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/init.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/ioport.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/slab.h>
  19 #include <linux/io.h>
  20 #include <linux/module.h>
  21
  22 #include <asm/clock.h>
  23 #include <asm/i2c-sh7760.h>
  24
  25 /* register offsets */
  26 #define I2CSCR          0x0             /* slave ctrl           */
  27 #define I2CMCR          0x4             /* master ctrl          */
  28 #define I2CSSR          0x8             /* slave status         */
  29 #define I2CMSR          0xC             /* master status        */
  30 #define I2CSIER         0x10            /* slave irq enable     */
  31 #define I2CMIER         0x14            /* master irq enable    */
  32 #define I2CCCR          0x18            /* clock dividers       */
  33 #define I2CSAR          0x1c            /* slave address        */
  34 #define I2CMAR          0x20            /* master address       */
  35 #define I2CRXTX         0x24            /* data port            */
  36 #define I2CFCR          0x28            /* fifo control         */
  37 #define I2CFSR          0x2C            /* fifo status          */
  38 #define I2CFIER         0x30            /* fifo irq enable      */
  39 #define I2CRFDR         0x34            /* rx fifo count        */
  40 #define I2CTFDR         0x38            /* tx fifo count        */
  41
  42 #define REGSIZE         0x3C
  43
  44 #define MCR_MDBS        0x80            /* non-fifo mode switch */
  45 #define MCR_FSCL        0x40            /* override SCL pin     */
  46 #define MCR_FSDA        0x20            /* override SDA pin     */
  47 #define MCR_OBPC        0x10            /* override pins        */
  48 #define MCR_MIE         0x08            /* master if enable     */
  49 #define MCR_TSBE        0x04
  50 #define MCR_FSB         0x02            /* force stop bit       */
  51 #define MCR_ESG         0x01            /* en startbit gen.     */
  52
  53 #define MSR_MNR         0x40            /* nack received        */
  54 #define MSR_MAL         0x20            /* arbitration lost     */
  55 #define MSR_MST         0x10            /* sent a stop          */
  56 #define MSR_MDE         0x08
  57 #define MSR_MDT         0x04
  58 #define MSR_MDR         0x02
  59 #define MSR_MAT         0x01            /* slave addr xfer done */
  60
  61 #define MIE_MNRE        0x40            /* nack irq en          */
  62 #define MIE_MALE        0x20            /* arblos irq en        */
  63 #define MIE_MSTE        0x10            /* stop irq en          */
  64 #define MIE_MDEE        0x08
  65 #define MIE_MDTE        0x04
  66 #define MIE_MDRE        0x02
  67 #define MIE_MATE        0x01            /* address sent irq en  */
  68
  69 #define FCR_RFRST       0x02            /* reset rx fifo        */
  70 #define FCR_TFRST       0x01            /* reset tx fifo        */
  71
  72 #define FSR_TEND        0x04            /* last byte sent       */
  73 #define FSR_RDF         0x02            /* rx fifo trigger      */
  74 #define FSR_TDFE        0x01            /* tx fifo empty        */
  75
  76 #define FIER_TEIE       0x04            /* tx fifo empty irq en */
  77 #define FIER_RXIE       0x02            /* rx fifo trig irq en  */
  78 #define FIER_TXIE       0x01            /* tx fifo trig irq en  */
  79
  80 #define FIFO_SIZE       16
  81
  82 struct cami2c {
  83         void __iomem *iobase;
  84         struct i2c_adapter adap;
  85
  86         /* message processing */
  87         struct i2c_msg  *msg;
  88 #define IDF_SEND        1
  89 #define IDF_RECV        2
  90 #define IDF_STOP        4
  91         int             flags;
  92
  93 #define IDS_DONE        1
  94 #define IDS_ARBLOST     2
  95 #define IDS_NACK        4
  96         int             status;
  97         struct completion xfer_done;
  98
  99         int irq;
 100         struct resource *ioarea;
 101 };
 102
 103 static inline void OUT32(struct cami2c *cam, int reg, unsigned long val)
 104 {
 105         __raw_writel(val, (unsigned long)cam->iobase + reg);
 106 }
 107
 108 static inline unsigned long IN32(struct cami2c *cam, int reg)
