmi_device_platform_data_spi *spi_data =
 123                                         &rmi_spi->xport.pdata.spi_data;
 124         struct spi_message msg;
 125         struct spi_transfer *xfer;
 126         int ret = 0;
 127         int len;
 128         int cmd_len = 0;
 129         int total_tx_len;
 130         int i;
 131         u16 addr = cmd->addr;
 132
 133         spi_message_init(&msg);
 134
 135         switch (cmd->op) {
 136         case RMI_SPI_WRITE:
 137         case RMI_SPI_READ:
 138                 cmd_len += 2;
 139                 break;
 140         case RMI_SPI_V2_READ_UNIFIED:
 141         case RMI_SPI_V2_READ_SPLIT:
 142         case RMI_SPI_V2_WRITE:
 143                 cmd_len += 4;
 144                 break;
 145         }
 146
 147         total_tx_len = cmd_len + tx_len;
 148         len = max(total_tx_len, rx_len);
 149
 150         if (len > RMI_SPI_XFER_SIZE_LIMIT)
 151                 return -EINVAL;
 152
 153         if (rmi_spi->xfer_buf_size < len)
 154                 rmi_spi_manage_pools(rmi_spi, len);
 155
 156         if (addr == 0)
 157                 /*
 158                  * SPI needs an address. Use 0x7FF if we want to keep
 159                  * reading from the last position of the register pointer.
 160                  */
 161                 addr = 0x7FF;
 162
 163         switch (cmd->op) {
 164         case RMI_SPI_WRITE:
 165                 rmi_spi->tx_buf[0] = (addr >> 8);
 166                 rmi_spi->tx_buf[1] = addr & 0xFF;
 167                 break;
 168         case RMI_SPI_READ:
 169                 rmi_spi->tx_buf[0] = (addr >> 8) | 0x80;
 170                 rmi_spi->tx_buf[1] = addr & 0xFF;
 171                 break;
 172         case RMI_SPI_V2_READ_UNIFIED:
 173                 break;
 174         case RMI_SPI_V2_READ_SPLIT:
 175                 break;
 176         case RMI_SPI_V2_WRITE:
 177                 rmi_spi->tx_buf[0] = 0x40;
 178                 rmi_spi->tx_buf[1] = (addr >> 8) & 0xFF;
 179                 rmi_spi->tx_buf[2] = addr & 0xFF;
 180                 rmi_spi->tx_buf[3] = tx_len;
 181                 break;
 182         }
 183
 184         if (tx_buf)
 185                 memcpy(&rmi_spi->tx_buf[cmd_len], tx_buf, tx_len);
 186
 187         if (rmi_spi->tx_xfer_count > 1) {
 188                 for (i = 0; i < total_tx_len; i++) {
 189                         xfer = &rmi_spi->tx_xfers[i];
 190                         memset(xfer, 0, sizeof(struct spi_transfer));
 191                         xfer->tx_buf = &rmi_spi->tx_buf[i];
 192                         xfer->len = 1;
 193                         xfer->delay_usecs = spi_data->write_delay_us;
 194                         spi_message_add_tail(xfer, &msg);
 195                 }
 196         } else {
 197                 xfer = rmi_spi->tx_xfers;
 198                 memset(xfer, 0, sizeof(struct spi_transfer));
 199                 xfer->tx_buf = rmi_spi->tx_buf;
 200                 xfer->len = total_tx_len;
 201                 spi_message_add_tail(xfer, &msg);
 202         }
 203
 204         rmi_dbg(RMI_DEBUG_XPORT, &spi->dev, "%s: cmd: %s tx_buf len: %d tx_buf: %*ph\n",
 205                 __func__, cmd->op == RMI_SPI_WRITE ? "WRITE" : "READ",
 206                 total_tx_len, total_tx_len, rmi_spi->tx_buf);
 207
 208         if (rx_buf) {
 209                 if (rmi_spi->rx_xfer_count > 1) {
 210                         for (i = 0; i < rx_len; i++) {
 211                                 xfer = &rmi_spi->rx_xfers[i];
 212                                 memset(xfer, 0, sizeof(struct spi_transfer));
 213                                 xfer->rx_buf = &rmi_spi->rx_buf[i];
 214                                 xfer->len = 1;
 215                                 xfer->delay_usecs = spi_data->read_delay_us;
 216                                 spi_message_add_tail(xfer, &msg);
 217                         }
 218                 } else {
 219                         xfer = rmi_spi->rx_xfers;
 220                         memset(xfer, 0, sizeof(struct spi_transfer));
 221                         xfer->rx_buf = rmi_spi->rx_buf;
 222                         xfer->len = rx_len;
 223                         spi_message_add_tail(xfer, &msg);
 224                 }
 225         }
 226
 227         ret = spi_sync(spi, &msg);
 228         if (ret < 0) {
 229                 dev_err(&spi->dev, "spi xfer failed: %d\n", ret);
 230                 return ret;
 231         }
 232
 233         if (rx_buf) {
 234                 memcpy(rx_buf, rmi_spi->rx_buf, rx_len);
 235                 rmi_dbg(RMI_DEBUG_XPORT, &spi->dev, "%s: (%d) %*ph\n",
 236                         __func__, rx_len, rx_len, rx_buf);
 237         }
 238
 239         return 0;
 240 }
 241
 242 /*
 243  * rmi_set_page - Set RMI page
 244  * @xport: The pointer to the rmi_transport_dev struct
 245  * @page: The new page address.
