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