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   1 /*
   2  * OMAP7xx SPI 100k controller driver
   3  * Author: Fabrice Crohas <fcrohas@gmail.com>
   4  * from original omap1_mcspi driver
   5  *
   6  * Copyright (C) 2005, 2006 Nokia Corporation
   7  * Author:      Samuel Ortiz <samuel.ortiz@nokia.com> and
   8  *              Juha Yrj�l� <juha.yrjola@nokia.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  *
  24  */
  25 #include <linux/kernel.h>
  26 #include <linux/init.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/module.h>
  29 #include <linux/device.h>
  30 #include <linux/delay.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/err.h>
  33 #include <linux/clk.h>
  34 #include <linux/io.h>
  35 #include <linux/gpio.h>
  36
  37 #include <linux/spi/spi.h>
  38
  39 #include <plat/clock.h>
  40
  41 #define OMAP1_SPI100K_MAX_FREQ          48000000
  42
  43 #define ICR_SPITAS      (OMAP7XX_ICR_BASE + 0x12)
  44
  45 #define SPI_SETUP1      0x00
  46 #define SPI_SETUP2      0x02
  47 #define SPI_CTRL        0x04
  48 #define SPI_STATUS      0x06
  49 #define SPI_TX_LSB      0x08
  50 #define SPI_TX_MSB      0x0a
  51 #define SPI_RX_LSB      0x0c
  52 #define SPI_RX_MSB      0x0e
  53
  54 #define SPI_SETUP1_INT_READ_ENABLE      (1UL << 5)
  55 #define SPI_SETUP1_INT_WRITE_ENABLE     (1UL << 4)
  56 #define SPI_SETUP1_CLOCK_DIVISOR(x)     ((x) << 1)
  57 #define SPI_SETUP1_CLOCK_ENABLE         (1UL << 0)
  58
  59 #define SPI_SETUP2_ACTIVE_EDGE_FALLING  (0UL << 0)
  60 #define SPI_SETUP2_ACTIVE_EDGE_RISING   (1UL << 0)
  61 #define SPI_SETUP2_NEGATIVE_LEVEL       (0UL << 5)
  62 #define SPI_SETUP2_POSITIVE_LEVEL       (1UL << 5)
  63 #define SPI_SETUP2_LEVEL_TRIGGER        (0UL << 10)
  64 #define SPI_SETUP2_EDGE_TRIGGER         (1UL << 10)
  65
  66 #define SPI_CTRL_SEN(x)                 ((x) << 7)
  67 #define SPI_CTRL_WORD_SIZE(x)           (((x) - 1) << 2)
  68 #define SPI_CTRL_WR                     (1UL << 1)
  69 #define SPI_CTRL_RD                     (1UL << 0)
  70
  71 #define SPI_STATUS_WE                   (1UL << 1)
  72 #define SPI_STATUS_RD                   (1UL << 0)
  73
  74 #define WRITE 0
  75 #define READ  1
  76
  77
  78 /* use PIO for small transfers, avoiding DMA setup/teardown overhead and
  79  * cache operations; better heuristics consider wordsize and bitrate.
