drivers/i2c/busses/i2c-omap.c

   1 /*
   2  * TI OMAP I2C master mode driver
   3  *
   4  * Copyright (C) 2003 MontaVista Software, Inc.
   5  * Copyright (C) 2005 Nokia Corporation
   6  * Copyright (C) 2004 - 2007 Texas Instruments.
   7  *
   8  * Originally written by MontaVista Software, Inc.
   9  * Additional contributions by:
  10  *      Tony Lindgren <tony@atomide.com>
  11  *      Imre Deak <imre.deak@nokia.com>
  12  *      Juha Yrjölä <juha.yrjola@solidboot.com>
  13  *      Syed Khasim <x0khasim@ti.com>
  14  *      Nishant Menon <nm@ti.com>
  15  *
  16  * This program is free software; you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License as published by
  18  * the Free Software Foundation; either version 2 of the License, or
  19  * (at your option) any later version.
  20  *
  21  * This program is distributed in the hope that it will be useful,
  22  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  24  * GNU General Public License for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License
  27  * along with this program; if not, write to the Free Software
  28  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  29  */
  30
  31 #include <linux/module.h>
  32 #include <linux/delay.h>
  33 #include <linux/i2c.h>
  34 #include <linux/err.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/completion.h>
  37 #include <linux/platform_device.h>
  38 #include <linux/clk.h>
  39 #include <linux/io.h>
  40
  41 /* I2C controller revisions */
  42 #define OMAP_I2C_REV_2                  0x20
  43
  44 /* I2C controller revisions present on specific hardware */
  45 #define OMAP_I2C_REV_ON_2430            0x36
  46 #define OMAP_I2C_REV_ON_3430            0x3C
  47
  48 /* timeout waiting for the controller to respond */
  49 #define OMAP_I2C_TIMEOUT (msecs_to_jiffies(1000))
  50
  51 #define OMAP_I2C_REV_REG                0x00
  52 #define OMAP_I2C_IE_REG                 0x04
  53 #define OMAP_I2C_STAT_REG               0x08
  54 #define OMAP_I2C_IV_REG                 0x0c
  55 /* For OMAP3 I2C_IV has changed to I2C_WE (wakeup enable) */
  56 #define OMAP_I2C_WE_REG                 0x0c
  57 #define OMAP_I2C_SYSS_REG               0x10
  58 #define OMAP_I2C_BUF_REG                0x14
  59 #define OMAP_I2C_CNT_REG                0x18
  60 #define OMAP_I2C_DATA_REG               0x1c
  61 #define OMAP_I2C_SYSC_REG               0x20
  62 #define OMAP_I2C_CON_REG                0x24
  63 #define OMAP_I2C_OA_REG                 0x28
  64 #define OMAP_I2C_SA_REG                 0x2c
  65 #define OMAP_I2C_PSC_REG                0x30
  66 #define OMAP_I2C_SCLL_REG               0x34
  67 #define OMAP_I2C_SCLH_REG               0x38
  68 #define OMAP_I2C_SYSTEST_REG            0x3c
  69 #define OMAP_I2C_BUFSTAT_REG            0x40
  70
  71 /* I2C Interrupt Enable Register (OMAP_I2C_IE): */
  72 #define OMAP_I2C_IE_XDR         (1 << 14)       /* TX Buffer drain int enable */
  73 #define OMAP_I2C_IE_RDR         (1 << 13)       /* RX Buffer drain int enable */
  74 #define OMAP_I2C_IE_XRDY        (1 << 4)        /* TX data ready int enable */
  75 #define OMAP_I2C_IE_RRDY        (1 << 3)        /* RX data ready int enable */
  76 #define OMAP_I2C_IE_ARDY        (1 << 2)        /* Access ready int enable */
  77 #define OMAP_I2C_IE_NACK        (1 << 1)        /* No ack interrupt enable */
  78 #define OMAP_I2C_IE_AL          (1 << 0)        /* Arbitration lost int ena */
  79
  80 /* I2C Status Register (OMAP_I2C_STAT): */
  81 #define OMAP_I2C_STAT_XDR       (1 << 14)       /* TX Buffer draining */
  82 #define OMAP_I2C_STAT_RDR       (1 << 13)       /* RX Buffer draining */
  83 #define OMAP_I2C_STAT_BB        (1 << 12)       /* Bus busy */
  84 #define OMAP_I2C_STAT_ROVR      (1 << 11)       /* Receive overrun */
  85 #define OMAP_I2C_STAT_XUDF      (1 << 10)       /* Transmit underflow */
  86 #define OMAP_I2C_STAT_AAS       (1 << 9)        /* Address as slave */
  87 #define OMAP_I2C_STAT_AD0       (1 << 8)        /* Address zero */
  88 #define OMAP_I2C_STAT_XRDY      (1 << 4)        /* Transmit data ready */
  89 #define OMAP_I2C_STAT_RRDY      (1 << 3)        /* Receive data ready */
  90 #define OMAP_I2C_STAT_ARDY      (1 << 2)        /* Register access ready */
  91 #define OMAP_I2C_STAT_NACK      (1 << 1)        /* No ack interrupt enable */
  92 #define OMAP_I2C_STAT_AL        (1 << 0)        /* Arbitration lost int ena */
  93
  94 /* I2C WE wakeup enable register */
  95 #define OMAP_I2C_WE_XDR_WE      (1 << 14)       /* TX drain wakup */
  96 #define OMAP_I2C_WE_RDR_WE      (1 << 13)       /* RX drain wakeup */