 246  *
 247  * RMI devices have 16-bit addressing, but some of the transport
 248  * implementations (like SMBus) only have 8-bit addressing. So RMI implements
 249  * a page address at 0xff of every page so we can reliable page addresses
 250  * every 256 registers.
 251  *
 252  * The page_mutex lock must be held when this function is entered.
 253  *
 254  * Returns zero on success, non-zero on failure.
 255  */
 256 static int rmi_set_page(struct rmi_spi_xport *rmi_spi, u8 page)
 257 {
 258         struct rmi_spi_cmd cmd;
 259         int ret;
 260
 261         cmd.op = RMI_SPI_WRITE;
 262         cmd.addr = RMI_PAGE_SELECT_REGISTER;
 263
 264         ret = rmi_spi_xfer(rmi_spi, &cmd, &page, 1, NULL, 0);
 265
 266         if (ret)
 267                 rmi_spi->page = page;
 268
 269         return ret;
 270 }
 271
 272 static int rmi_spi_write_block(struct rmi_transport_dev *xport, u16 addr,
 273                                const void *buf, size_t len)
 274 {
 275         struct rmi_spi_xport *rmi_spi =
 276                 container_of(xport, struct rmi_spi_xport, xport);
 277         struct rmi_spi_cmd cmd;
 278         int ret;
 279
 280         mutex_lock(&rmi_spi->page_mutex);
 281
 282         if (RMI_SPI_PAGE(addr) != rmi_spi->page) {
 283                 ret = rmi_set_page(rmi_spi, RMI_SPI_PAGE(addr));
 284                 if (ret)
 285                         goto exit;
 286         }
 287
 288         cmd.op = RMI_SPI_WRITE;
 289         cmd.addr = addr;
 290
 291         ret = rmi_spi_xfer(rmi_spi, &cmd, buf, len, NULL, 0);
 292
 293 exit:
 294         mutex_unlock(&rmi_spi->page_mutex);
 295         return ret;
 296 }
 297
 298 static int rmi_spi_read_block(struct rmi_transport_dev *xport, u16 addr,
 299                               void *buf, size_t len)
 300 {
 301         struct rmi_spi_xport *rmi_spi =
 302                 container_of(xport, struct rmi_spi_xport, xport);
 303         struct rmi_spi_cmd cmd;
 304         int ret;
 305
 306         mutex_lock(&rmi_spi->page_mutex);
 307
 308         if (RMI_SPI_PAGE(addr) != rmi_spi->page) {
 309                 ret = rmi_set_page(rmi_spi, RMI_SPI_PAGE(addr));
 310                 if (ret)
 311                         goto exit;
 312         }
 313
 314         cmd.op = RMI_SPI_READ;
 315         cmd.addr = addr;
 316
 317         ret = rmi_spi_xfer(rmi_spi, &cmd, NULL, 0, buf, len);
 318
 319 exit:
 320         mutex_unlock(&rmi_spi->page_mutex);
 321         return ret;
 322 }
 323
 324 static const struct rmi_transport_ops rmi_spi_ops = {
 325         .write_block    = rmi_spi_write_block,
 326         .read_block     = rmi_spi_read_block,
 327 };
 328
 329 static irqreturn_t rmi_spi_irq(int irq, void *dev_id)
 330 {
 331         struct rmi_spi_xport *rmi_spi = dev_id;
 332         struct rmi_device *rmi_dev = rmi_spi->xport.rmi_dev;
 333         int ret;
 334
 335         ret = rmi_process_interrupt_requests(rmi_dev);
 336         if (ret)
 337                 rmi_dbg(RMI_DEBUG_XPORT, &rmi_dev->dev,
 338                         "Failed to process interrupt request: %d\n", ret);
 339
 340         return IRQ_HANDLED;
 341 }
 342
 343 static int rmi_spi_init_irq(struct spi_device *spi)
 344 {
 345         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 346         int irq_flags = irqd_get_trigger_type(irq_get_irq_data(rmi_spi->irq));
 347         int ret;
 348
 349         if (!irq_flags)
 350                 irq_flags = IRQF_TRIGGER_LOW;
 351
 352         ret = devm_request_threaded_irq(&spi->dev, rmi_spi->irq, NULL,
 353                         rmi_spi_irq, irq_flags | IRQF_ONESHOT,
