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/errno.h>
  38 #include <linux/platform_device.h>
  39 #include <linux/i2c.h>
  40 #include <linux/io.h>
  41 #include <linux/gpio.h>
  42
  43 #include "i2c-iop3xx.h"
  44
  45 /* global unit counter */
  46 static int i2c_id;
  47
  48 static inline unsigned char
  49 iic_cook_addr(struct i2c_msg *msg)
  50 {
  51         unsigned char addr;
  52
  53         addr = i2c_8bit_addr_from_msg(msg);
  54
  55         return addr;
  56 }
  57
  58 static void
  59 iop3xx_i2c_reset(struct i2c_algo_iop3xx_data *iop3xx_adap)
  60 {
  61         /* Follows devman 9.3 */
  62         __raw_writel(IOP3XX_ICR_UNIT_RESET, iop3xx_adap->ioaddr + CR_OFFSET);
  63         __raw_writel(IOP3XX_ISR_CLEARBITS, iop3xx_adap->ioaddr + SR_OFFSET);
  64         __raw_writel(0, iop3xx_adap->ioaddr + CR_OFFSET);
  65 }
  66
  67 static void
  68 iop3xx_i2c_enable(struct i2c_algo_iop3xx_data *iop3xx_adap)
  69 {
  70         u32 cr = IOP3XX_ICR_GCD | IOP3XX_ICR_SCLEN | IOP3XX_ICR_UE;
  71
  72         /*
  73          * Every time unit enable is asserted, GPOD needs to be cleared
  74          * on IOP3XX to avoid data corruption on the bus.
  75          */
  76 #if defined(CONFIG_ARCH_IOP32X) || defined(CONFIG_ARCH_IOP33X)
  77         if (iop3xx_adap->id == 0) {
  78                 gpio_set_value(7, 0);
  79                 gpio_set_value(6, 0);
  80         } else {
  81                 gpio_set_value(5, 0);
  82                 gpio_set_value(4, 0);
  83         }
  84 #endif
  85         /* NB SR bits not same position as CR IE bits :-( */
  86         iop3xx_adap->SR_enabled =
  87                 IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD |
  88                 IOP3XX_ISR_RXFULL | IOP3XX_ISR_TXEMPTY;
  89
  90         cr |= IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
  91                 IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE;
  92
  93         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
  94 }
  95
  96 static void
  97 iop3xx_i2c_transaction_cleanup(struct i2c_algo_iop3xx_data *iop3xx_adap)
  98 {
  99         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 100
 101         cr &= ~(IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE |
 102                 IOP3XX_ICR_MSTOP | IOP3XX_ICR_SCLEN);
 103
 104         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 105 }
 106
 107 /*
 108  * NB: the handler has to clear the source of the interrupt!
 109  * Then it passes the SR flags of interest to BH via adap data
 110  */
 111 static irqreturn_t
 112 iop3xx_i2c_irq_handler(int this_irq, void *dev_id)
 113 {
 114         struct i2c_algo_iop3xx_data *iop3xx_adap = dev_id;
 115         u32 sr = __raw_readl(iop3xx_adap->ioaddr + SR_OFFSET);
 116
 117         if ((sr &= iop3xx_adap->SR_enabled)) {
 118                 __raw_writel(sr, iop3xx_adap->ioaddr + SR_OFFSET);
 119                 iop3xx_adap->SR_received |= sr;
 120                 wake_up_interruptible(&iop3xx_adap->waitq);
 121         }
 122         return IRQ_HANDLED;
 123 }
 124
 125 /* check all error conditions, clear them , report most important */
 126 static int
 127 iop3xx_i2c_error(u32 sr)
 128 {
 129         int rc = 0;
 130
 131         if ((sr & IOP3XX_ISR_BERRD)) {
 132                 if ( !rc ) rc = -I2C_ERR_BERR;
 133         }
 134         if ((sr & IOP3XX_ISR_ALD)) {
 135                 if ( !rc ) rc = -I2C_ERR_ALD;
 136         }
 137         return rc;
 138 }
 139
 140 static inline u32
 141 iop3xx_i2c_get_srstat(struct i2c_algo_iop3xx_data *iop3xx_adap)
 142 {
 143         unsigned long flags;
 144         u32 sr;
 145
 146         spin_lock_irqsave(&iop3xx_adap->lock, flags);
 147         sr = iop3xx_adap->SR_received;
 148         iop3xx_adap->SR_received = 0;
 149         spin_unlock_irqrestore(&iop3xx_adap->lock, flags);
 150
 151         return sr;
 152 }
 153
 154 /*
 155  * sleep until interrupted, then recover and analyse the SR
 156  * saved by handler
