drivers/i2c/busses/i2c-davinci.c

   1 /*
   2  * TI DAVINCI I2C adapter driver.
   3  *
   4  * Copyright (C) 2006 Texas Instruments.
   5  * Copyright (C) 2007 MontaVista Software Inc.
   6  *
   7  * Updated by Vinod & Sudhakar Feb 2005
   8  *
   9  * ----------------------------------------------------------------------------
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  24  * ----------------------------------------------------------------------------
  25  *
  26  */
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/delay.h>
  30 #include <linux/i2c.h>
  31 #include <linux/clk.h>
  32 #include <linux/errno.h>
  33 #include <linux/sched.h>
  34 #include <linux/err.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/platform_device.h>
  37 #include <linux/io.h>
  38
  39 #include <asm/hardware.h>
  40 #include <asm/mach-types.h>
  41
  42 #include <asm/arch/i2c.h>
  43
  44 /* ----- global defines ----------------------------------------------- */
  45
  46 #define DAVINCI_I2C_TIMEOUT     (1*HZ)
  47 #define I2C_DAVINCI_INTR_ALL    (DAVINCI_I2C_IMR_AAS | \
  48                                  DAVINCI_I2C_IMR_SCD | \
  49                                  DAVINCI_I2C_IMR_ARDY | \
  50                                  DAVINCI_I2C_IMR_NACK | \
  51                                  DAVINCI_I2C_IMR_AL)
  52
  53 #define DAVINCI_I2C_OAR_REG     0x00
  54 #define DAVINCI_I2C_IMR_REG     0x04
  55 #define DAVINCI_I2C_STR_REG     0x08
  56 #define DAVINCI_I2C_CLKL_REG    0x0c
  57 #define DAVINCI_I2C_CLKH_REG    0x10
  58 #define DAVINCI_I2C_CNT_REG     0x14
  59 #define DAVINCI_I2C_DRR_REG     0x18
  60 #define DAVINCI_I2C_SAR_REG     0x1c
  61 #define DAVINCI_I2C_DXR_REG     0x20
  62 #define DAVINCI_I2C_MDR_REG     0x24
  63 #define DAVINCI_I2C_IVR_REG     0x28
  64 #define DAVINCI_I2C_EMDR_REG    0x2c
  65 #define DAVINCI_I2C_PSC_REG     0x30
  66
  67 #define DAVINCI_I2C_IVR_AAS     0x07
  68 #define DAVINCI_I2C_IVR_SCD     0x06
  69 #define DAVINCI_I2C_IVR_XRDY    0x05
  70 #define DAVINCI_I2C_IVR_RDR     0x04
  71 #define DAVINCI_I2C_IVR_ARDY    0x03
  72 #define DAVINCI_I2C_IVR_NACK    0x02
  73 #define DAVINCI_I2C_IVR_AL      0x01
  74
  75 #define DAVINCI_I2C_STR_BB      (1 << 12)
  76 #define DAVINCI_I2C_STR_RSFULL  (1 << 11)
  77 #define DAVINCI_I2C_STR_SCD     (1 << 5)
  78 #define DAVINCI_I2C_STR_ARDY    (1 << 2)
  79 #define DAVINCI_I2C_STR_NACK    (1 << 1)
  80 #define DAVINCI_I2C_STR_AL      (1 << 0)
  81
  82 #define DAVINCI_I2C_MDR_NACK    (1 << 15)
  83 #define DAVINCI_I2C_MDR_STT     (1 << 13)
  84 #define DAVINCI_I2C_MDR_STP     (1 << 11)
  85 #define DAVINCI_I2C_MDR_MST     (1 << 10)
  86 #define DAVINCI_I2C_MDR_TRX     (1 << 9)
  87 #define DAVINCI_I2C_MDR_XA      (1 << 8)
  88 #define DAVINCI_I2C_MDR_IRS     (1 << 5)
  89
  90 #define DAVINCI_I2C_IMR_AAS     (1 << 6)
  91 #define DAVINCI_I2C_IMR_SCD     (1 << 5)
  92 #define DAVINCI_I2C_IMR_XRDY    (1 << 4)
  93 #define DAVINCI_I2C_IMR_RRDY    (1 << 3)
  94 #define DAVINCI_I2C_IMR_ARDY    (1 << 2)
  95 #define DAVINCI_I2C_IMR_NACK    (1 << 1)
  96 #define DAVINCI_I2C_IMR_AL      (1 << 0)
  97
  98 #define MOD_REG_BIT(val, mask, set) do { \
  99         if (set) { \
 100                 val |= mask; \
 101         } else { \
 102                 val &= ~mask; \
 103         } \
 104 } while (0)
 105
 106 struct davinci_i2c_dev {
 107         struct device           *dev;
 108         void __iomem            *base;
 109         struct completion       cmd_complete;
 110         struct clk              *clk;
 111         int                     cmd_err;
 112         u8                      *buf;
 113         size_t                  buf_len;
 114         int                     irq;
 115         struct i2c_adapter      adapter;
 116 };
 117
 118 /* default platform data to use if not supplied in the platform_device */
 119 static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
 120         .bus_freq       = 100,
 121         .bus_delay      = 0,
