1/* 2 * Copyright (c) 2006 Ben Dooks 3 * Copyright 2006-2009 Simtec Electronics 4 * Ben Dooks <ben@simtec.co.uk> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10*/ 11 12#include <linux/spinlock.h> 13#include <linux/interrupt.h> 14#include <linux/delay.h> 15#include <linux/errno.h> 16#include <linux/err.h> 17#include <linux/clk.h> 18#include <linux/platform_device.h> 19#include <linux/gpio.h> 20#include <linux/io.h> 21#include <linux/slab.h> 22 23#include <linux/spi/spi.h> 24#include <linux/spi/spi_bitbang.h> 25#include <linux/spi/s3c24xx.h> 26#include <linux/module.h> 27 28#include <plat/regs-spi.h> 29 30#include <asm/fiq.h> 31 32#include "spi-s3c24xx-fiq.h" 33 34/** 35 * s3c24xx_spi_devstate - per device data 36 * @hz: Last frequency calculated for @sppre field. 37 * @mode: Last mode setting for the @spcon field. 38 * @spcon: Value to write to the SPCON register. 39 * @sppre: Value to write to the SPPRE register. 40 */ 41struct s3c24xx_spi_devstate { 42 unsigned int hz; 43 unsigned int mode; 44 u8 spcon; 45 u8 sppre; 46}; 47 48enum spi_fiq_mode { 49 FIQ_MODE_NONE = 0, 50 FIQ_MODE_TX = 1, 51 FIQ_MODE_RX = 2, 52 FIQ_MODE_TXRX = 3, 53}; 54 55struct s3c24xx_spi { 56 /* bitbang has to be first */ 57 struct spi_bitbang bitbang; 58 struct completion done; 59 60 void __iomem *regs; 61 int irq; 62 int len; 63 int count; 64 65 struct fiq_handler fiq_handler; 66 enum spi_fiq_mode fiq_mode; 67 unsigned char fiq_inuse; 68 unsigned char fiq_claimed; 69 70 void (*set_cs)(struct s3c2410_spi_info *spi, 71 int cs, int pol); 72 73 /* data buffers */ 74 const unsigned char *tx; 75 unsigned char *rx; 76 77 struct clk *clk; 78 struct spi_master *master; 79 struct spi_device *curdev; 80 struct device *dev; 81 struct s3c2410_spi_info *pdata; 82}; 83 84#define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT) 85#define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP) 86 87static inline struct s3c24xx_spi *to_hw(struct spi_device *sdev) 88{ 89 return spi_master_get_devdata(sdev->master); 90} 91 92static void s3c24xx_spi_gpiocs(struct s3c2410_spi_info *spi, int cs, int pol) 93{ 94 gpio_set_value(spi->pin_cs, pol); 95} 96 97static void s3c24xx_spi_chipsel(struct spi_device *spi, int value) 98{ 99 struct s3c24xx_spi_devstate *cs = spi->controller_state; 100 struct s3c24xx_spi *hw = to_hw(spi); 101 unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0; 102 103 /* change the chipselect state and the state of the spi engine clock */ 104 105 switch (value) { 106 case BITBANG_CS_INACTIVE: 107 hw->set_cs(hw->pdata, spi->chip_select, cspol^1); 108 writeb(cs->spcon, hw->regs + S3C2410_SPCON); 109 break; 110 111 case BITBANG_CS_ACTIVE: 112 writeb(cs->spcon | S3C2410_SPCON_ENSCK, 113 hw->regs + S3C2410_SPCON); 114 hw->set_cs(hw->pdata, spi->chip_select, cspol); 115 break; 116 } 117} 118 119static int s3c24xx_spi_update_state(struct spi_device *spi, 120 struct spi_transfer *t) 121{ 122 struct s3c24xx_spi *hw = to_hw(spi); 123 struct s3c24xx_spi_devstate *cs = spi->controller_state; 124 unsigned int hz; 125 unsigned int div; 126 unsigned long clk; 127 128 hz = t ? t->speed_hz : spi->max_speed_hz; 129 130 if (!hz) 131 hz = spi->max_speed_hz; 132 133 if (spi->mode != cs->mode) { 134 u8 spcon = SPCON_DEFAULT | S3C2410_SPCON_ENSCK; 135 136 if (spi->mode & SPI_CPHA) 137 spcon |= S3C2410_SPCON_CPHA_FMTB; 138 139 if (spi->mode & SPI_CPOL) 140 spcon |= S3C2410_SPCON_CPOL_HIGH; 141 142 