drivers/i2c/busses/i2c-iop3xx.c

   1 /* ------------------------------------------------------------------------- */
   2 /* i2c-iop3xx.c i2c driver algorithms for Intel XScale IOP3xx & IXP46x       */
   3 /* ------------------------------------------------------------------------- */
   4 /* Copyright (C) 2003 Peter Milne, D-TACQ Solutions Ltd
   5  *                    <Peter dot Milne at D hyphen TACQ dot com>
   6  *
   7  * With acknowledgements to i2c-algo-ibm_ocp.c by
   8  * Ian DaSilva, MontaVista Software, Inc. idasilva@mvista.com
   9  *
  10  * And i2c-algo-pcf.c, which was created by Simon G. Vogl and Hans Berglund:
  11  *
  12  * Copyright (C) 1995-1997 Simon G. Vogl, 1998-2000 Hans Berglund
  13  *
  14  * And which acknowledged Kyösti Mälkki <kmalkki@cc.hut.fi>,
  15  * Frodo Looijaard <frodol@dds.nl>, Martin Bailey<mbailey@littlefeet-inc.com>
  16  *
  17  * Major cleanup by Deepak Saxena <dsaxena@plexity.net>, 01/2005:
  18  *
  19  * - Use driver model to pass per-chip info instead of hardcoding and #ifdefs
  20  * - Use ioremap/__raw_readl/__raw_writel instead of direct dereference
  21  * - Make it work with IXP46x chips
  22  * - Cleanup function names, coding style, etc
  23  *
  24  * - writing to slave address causes latchup on iop331.
  25  *      fix: driver refuses to address self.
  26  *
  27  * This program is free software; you can redistribute it and/or modify
  28  * it under the terms of the GNU General Public License as published by
  29  * the Free Software Foundation, version 2.
  30  */
  31
  32 #include <linux/interrupt.h>
  33 #include <linux/kernel.h>
  34 #include <linux/module.h>
  35 #include <linux/delay.h>
  36 #include <linux/slab.h>
  37 #include <linux/init.h>
  38 #include <linux/errno.h>
  39 #include <linux/sched.h>
  40 #include <linux/platform_device.h>
  41 #include <linux/i2c.h>
  42
  43 #include <asm/io.h>
  44
  45 #include "i2c-iop3xx.h"
  46
  47 /* global unit counter */
  48 static int i2c_id;
  49
  50 static inline unsigned char
  51 iic_cook_addr(struct i2c_msg *msg)
  52 {
  53         unsigned char addr;
  54
  55         addr = (msg->addr << 1);
  56
  57         if (msg->flags & I2C_M_RD)
  58                 addr |= 1;
  59
  60         /*
  61          * Read or Write?
  62          */
  63         if (msg->flags & I2C_M_REV_DIR_ADDR)
  64                 addr ^= 1;
  65
  66         return addr;
  67 }
  68
  69 static void
  70 iop3xx_i2c_reset(struct i2c_algo_iop3xx_data *iop3xx_adap)
  71 {
  72         /* Follows devman 9.3 */
  73         __raw_writel(IOP3XX_ICR_UNIT_RESET, iop3xx_adap->ioaddr + CR_OFFSET);
  74         __raw_writel(IOP3XX_ISR_CLEARBITS, iop3xx_adap->ioaddr + SR_OFFSET);
  75         __raw_writel(0, iop3xx_adap->ioaddr + CR_OFFSET);
  76 }
  77
  78 static void
  79 iop3xx_i2c_enable(struct i2c_algo_iop3xx_data *iop3xx_adap)
  80 {
  81         u32 cr = IOP3XX_ICR_GCD | IOP3XX_ICR_SCLEN | IOP3XX_ICR_UE;
  82
  83         /*
  84          * Every time unit enable is asserted, GPOD needs to be cleared
  85          * on IOP321 to avoid data corruption on the bus.
