linux/drivers/i2c/busses/i2c-davinci.c
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   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#define DAVINCI_I2C_FUNC_REG    0x48
  64#define DAVINCI_I2C_DIR_REG     0x4c
  65#define DAVINCI_I2C_DIN_REG     0x50
  66#define DAVINCI_I2C_DOUT_REG    0x54
  67#define DAVINCI_I2C_DSET_REG    0x58
  68#define DAVINCI_I2C_DCLR_REG    0x5c
  69
  70#define DAVINCI_I2C_IVR_AAS     0x07
  71#define DAVINCI_I2C_IVR_SCD     0x06
  72#define DAVINCI_I2C_IVR_XRDY    0x05
  73#define DAVINCI_I2C_IVR_RDR     0x04
  74#define DAVINCI_I2C_IVR_ARDY    0x03
  75#define DAVINCI_I2C_IVR_NACK    0x02
  76#define DAVINCI_I2C_IVR_AL      0x01
  77
  78#define DAVINCI_I2C_STR_BB      BIT(12)
  79#define DAVINCI_I2C_STR_RSFULL  BIT(11)
  80#define DAVINCI_I2C_STR_SCD     BIT(5)
  81#define DAVINCI_I2C_STR_ARDY    BIT(2)
  82#define DAVINCI_I2C_STR_NACK    BIT(1)
  83#define DAVINCI_I2C_STR_AL      BIT(0)
  84
  85#define DAVINCI_I2C_MDR_NACK    BIT(15)
  86#define DAVINCI_I2C_MDR_STT     BIT(13)
  87#define DAVINCI_I2C_MDR_STP     BIT(11)
  88#define DAVINCI_I2C_MDR_MST     BIT(10)
  89#define DAVINCI_I2C_MDR_TRX     BIT(9)
  90#define DAVINCI_I2C_MDR_XA      BIT(8)
  91#define DAVINCI_I2C_MDR_RM      BIT(7)
  92#define DAVINCI_I2C_MDR_IRS     BIT(5)
  93
  94#define DAVINCI_I2C_IMR_AAS     BIT(6)
  95#define DAVINCI_I2C_IMR_SCD     BIT(5)
  96#define DAVINCI_I2C_IMR_XRDY    BIT(4)
  97#define DAVINCI_I2C_IMR_RRDY    BIT(3)
  98#define DAVINCI_I2C_IMR_ARDY    BIT(2)
  99#define DAVINCI_I2C_IMR_NACK    BIT(1)
 100#define DAVINCI_I2C_IMR_AL      BIT(0)
 101
 102/* set SDA and SCL as GPIO */
 103#define DAVINCI_I2C_FUNC_PFUNC0 BIT(0)
 104
 105/* set SCL as output when used as GPIO*/
 106#define DAVINCI_I2C_DIR_PDIR0   BIT(0)
 107/* set SDA as output when used as GPIO*/
 108#define DAVINCI_I2C_DIR_PDIR1   BIT(1)
 109
 110/* read SCL GPIO level */
 111#define DAVINCI_I2C_DIN_PDIN0 BIT(0)
 112/* read SDA GPIO level */
 113#define DAVINCI_I2C_DIN_PDIN1 BIT(1)
 114
 115/*set the SCL GPIO high */
 116#define DAVINCI_I2C_DSET_PDSET0 BIT(0)
 117/*set the SDA GPIO high */
 118#define DAVINCI_I2C_DSET_PDSET1 BIT(1)
 119
 120/* set the SCL GPIO low */
 121#define DAVINCI_I2C_DCLR_PDCLR0 BIT(0)
 122/* set the SDA GPIO low */
 123#define DAVINCI_I2C_DCLR_PDCLR1 BIT(1)
 124
 125struct davinci_i2c_dev {
 126        struct device           *dev;
 127        void __iomem            *base;
 128        struct completion       cmd_complete;
 129        struct clk              *clk;
 130        int                     cmd_err;
 131        u8                      *buf;
 132        size_t                  buf_len;
 133        int                     irq;
 134        int                     stop;
 135        u8                      terminate;
 136        struct i2c_adapter      adapter;
 137#ifdef CONFIG_CPU_FREQ
 138        struct completion       xfr_complete;
 139        struct notifier_block   freq_transition;
 140#endif
 141        struct davinci_i2c_platform_data *pdata;
 142};
 143
 144/* default platform data to use if not supplied in the platform_device */
 145static struct davinci_i2c_platform_data davinci_i2c_platform_data_default = {
 146        .bus_freq       = 100,
 147        .bus_delay      = 0,
 148};
 149
