drivers/spi/spi-orion.c

   1 /*
   2  * Marvell Orion SPI controller driver
   3  *
   4  * Author: Shadi Ammouri <shadi@marvell.com>
   5  * Copyright (C) 2007-2008 Marvell Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/delay.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/err.h>
  17 #include <linux/io.h>
  18 #include <linux/spi/spi.h>
  19 #include <linux/spi/orion_spi.h>
  20 #include <linux/module.h>
  21 #include <asm/unaligned.h>
  22
  23 #define DRIVER_NAME                     "orion_spi"
  24
  25 #define ORION_NUM_CHIPSELECTS           1 /* only one slave is supported*/
  26 #define ORION_SPI_WAIT_RDY_MAX_LOOP     2000 /* in usec */
  27
  28 #define ORION_SPI_IF_CTRL_REG           0x00
  29 #define ORION_SPI_IF_CONFIG_REG         0x04
  30 #define ORION_SPI_DATA_OUT_REG          0x08
  31 #define ORION_SPI_DATA_IN_REG           0x0c
  32 #define ORION_SPI_INT_CAUSE_REG         0x10
  33
  34 #define ORION_SPI_IF_8_16_BIT_MODE      (1 << 5)
  35 #define ORION_SPI_CLK_PRESCALE_MASK     0x1F
  36
  37 struct orion_spi {
  38         struct work_struct      work;
  39
  40         /* Lock access to transfer list.        */
  41         spinlock_t              lock;
  42
  43         struct list_head        msg_queue;
  44         struct spi_master       *master;
  45         void __iomem            *base;
  46         unsigned int            max_speed;
  47         unsigned int            min_speed;
  48         struct orion_spi_info   *spi_info;
  49 };
  50
  51 static struct workqueue_struct *orion_spi_wq;
  52
  53 static inline void __iomem *spi_reg(struct orion_spi *orion_spi, u32 reg)
  54 {
  55         return orion_spi->base + reg;
  56 }
  57
  58 static inline void
  59 orion_spi_setbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
  60 {
  61         void __iomem *reg_addr = spi_reg(orion_spi, reg);
  62         u32 val;
  63
  64         val = readl(reg_addr);
  65         val |= mask;
  66         writel(val, reg_addr);
  67 }
  68
  69 static inline void
  70 orion_spi_clrbits(struct orion_spi *orion_spi, u32 reg, u32 mask)
  71 {
  72         void __iomem *reg_addr = spi_reg(orion_spi, reg);
  73         u32 val;
  74
  75         val = readl(reg_addr);
  76         val &= ~mask;
  77         writel(val, reg_addr);
  78 }
  79
  80 static int orion_spi_set_transfer_size(struct orion_spi *orion_spi, int size)
  81 {
  82         if (size == 16) {
  83                 orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
  84                                   ORION_SPI_IF_8_16_BIT_MODE);
  85         } else if (size == 8) {
  86                 orion_spi_clrbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
  87                                   ORION_SPI_IF_8_16_BIT_MODE);
  88         } else {
  89                 pr_debug("Bad bits per word value %d (only 8 or 16 are "
  90                          "allowed).\n", size);
  91                 return -EINVAL;
  92         }
  93
  94         return 0;
  95 }
  96
  97 static int orion_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
  98 {
  99         u32 tclk_hz;
 100         u32 rate;
 101         u32 prescale;
 102         u32 reg;
 103         struct orion_spi *orion_spi;
 104
 105         orion_spi = spi_master_get_devdata(spi->master);
 106
 107         tclk_hz = orion_spi->spi_info->tclk;
 108
 109         /*
 110          * the supported rates are: 4,6,8...30
 111          * round up as we look for equal or less speed
 112          */
 113         rate = DIV_ROUND_UP(tclk_hz, speed);
 114         rate = roundup(rate, 2);
 115
 116         /* check if requested speed is too small */
 117         if (rate > 30)
 118                 return -EINVAL;
 119
 120         if (rate < 4)
 121                 rate = 4;
 122
 123         /* Convert the rate to SPI clock divisor value. */
 124         prescale = 0x10 + rate/2;
 125
 126         reg = readl(spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
