LXR linux/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
  81struct 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
 102static inline void OUT32(struct cami2c *cam, int reg, unsigned long val)
 103{
 104        __raw_writel(val, (unsigned long)cam->iobase + reg);
 105}
 106
 107static inline unsigned long IN32(struct cami2c *cam, int reg)
 108{
 109        return __raw_readl((unsigned long)cam->iobase + reg);
 110}
 111
 112static 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        }
 223out:
 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 */
 240static 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 */
 266static 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
 298static inline int sh7760_i2c_busy_check(struct cami2c *id)
 299{
 300        return (IN32(id, I2CMCR) & MCR_FSDA);
 301}
 302
 303static 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;
 318retry:
 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
 376static u32 sh7760_i2c_func(struct i2c_adapter *adap)
 377{
 378        return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
 379}
 380
 381static 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 */
 392static 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
 432static 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(struct cami2c), GFP_KERNEL);
 447        if (!id) {
 448                dev_err(&pdev->dev, "no mem for private data\n");
 449                ret = -ENOMEM;
 450                goto out0;
 451        }
 452
 453        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 454        if (!res) {
 455                dev_err(&pdev->dev, "no mmio resources\n");
 456                ret = -ENODEV;
 457                goto out1;
 458        }
 459
 460        id->ioarea = request_mem_region(res->start, REGSIZE, pdev->name);
 461        if (!id->ioarea) {
 462                dev_err(&pdev->dev, "mmio already reserved\n");
 463                ret = -EBUSY;
 464                goto out1;
 465        }
 466
 467        id->iobase = ioremap(res->start, REGSIZE);
 468        if (!id->iobase) {
 469                dev_err(&pdev->dev, "cannot ioremap\n");
 470                ret = -ENODEV;
 471                goto out2;
 472        }
 473
 474        id->irq = platform_get_irq(pdev, 0);
 475
 476        id->adap.nr = pdev->id;
 477        id->adap.algo = &sh7760_i2c_algo;
 478        id->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 479        id->adap.retries = 3;
 480        id->adap.algo_data = id;
 481        id->adap.dev.parent = &pdev->dev;
 482        snprintf(id->adap.name, sizeof(id->adap.name),
 483                "SH7760 I2C at %08lx", (unsigned long)res->start);
 484
 485        OUT32(id, I2CMCR, 0);
 486        OUT32(id, I2CMSR, 0);
 487        OUT32(id, I2CMIER, 0);
 488        OUT32(id, I2CMAR, 0);
 489        OUT32(id, I2CSIER, 0);
 490        OUT32(id, I2CSAR, 0);
 491        OUT32(id, I2CSCR, 0);
 492        OUT32(id, I2CSSR, 0);
 493        OUT32(id, I2CFIER, 0);
 494        OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
 495        OUT32(id, I2CFSR, 0);
 496
 497        ret = calc_CCR(pd->speed_khz * 1000);
 498        if (ret < 0) {
 499                dev_err(&pdev->dev, "invalid SCL clock: %dkHz\n",
 500                        pd->speed_khz);
 501                goto out3;
 502        }
 503        OUT32(id, I2CCCR, ret);
 504
 505        if (request_irq(id->irq, sh7760_i2c_irq, 0,
 506                        SH7760_I2C_DEVNAME, id)) {
 507                dev_err(&pdev->dev, "cannot get irq %d\n", id->irq);
 508                ret = -EBUSY;
 509                goto out3;
 510        }
 511
 512        ret = i2c_add_numbered_adapter(&id->adap);
 513        if (ret < 0) {
 514                dev_err(&pdev->dev, "reg adap failed: %d\n", ret);
 515                goto out4;
 516        }
 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
 525out4:
 526        free_irq(id->irq, id);
 527out3:
 528        iounmap(id->iobase);
 529out2:
 530        release_resource(id->ioarea);
 531        kfree(id->ioarea);
 532out1:
 533        kfree(id);
 534out0:
 535        return ret;
 536}
 537
 538static int 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        return 0;
 550}
 551
 552static struct platform_driver sh7760_i2c_drv = {
 553        .driver = {
 554                .name   = SH7760_I2C_DEVNAME,
 555        },
 556        .probe          = sh7760_i2c_probe,
 557        .remove         = sh7760_i2c_remove,
 558};
 559
 560module_platform_driver(sh7760_i2c_drv);
 561
 562MODULE_LICENSE("GPL");
 563MODULE_DESCRIPTION("SH7760 I2C bus driver");
 564MODULE_AUTHOR("Manuel Lauss <mano@roarinelk.homelinux.net>");
 565