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  *
  22  */
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/delay.h>
  26 #include <linux/i2c.h>
  27 #include <linux/clk.h>
  28 #include <linux/errno.h>
  29 #include <linux/sched.h>
  30 #include <linux/err.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/io.h>
  34 #include <linux/slab.h>
  35 #include <linux/cpufreq.h>
  36 #include <linux/gpio.h>
  37 #include <linux/of_device.h>
  38 #include <linux/platform_data/i2c-davinci.h>
  39
  40 /* ----- global defines ----------------------------------------------- */
  41
  42 #define DAVINCI_I2C_TIMEOUT     (1*HZ)
  43 #define DAVINCI_I2C_MAX_TRIES   2
  44 #define I2C_DAVINCI_INTR_ALL    (DAVINCI_I2C_IMR_AAS | \
  45                                  DAVINCI_I2C_IMR_SCD | \
  46                                  DAVINCI_I2C_IMR_ARDY | \
  47                                  DAVINCI_I2C_IMR_NACK | \
  48                                  DAVINCI_I2C_IMR_AL)
  49
  50 #define DAVINCI_I2C_OAR_REG     0x00
  51 #define DAVINCI_I2C_IMR_REG     0x04
  52 #define DAVINCI_I2C_STR_REG     0x08
  53 #define DAVINCI_I2C_CLKL_REG    0x0c
  54 #define DAVINCI_I2C_CLKH_REG    0x10
  55 #define DAVINCI_I2C_CNT_REG     0x14
  56 #define DAVINCI_I2C_DRR_REG     0x18
  57 #define DAVINCI_I2C_SAR_REG     0x1c
  58 #define DAVINCI_I2C_DXR_REG     0x20
  59 #define DAVINCI_I2C_MDR_REG     0x24
  60 #define DAVINCI_I2C_IVR_REG     0x28
  61 #define DAVINCI_I2C_EMDR_REG    0x2c
  62 #define DAVINCI_I2C_PSC_REG     0x30
  63
  64 #define DAVINCI_I2C_IVR_AAS     0x07
  65 #define DAVINCI_I2C_IVR_SCD     0x06
  66 #define DAVINCI_I2C_IVR_XRDY    0x05
  67 #define DAVINCI_I2C_IVR_RDR     0x04
  68 #define DAVINCI_I2C_IVR_ARDY    0x03
  69 #define DAVINCI_I2C_IVR_NACK    0x02
  70 #define DAVINCI_I2C_IVR_AL      0x01
  71
  72 #define DAVINCI_I2C_STR_BB      BIT(12)
  73 #define DAVINCI_I2C_STR_RSFULL  BIT(11)
  74 #define DAVINCI_I2C_STR_SCD     BIT(5)
  75 #define DAVINCI_I2C_STR_ARDY    BIT(2)
  76 #define DAVINCI_I2C_STR_NACK    BIT(1)
  77 #define DAVINCI_I2C_STR_AL      BIT(0)
  78
  79 #define DAVINCI_I2C_MDR_NACK    BIT(15)
  80 #define DAVINCI_I2C_MDR_STT     BIT(13)
  81 #define DAVINCI_I2C_MDR_STP     BIT(11)
  82 #define DAVINCI_I2C_MDR_MST     BIT(10)
  83 #define DAVINCI_I2C_MDR_TRX     BIT(9)
  84 #define DAVINCI_I2C_MDR_XA      BIT(8)
  85 #define DAVINCI_I2C_MDR_RM      BIT(7)
  86 #define DAVINCI_I2C_MDR_IRS     BIT(5)
  87
  88 #define DAVINCI_I2C_IMR_AAS     BIT(6)
  89 #define DAVINCI_I2C_IMR_SCD     BIT(5)
  90 #define DAVINCI_I2C_IMR_XRDY    BIT(4)
  91 #define DAVINCI_I2C_IMR_RRDY    BIT(3)
  92 #define DAVINCI_I2C_IMR_ARDY    BIT(2)
  93 #define DAVINCI_I2C_IMR_NACK    BIT(1)
  94 #define DAVINCI_I2C_IMR_AL      BIT(0)
  95
  96 struct davinci_i2c_dev {
  97         struct device           *dev;
  98         void __iomem            *base;
  99         struct completion       cmd_complete;
 100         struct clk              *clk;
 101         int                     cmd_err;
 102         u8                      *buf;
 103         size_t                  buf_len;
 104         int                     irq;
 105         int                     stop;
 106         u8                      terminate;
 107         struct i2c_adapter      adapter;
 108 #ifdef CONFIG_CPU_FREQ
 109         struct completion       xfr_complete;
 110         struct notifier_block   freq_transition;
 111 #endif
 112         struct davinci_i2c_platform_data *pdata;
 113 };
 114
 115 /* default platform data to use if not supplied in the platform_device */
 116 static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
 117         .bus_freq       = 100,
 118         .bus_delay      = 0,
 119 };
 120
 121 static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
 122                                          int reg, u16 val)
 123 {
 124         writew_relaxed(val, i2c_dev->base + reg);