 127         reg = ((reg & ~ORION_SPI_CLK_PRESCALE_MASK) | prescale);
 128         writel(reg, spi_reg(orion_spi, ORION_SPI_IF_CONFIG_REG));
 129
 130         return 0;
 131 }
 132
 133 /*
 134  * called only when no transfer is active on the bus
 135  */
 136 static int
 137 orion_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 138 {
 139         struct orion_spi *orion_spi;
 140         unsigned int speed = spi->max_speed_hz;
 141         unsigned int bits_per_word = spi->bits_per_word;
 142         int     rc;
 143
 144         orion_spi = spi_master_get_devdata(spi->master);
 145
 146         if ((t != NULL) && t->speed_hz)
 147                 speed = t->speed_hz;
 148
 149         if ((t != NULL) && t->bits_per_word)
 150                 bits_per_word = t->bits_per_word;
 151
 152         rc = orion_spi_baudrate_set(spi, speed);
 153         if (rc)
 154                 return rc;
 155
 156         return orion_spi_set_transfer_size(orion_spi, bits_per_word);
 157 }
 158
 159 static void orion_spi_set_cs(struct orion_spi *orion_spi, int enable)
 160 {
 161         if (enable)
 162                 orion_spi_setbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
 163         else
 164                 orion_spi_clrbits(orion_spi, ORION_SPI_IF_CTRL_REG, 0x1);
 165 }
 166
 167 static inline int orion_spi_wait_till_ready(struct orion_spi *orion_spi)
 168 {
 169         int i;
 170
 171         for (i = 0; i < ORION_SPI_WAIT_RDY_MAX_LOOP; i++) {
 172                 if (readl(spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG)))
 173                         return 1;
 174                 else
 175                         udelay(1);
 176         }
 177
 178         return -1;
 179 }
 180
 181 static inline int
 182 orion_spi_write_read_8bit(struct spi_device *spi,
 183                           const u8 **tx_buf, u8 **rx_buf)
 184 {
 185         void __iomem *tx_reg, *rx_reg, *int_reg;
 186         struct orion_spi *orion_spi;
 187
 188         orion_spi = spi_master_get_devdata(spi->master);
 189         tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
 190         rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
 191         int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
 192
 193         /* clear the interrupt cause register */
 194         writel(0x0, int_reg);
 195
 196         if (tx_buf && *tx_buf)
 197                 writel(*(*tx_buf)++, tx_reg);
 198         else
 199                 writel(0, tx_reg);
 200
 201         if (orion_spi_wait_till_ready(orion_spi) < 0) {
 202                 dev_err(&spi->dev, "TXS timed out\n");
 203                 return -1;
 204         }
 205
 206         if (rx_buf && *rx_buf)
 207                 *(*rx_buf)++ = readl(rx_reg);
 208
 209         return 1;
 210 }
 211
 212 static inline int
 213 orion_spi_write_read_16bit(struct spi_device *spi,
 214                            const u16 **tx_buf, u16 **rx_buf)
 215 {
 216         void __iomem *tx_reg, *rx_reg, *int_reg;
 217         struct orion_spi *orion_spi;
 218
 219         orion_spi = spi_master_get_devdata(spi->master);
 220         tx_reg = spi_reg(orion_spi, ORION_SPI_DATA_OUT_REG);
 221         rx_reg = spi_reg(orion_spi, ORION_SPI_DATA_IN_REG);
 222         int_reg = spi_reg(orion_spi, ORION_SPI_INT_CAUSE_REG);
 223
 224         /* clear the interrupt cause register */
 225         writel(0x0, int_reg);
 226
 227         if (tx_buf && *tx_buf)
 228                 writel(__cpu_to_le16(get_unaligned((*tx_buf)++)), tx_reg);
 229         else
 230                 writel(0, tx_reg);
 231
 232         if (orion_spi_wait_till_ready(orion_spi) < 0) {
 233                 dev_err(&spi->dev, "TXS timed out\n");
 234                 return -1;
 235         }
 236
 237         if (rx_buf && *rx_buf)
 238                 put_unaligned(__le16_to_cpu(readl(rx_reg)), (*rx_buf)++);
 239
 240         return 1;
 241 }
 242