  80  */
  81 #define DMA_MIN_BYTES                   8
  82
  83 #define SPI_RUNNING     0
  84 #define SPI_SHUTDOWN    1
  85
  86 struct omap1_spi100k {
  87         struct work_struct      work;
  88
  89         /* lock protects queue and registers */
  90         spinlock_t              lock;
  91         struct list_head        msg_queue;
  92         struct spi_master       *master;
  93         struct clk              *ick;
  94         struct clk              *fck;
  95
  96         /* Virtual base address of the controller */
  97         void __iomem            *base;
  98
  99         /* State of the SPI */
 100         unsigned int            state;
 101 };
 102
 103 struct omap1_spi100k_cs {
 104         void __iomem            *base;
 105         int                     word_len;
 106 };
 107
 108 static struct workqueue_struct *omap1_spi100k_wq;
 109
 110 #define MOD_REG_BIT(val, mask, set) do { \
 111         if (set) \
 112                 val |= mask; \
 113         else \
 114                 val &= ~mask; \
 115 } while (0)
 116
 117 static void spi100k_enable_clock(struct spi_master *master)
 118 {
 119         unsigned int val;
 120         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 121
 122         /* enable SPI */
 123         val = readw(spi100k->base + SPI_SETUP1);
 124         val |= SPI_SETUP1_CLOCK_ENABLE;
 125         writew(val, spi100k->base + SPI_SETUP1);
 126 }
 127
 128 static void spi100k_disable_clock(struct spi_master *master)
 129 {
 130         unsigned int val;
 131         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 132
 133         /* disable SPI */
 134         val = readw(spi100k->base + SPI_SETUP1);
 135         val &= ~SPI_SETUP1_CLOCK_ENABLE;
 136         writew(val, spi100k->base + SPI_SETUP1);
 137 }
 138
 139 static void spi100k_write_data(struct spi_master *master, int len, int data)
 140 {
 141         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 142
 143         /* write 16-bit word */
 144         spi100k_enable_clock(master);
 145         writew( data , spi100k->base + SPI_TX_MSB);
 146
 147         writew(SPI_CTRL_SEN(0) |
 148                SPI_CTRL_WORD_SIZE(len) |
 149                SPI_CTRL_WR,
 150                spi100k->base + SPI_CTRL);
 151
 152         /* Wait for bit ack send change */
 153         while((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_WE) != SPI_STATUS_WE);
 154         udelay(1000);
 155
 156         spi100k_disable_clock(master);
 157 }
 158
 159 static int spi100k_read_data(struct spi_master *master, int len)
 160 {
 161         int dataH,dataL;
 162         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 163
 164         spi100k_enable_clock(master);
 165         writew(SPI_CTRL_SEN(0) |
 166                SPI_CTRL_WORD_SIZE(len) |
 167                SPI_CTRL_RD,
 168                spi100k->base + SPI_CTRL);
 169
 170         while((readw(spi100k->base + SPI_STATUS) & SPI_STATUS_RD) != SPI_STATUS_RD);
 171         udelay(1000);
 172
 173         dataL = readw(spi100k->base + SPI_RX_LSB);
 174         dataH = readw(spi100k->base + SPI_RX_MSB);
 175         spi100k_disable_clock(master);
 176
 177         return dataL;
 178 }
 179
 180 static void spi100k_open(struct spi_master *master)
 181 {
 182         /* get control of SPI */
 183         struct omap1_spi100k *spi100k = spi_master_get_devdata(master);
 184
 185         writew(SPI_SETUP1_INT_READ_ENABLE |
 186                SPI_SETUP1_INT_WRITE_ENABLE |
 187                SPI_SETUP1_CLOCK_DIVISOR(0), spi100k->base + SPI_SETUP1);
 188
 189         /* configure clock and interrupts */
 190         writew(SPI_SETUP2_ACTIVE_EDGE_FALLING |
 191                SPI_SETUP2_NEGATIVE_LEVEL |
 192                SPI_SETUP2_LEVEL_TRIGGER, spi100k->base + SPI_SETUP2);
 193 }
 194
 195 static void omap1_spi100k_force_cs(struct omap1_spi100k *spi100k, int enable)
 196 {
 197         if (enable)
 198                 writew(0x05fc, spi100k->base + SPI_CTRL);
 199         else
 200                 writew(0x05fd, spi100k->base + SPI_CTRL);
 201 }
 202
 203 static unsigned
 204 omap1_spi100k_txrx_pio(struct spi_device *spi, struct spi_transfer *xfer)
 205 {
 206         struct omap1_spi100k    *spi100k;
 207         struct omap1_spi100k_cs *cs = spi->controller_state;
 208         unsigned int            count, c;
 209         int                     word_len;
 210
 211         spi100k = spi_master_get_devdata(spi->master);
 212         count = xfer->len;
 213         c = count;
 214         word_len = cs->word_len;
 215
 216         /* RX_ONLY mode needs dummy data in TX reg */
 217         if (xfer->tx_buf == NULL)
 218                 spi100k_write_data(spi->master,word_len, 0);
 219