 354                         dev_name(&spi->dev), rmi_spi);
 355         if (ret < 0) {
 356                 dev_warn(&spi->dev, "Failed to register interrupt %d\n",
 357                         rmi_spi->irq);
 358                 return ret;
 359         }
 360
 361         return 0;
 362 }
 363
 364 #ifdef CONFIG_OF
 365 static int rmi_spi_of_probe(struct spi_device *spi,
 366                         struct rmi_device_platform_data *pdata)
 367 {
 368         struct device *dev = &spi->dev;
 369         int retval;
 370
 371         retval = rmi_of_property_read_u32(dev,
 372                         &pdata->spi_data.read_delay_us,
 373                         "spi-rx-delay-us", 1);
 374         if (retval)
 375                 return retval;
 376
 377         retval = rmi_of_property_read_u32(dev,
 378                         &pdata->spi_data.write_delay_us,
 379                         "spi-tx-delay-us", 1);
 380         if (retval)
 381                 return retval;
 382
 383         return 0;
 384 }
 385
 386 static const struct of_device_id rmi_spi_of_match[] = {
 387         { .compatible = "syna,rmi4-spi" },
 388         {},
 389 };
 390 MODULE_DEVICE_TABLE(of, rmi_spi_of_match);
 391 #else
 392 static inline int rmi_spi_of_probe(struct spi_device *spi,
 393                                 struct rmi_device_platform_data *pdata)
 394 {
 395         return -ENODEV;
 396 }
 397 #endif
 398
 399 static void rmi_spi_unregister_transport(void *data)
 400 {
 401         struct rmi_spi_xport *rmi_spi = data;
 402
 403         rmi_unregister_transport_device(&rmi_spi->xport);
 404 }
 405
 406 static int rmi_spi_probe(struct spi_device *spi)
 407 {
 408         struct rmi_spi_xport *rmi_spi;
 409         struct rmi_device_platform_data *pdata;
 410         struct rmi_device_platform_data *spi_pdata = spi->dev.platform_data;
 411         int retval;
 412
 413         if (spi->master->flags & SPI_MASTER_HALF_DUPLEX)
 414                 return -EINVAL;
 415
 416         rmi_spi = devm_kzalloc(&spi->dev, sizeof(struct rmi_spi_xport),
 417                         GFP_KERNEL);
 418         if (!rmi_spi)
 419                 return -ENOMEM;
 420
 421         pdata = &rmi_spi->xport.pdata;
 422
 423         if (spi->dev.of_node) {
 424                 retval = rmi_spi_of_probe(spi, pdata);
 425                 if (retval)
 426                         return retval;
 427         } else if (spi_pdata) {
 428                 *pdata = *spi_pdata;
 429         }
 430
 431         if (pdata->spi_data.bits_per_word)
 432                 spi->bits_per_word = pdata->spi_data.bits_per_word;
 433
 434         if (pdata->spi_data.mode)
 435                 spi->mode = pdata->spi_data.mode;
 436
 437         retval = spi_setup(spi);
 438         if (retval < 0) {
 439                 dev_err(&spi->dev, "spi_setup failed!\n");
 440                 return retval;
 441         }
 442
 443         if (spi->irq > 0)
 444                 rmi_spi->irq = spi->irq;
 445
 446         rmi_spi->spi = spi;
 447         mutex_init(&rmi_spi->page_mutex);
 448
 449         rmi_spi->xport.dev = &spi->dev;
 450         rmi_spi->xport.proto_name = "spi";
 451         rmi_spi->xport.ops = &rmi_spi_ops;
 452
 453         spi_set_drvdata(spi, rmi_spi);
 454
 455         retval = rmi_spi_manage_pools(rmi_spi, RMI_SPI_DEFAULT_XFER_BUF_SIZE);
 456         if (retval)
 457                 return retval;
 458
 459         /*
 460          * Setting the page to zero will (a) make sure the PSR is in a
 461          * known state, and (b) make sure we can talk to the device.
