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