 125 }
 126
 127 static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
 128 {
 129         return readw_relaxed(i2c_dev->base + reg);
 130 }
 131
 132 /* Generate a pulse on the i2c clock pin. */
 133 static void davinci_i2c_clock_pulse(unsigned int scl_pin)
 134 {
 135         u16 i;
 136
 137         if (scl_pin) {
 138                 /* Send high and low on the SCL line */
 139                 for (i = 0; i < 9; i++) {
 140                         gpio_set_value(scl_pin, 0);
 141                         udelay(20);
 142                         gpio_set_value(scl_pin, 1);
 143                         udelay(20);
 144                 }
 145         }
 146 }
 147
 148 /* This routine does i2c bus recovery as specified in the
 149  * i2c protocol Rev. 03 section 3.16 titled "Bus clear"
 150  */
 151 static void davinci_i2c_recover_bus(struct davinci_i2c_dev *dev)
 152 {
 153         u32 flag = 0;
 154         struct davinci_i2c_platform_data *pdata = dev->pdata;
 155
 156         dev_err(dev->dev, "initiating i2c bus recovery\n");
 157         /* Send NACK to the slave */
 158         flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 159         flag |=  DAVINCI_I2C_MDR_NACK;
 160         /* write the data into mode register */
 161         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 162         davinci_i2c_clock_pulse(pdata->scl_pin);
 163         /* Send STOP */
 164         flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 165         flag |= DAVINCI_I2C_MDR_STP;
 166         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 167 }
 168
 169 static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
 170                                                                 int val)
 171 {
 172         u16 w;
 173
 174         w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
 175         if (!val)       /* put I2C into reset */
 176                 w &= ~DAVINCI_I2C_MDR_IRS;
 177         else            /* take I2C out of reset */
 178                 w |= DAVINCI_I2C_MDR_IRS;
 179
 180         davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w);
 181 }
 182
 183 static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
 184 {
 185         struct davinci_i2c_platform_data *pdata = dev->pdata;
 186         u16 psc;
 187         u32 clk;
 188         u32 d;
 189         u32 clkh;
 190         u32 clkl;
 191         u32 input_clock = clk_get_rate(dev->clk);
 192
 193         /* NOTE: I2C Clock divider programming info
 194          * As per I2C specs the following formulas provide prescaler
 195          * and low/high divider values
 196          * input clk --> PSC Div -----------> ICCL/H Div --> output clock
 197          *                       module clk
 198          *
 199          * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
 200          *
 201          * Thus,
 202          * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
 203          *
 204          * where if PSC == 0, d = 7,
 205          *       if PSC == 1, d = 6
 206          *       if PSC > 1 , d = 5
 207          */
 208
 209         /* get minimum of 7 MHz clock, but max of 12 MHz */
 210         psc = (input_clock / 7000000) - 1;
 211         if ((input_clock / (psc + 1)) > 12000000)
 212                 psc++;  /* better to run under spec than over */
 213         d = (psc >= 2) ? 5 : 7 - psc;
 214
 215         clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
 216         clkh = clk >> 1;
 217         clkl = clk - clkh;
 218
 219         davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
 220         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
 221         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
 222
 223         dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
 224 }
 225
 226 /*
 227  * This function configures I2C and brings I2C out of reset.