  97 #define OMAP_I2C_WE_AAS_WE      (1 << 9)        /* Address as slave wakeup*/
  98 #define OMAP_I2C_WE_BF_WE       (1 << 8)        /* Bus free wakeup */
  99 #define OMAP_I2C_WE_STC_WE      (1 << 6)        /* Start condition wakeup */
 100 #define OMAP_I2C_WE_GC_WE       (1 << 5)        /* General call wakeup */
 101 #define OMAP_I2C_WE_DRDY_WE     (1 << 3)        /* TX/RX data ready wakeup */
 102 #define OMAP_I2C_WE_ARDY_WE     (1 << 2)        /* Reg access ready wakeup */
 103 #define OMAP_I2C_WE_NACK_WE     (1 << 1)        /* No acknowledgment wakeup */
 104 #define OMAP_I2C_WE_AL_WE       (1 << 0)        /* Arbitration lost wakeup */
 105
 106 #define OMAP_I2C_WE_ALL         (OMAP_I2C_WE_XDR_WE | OMAP_I2C_WE_RDR_WE | \
 107                                 OMAP_I2C_WE_AAS_WE | OMAP_I2C_WE_BF_WE | \
 108                                 OMAP_I2C_WE_STC_WE | OMAP_I2C_WE_GC_WE | \
 109                                 OMAP_I2C_WE_DRDY_WE | OMAP_I2C_WE_ARDY_WE | \
 110                                 OMAP_I2C_WE_NACK_WE | OMAP_I2C_WE_AL_WE)
 111
 112 /* I2C Buffer Configuration Register (OMAP_I2C_BUF): */
 113 #define OMAP_I2C_BUF_RDMA_EN    (1 << 15)       /* RX DMA channel enable */
 114 #define OMAP_I2C_BUF_RXFIF_CLR  (1 << 14)       /* RX FIFO Clear */
 115 #define OMAP_I2C_BUF_XDMA_EN    (1 << 7)        /* TX DMA channel enable */
 116 #define OMAP_I2C_BUF_TXFIF_CLR  (1 << 6)        /* TX FIFO Clear */
 117
 118 /* I2C Configuration Register (OMAP_I2C_CON): */
 119 #define OMAP_I2C_CON_EN         (1 << 15)       /* I2C module enable */
 120 #define OMAP_I2C_CON_BE         (1 << 14)       /* Big endian mode */
 121 #define OMAP_I2C_CON_OPMODE_HS  (1 << 12)       /* High Speed support */
 122 #define OMAP_I2C_CON_STB        (1 << 11)       /* Start byte mode (master) */
 123 #define OMAP_I2C_CON_MST        (1 << 10)       /* Master/slave mode */
 124 #define OMAP_I2C_CON_TRX        (1 << 9)        /* TX/RX mode (master only) */
 125 #define OMAP_I2C_CON_XA         (1 << 8)        /* Expand address */
 126 #define OMAP_I2C_CON_RM         (1 << 2)        /* Repeat mode (master only) */
 127 #define OMAP_I2C_CON_STP        (1 << 1)        /* Stop cond (master only) */
 128 #define OMAP_I2C_CON_STT        (1 << 0)        /* Start condition (master) */
 129
 130 /* I2C SCL time value when Master */
 131 #define OMAP_I2C_SCLL_HSSCLL    8
 132 #define OMAP_I2C_SCLH_HSSCLH    8
 133
 134 /* I2C System Test Register (OMAP_I2C_SYSTEST): */
 135 #ifdef DEBUG
 136 #define OMAP_I2C_SYSTEST_ST_EN          (1 << 15)       /* System test enable */
 137 #define OMAP_I2C_SYSTEST_FREE           (1 << 14)       /* Free running mode */
 138 #define OMAP_I2C_SYSTEST_TMODE_MASK     (3 << 12)       /* Test mode select */
 139 #define OMAP_I2C_SYSTEST_TMODE_SHIFT    (12)            /* Test mode select */
 140 #define OMAP_I2C_SYSTEST_SCL_I          (1 << 3)        /* SCL line sense in */
 141 #define OMAP_I2C_SYSTEST_SCL_O          (1 << 2)        /* SCL line drive out */
 142 #define OMAP_I2C_SYSTEST_SDA_I          (1 << 1)        /* SDA line sense in */
 143 #define OMAP_I2C_SYSTEST_SDA_O          (1 << 0)        /* SDA line drive out */
 144 #endif
 145
 146 /* OCP_SYSSTATUS bit definitions */
 147 #define SYSS_RESETDONE_MASK             (1 << 0)
 148
 149 /* OCP_SYSCONFIG bit definitions */
 150 #define SYSC_CLOCKACTIVITY_MASK         (0x3 << 8)
 151 #define SYSC_SIDLEMODE_MASK             (0x3 << 3)
 152 #define SYSC_ENAWAKEUP_MASK             (1 << 2)
 153 #define SYSC_SOFTRESET_MASK             (1 << 1)
 154 #define SYSC_AUTOIDLE_MASK              (1 << 0)
 155
 156 #define SYSC_IDLEMODE_SMART             0x2
 157 #define SYSC_CLOCKACTIVITY_FCLK         0x2
 158
 159
 160 struct omap_i2c_dev {
 161         struct device           *dev;
 162         void __iomem            *base;          /* virtual */
 163         int                     irq;
 164         struct clk              *iclk;          /* Interface clock */
 165         struct clk              *fclk;          /* Functional clock */
 166         struct completion       cmd_complete;
 167         struct resource         *ioarea;
 168         u32                     speed;          /* Speed of bus in Khz */
 169         u16                     cmd_err;
 170         u8                      *buf;
 171         size_t                  buf_len;
 172         struct i2c_adapter      adapter;
 173         u8                      fifo_size;      /* use as flag and value
 174                                                  * fifo_size==0 implies no fifo
 175                                                  * if set, should be trsh+1