 150static inline void davinci_i2c_write_reg(struct davinci_i2c_dev *i2c_dev,
 151                                         int reg, u16 val)
 152{
 153        writew_relaxed(val, i2c_dev->base + reg);
 154}
 155
 156static inline u16 davinci_i2c_read_reg(struct davinci_i2c_dev *i2c_dev, int reg)
 157{
 158        return readw_relaxed(i2c_dev->base + reg);
 159}
 160
 161static inline void davinci_i2c_reset_ctrl(struct davinci_i2c_dev *i2c_dev,
 162                                                                int val)
 163{
 164        u16 w;
 165
 166        w = davinci_i2c_read_reg(i2c_dev, DAVINCI_I2C_MDR_REG);
 167        if (!val)       /* put I2C into reset */
 168                w &= ~DAVINCI_I2C_MDR_IRS;
 169        else            /* take I2C out of reset */
 170                w |= DAVINCI_I2C_MDR_IRS;
 171
 172        davinci_i2c_write_reg(i2c_dev, DAVINCI_I2C_MDR_REG, w);
 173}
 174
 175static void i2c_davinci_calc_clk_dividers(struct davinci_i2c_dev *dev)
 176{
 177        struct davinci_i2c_platform_data *pdata = dev->pdata;
 178        u16 psc;
 179        u32 clk;
 180        u32 d;
 181        u32 clkh;
 182        u32 clkl;
 183        u32 input_clock = clk_get_rate(dev->clk);
 184
 185        /* NOTE: I2C Clock divider programming info
 186         * As per I2C specs the following formulas provide prescaler
 187         * and low/high divider values
 188         * input clk --> PSC Div -----------> ICCL/H Div --> output clock
 189         *                       module clk
 190         *
 191         * output clk = module clk / (PSC + 1) [ (ICCL + d) + (ICCH + d) ]
 192         *
 193         * Thus,
 194         * (ICCL + ICCH) = clk = (input clk / ((psc +1) * output clk)) - 2d;
 195         *
 196         * where if PSC == 0, d = 7,
 197         *       if PSC == 1, d = 6
 198         *       if PSC > 1 , d = 5
 199         */
 200
 201        /* get minimum of 7 MHz clock, but max of 12 MHz */
 202        psc = (input_clock / 7000000) - 1;
 203        if ((input_clock / (psc + 1)) > 12000000)
 204                psc++;  /* better to run under spec than over */
 205        d = (psc >= 2) ? 5 : 7 - psc;
 206
 207        clk = ((input_clock / (psc + 1)) / (pdata->bus_freq * 1000)) - (d << 1);
 208        clkh = clk >> 1;
 209        clkl = clk - clkh;
 210
 211        davinci_i2c_write_reg(dev, DAVINCI_I2C_PSC_REG, psc);
 212        davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKH_REG, clkh);
 213        davinci_i2c_write_reg(dev, DAVINCI_I2C_CLKL_REG, clkl);
 214
 215        dev_dbg(dev->dev, "input_clock = %d, CLK = %d\n", input_clock, clk);
 216}
 217
 218/*
 219 * This function configures I2C and brings I2C out of reset.
 220 * This function is called during I2C init function. This function
 221 * also gets called if I2C encounters any errors.
 222 */
 223static int i2c_davinci_init(struct davinci_i2c_dev *dev)
 224{
 225        struct davinci_i2c_platform_data *pdata = dev->pdata;
 226
 227        /* put I2C into reset */
 228        davinci_i2c_reset_ctrl(dev, 0);
 229
 230        /* compute clock dividers */
 231        i2c_davinci_calc_clk_dividers(dev);
 232
 233        /* Respond at reserved "SMBus Host" slave address" (and zero);
 234         * we seem to have no option to not respond...