 109 {
 110         return __raw_readl((unsigned long)cam->iobase + reg);
 111 }
 112
 113 static irqreturn_t sh7760_i2c_irq(int irq, void *ptr)
 114 {
 115         struct cami2c *id = ptr;
 116         struct i2c_msg *msg = id->msg;
 117         char *data = msg->buf;
 118         unsigned long msr, fsr, fier, len;
 119
 120         msr = IN32(id, I2CMSR);
 121         fsr = IN32(id, I2CFSR);
 122
 123         /* arbitration lost */
 124         if (msr & MSR_MAL) {
 125                 OUT32(id, I2CMCR, 0);
 126                 OUT32(id, I2CSCR, 0);
 127                 OUT32(id, I2CSAR, 0);
 128                 id->status |= IDS_DONE | IDS_ARBLOST;
 129                 goto out;
 130         }
 131
 132         if (msr & MSR_MNR) {
 133                 /* NACK handling is very screwed up.  After receiving a
 134                  * NAK IRQ one has to wait a bit  before writing to any
 135                  * registers, or the ctl will lock up. After that delay
 136                  * do a normal i2c stop. Then wait at least 1 ms before
 137                  * attempting another transfer or ctl will stop working
 138                  */
 139                 udelay(100);    /* wait or risk ctl hang */
 140                 OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
 141                 OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
 142                 OUT32(id, I2CFIER, 0);
 143                 OUT32(id, I2CMIER, MIE_MSTE);
 144                 OUT32(id, I2CSCR, 0);
 145                 OUT32(id, I2CSAR, 0);
 146                 id->status |= IDS_NACK;
 147                 msr &= ~MSR_MAT;
 148                 fsr = 0;
 149                 /* In some cases the MST bit is also set. */
 150         }
 151
 152         /* i2c-stop was sent */
 153         if (msr & MSR_MST) {
 154                 id->status |= IDS_DONE;
 155                 goto out;
 156         }
 157
 158         /* i2c slave addr was sent; set to "normal" operation */
 159         if (msr & MSR_MAT)
 160                 OUT32(id, I2CMCR, MCR_MIE);
 161
 162         fier = IN32(id, I2CFIER);
 163
 164         if (fsr & FSR_RDF) {
 165                 len = IN32(id, I2CRFDR);
 166                 if (msg->len <= len) {
 167                         if (id->flags & IDF_STOP) {
 168                                 OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
 169                                 OUT32(id, I2CFIER, 0);
 170                                 /* manual says: wait >= 0.5 SCL times */
 171                                 udelay(5);
 172                                 /* next int should be MST */
 173                         } else {
 174                                 id->status |= IDS_DONE;
 175                                 /* keep the RDF bit: ctrl holds SCL low
 176                                  * until the setup for the next i2c_msg
 177                                  * clears this bit.
 178                                  */
 179                                 fsr &= ~FSR_RDF;
 180                         }
 181                 }
 182                 while (msg->len && len) {
 183                         *data++ = IN32(id, I2CRXTX);
 184                         msg->len--;
 185                         len--;
 186                 }
 187
 188                 if (msg->len) {
 189                         len = (msg->len >= FIFO_SIZE) ? FIFO_SIZE - 1
 190                                                       : msg->len - 1;
 191
 192                         OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xf) << 4));
 193                 }
 194
 195         } else if (id->flags & IDF_SEND) {
 196                 if ((fsr & FSR_TEND) && (msg->len < 1)) {
 197                         if (id->flags & IDF_STOP) {
 198                                 OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
 199                         } else {
 200                                 id->status |= IDS_DONE;
 201                                 /* keep the TEND bit: ctl holds SCL low
 202                                  * until the setup for the next i2c_msg
 203                                  * clears this bit.