 176                                                  */
 177         u8                      rev;
 178         unsigned                b_hw:1;         /* bad h/w fixes */
 179         unsigned                idle:1;
 180         u16                     iestate;        /* Saved interrupt register */
 181 };
 182
 183 static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev,
 184                                       int reg, u16 val)
 185 {
 186         __raw_writew(val, i2c_dev->base + reg);
 187 }
 188
 189 static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
 190 {
 191         return __raw_readw(i2c_dev->base + reg);
 192 }
 193
 194 static int __init omap_i2c_get_clocks(struct omap_i2c_dev *dev)
 195 {
 196         int ret;
 197
 198         dev->iclk = clk_get(dev->dev, "ick");
 199         if (IS_ERR(dev->iclk)) {
 200                 ret = PTR_ERR(dev->iclk);
 201                 dev->iclk = NULL;
 202                 return ret;
 203         }
 204
 205         dev->fclk = clk_get(dev->dev, "fck");
 206         if (IS_ERR(dev->fclk)) {
 207                 ret = PTR_ERR(dev->fclk);
 208                 if (dev->iclk != NULL) {
 209                         clk_put(dev->iclk);
 210                         dev->iclk = NULL;
 211                 }
 212                 dev->fclk = NULL;
 213                 return ret;
 214         }
 215
 216         return 0;
 217 }
 218
 219 static void omap_i2c_put_clocks(struct omap_i2c_dev *dev)
 220 {
 221         clk_put(dev->fclk);
 222         dev->fclk = NULL;
 223         clk_put(dev->iclk);
 224         dev->iclk = NULL;
 225 }
 226
 227 static void omap_i2c_unidle(struct omap_i2c_dev *dev)
 228 {
 229         WARN_ON(!dev->idle);
 230
 231         clk_enable(dev->iclk);
 232         clk_enable(dev->fclk);
 233         dev->idle = 0;
 234         if (dev->iestate)
 235                 omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
 236 }
 237
 238 static void omap_i2c_idle(struct omap_i2c_dev *dev)
 239 {
 240         u16 iv;
 241
 242         WARN_ON(dev->idle);
 243
 244         dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
 245         omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);
 246         if (dev->rev < OMAP_I2C_REV_2) {
 247                 iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); /* Read clears */
 248         } else {
 249                 omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate);
 250
 251                 /* Flush posted write before the dev->idle store occurs */
 252                 omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
 253         }
 254         dev->idle = 1;
 255         clk_disable(dev->fclk);
 256         clk_disable(dev->iclk);
 257 }
 258
 259 static int omap_i2c_init(struct omap_i2c_dev *dev)
 260 {
 261         u16 psc = 0, scll = 0, sclh = 0;
 262         u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
 263         unsigned long fclk_rate = 12000000;
 264         unsigned long timeout;
 265         unsigned long internal_clk = 0;
 266
 267         if (dev->rev >= OMAP_I2C_REV_2) {
 268                 omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, SYSC_SOFTRESET_MASK);
 269                 /* For some reason we need to set the EN bit before the
 270                  * reset done bit gets set. */
 271                 timeout = jiffies + OMAP_I2C_TIMEOUT;
 272                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
 273                 while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) &
 274                          SYSS_RESETDONE_MASK)) {
 275                         if (time_after(jiffies, timeout)) {
 276                                 dev_warn(dev->dev, "timeout waiting "
 277                                                 "for controller reset\n");
 278                                 return -ETIMEDOUT;
 279                         }
 280                         msleep(1);
 281                 }
 282
 283                 /* SYSC register is cleared by the reset; rewrite it */
 284                 if (dev->rev == OMAP_I2C_REV_ON_2430) {
 285
 286                         omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
 287                                            SYSC_AUTOIDLE_MASK);
 288
 289                 } else if (dev->rev >= OMAP_I2C_REV_ON_3430) {
 290                         u32 v;
 291
 292                         v = SYSC_AUTOIDLE_MASK;
 293                         v |= SYSC_ENAWAKEUP_MASK;
 294                         v |= (SYSC_IDLEMODE_SMART <<
 295                               __ffs(SYSC_SIDLEMODE_MASK));