 157  */
 158 typedef int (* compare_func)(unsigned test, unsigned mask);
 159 /* returns 1 on correct comparison */
 160
 161 static int
 162 iop3xx_i2c_wait_event(struct i2c_algo_iop3xx_data *iop3xx_adap,
 163                           unsigned flags, unsigned* status,
 164                           compare_func compare)
 165 {
 166         unsigned sr = 0;
 167         int interrupted;
 168         int done;
 169         int rc = 0;
 170
 171         do {
 172                 interrupted = wait_event_interruptible_timeout (
 173                         iop3xx_adap->waitq,
 174                         (done = compare( sr = iop3xx_i2c_get_srstat(iop3xx_adap) ,flags )),
 175                         1 * HZ
 176                         );
 177                 if ((rc = iop3xx_i2c_error(sr)) < 0) {
 178                         *status = sr;
 179                         return rc;
 180                 } else if (!interrupted) {
 181                         *status = sr;
 182                         return -ETIMEDOUT;
 183                 }
 184         } while(!done);
 185
 186         *status = sr;
 187
 188         return 0;
 189 }
 190
 191 /*
 192  * Concrete compare_funcs
 193  */
 194 static int
 195 all_bits_clear(unsigned test, unsigned mask)
 196 {
 197         return (test & mask) == 0;
 198 }
 199
 200 static int
 201 any_bits_set(unsigned test, unsigned mask)
 202 {
 203         return (test & mask) != 0;
 204 }
 205
 206 static int
 207 iop3xx_i2c_wait_tx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 208 {
 209         return iop3xx_i2c_wait_event(
 210                 iop3xx_adap,
 211                 IOP3XX_ISR_TXEMPTY | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
 212                 status, any_bits_set);
 213 }
 214
 215 static int
 216 iop3xx_i2c_wait_rx_done(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 217 {
 218         return iop3xx_i2c_wait_event(
 219                 iop3xx_adap,
 220                 IOP3XX_ISR_RXFULL | IOP3XX_ISR_ALD | IOP3XX_ISR_BERRD,
 221                 status, any_bits_set);
 222 }
 223
 224 static int
 225 iop3xx_i2c_wait_idle(struct i2c_algo_iop3xx_data *iop3xx_adap, int *status)
 226 {
 227         return iop3xx_i2c_wait_event(
 228                 iop3xx_adap, IOP3XX_ISR_UNITBUSY, status, all_bits_clear);
 229 }
 230
 231 static int
 232 iop3xx_i2c_send_target_addr(struct i2c_algo_iop3xx_data *iop3xx_adap,
 233                                 struct i2c_msg* msg)
 234 {
 235         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 236         int status;
 237         int rc;
 238
 239         /* avoid writing to my slave address (hangs on 80331),
 240          * forbidden in Intel developer manual
 241          */
 242         if (msg->addr == MYSAR) {
 243                 return -EBUSY;
 244         }
 245
 246         __raw_writel(iic_cook_addr(msg), iop3xx_adap->ioaddr + DBR_OFFSET);
 247
 248         cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
 249         cr |= IOP3XX_ICR_MSTART | IOP3XX_ICR_TBYTE;
 250
 251         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 252         rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
 253
 254         return rc;
 255 }
 256
 257 static int
 258 iop3xx_i2c_write_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char byte,
 259                                 int stop)
 260 {
 261         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 262         int status;
 263         int rc = 0;
 264
 265         __raw_writel(byte, iop3xx_adap->ioaddr + DBR_OFFSET);
 266         cr &= ~IOP3XX_ICR_MSTART;
 267         if (stop) {
 268                 cr |= IOP3XX_ICR_MSTOP;
 269         } else {
 270                 cr &= ~IOP3XX_ICR_MSTOP;
 271         }
 272         cr |= IOP3XX_ICR_TBYTE;
 273         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 274         rc = iop3xx_i2c_wait_tx_done(iop3xx_adap, &status);
 275
 276         return rc;
 277 }
 278
 279 static int