 122 };
 123
 124 static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
 125                                          int reg, u16 val)
 126 {
 127         __raw_writew(val, i2c_dev->base + reg);
 128 }
 129
 130 static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
 131 {
 132         return __raw_readw(i2c_dev->base + reg);
 133 }
 134
 135 /*
 136  * This functions configures I2C and brings I2C out of reset.
 137  * This function is called during I2C init function. This function
 138  * also gets called if I2C encounters any errors.
 139  */
 140 static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 141 {
 142         struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
 143         u16 psc;
 144         u32 clk;
 145         u32 clkh;
 146         u32 clkl;
 147         u32 input_clock = clk_get_rate(dev->clk);
 148         u16 w;
 149
 150         if (!pdata)
 151                 pdata = &davinci_i2c_platform_data_default;
 152
 153         /* put I2C into reset */
 154         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 155         MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 0);
 156         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 157
 158         /* NOTE: I2C Clock divider programming info
 159          * As per I2C specs the following formulas provide prescaler
 160          * and low/high divider values
 161          * input clk --> PSC Div -----------> ICCL/H Div --> output clock
 162          *                       module clk
 163          *
 164          * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
 165          *
 166          * Thus,
 167          * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
 168          *
 169          * where if PSC == 0, d = 7,
 170          *       if PSC == 1, d = 6
 171          *       if PSC > 1 , d = 5
 172          */
 173
 174         psc = 26; /* To get 1MHz clock */
 175
 176         clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - 10;
 177         clkh = (50 * clk) / 100;
 178         clkl = clk - clkh;
 179
 180         davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
 181         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
 182         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
 183
 184         dev_dbg(dev->dev, "CLK  = %d\n", clk);
 185         dev_dbg(dev->dev, "PSC  = %d\n",
 186                 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
 187         dev_dbg(dev->dev, "CLKL = %d\n",
 188                 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
 189         dev_dbg(dev->dev, "CLKH = %d\n",
 190                 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
 191
 192         /* Take the I2C module out of reset: */
 193         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 194         MOD_REG_BIT(w, DAVINCI_I2C_MDR_IRS, 1);
 195         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 196
 197         /* Enable interrupts */
 198         davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
 199
 200         return 0;
 201 }
 202
 203 /*
 204  * Waiting for bus not busy
 205  */
 206 static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
 207                                          char allow_sleep)
 208 {
 209         unsigned long timeout;
 210
 211         timeout = jiffies + DAVINCI_I2C_TIMEOUT;
 212         while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
 213                & DAVINCI_I2C_STR_BB) {
 214                 if (time_after(jiffies, timeout)) {
 215                         dev_warn(dev->dev,
 216                                  "timeout waiting for bus ready\n");
 217                         return -ETIMEDOUT;
 218                 }
 219                 if (allow_sleep)
 220                         schedule_timeout(1);
 221         }
 222
 223         return 0;
 224 }
 225
 226 /*
 227  * Low level master read/write transaction. This function is called
 228  * from i2c_davinci_xfer.
