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 IOP3XX to avoid data corruption on the bus.
  86          */
  87 #ifdef CONFIG_PLAT_IOP
  88         if (iop3xx_adap->id == 0) {
  89                 gpio_line_set(IOP3XX_GPIO_LINE(7), GPIO_LOW);
  90                 gpio_line_set(IOP3XX_GPIO_LINE(6), GPIO_LOW);
  91         } else {
  92                 gpio_line_set(IOP3XX_GPIO_LINE(5), GPIO_LOW);
  93                 gpio_line_set(IOP3XX_GPIO_LINE(4), GPIO_LOW);
  94         }
  95 #endif
  96         /* NB SR bits not same position as CR IE bits :-( */
  97         iop3xx_adap->SR_enabled =
  98                 IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD |
  99                 IOP3XX_ISR_RXFULL | IOP3XX_ISR_TXEMPTY;
 100
 101         cr |= IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
 102                 IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE;
 103
 104         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 105 }
 106
 107 static void
 108 iop3xx_i2c_transaction_cleanup(struct i2c_algo_iop3xx_data *iop3xx_adap)
 109 {
 110         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 111
 112         cr &= ~(IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE |
 113                 IOP3XX_ICR_MSTOP | IOP3XX_ICR_SCLEN);
 114
 115         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 116 }
 117
 118 /*
 119  * NB: the handler has to clear the source of the interrupt!
 120  * Then it passes the SR flags of interest to BH via adap data
 121  */
 122 static irqreturn_t
 123 iop3xx_i2c_irq_handler(int this_irq, void *dev_id)
 124 {
 125         struct i2c_algo_iop3xx_data *iop3xx_adap = dev_id;
 126         u32 sr = __raw_readl(iop3xx_adap->ioaddr + SR_OFFSET);
 127
 128         if ((sr &= iop3xx_adap->SR_enabled)) {
 129                 __raw_writel(sr, iop3xx_adap->ioaddr + SR_OFFSET);
 130                 iop3xx_adap->SR_received |= sr;
 131                 wake_up_interruptible(&iop3xx_adap->waitq);
 132         }
 133         return IRQ_HANDLED;
 134 }
 135
 136 /* check all error conditions, clear them , report most important */
 137 static int
 138 iop3xx_i2c_error(u32 sr)
 139 {
 140         int rc = 0;
 141
 142         if ((sr & IOP3XX_ISR_BERRD)) {
 143                 if ( !rc ) rc = -I2C_ERR_BERR;
 144         }
 145         if ((sr & IOP3XX_ISR_ALD)) {
 146                 if ( !rc ) rc = -I2C_ERR_ALD;
 147         }
 148         return rc;
 149 }
 150
 151 static inline u32
 152 iop3xx_i2c_get_srstat(struct i2c_algo_iop3xx_data *iop3xx_adap)
 153 {
 154         unsigned long flags;
 155         u32 sr;
 156
 157         spin_lock_irqsave(&iop3xx_adap->lock, flags);
 158         sr = iop3xx_adap->SR_received;
 159         iop3xx_adap->SR_received = 0;
 160         spin_unlock_irqrestore(&iop3xx_adap->lock, flags);
 161
 162         return sr;
 163 }
 164
 165 /*
 166  * sleep until interrupted, then recover and analyse the SR
 167  * saved by handler
 168  */
 169 typedef int (* compare_func)(unsigned test, unsigned mask);
 170 /* returns 1 on correct comparison */
 171
 172 static int
 173 iop3xx_i2c_wait_event(struct i2c_algo_iop3xx_data *iop3xx_adap,
 174                           unsigned flags, unsigned* status,
 175                           compare_func compare)
 176 {
 177         unsigned sr = 0;
 178         int interrupted;
 179         int done;
 180         int rc = 0;
 181
 182         do {
 183                 interrupted = wait_event_interruptible_timeout (
 184                         iop3xx_adap->waitq,
 185                         (done = compare( sr = iop3xx_i2c_get_srstat(iop3xx_adap) ,flags )),
 186                         1 * HZ;
 187                         );
 188                 if ((rc = iop3xx_i2c_error(sr)) < 0) {
 189                         *status = sr;
 190                         return rc;
 191                 } else if (!interrupted) {
 192                         *status = sr;
 193                         return -ETIMEDOUT;
 194                 }
 195         } while(!done);
 196
 197         *status = sr;
 198
 199         return 0;
 200 }
 201
 202 /*
 203  * Concrete compare_funcs
 204  */
 205 static int
 206 all_bits_clear(unsigned test, unsigned mask)
 207 {
 208         return (test & mask) == 0;
 209 }
 210
 211 static int
 212 any_bits_set(unsigned test, unsigned mask)
 213 {
