drivers/spi/spi-omap-uwire.c

   1 /*
   2  * MicroWire interface driver for OMAP
   3  *
   4  * Copyright 2003 MontaVista Software Inc. <source@mvista.com>
   5  *
   6  * Ported to 2.6 OMAP uwire interface.
   7  * Copyright (C) 2004 Texas Instruments.
   8  *
   9  * Generalization patches by Juha Yrjola <juha.yrjola@nokia.com>
  10  *
  11  * Copyright (C) 2005 David Brownell (ported to 2.6 SPI interface)
  12  * Copyright (C) 2006 Nokia
  13  *
  14  * Many updates by Imre Deak <imre.deak@nokia.com>
  15  *
  16  * This program is free software; you can redistribute it and/or modify it
  17  * under the terms of the GNU General Public License as published by the
  18  * Free Software Foundation; either version 2 of the License, or (at your
  19  * option) any later version.
  20  *
  21  * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
  22  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  27  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  28  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  */
  32 #include <linux/kernel.h>
  33 #include <linux/init.h>
  34 #include <linux/delay.h>
  35 #include <linux/platform_device.h>
  36 #include <linux/interrupt.h>
  37 #include <linux/err.h>
  38 #include <linux/clk.h>
  39 #include <linux/slab.h>
  40 #include <linux/device.h>
  41
  42 #include <linux/spi/spi.h>
  43 #include <linux/spi/spi_bitbang.h>
  44 #include <linux/module.h>
  45 #include <linux/io.h>
  46
  47 #include <mach/hardware.h>
  48 #include <asm/mach-types.h>
  49
  50 #include <mach/mux.h>
  51
  52 #include <mach/omap7xx.h>       /* OMAP7XX_IO_CONF registers */
  53
  54
  55 /* FIXME address is now a platform device resource,
  56  * and irqs should show there too...
  57  */
  58 #define UWIRE_BASE_PHYS         0xFFFB3000
  59
  60 /* uWire Registers: */
  61 #define UWIRE_IO_SIZE 0x20
  62 #define UWIRE_TDR     0x00
  63 #define UWIRE_RDR     0x00
  64 #define UWIRE_CSR     0x01
  65 #define UWIRE_SR1     0x02
  66 #define UWIRE_SR2     0x03
  67 #define UWIRE_SR3     0x04
  68 #define UWIRE_SR4     0x05
  69 #define UWIRE_SR5     0x06
  70
  71 /* CSR bits */
  72 #define RDRB    (1 << 15)
  73 #define CSRB    (1 << 14)
  74 #define START   (1 << 13)
  75 #define CS_CMD  (1 << 12)
  76
  77 /* SR1 or SR2 bits */
  78 #define UWIRE_READ_FALLING_EDGE         0x0001
  79 #define UWIRE_READ_RISING_EDGE          0x0000
  80 #define UWIRE_WRITE_FALLING_EDGE        0x0000
  81 #define UWIRE_WRITE_RISING_EDGE         0x0002
  82 #define UWIRE_CS_ACTIVE_LOW             0x0000
  83 #define UWIRE_CS_ACTIVE_HIGH            0x0004
  84 #define UWIRE_FREQ_DIV_2                0x0000
  85 #define UWIRE_FREQ_DIV_4                0x0008
  86 #define UWIRE_FREQ_DIV_8                0x0010
  87 #define UWIRE_CHK_READY                 0x0020
  88 #define UWIRE_CLK_INVERTED              0x0040
  89
  90
  91 struct uwire_spi {
  92         struct spi_bitbang      bitbang;
  93         struct clk              *ck;
  94 };
  95
  96 struct uwire_state {
  97         unsigned        div1_idx;
  98 };
  99
 100 /* REVISIT compile time constant for idx_shift? */
 101 /*
 102  * Or, put it in a structure which is used throughout the driver;
 103  * that avoids having to issue two loads for each bit of static data.