 235         */
 236        davinci_i2c_write_reg(dev, DAVINCI_I2C_OAR_REG, 0x08);
 237
 238        dev_dbg(dev->dev, "PSC  = %d\n",
 239                davinci_i2c_read_reg(dev, DAVINCI_I2C_PSC_REG));
 240        dev_dbg(dev->dev, "CLKL = %d\n",
 241                davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKL_REG));
 242        dev_dbg(dev->dev, "CLKH = %d\n",
 243                davinci_i2c_read_reg(dev, DAVINCI_I2C_CLKH_REG));
 244        dev_dbg(dev->dev, "bus_freq = %dkHz, bus_delay = %d\n",
 245                pdata->bus_freq, pdata->bus_delay);
 246
 247
 248        /* Take the I2C module out of reset: */
 249        davinci_i2c_reset_ctrl(dev, 1);
 250
 251        /* Enable interrupts */
 252        davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, I2C_DAVINCI_INTR_ALL);
 253
 254        return 0;
 255}
 256
 257/*
 258 * This routine does i2c bus recovery by using i2c_generic_gpio_recovery
 259 * which is provided by I2C Bus recovery infrastructure.
 260 */
 261static void davinci_i2c_prepare_recovery(struct i2c_adapter *adap)
 262{
 263        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 264
 265        /* Disable interrupts */
 266        davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, 0);
 267
 268        /* put I2C into reset */
 269        davinci_i2c_reset_ctrl(dev, 0);
 270}
 271
 272static void davinci_i2c_unprepare_recovery(struct i2c_adapter *adap)
 273{
 274        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 275
 276        i2c_davinci_init(dev);
 277}
 278
 279static struct i2c_bus_recovery_info davinci_i2c_gpio_recovery_info = {
 280        .recover_bus = i2c_generic_gpio_recovery,
 281        .prepare_recovery = davinci_i2c_prepare_recovery,
 282        .unprepare_recovery = davinci_i2c_unprepare_recovery,
 283};
 284
 285static void davinci_i2c_set_scl(struct i2c_adapter *adap, int val)
 286{
 287        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 288
 289        if (val)
 290                davinci_i2c_write_reg(dev, DAVINCI_I2C_DSET_REG,
 291                                      DAVINCI_I2C_DSET_PDSET0);
 292        else
 293                davinci_i2c_write_reg(dev, DAVINCI_I2C_DCLR_REG,
 294                                      DAVINCI_I2C_DCLR_PDCLR0);
 295}
 296
 297static int davinci_i2c_get_scl(struct i2c_adapter *adap)
 298{
 299        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 300        int val;
 301
 302        /* read the state of SCL */
 303        val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG);
 304        return val & DAVINCI_I2C_DIN_PDIN0;
 305}
 306
 307static int davinci_i2c_get_sda(struct i2c_adapter *adap)
 308{
 309        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 310        int val;
 311
 312        /* read the state of SDA */
 313        val = davinci_i2c_read_reg(dev, DAVINCI_I2C_DIN_REG);
 314        return val & DAVINCI_I2C_DIN_PDIN1;
 315}
 316
 317static void davinci_i2c_scl_prepare_recovery(struct i2c_adapter *adap)
 318{
 319        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 320
 321        davinci_i2c_prepare_recovery(adap);
 322
 323        /* SCL output, SDA input */
 324        davinci_i2c_write_reg(dev, DAVINCI_I2C_DIR_REG, DAVINCI_I2C_DIR_PDIR0);
 325
 326        /* change to GPIO mode */
 327        davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG,
 328                              DAVINCI_I2C_FUNC_PFUNC0);
 329}
 330
 331static void davinci_i2c_scl_unprepare_recovery(struct i2c_adapter *adap)
 332{
 333        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 334
 335        /* change back to I2C mode */
 336        davinci_i2c_write_reg(dev, DAVINCI_I2C_FUNC_REG, 0);
 337
 338        davinci_i2c_unprepare_recovery(adap);
 339}
 340
 341static struct i2c_bus_recovery_info davinci_i2c_scl_recovery_info = {
 342        .recover_bus = i2c_generic_scl_recovery,
 343        .set_scl = davinci_i2c_set_scl,
 344        .get_scl = davinci_i2c_get_scl,
 345        .get_sda = davinci_i2c_get_sda,
 346        .prepare_recovery = davinci_i2c_scl_prepare_recovery,
 347        .unprepare_recovery = davinci_i2c_scl_unprepare_recovery,
 348};
 349
 350/*
 351 * Waiting for bus not busy
 352 */
 353static int i2c_davinci_wait_bus_not_busy(struct davinci_i2c_dev *dev,
 354                                         char allow_sleep)
 355{