 214         return (test & mask) != 0;
 215 }
 216
 217 static int
 218 iop3xx_i2c_wait_tx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 219 {
 220         return iop3xx_i2c_wait_event(
 221                 iop3xx_adap,
 222                 IOP3XX_ISR_TXEMPTY | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
 223                 status, any_bits_set);
 224 }
 225
 226 static int
 227 iop3xx_i2c_wait_rx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 228 {
 229         return iop3xx_i2c_wait_event(
 230                 iop3xx_adap,
 231                 IOP3XX_ISR_RXFULL | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
 232                 status, any_bits_set);
 233 }
 234
 235 static int
 236 iop3xx_i2c_wait_idle(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 237 {
 238         return iop3xx_i2c_wait_event(
 239                 iop3xx_adap, IOP3XX_ISR_UNITBUSY, status, all_bits_clear);
 240 }
 241
 242 static int
 243 iop3xx_i2c_send_target_addr(struct i2c_algo_iop3xx_data *iop3xx_adap,
 244                                 struct i2c_msg* msg)
 245 {
 246         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 247         int status;
 248         int rc;
 249
 250         /* avoid writing to my slave address (hangs on 80331),
 251          * forbidden in Intel developer manual
 252          */
 253         if (msg->addr == MYSAR) {
 254                 return -EBUSY;
 255         }
 256
 257         __raw_writel(iic_cook_addr(msg), iop3xx_adap->ioaddr + DBR_OFFSET);
 258
 259         cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
 260         cr |= IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE;
 261
 262         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 263         rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
 264
 265         return rc;
 266 }
 267
 268 static int
 269 iop3xx_i2c_write_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char byte,
 270                                 int stop)
 271 {
 272         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 273         int status;
 274         int rc = 0;
 275
 276         __raw_writel(byte, iop3xx_adap->ioaddr + DBR_OFFSET);
 277         cr &= ~IOP3XX_ICR_MSTART;
 278         if (stop) {
 279                 cr |= IOP3XX_ICR_MSTOP;
 280         } else {
 281                 cr &= ~IOP3XX_ICR_MSTOP;
 282         }
 283         cr |= IOP3XX_ICR_TBYTE;
 284         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 285         rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
 286
 287         return rc;
 288 }
 289
 290 static int
 291 iop3xx_i2c_read_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char* byte,
 292                                 int stop)
 293 {
 294         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 295         int status;
 296         int rc = 0;
 297
 298         cr &= ~IOP3XX_ICR_MSTART;
 299
 300         if (stop) {
 301                 cr |= IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK;
 302         } else {
 303                 cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
 304         }
 305         cr |= IOP3XX_ICR_TBYTE;
 306         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 307
 308         rc = iop3xx_i2c_wait_rx_done(iop3xx_adap, &status);
 309
 310         *byte = __raw_readl(iop3xx_adap->ioaddr + DBR_OFFSET);
 311
 312         return rc;
 313 }
 314
 315 static int
 316 iop3xx_i2c_writebytes(struct i2c_adapter *i2c_adap, const char *buf, int count)
 317 {
 318         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 319         int ii;
 320         int rc = 0;
 321
 322         for (ii = 0; rc == 0 && ii != count; ++ii)
 323                 rc = iop3xx_i2c_write_byte(iop3xx_adap, buf[ii], ii==count-1);
 324         return rc;
 325 }
 326
 327 static int
 328 iop3xx_i2c_readbytes(struct i2c_adapter *i2c_adap, char *buf, int count)
 329 {
 330         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 331         int ii;
 332         int rc = 0;
 333
 334         for (ii = 0; rc == 0 && ii != count; ++ii)
 335                 rc = iop3xx_i2c_read_byte(iop3xx_adap, &buf[ii], ii==count-1);
 336
 337         return rc;
 338 }
 339
 340 /*
 341  * Description:  This function implements combined transactions.  Combined
 342  * transactions consist of combinations of reading and writing blocks of data.
