drivers/input/rmi4/rmi_spi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2011-2016 Synaptics Incorporated
   4  * Copyright (c) 2011 Unixphere
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/rmi.h>
  10 #include <linux/slab.h>
  11 #include <linux/spi/spi.h>
  12 #include <linux/of.h>
  13 #include "rmi_driver.h"
  14
  15 #define RMI_SPI_DEFAULT_XFER_BUF_SIZE   64
  16
  17 #define RMI_PAGE_SELECT_REGISTER        0x00FF
  18 #define RMI_SPI_PAGE(addr)              (((addr) >> 8) & 0x80)
  19 #define RMI_SPI_XFER_SIZE_LIMIT         255
  20
  21 #define BUFFER_SIZE_INCREMENT 32
  22
  23 enum rmi_spi_op {
  24         RMI_SPI_WRITE = 0,
  25         RMI_SPI_READ,
  26         RMI_SPI_V2_READ_UNIFIED,
  27         RMI_SPI_V2_READ_SPLIT,
  28         RMI_SPI_V2_WRITE,
  29 };
  30
  31 struct rmi_spi_cmd {
  32         enum rmi_spi_op op;
  33         u16 addr;
  34 };
  35
  36 struct rmi_spi_xport {
  37         struct rmi_transport_dev xport;
  38         struct spi_device *spi;
  39
  40         struct mutex page_mutex;
  41         int page;
  42
  43         u8 *rx_buf;
  44         u8 *tx_buf;
  45         int xfer_buf_size;
  46
  47         struct spi_transfer *rx_xfers;
  48         struct spi_transfer *tx_xfers;
  49         int rx_xfer_count;
  50         int tx_xfer_count;
  51 };
  52
  53 static int rmi_spi_manage_pools(struct rmi_spi_xport *rmi_spi, int len)
  54 {
  55         struct spi_device *spi = rmi_spi->spi;
  56         int buf_size = rmi_spi->xfer_buf_size
  57                 ? rmi_spi->xfer_buf_size : RMI_SPI_DEFAULT_XFER_BUF_SIZE;
  58         struct spi_transfer *xfer_buf;
  59         void *buf;
  60         void *tmp;
  61
  62         while (buf_size < len)
  63                 buf_size *= 2;
  64
  65         if (buf_size > RMI_SPI_XFER_SIZE_LIMIT)
  66                 buf_size = RMI_SPI_XFER_SIZE_LIMIT;
  67
  68         tmp = rmi_spi->rx_buf;
  69         buf = devm_kcalloc(&spi->dev, buf_size, 2,
  70                                 GFP_KERNEL | GFP_DMA);
  71         if (!buf)
  72                 return -ENOMEM;
  73
  74         rmi_spi->rx_buf = buf;
  75         rmi_spi->tx_buf = &rmi_spi->rx_buf[buf_size];
  76         rmi_spi->xfer_buf_size = buf_size;
  77
  78         if (tmp)
  79                 devm_kfree(&spi->dev, tmp);
  80
  81         if (rmi_spi->xport.pdata.spi_data.read_delay_us)
  82                 rmi_spi->rx_xfer_count = buf_size;
  83         else
  84                 rmi_spi->rx_xfer_count = 1;
  85
  86         if (rmi_spi->xport.pdata.spi_data.write_delay_us)
  87                 rmi_spi->tx_xfer_count = buf_size;
  88         else
  89                 rmi_spi->tx_xfer_count = 1;
  90
  91         /*
  92          * Allocate a pool of spi_transfer buffers for devices which need
  93          * per byte delays.