 356        unsigned long timeout;
 357        static u16 to_cnt;
 358
 359        timeout = jiffies + dev->adapter.timeout;
 360        while (davinci_i2c_read_reg(dev, DAVINCI_I2C_STR_REG)
 361               & DAVINCI_I2C_STR_BB) {
 362                if (to_cnt <= DAVINCI_I2C_MAX_TRIES) {
 363                        if (time_after(jiffies, timeout)) {
 364                                dev_warn(dev->dev,
 365                                "timeout waiting for bus ready\n");
 366                                to_cnt++;
 367                                return -ETIMEDOUT;
 368                        } else {
 369                                to_cnt = 0;
 370                                i2c_recover_bus(&dev->adapter);
 371                        }
 372                }
 373                if (allow_sleep)
 374                        schedule_timeout(1);
 375        }
 376
 377        return 0;
 378}
 379
 380/*
 381 * Low level master read/write transaction. This function is called
 382 * from i2c_davinci_xfer.
 383 */
 384static int
 385i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop)
 386{
 387        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 388        struct davinci_i2c_platform_data *pdata = dev->pdata;
 389        u32 flag;
 390        u16 w;
 391        unsigned long time_left;
 392
 393        /* Introduce a delay, required for some boards (e.g Davinci EVM) */
 394        if (pdata->bus_delay)
 395                udelay(pdata->bus_delay);
 396
 397        /* set the slave address */
 398        davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
 399
 400        dev->buf = msg->buf;
 401        dev->buf_len = msg->len;
 402        dev->stop = stop;
 403
 404        davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
 405
 406        reinit_completion(&dev->cmd_complete);
 407        dev->cmd_err = 0;
 408
 409        /* Take I2C out of reset and configure it as master */
 410        flag = DAVINCI_I2C_MDR_IRS | DAVINCI_I2C_MDR_MST;
 411
 412        /* if the slave address is ten bit address, enable XA bit */
 413        if (msg->flags & I2C_M_TEN)
 414                flag |= DAVINCI_I2C_MDR_XA;
 415        if (!(msg->flags & I2C_M_RD))
 416                flag |= DAVINCI_I2C_MDR_TRX;
 417        if (msg->len == 0)
 418                flag |= DAVINCI_I2C_MDR_RM;
 419
 420        /* Enable receive or transmit interrupts */
 421        w = davinci_i2c_read_reg(dev, DAVINCI_I2C_IMR_REG);
 422        if (msg->flags & I2C_M_RD)
 423                w |= DAVINCI_I2C_IMR_RRDY;
 424        else
 425                w |= DAVINCI_I2C_IMR_XRDY;
 426        davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w);
 427
 428        dev->terminate = 0;
 429
 430        /*
 431         * Write mode register first as needed for correct behaviour
 432         * on OMAP-L138, but don't set STT yet to avoid a race with XRDY
 433         * occurring before we have loaded DXR
 434         */
 435        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 436
 437        /*
 438         * First byte should be set here, not after interrupt,
 439         * because transmit-data-ready interrupt can come before
 440         * NACK-interrupt during sending of previous message and
 441         * ICDXR may have wrong data
 442         * It also saves us one interrupt, slightly faster
 443         */
 444        if ((!(msg->flags & I2C_M_RD)) && dev->buf_len) {
 445                davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG, *dev->buf++);
 446                dev->buf_len--;
 447        }
 448
 449        /* Set STT to begin transmit now DXR is loaded */
 450        flag |= DAVINCI_I2C_MDR_STT;
 451        if (stop && msg->len != 0)
 452                flag |= DAVINCI_I2C_MDR_STP;
 453        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag);
 454
 455        time_left = wait_for_completion_timeout(&dev->cmd_complete,
 456                                                dev->adapter.timeout);
 457        if (!time_left) {
 458                dev_err(dev->dev, "controller timed out\n");
 459                i2c_recover_bus(adap);
 460                dev->buf_len = 0;
 461                return -ETIMEDOUT;
 462        }
 463        if (dev->buf_len) {
 464                /* This should be 0 if all bytes were transferred
 465                 * or dev->cmd_err denotes an error.