 343  * FROM THE SAME ADDRESS
 344  * Each transfer (i.e. a read or a write) is separated by a repeated start
 345  * condition.
 346  */
 347 static int
 348 iop3xx_i2c_handle_msg(struct i2c_adapter *i2c_adap, struct i2c_msg* pmsg)
 349 {
 350         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 351         int rc;
 352
 353         rc = iop3xx_i2c_send_target_addr(iop3xx_adap, pmsg);
 354         if (rc < 0) {
 355                 return rc;
 356         }
 357
 358         if ((pmsg->flags&I2C_M_RD)) {
 359                 return iop3xx_i2c_readbytes(i2c_adap, pmsg->buf, pmsg->len);
 360         } else {
 361                 return iop3xx_i2c_writebytes(i2c_adap, pmsg->buf, pmsg->len);
 362         }
 363 }
 364
 365 /*
 366  * master_xfer() - main read/write entry
 367  */
 368 static int
 369 iop3xx_i2c_master_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
 370                                 int num)
 371 {
 372         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 373         int im = 0;
 374         int ret = 0;
 375         int status;
 376
 377         iop3xx_i2c_wait_idle(iop3xx_adap, &status);
 378         iop3xx_i2c_reset(iop3xx_adap);
 379         iop3xx_i2c_enable(iop3xx_adap);
 380
 381         for (im = 0; ret == 0 && im != num; im++) {
 382                 ret = iop3xx_i2c_handle_msg(i2c_adap, &msgs[im]);
 383         }
 384
 385         iop3xx_i2c_transaction_cleanup(iop3xx_adap);
 386
 387         if(ret)
 388                 return ret;
 389
 390         return im;
 391 }
 392
 393 static int
 394 iop3xx_i2c_algo_control(struct i2c_adapter *adapter, unsigned int cmd,
 395                         unsigned long arg)
 396 {
 397         return 0;
 398 }
 399
 400 static u32
 401 iop3xx_i2c_func(struct i2c_adapter *adap)
 402 {
 403         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 404 }
 405
 406 static const struct i2c_algorithm iop3xx_i2c_algo = {
 407         .master_xfer    = iop3xx_i2c_master_xfer,
 408         .algo_control   = iop3xx_i2c_algo_control,
 409         .functionality  = iop3xx_i2c_func,
 410 };
 411
 412 static int
 413 iop3xx_i2c_remove(struct platform_device *pdev)
 414 {
 415         struct i2c_adapter *padapter = platform_get_drvdata(pdev);
 416         struct i2c_algo_iop3xx_data *adapter_data =
 417                 (struct i2c_algo_iop3xx_data *)padapter->algo_data;
 418         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 419         unsigned long cr = __raw_readl(adapter_data->ioaddr + CR_OFFSET);
 420
 421         /*
 422          * Disable the actual HW unit
 423          */
 424         cr &= ~(IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
 425                 IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE);
 426         __raw_writel(cr, adapter_data->ioaddr + CR_OFFSET);
 427
 428         iounmap((void __iomem*)adapter_data->ioaddr);
 429         release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
 430         kfree(adapter_data);
 431         kfree(padapter);
 432
 433         platform_set_drvdata(pdev, NULL);
 434
 435         return 0;
 436 }
 437
 438 static int
 439 iop3xx_i2c_probe(struct platform_device *pdev)
 440 {
 441         struct resource *res;
 442         int ret, irq;
 443         struct i2c_adapter *new_adapter;
 444         struct i2c_algo_iop3xx_data *adapter_data;
 445
 446         new_adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
 447         if (!new_adapter) {