 280 iop3xx_i2c_read_byte(struct i2c_algo_iop3xx_data *iop3xx_adap, char* byte,
 281                                 int stop)
 282 {
 283         unsigned long cr = __raw_readl(iop3xx_adap->ioaddr + CR_OFFSET);
 284         int status;
 285         int rc = 0;
 286
 287         cr &= ~IOP3XX_ICR_MSTART;
 288
 289         if (stop) {
 290                 cr |= IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK;
 291         } else {
 292                 cr &= ~(IOP3XX_ICR_MSTOP | IOP3XX_ICR_NACK);
 293         }
 294         cr |= IOP3XX_ICR_TBYTE;
 295         __raw_writel(cr, iop3xx_adap->ioaddr + CR_OFFSET);
 296
 297         rc = iop3xx_i2c_wait_rx_done(iop3xx_adap, &status);
 298
 299         *byte = __raw_readl(iop3xx_adap->ioaddr + DBR_OFFSET);
 300
 301         return rc;
 302 }
 303
 304 static int
 305 iop3xx_i2c_writebytes(struct i2c_adapter *i2c_adap, const char *buf, int count)
 306 {
 307         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 308         int ii;
 309         int rc = 0;
 310
 311         for (ii = 0; rc == 0 && ii != count; ++ii)
 312                 rc = iop3xx_i2c_write_byte(iop3xx_adap, buf[ii], ii==count-1);
 313         return rc;
 314 }
 315
 316 static int
 317 iop3xx_i2c_readbytes(struct i2c_adapter *i2c_adap, char *buf, int count)
 318 {
 319         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 320         int ii;
 321         int rc = 0;
 322
 323         for (ii = 0; rc == 0 && ii != count; ++ii)
 324                 rc = iop3xx_i2c_read_byte(iop3xx_adap, &buf[ii], ii==count-1);
 325
 326         return rc;
 327 }
 328
 329 /*
 330  * Description:  This function implements combined transactions.  Combined
 331  * transactions consist of combinations of reading and writing blocks of data.
 332  * FROM THE SAME ADDRESS
 333  * Each transfer (i.e. a read or a write) is separated by a repeated start
 334  * condition.
 335  */
 336 static int
 337 iop3xx_i2c_handle_msg(struct i2c_adapter *i2c_adap, struct i2c_msg* pmsg)
 338 {
 339         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 340         int rc;
 341
 342         rc = iop3xx_i2c_send_target_addr(iop3xx_adap, pmsg);
 343         if (rc < 0) {
 344                 return rc;
 345         }
 346
 347         if ((pmsg->flags&I2C_M_RD)) {
 348                 return iop3xx_i2c_readbytes(i2c_adap, pmsg->buf, pmsg->len);
 349         } else {
 350                 return iop3xx_i2c_writebytes(i2c_adap, pmsg->buf, pmsg->len);
 351         }
 352 }
 353
 354 /*
 355  * master_xfer() - main read/write entry
 356  */
 357 static int
 358 iop3xx_i2c_master_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs,
 359                                 int num)
 360 {
 361         struct i2c_algo_iop3xx_data *iop3xx_adap = i2c_adap->algo_data;
 362         int im = 0;
 363         int ret = 0;
 364         int status;
 365
 366         iop3xx_i2c_wait_idle(iop3xx_adap, &status);
 367         iop3xx_i2c_reset(iop3xx_adap);
 368         iop3xx_i2c_enable(iop3xx_adap);
 369
 370         for (im = 0; ret == 0 && im != num; im++) {
 371                 ret = iop3xx_i2c_handle_msg(i2c_adap, &msgs[im]);
 372         }
 373
 374         iop3xx_i2c_transaction_cleanup(iop3xx_adap);
 375
 376         if(ret)
 377                 return ret;
 378
 379         return im;
 380 }
 381
 382 static u32
 383 iop3xx_i2c_func(struct i2c_adapter *adap)
 384 {
 385         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 386 }
 387
 388 static const struct i2c_algorithm iop3xx_i2c_algo = {
 389         .master_xfer    = iop3xx_i2c_master_xfer,
 390         .functionality  = iop3xx_i2c_func,
 391 };
 392
 393 static int
 394 iop3xx_i2c_remove(struct platform_device *pdev)
 395 {
 396         struct i2c_adapter *padapter = platform_get_drvdata(pdev);
 397         struct i2c_algo_iop3xx_data *adapter_data =
 398                 (struct i2c_algo_iop3xx_data *)padapter->algo_data;
 399         struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 400         unsigned long cr = __raw_readl(adapter_data->ioaddr + CR_OFFSET);