 204                                  */
 205                                 fsr &= ~FSR_TEND;
 206                         }
 207                 }
 208                 if (fsr & FSR_TDFE) {
 209                         while (msg->len && (IN32(id, I2CTFDR) < FIFO_SIZE)) {
 210                                 OUT32(id, I2CRXTX, *data++);
 211                                 msg->len--;
 212                         }
 213
 214                         if (msg->len < 1) {
 215                                 fier &= ~FIER_TXIE;
 216                                 OUT32(id, I2CFIER, fier);
 217                         } else {
 218                                 len = (msg->len >= FIFO_SIZE) ? 2 : 0;
 219                                 OUT32(id, I2CFCR,
 220                                           FCR_RFRST | ((len & 3) << 2));
 221                         }
 222                 }
 223         }
 224 out:
 225         if (id->status & IDS_DONE) {
 226                 OUT32(id, I2CMIER, 0);
 227                 OUT32(id, I2CFIER, 0);
 228                 id->msg = NULL;
 229                 complete(&id->xfer_done);
 230         }
 231         /* clear status flags and ctrl resumes work */
 232         OUT32(id, I2CMSR, ~msr);
 233         OUT32(id, I2CFSR, ~fsr);
 234         OUT32(id, I2CSSR, 0);
 235
 236         return IRQ_HANDLED;
 237 }
 238
 239
 240 /* prepare and start a master receive operation */
 241 static void sh7760_i2c_mrecv(struct cami2c *id)
 242 {
 243         int len;
 244
 245         id->flags |= IDF_RECV;
 246
 247         /* set the slave addr reg; otherwise rcv wont work! */
 248         OUT32(id, I2CSAR, 0xfe);
 249         OUT32(id, I2CMAR, (id->msg->addr << 1) | 1);
 250
 251         /* adjust rx fifo trigger */
 252         if (id->msg->len >= FIFO_SIZE)
 253                 len = FIFO_SIZE - 1;    /* trigger at fifo full */
 254         else
 255                 len = id->msg->len - 1; /* trigger before all received */
 256
 257         OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
 258         OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xF) << 4));
 259
 260         OUT32(id, I2CMSR, 0);
 261         OUT32(id, I2CMCR, MCR_MIE | MCR_ESG);
 262         OUT32(id, I2CMIER, MIE_MNRE | MIE_MALE | MIE_MSTE | MIE_MATE);
 263         OUT32(id, I2CFIER, FIER_RXIE);
 264 }
 265
 266 /* prepare and start a master send operation */
 267 static void sh7760_i2c_msend(struct cami2c *id)
 268 {
 269         int len;
 270
 271         id->flags |= IDF_SEND;
 272
 273         /* set the slave addr reg; otherwise xmit wont work! */
 274         OUT32(id, I2CSAR, 0xfe);
 275         OUT32(id, I2CMAR, (id->msg->addr << 1) | 0);
 276
 277         /* adjust tx fifo trigger */
 278         if (id->msg->len >= FIFO_SIZE)
 279                 len = 2;        /* trig: 2 bytes left in TX fifo */
 280         else
 281                 len = 0;        /* trig: 8 bytes left in TX fifo */
 282
 283         OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
 284         OUT32(id, I2CFCR, FCR_RFRST | ((len & 3) << 2));
 285
 286         while (id->msg->len && IN32(id, I2CTFDR) < FIFO_SIZE) {
 287                 OUT32(id, I2CRXTX, *(id->msg->buf));
 288                 (id->msg->len)--;
 289                 (id->msg->buf)++;
 290         }
 291
 292         OUT32(id, I2CMSR, 0);
 293         OUT32(id, I2CMCR, MCR_MIE | MCR_ESG);
 294         OUT32(id, I2CFSR, 0);
 295         OUT32(id, I2CMIER, MIE_MNRE | MIE_MALE | MIE_MSTE | MIE_MATE);
 296         OUT32(id, I2CFIER, FIER_TEIE | (id->msg->len ? FIER_TXIE : 0));
 297 }
 298
 299 static inline int sh7760_i2c_busy_check(struct cami2c *id)
 300 {
 301         return (IN32(id, I2CMCR) & MCR_FSDA);
 302 }
 303
 304 static int sh7760_i2c_master_xfer(struct i2c_adapter *adap,
 305                                   struct i2c_msg *msgs,
 306                                   int num)
 307 {
 308         struct cami2c *id = adap->algo_data;
 309         int i, retr;
 310
 311         if (sh7760_i2c_busy_check(id)) {
 312                 dev_err(&adap->dev, "sh7760-i2c%d: bus busy!\n", adap->nr);
 313                 return -EBUSY;
 314         }
 315
 316         i = 0;
 317         while (i < num) {
 318                 retr = adap->retries;
 319 retry:
 320                 id->flags = ((i == (num-1)) ? IDF_STOP : 0);
 321                 id->status = 0;
 322                 id->msg = msgs;
 323                 init_completion(&id->xfer_done);
 324
 325                 if (msgs->flags & I2C_M_RD)
 326                         sh7760_i2c_mrecv(id);
 327                 else
 328                         sh7760_i2c_msend(id);
 329
 330                 wait_for_completion(&id->xfer_done);
 331
 332                 if (id->status == 0) {
 333                         num = -EIO;
 334                         break;
 335                 }
 336
 337                 if (id->status & IDS_NACK) {
 338                         /* wait a bit or i2c module stops working */
 339                         mdelay(1);
 340                         num = -EREMOTEIO;
 341                         break;
 342                 }
 343
 344                 if (id->status & IDS_ARBLOST) {
 345                         if (retr--) {
 346                                 mdelay(2);
 347                                 goto retry;
 348                         }
 349                         num = -EREMOTEIO;
 350                         break;
 351                 }
 352
 353                 msgs++;
 354                 i++;
 355         }
 356
 357         id->msg = NULL;
 358         id->flags = 0;
 359         id->status = 0;
 360
 361         OUT32(id, I2CMCR, 0);
 362         OUT32(id, I2CMSR, 0);
 363         OUT32(id, I2CMIER, 0);
 364         OUT32(id, I2CFIER, 0);
 365
 366         /* reset slave module registers too: master mode enables slave
 367          * module for receive ops (ack, data). Without this reset,
 368          * eternal bus activity might be reported after NACK / ARBLOST.