 243 static unsigned int
 244 orion_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
 245 {
 246         struct orion_spi *orion_spi;
 247         unsigned int count;
 248         int word_len;
 249
 250         orion_spi = spi_master_get_devdata(spi->master);
 251         word_len = spi->bits_per_word;
 252         count = xfer->len;
 253
 254         if (word_len == 8) {
 255                 const u8 *tx = xfer->tx_buf;
 256                 u8 *rx = xfer->rx_buf;
 257
 258                 do {
 259                         if (orion_spi_write_read_8bit(spi, &tx, &rx) < 0)
 260                                 goto out;
 261                         count--;
 262                 } while (count);
 263         } else if (word_len == 16) {
 264                 const u16 *tx = xfer->tx_buf;
 265                 u16 *rx = xfer->rx_buf;
 266
 267                 do {
 268                         if (orion_spi_write_read_16bit(spi, &tx, &rx) < 0)
 269                                 goto out;
 270                         count -= 2;
 271                 } while (count);
 272         }
 273
 274 out:
 275         return xfer->len - count;
 276 }
 277
 278
 279 static void orion_spi_work(struct work_struct *work)
 280 {
 281         struct orion_spi *orion_spi =
 282                 container_of(work, struct orion_spi, work);
 283
 284         spin_lock_irq(&orion_spi->lock);
 285         while (!list_empty(&orion_spi->msg_queue)) {
 286                 struct spi_message *m;
 287                 struct spi_device *spi;
 288                 struct spi_transfer *t = NULL;
 289                 int par_override = 0;
 290                 int status = 0;
 291                 int cs_active = 0;
 292
 293                 m = container_of(orion_spi->msg_queue.next, struct spi_message,
 294                                  queue);
 295
 296                 list_del_init(&m->queue);
 297                 spin_unlock_irq(&orion_spi->lock);
 298
 299                 spi = m->spi;
 300
 301                 /* Load defaults */
 302                 status = orion_spi_setup_transfer(spi, NULL);
 303
 304                 if (status < 0)
 305                         goto msg_done;
 306
 307                 list_for_each_entry(t, &m->transfers, transfer_list) {
 308                         if (par_override || t->speed_hz || t->bits_per_word) {
 309                                 par_override = 1;
 310                                 status = orion_spi_setup_transfer(spi, t);
 311                                 if (status < 0)
 312                                         break;
 313                                 if (!t->speed_hz && !t->bits_per_word)
 314                                         par_override = 0;
 315                         }
 316
 317                         if (!cs_active) {
 318                                 orion_spi_set_cs(orion_spi, 1);
 319                                 cs_active = 1;
 320                         }
 321
 322                         if (t->len)
 323                                 m->actual_length +=
 324                                         orion_spi_write_read(spi, t);
 325
 326                         if (t->delay_usecs)
 327                                 udelay(t->delay_usecs);
 328
 329                         if (t->cs_change) {
 330                                 orion_spi_set_cs(orion_spi, 0);
 331                                 cs_active = 0;
 332                         }
 333                 }
 334
 335 msg_done:
 336                 if (cs_active)
 337                         orion_spi_set_cs(orion_spi, 0);
 338
 339                 m->status = status;
 340                 m->complete(m->context);
 341
 342                 spin_lock_irq(&orion_spi->lock);
 343         }
 344
 345         spin_unlock_irq(&orion_spi->lock);
 346 }
 347
 348 static int __init orion_spi_reset(struct orion_spi *orion_spi)
 349 {
 350         /* Verify that the CS is deasserted */