 296                         v |= (SYSC_CLOCKACTIVITY_FCLK <<
 297                               __ffs(SYSC_CLOCKACTIVITY_MASK));
 298
 299                         omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, v);
 300                         /*
 301                          * Enabling all wakup sources to stop I2C freezing on
 302                          * WFI instruction.
 303                          * REVISIT: Some wkup sources might not be needed.
 304                          */
 305                         omap_i2c_write_reg(dev, OMAP_I2C_WE_REG,
 306                                                         OMAP_I2C_WE_ALL);
 307
 308                 }
 309         }
 310         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 311
 312         if (cpu_class_is_omap1()) {
 313                 /*
 314                  * The I2C functional clock is the armxor_ck, so there's
 315                  * no need to get "armxor_ck" separately.  Now, if OMAP2420
 316                  * always returns 12MHz for the functional clock, we can
 317                  * do this bit unconditionally.
 318                  */
 319                 fclk_rate = clk_get_rate(dev->fclk);
 320
 321                 /* TRM for 5912 says the I2C clock must be prescaled to be
 322                  * between 7 - 12 MHz. The XOR input clock is typically
 323                  * 12, 13 or 19.2 MHz. So we should have code that produces:
 324                  *
 325                  * XOR MHz      Divider         Prescaler
 326                  * 12           1               0
 327                  * 13           2               1
 328                  * 19.2         2               1
 329                  */
 330                 if (fclk_rate > 12000000)
 331                         psc = fclk_rate / 12000000;
 332         }
 333
 334         if (cpu_is_omap2430() || cpu_is_omap34xx()) {
 335
 336                 /* HSI2C controller internal clk rate should be 19.2 Mhz */
 337                 internal_clk = 19200;
 338                 fclk_rate = clk_get_rate(dev->fclk) / 1000;
 339
 340                 /* Compute prescaler divisor */
 341                 psc = fclk_rate / internal_clk;
 342                 psc = psc - 1;
 343
 344                 /* If configured for High Speed */
 345                 if (dev->speed > 400) {
 346                         /* For first phase of HS mode */
 347                         fsscll = internal_clk / (400 * 2) - 6;
 348                         fssclh = internal_clk / (400 * 2) - 6;
 349
 350                         /* For second phase of HS mode */
 351                         hsscll = fclk_rate / (dev->speed * 2) - 6;
 352                         hssclh = fclk_rate / (dev->speed * 2) - 6;
 353                 } else {
 354                         /* To handle F/S modes */
 355                         fsscll = internal_clk / (dev->speed * 2) - 6;
 356                         fssclh = internal_clk / (dev->speed * 2) - 6;
 357                 }
 358                 scll = (hsscll << OMAP_I2C_SCLL_HSSCLL) | fsscll;
 359                 sclh = (hssclh << OMAP_I2C_SCLH_HSSCLH) | fssclh;
 360         } else {
 361                 /* Program desired operating rate */
 362                 fclk_rate /= (psc + 1) * 1000;
 363                 if (psc > 2)
 364                         psc = 2;
 365                 scll = fclk_rate / (dev->speed * 2) - 7 + psc;
 366                 sclh = fclk_rate / (dev->speed * 2) - 7 + psc;
 367         }
 368
 369         /* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
 370         omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc);
 371
 372         /* SCL low and high time values */
 373         omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);
 374         omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);
 375
 376         if (dev->fifo_size)
 377                 /* Note: setup required fifo size - 1 */
 378                 omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG,
 379                                         (dev->fifo_size - 1) << 8 | /* RTRSH */
 380                                         OMAP_I2C_BUF_RXFIF_CLR |
 381                                         (dev->fifo_size - 1) | /* XTRSH */
 382                                         OMAP_I2C_BUF_TXFIF_CLR);
 383
 384         /* Take the I2C module out of reset: */
 385         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
 386
 387         /* Enable interrupts */
 388         omap_i2c_write_reg(dev, OMAP_I2C_IE_REG,
 389                         (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
