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_usecs = spi_data->write_delay_us;
 192                         spi_message_add_tail(xfer, &msg);
 193                 }
 194         } else {
 195                 xfer = rmi_spi->tx_xfers;
 196                 memset(xfer, 0, sizeof(struct spi_transfer));
 197                 xfer->tx_buf = rmi_spi->tx_buf;
 198                 xfer->len = total_tx_len;
 199                 spi_message_add_tail(xfer, &msg);
 200         }
 201
 202         rmi_dbg(RMI_DEBUG_XPORT, &spi->dev, "%s: cmd: %s tx_buf len: %d tx_buf: %*ph\n",
 203                 __func__, cmd->op == RMI_SPI_WRITE ? "WRITE" : "READ",
 204                 total_tx_len, total_tx_len, rmi_spi->tx_buf);
 205
 206         if (rx_buf) {
 207                 if (rmi_spi->rx_xfer_count > 1) {
 208                         for (i = 0; i < rx_len; i++) {
 209                                 xfer = &rmi_spi->rx_xfers[i];
 210                                 memset(xfer, 0, sizeof(struct spi_transfer));
 211                                 xfer->rx_buf = &rmi_spi->rx_buf[i];
 212                                 xfer->len = 1;
 213                                 xfer->delay_usecs = spi_data->read_delay_us;
 214                                 spi_message_add_tail(xfer, &msg);
 215                         }
 216                 } else {
 217                         xfer = rmi_spi->rx_xfers;
 218                         memset(xfer, 0, sizeof(struct spi_transfer));
 219                         xfer->rx_buf = rmi_spi->rx_buf;
 220                         xfer->len = rx_len;
 221                         spi_message_add_tail(xfer, &msg);
 222                 }
 223         }
 224
 225         ret = spi_sync(spi, &msg);
 226         if (ret < 0) {
 227                 dev_err(&spi->dev, "spi xfer failed: %d\n", ret);
 228                 return ret;
 229         }
 230
 231         if (rx_buf) {
 232                 memcpy(rx_buf, rmi_spi->rx_buf, rx_len);
 233                 rmi_dbg(RMI_DEBUG_XPORT, &spi->dev, "%s: (%d) %*ph\n",
 234                         __func__, rx_len, rx_len, rx_buf);
 235         }
 236
 237         return 0;
 238 }
 239
 240 /*
 241  * rmi_set_page - Set RMI page
 242  * @xport: The pointer to the rmi_transport_dev struct
 243  * @page: The new page address.
 244  *
 245  * RMI devices have 16-bit addressing, but some of the transport
 246  * implementations (like SMBus) only have 8-bit addressing. So RMI implements
 247  * a page address at 0xff of every page so we can reliable page addresses
 248  * every 256 registers.
 249  *
 250  * The page_mutex lock must be held when this function is entered.
 251  *
 252  * Returns zero on success, non-zero on failure.
 253  */
 254 static int rmi_set_page(struct rmi_spi_xport *rmi_spi, u8 page)
 255 {
 256         struct rmi_spi_cmd cmd;
 257         int ret;
 258
 259         cmd.op = RMI_SPI_WRITE;
 260         cmd.addr = RMI_PAGE_SELECT_REGISTER;
 261
 262         ret = rmi_spi_xfer(rmi_spi, &cmd, &page, 1, NULL, 0);
 263
 264         if (ret)
 265                 rmi_spi->page = page;
 266
 267         return ret;
 268 }
 269
 270 static int rmi_spi_write_block(struct rmi_transport_dev *xport, u16 addr,
 271                                const void *buf, size_t len)
 272 {
 273         struct rmi_spi_xport *rmi_spi =
 274                 container_of(xport, struct rmi_spi_xport, xport);
 275         struct rmi_spi_cmd cmd;
 276         int ret;
 277
 278         mutex_lock(&rmi_spi->page_mutex);
 279
 280         if (RMI_SPI_PAGE(addr) != rmi_spi->page) {
 281                 ret = rmi_set_page(rmi_spi, RMI_SPI_PAGE(addr));
 282                 if (ret)
 283                         goto exit;
 284         }
 285
 286         cmd.op = RMI_SPI_WRITE;
 287         cmd.addr = addr;
 288
 289         ret = rmi_spi_xfer(rmi_spi, &cmd, buf, len, NULL, 0);
 290
 291 exit:
 292         mutex_unlock(&rmi_spi->page_mutex);
 293         return ret;
 294 }
 295
 296 static int rmi_spi_read_block(struct rmi_transport_dev *xport, u16 addr,
 297                               void *buf, size_t len)