 466                 */
 467                dev_err(dev->dev, "abnormal termination buf_len=%i\n",
 468                        dev->buf_len);
 469                dev->terminate = 1;
 470                wmb();
 471                dev->buf_len = 0;
 472                return -EREMOTEIO;
 473        }
 474
 475        /* no error */
 476        if (likely(!dev->cmd_err))
 477                return msg->len;
 478
 479        /* We have an error */
 480        if (dev->cmd_err & DAVINCI_I2C_STR_AL) {
 481                i2c_davinci_init(dev);
 482                return -EIO;
 483        }
 484
 485        if (dev->cmd_err & DAVINCI_I2C_STR_NACK) {
 486                if (msg->flags & I2C_M_IGNORE_NAK)
 487                        return msg->len;
 488                w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 489                w |= DAVINCI_I2C_MDR_STP;
 490                davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 491                return -EREMOTEIO;
 492        }
 493        return -EIO;
 494}
 495
 496/*
 497 * Prepare controller for a transaction and call i2c_davinci_xfer_msg
 498 */
 499static int
 500i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 501{
 502        struct davinci_i2c_dev *dev = i2c_get_adapdata(adap);
 503        int i;
 504        int ret;
 505
 506        dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
 507
 508        ret = i2c_davinci_wait_bus_not_busy(dev, 1);
 509        if (ret < 0) {
 510                dev_warn(dev->dev, "timeout waiting for bus ready\n");
 511                return ret;
 512        }
 513
 514        for (i = 0; i < num; i++) {
 515                ret = i2c_davinci_xfer_msg(adap, &msgs[i], (i == (num - 1)));
 516                dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
 517                        ret);
 518                if (ret < 0)
 519                        return ret;
 520        }
 521
 522#ifdef CONFIG_CPU_FREQ
 523        complete(&dev->xfr_complete);
 524#endif
 525
 526        return num;
 527}
 528
 529static u32 i2c_davinci_func(struct i2c_adapter *adap)
 530{
 531        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 532}
 533
 534static void terminate_read(struct davinci_i2c_dev *dev)
 535{
 536        u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 537        w |= DAVINCI_I2C_MDR_NACK;
 538        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 539
 540        /* Throw away data */
 541        davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG);
 542        if (!dev->terminate)
 543                dev_err(dev->dev, "RDR IRQ while no data requested\n");
 544}
 545static void terminate_write(struct davinci_i2c_dev *dev)
 546{
 547        u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG);
 548        w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP;
 549        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w);
 550
 551        if (!dev->terminate)
 552                dev_dbg(dev->dev, "TDR IRQ while no data to send\n");
 553}
 554
 555/*
 556 * Interrupt service routine. This gets called whenever an I2C interrupt
 557 * occurs.