 229  */
 230 static int
 231 i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 232 {
 233         struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 234         struct davinci_i2c_platform_data *pdata = dev->dev->platform_data;
 235         u32 flag;
 236         u32 stat;
 237         u16 w;
 238         int r;
 239
 240         if (msg->len == 0)
 241                 return -EINVAL;
 242
 243         if (!pdata)
 244                 pdata = &davinci_i2c_platform_data_default;
 245         /* Introduce a delay, required for some boards (e.g Davinci EVM) */
 246         if (pdata->bus_delay)
 247                 udelay(pdata->bus_delay);
 248
 249         /* set the slave address */
 250         davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
 251
 252         dev->buf = msg->buf;
 253         dev->buf_len = msg->len;
 254
 255         davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
 256
 257         init_completion(&dev->cmd_complete);
 258         dev->cmd_err = 0;
 259
 260         /* Clear any pending interrupts by reading the IVR */
 261         stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG);
 262
 263         /* Take I2C out of reset, configure it as master and set the
 264          * start bit */
 265         flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST | DAVINCI_I2C_MDR_STT;
 266
 267         /* if the slave address is ten bit address, enable XA bit */
 268         if (msg->flags & I2C_M_TEN)
 269                 flag |= DAVINCI_I2C_MDR_XA;
 270         if (!(msg->flags & I2C_M_RD))
 271                 flag |= DAVINCI_I2C_MDR_TRX;
 272         if (stop)
 273                 flag |= DAVINCI_I2C_MDR_STP;
 274
 275         /* Enable receive or transmit interrupts */
 276         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
 277         if (msg->flags & I2C_M_RD)
 278                 MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 1);
 279         else
 280                 MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1);
 281         davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
 282
 283         /* write the data into mode register */
 284         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 285
 286         r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
 287                                                       DAVINCI_I2C_TIMEOUT);
 288         dev->buf_len = 0;
 289         if (r < 0)
 290                 return r;
 291
 292         if (r == 0) {
 293                 dev_err(dev->dev, "controller timed out\n");
 294                 i2c_davinci_init(dev);
 295                 return -ETIMEDOUT;
 296         }
 297
 298         /* no error */
 299         if (likely(!dev->cmd_err))
 300                 return msg->len;
 301
 302         /* We have an error */
 303         if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
 304                 i2c_davinci_init(dev);
 305                 return -EIO;
 306         }
 307
 308         if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
 309                 if (msg->flags & I2C_M_IGNORE_NAK)
 310                         return msg->len;
 311                 if (stop) {
 312                         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 313                         MOD_REG_BIT(w, DAVINCI_I2C_MDR_STP, 1);
 314                         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 315                 }
 316                 return -EREMOTEIO;
 317         }
 318         return -EIO;
 319 }
 320
 321 /*
 322  * Prepare controller for a transaction and call i2c_davinci_xfer_msg
 323  */
 324 static int
 325 i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 326 {
 327         struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 328         int i;
 329         int ret;
 330
 331         dev_dbg(dev->dev, "%s: msgs: %d\n", __FUNCTION__, num);
 332
 333         ret = i2c_davinci_wait_bus_not_busy(dev, 1);
 334         if (ret < 0) {
 335                 dev_warn(dev->dev, "timeout waiting for bus ready\n");
 336                 return ret;
 337         }
 338
 339         for (i = 0; i < num; i++) {
 340                 ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
 341                 if (ret < 0)
 342                         return ret;
 343         }
 344
 345         dev_dbg(dev->dev, "%s:%d ret: %d\n", __FUNCTION__, __LINE__, ret);
 346
 347         return num;
 348 }
 349
 350 static u32 i2c_davinci_func(struct i2c_adapter *adap)
 351 {
 352         return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
 353 }
 354
 355 /*
 356  * Interrupt service routine. This gets called whenever an I2C interrupt
 357  * occurs.