 351         orion_spi_set_cs(orion_spi, 0);
 352
 353         return 0;
 354 }
 355
 356 static int orion_spi_setup(struct spi_device *spi)
 357 {
 358         struct orion_spi *orion_spi;
 359
 360         orion_spi = spi_master_get_devdata(spi->master);
 361
 362         /* Fix ac timing if required.   */
 363         if (orion_spi->spi_info->enable_clock_fix)
 364                 orion_spi_setbits(orion_spi, ORION_SPI_IF_CONFIG_REG,
 365                                   (1 << 14));
 366
 367         if ((spi->max_speed_hz == 0)
 368                         || (spi->max_speed_hz > orion_spi->max_speed))
 369                 spi->max_speed_hz = orion_spi->max_speed;
 370
 371         if (spi->max_speed_hz < orion_spi->min_speed) {
 372                 dev_err(&spi->dev, "setup: requested speed too low %d Hz\n",
 373                         spi->max_speed_hz);
 374                 return -EINVAL;
 375         }
 376
 377         /*
 378          * baudrate & width will be set orion_spi_setup_transfer
 379          */
 380         return 0;
 381 }
 382
 383 static int orion_spi_transfer(struct spi_device *spi, struct spi_message *m)
 384 {
 385         struct orion_spi *orion_spi;
 386         struct spi_transfer *t = NULL;
 387         unsigned long flags;
 388
 389         m->actual_length = 0;
 390         m->status = 0;
 391
 392         /* reject invalid messages and transfers */
 393         if (list_empty(&m->transfers) || !m->complete)
 394                 return -EINVAL;
 395
 396         orion_spi = spi_master_get_devdata(spi->master);
 397
 398         list_for_each_entry(t, &m->transfers, transfer_list) {
 399                 unsigned int bits_per_word = spi->bits_per_word;
 400
 401                 if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
 402                         dev_err(&spi->dev,
 403                                 "message rejected : "
 404                                 "invalid transfer data buffers\n");
 405                         goto msg_rejected;
 406                 }
 407
 408                 if (t->bits_per_word)
 409                         bits_per_word = t->bits_per_word;
 410
 411                 if ((bits_per_word != 8) && (bits_per_word != 16)) {
 412                         dev_err(&spi->dev,
 413                                 "message rejected : "
 414                                 "invalid transfer bits_per_word (%d bits)\n",
 415                                 bits_per_word);
 416                         goto msg_rejected;
 417                 }
 418                 /*make sure buffer length is even when working in 16 bit mode*/
 419                 if ((t->bits_per_word == 16) && (t->len & 1)) {
 420                         dev_err(&spi->dev,
 421                                 "message rejected : "
 422                                 "odd data length (%d) while in 16 bit mode\n",
 423                                 t->len);
 424                         goto msg_rejected;
 425                 }
 426
 427                 if (t->speed_hz && t->speed_hz < orion_spi->min_speed) {
 428                         dev_err(&spi->dev,
 429                                 "message rejected : "
 430                                 "device min speed (%d Hz) exceeds "
 431                                 "required transfer speed (%d Hz)\n",
 432                                 orion_spi->min_speed, t->speed_hz);
 433                         goto msg_rejected;
 434                 }
 435         }
 436
 437
 438         spin_lock_irqsave(&orion_spi->lock, flags);
 439         list_add_tail(&m->queue, &orion_spi->msg_queue);
 440         queue_work(orion_spi_wq, &orion_spi->work);
 441         spin_unlock_irqrestore(&orion_spi->lock, flags);
 442
 443         return 0;
 444 msg_rejected:
 445         /* Message rejected and not queued */
 446         m->status = -EINVAL;
 447         if (m->complete)