 228  * This function is called during I2C init function. This function
 229  * also gets called if I2C encounters any errors.
 230  */
 231 static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 232 {
 233         struct davinci_i2c_platform_data *pdata = dev->pdata;
 234
 235         /* put I2C into reset */
 236         davinci_i2c_reset_ctrl(dev, 0);
 237
 238         /* compute clock dividers */
 239         i2c_davinci_calc_clk_dividers(dev);
 240
 241         /* Respond at reserved "SMBus Host" slave address" (and zero);
 242          * we seem to have no option to not respond...
 243          */
 244         davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
 245
 246         dev_dbg(dev->dev, "PSC  = %d\n",
 247                 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
 248         dev_dbg(dev->dev, "CLKL = %d\n",
 249                 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
 250         dev_dbg(dev->dev, "CLKH = %d\n",
 251                 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
 252         dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
 253                 pdata->bus_freq, pdata->bus_delay);
 254
 255
 256         /* Take the I2C module out of reset: */
 257         davinci_i2c_reset_ctrl(dev, 1);
 258
 259         /* Enable interrupts */
 260         davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
 261
 262         return 0;
 263 }
 264
 265 /*
 266  * Waiting for bus not busy
 267  */
 268 static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
 269                                          char allow_sleep)
 270 {
 271         unsigned long timeout;
 272         static u16 to_cnt;
 273
 274         timeout = jiffies + dev->adapter.timeout;
 275         while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
 276                & DAVINCI_I2C_STR_BB) {
 277                 if (to_cnt <= DAVINCI_I2C_MAX_TRIES) {
 278                         if (time_after(jiffies, timeout)) {
 279                                 dev_warn(dev->dev,
 280                                 "timeout waiting for bus ready\n");
 281                                 to_cnt++;
 282                                 return -ETIMEDOUT;
 283                         } else {
 284                                 to_cnt = 0;
 285                                 davinci_i2c_recover_bus(dev);
 286                                 i2c_davinci_init(dev);
 287                         }
 288                 }
 289                 if (allow_sleep)
 290                         schedule_timeout(1);
 291         }
 292
 293         return 0;
 294 }
 295
 296 /*
 297  * Low level master read/write transaction. This function is called
 298  * from i2c_davinci_xfer.
 299  */
 300 static int
 301 i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 302 {
 303         struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 304         struct davinci_i2c_platform_data *pdata = dev->pdata;
 305         u32 flag;
 306         u16 w;
 307         int r;
 308
 309         /* Introduce a delay, required for some boards (e.g Davinci EVM) */
 310         if (pdata->bus_delay)
 311                 udelay(pdata->bus_delay);
 312
 313         /* set the slave address */
 314         davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
 315
 316         dev->buf = msg->buf;
 317         dev->buf_len = msg->len;
 318         dev->stop = stop;
 319
 320         davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
 321
 322         reinit_completion(&dev->cmd_complete);
 323         dev->cmd_err = 0;
 324
 325         /* Take I2C out of reset and configure it as master */
 326         flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST;
 327
 328         /* if the slave address is ten bit address, enable XA bit */
 329         if (msg->flags & I2C_M_TEN)
 330                 flag |= DAVINCI_I2C_MDR_XA;
 331         if (!(msg->flags & I2C_M_RD))
 332                 flag |= DAVINCI_I2C_MDR_TRX;
 333         if (msg->len == 0)
 334                 flag |= DAVINCI_I2C_MDR_RM;
 335
 336         /* Enable receive or transmit interrupts */
 337         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
 338         if (msg->flags & I2C_M_RD)
 339                 w |= DAVINCI_I2C_IMR_RRDY;
 340         else
 341                 w |= DAVINCI_I2C_IMR_XRDY;
 342         davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
 343
 344         dev->terminate = 0;
 345
 346         /*
 347          * Write mode register first as needed for correct behaviour
 348          * on OMAP-L138, but don't set STT yet to avoid a race with XRDY
 349          * occurring before we have loaded DXR
 350          */
