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 #include <linux/slab.h>
  39 #include <linux/cpufreq.h>
  40 #include <linux/gpio.h>
  41 #include <linux/of_device.h>
  42 #include <linux/platform_data/i2c-davinci.h>
  43
  44 /* ----- global defines ----------------------------------------------- */
  45
  46 #define DAVINCI_I2C_TIMEOUT     (1*HZ)
  47 #define DAVINCI_I2C_MAX_TRIES   2
  48 #define I2C_DAVINCI_INTR_ALL    (DAVINCI_I2C_IMR_AAS | \
  49                                  DAVINCI_I2C_IMR_SCD | \
  50                                  DAVINCI_I2C_IMR_ARDY | \
  51                                  DAVINCI_I2C_IMR_NACK | \
  52                                  DAVINCI_I2C_IMR_AL)
  53
  54 #define DAVINCI_I2C_OAR_REG     0x00
  55 #define DAVINCI_I2C_IMR_REG     0x04
  56 #define DAVINCI_I2C_STR_REG     0x08
  57 #define DAVINCI_I2C_CLKL_REG    0x0c
  58 #define DAVINCI_I2C_CLKH_REG    0x10
  59 #define DAVINCI_I2C_CNT_REG     0x14
  60 #define DAVINCI_I2C_DRR_REG     0x18
  61 #define DAVINCI_I2C_SAR_REG     0x1c
  62 #define DAVINCI_I2C_DXR_REG     0x20
  63 #define DAVINCI_I2C_MDR_REG     0x24
  64 #define DAVINCI_I2C_IVR_REG     0x28
  65 #define DAVINCI_I2C_EMDR_REG    0x2c
  66 #define DAVINCI_I2C_PSC_REG     0x30
  67
  68 #define DAVINCI_I2C_IVR_AAS     0x07
  69 #define DAVINCI_I2C_IVR_SCD     0x06
  70 #define DAVINCI_I2C_IVR_XRDY    0x05
  71 #define DAVINCI_I2C_IVR_RDR     0x04
  72 #define DAVINCI_I2C_IVR_ARDY    0x03
  73 #define DAVINCI_I2C_IVR_NACK    0x02
  74 #define DAVINCI_I2C_IVR_AL      0x01
  75
  76 #define DAVINCI_I2C_STR_BB      BIT(12)
  77 #define DAVINCI_I2C_STR_RSFULL  BIT(11)
  78 #define DAVINCI_I2C_STR_SCD     BIT(5)
  79 #define DAVINCI_I2C_STR_ARDY    BIT(2)
  80 #define DAVINCI_I2C_STR_NACK    BIT(1)
  81 #define DAVINCI_I2C_STR_AL      BIT(0)
  82
  83 #define DAVINCI_I2C_MDR_NACK    BIT(15)
  84 #define DAVINCI_I2C_MDR_STT     BIT(13)
  85 #define DAVINCI_I2C_MDR_STP     BIT(11)
  86 #define DAVINCI_I2C_MDR_MST     BIT(10)
  87 #define DAVINCI_I2C_MDR_TRX     BIT(9)
  88 #define DAVINCI_I2C_MDR_XA      BIT(8)
  89 #define DAVINCI_I2C_MDR_RM      BIT(7)
  90 #define DAVINCI_I2C_MDR_IRS     BIT(5)
  91
  92 #define DAVINCI_I2C_IMR_AAS     BIT(6)
  93 #define DAVINCI_I2C_IMR_SCD     BIT(5)
  94 #define DAVINCI_I2C_IMR_XRDY    BIT(4)
  95 #define DAVINCI_I2C_IMR_RRDY    BIT(3)
  96 #define DAVINCI_I2C_IMR_ARDY    BIT(2)
  97 #define DAVINCI_I2C_IMR_NACK    BIT(1)
  98 #define DAVINCI_I2C_IMR_AL      BIT(0)
  99
 100 struct davinci_i2c_dev {
 101         struct device           *dev;
 102         void __iomem            *base;
 103         struct completion       cmd_complete;
 104         struct clk              *clk;
 105         int                     cmd_err;
 106         u8                      *buf;
 107         size_t                  buf_len;
 108         int                     irq;
 109         int                     stop;
 110         u8                      terminate;
 111         struct i2c_adapter      adapter;
 112 #ifdef CONFIG_CPU_FREQ
 113         struct completion       xfr_complete;
 114         struct notifier_block   freq_transition;
 115 #endif
 116         struct davinci_i2c_platform_data *pdata;
 117 };
 118
 119 /* default platform data to use if not supplied in the platform_device */
 120 static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
 121         .bus_freq       = 100,
 122         .bus_delay      = 0,
 123 };
 124
 125 static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
 126                                          int reg, u16 val)
 127 {
 128         writew_relaxed(val, i2c_dev->base + reg);
 129 }
 130
 131 static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
 132 {
 133         return readw_relaxed(i2c_dev->base + reg);