 369          */
 370         OUT32(id, I2CSCR, 0);
 371         OUT32(id, I2CSAR, 0);
 372         OUT32(id, I2CSSR, 0);
 373
 374         return num;
 375 }
 376
 377 static u32 sh7760_i2c_func(struct i2c_adapter *adap)
 378 {
 379         return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
 380 }
 381
 382 static const struct i2c_algorithm sh7760_i2c_algo = {
 383         .master_xfer    = sh7760_i2c_master_xfer,
 384         .functionality  = sh7760_i2c_func,
 385 };
 386
 387 /* calculate CCR register setting for a desired scl clock.  SCL clock is
 388  * derived from I2C module clock  (iclk)  which in turn is derived from
 389  * peripheral module clock (mclk, usually around 33MHz):
 390  * iclk = mclk/(CDF + 1).  iclk must be < 20MHz.
 391  * scl = iclk/(SCGD*8 + 20).
 392  */
 393 static int calc_CCR(unsigned long scl_hz)
 394 {
 395         struct clk *mclk;
 396         unsigned long mck, m1, dff, odff, iclk;
 397         signed char cdf, cdfm;
 398         int scgd, scgdm, scgds;
 399
 400         mclk = clk_get(NULL, "peripheral_clk");
 401         if (IS_ERR(mclk)) {
 402                 return PTR_ERR(mclk);
 403         } else {
 404                 mck = mclk->rate;
 405                 clk_put(mclk);
 406         }
 407
 408         odff = scl_hz;
 409         scgdm = cdfm = m1 = 0;
 410         for (cdf = 3; cdf >= 0; cdf--) {
 411                 iclk = mck / (1 + cdf);
 412                 if (iclk >= 20000000)
 413                         continue;
 414                 scgds = ((iclk / scl_hz) - 20) >> 3;
 415                 for (scgd = scgds; (scgd < 63) && scgd <= scgds + 1; scgd++) {
 416                         m1 = iclk / (20 + (scgd << 3));
 417                         dff = abs(scl_hz - m1);
 418                         if (dff < odff) {
 419                                 odff = dff;
 420                                 cdfm = cdf;
 421                                 scgdm = scgd;
 422                         }
 423                 }
 424         }
 425         /* fail if more than 25% off of requested SCL */
 426         if (odff > (scl_hz >> 2))
 427                 return -EINVAL;
 428
 429         /* create a CCR register value */
 430         return ((scgdm << 2) | cdfm);
 431 }
 432
 433 static int sh7760_i2c_probe(struct platform_device *pdev)
 434 {
 435         struct sh7760_i2c_platdata *pd;
 436         struct resource *res;
 437         struct cami2c *id;
 438         int ret;
 439
 440         pd = pdev->dev.platform_data;
 441         if (!pd) {
 442                 dev_err(&pdev->dev, "no platform_data!\n");
 443                 ret = -ENODEV;
 444                 goto out0;
 445         }
 446
 447         id = kzalloc(sizeof(struct cami2c), GFP_KERNEL);
 448         if (!id) {
 449                 dev_err(&pdev->dev, "no mem for private data\n");
 450                 ret = -ENOMEM;
 451                 goto out0;
 452         }
 453
 454         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 455         if (!res) {
 456                 dev_err(&pdev->dev, "no mmio resources\n");
 457                 ret = -ENODEV;
 458                 goto out1;
 459         }
 460
 461         id->ioarea = request_mem_region(res->start, REGSIZE, pdev->name);
 462         if (!id->ioarea) {
 463                 dev_err(&pdev->dev, "mmio already reserved\n");