 104  */
 105 static unsigned int uwire_idx_shift;
 106 static void __iomem *uwire_base;
 107
 108 static inline void uwire_write_reg(int idx, u16 val)
 109 {
 110         __raw_writew(val, uwire_base + (idx << uwire_idx_shift));
 111 }
 112
 113 static inline u16 uwire_read_reg(int idx)
 114 {
 115         return __raw_readw(uwire_base + (idx << uwire_idx_shift));
 116 }
 117
 118 static inline void omap_uwire_configure_mode(u8 cs, unsigned long flags)
 119 {
 120         u16     w, val = 0;
 121         int     shift, reg;
 122
 123         if (flags & UWIRE_CLK_INVERTED)
 124                 val ^= 0x03;
 125         val = flags & 0x3f;
 126         if (cs & 1)
 127                 shift = 6;
 128         else
 129                 shift = 0;
 130         if (cs <= 1)
 131                 reg = UWIRE_SR1;
 132         else
 133                 reg = UWIRE_SR2;
 134
 135         w = uwire_read_reg(reg);
 136         w &= ~(0x3f << shift);
 137         w |= val << shift;
 138         uwire_write_reg(reg, w);
 139 }
 140
 141 static int wait_uwire_csr_flag(u16 mask, u16 val, int might_not_catch)
 142 {
 143         u16 w;
 144         int c = 0;
 145         unsigned long max_jiffies = jiffies + HZ;
 146
 147         for (;;) {
 148                 w = uwire_read_reg(UWIRE_CSR);
 149                 if ((w & mask) == val)
 150                         break;
 151                 if (time_after(jiffies, max_jiffies)) {
 152                         printk(KERN_ERR "%s: timeout. reg=%#06x "
 153                                         "mask=%#06x val=%#06x\n",
 154                                __func__, w, mask, val);
 155                         return -1;
 156                 }
 157                 c++;
 158                 if (might_not_catch && c > 64)
 159                         break;
 160         }
 161         return 0;
 162 }
 163
 164 static void uwire_set_clk1_div(int div1_idx)
 165 {
 166         u16 w;
 167
 168         w = uwire_read_reg(UWIRE_SR3);
 169         w &= ~(0x03 << 1);
 170         w |= div1_idx << 1;
 171         uwire_write_reg(UWIRE_SR3, w);
 172 }
 173
 174 static void uwire_chipselect(struct spi_device *spi, int value)
 175 {
 176         struct  uwire_state *ust = spi->controller_state;
 177         u16     w;
 178         int     old_cs;
 179
 180
 181         BUG_ON(wait_uwire_csr_flag(CSRB, 0, 0));
 182
 183         w = uwire_read_reg(UWIRE_CSR);
 184         old_cs = (w >> 10) & 0x03;
 185         if (value == BITBANG_CS_INACTIVE || old_cs != spi->chip_select) {
 186                 /* Deselect this CS, or the previous CS */
 187                 w &= ~CS_CMD;
 188                 uwire_write_reg(UWIRE_CSR, w);
 189         }
 190         /* activate specfied chipselect */
 191         if (value == BITBANG_CS_ACTIVE) {
 192                 uwire_set_clk1_div(ust->div1_idx);
 193                 /* invert clock? */
 194                 if (spi->mode & SPI_CPOL)
 195                         uwire_write_reg(UWIRE_SR4, 1);
 196                 else
 197                         uwire_write_reg(UWIRE_SR4, 0);
 198
 199                 w = spi->chip_select << 10;
 200                 w |= CS_CMD;
 201                 uwire_write_reg(UWIRE_CSR, w);
 202         }
 203 }
 204
 205 static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t)
 206 {
 207         unsigned        len = t->len;
 208         unsigned        bits = t->bits_per_word;
 209         unsigned        bytes;
 210         u16             val, w;
 211         int             status = 0;
 212
 213         if (!t->tx_buf && !t->rx_buf)
 214                 return 0;
 215
 216         w = spi->chip_select << 10;
 217         w |= CS_CMD;
 218
 219         if (t->tx_buf) {
 220                 const u8        *buf = t->tx_buf;
 221
 222                 /* NOTE:  DMA could be used for TX transfers */
 223
 224                 /* write one or two bytes at a time */
 225                 while (len >= 1) {
 226                         /* tx bit 15 is first sent; we byteswap multibyte words
 227                          * (msb-first) on the way out from memory.