 134 }
 135
 136 /* Generate a pulse on the i2c clock pin. */
 137 static void davinci_i2c_clock_pulse(unsigned int scl_pin)
 138 {
 139         u16 i;
 140
 141         if (scl_pin) {
 142                 /* Send high and low on the SCL line */
 143                 for (i = 0; i < 9; i++) {
 144                         gpio_set_value(scl_pin, 0);
 145                         udelay(20);
 146                         gpio_set_value(scl_pin, 1);
 147                         udelay(20);
 148                 }
 149         }
 150 }
 151
 152 /* This routine does i2c bus recovery as specified in the
 153  * i2c protocol Rev. 03 section 3.16 titled "Bus clear"
 154  */
 155 static void davinci_i2c_recover_bus(struct davinci_i2c_dev *dev)
 156 {
 157         u32 flag = 0;
 158         struct davinci_i2c_platform_data *pdata = dev->pdata;
 159
 160         dev_err(dev->dev, "initiating i2c bus recovery\n");
 161         /* Send NACK to the slave */
 162         flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 163         flag |=  DAVINCI_I2C_MDR_NACK;
 164         /* write the data into mode register */
 165         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 166         davinci_i2c_clock_pulse(pdata->scl_pin);
 167         /* Send STOP */
 168         flag = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 169         flag |= DAVINCI_I2C_MDR_STP;
 170         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 171 }
 172
 173 static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
 174                                                                 int val)
 175 {
 176         u16 w;
 177
 178         w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
 179         if (!val)       /* put I2C into reset */
 180                 w &= ~DAVINCI_I2C_MDR_IRS;
 181         else            /* take I2C out of reset */
 182                 w |= DAVINCI_I2C_MDR_IRS;
 183
 184         davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w);
 185 }
 186
 187 static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
 188 {
 189         struct davinci_i2c_platform_data *pdata = dev->pdata;
 190         u16 psc;
 191         u32 clk;
 192         u32 d;
 193         u32 clkh;
 194         u32 clkl;
 195         u32 input_clock = clk_get_rate(dev->clk);
 196
 197         /* NOTE: I2C Clock divider programming info
 198          * As per I2C specs the following formulas provide prescaler
 199          * and low/high divider values
 200          * input clk --> PSC Div -----------> ICCL/H Div --> output clock
 201          *                       module clk
 202          *
 203          * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
 204          *
 205          * Thus,
 206          * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
 207          *
 208          * where if PSC == 0, d = 7,
 209          *       if PSC == 1, d = 6
 210          *       if PSC > 1 , d = 5
 211          */
 212
 213         /* get minimum of 7 MHz clock, but max of 12 MHz */
 214         psc = (input_clock / 7000000) - 1;
 215         if ((input_clock / (psc + 1)) > 12000000)
 216                 psc++;  /* better to run under spec than over */
 217         d = (psc >= 2) ? 5 : 7 - psc;
 218
 219         clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
 220         clkh = clk >> 1;
 221         clkl = clk - clkh;
 222
 223         davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
 224         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
 225         davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
 226
 227         dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
 228 }
 229
 230 /*
 231  * This function configures I2C and brings I2C out of reset.