 358  */
 359 static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
 360 {
 361         struct davinci_i2c_dev *dev = dev_id;
 362         u32 stat;
 363         int count = 0;
 364         u16 w;
 365
 366         while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
 367                 dev_dbg(dev->dev, "%s: stat=0x%x\n", __FUNCTION__, stat);
 368                 if (count++ == 100) {
 369                         dev_warn(dev->dev, "Too much work in one IRQ\n");
 370                         break;
 371                 }
 372
 373                 switch (stat) {
 374                 case DAVINCI_I2C_IVR_AL:
 375                         dev->cmd_err |= DAVINCI_I2C_STR_AL;
 376                         complete(&dev->cmd_complete);
 377                         break;
 378
 379                 case DAVINCI_I2C_IVR_NACK:
 380                         dev->cmd_err |= DAVINCI_I2C_STR_NACK;
 381                         complete(&dev->cmd_complete);
 382                         break;
 383
 384                 case DAVINCI_I2C_IVR_ARDY:
 385                         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG);
 386                         MOD_REG_BIT(w, DAVINCI_I2C_STR_ARDY, 1);
 387                         davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, w);
 388                         complete(&dev->cmd_complete);
 389                         break;
 390
 391                 case DAVINCI_I2C_IVR_RDR:
 392                         if (dev->buf_len) {
 393                                 *dev->buf++ =
 394                                     davinci_i2c_read_reg(dev,
 395                                                          DAVINCI_I2C_DRR_REG);
 396                                 dev->buf_len--;
 397                                 if (dev->buf_len)
 398                                         continue;
 399
 400                                 w = davinci_i2c_read_reg(dev,
 401                                                          DAVINCI_I2C_STR_REG);
 402                                 MOD_REG_BIT(w, DAVINCI_I2C_IMR_RRDY, 0);
 403                                 davinci_i2c_write_reg(dev,
 404                                                       DAVINCI_I2C_STR_REG,
 405                                                       w);
 406                         } else
 407                                 dev_err(dev->dev, "RDR IRQ while no "
 408                                         "data requested\n");
 409                         break;
 410
 411                 case DAVINCI_I2C_IVR_XRDY:
 412                         if (dev->buf_len) {
 413                                 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
 414                                                       *dev->buf++);
 415                                 dev->buf_len--;
 416                                 if (dev->buf_len)
 417                                         continue;
 418
 419                                 w = davinci_i2c_read_reg(dev,
 420                                                          DAVINCI_I2C_IMR_REG);
 421                                 MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 0);
 422                                 davinci_i2c_write_reg(dev,
 423                                                       DAVINCI_I2C_IMR_REG,
 424                                                       w);
 425                         } else
 426                                 dev_err(dev->dev, "TDR IRQ while no data to "
 427                                         "send\n");
 428                         break;
 429
 430                 case DAVINCI_I2C_IVR_SCD:
 431                         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG);
 432                         MOD_REG_BIT(w, DAVINCI_I2C_STR_SCD, 1);
 433                         davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, w);
 434                         complete(&dev->cmd_complete);
 435                         break;
 436
 437                 case DAVINCI_I2C_IVR_AAS:
 438                         dev_warn(dev->dev, "Address as slave interrupt\n");
 439                 }/* switch */
 440         }/* while */
 441
 442         return count ? IRQ_HANDLED : IRQ_NONE;
 443 }
 444
 445 static struct i2c_algorithm i2c_davinci_algo = {
 446         .master_xfer    = i2c_davinci_xfer,
 447         .functionality  = i2c_davinci_func,
 448 };
 449
 450 static int davinci_i2c_probe(struct platform_device *pdev)
 451 {