 228                          */
 229                         val = *buf++;
 230                         if (bits > 8) {
 231                                 bytes = 2;
 232                                 val |= *buf++ << 8;
 233                         } else
 234                                 bytes = 1;
 235                         val <<= 16 - bits;
 236
 237 #ifdef  VERBOSE
 238                         pr_debug("%s: write-%d =%04x\n",
 239                                         dev_name(&spi->dev), bits, val);
 240 #endif
 241                         if (wait_uwire_csr_flag(CSRB, 0, 0))
 242                                 goto eio;
 243
 244                         uwire_write_reg(UWIRE_TDR, val);
 245
 246                         /* start write */
 247                         val = START | w | (bits << 5);
 248
 249                         uwire_write_reg(UWIRE_CSR, val);
 250                         len -= bytes;
 251
 252                         /* Wait till write actually starts.
 253                          * This is needed with MPU clock 60+ MHz.
 254                          * REVISIT: we may not have time to catch it...
 255                          */
 256                         if (wait_uwire_csr_flag(CSRB, CSRB, 1))
 257                                 goto eio;
 258
 259                         status += bytes;
 260                 }
 261
 262                 /* REVISIT:  save this for later to get more i/o overlap */
 263                 if (wait_uwire_csr_flag(CSRB, 0, 0))
 264                         goto eio;
 265
 266         } else if (t->rx_buf) {
 267                 u8              *buf = t->rx_buf;
 268
 269                 /* read one or two bytes at a time */
 270                 while (len) {
 271                         if (bits > 8) {
 272                                 bytes = 2;
 273                         } else
 274                                 bytes = 1;
 275
 276                         /* start read */
 277                         val = START | w | (bits << 0);
 278                         uwire_write_reg(UWIRE_CSR, val);
 279                         len -= bytes;
 280
 281                         /* Wait till read actually starts */
 282                         (void) wait_uwire_csr_flag(CSRB, CSRB, 1);
 283
 284                         if (wait_uwire_csr_flag(RDRB | CSRB,
 285                                                 RDRB, 0))
 286                                 goto eio;
 287
 288                         /* rx bit 0 is last received; multibyte words will
 289                          * be properly byteswapped on the way to memory.
 290                          */
 291                         val = uwire_read_reg(UWIRE_RDR);
 292                         val &= (1 << bits) - 1;
 293                         *buf++ = (u8) val;
 294                         if (bytes == 2)
 295                                 *buf++ = val >> 8;
 296                         status += bytes;
 297 #ifdef  VERBOSE
 298                         pr_debug("%s: read-%d =%04x\n",
 299                                         dev_name(&spi->dev), bits, val);
 300 #endif
 301
 302                 }
 303         }
 304         return status;
 305 eio:
 306         return -EIO;
 307 }
 308
 309 static int uwire_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 310 {
 311         struct uwire_state      *ust = spi->controller_state;
 312         struct uwire_spi        *uwire;
 313         unsigned                flags = 0;
 314         unsigned                hz;
 315         unsigned long           rate;
 316         int                     div1_idx;
 317         int                     div1;
 318         int                     div2;
 319         int                     status;
 320
 321         uwire = spi_master_get_devdata(spi->master);
 322
 323         /* mode 0..3, clock inverted separately;
 324          * standard nCS signaling;
 325          * don't treat DI=high as "not ready"
 326          */