 448                 ret = -ENOMEM;
 449                 goto out;
 450         }
 451
 452         adapter_data = kzalloc(sizeof(struct i2c_algo_iop3xx_data), GFP_KERNEL);
 453         if (!adapter_data) {
 454                 ret = -ENOMEM;
 455                 goto free_adapter;
 456         }
 457
 458         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 459         if (!res) {
 460                 ret = -ENODEV;
 461                 goto free_both;
 462         }
 463
 464         if (!request_mem_region(res->start, IOP3XX_I2C_IO_SIZE, pdev->name)) {
 465                 ret = -EBUSY;
 466                 goto free_both;
 467         }
 468
 469         /* set the adapter enumeration # */
 470         adapter_data->id = i2c_id++;
 471
 472         adapter_data->ioaddr = (u32)ioremap(res->start, IOP3XX_I2C_IO_SIZE);
 473         if (!adapter_data->ioaddr) {
 474                 ret = -ENOMEM;
 475                 goto release_region;
 476         }
 477
 478         irq = platform_get_irq(pdev, 0);
 479         if (irq < 0) {
 480                 ret = -ENXIO;
 481                 goto unmap;
 482         }
 483         ret = request_irq(irq, iop3xx_i2c_irq_handler, 0,
 484                                 pdev->name, adapter_data);
 485
 486         if (ret) {
 487                 ret = -EIO;
 488                 goto unmap;
 489         }
 490
 491         memcpy(new_adapter->name, pdev->name, strlen(pdev->name));
 492         new_adapter->id = I2C_HW_IOP3XX;
 493         new_adapter->owner = THIS_MODULE;
 494         new_adapter->class = I2C_CLASS_HWMON,
 495         new_adapter->dev.parent = &pdev->dev;
 496
 497         /*
 498          * Default values...should these come in from board code?
 499          */
 500         new_adapter->timeout = 100;
 501         new_adapter->retries = 3;
 502         new_adapter->algo = &iop3xx_i2c_algo;
 503
 504         init_waitqueue_head(&adapter_data->waitq);
 505         spin_lock_init(&adapter_data->lock);
 506
 507         iop3xx_i2c_reset(adapter_data);
 508         iop3xx_i2c_enable(adapter_data);
 509
 510         platform_set_drvdata(pdev, new_adapter);
 511         new_adapter->algo_data = adapter_data;
 512
 513         i2c_add_adapter(new_adapter);
 514
 515         return 0;
 516
 517 unmap:
 518         iounmap((void __iomem*)adapter_data->ioaddr);
 519
 520 release_region:
 521         release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
 522
 523 free_both:
 524         kfree(adapter_data);
 525
 526 free_adapter:
 527         kfree(new_adapter);
 528
 529 out:
 530         return ret;
 531 }
 532
 533
 534 static struct platform_driver iop3xx_i2c_driver = {
 535         .probe          = iop3xx_i2c_probe,
 536         .remove         = iop3xx_i2c_remove,
 537         .driver         = {
 538                 .owner  = THIS_MODULE,
 539                 .name   = "IOP3xx-I2C",
 540         },
 541 };
 542
 543 static int __init
 544 i2c_iop3xx_init (void)
 545 {
 546         return platform_driver_register(&iop3xx_i2c_driver);
 547 }
 548
 549 static void __exit
 550 i2c_iop3xx_exit (void)
 551 {
 552         platform_driver_unregister(&iop3xx_i2c_driver);
 553         return;
 554 }
 555
 556 module_init (i2c_iop3xx_init);
 557 module_exit (i2c_iop3xx_exit);
 558
 559 MODULE_AUTHOR("D-TACQ Solutions Ltd <www.d-tacq.com>");
 560 MODULE_DESCRIPTION("IOP3xx iic algorithm and driver");
 561 MODULE_LICENSE("GPL");