 232  * This function is called during I2C init function. This function
 233  * also gets called if I2C encounters any errors.
 234  */
 235 static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 236 {
 237         struct davinci_i2c_platform_data *pdata = dev->pdata;
 238
 239         /* put I2C into reset */
 240         davinci_i2c_reset_ctrl(dev, 0);
 241
 242         /* compute clock dividers */
 243         i2c_davinci_calc_clk_dividers(dev);
 244
 245         /* Respond at reserved "SMBus Host" slave address" (and zero);
 246          * we seem to have no option to not respond...
 247          */
 248         davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
 249
 250         dev_dbg(dev->dev, "PSC  = %d\n",
 251                 davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
 252         dev_dbg(dev->dev, "CLKL = %d\n",
 253                 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
 254         dev_dbg(dev->dev, "CLKH = %d\n",
 255                 davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
 256         dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
 257                 pdata->bus_freq, pdata->bus_delay);
 258
 259
 260         /* Take the I2C module out of reset: */
 261         davinci_i2c_reset_ctrl(dev, 1);
 262
 263         /* Enable interrupts */
 264         davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
 265
 266         return 0;
 267 }
 268
 269 /*
 270  * Waiting for bus not busy
 271  */
 272 static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
 273                                          char allow_sleep)
 274 {
 275         unsigned long timeout;
 276         static u16 to_cnt;
 277
 278         timeout = jiffies + dev->adapter.timeout;
 279         while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
 280                & DAVINCI_I2C_STR_BB) {
 281                 if (to_cnt <= DAVINCI_I2C_MAX_TRIES) {
 282                         if (time_after(jiffies, timeout)) {
 283                                 dev_warn(dev->dev,
 284                                 "timeout waiting for bus ready\n");
 285                                 to_cnt++;
 286                                 return -ETIMEDOUT;
 287                         } else {
 288                                 to_cnt = 0;
 289                                 davinci_i2c_recover_bus(dev);
 290                                 i2c_davinci_init(dev);
 291                         }
 292                 }
 293                 if (allow_sleep)
 294                         schedule_timeout(1);
 295         }
 296
 297         return 0;
 298 }
 299
 300 /*
 301  * Low level master read/write transaction. This function is called
 302  * from i2c_davinci_xfer.
 303  */
 304 static int
 305 i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 306 {
 307         struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 308         struct davinci_i2c_platform_data *pdata = dev->pdata;
 309         u32 flag;
 310         u16 w;
 311         int r;
 312
 313         /* Introduce a delay, required for some boards (e.g Davinci EVM) */
 314         if (pdata->bus_delay)
 315                 udelay(pdata->bus_delay);
 316
 317         /* set the slave address */
 318         davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
 319
 320         dev->buf = msg->buf;
 321         dev->buf_len = msg->len;
 322         dev->stop = stop;
 323
 324         davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
 325
 326         reinit_completion(&dev->cmd_complete);
 327         dev->cmd_err = 0;
 328
 329         /* Take I2C out of reset and configure it as master */
 330         flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST;
 331
 332         /* if the slave address is ten bit address, enable XA bit */
 333         if (msg->flags & I2C_M_TEN)
 334                 flag |= DAVINCI_I2C_MDR_XA;
 335         if (!(msg->flags & I2C_M_RD))
 336                 flag |= DAVINCI_I2C_MDR_TRX;
 337         if (msg->len == 0)
 338                 flag |= DAVINCI_I2C_MDR_RM;
 339
 340         /* Enable receive or transmit interrupts */
 341         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
 342         if (msg->flags & I2C_M_RD)
 343                 w |= DAVINCI_I2C_IMR_RRDY;
 344         else
 345                 w |= DAVINCI_I2C_IMR_XRDY;
 346         davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
 347
 348         dev->terminate = 0;
 349
 350         /*
 351          * Write mode register first as needed for correct behaviour
 352          * on OMAP-L138, but don't set STT yet to avoid a race with XRDY
 353          * occurring before we have loaded DXR
 354          */
 355         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 356
 357         /*
 358          * First byte should be set here, not after interrupt,