 390                         OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |
 391                         OMAP_I2C_IE_AL)  | ((dev->fifo_size) ?
 392                                 (OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0));
 393         return 0;
 394 }
 395
 396 /*
 397  * Waiting on Bus Busy
 398  */
 399 static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev)
 400 {
 401         unsigned long timeout;
 402
 403         timeout = jiffies + OMAP_I2C_TIMEOUT;
 404         while (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) {
 405                 if (time_after(jiffies, timeout)) {
 406                         dev_warn(dev->dev, "timeout waiting for bus ready\n");
 407                         return -ETIMEDOUT;
 408                 }
 409                 msleep(1);
 410         }
 411
 412         return 0;
 413 }
 414
 415 /*
 416  * Low level master read/write transaction.
 417  */
 418 static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
 419                              struct i2c_msg *msg, int stop)
 420 {
 421         struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
 422         int r;
 423         u16 w;
 424
 425         dev_dbg(dev->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
 426                 msg->addr, msg->len, msg->flags, stop);
 427
 428         if (msg->len == 0)
 429                 return -EINVAL;
 430
 431         omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr);
 432
 433         /* REVISIT: Could the STB bit of I2C_CON be used with probing? */
 434         dev->buf = msg->buf;
 435         dev->buf_len = msg->len;
 436
 437         omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len);
 438
 439         /* Clear the FIFO Buffers */
 440         w = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG);
 441         w |= OMAP_I2C_BUF_RXFIF_CLR | OMAP_I2C_BUF_TXFIF_CLR;
 442         omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, w);
 443
 444         init_completion(&dev->cmd_complete);
 445         dev->cmd_err = 0;
 446
 447         w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
 448
 449         /* High speed configuration */
 450         if (dev->speed > 400)
 451                 w |= OMAP_I2C_CON_OPMODE_HS;
 452
 453         if (msg->flags & I2C_M_TEN)
 454                 w |= OMAP_I2C_CON_XA;
 455         if (!(msg->flags & I2C_M_RD))
 456                 w |= OMAP_I2C_CON_TRX;
 457
 458         if (!dev->b_hw && stop)
 459                 w |= OMAP_I2C_CON_STP;
 460
 461         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
 462
 463         /*
 464          * Don't write stt and stp together on some hardware.
 465          */
 466         if (dev->b_hw && stop) {
 467                 unsigned long delay = jiffies + OMAP_I2C_TIMEOUT;
 468                 u16 con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
 469                 while (con & OMAP_I2C_CON_STT) {
 470                         con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
 471
 472                         /* Let the user know if i2c is in a bad state */
 473                         if (time_after(jiffies, delay)) {
 474                                 dev_err(dev->dev, "controller timed out "
 475                                 "waiting for start condition to finish\n");
 476                                 return -ETIMEDOUT;
 477                         }
 478                         cpu_relax();
 479                 }
 480
 481                 w |= OMAP_I2C_CON_STP;
 482                 w &= ~OMAP_I2C_CON_STT;
 483                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
 484         }
 485
 486         /*
 487          * REVISIT: We should abort the transfer on signals, but the bus goes
 488          * into arbitration and we're currently unable to recover from it.
 489          */
 490         r = wait_for_completion_timeout(&dev->cmd_complete,
 491                                         OMAP_I2C_TIMEOUT);
 492         dev->buf_len = 0;
 493         if (r < 0)
 494                 return r;
 495         if (r == 0) {
 496                 dev_err(dev->dev, "controller timed out\n");
 497                 omap_i2c_init(dev);
 498                 return -ETIMEDOUT;
 499         }
 500
 501         if (likely(!dev->cmd_err))
 502                 return 0;
 503
 504         /* We have an error */
 505         if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
 506                             OMAP_I2C_STAT_XUDF)) {
 507                 omap_i2c_init(dev);
 508                 return -EIO;
 509         }
 510
 511         if (dev->cmd_err & OMAP_I2C_STAT_NACK) {
 512                 if (msg->flags & I2C_M_IGNORE_NAK)
 513                         return 0;
 514                 if (stop) {
 515                         w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
 516                         w |= OMAP_I2C_CON_STP;
 517                         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
 518                 }
 519                 return -EREMOTEIO;
 520         }
 521         return -EIO;
 522 }
 523
 524
 525 /*
 526  * Prepare controller for a transaction and call omap_i2c_xfer_msg
 527  * to do the work during IRQ processing.