cs->mode = spi->mode; 143 cs->spcon = spcon; 144 } 145 146 if (cs->hz != hz) { 147 clk = clk_get_rate(hw->clk); 148 div = DIV_ROUND_UP(clk, hz * 2) - 1; 149 150 if (div > 255) 151 div = 255; 152 153 dev_dbg(&spi->dev, "pre-scaler=%d (wanted %d, got %ld)\n", 154 div, hz, clk / (2 * (div + 1))); 155 156 cs->hz = hz; 157 cs->sppre = div; 158 } 159 160 return 0; 161} 162 163static int s3c24xx_spi_setupxfer(struct spi_device *spi, 164 struct spi_transfer *t) 165{ 166 struct s3c24xx_spi_devstate *cs = spi->controller_state; 167 struct s3c24xx_spi *hw = to_hw(spi); 168 int ret; 169 170 ret = s3c24xx_spi_update_state(spi, t); 171 if (!ret) 172 writeb(cs->sppre, hw->regs + S3C2410_SPPRE); 173 174 return ret; 175} 176 177static int s3c24xx_spi_setup(struct spi_device *spi) 178{ 179 struct s3c24xx_spi_devstate *cs = spi->controller_state; 180 struct s3c24xx_spi *hw = to_hw(spi); 181 int ret; 182 183 /* allocate settings on the first call */ 184 if (!cs) { 185 cs = devm_kzalloc(&spi->dev, 186 sizeof(struct s3c24xx_spi_devstate), 187 GFP_KERNEL); 188 if (!cs) 189 return -ENOMEM; 190 191 cs->spcon = SPCON_DEFAULT; 192 cs->hz = -1; 193 spi->controller_state = cs; 194 } 195 196 /* initialise the state from the device */ 197 ret = s3c24xx_spi_update_state(spi, NULL); 198 if (ret) 199 return ret; 200 201 spin_lock(&hw->bitbang.lock); 202 if (!hw->bitbang.busy) { 203 hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE); 204 /* need to ndelay for 0.5 clocktick ? */ 205 } 206 spin_unlock(&hw->bitbang.lock); 207 208 return 0; 209} 210 211static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count) 212{ 213 return hw->tx ? hw->tx[count] : 0; 214} 215 216#ifdef CONFIG_SPI_S3C24XX_FIQ 217/* Support for FIQ based pseudo-DMA to improve the transfer speed. 218 * 219 * This code uses the assembly helper in spi_s3c24xx_spi.S which is 220 * used by the FIQ core to move data between main memory and the peripheral 221 * block. Since this is code running on the processor, there is no problem 222 * with cache coherency of the buffers, so we can use any buffer we like. 223 */ 224 225/** 226 * struct spi_fiq_code - FIQ code and header 227 * @length: The length of the code fragment, excluding this header. 228 * @ack_offset: The offset from @data to the word to place the IRQ ACK bit at. 229 * @data: The code itself to install as a FIQ handler. 230 */ 231struct spi_fiq_code { 232 u32 length; 233 u32 ack_offset; 234 u8 data[0]; 235}; 236 237extern struct spi_fiq_code s3c24xx_spi_fiq_txrx; 238extern struct spi_fiq_code s3c24xx_spi_fiq_tx; 239extern struct spi_fiq_code s3c24xx_spi_fiq_rx; 240 241/** 242 * ack_bit - turn IRQ into IRQ acknowledgement bit 243 * @irq: The interrupt number 244 * 245 * Returns the bit to write to the interrupt acknowledge register. 246 */ 247static inline u32 ack_bit(unsigned int irq) 248{ 249 return 1 << (irq - IRQ_EINT0); 250} 251 252/** 253 * s3c24xx_spi_tryfiq - attempt to claim and setup FIQ for transfer 254 * @hw: The hardware state. 255 * 256 * Claim the FIQ handler (only one can be active at any one time) and 257 * then setup the correct transfer code for this transfer. 258 * 259 * This call updates all the necessary state information if successful, 260 * so the caller does not need to do anything more than start the transfer 261 * as normal, since the IRQ will have been re-routed to the FIQ handler. 