 220         if (word_len <= 8) {
 221                 u8              *rx;
 222                 const u8        *tx;
 223
 224                 rx = xfer->rx_buf;
 225                 tx = xfer->tx_buf;
 226                 do {
 227                         c-=1;
 228                         if (xfer->tx_buf != NULL)
 229                                 spi100k_write_data(spi->master,word_len, *tx);
 230                         if (xfer->rx_buf != NULL)
 231                                 *rx = spi100k_read_data(spi->master,word_len);
 232                 } while(c);
 233         } else if (word_len <= 16) {
 234                 u16             *rx;
 235                 const u16       *tx;
 236
 237                 rx = xfer->rx_buf;
 238                 tx = xfer->tx_buf;
 239                 do {
 240                         c-=2;
 241                         if (xfer->tx_buf != NULL)
 242                                 spi100k_write_data(spi->master,word_len, *tx++);
 243                         if (xfer->rx_buf != NULL)
 244                                 *rx++ = spi100k_read_data(spi->master,word_len);
 245                 } while(c);
 246         } else if (word_len <= 32) {
 247                 u32             *rx;
 248                 const u32       *tx;
 249
 250                 rx = xfer->rx_buf;
 251                 tx = xfer->tx_buf;
 252                 do {
 253                         c-=4;
 254                         if (xfer->tx_buf != NULL)
 255                                 spi100k_write_data(spi->master,word_len, *tx);
 256                         if (xfer->rx_buf != NULL)
 257                                 *rx = spi100k_read_data(spi->master,word_len);
 258                 } while(c);
 259         }
 260         return count - c;
 261 }
 262
 263 /* called only when no transfer is active to this device */
 264 static int omap1_spi100k_setup_transfer(struct spi_device *spi,
 265                 struct spi_transfer *t)
 266 {
 267         struct omap1_spi100k *spi100k = spi_master_get_devdata(spi->master);
 268         struct omap1_spi100k_cs *cs = spi->controller_state;
 269         u8 word_len = spi->bits_per_word;
 270
 271         if (t != NULL && t->bits_per_word)
 272                 word_len = t->bits_per_word;
 273         if (!word_len)
 274                 word_len = 8;
 275
 276         if (spi->bits_per_word > 32)
 277                 return -EINVAL;
 278         cs->word_len = word_len;
 279
 280         /* SPI init before transfer */
 281         writew(0x3e , spi100k->base + SPI_SETUP1);
 282         writew(0x00 , spi100k->base + SPI_STATUS);
 283         writew(0x3e , spi100k->base + SPI_CTRL);
 284
 285         return 0;
 286 }
 287
 288 /* the spi->mode bits understood by this driver: */
 289 #define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
 290
 291 static int omap1_spi100k_setup(struct spi_device *spi)
 292 {
 293         int                     ret;
 294         struct omap1_spi100k    *spi100k;
 295         struct omap1_spi100k_cs *cs = spi->controller_state;
 296
 297         if (spi->bits_per_word < 4 || spi->bits_per_word > 32) {
 298                  dev_dbg(&spi->dev, "setup: unsupported %d bit words\n",
 299                         spi->bits_per_word);
 300                  return -EINVAL;
 301         }
 302
 303         spi100k = spi_master_get_devdata(spi->master);
 304
 305         if (!cs) {
 306                 cs = kzalloc(sizeof *cs, GFP_KERNEL);
 307                 if (!cs)
 308                         return -ENOMEM;
 309                 cs->base = spi100k->base + spi->chip_select * 0x14;
 310                 spi->controller_state = cs;
 311         }
 312
 313         spi100k_open(spi->master);
 314
 315         clk_enable(spi100k->ick);
 316         clk_enable(spi100k->fck);
 317
 318         ret = omap1_spi100k_setup_transfer(spi, NULL);
 319
 320         clk_disable(spi100k->ick);
 321         clk_disable(spi100k->fck);
 322
 323         return ret;
 324 }
 325
 326 static void omap1_spi100k_work(struct work_struct *work)
 327 {
 328         struct omap1_spi100k    *spi100k;
 329         int status = 0;
 330
 331         spi100k = container_of(work, struct omap1_spi100k, work);
 332         spin_lock_irq(&spi100k->lock);
 333
 334         clk_enable(spi100k->ick);
 335         clk_enable(spi100k->fck);
 336
 337         /* We only enable one channel at a time -- the one whose message is
 338          * at the head of the queue -- although this controller would gladly
 339          * arbitrate among multiple channels.  This corresponds to "single
 340          * channel" master mode.  As a side effect, we need to manage the
 341          * chipselect with the FORCE bit ... CS != channel enable.