 528  */
 529 static int
 530 omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 531 {
 532         struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
 533         int i;
 534         int r;
 535
 536         omap_i2c_unidle(dev);
 537
 538         r = omap_i2c_wait_for_bb(dev);
 539         if (r < 0)
 540                 goto out;
 541
 542         for (i = 0; i < num; i++) {
 543                 r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
 544                 if (r != 0)
 545                         break;
 546         }
 547
 548         if (r == 0)
 549                 r = num;
 550 out:
 551         omap_i2c_idle(dev);
 552         return r;
 553 }
 554
 555 static u32
 556 omap_i2c_func(struct i2c_adapter *adap)
 557 {
 558         return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
 559 }
 560
 561 static inline void
 562 omap_i2c_complete_cmd(struct omap_i2c_dev *dev, u16 err)
 563 {
 564         dev->cmd_err |= err;
 565         complete(&dev->cmd_complete);
 566 }
 567
 568 static inline void
 569 omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat)
 570 {
 571         omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
 572 }
 573
 574 /* rev1 devices are apparently only on some 15xx */
 575 #ifdef CONFIG_ARCH_OMAP15XX
 576
 577 static irqreturn_t
 578 omap_i2c_rev1_isr(int this_irq, void *dev_id)
 579 {
 580         struct omap_i2c_dev *dev = dev_id;
 581         u16 iv, w;
 582
 583         if (dev->idle)
 584                 return IRQ_NONE;
 585
 586         iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
 587         switch (iv) {
 588         case 0x00:      /* None */
 589                 break;
 590         case 0x01:      /* Arbitration lost */
 591                 dev_err(dev->dev, "Arbitration lost\n");
 592                 omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
 593                 break;
 594         case 0x02:      /* No acknowledgement */
 595                 omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
 596                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP);
 597                 break;
 598         case 0x03:      /* Register access ready */
 599                 omap_i2c_complete_cmd(dev, 0);
 600                 break;
 601         case 0x04:      /* Receive data ready */
 602                 if (dev->buf_len) {
 603                         w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
 604                         *dev->buf++ = w;
 605                         dev->buf_len--;
 606                         if (dev->buf_len) {
 607                                 *dev->buf++ = w >> 8;
 608                                 dev->buf_len--;
 609                         }
 610                 } else
 611                         dev_err(dev->dev, "RRDY IRQ while no data requested\n");
 612                 break;
 613         case 0x05:      /* Transmit data ready */
 614                 if (dev->buf_len) {
 615                         w = *dev->buf++;
 616                         dev->buf_len--;
 617                         if (dev->buf_len) {
 618                                 w |= *dev->buf++ << 8;
 619                                 dev->buf_len--;
 620                         }
 621                         omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
 622                 } else
 623                         dev_err(dev->dev, "XRDY IRQ while no data to send\n");
 624                 break;
 625         default:
 626                 return IRQ_NONE;
 627         }
 628
 629         return IRQ_HANDLED;
 630 }
 631 #else
 632 #define omap_i2c_rev1_isr               NULL
 633 #endif
 634
 635 static irqreturn_t
 636 omap_i2c_isr(int this_irq, void *dev_id)
 637 {
 638         struct omap_i2c_dev *dev = dev_id;
 639         u16 bits;
 640         u16 stat, w;
 641         int err, count = 0;
 642
 643         if (dev->idle)
 644                 return IRQ_NONE;
 645
 646         bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
 647         while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
 648                 dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat);
 649                 if (count++ == 100) {
 650                         dev_warn(dev->dev, "Too much work in one IRQ\n");
 651                         break;
 652                 }
 653
 654                 omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
 655
 656                 err = 0;
 657                 if (stat & OMAP_I2C_STAT_NACK) {
 658                         err |= OMAP_I2C_STAT_NACK;
 659                         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
 660                                            OMAP_I2C_CON_STP);
 661                 }
 662                 if (stat & OMAP_I2C_STAT_AL) {
 663                         dev_err(dev->dev, "Arbitration lost\n");
 664                         err |= OMAP_I2C_STAT_AL;
 665                 }
 666                 if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |
 667                                         OMAP_I2C_STAT_AL))
 668                         omap_i2c_complete_cmd(dev, err);
 669                 if (stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR)) {
 670                         u8 num_bytes = 1;
 671                         if (dev->fifo_size) {
 672                                 if (stat & OMAP_I2C_STAT_RRDY)
 673                                         num_bytes = dev->fifo_size;
 674                                 else
 675                                         num_bytes = omap_i2c_read_reg(dev,
 676                                                         OMAP_I2C_BUFSTAT_REG);
 677                         }
 678                         while (num_bytes) {
 679                                 num_bytes--;
 680                                 w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
 681                                 if (dev->buf_len) {
 682                                         *dev->buf++ = w;
 683                                         dev->buf_len--;
 684                                         /* Data reg from 2430 is 8 bit wide */
 685                                         if (!cpu_is_omap2430() &&
 686                                                         !cpu_is_omap34xx()) {
 687                                                 if (dev->buf_len) {
 688                                                         *dev->buf++ = w >> 8;
 689                                                         dev->buf_len--;
 690                                                 }
 691                                         }
 692                                 } else {
