drivers/i2c/busses/i2c-sh7760.c

   1 /*
   2  * I2C bus driver for the SH7760 I2C Interfaces.
   3  *
   4  * (c) 2005-2008 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
   5  *
   6  * licensed under the terms outlined in the file COPYING.
   7  *
   8  */
   9
  10 #include <linux/completion.h>
  11 #include <linux/delay.h>
  12 #include <linux/err.h>
  13 #include <linux/i2c.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/ioport.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/slab.h>
  18 #include <linux/io.h>
  19 #include <linux/module.h>
  20
  21 #include <asm/clock.h>
  22 #include <asm/i2c-sh7760.h>
  23
  24 /* register offsets */
  25 #define I2CSCR          0x0             /* slave ctrl           */
  26 #define I2CMCR          0x4             /* master ctrl          */
  27 #define I2CSSR          0x8             /* slave status         */
  28 #define I2CMSR          0xC             /* master status        */
  29 #define I2CSIER         0x10            /* slave irq enable     */
  30 #define I2CMIER         0x14            /* master irq enable    */
  31 #define I2CCCR          0x18            /* clock dividers       */
  32 #define I2CSAR          0x1c            /* slave address        */
  33 #define I2CMAR          0x20            /* master address       */
  34 #define I2CRXTX         0x24            /* data port            */
  35 #define I2CFCR          0x28            /* fifo control         */
  36 #define I2CFSR          0x2C            /* fifo status          */
  37 #define I2CFIER         0x30            /* fifo irq enable      */
  38 #define I2CRFDR         0x34            /* rx fifo count        */
  39 #define I2CTFDR         0x38            /* tx fifo count        */
  40
  41 #define REGSIZE         0x3C
  42
  43 #define MCR_MDBS        0x80            /* non-fifo mode switch */
  44 #define MCR_FSCL        0x40            /* override SCL pin     */
  45 #define MCR_FSDA        0x20            /* override SDA pin     */
  46 #define MCR_OBPC        0x10            /* override pins        */
  47 #define MCR_MIE         0x08            /* master if enable     */
  48 #define MCR_TSBE        0x04
  49 #define MCR_FSB         0x02            /* force stop bit       */
  50 #define MCR_ESG         0x01            /* en startbit gen.     */
  51
  52 #define MSR_MNR         0x40            /* nack received        */
  53 #define MSR_MAL         0x20            /* arbitration lost     */
  54 #define MSR_MST         0x10            /* sent a stop          */
  55 #define MSR_MDE         0x08
  56 #define MSR_MDT         0x04
  57 #define MSR_MDR         0x02
  58 #define MSR_MAT         0x01            /* slave addr xfer done */
  59
  60 #define MIE_MNRE        0x40            /* nack irq en          */
  61 #define MIE_MALE        0x20            /* arblos irq en        */
  62 #define MIE_MSTE        0x10            /* stop irq en          */
  63 #define MIE_MDEE        0x08
  64 #define MIE_MDTE        0x04
  65 #define MIE_MDRE        0x02
  66 #define MIE_MATE        0x01            /* address sent irq en  */
  67
  68 #define FCR_RFRST       0x02            /* reset rx fifo        */
  69 #define FCR_TFRST       0x01            /* reset tx fifo        */
  70
  71 #define FSR_TEND        0x04            /* last byte sent       */
  72 #define FSR_RDF         0x02            /* rx fifo trigger      */
  73 #define FSR_TDFE        0x01            /* tx fifo empty        */
  74
  75 #define FIER_TEIE       0x04            /* tx fifo empty irq en */
  76 #define FIER_RXIE       0x02            /* rx fifo trig irq en  */
  77 #define FIER_TXIE       0x01            /* tx fifo trig irq en  */
  78
  79 #define FIFO_SIZE       16
  80
  81 struct cami2c {
  82         void __iomem *iobase;
  83         struct i2c_adapter adap;
  84
  85         /* message processing */
  86         struct i2c_msg  *msg;
  87 #define IDF_SEND        1
  88 #define IDF_RECV        2
  89 #define IDF_STOP        4
  90         int             flags;
  91
  92 #define IDS_DONE        1
  93 #define IDS_ARBLOST     2
  94 #define IDS_NACK        4
  95         int             status;
  96         struct completion xfer_done;
  97
  98         int irq;
  99         struct resource *ioarea;
 100 };
 101
 102 static inline void OUT32(struct cami2c *cam, int reg, unsigned long val)