 327         if (spi->mode & SPI_CS_HIGH)
 328                 flags |= UWIRE_CS_ACTIVE_HIGH;
 329
 330         if (spi->mode & SPI_CPOL)
 331                 flags |= UWIRE_CLK_INVERTED;
 332
 333         switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
 334         case SPI_MODE_0:
 335         case SPI_MODE_3:
 336                 flags |= UWIRE_WRITE_FALLING_EDGE | UWIRE_READ_RISING_EDGE;
 337                 break;
 338         case SPI_MODE_1:
 339         case SPI_MODE_2:
 340                 flags |= UWIRE_WRITE_RISING_EDGE | UWIRE_READ_FALLING_EDGE;
 341                 break;
 342         }
 343
 344         /* assume it's already enabled */
 345         rate = clk_get_rate(uwire->ck);
 346
 347         if (t != NULL)
 348                 hz = t->speed_hz;
 349         else
 350                 hz = spi->max_speed_hz;
 351
 352         if (!hz) {
 353                 pr_debug("%s: zero speed?\n", dev_name(&spi->dev));
 354                 status = -EINVAL;
 355                 goto done;
 356         }
 357
 358         /* F_INT = mpu_xor_clk / DIV1 */
 359         for (div1_idx = 0; div1_idx < 4; div1_idx++) {
 360                 switch (div1_idx) {
 361                 case 0:
 362                         div1 = 2;
 363                         break;
 364                 case 1:
 365                         div1 = 4;
 366                         break;
 367                 case 2:
 368                         div1 = 7;
 369                         break;
 370                 default:
 371                 case 3:
 372                         div1 = 10;
 373                         break;
 374                 }
 375                 div2 = (rate / div1 + hz - 1) / hz;
 376                 if (div2 <= 8)
 377                         break;
 378         }
 379         if (div1_idx == 4) {
 380                 pr_debug("%s: lowest clock %ld, need %d\n",
 381                         dev_name(&spi->dev), rate / 10 / 8, hz);
 382                 status = -EDOM;
 383                 goto done;
 384         }
 385
 386         /* we have to cache this and reset in uwire_chipselect as this is a
 387          * global parameter and another uwire device can change it under
 388          * us */
 389         ust->div1_idx = div1_idx;
 390         uwire_set_clk1_div(div1_idx);
 391
 392         rate /= div1;
 393
 394         switch (div2) {
 395         case 0:
 396         case 1:
 397         case 2:
 398                 flags |= UWIRE_FREQ_DIV_2;
 399                 rate /= 2;
 400                 break;
 401         case 3:
 402         case 4:
 403                 flags |= UWIRE_FREQ_DIV_4;
 404                 rate /= 4;
 405                 break;
 406         case 5:
 407         case 6:
 408         case 7:
 409         case 8:
 410                 flags |= UWIRE_FREQ_DIV_8;
 411                 rate /= 8;
 412                 break;
 413         }
 414         omap_uwire_configure_mode(spi->chip_select, flags);
 415         pr_debug("%s: uwire flags %02x, armxor %lu KHz, SCK %lu KHz\n",
 416                         __func__, flags,
 417                         clk_get_rate(uwire->ck) / 1000,
 418                         rate / 1000);
 419         status = 0;
 420 done:
 421         return status;
 422 }
 423
 424 static int uwire_setup(struct spi_device *spi)
 425 {
 426         struct uwire_state *ust = spi->controller_state;
 427
 428         if (ust == NULL) {
 429                 ust = kzalloc(sizeof(*ust), GFP_KERNEL);
 430                 if (ust == NULL)
 431                         return -ENOMEM;
 432                 spi->controller_state = ust;
 433         }
 434
 435         return uwire_setup_transfer(spi, NULL);
 436 }
 437
 438 static void uwire_cleanup(struct spi_device *spi)
 439 {
 440         kfree(spi->controller_state);
 441 }
 442
 443 static void uwire_off(struct uwire_spi *uwire)
 444 {
 445         uwire_write_reg(UWIRE_SR3, 0);
 446         clk_disable_unprepare(uwire->ck);