 693                                         if (stat & OMAP_I2C_STAT_RRDY)
 694                                                 dev_err(dev->dev,
 695                                                         "RRDY IRQ while no data"
 696                                                                 " requested\n");
 697                                         if (stat & OMAP_I2C_STAT_RDR)
 698                                                 dev_err(dev->dev,
 699                                                         "RDR IRQ while no data"
 700                                                                 " requested\n");
 701                                         break;
 702                                 }
 703                         }
 704                         omap_i2c_ack_stat(dev,
 705                                 stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR));
 706                         continue;
 707                 }
 708                 if (stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR)) {
 709                         u8 num_bytes = 1;
 710                         if (dev->fifo_size) {
 711                                 if (stat & OMAP_I2C_STAT_XRDY)
 712                                         num_bytes = dev->fifo_size;
 713                                 else
 714                                         num_bytes = omap_i2c_read_reg(dev,
 715                                                         OMAP_I2C_BUFSTAT_REG);
 716                         }
 717                         while (num_bytes) {
 718                                 num_bytes--;
 719                                 w = 0;
 720                                 if (dev->buf_len) {
 721                                         w = *dev->buf++;
 722                                         dev->buf_len--;
 723                                         /* Data reg from  2430 is 8 bit wide */
 724                                         if (!cpu_is_omap2430() &&
 725                                                         !cpu_is_omap34xx()) {
 726                                                 if (dev->buf_len) {
 727                                                         w |= *dev->buf++ << 8;
 728                                                         dev->buf_len--;
 729                                                 }
 730                                         }
 731                                 } else {
 732                                         if (stat & OMAP_I2C_STAT_XRDY)
 733                                                 dev_err(dev->dev,
 734                                                         "XRDY IRQ while no "
 735                                                         "data to send\n");
 736                                         if (stat & OMAP_I2C_STAT_XDR)
 737                                                 dev_err(dev->dev,
 738                                                         "XDR IRQ while no "
 739                                                         "data to send\n");
 740                                         break;
 741                                 }
 742                                 omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
 743                         }
 744                         omap_i2c_ack_stat(dev,
 745                                 stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
 746                         continue;
 747                 }
 748                 if (stat & OMAP_I2C_STAT_ROVR) {
 749                         dev_err(dev->dev, "Receive overrun\n");
 750                         dev->cmd_err |= OMAP_I2C_STAT_ROVR;
 751                 }
 752                 if (stat & OMAP_I2C_STAT_XUDF) {
 753                         dev_err(dev->dev, "Transmit underflow\n");
 754                         dev->cmd_err |= OMAP_I2C_STAT_XUDF;
 755                 }
 756         }
 757
 758         return count ? IRQ_HANDLED : IRQ_NONE;
 759 }
 760
 761 static const struct i2c_algorithm omap_i2c_algo = {
 762         .master_xfer    = omap_i2c_xfer,
 763         .functionality  = omap_i2c_func,
 764 };
 765
 766 static int __init
 767 omap_i2c_probe(struct platform_device *pdev)
 768 {
 769         struct omap_i2c_dev     *dev;
 770         struct i2c_adapter      *adap;
 771         struct resource         *mem, *irq, *ioarea;
 772         irq_handler_t isr;
 773         int r;
 774         u32 speed = 0;
 775
 776         /* NOTE: driver uses the static register mapping */
 777         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 778         if (!mem) {
 779                 dev_err(&pdev->dev, "no mem resource?\n");
 780                 return -ENODEV;
 781         }
 782         irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 783         if (!irq) {
 784                 dev_err(&pdev->dev, "no irq resource?\n");
 785                 return -ENODEV;
 786         }
 787
 788         ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
 789                         pdev->name);
 790         if (!ioarea) {
 791                 dev_err(&pdev->dev, "I2C region already claimed\n");
 792                 return -EBUSY;
 793         }
 794
 795         dev = kzalloc(sizeof(struct omap_i2c_dev), GFP_KERNEL);
 796         if (!dev) {
 797                 r = -ENOMEM;
 798                 goto err_release_region;
 799         }
 800
 801         if (pdev->dev.platform_data != NULL)
 802                 speed = *(u32 *)pdev->dev.platform_data;
 803         else
 804                 speed = 100;    /* Defualt speed */
 805
 806         dev->speed = speed;
 807         dev->idle = 1;
 808         dev->dev = &pdev->dev;
 809         dev->irq = irq->start;
 810         dev->base = ioremap(mem->start, mem->end - mem->start + 1);
 811         if (!dev->base) {
 812                 r = -ENOMEM;
 813                 goto err_free_mem;
 814         }
 815
 816         platform_set_drvdata(pdev, dev);
 817
 818         if ((r = omap_i2c_get_clocks(dev)) != 0)
 819                 goto err_iounmap;
 820
 821         omap_i2c_unidle(dev);
 822
 823         dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
 824
 825         if (cpu_is_omap2430() || cpu_is_omap34xx()) {
 826                 u16 s;
 827
 828                 /* Set up the fifo size - Get total size */
 829                 s = (omap_i2c_read_reg(dev, OMAP_I2C_BUFSTAT_REG) >> 14) & 0x3;
 830                 dev->fifo_size = 0x8 << s;
 831
 832                 /*
 833                  * Set up notification threshold as half the total available
 834                  * size. This is to ensure that we can handle the status on int
 835                  * call back latencies.