 103 {
 104         __raw_writel(val, (unsigned long)cam->iobase + reg);
 105 }
 106
 107 static inline unsigned long IN32(struct cami2c *cam, int reg)
 108 {
 109         return __raw_readl((unsigned long)cam->iobase + reg);
 110 }
 111
 112 static irqreturn_t sh7760_i2c_irq(int irq, void *ptr)
 113 {
 114         struct cami2c *id = ptr;
 115         struct i2c_msg *msg = id->msg;
 116         char *data = msg->buf;
 117         unsigned long msr, fsr, fier, len;
 118
 119         msr = IN32(id, I2CMSR);
 120         fsr = IN32(id, I2CFSR);
 121
 122         /* arbitration lost */
 123         if (msr & MSR_MAL) {
 124                 OUT32(id, I2CMCR, 0);
 125                 OUT32(id, I2CSCR, 0);
 126                 OUT32(id, I2CSAR, 0);
 127                 id->status |= IDS_DONE | IDS_ARBLOST;
 128                 goto out;
 129         }
 130
 131         if (msr & MSR_MNR) {
 132                 /* NACK handling is very screwed up.  After receiving a
 133                  * NAK IRQ one has to wait a bit  before writing to any
 134                  * registers, or the ctl will lock up. After that delay
 135                  * do a normal i2c stop. Then wait at least 1 ms before
 136                  * attempting another transfer or ctl will stop working
 137                  */
 138                 udelay(100);    /* wait or risk ctl hang */
 139                 OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
 140                 OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
 141                 OUT32(id, I2CFIER, 0);
 142                 OUT32(id, I2CMIER, MIE_MSTE);
 143                 OUT32(id, I2CSCR, 0);
 144                 OUT32(id, I2CSAR, 0);
 145                 id->status |= IDS_NACK;
 146                 msr &= ~MSR_MAT;
 147                 fsr = 0;
 148                 /* In some cases the MST bit is also set. */
 149         }
 150
 151         /* i2c-stop was sent */
 152         if (msr & MSR_MST) {
 153                 id->status |= IDS_DONE;
 154                 goto out;
 155         }
 156
 157         /* i2c slave addr was sent; set to "normal" operation */
 158         if (msr & MSR_MAT)
 159                 OUT32(id, I2CMCR, MCR_MIE);
 160
 161         fier = IN32(id, I2CFIER);
 162
 163         if (fsr & FSR_RDF) {
 164                 len = IN32(id, I2CRFDR);
 165                 if (msg->len <= len) {
 166                         if (id->flags & IDF_STOP) {
 167                                 OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
 168                                 OUT32(id, I2CFIER, 0);
 169                                 /* manual says: wait >= 0.5 SCL times */
 170                                 udelay(5);
 171                                 /* next int should be MST */
 172                         } else {
 173                                 id->status |= IDS_DONE;
 174                                 /* keep the RDF bit: ctrl holds SCL low
 175                                  * until the setup for the next i2c_msg
 176                                  * clears this bit.
 177                                  */
 178                                 fsr &= ~FSR_RDF;
 179                         }
 180                 }
 181                 while (msg->len && len) {
 182                         *data++ = IN32(id, I2CRXTX);
 183                         msg->len--;
 184                         len--;
 185                 }
 186
 187                 if (msg->len) {
 188                         len = (msg->len >= FIFO_SIZE) ? FIFO_SIZE - 1
 189                                                       : msg->len - 1;
 190
 191                         OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xf) << 4));
 192                 }
 193
 194         } else if (id->flags & IDF_SEND) {
 195                 if ((fsr & FSR_TEND) && (msg->len < 1)) {
 196                         if (id->flags & IDF_STOP) {
 197                                 OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
 198                         } else {
 199                                 id->status |= IDS_DONE;
 200                                 /* keep the TEND bit: ctl holds SCL low
 201                                  * until the setup for the next i2c_msg
 202                                  * clears this bit.