 298 {
 299         struct rmi_spi_xport *rmi_spi =
 300                 container_of(xport, struct rmi_spi_xport, xport);
 301         struct rmi_spi_cmd cmd;
 302         int ret;
 303
 304         mutex_lock(&rmi_spi->page_mutex);
 305
 306         if (RMI_SPI_PAGE(addr) != rmi_spi->page) {
 307                 ret = rmi_set_page(rmi_spi, RMI_SPI_PAGE(addr));
 308                 if (ret)
 309                         goto exit;
 310         }
 311
 312         cmd.op = RMI_SPI_READ;
 313         cmd.addr = addr;
 314
 315         ret = rmi_spi_xfer(rmi_spi, &cmd, NULL, 0, buf, len);
 316
 317 exit:
 318         mutex_unlock(&rmi_spi->page_mutex);
 319         return ret;
 320 }
 321
 322 static const struct rmi_transport_ops rmi_spi_ops = {
 323         .write_block    = rmi_spi_write_block,
 324         .read_block     = rmi_spi_read_block,
 325 };
 326
 327 #ifdef CONFIG_OF
 328 static int rmi_spi_of_probe(struct spi_device *spi,
 329                         struct rmi_device_platform_data *pdata)
 330 {
 331         struct device *dev = &spi->dev;
 332         int retval;
 333
 334         retval = rmi_of_property_read_u32(dev,
 335                         &pdata->spi_data.read_delay_us,
 336                         "spi-rx-delay-us", 1);
 337         if (retval)
 338                 return retval;
 339
 340         retval = rmi_of_property_read_u32(dev,
 341                         &pdata->spi_data.write_delay_us,
 342                         "spi-tx-delay-us", 1);
 343         if (retval)
 344                 return retval;
 345
 346         return 0;
 347 }
 348
 349 static const struct of_device_id rmi_spi_of_match[] = {
 350         { .compatible = "syna,rmi4-spi" },
 351         {},
 352 };
 353 MODULE_DEVICE_TABLE(of, rmi_spi_of_match);
 354 #else
 355 static inline int rmi_spi_of_probe(struct spi_device *spi,
 356                                 struct rmi_device_platform_data *pdata)
 357 {
 358         return -ENODEV;
 359 }
 360 #endif
 361
 362 static void rmi_spi_unregister_transport(void *data)
 363 {
 364         struct rmi_spi_xport *rmi_spi = data;
 365
 366         rmi_unregister_transport_device(&rmi_spi->xport);
 367 }
 368
 369 static int rmi_spi_probe(struct spi_device *spi)
 370 {
 371         struct rmi_spi_xport *rmi_spi;
 372         struct rmi_device_platform_data *pdata;
 373         struct rmi_device_platform_data *spi_pdata = spi->dev.platform_data;
 374         int error;
 375
 376         if (spi->master->flags & SPI_MASTER_HALF_DUPLEX)
 377                 return -EINVAL;
 378
 379         rmi_spi = devm_kzalloc(&spi->dev, sizeof(struct rmi_spi_xport),
 380                         GFP_KERNEL);
 381         if (!rmi_spi)
 382                 return -ENOMEM;
 383
 384         pdata = &rmi_spi->xport.pdata;
 385
 386         if (spi->dev.of_node) {
 387                 error = rmi_spi_of_probe(spi, pdata);
 388                 if (error)
 389                         return error;
 390         } else if (spi_pdata) {
 391                 *pdata = *spi_pdata;
 392         }
 393
 394         if (pdata->spi_data.bits_per_word)
 395                 spi->bits_per_word = pdata->spi_data.bits_per_word;
 396
 397         if (pdata->spi_data.mode)
 398                 spi->mode = pdata->spi_data.mode;
 399
 400         error = spi_setup(spi);
 401         if (error < 0) {
 402                 dev_err(&spi->dev, "spi_setup failed!\n");
 403                 return error;
 404         }
 405
 406         pdata->irq = spi->irq;
 407
 408         rmi_spi->spi = spi;
 409         mutex_init(&rmi_spi->page_mutex);
 410
 411         rmi_spi->xport.dev = &spi->dev;
 412         rmi_spi->xport.proto_name = "spi";
 413         rmi_spi->xport.ops = &rmi_spi_ops;
 414
 415         spi_set_drvdata(spi, rmi_spi);
 416
 417         error = rmi_spi_manage_pools(rmi_spi, RMI_SPI_DEFAULT_XFER_BUF_SIZE);
 418         if (error)
 419                 return error;
 420
 421         /*
 422          * Setting the page to zero will (a) make sure the PSR is in a
 423          * known state, and (b) make sure we can talk to the device.