  86          */
  87 #ifdef CONFIG_ARCH_IOP321
  88 #define IOP321_GPOD_I2C0    0x00c0  /* clear these bits to enable ch0 */
  89 #define IOP321_GPOD_I2C1    0x0030  /* clear these bits to enable ch1 */
  90
  91         *IOP321_GPOD &= (iop3xx_adap->id == 0) ? ~IOP321_GPOD_I2C0 :
  92                 ~IOP321_GPOD_I2C1;
  93 #endif
  94         /* NB SR bits not same position as CR IE bits :-( */
  95         iop3xx_adap->SR_enabled =
  96                 IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD |
  97                 IOP3XX_ISR_RXFULL | IOP3XX_ISR_TXEMPTY;
  98
  99         cr |= IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
 100                 IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE;
 101
 102         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 103 }
 104
 105 static void
 106 iop3xx_i2c_transaction_cleanup(struct i2c_algo_iop3xx_data *iop3xx_adap)
 107 {
 108         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 109
 110         cr &= ~(IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE |
 111                 IOP3XX_ICR_MSTOP | IOP3XX_ICR_SCLEN);
 112
 113         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 114 }
 115
 116 /*
 117  * NB: the handler has to clear the source of the interrupt!
 118  * Then it passes the SR flags of interest to BH via adap data
 119  */
 120 static irqreturn_t
 121 iop3xx_i2c_irq_handler(int this_irq, void *dev_id, struct pt_regs *regs)
 122 {
 123         struct i2c_algo_iop3xx_data *iop3xx_adap = dev_id;
 124         u32 sr = __raw_readl(iop3xx_adap->ioaddr + SR_OFFSET);
 125
 126         if ((sr &= iop3xx_adap->SR_enabled)) {
 127                 __raw_writel(sr, iop3xx_adap->ioaddr + SR_OFFSET);
 128                 iop3xx_adap->SR_received |= sr;
 129                 wake_up_interruptible(&iop3xx_adap->waitq);
 130         }
 131         return IRQ_HANDLED;
 132 }
 133
 134 /* check all error conditions, clear them , report most important */
 135 static int
 136 iop3xx_i2c_error(u32 sr)
 137 {
 138         int rc = 0;
 139
 140         if ((sr & IOP3XX_ISR_BERRD)) {
 141                 if ( !rc ) rc = -I2C_ERR_BERR;
 142         }
 143         if ((sr & IOP3XX_ISR_ALD)) {
 144                 if ( !rc ) rc = -I2C_ERR_ALD;
 145         }
 146         return rc;
 147 }
 148
 149 static inline u32
 150 iop3xx_i2c_get_srstat(struct i2c_algo_iop3xx_data *iop3xx_adap)
 151 {
 152         unsigned long flags;
 153         u32 sr;
 154
 155         spin_lock_irqsave(&iop3xx_adap->lock, flags);
 156         sr = iop3xx_adap->SR_received;
 157         iop3xx_adap->SR_received = 0;
 158         spin_unlock_irqrestore(&iop3xx_adap->lock, flags);
 159
 160         return sr;
 161 }
 162
 163 /*
 164  * sleep until interrupted, then recover and analyse the SR
 165  * saved by handler
 166  */
 167 typedef int (* compare_func)(unsigned test, unsigned mask);
 168 /* returns 1 on correct comparison */
 169
 170 static int
 171 iop3xx_i2c_wait_event(struct i2c_algo_iop3xx_data *iop3xx_adap,
 172                           unsigned flags, unsigned* status,
 173                           compare_func compare)
 174 {
 175         unsigned sr = 0;
 176         int interrupted;
 177         int done;
 178         int rc = 0;
 179
 180         do {
 181                 interrupted = wait_event_interruptible_timeout (
 182                         iop3xx_adap->waitq,
 183                         (done = compare( sr = iop3xx_i2c_get_srstat(iop3xx_adap) ,flags )),
 184                         1 * HZ;
 185                         );
 186                 if ((rc = iop3xx_i2c_error(sr)) < 0) {
 187                         *status = sr;
 188                         return rc;
 189                 } else if (!interrupted) {
 190                         *status = sr;
 191                         return -ETIMEDOUT;
 192                 }
 193         } while(!done);
 194
 195         *status = sr;
 196
 197         return 0;
 198 }
 199
 200 /*
 201  * Concrete compare_funcs
 202  */
 203 static int
 204 all_bits_clear(unsigned test, unsigned mask)
 205 {
 206         return (test & mask) == 0;
 207 }
 208
 209 static int
 210 any_bits_set(unsigned test, unsigned mask)
 211 {
 212         return (test & mask) != 0;
 213 }
 214
 215 static int