 203                                  */
 204                                 fsr &= ~FSR_TEND;
 205                         }
 206                 }
 207                 if (fsr & FSR_TDFE) {
 208                         while (msg->len && (IN32(id, I2CTFDR) < FIFO_SIZE)) {
 209                                 OUT32(id, I2CRXTX, *data++);
 210                                 msg->len--;
 211                         }
 212
 213                         if (msg->len < 1) {
 214                                 fier &= ~FIER_TXIE;
 215                                 OUT32(id, I2CFIER, fier);
 216                         } else {
 217                                 len = (msg->len >= FIFO_SIZE) ? 2 : 0;
 218                                 OUT32(id, I2CFCR,
 219                                           FCR_RFRST | ((len & 3) << 2));
 220                         }
 221                 }
 222         }
 223 out:
 224         if (id->status & IDS_DONE) {
 225                 OUT32(id, I2CMIER, 0);
 226                 OUT32(id, I2CFIER, 0);
 227                 id->msg = NULL;
 228                 complete(&id->xfer_done);
 229         }
 230         /* clear status flags and ctrl resumes work */
 231         OUT32(id, I2CMSR, ~msr);
 232         OUT32(id, I2CFSR, ~fsr);
 233         OUT32(id, I2CSSR, 0);
 234
 235         return IRQ_HANDLED;
 236 }
 237
 238
 239 /* prepare and start a master receive operation */
 240 static void sh7760_i2c_mrecv(struct cami2c *id)
 241 {
 242         int len;
 243
 244         id->flags |= IDF_RECV;
 245
 246         /* set the slave addr reg; otherwise rcv wont work! */
 247         OUT32(id, I2CSAR, 0xfe);
 248         OUT32(id, I2CMAR, (id->msg->addr << 1) | 1);
 249
 250         /* adjust rx fifo trigger */
 251         if (id->msg->len >= FIFO_SIZE)
 252                 len = FIFO_SIZE - 1;    /* trigger at fifo full */
 253         else
 254                 len = id->msg->len - 1; /* trigger before all received */
 255
 256         OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
 257         OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xF) << 4));
 258
 259         OUT32(id, I2CMSR, 0);
 260         OUT32(id, I2CMCR, MCR_MIE | MCR_ESG);
 261         OUT32(id, I2CMIER, MIE_MNRE | MIE_MALE | MIE_MSTE | MIE_MATE);
 262         OUT32(id, I2CFIER, FIER_RXIE);
 263 }
 264
 265 /* prepare and start a master send operation */
 266 static void sh7760_i2c_msend(struct cami2c *id)
 267 {
 268         int len;
 269
 270         id->flags |= IDF_SEND;
 271
 272         /* set the slave addr reg; otherwise xmit wont work! */
 273         OUT32(id, I2CSAR, 0xfe);
 274         OUT32(id, I2CMAR, (id->msg->addr << 1) | 0);
 275
 276         /* adjust tx fifo trigger */
 277         if (id->msg->len >= FIFO_SIZE)
 278                 len = 2;        /* trig: 2 bytes left in TX fifo */
 279         else
 280                 len = 0;        /* trig: 8 bytes left in TX fifo */
 281
 282         OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
 283         OUT32(id, I2CFCR, FCR_RFRST | ((len & 3) << 2));
 284
 285         while (id->msg->len && IN32(id, I2CTFDR) < FIFO_SIZE) {
 286                 OUT32(id, I2CRXTX, *(id->msg->buf));
 287                 (id->msg->len)--;
 288                 (id->msg->buf)++;
 289         }
 290
 291         OUT32(id, I2CMSR, 0);
 292         OUT32(id, I2CMCR, MCR_MIE | MCR_ESG);
 293         OUT32(id, I2CFSR, 0);
 294         OUT32(id, I2CMIER, MIE_MNRE | MIE_MALE | MIE_MSTE | MIE_MATE);
 295         OUT32(id, I2CFIER, FIER_TEIE | (id->msg->len ? FIER_TXIE : 0));
 296 }
 297
 298 static inline int sh7760_i2c_busy_check(struct cami2c *id)
 299 {
 300         return (IN32(id, I2CMCR) & MCR_FSDA);
 301 }
 302
 303 static int sh7760_i2c_master_xfer(struct i2c_adapter *adap,
 304                                   struct i2c_msg *msgs,
 305                                   int num)
 306 {
 307         struct cami2c *id = adap->algo_data;
 308         int i, retr;
 309
 310         if (sh7760_i2c_busy_check(id)) {
 311                 dev_err(&adap->dev, "sh7760-i2c%d: bus busy!\n", adap->nr);
 312                 return -EBUSY;
 313         }