 342          */
 343          while (!list_empty(&spi100k->msg_queue)) {
 344                 struct spi_message              *m;
 345                 struct spi_device               *spi;
 346                 struct spi_transfer             *t = NULL;
 347                 int                             cs_active = 0;
 348                 struct omap1_spi100k_cs         *cs;
 349                 int                             par_override = 0;
 350
 351                 m = container_of(spi100k->msg_queue.next, struct spi_message,
 352                                  queue);
 353
 354                 list_del_init(&m->queue);
 355                 spin_unlock_irq(&spi100k->lock);
 356
 357                 spi = m->spi;
 358                 cs = spi->controller_state;
 359
 360                 list_for_each_entry(t, &m->transfers, transfer_list) {
 361                         if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
 362                                 status = -EINVAL;
 363                                 break;
 364                         }
 365                         if (par_override || t->speed_hz || t->bits_per_word) {
 366                                 par_override = 1;
 367                                 status = omap1_spi100k_setup_transfer(spi, t);
 368                                 if (status < 0)
 369                                         break;
 370                                 if (!t->speed_hz && !t->bits_per_word)
 371                                         par_override = 0;
 372                         }
 373
 374                         if (!cs_active) {
 375                                 omap1_spi100k_force_cs(spi100k, 1);
 376                                 cs_active = 1;
 377                         }
 378
 379                         if (t->len) {
 380                                 unsigned count;
 381
 382                                 /* RX_ONLY mode needs dummy data in TX reg */
 383                                 if (t->tx_buf == NULL)
 384                                         spi100k_write_data(spi->master, 8, 0);
 385
 386                                 count = omap1_spi100k_txrx_pio(spi, t);
 387                                 m->actual_length += count;
 388
 389                                 if (count != t->len) {
 390                                         status = -EIO;
 391                                         break;
 392                                 }
 393                         }
 394
 395                         if (t->delay_usecs)
 396                                 udelay(t->delay_usecs);
 397
 398                         /* ignore the "leave it on after last xfer" hint */
 399
 400                         if (t->cs_change) {
 401                                 omap1_spi100k_force_cs(spi100k, 0);
 402                                 cs_active = 0;
 403                         }
 404                 }
 405
 406                 /* Restore defaults if they were overriden */
 407                 if (par_override) {
 408                         par_override = 0;
 409                         status = omap1_spi100k_setup_transfer(spi, NULL);
 410                 }
 411
 412                 if (cs_active)
 413                         omap1_spi100k_force_cs(spi100k, 0);
 414
 415                 m->status = status;
 416                 m->complete(m->context);
 417
 418                 spin_lock_irq(&spi100k->lock);
 419         }
 420
 421         clk_disable(spi100k->ick);
 422         clk_disable(spi100k->fck);
 423         spin_unlock_irq(&spi100k->lock);
 424
 425         if (status < 0)
 426                 printk(KERN_WARNING "spi transfer failed with %d\n", status);