 558 */
 559static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
 560{
 561        struct davinci_i2c_dev *dev = dev_id;
 562        u32 stat;
 563        int count = 0;
 564        u16 w;
 565
 566        while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
 567                dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
 568                if (count++ == 100) {
 569                        dev_warn(dev->dev, "Too much work in one IRQ\n");
 570                        break;
 571                }
 572
 573                switch (stat) {
 574                case DAVINCI_I2C_IVR_AL:
 575                        /* Arbitration lost, must retry */
 576                        dev->cmd_err |= DAVINCI_I2C_STR_AL;
 577                        dev->buf_len = 0;
 578                        complete(&dev->cmd_complete);
 579                        break;
 580
 581                case DAVINCI_I2C_IVR_NACK:
 582                        dev->cmd_err |= DAVINCI_I2C_STR_NACK;
 583                        dev->buf_len = 0;
 584                        complete(&dev->cmd_complete);
 585                        break;
 586
 587                case DAVINCI_I2C_IVR_ARDY:
 588                        davinci_i2c_write_reg(dev,
 589                                DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_ARDY);
 590                        if (((dev->buf_len == 0) && (dev->stop != 0)) ||
 591                            (dev->cmd_err & DAVINCI_I2C_STR_NACK)) {
 592                                w = davinci_i2c_read_reg(dev,
 593                                                         DAVINCI_I2C_MDR_REG);
 594                                w |= DAVINCI_I2C_MDR_STP;
 595                                davinci_i2c_write_reg(dev,
 596                                                      DAVINCI_I2C_MDR_REG, w);
 597                        }
 598                        complete(&dev->cmd_complete);
 599                        break;
 600
 601                case DAVINCI_I2C_IVR_RDR:
 602                        if (dev->buf_len) {
 603                                *dev->buf++ =
 604                                    davinci_i2c_read_reg(dev,
 605                                                         DAVINCI_I2C_DRR_REG);
 606                                dev->buf_len--;
 607                                if (dev->buf_len)
 608                                        continue;
 609
 610                                davinci_i2c_write_reg(dev,
 611                                        DAVINCI_I2C_STR_REG,
 612                                        DAVINCI_I2C_IMR_RRDY);
 613                        } else {
 614                                /* signal can terminate transfer */
 615                                terminate_read(dev);
 616                        }
 617                        break;
 618
 619                case DAVINCI_I2C_IVR_XRDY:
 620                        if (dev->buf_len) {
 621                                davinci_i2c_write_reg(dev, DAVINCI_I2C_DXR_REG,
 622                                                      *dev->buf++);
 623                                dev->buf_len--;
 624                                if (dev->buf_len)
 625                                        continue;
 626
 627                                w = davinci_i2c_read_reg(dev,
 628                                                         DAVINCI_I2C_IMR_REG);
 629                                w &= ~DAVINCI_I2C_IMR_XRDY;
 630                                davinci_i2c_write_reg(dev,
 631                                                      DAVINCI_I2C_IMR_REG,
 632                                                      w);
 633                        } else {
 634                                /* signal can terminate transfer */
 635                                terminate_write(dev);
 636                        }
 637                        break;
 638
 639                case DAVINCI_I2C_IVR_SCD:
 640                        davinci_i2c_write_reg(dev,
 641                                DAVINCI_I2C_STR_REG, DAVINCI_I2C_STR_SCD);
 642                        complete(&dev->cmd_complete);
 643                        break;
 644
 645                case DAVINCI_I2C_IVR_AAS:
 646                        dev_dbg(dev->dev, "Address as slave interrupt\n");
 647                        break;
 648
 649                default:
 650                        dev_warn(dev->dev, "Unrecognized irq stat %d\n", stat);
 651                        break;
 652                }
 653        }
 654
 655        return count ? IRQ_HANDLED : IRQ_NONE;
 656}
 657
 658#ifdef CONFIG_CPU_FREQ
 659static int i2c_davinci_cpufreq_transition(struct notifier_block *nb,
 660                                     unsigned long val, void *data)
 661{
 662        struct davinci_i2c_dev *dev;
 663
 664        dev = container_of(nb, struct davinci_i2c_dev, freq_transition);
 665        if (val == CPUFREQ_PRECHANGE) {
 666                wait_for_completion(&dev->xfr_complete);
 667                davinci_i2c_reset_ctrl(dev, 0);
 668        } else if (val == CPUFREQ_POSTCHANGE) {
 669                i2c_davinci_calc_clk_dividers(dev);
 670                davinci_i2c_reset_ctrl(dev, 1);
 671        }
 672
 673        return 0;
 674}
 675
 676static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
 677{
 678        dev->freq_transition.notifier_call = i2c_davinci_cpufreq_transition;
 679
 680        return cpufreq_register_notifier(&dev->freq_transition,
 681                                         CPUFREQ_TRANSITION_NOTIFIER);
 682}
 683
 684static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
 685{
 686        cpufreq_unregister_notifier(&dev->freq_transition,
 687                                    CPUFREQ_TRANSITION_NOTIFIER);
 688}
 689#else
 690static inline int i2c_davinci_cpufreq_register(struct davinci_i2c_dev *dev)
 691{
 692        return 0;
 693}
 694
 695static inline void i2c_davinci_cpufreq_deregister(struct davinci_i2c_dev *dev)
 696{
 697}
 698#endif
 699
 700static struct i2c_algorithm i2c_davinci_algo = {
 701        .master_xfer    = i2c_davinci_xfer,
 702        .functionality  = i2c_davinci_func,
 703};
 704
 705static const struct of_device_id davinci_i2c_of_match[] = {
 706        {.compatible = "ti,davinci-i2c", },
 707        {},
 708};
 709MODULE_DEVICE_TABLE(of, davinci_i2c_of_match);
 710
 711static int davinci_i2c_probe(struct platform_device *pdev)
 712{
 713        struct davinci_i2c_dev *dev;
 714        struct i2c_adapter *adap;
 715        struct resource *mem;
 716        int r, irq;
 717
 718        irq = platform_get_irq(pdev, 0);
 719        if (irq <= 0) {
 720                if (!irq)
 721                        irq = -ENXIO;
 722                if (irq != -EPROBE_DEFER)
 723                        dev_err(&pdev->dev,
 724                                "can't get irq resource ret=%d\n", irq);
 725                return irq;
 726        }
 727
 728        dev = devm_kzalloc(&pdev->dev, sizeof(struct davinci_i2c_dev),
 729                        GFP_KERNEL);
 730        if (!dev) {
 731                dev_err(&pdev->dev, "Memory allocation failed\n");
 732                return -ENOMEM;
 733        }
 734
 735        init_completion(&dev->cmd_complete);
 736#ifdef CONFIG_CPU_FREQ
 737        init_completion(&dev->xfr_complete);
 738#endif
 739        dev->dev = &pdev->dev;
 740        dev->irq = irq;
 741        dev->pdata = dev_get_platdata(&pdev->dev);
 742        platform_set_drvdata(pdev, dev);
 743
 744        if (!dev->pdata && pdev->dev.of_node) {
 745                u32 prop;
 746
 747                dev->pdata = devm_kzalloc(&pdev->dev,
 748                        sizeof(struct davinci_i2c_platform_data), GFP_KERNEL);
 749                if (!dev->pdata)
 750                        return -ENOMEM;
 751
 752                memcpy(dev->pdata, &davinci_i2c_platform_data_default,
 753                        sizeof(struct davinci_i2c_platform_data));
 754                if (!of_property_read_u32(pdev->dev.of_node, "clock-frequency",
 755                        &prop))
 756                        dev->pdata->bus_freq = prop / 1000;
 757
 758                dev->pdata->has_pfunc =
 759                        of_property_read_bool(pdev->dev.of_node,
 760                                              "ti,has-pfunc");
 761        } else if (!dev->pdata) {
 762                dev->pdata = &davinci_i2c_platform_data_default;
 763        }
 764
 765        dev->clk = devm_clk_get(&pdev->dev, NULL);
 766        if (IS_ERR(dev->clk))
 767                return -ENODEV;
 768        clk_prepare_enable(dev->clk);
 769
 770        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 771        dev->base = devm_ioremap_resource(&pdev->dev, mem);