 462          */
 463         retval = rmi_set_page(rmi_spi, 0);
 464         if (retval) {
 465                 dev_err(&spi->dev, "Failed to set page select to 0.\n");
 466                 return retval;
 467         }
 468
 469         retval = rmi_register_transport_device(&rmi_spi->xport);
 470         if (retval) {
 471                 dev_err(&spi->dev, "failed to register transport.\n");
 472                 return retval;
 473         }
 474         retval = devm_add_action_or_reset(&spi->dev,
 475                                           rmi_spi_unregister_transport,
 476                                           rmi_spi);
 477         if (retval)
 478                 return retval;
 479
 480         retval = rmi_spi_init_irq(spi);
 481         if (retval < 0)
 482                 return retval;
 483
 484         dev_info(&spi->dev, "registered RMI SPI driver\n");
 485         return 0;
 486 }
 487
 488 #ifdef CONFIG_PM_SLEEP
 489 static int rmi_spi_suspend(struct device *dev)
 490 {
 491         struct spi_device *spi = to_spi_device(dev);
 492         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 493         int ret;
 494
 495         ret = rmi_driver_suspend(rmi_spi->xport.rmi_dev);
 496         if (ret)
 497                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 498
 499         disable_irq(rmi_spi->irq);
 500         if (device_may_wakeup(&spi->dev)) {
 501                 ret = enable_irq_wake(rmi_spi->irq);
 502                 if (!ret)
 503                         dev_warn(dev, "Failed to enable irq for wake: %d\n",
 504                                 ret);
 505         }
 506         return ret;
 507 }
 508
 509 static int rmi_spi_resume(struct device *dev)
 510 {
 511         struct spi_device *spi = to_spi_device(dev);
 512         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 513         int ret;
 514
 515         enable_irq(rmi_spi->irq);
 516         if (device_may_wakeup(&spi->dev)) {
 517                 ret = disable_irq_wake(rmi_spi->irq);
 518                 if (!ret)
 519                         dev_warn(dev, "Failed to disable irq for wake: %d\n",
 520                                 ret);
 521         }
 522
 523         ret = rmi_driver_resume(rmi_spi->xport.rmi_dev);
 524         if (ret)
 525                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 526
 527         return ret;
 528 }
 529 #endif
 530
 531 #ifdef CONFIG_PM
 532 static int rmi_spi_runtime_suspend(struct device *dev)
 533 {
 534         struct spi_device *spi = to_spi_device(dev);
 535         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 536         int ret;
 537
 538         ret = rmi_driver_suspend(rmi_spi->xport.rmi_dev);
 539         if (ret)
 540                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 541
 542         disable_irq(rmi_spi->irq);
 543
 544         return 0;
 545 }
 546
 547 static int rmi_spi_runtime_resume(struct device *dev)
 548 {
 549         struct spi_device *spi = to_spi_device(dev);
 550         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 551         int ret;
 552
 553         enable_irq(rmi_spi->irq);
 554
 555         ret = rmi_driver_resume(rmi_spi->xport.rmi_dev);
 556         if (ret)
 557                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 558
 559         return 0;
 560 }
 561 #endif
 562
 563 static const struct dev_pm_ops rmi_spi_pm = {
 564         SET_SYSTEM_SLEEP_PM_OPS(rmi_spi_suspend, rmi_spi_resume)
 565         SET_RUNTIME_PM_OPS(rmi_spi_runtime_suspend, rmi_spi_runtime_resume,
 566                            NULL)
 567 };
 568
 569 static const struct spi_device_id rmi_id[] = {
 570         { "rmi4_spi", 0 },
 571         { }
 572 };
 573 MODULE_DEVICE_TABLE(spi, rmi_id);
 574
 575 static struct spi_driver rmi_spi_driver = {
 576         .driver = {
 577                 .name   = "rmi4_spi",
 578                 .pm     = &rmi_spi_pm,
 579                 .of_match_table = of_match_ptr(rmi_spi_of_match),
 580         },
 581         .id_table       = rmi_id,
 582         .probe          = rmi_spi_probe,
 583 };
 584
 585 module_spi_driver(rmi_spi_driver);
 586
 587 MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>");
 588 MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
 589 MODULE_DESCRIPTION("RMI SPI driver");
 590 MODULE_LICENSE("GPL");
 591 MODULE_VERSION(RMI_DRIVER_VERSION);