 359          * because transmit-data-ready interrupt can come before
 360          * NACK-interrupt during sending of previous message and
 361          * ICDXR may have wrong data
 362          * It also saves us one interrupt, slightly faster
 363          */
 364         if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
 365                 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
 366                 dev->buf_len--;
 367         }
 368
 369         /* Set STT to begin transmit now DXR is loaded */
 370         flag |= DAVINCI_I2C_MDR_STT;
 371         if (stop && msg->len != 0)
 372                 flag |= DAVINCI_I2C_MDR_STP;
 373         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 374
 375         r = wait_for_completion_interruptible_timeout(&dev->cmd_complete,
 376                                                       dev->adapter.timeout);
 377         if (r == 0) {
 378                 dev_err(dev->dev, "controller timed out\n");
 379                 davinci_i2c_recover_bus(dev);
 380                 i2c_davinci_init(dev);
 381                 dev->buf_len = 0;
 382                 return -ETIMEDOUT;
 383         }
 384         if (dev->buf_len) {
 385                 /* This should be 0 if all bytes were transferred
 386                  * or dev->cmd_err denotes an error.
 387                  * A signal may have aborted the transfer.
 388                  */
 389                 if (r >= 0) {
 390                         dev_err(dev->dev, "abnormal termination buf_len=%i\n",
 391                                 dev->buf_len);
 392                         r = -EREMOTEIO;
 393                 }
 394                 dev->terminate = 1;
 395                 wmb();
 396                 dev->buf_len = 0;
 397         }
 398         if (r < 0)
 399                 return r;
 400
 401         /* no error */
 402         if (likely(!dev->cmd_err))
 403                 return msg->len;
 404
 405         /* We have an error */
 406         if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
 407                 i2c_davinci_init(dev);
 408                 return -EIO;
 409         }
 410
 411         if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
 412                 if (msg->flags & I2C_M_IGNORE_NAK)
 413                         return msg->len;
 414                 if (stop) {
 415                         w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 416                         w |= DAVINCI_I2C_MDR_STP;
 417                         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 418                 }
 419                 return -EREMOTEIO;
 420         }
 421         return -EIO;
 422 }
 423
 424 /*
 425  * Prepare controller for a transaction and call i2c_davinci_xfer_msg
 426  */
 427 static int
 428 i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 429 {
 430         struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 431         int i;
 432         int ret;
 433
 434         dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
 435
 436         ret = i2c_davinci_wait_bus_not_busy(dev, 1);
 437         if (ret < 0) {
 438                 dev_warn(dev->dev, "timeout waiting for bus ready\n");
 439                 return ret;
 440         }
 441
 442         for (i = 0; i < num; i++) {
 443                 ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
 444                 dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
 445                         ret);
 446                 if (ret < 0)
 447                         return ret;
 448         }
 449
 450 #ifdef CONFIG_CPU_FREQ
 451         complete(&dev->xfr_complete);
 452 #endif
 453
 454         return num;
 455 }
 456
 457 static u32 i2c_davinci_func(struct i2c_adapter *adap)
 458 {
 459         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 460 }
 461
 462 static void terminate_read(struct davinci_i2c_dev *dev)
 463 {
 464         u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 465         w |= DAVINCI_I2C_MDR_NACK;
 466         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 467
 468         /* Throw away data */
 469         davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG);
 470         if (!dev->terminate)
 471                 dev_err(dev->dev, "RDR IRQ while no data requested\n");
 472 }
 473 static void terminate_write(struct davinci_i2c_dev *dev)
 474 {
 475         u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 476         w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
 477         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 478
 479         if (!dev->terminate)
 480                 dev_dbg(dev->dev, "TDR IRQ while no data to send\n");
 481 }
 482
 483 /*
 484  * Interrupt service routine. This gets called whenever an I2C interrupt
 485  * occurs.