  94          */
  95         tmp = rmi_spi->rx_xfers;
  96         xfer_buf = devm_kcalloc(&spi->dev,
  97                 rmi_spi->rx_xfer_count + rmi_spi->tx_xfer_count,
  98                 sizeof(struct spi_transfer),
  99                 GFP_KERNEL);
 100         if (!xfer_buf)
 101                 return -ENOMEM;
 102
 103         rmi_spi->rx_xfers = xfer_buf;
 104         rmi_spi->tx_xfers = &xfer_buf[rmi_spi->rx_xfer_count];
 105
 106         if (tmp)
 107                 devm_kfree(&spi->dev, tmp);
 108
 109         return 0;
 110 }
 111
 112 static int rmi_spi_xfer(struct rmi_spi_xport *rmi_spi,
 113                         const struct rmi_spi_cmd *cmd, const u8 *tx_buf,
 114                         int tx_len, u8 *rx_buf, int rx_len)
 115 {
 116         struct spi_device *spi = rmi_spi->spi;
 117         struct rmi_device_platform_data_spi *spi_data =
 118                                         &rmi_spi->xport.pdata.spi_data;
 119         struct spi_message msg;
 120         struct spi_transfer *xfer;
 121         int ret = 0;
 122         int len;
 123         int cmd_len = 0;
 124         int total_tx_len;
 125         int i;
 126         u16 addr = cmd->addr;
 127
 128         spi_message_init(&msg);
 129
 130         switch (cmd->op) {
 131         case RMI_SPI_WRITE:
 132         case RMI_SPI_READ:
 133                 cmd_len += 2;
 134                 break;
 135         case RMI_SPI_V2_READ_UNIFIED:
 136         case RMI_SPI_V2_READ_SPLIT:
 137         case RMI_SPI_V2_WRITE:
 138                 cmd_len += 4;
 139                 break;
 140         }
 141
 142         total_tx_len = cmd_len + tx_len;
 143         len = max(total_tx_len, rx_len);
 144
 145         if (len > RMI_SPI_XFER_SIZE_LIMIT)
 146                 return -EINVAL;
 147
 148         if (rmi_spi->xfer_buf_size < len) {
 149                 ret = rmi_spi_manage_pools(rmi_spi, len);
 150                 if (ret < 0)
 151                         return ret;
 152         }
 153
 154         if (addr == 0)
 155                 /*
 156                  * SPI needs an address. Use 0x7FF if we want to keep
 157                  * reading from the last position of the register pointer.
 158                  */
 159                 addr = 0x7FF;
 160
 161         switch (cmd->op) {
 162         case RMI_SPI_WRITE:
 163                 rmi_spi->tx_buf[0] = (addr >> 8);
 164                 rmi_spi->tx_buf[1] = addr & 0xFF;
 165                 break;
 166         case RMI_SPI_READ:
 167                 rmi_spi->tx_buf[0] = (addr >> 8) | 0x80;
 168                 rmi_spi->tx_buf[1] = addr & 0xFF;
 169                 break;
 170         case RMI_SPI_V2_READ_UNIFIED:
 171                 break;
 172         case RMI_SPI_V2_READ_SPLIT:
 173                 break;
 174         case RMI_SPI_V2_WRITE:
 175                 rmi_spi->tx_buf[0] = 0x40;
 176                 rmi_spi->tx_buf[1] = (addr >> 8) & 0xFF;
 177                 rmi_spi->tx_buf[2] = addr & 0xFF;
 178                 rmi_spi->tx_buf[3] = tx_len;
 179                 break;
 180         }
 181
 182         if (tx_buf)
 183                 memcpy(&rmi_spi->tx_buf[cmd_len], tx_buf, tx_len);
 184
 185         if (rmi_spi->tx_xfer_count > 1) {
 186                 for (i = 0; i < total_tx_len; i++) {
 187                         xfer = &rmi_spi->tx_xfers[i];
 188                         memset(xfer, 0, sizeof(struct spi_transfer));
 189                         xfer->tx_buf = &rmi_spi->tx_buf[i];
 190                         xfer->len = 1;
 191                         xfer->delay.value = spi_data->write_delay_us;
 192                         xfer->delay.unit = SPI_DELAY_UNIT_USECS;
 193                         spi_message_add_tail(xfer, &msg);
 194                 }
 195         } else {
 196                 xfer = rmi_spi->tx_xfers;
 197                 memset(xfer, 0, sizeof(struct spi_transfer));
 198                 xfer->tx_buf = rmi_spi->tx_buf;
 199                 xfer->len = total_tx_len;
 200                 spi_message_add_tail(xfer, &msg);
 201         }
 202