 216 iop3xx_i2c_wait_tx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 217 {
 218         return iop3xx_i2c_wait_event(
 219                 iop3xx_adap,
 220                 IOP3XX_ISR_TXEMPTY | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
 221                 status, any_bits_set);
 222 }
 223
 224 static int
 225 iop3xx_i2c_wait_rx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 226 {
 227         return iop3xx_i2c_wait_event(
 228                 iop3xx_adap,
 229                 IOP3XX_ISR_RXFULL | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
 230                 status, any_bits_set);
 231 }
 232
 233 static int
 234 iop3xx_i2c_wait_idle(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 235 {
 236         return iop3xx_i2c_wait_event(
 237                 iop3xx_adap, IOP3XX_ISR_UNITBUSY, status, all_bits_clear);
 238 }
 239
 240 static int
 241 iop3xx_i2c_send_target_addr(struct i2c_algo_iop3xx_data *iop3xx_adap,
 242                                 struct i2c_msg* msg)
 243 {
 244         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 245         int status;
 246         int rc;
 247
 248         /* avoid writing to my slave address (hangs on 80331),
 249          * forbidden in Intel developer manual
 250          */
 251         if (msg->addr == MYSAR) {
 252                 return -EBUSY;
 253         }
 254
 255         __raw_writel(iic_cook_addr(msg), iop3xx_adap->ioaddr + DBR_OFFSET);
 256
 257         cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
 258         cr |= IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE;
 259
 260         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 261         rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
 262
 263         return rc;
 264 }
 265
 266 static int
 267 iop3xx_i2c_write_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char byte,
 268                                 int stop)
 269 {
 270         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 271         int status;
 272         int rc = 0;
 273
 274         __raw_writel(byte, iop3xx_adap->ioaddr + DBR_OFFSET);
 275         cr &= ~IOP3XX_ICR_MSTART;
 276         if (stop) {
 277                 cr |= IOP3XX_ICR_MSTOP;
 278         } else {
 279                 cr &= ~IOP3XX_ICR_MSTOP;
 280         }
 281         cr |= IOP3XX_ICR_TBYTE;
 282         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 283         rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
 284
 285         return rc;
 286 }
 287
 288 static int
 289 iop3xx_i2c_read_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char* byte,
 290                                 int stop)
 291 {
 292         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 293         int status;
 294         int rc = 0;
 295
 296         cr &= ~IOP3XX_ICR_MSTART;
 297
 298         if (stop) {
 299                 cr |= IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK;
 300         } else {
 301                 cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
 302         }
 303         cr |= IOP3XX_ICR_TBYTE;
 304         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 305
 306         rc = iop3xx_i2c_wait_rx_done(iop3xx_adap, &status);
 307
 308         *byte = __raw_readl(iop3xx_adap->ioaddr + DBR_OFFSET);
 309
 310         return rc;
 311 }
 312
 313 static int
 314 iop3xx_i2c_writebytes(struct i2c_adapter *i2c_adap, const char *buf, int count)
 315 {
 316         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 317         int ii;
 318         int rc = 0;
 319
 320         for (ii = 0; rc == 0 && ii != count; ++ii)
 321                 rc = iop3xx_i2c_write_byte(iop3xx_adap, buf[ii], ii==count-1);
 322         return rc;
 323 }
 324
 325 static int
 326 iop3xx_i2c_readbytes(struct i2c_adapter *i2c_adap, char *buf, int count)
 327 {
 328         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 329         int ii;
 330         int rc = 0;
 331
 332         for (ii = 0; rc == 0 && ii != count; ++ii)
 333                 rc = iop3xx_i2c_read_byte(iop3xx_adap, &buf[ii], ii==count-1);
 334
 335         return rc;
 336 }
 337
 338 /*
 339  * Description:  This function implements combined transactions.  Combined
 340  * transactions consist of combinations of reading and writing blocks of data.