 401
 402         /*
 403          * Disable the actual HW unit
 404          */
 405         cr &= ~(IOP3XX_ICR_ALD_IE | IOP3XX_ICR_BERR_IE |
 406                 IOP3XX_ICR_RXFULL_IE | IOP3XX_ICR_TXEMPTY_IE);
 407         __raw_writel(cr, adapter_data->ioaddr + CR_OFFSET);
 408
 409         iounmap(adapter_data->ioaddr);
 410         release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
 411         kfree(adapter_data);
 412         kfree(padapter);
 413
 414         return 0;
 415 }
 416
 417 static int
 418 iop3xx_i2c_probe(struct platform_device *pdev)
 419 {
 420         struct resource *res;
 421         int ret, irq;
 422         struct i2c_adapter *new_adapter;
 423         struct i2c_algo_iop3xx_data *adapter_data;
 424
 425         new_adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
 426         if (!new_adapter) {
 427                 ret = -ENOMEM;
 428                 goto out;
 429         }
 430
 431         adapter_data = kzalloc(sizeof(struct i2c_algo_iop3xx_data), GFP_KERNEL);
 432         if (!adapter_data) {
 433                 ret = -ENOMEM;
 434                 goto free_adapter;
 435         }
 436
 437         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 438         if (!res) {
 439                 ret = -ENODEV;
 440                 goto free_both;
 441         }
 442
 443         if (!request_mem_region(res->start, IOP3XX_I2C_IO_SIZE, pdev->name)) {
 444                 ret = -EBUSY;
 445                 goto free_both;
 446         }
 447
 448         /* set the adapter enumeration # */
 449         adapter_data->id = i2c_id++;
 450
 451         adapter_data->ioaddr = ioremap(res->start, IOP3XX_I2C_IO_SIZE);
 452         if (!adapter_data->ioaddr) {
 453                 ret = -ENOMEM;
 454                 goto release_region;
 455         }
 456
 457         irq = platform_get_irq(pdev, 0);
 458         if (irq < 0) {
 459                 ret = -ENXIO;
 460                 goto unmap;
 461         }
 462         ret = request_irq(irq, iop3xx_i2c_irq_handler, 0,
 463                                 pdev->name, adapter_data);
 464
 465         if (ret) {
 466                 ret = -EIO;
 467                 goto unmap;
 468         }
 469
 470         memcpy(new_adapter->name, pdev->name, strlen(pdev->name));
 471         new_adapter->owner = THIS_MODULE;
 472         new_adapter->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 473         new_adapter->dev.parent = &pdev->dev;
 474         new_adapter->nr = pdev->id;
 475
 476         /*
 477          * Default values...should these come in from board code?
 478          */
 479         new_adapter->timeout = HZ;
 480         new_adapter->algo = &iop3xx_i2c_algo;
 481
 482         init_waitqueue_head(&adapter_data->waitq);
 483         spin_lock_init(&adapter_data->lock);
 484
 485         iop3xx_i2c_reset(adapter_data);
 486         iop3xx_i2c_enable(adapter_data);
 487
 488         platform_set_drvdata(pdev, new_adapter);
 489         new_adapter->algo_data = adapter_data;
 490
 491         i2c_add_numbered_adapter(new_adapter);
 492
 493         return 0;
 494
 495 unmap:
 496         iounmap(adapter_data->ioaddr);
 497
 498 release_region:
 499         release_mem_region(res->start, IOP3XX_I2C_IO_SIZE);
 500
 501 free_both:
 502         kfree(adapter_data);
 503
 504 free_adapter:
 505         kfree(new_adapter);
 506
 507 out:
 508         return ret;
 509 }
 510
 511
 512 static struct platform_driver iop3xx_i2c_driver = {
 513         .probe          = iop3xx_i2c_probe,
 514         .remove         = iop3xx_i2c_remove,
 515         .driver         = {
 516                 .name   = "IOP3xx-I2C",
 517         },
 518 };
 519
 520 module_platform_driver(iop3xx_i2c_driver);
 521
 522 MODULE_AUTHOR("D-TACQ Solutions Ltd <www.d-tacq.com>");
 523 MODULE_DESCRIPTION("IOP3xx iic algorithm and driver");
 524 MODULE_LICENSE("GPL");
 525 MODULE_ALIAS("platform:IOP3xx-I2C");