 203         rmi_dbg(RMI_DEBUG_XPORT, &spi->dev, "%s: cmd: %s tx_buf len: %d tx_buf: %*ph\n",
 204                 __func__, cmd->op == RMI_SPI_WRITE ? "WRITE" : "READ",
 205                 total_tx_len, total_tx_len, rmi_spi->tx_buf);
 206
 207         if (rx_buf) {
 208                 if (rmi_spi->rx_xfer_count > 1) {
 209                         for (i = 0; i < rx_len; i++) {
 210                                 xfer = &rmi_spi->rx_xfers[i];
 211                                 memset(xfer, 0, sizeof(struct spi_transfer));
 212                                 xfer->rx_buf = &rmi_spi->rx_buf[i];
 213                                 xfer->len = 1;
 214                                 xfer->delay.value = spi_data->read_delay_us;
 215                                 xfer->delay.unit = SPI_DELAY_UNIT_USECS;
 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 #ifdef CONFIG_OF
 330 static int rmi_spi_of_probe(struct spi_device *spi,
 331                         struct rmi_device_platform_data *pdata)
 332 {
 333         struct device *dev = &spi->dev;
 334         int retval;
 335
 336         retval = rmi_of_property_read_u32(dev,
 337                         &pdata->spi_data.read_delay_us,
 338                         "spi-rx-delay-us", 1);
 339         if (retval)
 340                 return retval;
 341
 342         retval = rmi_of_property_read_u32(dev,
 343                         &pdata->spi_data.write_delay_us,
 344                         "spi-tx-delay-us", 1);
 345         if (retval)
 346                 return retval;
 347
 348         return 0;
 349 }
 350
 351 static const struct of_device_id rmi_spi_of_match[] = {
 352         { .compatible = "syna,rmi4-spi" },
 353         {},
 354 };
 355 MODULE_DEVICE_TABLE(of, rmi_spi_of_match);
 356 #else
 357 static inline int rmi_spi_of_probe(struct spi_device *spi,
 358                                 struct rmi_device_platform_data *pdata)
 359 {
 360         return -ENODEV;
 361 }
 362 #endif
 363
 364 static void rmi_spi_unregister_transport(void *data)
 365 {
 366         struct rmi_spi_xport *rmi_spi = data;
 367
 368         rmi_unregister_transport_device(&rmi_spi->xport);
 369 }
 370
 371 static int rmi_spi_probe(struct spi_device *spi)
 372 {
 373         struct rmi_spi_xport *rmi_spi;
 374         struct rmi_device_platform_data *pdata;
 375         struct rmi_device_platform_data *spi_pdata = spi->dev.platform_data;
 376         int error;
 377
 378         if (spi->master->flags & SPI_MASTER_HALF_DUPLEX)
 379                 return -EINVAL;
 380
 381         rmi_spi = devm_kzalloc(&spi->dev, sizeof(struct rmi_spi_xport),
 382                         GFP_KERNEL);
 383         if (!rmi_spi)
 384                 return -ENOMEM;
 385
 386         pdata = &rmi_spi->xport.pdata;
 387
 388         if (spi->dev.of_node) {
 389                 error = rmi_spi_of_probe(spi, pdata);
 390                 if (error)
 391                         return error;
 392         } else if (spi_pdata) {
 393                 *pdata = *spi_pdata;
 394         }
 395
 396         if (pdata->spi_data.bits_per_word)
 397                 spi->bits_per_word = pdata->spi_data.bits_per_word;
 398
 399         if (pdata->spi_data.mode)
 400                 spi->mode = pdata->spi_data.mode;
 401
 402         error = spi_setup(spi);
 403         if (error < 0) {
 404                 dev_err(&spi->dev, "spi_setup failed!\n");
 405                 return error;
 406         }
 407
 408         pdata->irq = spi->irq;
 409
 410         rmi_spi->spi = spi;
 411         mutex_init(&rmi_spi->page_mutex);
 412
 413         rmi_spi->xport.dev = &spi->dev;
 414         rmi_spi->xport.proto_name = "spi";
 415         rmi_spi->xport.ops = &rmi_spi_ops;
 416
 417         spi_set_drvdata(spi, rmi_spi);
 418
 419         error = rmi_spi_manage_pools(rmi_spi, RMI_SPI_DEFAULT_XFER_BUF_SIZE);
 420         if (error)
 421                 return error;
 422
 423         /*
 424          * Setting the page to zero will (a) make sure the PSR is in a
 425          * known state, and (b) make sure we can talk to the device.