 341  * FROM THE SAME ADDRESS
 342  * Each transfer (i.e. a read or a write) is separated by a repeated start
 343  * condition.
 344  */
 345 static int
 346 iop3xx_i2c_handle_msg(struct i2c_adapter *i2c_adap, struct i2c_msg* pmsg)
 347 {
 348         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 349         int rc;
 350
 351         rc = iop3xx_i2c_send_target_addr(iop3xx_adap, pmsg);
 352         if (rc < 0) {
 353                 return rc;
 354         }
 355
 356         if ((pmsg->flags&I2C_M_RD)) {
 357                 return iop3xx_i2c_readbytes(i2c_adap, pmsg->buf, pmsg->len);
 358         } else {
 359                 return iop3xx_i2c_writebytes(i2c_adap, pmsg->buf, pmsg->len);
 360         }
 361 }
 362
 363 /*
 364  * master_xfer() - main read/write entry
 365  */
 366 static int
 367 iop3xx_i2c_master_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
 368                                 int num)
 369 {
 370         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 371         int im = 0;
 372         int ret = 0;
 373         int status;
 374
 375         iop3xx_i2c_wait_idle(iop3xx_adap, &status);
 376         iop3xx_i2c_reset(iop3xx_adap);
 377         iop3xx_i2c_enable(iop3xx_adap);
 378
 379         for (im = 0; ret == 0 && im != num; im++) {
 380                 ret = iop3xx_i2c_handle_msg(i2c_adap, &msgs[im]);
 381         }
 382
 383         iop3xx_i2c_transaction_cleanup(iop3xx_adap);
 384
 385         if(ret)
 386                 return ret;
 387
 388         return im;
 389 }
 390
 391 static int
 392 iop3xx_i2c_algo_control(struct i2c_adapter *adapter, unsigned int cmd,
 393                         unsigned long arg)
 394 {
 395         return 0;
 396 }
 397
 398 static u32
 399 iop3xx_i2c_func(struct i2c_adapter *adap)
 400 {
 401         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 402 }
 403
 404 static const struct i2c_algorithm iop3xx_i2c_algo = {
 405         .master_xfer    = iop3xx_i2c_master_xfer,
 406         .algo_control   = iop3xx_i2c_algo_control,
 407         .functionality  = iop3xx_i2c_func,
 408 };
 409
 410 static int
 411 iop3xx_i2c_remove(struct platform_device *pdev)
 412 {
 413         struct i2c_adapter *padapter = platform_get_drvdata(pdev);
 414         struct i2c_algo_iop3xx_data *adapter_data =
 415                 (struct i2c_algo_iop3xx_data *)padapter->algo_data;
 416         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 417         unsigned long cr = __raw_readl(adapter_data->ioaddr + CR_OFFSET);
 418
 419         /*
 420          * Disable the actual HW unit
 421          */
 422         cr &= ~(IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
 423                 IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE);
 424         __raw_writel(cr, adapter_data->ioaddr + CR_OFFSET);
 425
 426         iounmap((void __iomem*)adapter_data->ioaddr);
 427         release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
 428         kfree(adapter_data);
 429         kfree(padapter);
 430
 431         platform_set_drvdata(pdev, NULL);
 432
 433         return 0;
 434 }
 435
 436 static int
 437 iop3xx_i2c_probe(struct platform_device *pdev)
 438 {
 439         struct resource *res;
 440         int ret, irq;
 441         struct i2c_adapter *new_adapter;
 442         struct i2c_algo_iop3xx_data *adapter_data;
 443
 444         new_adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