 314
 315         i = 0;
 316         while (i < num) {
 317                 retr = adap->retries;
 318 retry:
 319                 id->flags = ((i == (num-1)) ? IDF_STOP : 0);
 320                 id->status = 0;
 321                 id->msg = msgs;
 322                 init_completion(&id->xfer_done);
 323
 324                 if (msgs->flags & I2C_M_RD)
 325                         sh7760_i2c_mrecv(id);
 326                 else
 327                         sh7760_i2c_msend(id);
 328
 329                 wait_for_completion(&id->xfer_done);
 330
 331                 if (id->status == 0) {
 332                         num = -EIO;
 333                         break;
 334                 }
 335
 336                 if (id->status & IDS_NACK) {
 337                         /* wait a bit or i2c module stops working */
 338                         mdelay(1);
 339                         num = -EREMOTEIO;
 340                         break;
 341                 }
 342
 343                 if (id->status & IDS_ARBLOST) {
 344                         if (retr--) {
 345                                 mdelay(2);
 346                                 goto retry;
 347                         }
 348                         num = -EREMOTEIO;
 349                         break;
 350                 }
 351
 352                 msgs++;
 353                 i++;
 354         }
 355
 356         id->msg = NULL;
 357         id->flags = 0;
 358         id->status = 0;
 359
 360         OUT32(id, I2CMCR, 0);
 361         OUT32(id, I2CMSR, 0);
 362         OUT32(id, I2CMIER, 0);
 363         OUT32(id, I2CFIER, 0);
 364
 365         /* reset slave module registers too: master mode enables slave
 366          * module for receive ops (ack, data). Without this reset,
 367          * eternal bus activity might be reported after NACK / ARBLOST.
 368          */
 369         OUT32(id, I2CSCR, 0);
 370         OUT32(id, I2CSAR, 0);
 371         OUT32(id, I2CSSR, 0);
 372
 373         return num;
 374 }
 375
 376 static u32 sh7760_i2c_func(struct i2c_adapter *adap)
 377 {
 378         return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
 379 }
 380
 381 static const struct i2c_algorithm sh7760_i2c_algo = {
 382         .master_xfer    = sh7760_i2c_master_xfer,
 383         .functionality  = sh7760_i2c_func,
 384 };
 385
 386 /* calculate CCR register setting for a desired scl clock.  SCL clock is
 387  * derived from I2C module clock  (iclk)  which in turn is derived from
 388  * peripheral module clock (mclk, usually around 33MHz):
 389  * iclk = mclk/(CDF + 1).  iclk must be < 20MHz.
 390  * scl = iclk/(SCGD*8 + 20).
 391  */
 392 static int calc_CCR(unsigned long scl_hz)
 393 {
 394         struct clk *mclk;
 395         unsigned long mck, m1, dff, odff, iclk;
 396         signed char cdf, cdfm;
 397         int scgd, scgdm, scgds;
 398
 399         mclk = clk_get(NULL, "peripheral_clk");
 400         if (IS_ERR(mclk)) {
 401                 return PTR_ERR(mclk);
 402         } else {
 403                 mck = mclk->rate;
 404                 clk_put(mclk);
 405         }
 406
 407         odff = scl_hz;
 408         scgdm = cdfm = m1 = 0;
 409         for (cdf = 3; cdf >= 0; cdf--) {
 410                 iclk = mck / (1 + cdf);
 411                 if (iclk >= 20000000)
 412                         continue;
 413                 scgds = ((iclk / scl_hz) - 20) >> 3;
 414                 for (scgd = scgds; (scgd < 63) && scgd <= scgds + 1; scgd++) {
 415                         m1 = iclk / (20 + (scgd << 3));
 416                         dff = abs(scl_hz - m1);
 417                         if (dff < odff) {
 418                                 odff = dff;
 419                                 cdfm = cdf;
 420                                 scgdm = scgd;
 421                         }
 422                 }
 423         }
 424         /* fail if more than 25% off of requested SCL */
 425         if (odff > (scl_hz >> 2))
 426                 return -EINVAL;
 427
 428         /* create a CCR register value */
 429         return ((scgdm << 2) | cdfm);
 430 }
 431
 432 static int sh7760_i2c_probe(struct platform_device *pdev)
 433 {