 486  */
 487 static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
 488 {
 489         struct davinci_i2c_dev *dev = dev_id;
 490         u32 stat;
 491         int count = 0;
 492         u16 w;
 493
 494         while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
 495                 dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
 496                 if (count++ == 100) {
 497                         dev_warn(dev->dev, "Too much work in one IRQ\n");
 498                         break;
 499                 }
 500
 501                 switch (stat) {
 502                 case DAVINCI_I2C_IVR_AL:
 503                         /* Arbitration lost, must retry */
 504                         dev->cmd_err |= DAVINCI_I2C_STR_AL;
 505                         dev->buf_len = 0;
 506                         complete(&dev->cmd_complete);
 507                         break;
 508
 509                 case DAVINCI_I2C_IVR_NACK:
 510                         dev->cmd_err |= DAVINCI_I2C_STR_NACK;
 511                         dev->buf_len = 0;
 512                         complete(&dev->cmd_complete);
 513                         break;
 514
 515                 case DAVINCI_I2C_IVR_ARDY:
 516                         davinci_i2c_write_reg(dev,
 517                                 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
 518                         if (((dev->buf_len == 0) && (dev->stop != 0)) ||
 519                             (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
 520                                 w = davinci_i2c_read_reg(dev,
 521                                                          DAVINCI_I2C_MDR_REG);
 522                                 w |= DAVINCI_I2C_MDR_STP;
 523                                 davinci_i2c_write_reg(dev,
 524                                                       DAVINCI_I2C_MDR_REG, w);
 525                         }
 526                         complete(&dev->cmd_complete);
 527                         break;
 528
 529                 case DAVINCI_I2C_IVR_RDR:
 530                         if (dev->buf_len) {
 531                                 *dev->buf++ =
 532                                     davinci_i2c_read_reg(dev,
 533                                                          DAVINCI_I2C_DRR_REG);
 534                                 dev->buf_len--;
 535                                 if (dev->buf_len)
 536                                         continue;
 537
 538                                 davinci_i2c_write_reg(dev,
 539                                         DAVINCI_I2C_STR_REG,
 540                                         DAVINCI_I2C_IMR_RRDY);
 541                         } else {
 542                                 /* signal can terminate transfer */
 543                                 terminate_read(dev);
 544                         }
 545                         break;
 546
 547                 case DAVINCI_I2C_IVR_XRDY:
 548                         if (dev->buf_len) {
 549                                 davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
 550                                                       *dev->buf++);
 551                                 dev->buf_len--;
 552                                 if (dev->buf_len)
 553                                         continue;
 554
 555                                 w = davinci_i2c_read_reg(dev,
 556                                                          DAVINCI_I2C_IMR_REG);
 557                                 w &= ~DAVINCI_I2C_IMR_XRDY;
 558                                 davinci_i2c_write_reg(dev,
 559                                                       DAVINCI_I2C_IMR_REG,
 560                                                       w);
 561                         } else {
 562                                 /* signal can terminate transfer */
 563                                 terminate_write(dev);
 564                         }
 565                         break;
 566
 567                 case DAVINCI_I2C_IVR_SCD:
 568                         davinci_i2c_write_reg(dev,
 569                                 DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