 445         if (!new_adapter) {
 446                 ret = -ENOMEM;
 447                 goto out;
 448         }
 449
 450         adapter_data = kzalloc(sizeof(struct i2c_algo_iop3xx_data), GFP_KERNEL);
 451         if (!adapter_data) {
 452                 ret = -ENOMEM;
 453                 goto free_adapter;
 454         }
 455
 456         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 457         if (!res) {
 458                 ret = -ENODEV;
 459                 goto free_both;
 460         }
 461
 462         if (!request_mem_region(res->start, IOP3XX_I2C_IO_SIZE, pdev->name)) {
 463                 ret = -EBUSY;
 464                 goto free_both;
 465         }
 466
 467         /* set the adapter enumeration # */
 468         adapter_data->id = i2c_id++;
 469
 470         adapter_data->ioaddr = (u32)ioremap(res->start, IOP3XX_I2C_IO_SIZE);
 471         if (!adapter_data->ioaddr) {
 472                 ret = -ENOMEM;
 473                 goto release_region;
 474         }
 475
 476         irq = platform_get_irq(pdev, 0);
 477         if (irq < 0) {
 478                 ret = -ENXIO;
 479                 goto unmap;
 480         }
 481         ret = request_irq(irq, iop3xx_i2c_irq_handler, 0,
 482                                 pdev->name, adapter_data);
 483
 484         if (ret) {
 485                 ret = -EIO;
 486                 goto unmap;
 487         }
 488
 489         memcpy(new_adapter->name, pdev->name, strlen(pdev->name));
 490         new_adapter->id = I2C_HW_IOP3XX;
 491         new_adapter->owner = THIS_MODULE;
 492         new_adapter->dev.parent = &pdev->dev;
 493
 494         /*
 495          * Default values...should these come in from board code?
 496          */
 497         new_adapter->timeout = 100;
 498         new_adapter->retries = 3;
 499         new_adapter->algo = &iop3xx_i2c_algo;
 500
 501         init_waitqueue_head(&adapter_data->waitq);
 502         spin_lock_init(&adapter_data->lock);
 503
 504         iop3xx_i2c_reset(adapter_data);
 505         iop3xx_i2c_enable(adapter_data);
 506
 507         platform_set_drvdata(pdev, new_adapter);
 508         new_adapter->algo_data = adapter_data;
 509
 510         i2c_add_adapter(new_adapter);
 511
 512         return 0;
 513
 514 unmap:
 515         iounmap((void __iomem*)adapter_data->ioaddr);
 516
 517 release_region:
 518         release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
 519
 520 free_both:
 521         kfree(adapter_data);
 522
 523 free_adapter:
 524         kfree(new_adapter);
 525
 526 out:
 527         return ret;
 528 }
 529
 530
 531 static struct platform_driver iop3xx_i2c_driver = {
 532         .probe          = iop3xx_i2c_probe,
 533         .remove         = iop3xx_i2c_remove,
 534         .driver         = {
 535                 .owner  = THIS_MODULE,
 536                 .name   = "IOP3xx-I2C",
 537         },
 538 };
 539
 540 static int __init
 541 i2c_iop3xx_init (void)
 542 {
 543         return platform_driver_register(&iop3xx_i2c_driver);
 544 }
 545
 546 static void __exit
 547 i2c_iop3xx_exit (void)
 548 {
 549         platform_driver_unregister(&iop3xx_i2c_driver);
 550         return;
 551 }
 552
 553 module_init (i2c_iop3xx_init);
 554 module_exit (i2c_iop3xx_exit);
 555
 556 MODULE_AUTHOR("D-TACQ Solutions Ltd <www.d-tacq.com>");
 557 MODULE_DESCRIPTION("IOP3xx iic algorithm and driver");
 558 MODULE_LICENSE("GPL");