 772        if (IS_ERR(dev->base)) {
 773                r = PTR_ERR(dev->base);
 774                goto err_unuse_clocks;
 775        }
 776
 777        i2c_davinci_init(dev);
 778
 779        r = devm_request_irq(&pdev->dev, dev->irq, i2c_davinci_isr, 0,
 780                        pdev->name, dev);
 781        if (r) {
 782                dev_err(&pdev->dev, "failure requesting irq %i\n", dev->irq);
 783                goto err_unuse_clocks;
 784        }
 785
 786        r = i2c_davinci_cpufreq_register(dev);
 787        if (r) {
 788                dev_err(&pdev->dev, "failed to register cpufreq\n");
 789                goto err_unuse_clocks;
 790        }
 791
 792        adap = &dev->adapter;
 793        i2c_set_adapdata(adap, dev);
 794        adap->owner = THIS_MODULE;
 795        adap->class = I2C_CLASS_DEPRECATED;
 796        strlcpy(adap->name, "DaVinci I2C adapter", sizeof(adap->name));
 797        adap->algo = &i2c_davinci_algo;
 798        adap->dev.parent = &pdev->dev;
 799        adap->timeout = DAVINCI_I2C_TIMEOUT;
 800        adap->dev.of_node = pdev->dev.of_node;
 801
 802        if (dev->pdata->has_pfunc)
 803                adap->bus_recovery_info = &davinci_i2c_scl_recovery_info;
 804        else if (dev->pdata->scl_pin) {
 805                adap->bus_recovery_info = &davinci_i2c_gpio_recovery_info;
 806                adap->bus_recovery_info->scl_gpio = dev->pdata->scl_pin;
 807                adap->bus_recovery_info->sda_gpio = dev->pdata->sda_pin;
 808        }
 809
 810        adap->nr = pdev->id;
 811        r = i2c_add_numbered_adapter(adap);
 812        if (r) {
 813                dev_err(&pdev->dev, "failure adding adapter\n");
 814                goto err_unuse_clocks;
 815        }
 816
 817        return 0;
 818
 819err_unuse_clocks:
 820        clk_disable_unprepare(dev->clk);
 821        dev->clk = NULL;
 822        return r;
 823}
 824
 825static int davinci_i2c_remove(struct platform_device *pdev)
 826{
 827        struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
 828
 829        i2c_davinci_cpufreq_deregister(dev);
 830
 831        i2c_del_adapter(&dev->adapter);
 832
 833        clk_disable_unprepare(dev->clk);
 834        dev->clk = NULL;
 835
 836        davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
 837
 838        return 0;
 839}
 840
 841#ifdef CONFIG_PM
 842static int davinci_i2c_suspend(struct device *dev)
 843{
 844        struct platform_device *pdev = to_platform_device(dev);
 845        struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 846
 847        /* put I2C into reset */
 848        davinci_i2c_reset_ctrl(i2c_dev, 0);
 849        clk_disable_unprepare(i2c_dev->clk);
 850
 851        return 0;
 852}
 853
 854static int davinci_i2c_resume(struct device *dev)
 855{
 856        struct platform_device *pdev = to_platform_device(dev);
 857        struct davinci_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 858
 859        clk_prepare_enable(i2c_dev->clk);
 860        /* take I2C out of reset */
 861        davinci_i2c_reset_ctrl(i2c_dev, 1);
 862
 863        return 0;
 864}
 865
 866static const struct dev_pm_ops davinci_i2c_pm = {
 867        .suspend        = davinci_i2c_suspend,
 868        .resume         = davinci_i2c_resume,
 869};
 870
 871#define davinci_i2c_pm_ops (&davinci_i2c_pm)
 872#else
 873#define davinci_i2c_pm_ops NULL
 874#endif
 875
 876/* work with hotplug and coldplug */
 877MODULE_ALIAS("platform:i2c_davinci");
 878
 879static struct platform_driver davinci_i2c_driver = {
 880        .probe          = davinci_i2c_probe,
 881        .remove         = davinci_i2c_remove,
 882        .driver         = {
 883                .name   = "i2c_davinci",
 884                .pm     = davinci_i2c_pm_ops,
 885                .of_match_table = davinci_i2c_of_match,
 886        },
 887};
 888
 889/* I2C may be needed to bring up other drivers */
 890static int __init davinci_i2c_init_driver(void)
 891{
 892        return platform_driver_register(&davinci_i2c_driver);
 893}
 894subsys_initcall(davinci_i2c_init_driver);
 895
 896static void __exit davinci_i2c_exit_driver(void)
 897{
 898        platform_driver_unregister(&davinci_i2c_driver);
 899}
 900module_exit(davinci_i2c_exit_driver);
 901
 902MODULE_AUTHOR("Texas Instruments India");
 903MODULE_DESCRIPTION("TI DaVinci I2C bus adapter");
 904MODULE_LICENSE("GPL");
 905