 351         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 352
 353         /*
 354          * First byte should be set here, not after interrupt,
 355          * because transmit-data-ready interrupt can come before
 356          * NACK-interrupt during sending of previous message and
 357          * ICDXR may have wrong data
 358          * It also saves us one interrupt, slightly faster
 359          */
 360         if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
 361                 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
 362                 dev->buf_len--;
 363         }
 364
 365         /* Set STT to begin transmit now DXR is loaded */
 366         flag |= DAVINCI_I2C_MDR_STT;
 367         if (stop && msg->len != 0)
 368                 flag |= DAVINCI_I2C_MDR_STP;
 369         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 370
 371         r = wait_for_completion_timeout(&dev->cmd_complete, dev->adapter.timeout);
 372         if (r == 0) {
 373                 dev_err(dev->dev, "controller timed out\n");
 374                 davinci_i2c_recover_bus(dev);
 375                 i2c_davinci_init(dev);
 376                 dev->buf_len = 0;
 377                 return -ETIMEDOUT;
 378         }
 379         if (dev->buf_len) {
 380                 /* This should be 0 if all bytes were transferred
 381                  * or dev->cmd_err denotes an error.
 382                  */
 383                 if (r >= 0) {
 384                         dev_err(dev->dev, "abnormal termination buf_len=%i\n",
 385                                 dev->buf_len);
 386                         r = -EREMOTEIO;
 387                 }
 388                 dev->terminate = 1;
 389                 wmb();
 390                 dev->buf_len = 0;
 391         }
 392         if (r < 0)
 393                 return r;
 394
 395         /* no error */
 396         if (likely(!dev->cmd_err))
 397                 return msg->len;
 398
 399         /* We have an error */
 400         if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
 401                 i2c_davinci_init(dev);
 402                 return -EIO;
 403         }
 404
 405         if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
 406                 if (msg->flags & I2C_M_IGNORE_NAK)
 407                         return msg->len;
 408                 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 409                 w |= DAVINCI_I2C_MDR_STP;
 410                 davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 411                 return -EREMOTEIO;
 412         }
 413         return -EIO;
 414 }
 415
 416 /*
 417  * Prepare controller for a transaction and call i2c_davinci_xfer_msg
 418  */
 419 static int
 420 i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 421 {
 422         struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 423         int i;
 424         int ret;
 425
 426         dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
 427
 428         ret = i2c_davinci_wait_bus_not_busy(dev, 1);
 429         if (ret < 0) {
 430                 dev_warn(dev->dev, "timeout waiting for bus ready\n");
 431                 return ret;
 432         }
 433
 434         for (i = 0; i < num; i++) {
 435                 ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
 436                 dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
 437                         ret);
 438                 if (ret < 0)
 439                         return ret;
 440         }
 441
 442 #ifdef CONFIG_CPU_FREQ
 443         complete(&dev->xfr_complete);
 444 #endif
 445
 446         return num;
 447 }
 448
 449 static u32 i2c_davinci_func(struct i2c_adapter *adap)
 450 {
 451         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 452 }
 453
 454 static void terminate_read(struct davinci_i2c_dev *dev)
 455 {
 456         u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 457         w |= DAVINCI_I2C_MDR_NACK;
 458         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 459
 460         /* Throw away data */
 461         davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG);
 462         if (!dev->terminate)
 463                 dev_err(dev->dev, "RDR IRQ while no data requested\n");
 464 }
 465 static void terminate_write(struct davinci_i2c_dev *dev)
 466 {
 467         u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 468         w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
 469         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 470
 471         if (!dev->terminate)
 472                 dev_dbg(dev->dev, "TDR IRQ while no data to send\n");
 473 }
 474
 475 /*
 476  * Interrupt service routine. This gets called whenever an I2C interrupt
 477  * occurs.