262*/ 263static void s3c24xx_spi_tryfiq(struct s3c24xx_spi *hw) 264{ 265 struct pt_regs regs; 266 enum spi_fiq_mode mode; 267 struct spi_fiq_code *code; 268 int ret; 269 270 if (!hw->fiq_claimed) { 271 /* try and claim fiq if we haven't got it, and if not 272 * then return and simply use another transfer method */ 273 274 ret = claim_fiq(&hw->fiq_handler); 275 if (ret) 276 return; 277 } 278 279 if (hw->tx && !hw->rx) 280 mode = FIQ_MODE_TX; 281 else if (hw->rx && !hw->tx) 282 mode = FIQ_MODE_RX; 283 else 284 mode = FIQ_MODE_TXRX; 285 286 regs.uregs[fiq_rspi] = (long)hw->regs; 287 regs.uregs[fiq_rrx] = (long)hw->rx; 288 regs.uregs[fiq_rtx] = (long)hw->tx + 1; 289 regs.uregs[fiq_rcount] = hw->len - 1; 290 regs.uregs[fiq_rirq] = (long)S3C24XX_VA_IRQ; 291 292 set_fiq_regs(®s); 293 294 if (hw->fiq_mode != mode) { 295 u32 *ack_ptr; 296 297 hw->fiq_mode = mode; 298 299 switch (mode) { 300 case FIQ_MODE_TX: 301 code = &s3c24xx_spi_fiq_tx; 302 break; 303 case FIQ_MODE_RX: 304 code = &s3c24xx_spi_fiq_rx; 305 break; 306 case FIQ_MODE_TXRX: 307 code = &s3c24xx_spi_fiq_txrx; 308 break; 309 default: 310 code = NULL; 311 } 312 313 BUG_ON(!code); 314 315 ack_ptr = (u32 *)&code->data[code->ack_offset]; 316 *ack_ptr = ack_bit(hw->irq); 317 318 set_fiq_handler(&code->data, code->length); 319 } 320 321 s3c24xx_set_fiq(hw->irq, true); 322 323 hw->fiq_mode = mode; 324 hw->fiq_inuse = 1; 325} 326 327/** 328 * s3c24xx_spi_fiqop - FIQ core code callback 329 * @pw: Data registered with the handler 330 * @release: Whether this is a release or a return. 331 * 332 * Called by the FIQ code when another module wants to use the FIQ, so 333 * return whether we are currently using this or not and then update our 334 * internal state. 335 */ 336static int s3c24xx_spi_fiqop(void *pw, int release) 337{ 338 struct s3c24xx_spi *hw = pw; 339 int ret = 0; 340 341 if (release) { 342 if (hw->fiq_inuse) 343 ret = -EBUSY; 344 345 /* note, we do not need to unroute the FIQ, as the FIQ 346 * vector code de-routes it to signal the end of transfer */ 347 348 hw->fiq_mode = FIQ_MODE_NONE; 349 hw->fiq_claimed = 0; 350 } else { 351 hw->fiq_claimed = 1; 352 } 353 354 return ret; 355} 356 357/** 358 * s3c24xx_spi_initfiq - setup the information for the FIQ core 359 * @hw: The hardware state. 360 * 361 * Setup the fiq_handler block to pass to the FIQ core. 362 */ 363static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *hw) 364{ 365 hw->fiq_handler.dev_id = hw; 366 hw->fiq_handler.name = dev_name(hw->dev); 367 hw->fiq_handler.fiq_op = s3c24xx_spi_fiqop; 368} 369 370/** 371 * s3c24xx_spi_usefiq - return if we should be using FIQ. 372 * @hw: The hardware state. 373 * 374 * Return true if the platform data specifies whether this channel is 375 * allowed to use the FIQ. 376 */ 377static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *hw) 378{ 379 return hw->pdata->use_fiq; 380} 381 382/** 383 * s3c24xx_spi_usingfiq - return if channel is using FIQ 384 * @spi: The hardware state. 385 * 386 * Return whether the channel is currently using the FIQ (separate from 387 * whether the FIQ is claimed). 