 452         struct davinci_i2c_dev *dev;
 453         struct i2c_adapter *adap;
 454         struct resource *mem, *irq, *ioarea;
 455         int r;
 456
 457         /* NOTE: driver uses the static register mapping */
 458         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 459         if (!mem) {
 460                 dev_err(&pdev->dev, "no mem resource?\n");
 461                 return -ENODEV;
 462         }
 463
 464         irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 465         if (!irq) {
 466                 dev_err(&pdev->dev, "no irq resource?\n");
 467                 return -ENODEV;
 468         }
 469
 470         ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
 471                                     pdev->name);
 472         if (!ioarea) {
 473                 dev_err(&pdev->dev, "I2C region already claimed\n");
 474                 return -EBUSY;
 475         }
 476
 477         dev = kzalloc(sizeof(struct davinci_i2c_dev), GFP_KERNEL);
 478         if (!dev) {
 479                 r = -ENOMEM;
 480                 goto err_release_region;
 481         }
 482
 483         dev->dev = get_device(&pdev->dev);
 484         dev->irq = irq->start;
 485         platform_set_drvdata(pdev, dev);
 486
 487         dev->clk = clk_get(&pdev->dev, "I2CCLK");
 488         if (IS_ERR(dev->clk)) {
 489                 r = -ENODEV;
 490                 goto err_free_mem;
 491         }
 492         clk_enable(dev->clk);
 493
 494         dev->base = (void __iomem *)IO_ADDRESS(mem->start);
 495         i2c_davinci_init(dev);
 496
 497         r = request_irq(dev->irq, i2c_davinci_isr, 0, pdev->name, dev);
 498         if (r) {
 499                 dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
 500                 goto err_unuse_clocks;
 501         }
 502
 503         adap = &dev->adapter;
 504         i2c_set_adapdata(adap, dev);
 505         adap->owner = THIS_MODULE;
 506         adap->class = I2C_CLASS_HWMON;
 507         strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
 508         adap->algo = &i2c_davinci_algo;
 509         adap->dev.parent = &pdev->dev;
 510
 511         /* FIXME */
 512         adap->timeout = 1;
 513         adap->retries = 1;
 514
 515         adap->nr = pdev->id;
 516         r = i2c_add_numbered_adapter(adap);
 517         if (r) {
 518                 dev_err(&pdev->dev, "failure adding adapter\n");
 519                 goto err_free_irq;
 520         }
 521
 522         return 0;
 523
 524 err_free_irq:
 525         free_irq(dev->irq, dev);
 526 err_unuse_clocks:
 527         clk_disable(dev->clk);
 528         clk_put(dev->clk);
 529         dev->clk = NULL;
 530 err_free_mem:
 531         platform_set_drvdata(pdev, NULL);
 532         put_device(&pdev->dev);
 533         kfree(dev);
 534 err_release_region:
 535         release_mem_region(mem->start, (mem->end - mem->start) + 1);
 536
 537         return r;
 538 }
 539
 540 static int davinci_i2c_remove(struct platform_device *pdev)
 541 {
 542         struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
 543         struct resource *mem;
 544
 545         platform_set_drvdata(pdev, NULL);
 546         i2c_del_adapter(&dev->adapter);
 547         put_device(&pdev->dev);
 548
 549         clk_disable(dev->clk);
 550         clk_put(dev->clk);
 551         dev->clk = NULL;
 552
 553         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
 554         free_irq(IRQ_I2C, dev);
 555         kfree(dev);
 556
 557         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 558         release_mem_region(mem->start, (mem->end - mem->start) + 1);
 559         return 0;
 560 }
 561
 562 static struct platform_driver davinci_i2c_driver = {
 563         .probe          = davinci_i2c_probe,
 564         .remove         = davinci_i2c_remove,
 565         .driver         = {
 566                 .name   = "i2c_davinci",
 567                 .owner  = THIS_MODULE,
 568         },
 569 };
 570
 571 /* I2C may be needed to bring up other drivers */
 572 static int __init davinci_i2c_init_driver(void)
 573 {
 574         return platform_driver_register(&davinci_i2c_driver);
 575 }
 576 subsys_initcall(davinci_i2c_init_driver);
 577
 578 static void __exit davinci_i2c_exit_driver(void)
 579 {
 580         platform_driver_unregister(&davinci_i2c_driver);
 581 }
 582 module_exit(davinci_i2c_exit_driver);
 583
 584 MODULE_AUTHOR("Texas Instruments India");
 585 MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
 586 MODULE_LICENSE("GPL");