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 ret = rmi_spi_manage_pools(rmi_spi, len); 152 if (ret < 0) 153 return ret; 154 } 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 #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"); 534