 478  */
 479 static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
 480 {
 481         struct davinci_i2c_dev *dev = dev_id;
 482         u32 stat;
 483         int count = 0;
 484         u16 w;
 485
 486         while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
 487                 dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
 488                 if (count++ == 100) {
 489                         dev_warn(dev->dev, "Too much work in one IRQ\n");
 490                         break;
 491                 }
 492
 493                 switch (stat) {
 494                 case DAVINCI_I2C_IVR_AL:
 495                         /* Arbitration lost, must retry */
 496                         dev->cmd_err |= DAVINCI_I2C_STR_AL;
 497                         dev->buf_len = 0;
 498                         complete(&dev->cmd_complete);
 499                         break;
 500
 501                 case DAVINCI_I2C_IVR_NACK:
 502                         dev->cmd_err |= DAVINCI_I2C_STR_NACK;
 503                         dev->buf_len = 0;
 504                         complete(&dev->cmd_complete);
 505                         break;
 506
 507                 case DAVINCI_I2C_IVR_ARDY:
 508                         davinci_i2c_write_reg(dev,
 509                                 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
 510                         if (((dev->buf_len == 0) && (dev->stop != 0)) ||
 511                             (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
 512                                 w = davinci_i2c_read_reg(dev,
 513                                                          DAVINCI_I2C_MDR_REG);
 514                                 w |= DAVINCI_I2C_MDR_STP;
 515                                 davinci_i2c_write_reg(dev,
 516                                                       DAVINCI_I2C_MDR_REG, w);
 517                         }
 518                         complete(&dev->cmd_complete);
 519                         break;
 520
 521                 case DAVINCI_I2C_IVR_RDR:
 522                         if (dev->buf_len) {
 523                                 *dev->buf++ =
 524                                     davinci_i2c_read_reg(dev,
 525                                                          DAVINCI_I2C_DRR_REG);
 526                                 dev->buf_len--;
 527                                 if (dev->buf_len)
 528                                         continue;
 529
 530                                 davinci_i2c_write_reg(dev,
 531                                         DAVINCI_I2C_STR_REG,
 532                                         DAVINCI_I2C_IMR_RRDY);
 533                         } else {
 534                                 /* signal can terminate transfer */
 535                                 terminate_read(dev);
 536                         }
 537                         break;
 538
 539                 case DAVINCI_I2C_IVR_XRDY:
 540                         if (dev->buf_len) {
 541                                 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
 542                                                       *dev->buf++);
 543                                 dev->buf_len--;
 544                                 if (dev->buf_len)
 545                                         continue;
 546
 547                                 w = davinci_i2c_read_reg(dev,
 548                                                          DAVINCI_I2C_IMR_REG);
 549                                 w &= ~DAVINCI_I2C_IMR_XRDY;
 550                                 davinci_i2c_write_reg(dev,
 551                                                       DAVINCI_I2C_IMR_REG,
 552                                                       w);
 553                         } else {
 554                                 /* signal can terminate transfer */
 555                                 terminate_write(dev);
 556                         }
 557                         break;
 558
 559                 case DAVINCI_I2C_IVR_SCD:
 560                         davinci_i2c_write_reg(dev,
 561                                 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
 562                         complete(&dev->cmd_complete);