 448                 m->complete(m->context);
 449         return -EINVAL;
 450 }
 451
 452 static int __init orion_spi_probe(struct platform_device *pdev)
 453 {
 454         struct spi_master *master;
 455         struct orion_spi *spi;
 456         struct resource *r;
 457         struct orion_spi_info *spi_info;
 458         int status = 0;
 459
 460         spi_info = pdev->dev.platform_data;
 461
 462         master = spi_alloc_master(&pdev->dev, sizeof *spi);
 463         if (master == NULL) {
 464                 dev_dbg(&pdev->dev, "master allocation failed\n");
 465                 return -ENOMEM;
 466         }
 467
 468         if (pdev->id != -1)
 469                 master->bus_num = pdev->id;
 470
 471         /* we support only mode 0, and no options */
 472         master->mode_bits = 0;
 473
 474         master->setup = orion_spi_setup;
 475         master->transfer = orion_spi_transfer;
 476         master->num_chipselect = ORION_NUM_CHIPSELECTS;
 477
 478         dev_set_drvdata(&pdev->dev, master);
 479
 480         spi = spi_master_get_devdata(master);
 481         spi->master = master;
 482         spi->spi_info = spi_info;
 483
 484         spi->max_speed = DIV_ROUND_UP(spi_info->tclk, 4);
 485         spi->min_speed = DIV_ROUND_UP(spi_info->tclk, 30);
 486
 487         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 488         if (r == NULL) {
 489                 status = -ENODEV;
 490                 goto out;
 491         }
 492
 493         if (!request_mem_region(r->start, resource_size(r),
 494                                 dev_name(&pdev->dev))) {
 495                 status = -EBUSY;
 496                 goto out;
 497         }
 498         spi->base = ioremap(r->start, SZ_1K);
 499
 500         INIT_WORK(&spi->work, orion_spi_work);
 501
 502         spin_lock_init(&spi->lock);
 503         INIT_LIST_HEAD(&spi->msg_queue);
 504
 505         if (orion_spi_reset(spi) < 0)
 506                 goto out_rel_mem;
 507
 508         status = spi_register_master(master);
 509         if (status < 0)
 510                 goto out_rel_mem;
 511
 512         return status;
 513
 514 out_rel_mem:
 515         release_mem_region(r->start, resource_size(r));
 516
 517 out:
 518         spi_master_put(master);
 519         return status;
 520 }
 521
 522
 523 static int __exit orion_spi_remove(struct platform_device *pdev)
 524 {
 525         struct spi_master *master;
 526         struct orion_spi *spi;
 527         struct resource *r;
 528
 529         master = dev_get_drvdata(&pdev->dev);
 530         spi = spi_master_get_devdata(master);
 531
 532         cancel_work_sync(&spi->work);
 533
 534         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 535         release_mem_region(r->start, resource_size(r));
 536
 537         spi_unregister_master(master);
 538
 539         return 0;
 540 }
 541
 542 MODULE_ALIAS("platform:" DRIVER_NAME);
 543
 544 static struct platform_driver orion_spi_driver = {
 545         .driver = {
 546                 .name   = DRIVER_NAME,
 547                 .owner  = THIS_MODULE,
 548         },
 549         .remove         = __exit_p(orion_spi_remove),
 550 };
 551
 552 static int __init orion_spi_init(void)
 553 {
 554         orion_spi_wq = create_singlethread_workqueue(
 555                                 orion_spi_driver.driver.name);
 556         if (orion_spi_wq == NULL)
 557                 return -ENOMEM;
 558
 559         return platform_driver_probe(&orion_spi_driver, orion_spi_probe);
 560 }
 561 module_init(orion_spi_init);
 562
 563 static void __exit orion_spi_exit(void)
 564 {
 565         flush_workqueue(orion_spi_wq);
 566         platform_driver_unregister(&orion_spi_driver);
 567
 568         destroy_workqueue(orion_spi_wq);
 569 }
 570 module_exit(orion_spi_exit);
 571
 572 MODULE_DESCRIPTION("Orion SPI driver");
 573 MODULE_AUTHOR("Shadi Ammouri <shadi@marvell.com>");
 574 MODULE_LICENSE("GPL");