 427 }
 428
 429 static int omap1_spi100k_transfer(struct spi_device *spi, struct spi_message *m)
 430 {
 431         struct omap1_spi100k    *spi100k;
 432         unsigned long           flags;
 433         struct spi_transfer     *t;
 434
 435         m->actual_length = 0;
 436         m->status = -EINPROGRESS;
 437
 438         spi100k = spi_master_get_devdata(spi->master);
 439
 440         /* Don't accept new work if we're shutting down */
 441         if (spi100k->state == SPI_SHUTDOWN)
 442                 return -ESHUTDOWN;
 443
 444         /* reject invalid messages and transfers */
 445         if (list_empty(&m->transfers) || !m->complete)
 446                 return -EINVAL;
 447
 448         list_for_each_entry(t, &m->transfers, transfer_list) {
 449                 const void      *tx_buf = t->tx_buf;
 450                 void            *rx_buf = t->rx_buf;
 451                 unsigned        len = t->len;
 452
 453                 if (t->speed_hz > OMAP1_SPI100K_MAX_FREQ
 454                                 || (len && !(rx_buf || tx_buf))
 455                                 || (t->bits_per_word &&
 456                                         (  t->bits_per_word < 4
 457                                         || t->bits_per_word > 32))) {
 458                         dev_dbg(&spi->dev, "transfer: %d Hz, %d %s%s, %d bpw\n",
 459                                         t->speed_hz,
 460                                         len,
 461                                         tx_buf ? "tx" : "",
 462                                         rx_buf ? "rx" : "",
 463                                         t->bits_per_word);
 464                         return -EINVAL;
 465                 }
 466
 467                 if (t->speed_hz && t->speed_hz < OMAP1_SPI100K_MAX_FREQ/(1<<16)) {
 468                         dev_dbg(&spi->dev, "%d Hz max exceeds %d\n",
 469                                         t->speed_hz,
 470                                         OMAP1_SPI100K_MAX_FREQ/(1<<16));
 471                         return -EINVAL;
 472                 }
 473
 474         }
 475
 476         spin_lock_irqsave(&spi100k->lock, flags);
 477         list_add_tail(&m->queue, &spi100k->msg_queue);
 478         queue_work(omap1_spi100k_wq, &spi100k->work);
 479         spin_unlock_irqrestore(&spi100k->lock, flags);
 480
 481         return 0;
 482 }
 483
 484 static int __init omap1_spi100k_reset(struct omap1_spi100k *spi100k)
 485 {
 486         return 0;
 487 }
 488
 489 static int __devinit omap1_spi100k_probe(struct platform_device *pdev)
 490 {
 491         struct spi_master       *master;
 492         struct omap1_spi100k    *spi100k;
 493         int                     status = 0;
 494
 495         if (!pdev->id)
 496                 return -EINVAL;
 497
 498         master = spi_alloc_master(&pdev->dev, sizeof *spi100k);
 499         if (master == NULL) {
 500                 dev_dbg(&pdev->dev, "master allocation failed\n");
 501                 return -ENOMEM;
 502         }
 503
 504         if (pdev->id != -1)
 505                master->bus_num = pdev->id;
 506
 507         master->setup = omap1_spi100k_setup;
 508         master->transfer = omap1_spi100k_transfer;
 509         master->cleanup = NULL;
 510         master->num_chipselect = 2;
 511         master->mode_bits = MODEBITS;
 512
 513         dev_set_drvdata(&pdev->dev, master);
 514
 515         spi100k = spi_master_get_devdata(master);
 516         spi100k->master = master;
 517
 518         /*
 519          * The memory region base address is taken as the platform_data.
 520          * You should allocate this with ioremap() before initializing
 521          * the SPI.