 563                         break;
 564
 565                 case DAVINCI_I2C_IVR_AAS:
 566                         dev_dbg(dev->dev, "Address as slave interrupt\n");
 567                         break;
 568
 569                 default:
 570                         dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat);
 571                         break;
 572                 }
 573         }
 574
 575         return count ? IRQ_HANDLED : IRQ_NONE;
 576 }
 577
 578 #ifdef CONFIG_CPU_FREQ
 579 static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
 580                                      unsigned long val, void *data)
 581 {
 582         struct davinci_i2c_dev *dev;
 583
 584         dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
 585         if (val == CPUFREQ_PRECHANGE) {
 586                 wait_for_completion(&dev->xfr_complete);
 587                 davinci_i2c_reset_ctrl(dev, 0);
 588         } else if (val == CPUFREQ_POSTCHANGE) {
 589                 i2c_davinci_calc_clk_dividers(dev);
 590                 davinci_i2c_reset_ctrl(dev, 1);
 591         }
 592
 593         return 0;
 594 }
 595
 596 static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
 597 {
 598         dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
 599
 600         return cpufreq_register_notifier(&dev->freq_transition,
 601                                          CPUFREQ_TRANSITION_NOTIFIER);
 602 }
 603
 604 static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
 605 {
 606         cpufreq_unregister_notifier(&dev->freq_transition,
 607                                     CPUFREQ_TRANSITION_NOTIFIER);
 608 }
 609 #else
 610 static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
 611 {
 612         return 0;
 613 }
 614
 615 static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
 616 {
 617 }
 618 #endif
 619
 620 static struct i2c_algorithm i2c_davinci_algo = {
 621         .master_xfer    = i2c_davinci_xfer,
 622         .functionality  = i2c_davinci_func,
 623 };
 624
 625 static const struct of_device_id davinci_i2c_of_match[] = {
 626         {.compatible = "ti,davinci-i2c", },
 627         {},
 628 };
 629 MODULE_DEVICE_TABLE(of, davinci_i2c_of_match);
 630
 631 static int davinci_i2c_probe(struct platform_device *pdev)
 632 {
 633         struct davinci_i2c_dev *dev;
 634         struct i2c_adapter *adap;
 635         struct resource *mem;
 636         int r, irq;
 637
 638         irq = platform_get_irq(pdev, 0);
 639         if (irq <= 0) {
 640                 if (!irq)
 641                         irq = -ENXIO;
 642                 if (irq != -EPROBE_DEFER)
 643                         dev_err(&pdev->dev,
 644                                 "can't get irq resource ret=%d\n", irq);
 645                 return irq;
 646         }
 647
 648         dev = devm_kzalloc(&pdev->dev, sizeof(struct davinci_i2c_dev),
 649                         GFP_KERNEL);
 650         if (!dev) {
 651                 dev_err(&pdev->dev, "Memory allocation failed\n");
 652                 return -ENOMEM;
 653         }
 654
 655         init_completion(&dev->cmd_complete);
 656 #ifdef CONFIG_CPU_FREQ
 657         init_completion(&dev->xfr_complete);
 658 #endif
 659         dev->dev = &pdev->dev;
 660         dev->irq = irq;
 661         dev->pdata = dev_get_platdata(&pdev->dev);
 662         platform_set_drvdata(pdev, dev);
 663
 664         if (!dev->pdata && pdev->dev.of_node) {
 665                 u32 prop;
 666
 667                 dev->pdata = devm_kzalloc(&pdev->dev,
 668                         sizeof(struct davinci_i2c_platform_data), GFP_KERNEL);
 669                 if (!dev->pdata)
 670                         return -ENOMEM;
 671
 672                 memcpy(dev->pdata, &davinci_i2c_platform_data_default,
 673                         sizeof(struct davinci_i2c_platform_data));
 674                 if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency",
 675                         &prop))
 676                         dev->pdata->bus_freq = prop / 1000;
 677         } else if (!dev->pdata) {
 678                 dev->pdata = &davinci_i2c_platform_data_default;
 679         }
 680
 681         dev->clk = devm_clk_get(&pdev->dev, NULL);
 682         if (IS_ERR(dev->clk))