388 */ 389static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *spi) 390{ 391 return spi->fiq_inuse; 392} 393#else 394 395static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *s) { } 396static inline void s3c24xx_spi_tryfiq(struct s3c24xx_spi *s) { } 397static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *s) { return false; } 398static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *s) { return false; } 399 400#endif /* CONFIG_SPI_S3C24XX_FIQ */ 401 402static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t) 403{ 404 struct s3c24xx_spi *hw = to_hw(spi); 405 406 hw->tx = t->tx_buf; 407 hw->rx = t->rx_buf; 408 hw->len = t->len; 409 hw->count = 0; 410 411 init_completion(&hw->done); 412 413 hw->fiq_inuse = 0; 414 if (s3c24xx_spi_usefiq(hw) && t->len >= 3) 415 s3c24xx_spi_tryfiq(hw); 416 417 /* send the first byte */ 418 writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT); 419 420 wait_for_completion(&hw->done); 421 return hw->count; 422} 423 424static irqreturn_t s3c24xx_spi_irq(int irq, void *dev) 425{ 426 struct s3c24xx_spi *hw = dev; 427 unsigned int spsta = readb(hw->regs + S3C2410_SPSTA); 428 unsigned int count = hw->count; 429 430 if (spsta & S3C2410_SPSTA_DCOL) { 431 dev_dbg(hw->dev, "data-collision\n"); 432 complete(&hw->done); 433 goto irq_done; 434 } 435 436 if (!(spsta & S3C2410_SPSTA_READY)) { 437 dev_dbg(hw->dev, "spi not ready for tx?\n"); 438 complete(&hw->done); 439 goto irq_done; 440 } 441 442 if (!s3c24xx_spi_usingfiq(hw)) { 443 hw->count++; 444 445 if (hw->rx) 446 hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT); 447 448 count++; 449 450 if (count < hw->len) 451 writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT); 452 else 453 complete(&hw->done); 454 } else { 455 hw->count = hw->len; 456 hw->fiq_inuse = 0; 457 458 if (hw->rx) 459 hw->rx[hw->len-1] = readb(hw->regs + S3C2410_SPRDAT); 460 461 complete(&hw->done); 462 } 463 464 irq_done: 465 return IRQ_HANDLED; 466} 467 468static void s3c24xx_spi_initialsetup(struct s3c24xx_spi *hw) 469{ 470 /* for the moment, permanently enable the clock */ 471 472 clk_enable(hw->clk); 473 474 /* program defaults into the registers */ 475 476 writeb(0xff, hw->regs + S3C2410_SPPRE); 477 writeb(SPPIN_DEFAULT, hw->regs + S3C2410_SPPIN); 478 writeb(SPCON_DEFAULT, hw->regs + S3C2410_SPCON); 479 480 if (hw->pdata) { 481 if (hw->set_cs == s3c24xx_spi_gpiocs) 482 gpio_direction_output(hw->pdata->pin_cs, 1); 483 484 if (hw->pdata->gpio_setup) 485 hw->pdata->gpio_setup(hw->pdata, 1); 486 } 487} 488 489static int s3c24xx_spi_probe(struct platform_device *pdev) 490{ 491 struct s3c2410_spi_info *pdata; 492 struct s3c24xx_spi *hw; 493 struct spi_master *master; 494 struct resource *res; 495 int err = 0; 496 497 master = spi_alloc_master(&pdev->dev, sizeof(struct s3c24xx_spi)); 498 if (master == NULL) { 499 dev_err(&pdev->dev, "No memory for spi_master\n"); 500 return -ENOMEM; 501 } 502 503 hw = spi_master_get_devdata(master); 504 memset(hw, 0, sizeof(struct s3c24xx_spi)); 505 506 hw->master = master; 507 hw->pdata = pdata = dev_get_platdata(&pdev->dev); 508 hw->dev = &pdev->dev; 509 510 if (pdata == NULL) { 511 dev_err(&pdev->dev, "No platform data supplied\n"); 512 err = -ENOENT; 513 goto err_no_pdata; 514 } 515 516 platform_set_drvdata(pdev, hw); 517 init_completion(&hw->done); 518 519 /* initialise fiq handler */ 520 521 s3c24xx_spi_initfiq(hw); 522 523 /* setup the master state. */ 524 525 /* the spi->mode bits understood by this driver: */ 526 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; 527 528 master->num_chipselect = hw->pdata->num_cs; 529 master->bus_num = pdata->bus_num; 530 master->bits_per_word_mask = SPI_BPW_MASK(8); 531 532 /* setup the state for the bitbang driver */ 533 534 hw->bitbang.master = hw->master; 535 hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer; 536 hw->bitbang.chipselect = s3c24xx_spi_chipsel; 537 hw->bitbang.txrx_bufs = s3c24xx_spi_txrx; 538 539 hw->master->setup = s3c24xx_spi_setup; 540 541 dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang); 542 543 /* find and map our resources */ 544 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 545 hw->regs = devm_ioremap_resource(&pdev->dev, res); 546 if (IS_ERR(hw->regs)) { 547 err = PTR_ERR(hw->regs); 548 goto err_no_pdata; 549 } 550 551 hw->irq = platform_get_irq(pdev, 0); 552 if (hw->irq < 0) { 553 dev_err(&pdev->dev, "No IRQ specified\n"); 554 err = -ENOENT; 555 goto err_no_pdata; 556 } 557 558 err = devm_request_irq(&pdev->dev, hw->irq, s3c24xx_spi_irq, 0, 559 pdev->name, hw); 560 if (err) { 561 dev_err(&pdev->dev, "Cannot claim IRQ\n"); 562 goto err_no_pdata; 563 } 564 565 hw->clk = devm_clk_get(&pdev->dev, "spi"); 566 if (IS_ERR(hw->clk)) { 567 dev_err(&pdev->dev, "No clock for device\n"); 568 err = PTR_ERR(hw->clk); 569 goto err_no_pdata; 570 } 571 572 /* setup any gpio we can */ 573 574 if (!pdata->set_cs) { 575 if (pdata->pin_cs < 0) { 576 dev_err(&pdev->dev, "No chipselect pin\n"); 577 err = -EINVAL; 578 goto err_register; 579 } 580 581 err = devm_gpio_request(&pdev->dev, pdata->pin_cs, 582 dev_name(&pdev->dev)); 583 if (err) { 584 dev_err(&pdev->dev, "Failed to get gpio for cs\n"); 585 goto err_register; 586 } 587 588 hw->set_cs = s3c24xx_spi_gpiocs; 589 gpio_direction_output(pdata->pin_cs, 1); 590 } else 591 hw->set_cs = pdata->set_cs; 592 593 s3c24xx_spi_initialsetup(hw); 594 595 /* register our spi controller */ 596 597 err = spi_bitbang_start(&hw->bitbang); 598 if (err) { 599 dev_err(&pdev->dev, "Failed to register SPI master\n"); 600 goto err_register; 601 } 602 603 return 0; 604 605 err_register: 606 clk_disable(hw->clk); 607 608 err_no_pdata: 609 spi_master_put(hw->master); 610 return err; 611} 612 613static int s3c24xx_spi_remove(struct platform_device *dev) 614{ 615 struct s3c24xx_spi *hw = platform_get_drvdata(dev); 616 617 spi_bitbang_stop(&hw->bitbang); 618 clk_disable(hw->clk); 619 spi_master_put(hw->master); 620 return 0; 621} 622 623 624#ifdef CONFIG_PM 625 626static int s3c24xx_spi_suspend(struct device *dev) 627{ 628 struct s3c24xx_spi *hw = dev_get_drvdata(dev); 629 int ret; 630 631 ret = spi_master_suspend(hw->master); 632 if (ret) 633 return ret; 634 635 if (hw->pdata && hw->pdata->gpio_setup) 636 hw->pdata->gpio_setup(hw->pdata, 0); 637 638 clk_disable(hw->clk); 639 return 0; 640} 641 642static int s3c24xx_spi_resume(struct device *dev) 643{ 644 struct s3c24xx_spi *hw = dev_get_drvdata(dev); 645 646 s3c24xx_spi_initialsetup(hw); 647 return spi_master_resume(hw->master); 648} 649 650static const struct dev_pm_ops s3c24xx_spi_pmops = { 651 .suspend = s3c24xx_spi_suspend, 652 .resume = s3c24xx_spi_resume, 653}; 654 655#define S3C24XX_SPI_PMOPS &s3c24xx_spi_pmops 656#else 657#define S3C24XX_SPI_PMOPS NULL 658#endif /* CONFIG_PM */ 659 660MODULE_ALIAS("platform:s3c2410-spi"); 661static struct platform_driver s3c24xx_spi_driver = { 662 .probe = s3c24xx_spi_probe, 663 .remove = s3c24xx_spi_remove, 664 .driver = { 665 .name = "s3c2410-spi", 666 .pm = S3C24XX_SPI_PMOPS, 667 }, 668}; 669module_platform_driver(s3c24xx_spi_driver); 670 671MODULE_DESCRIPTION("S3C24XX SPI Driver"); 672MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>"); 673MODULE_LICENSE("GPL"); 674