 522          */
 523         spi100k->base = (void __iomem *) pdev->dev.platform_data;
 524
 525         INIT_WORK(&spi100k->work, omap1_spi100k_work);
 526
 527         spin_lock_init(&spi100k->lock);
 528         INIT_LIST_HEAD(&spi100k->msg_queue);
 529         spi100k->ick = clk_get(&pdev->dev, "ick");
 530         if (IS_ERR(spi100k->ick)) {
 531                 dev_dbg(&pdev->dev, "can't get spi100k_ick\n");
 532                 status = PTR_ERR(spi100k->ick);
 533                 goto err1;
 534         }
 535
 536         spi100k->fck = clk_get(&pdev->dev, "fck");
 537         if (IS_ERR(spi100k->fck)) {
 538                 dev_dbg(&pdev->dev, "can't get spi100k_fck\n");
 539                 status = PTR_ERR(spi100k->fck);
 540                 goto err2;
 541         }
 542
 543         if (omap1_spi100k_reset(spi100k) < 0)
 544                 goto err3;
 545
 546         status = spi_register_master(master);
 547         if (status < 0)
 548                 goto err3;
 549
 550         spi100k->state = SPI_RUNNING;
 551
 552         return status;
 553
 554 err3:
 555         clk_put(spi100k->fck);
 556 err2:
 557         clk_put(spi100k->ick);
 558 err1:
 559         spi_master_put(master);
 560         return status;
 561 }
 562
 563 static int __exit omap1_spi100k_remove(struct platform_device *pdev)
 564 {
 565         struct spi_master       *master;
 566         struct omap1_spi100k    *spi100k;
 567         struct resource         *r;
 568         unsigned                limit = 500;
 569         unsigned long           flags;
 570         int                     status = 0;
 571
 572         master = dev_get_drvdata(&pdev->dev);
 573         spi100k = spi_master_get_devdata(master);
 574
 575         spin_lock_irqsave(&spi100k->lock, flags);
 576
 577         spi100k->state = SPI_SHUTDOWN;
 578         while (!list_empty(&spi100k->msg_queue) && limit--) {
 579                 spin_unlock_irqrestore(&spi100k->lock, flags);
 580                 msleep(10);
 581                 spin_lock_irqsave(&spi100k->lock, flags);
 582         }
 583
 584         if (!list_empty(&spi100k->msg_queue))
 585                 status = -EBUSY;
 586
 587         spin_unlock_irqrestore(&spi100k->lock, flags);
 588
 589         if (status != 0)
 590                 return status;
 591
 592         clk_put(spi100k->fck);
 593         clk_put(spi100k->ick);
 594
 595         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 596
 597         spi_unregister_master(master);
 598
 599         return 0;
 600 }
 601
 602 static struct platform_driver omap1_spi100k_driver = {
 603         .driver = {
 604                 .name           = "omap1_spi100k",
 605                 .owner          = THIS_MODULE,
 606         },
 607         .remove         = __exit_p(omap1_spi100k_remove),
 608 };
 609
 610
 611 static int __init omap1_spi100k_init(void)
 612 {
 613         omap1_spi100k_wq = create_singlethread_workqueue(
 614                         omap1_spi100k_driver.driver.name);
 615
 616         if (omap1_spi100k_wq == NULL)
 617                 return -1;
 618
 619         return platform_driver_probe(&omap1_spi100k_driver, omap1_spi100k_probe);
 620 }
 621
 622 static void __exit omap1_spi100k_exit(void)
 623 {
 624         platform_driver_unregister(&omap1_spi100k_driver);
 625
 626         destroy_workqueue(omap1_spi100k_wq);
 627 }
 628
 629 module_init(omap1_spi100k_init);
 630 module_exit(omap1_spi100k_exit);
 631
 632 MODULE_DESCRIPTION("OMAP7xx SPI 100k controller driver");
 633 MODULE_AUTHOR("Fabrice Crohas <fcrohas@gmail.com>");
 634 MODULE_LICENSE("GPL");
 635