 570                         complete(&dev->cmd_complete);
 571                         break;
 572
 573                 case DAVINCI_I2C_IVR_AAS:
 574                         dev_dbg(dev->dev, "Address as slave interrupt\n");
 575                         break;
 576
 577                 default:
 578                         dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat);
 579                         break;
 580                 }
 581         }
 582
 583         return count ? IRQ_HANDLED : IRQ_NONE;
 584 }
 585
 586 #ifdef CONFIG_CPU_FREQ
 587 static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
 588                                      unsigned long val, void *data)
 589 {
 590         struct davinci_i2c_dev *dev;
 591
 592         dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
 593         if (val == CPUFREQ_PRECHANGE) {
 594                 wait_for_completion(&dev->xfr_complete);
 595                 davinci_i2c_reset_ctrl(dev, 0);
 596         } else if (val == CPUFREQ_POSTCHANGE) {
 597                 i2c_davinci_calc_clk_dividers(dev);
 598                 davinci_i2c_reset_ctrl(dev, 1);
 599         }
 600
 601         return 0;
 602 }
 603
 604 static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
 605 {
 606         dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
 607
 608         return cpufreq_register_notifier(&dev->freq_transition,
 609                                          CPUFREQ_TRANSITION_NOTIFIER);
 610 }
 611
 612 static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
 613 {
 614         cpufreq_unregister_notifier(&dev->freq_transition,
 615                                     CPUFREQ_TRANSITION_NOTIFIER);
 616 }
 617 #else
 618 static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
 619 {
 620         return 0;
 621 }
 622
 623 static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
 624 {
 625 }
 626 #endif
 627
 628 static struct i2c_algorithm i2c_davinci_algo = {
 629         .master_xfer    = i2c_davinci_xfer,
 630         .functionality  = i2c_davinci_func,
 631 };
 632
 633 static const struct of_device_id davinci_i2c_of_match[] = {
 634         {.compatible = "ti,davinci-i2c", },
 635         {},
 636 };
 637 MODULE_DEVICE_TABLE(of, davinci_i2c_of_match);
 638
 639 static int davinci_i2c_probe(struct platform_device *pdev)
 640 {
 641         struct davinci_i2c_dev *dev;
 642         struct i2c_adapter *adap;
 643         struct resource *mem, *irq;
 644         int r;
 645
 646         irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 647         if (!irq) {
 648                 dev_err(&pdev->dev, "no irq resource?\n");
 649                 return -ENODEV;
 650         }
 651
 652         dev = devm_kzalloc(&pdev->dev, sizeof(struct davinci_i2c_dev),
 653                         GFP_KERNEL);
 654         if (!dev) {
 655                 dev_err(&pdev->dev, "Memory allocation failed\n");
 656                 return -ENOMEM;
 657         }
 658
 659         init_completion(&dev->cmd_complete);
 660 #ifdef CONFIG_CPU_FREQ
 661         init_completion(&dev->xfr_complete);
 662 #endif
 663         dev->dev = &pdev->dev;
 664         dev->irq = irq->start;
 665         dev->pdata = dev_get_platdata(&pdev->dev);
 666         platform_set_drvdata(pdev, dev);
 667
 668         if (!dev->pdata && pdev->dev.of_node) {
 669                 u32 prop;
 670
 671                 dev->pdata = devm_kzalloc(&pdev->dev,
 672                         sizeof(struct davinci_i2c_platform_data), GFP_KERNEL);
 673                 if (!dev->pdata)
 674                         return -ENOMEM;
 675
 676                 memcpy(dev->pdata, &davinci_i2c_platform_data_default,
 677                         sizeof(struct davinci_i2c_platform_data));
 678                 if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency",
 679                         &prop))
 680                         dev->pdata->bus_freq = prop / 1000;
 681         } else if (!dev->pdata) {
 682                 dev->pdata = &davinci_i2c_platform_data_default;
 683         }
 684
 685         dev->clk = devm_clk_get(&pdev->dev, NULL);
 686         if (IS_ERR(dev->clk))
 687                 return -ENODEV;
 688         clk_prepare_enable(dev->clk);