 447         spi_master_put(uwire->bitbang.master);
 448 }
 449
 450 static int uwire_probe(struct platform_device *pdev)
 451 {
 452         struct spi_master       *master;
 453         struct uwire_spi        *uwire;
 454         int                     status;
 455
 456         master = spi_alloc_master(&pdev->dev, sizeof *uwire);
 457         if (!master)
 458                 return -ENODEV;
 459
 460         uwire = spi_master_get_devdata(master);
 461
 462         uwire_base = devm_ioremap(&pdev->dev, UWIRE_BASE_PHYS, UWIRE_IO_SIZE);
 463         if (!uwire_base) {
 464                 dev_dbg(&pdev->dev, "can't ioremap UWIRE\n");
 465                 spi_master_put(master);
 466                 return -ENOMEM;
 467         }
 468
 469         platform_set_drvdata(pdev, uwire);
 470
 471         uwire->ck = devm_clk_get(&pdev->dev, "fck");
 472         if (IS_ERR(uwire->ck)) {
 473                 status = PTR_ERR(uwire->ck);
 474                 dev_dbg(&pdev->dev, "no functional clock?\n");
 475                 spi_master_put(master);
 476                 return status;
 477         }
 478         clk_prepare_enable(uwire->ck);
 479
 480         if (cpu_is_omap7xx())
 481                 uwire_idx_shift = 1;
 482         else
 483                 uwire_idx_shift = 2;
 484
 485         uwire_write_reg(UWIRE_SR3, 1);
 486
 487         /* the spi->mode bits understood by this driver: */
 488         master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
 489         master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
 490         master->flags = SPI_MASTER_HALF_DUPLEX;
 491
 492         master->bus_num = 2;    /* "official" */
 493         master->num_chipselect = 4;
 494         master->setup = uwire_setup;
 495         master->cleanup = uwire_cleanup;
 496
 497         uwire->bitbang.master = master;
 498         uwire->bitbang.chipselect = uwire_chipselect;
 499         uwire->bitbang.setup_transfer = uwire_setup_transfer;
 500         uwire->bitbang.txrx_bufs = uwire_txrx;
 501
 502         status = spi_bitbang_start(&uwire->bitbang);
 503         if (status < 0) {
 504                 uwire_off(uwire);
 505         }
 506         return status;
 507 }
 508
 509 static int uwire_remove(struct platform_device *pdev)
 510 {
 511         struct uwire_spi        *uwire = platform_get_drvdata(pdev);
 512
 513         // FIXME remove all child devices, somewhere ...
 514
 515         spi_bitbang_stop(&uwire->bitbang);
 516         uwire_off(uwire);
 517         return 0;
 518 }
 519
 520 /* work with hotplug and coldplug */
 521 MODULE_ALIAS("platform:omap_uwire");
 522
 523 static struct platform_driver uwire_driver = {
 524         .driver = {
 525                 .name           = "omap_uwire",
 526         },
 527         .probe = uwire_probe,
 528         .remove = uwire_remove,
 529         // suspend ... unuse ck
 530         // resume ... use ck
 531 };
 532
 533 static int __init omap_uwire_init(void)
 534 {
 535         /* FIXME move these into the relevant board init code. also, include
 536          * H3 support; it uses tsc2101 like H2 (on a different chipselect).
 537          */
 538
 539         if (machine_is_omap_h2()) {
 540                 /* defaults: W21 SDO, U18 SDI, V19 SCL */
 541                 omap_cfg_reg(N14_1610_UWIRE_CS0);
 542                 omap_cfg_reg(N15_1610_UWIRE_CS1);
 543         }
 544         if (machine_is_omap_perseus2()) {
 545                 /* configure pins: MPU_UW_nSCS1, MPU_UW_SDO, MPU_UW_SCLK */
 546                 int val = omap_readl(OMAP7XX_IO_CONF_9) & ~0x00EEE000;
 547                 omap_writel(val | 0x00AAA000, OMAP7XX_IO_CONF_9);
 548         }
 549
 550         return platform_driver_register(&uwire_driver);
 551 }
 552
 553 static void __exit omap_uwire_exit(void)
 554 {
 555         platform_driver_unregister(&uwire_driver);
 556 }
 557
 558 subsys_initcall(omap_uwire_init);
 559 module_exit(omap_uwire_exit);
 560
 561 MODULE_LICENSE("GPL");
 562