 434         struct sh7760_i2c_platdata *pd;
 435         struct resource *res;
 436         struct cami2c *id;
 437         int ret;
 438
 439         pd = dev_get_platdata(&pdev->dev);
 440         if (!pd) {
 441                 dev_err(&pdev->dev, "no platform_data!\n");
 442                 ret = -ENODEV;
 443                 goto out0;
 444         }
 445
 446         id = kzalloc(sizeof(*id), GFP_KERNEL);
 447         if (!id) {
 448                 ret = -ENOMEM;
 449                 goto out0;
 450         }
 451
 452         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 453         if (!res) {
 454                 dev_err(&pdev->dev, "no mmio resources\n");
 455                 ret = -ENODEV;
 456                 goto out1;
 457         }
 458
 459         id->ioarea = request_mem_region(res->start, REGSIZE, pdev->name);
 460         if (!id->ioarea) {
 461                 dev_err(&pdev->dev, "mmio already reserved\n");
 462                 ret = -EBUSY;
 463                 goto out1;
 464         }
 465
 466         id->iobase = ioremap(res->start, REGSIZE);
 467         if (!id->iobase) {
 468                 dev_err(&pdev->dev, "cannot ioremap\n");
 469                 ret = -ENODEV;
 470                 goto out2;
 471         }
 472
 473         ret = platform_get_irq(pdev, 0);
 474         if (ret < 0)
 475                 goto out3;
 476         id->irq = ret;
 477
 478         id->adap.nr = pdev->id;
 479         id->adap.algo = &sh7760_i2c_algo;
 480         id->adap.class = I2C_CLASS_HWMON;
 481         id->adap.retries = 3;
 482         id->adap.algo_data = id;
 483         id->adap.dev.parent = &pdev->dev;
 484         snprintf(id->adap.name, sizeof(id->adap.name),
 485                 "SH7760 I2C at %08lx", (unsigned long)res->start);
 486
 487         OUT32(id, I2CMCR, 0);
 488         OUT32(id, I2CMSR, 0);
 489         OUT32(id, I2CMIER, 0);
 490         OUT32(id, I2CMAR, 0);
 491         OUT32(id, I2CSIER, 0);
 492         OUT32(id, I2CSAR, 0);
 493         OUT32(id, I2CSCR, 0);
 494         OUT32(id, I2CSSR, 0);
 495         OUT32(id, I2CFIER, 0);
 496         OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
 497         OUT32(id, I2CFSR, 0);
 498
 499         ret = calc_CCR(pd->speed_khz * 1000);
 500         if (ret < 0) {
 501                 dev_err(&pdev->dev, "invalid SCL clock: %dkHz\n",
 502                         pd->speed_khz);
 503                 goto out3;
 504         }
 505         OUT32(id, I2CCCR, ret);
 506
 507         if (request_irq(id->irq, sh7760_i2c_irq, 0,
 508                         SH7760_I2C_DEVNAME, id)) {
 509                 dev_err(&pdev->dev, "cannot get irq %d\n", id->irq);
 510                 ret = -EBUSY;
 511                 goto out3;
 512         }
 513
 514         ret = i2c_add_numbered_adapter(&id->adap);
 515         if (ret < 0)
 516                 goto out4;
 517
 518         platform_set_drvdata(pdev, id);
 519
 520         dev_info(&pdev->dev, "%d kHz mmio %08x irq %d\n",
 521                  pd->speed_khz, res->start, id->irq);
 522
 523         return 0;
 524
 525 out4:
 526         free_irq(id->irq, id);
 527 out3:
 528         iounmap(id->iobase);
 529 out2:
 530         release_resource(id->ioarea);
 531         kfree(id->ioarea);
 532 out1:
 533         kfree(id);
 534 out0:
 535         return ret;
 536 }
 537
 538 static void sh7760_i2c_remove(struct platform_device *pdev)
 539 {
 540         struct cami2c *id = platform_get_drvdata(pdev);
 541
 542         i2c_del_adapter(&id->adap);
 543         free_irq(id->irq, id);
 544         iounmap(id->iobase);
 545         release_resource(id->ioarea);
 546         kfree(id->ioarea);
 547         kfree(id);
 548 }
 549
 550 static struct platform_driver sh7760_i2c_drv = {
 551         .driver = {
 552                 .name   = SH7760_I2C_DEVNAME,
 553         },
 554         .probe          = sh7760_i2c_probe,
 555         .remove         = sh7760_i2c_remove,
 556 };
 557
 558 module_platform_driver(sh7760_i2c_drv);
 559
 560 MODULE_LICENSE("GPL");
 561 MODULE_DESCRIPTION("SH7760 I2C bus driver");
 562 MODULE_AUTHOR("Manuel Lauss <mano@roarinelk.homelinux.net>");