 689
 690         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 691         dev->base = devm_ioremap_resource(&pdev->dev, mem);
 692         if (IS_ERR(dev->base)) {
 693                 r = PTR_ERR(dev->base);
 694                 goto err_unuse_clocks;
 695         }
 696
 697         i2c_davinci_init(dev);
 698
 699         r = devm_request_irq(&pdev->dev, dev->irq, i2c_davinci_isr, 0,
 700                         pdev->name, dev);
 701         if (r) {
 702                 dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
 703                 goto err_unuse_clocks;
 704         }
 705
 706         r = i2c_davinci_cpufreq_register(dev);
 707         if (r) {
 708                 dev_err(&pdev->dev, "failed to register cpufreq\n");
 709                 goto err_unuse_clocks;
 710         }
 711
 712         adap = &dev->adapter;
 713         i2c_set_adapdata(adap, dev);
 714         adap->owner = THIS_MODULE;
 715         adap->class = I2C_CLASS_HWMON;
 716         strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
 717         adap->algo = &i2c_davinci_algo;
 718         adap->dev.parent = &pdev->dev;
 719         adap->timeout = DAVINCI_I2C_TIMEOUT;
 720         adap->dev.of_node = pdev->dev.of_node;
 721
 722         adap->nr = pdev->id;
 723         r = i2c_add_numbered_adapter(adap);
 724         if (r) {
 725                 dev_err(&pdev->dev, "failure adding adapter\n");
 726                 goto err_unuse_clocks;
 727         }
 728
 729         return 0;
 730
 731 err_unuse_clocks:
 732         clk_disable_unprepare(dev->clk);
 733         dev->clk = NULL;
 734         return r;
 735 }
 736
 737 static int davinci_i2c_remove(struct platform_device *pdev)
 738 {
 739         struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
 740
 741         i2c_davinci_cpufreq_deregister(dev);
 742
 743         i2c_del_adapter(&dev->adapter);
 744
 745         clk_disable_unprepare(dev->clk);
 746         dev->clk = NULL;
 747
 748         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
 749
 750         return 0;
 751 }
 752
 753 #ifdef CONFIG_PM
 754 static int davinci_i2c_suspend(struct device *dev)
 755 {
 756         struct platform_device *pdev = to_platform_device(dev);
 757         struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 758
 759         /* put I2C into reset */
 760         davinci_i2c_reset_ctrl(i2c_dev, 0);
 761         clk_disable_unprepare(i2c_dev->clk);
 762
 763         return 0;
 764 }
 765
 766 static int davinci_i2c_resume(struct device *dev)
 767 {
 768         struct platform_device *pdev = to_platform_device(dev);
 769         struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 770
 771         clk_prepare_enable(i2c_dev->clk);
 772         /* take I2C out of reset */
 773         davinci_i2c_reset_ctrl(i2c_dev, 1);
 774
 775         return 0;
 776 }
 777
 778 static const struct dev_pm_ops davinci_i2c_pm = {
 779         .suspend        = davinci_i2c_suspend,
 780         .resume         = davinci_i2c_resume,
 781 };
 782
 783 #define davinci_i2c_pm_ops (&davinci_i2c_pm)
 784 #else
 785 #define davinci_i2c_pm_ops NULL
 786 #endif
 787
 788 /* work with hotplug and coldplug */
 789 MODULE_ALIAS("platform:i2c_davinci");
 790
 791 static struct platform_driver davinci_i2c_driver = {
 792         .probe          = davinci_i2c_probe,
 793         .remove         = davinci_i2c_remove,
 794         .driver         = {
 795                 .name   = "i2c_davinci",
 796                 .owner  = THIS_MODULE,
 797                 .pm     = davinci_i2c_pm_ops,
 798                 .of_match_table = davinci_i2c_of_match,
 799         },
 800 };
 801
 802 /* I2C may be needed to bring up other drivers */
 803 static int __init davinci_i2c_init_driver(void)
 804 {
 805         return platform_driver_register(&davinci_i2c_driver);
 806 }
 807 subsys_initcall(davinci_i2c_init_driver);
 808
 809 static void __exit davinci_i2c_exit_driver(void)
 810 {
 811         platform_driver_unregister(&davinci_i2c_driver);
 812 }
 813 module_exit(davinci_i2c_exit_driver);
 814
 815 MODULE_AUTHOR("Texas Instruments India");
 816 MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
 817 MODULE_LICENSE("GPL");