 683                 return -ENODEV;
 684         clk_prepare_enable(dev->clk);
 685
 686         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 687         dev->base = devm_ioremap_resource(&pdev->dev, mem);
 688         if (IS_ERR(dev->base)) {
 689                 r = PTR_ERR(dev->base);
 690                 goto err_unuse_clocks;
 691         }
 692
 693         i2c_davinci_init(dev);
 694
 695         r = devm_request_irq(&pdev->dev, dev->irq, i2c_davinci_isr, 0,
 696                         pdev->name, dev);
 697         if (r) {
 698                 dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
 699                 goto err_unuse_clocks;
 700         }
 701
 702         r = i2c_davinci_cpufreq_register(dev);
 703         if (r) {
 704                 dev_err(&pdev->dev, "failed to register cpufreq\n");
 705                 goto err_unuse_clocks;
 706         }
 707
 708         adap = &dev->adapter;
 709         i2c_set_adapdata(adap, dev);
 710         adap->owner = THIS_MODULE;
 711         adap->class = I2C_CLASS_DEPRECATED;
 712         strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
 713         adap->algo = &i2c_davinci_algo;
 714         adap->dev.parent = &pdev->dev;
 715         adap->timeout = DAVINCI_I2C_TIMEOUT;
 716         adap->dev.of_node = pdev->dev.of_node;
 717
 718         adap->nr = pdev->id;
 719         r = i2c_add_numbered_adapter(adap);
 720         if (r) {
 721                 dev_err(&pdev->dev, "failure adding adapter\n");
 722                 goto err_unuse_clocks;
 723         }
 724
 725         return 0;
 726
 727 err_unuse_clocks:
 728         clk_disable_unprepare(dev->clk);
 729         dev->clk = NULL;
 730         return r;
 731 }
 732
 733 static int davinci_i2c_remove(struct platform_device *pdev)
 734 {
 735         struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
 736
 737         i2c_davinci_cpufreq_deregister(dev);
 738
 739         i2c_del_adapter(&dev->adapter);
 740
 741         clk_disable_unprepare(dev->clk);
 742         dev->clk = NULL;
 743
 744         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
 745
 746         return 0;
 747 }
 748
 749 #ifdef CONFIG_PM
 750 static int davinci_i2c_suspend(struct device *dev)
 751 {
 752         struct platform_device *pdev = to_platform_device(dev);
 753         struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 754
 755         /* put I2C into reset */
 756         davinci_i2c_reset_ctrl(i2c_dev, 0);
 757         clk_disable_unprepare(i2c_dev->clk);
 758
 759         return 0;
 760 }
 761
 762 static int davinci_i2c_resume(struct device *dev)
 763 {
 764         struct platform_device *pdev = to_platform_device(dev);
 765         struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 766
 767         clk_prepare_enable(i2c_dev->clk);
 768         /* take I2C out of reset */
 769         davinci_i2c_reset_ctrl(i2c_dev, 1);
 770
 771         return 0;
 772 }
 773
 774 static const struct dev_pm_ops davinci_i2c_pm = {
 775         .suspend        = davinci_i2c_suspend,
 776         .resume         = davinci_i2c_resume,
 777 };
 778
 779 #define davinci_i2c_pm_ops (&davinci_i2c_pm)
 780 #else
 781 #define davinci_i2c_pm_ops NULL
 782 #endif
 783
 784 /* work with hotplug and coldplug */
 785 MODULE_ALIAS("platform:i2c_davinci");
 786
 787 static struct platform_driver davinci_i2c_driver = {
 788         .probe          = davinci_i2c_probe,
 789         .remove         = davinci_i2c_remove,
 790         .driver         = {
 791                 .name   = "i2c_davinci",
 792                 .pm     = davinci_i2c_pm_ops,
 793                 .of_match_table = davinci_i2c_of_match,
 794         },
 795 };
 796
 797 /* I2C may be needed to bring up other drivers */
 798 static int __init davinci_i2c_init_driver(void)
 799 {
 800         return platform_driver_register(&davinci_i2c_driver);
 801 }
 802 subsys_initcall(davinci_i2c_init_driver);
 803
 804 static void __exit davinci_i2c_exit_driver(void)
 805 {
 806         platform_driver_unregister(&davinci_i2c_driver);
 807 }
 808 module_exit(davinci_i2c_exit_driver);
 809
 810 MODULE_AUTHOR("Texas Instruments India");
 811 MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
 812 MODULE_LICENSE("GPL");