 426          */
 427         error = rmi_set_page(rmi_spi, 0);
 428         if (error) {
 429                 dev_err(&spi->dev, "Failed to set page select to 0.\n");
 430                 return error;
 431         }
 432
 433         dev_info(&spi->dev, "registering SPI-connected sensor\n");
 434
 435         error = rmi_register_transport_device(&rmi_spi->xport);
 436         if (error) {
 437                 dev_err(&spi->dev, "failed to register sensor: %d\n", error);
 438                 return error;
 439         }
 440
 441         error = devm_add_action_or_reset(&spi->dev,
 442                                           rmi_spi_unregister_transport,
 443                                           rmi_spi);
 444         if (error)
 445                 return error;
 446
 447         return 0;
 448 }
 449
 450 #ifdef CONFIG_PM_SLEEP
 451 static int rmi_spi_suspend(struct device *dev)
 452 {
 453         struct spi_device *spi = to_spi_device(dev);
 454         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 455         int ret;
 456
 457         ret = rmi_driver_suspend(rmi_spi->xport.rmi_dev, true);
 458         if (ret)
 459                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 460
 461         return ret;
 462 }
 463
 464 static int rmi_spi_resume(struct device *dev)
 465 {
 466         struct spi_device *spi = to_spi_device(dev);
 467         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 468         int ret;
 469
 470         ret = rmi_driver_resume(rmi_spi->xport.rmi_dev, true);
 471         if (ret)
 472                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 473
 474         return ret;
 475 }
 476 #endif
 477
 478 #ifdef CONFIG_PM
 479 static int rmi_spi_runtime_suspend(struct device *dev)
 480 {
 481         struct spi_device *spi = to_spi_device(dev);
 482         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 483         int ret;
 484
 485         ret = rmi_driver_suspend(rmi_spi->xport.rmi_dev, false);
 486         if (ret)
 487                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 488
 489         return 0;
 490 }
 491
 492 static int rmi_spi_runtime_resume(struct device *dev)
 493 {
 494         struct spi_device *spi = to_spi_device(dev);
 495         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 496         int ret;
 497
 498         ret = rmi_driver_resume(rmi_spi->xport.rmi_dev, false);
 499         if (ret)
 500                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 501
 502         return 0;
 503 }
 504 #endif
 505
 506 static const struct dev_pm_ops rmi_spi_pm = {
 507         SET_SYSTEM_SLEEP_PM_OPS(rmi_spi_suspend, rmi_spi_resume)
 508         SET_RUNTIME_PM_OPS(rmi_spi_runtime_suspend, rmi_spi_runtime_resume,
 509                            NULL)
 510 };
 511
 512 static const struct spi_device_id rmi_id[] = {
 513         { "rmi4_spi", 0 },
 514         { }
 515 };
 516 MODULE_DEVICE_TABLE(spi, rmi_id);
 517
 518 static struct spi_driver rmi_spi_driver = {
 519         .driver = {
 520                 .name   = "rmi4_spi",
 521                 .pm     = &rmi_spi_pm,
 522                 .of_match_table = of_match_ptr(rmi_spi_of_match),
 523         },
 524         .id_table       = rmi_id,
 525         .probe          = rmi_spi_probe,
 526 };
 527
 528 module_spi_driver(rmi_spi_driver);
 529
 530 MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>");
 531 MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
 532 MODULE_DESCRIPTION("RMI SPI driver");
 533 MODULE_LICENSE("GPL");