 464                 ret = -EBUSY;
 465                 goto out1;
 466         }
 467
 468         id->iobase = ioremap(res->start, REGSIZE);
 469         if (!id->iobase) {
 470                 dev_err(&pdev->dev, "cannot ioremap\n");
 471                 ret = -ENODEV;
 472                 goto out2;
 473         }
 474
 475         id->irq = platform_get_irq(pdev, 0);
 476
 477         id->adap.nr = pdev->id;
 478         id->adap.algo = &sh7760_i2c_algo;
 479         id->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 480         id->adap.retries = 3;
 481         id->adap.algo_data = id;
 482         id->adap.dev.parent = &pdev->dev;
 483         snprintf(id->adap.name, sizeof(id->adap.name),
 484                 "SH7760 I2C at %08lx", (unsigned long)res->start);
 485
 486         OUT32(id, I2CMCR, 0);
 487         OUT32(id, I2CMSR, 0);
 488         OUT32(id, I2CMIER, 0);
 489         OUT32(id, I2CMAR, 0);
 490         OUT32(id, I2CSIER, 0);
 491         OUT32(id, I2CSAR, 0);
 492         OUT32(id, I2CSCR, 0);
 493         OUT32(id, I2CSSR, 0);
 494         OUT32(id, I2CFIER, 0);
 495         OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
 496         OUT32(id, I2CFSR, 0);
 497
 498         ret = calc_CCR(pd->speed_khz * 1000);
 499         if (ret < 0) {
 500                 dev_err(&pdev->dev, "invalid SCL clock: %dkHz\n",
 501                         pd->speed_khz);
 502                 goto out3;
 503         }
 504         OUT32(id, I2CCCR, ret);
 505
 506         if (request_irq(id->irq, sh7760_i2c_irq, 0,
 507                         SH7760_I2C_DEVNAME, id)) {
 508                 dev_err(&pdev->dev, "cannot get irq %d\n", id->irq);
 509                 ret = -EBUSY;
 510                 goto out3;
 511         }
 512
 513         ret = i2c_add_numbered_adapter(&id->adap);
 514         if (ret < 0) {
 515                 dev_err(&pdev->dev, "reg adap failed: %d\n", ret);
 516                 goto out4;
 517         }
 518
 519         platform_set_drvdata(pdev, id);
 520
 521         dev_info(&pdev->dev, "%d kHz mmio %08x irq %d\n",
 522                  pd->speed_khz, res->start, id->irq);
 523
 524         return 0;
 525
 526 out4:
 527         free_irq(id->irq, id);
 528 out3:
 529         iounmap(id->iobase);
 530 out2:
 531         release_resource(id->ioarea);
 532         kfree(id->ioarea);
 533 out1:
 534         kfree(id);
 535 out0:
 536         return ret;
 537 }
 538
 539 static int sh7760_i2c_remove(struct platform_device *pdev)
 540 {
 541         struct cami2c *id = platform_get_drvdata(pdev);
 542
 543         i2c_del_adapter(&id->adap);
 544         free_irq(id->irq, id);
 545         iounmap(id->iobase);
 546         release_resource(id->ioarea);
 547         kfree(id->ioarea);
 548         kfree(id);
 549
 550         return 0;
 551 }
 552
 553 static struct platform_driver sh7760_i2c_drv = {
 554         .driver = {
 555                 .name   = SH7760_I2C_DEVNAME,
 556                 .owner  = THIS_MODULE,
 557         },
 558         .probe          = sh7760_i2c_probe,
 559         .remove         = sh7760_i2c_remove,
 560 };
 561
 562 module_platform_driver(sh7760_i2c_drv);
 563
 564 MODULE_LICENSE("GPL");
 565 MODULE_DESCRIPTION("SH7760 I2C bus driver");
 566 MODULE_AUTHOR("Manuel Lauss <mano@roarinelk.homelinux.net>");