 836                  */
 837                 dev->fifo_size = (dev->fifo_size / 2);
 838                 dev->b_hw = 1; /* Enable hardware fixes */
 839         }
 840
 841         /* reset ASAP, clearing any IRQs */
 842         omap_i2c_init(dev);
 843
 844         isr = (dev->rev < OMAP_I2C_REV_2) ? omap_i2c_rev1_isr : omap_i2c_isr;
 845         r = request_irq(dev->irq, isr, 0, pdev->name, dev);
 846
 847         if (r) {
 848                 dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
 849                 goto err_unuse_clocks;
 850         }
 851
 852         dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n",
 853                  pdev->id, dev->rev >> 4, dev->rev & 0xf, dev->speed);
 854
 855         omap_i2c_idle(dev);
 856
 857         adap = &dev->adapter;
 858         i2c_set_adapdata(adap, dev);
 859         adap->owner = THIS_MODULE;
 860         adap->class = I2C_CLASS_HWMON;
 861         strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
 862         adap->algo = &omap_i2c_algo;
 863         adap->dev.parent = &pdev->dev;
 864
 865         /* i2c device drivers may be active on return from add_adapter() */
 866         adap->nr = pdev->id;
 867         r = i2c_add_numbered_adapter(adap);
 868         if (r) {
 869                 dev_err(dev->dev, "failure adding adapter\n");
 870                 goto err_free_irq;
 871         }
 872
 873         return 0;
 874
 875 err_free_irq:
 876         free_irq(dev->irq, dev);
 877 err_unuse_clocks:
 878         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 879         omap_i2c_idle(dev);
 880         omap_i2c_put_clocks(dev);
 881 err_iounmap:
 882         iounmap(dev->base);
 883 err_free_mem:
 884         platform_set_drvdata(pdev, NULL);
 885         kfree(dev);
 886 err_release_region:
 887         release_mem_region(mem->start, (mem->end - mem->start) + 1);
 888
 889         return r;
 890 }
 891
 892 static int
 893 omap_i2c_remove(struct platform_device *pdev)
 894 {
 895         struct omap_i2c_dev     *dev = platform_get_drvdata(pdev);
 896         struct resource         *mem;
 897
 898         platform_set_drvdata(pdev, NULL);
 899
 900         free_irq(dev->irq, dev);
 901         i2c_del_adapter(&dev->adapter);
 902         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 903         omap_i2c_put_clocks(dev);
 904         iounmap(dev->base);
 905         kfree(dev);
 906         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 907         release_mem_region(mem->start, (mem->end - mem->start) + 1);
 908         return 0;
 909 }
 910
 911 static struct platform_driver omap_i2c_driver = {
 912         .probe          = omap_i2c_probe,
 913         .remove         = omap_i2c_remove,
 914         .driver         = {
 915                 .name   = "i2c_omap",
 916                 .owner  = THIS_MODULE,
 917         },
 918 };
 919
 920 /* I2C may be needed to bring up other drivers */
 921 static int __init
 922 omap_i2c_init_driver(void)
 923 {
 924         return platform_driver_register(&omap_i2c_driver);
 925 }
 926 subsys_initcall(omap_i2c_init_driver);
 927
 928 static void __exit omap_i2c_exit_driver(void)
 929 {
 930         platform_driver_unregister(&omap_i2c_driver);
 931 }
 932 module_exit(omap_i2c_exit_driver);
 933
 934 MODULE_AUTHOR("MontaVista Software, Inc. (and others)");
 935 MODULE_DESCRIPTION("TI OMAP I2C bus adapter");
 936 MODULE_LICENSE("GPL");
 937 MODULE_ALIAS("platform:i2c_omap");