 424          */
 425         error = rmi_set_page(rmi_spi, 0);
 426         if (error) {
 427                 dev_err(&spi->dev, "Failed to set page select to 0.\n");
 428                 return error;
 429         }
 430
 431         dev_info(&spi->dev, "registering SPI-connected sensor\n");
 432
 433         error = rmi_register_transport_device(&rmi_spi->xport);
 434         if (error) {
 435                 dev_err(&spi->dev, "failed to register sensor: %d\n", error);
 436                 return error;
 437         }
 438
 439         error = devm_add_action_or_reset(&spi->dev,
 440                                           rmi_spi_unregister_transport,
 441                                           rmi_spi);
 442         if (error)
 443                 return error;
 444
 445         return 0;
 446 }
 447
 448 #ifdef CONFIG_PM_SLEEP
 449 static int rmi_spi_suspend(struct device *dev)
 450 {
 451         struct spi_device *spi = to_spi_device(dev);
 452         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 453         int ret;
 454
 455         ret = rmi_driver_suspend(rmi_spi->xport.rmi_dev, true);
 456         if (ret)
 457                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 458
 459         return ret;
 460 }
 461
 462 static int rmi_spi_resume(struct device *dev)
 463 {
 464         struct spi_device *spi = to_spi_device(dev);
 465         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 466         int ret;
 467
 468         ret = rmi_driver_resume(rmi_spi->xport.rmi_dev, true);
 469         if (ret)
 470                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 471
 472         return ret;
 473 }
 474 #endif
 475
 476 #ifdef CONFIG_PM
 477 static int rmi_spi_runtime_suspend(struct device *dev)
 478 {
 479         struct spi_device *spi = to_spi_device(dev);
 480         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 481         int ret;
 482
 483         ret = rmi_driver_suspend(rmi_spi->xport.rmi_dev, false);
 484         if (ret)
 485                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 486
 487         return 0;
 488 }
 489
 490 static int rmi_spi_runtime_resume(struct device *dev)
 491 {
 492         struct spi_device *spi = to_spi_device(dev);
 493         struct rmi_spi_xport *rmi_spi = spi_get_drvdata(spi);
 494         int ret;
 495
 496         ret = rmi_driver_resume(rmi_spi->xport.rmi_dev, false);
 497         if (ret)
 498                 dev_warn(dev, "Failed to resume device: %d\n", ret);
 499
 500         return 0;
 501 }
 502 #endif
 503
 504 static const struct dev_pm_ops rmi_spi_pm = {
 505         SET_SYSTEM_SLEEP_PM_OPS(rmi_spi_suspend, rmi_spi_resume)
 506         SET_RUNTIME_PM_OPS(rmi_spi_runtime_suspend, rmi_spi_runtime_resume,
 507                            NULL)
 508 };
 509
 510 static const struct spi_device_id rmi_id[] = {
 511         { "rmi4_spi", 0 },
 512         { }
 513 };
 514 MODULE_DEVICE_TABLE(spi, rmi_id);
 515
 516 static struct spi_driver rmi_spi_driver = {
 517         .driver = {
 518                 .name   = "rmi4_spi",
 519                 .pm     = &rmi_spi_pm,
 520                 .of_match_table = of_match_ptr(rmi_spi_of_match),
 521         },
 522         .id_table       = rmi_id,
 523         .probe          = rmi_spi_probe,
 524 };
 525
 526 module_spi_driver(rmi_spi_driver);
 527
 528 MODULE_AUTHOR("Christopher Heiny <cheiny@synaptics.com>");
 529 MODULE_AUTHOR("Andrew Duggan <aduggan@synaptics.com>");
 530 MODULE_DESCRIPTION("RMI SPI driver");
 531 MODULE_LICENSE("GPL");