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         if (cpu_is_omap16xx() || cpu_class_is_omap2()) {
 197                 dev->iclk = clk_get(dev->dev, "i2c_ick");
 198                 if (IS_ERR(dev->iclk)) {
 199                         dev->iclk = NULL;
 200                         return -ENODEV;
 201                 }
 202         }
 203
 204         dev->fclk = clk_get(dev->dev, "i2c_fck");
 205         if (IS_ERR(dev->fclk)) {
 206                 if (dev->iclk != NULL) {
 207                         clk_put(dev->iclk);
 208                         dev->iclk = NULL;
 209                 }
 210                 dev->fclk = NULL;
 211                 return -ENODEV;
 212         }
 213
 214         return 0;
 215 }
 216
 217 static void omap_i2c_put_clocks(struct omap_i2c_dev *dev)
 218 {
 219         clk_put(dev->fclk);
 220         dev->fclk = NULL;
 221         if (dev->iclk != NULL) {
 222                 clk_put(dev->iclk);
 223                 dev->iclk = NULL;
 224         }
 225 }
 226
 227 static void omap_i2c_unidle(struct omap_i2c_dev *dev)
 228 {
 229         WARN_ON(!dev->idle);
 230
 231         if (dev->iclk != NULL)
 232                 clk_enable(dev->iclk);
 233         clk_enable(dev->fclk);
 234         dev->idle = 0;
 235         if (dev->iestate)
 236                 omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
 237 }
 238
 239 static void omap_i2c_idle(struct omap_i2c_dev *dev)
 240 {
 241         u16 iv;
 242
 243         WARN_ON(dev->idle);
 244
 245         dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
 246         omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);
 247         if (dev->rev < OMAP_I2C_REV_2) {
 248                 iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); /* Read clears */
 249         } else {
 250                 omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate);
 251
 252                 /* Flush posted write before the dev->idle store occurs */
 253                 omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
 254         }
 255         dev->idle = 1;
 256         clk_disable(dev->fclk);
 257         if (dev->iclk != NULL)
 258                 clk_disable(dev->iclk);
 259 }
 260
 261 static int omap_i2c_init(struct omap_i2c_dev *dev)
 262 {
 263         u16 psc = 0, scll = 0, sclh = 0;
 264         u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
 265         unsigned long fclk_rate = 12000000;
 266         unsigned long timeout;
 267         unsigned long internal_clk = 0;
 268
 269         if (dev->rev >= OMAP_I2C_REV_2) {
 270                 omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, SYSC_SOFTRESET_MASK);
 271                 /* For some reason we need to set the EN bit before the
 272                  * reset done bit gets set. */
 273                 timeout = jiffies + OMAP_I2C_TIMEOUT;
 274                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
 275                 while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) &
 276                          SYSS_RESETDONE_MASK)) {
 277                         if (time_after(jiffies, timeout)) {
 278                                 dev_warn(dev->dev, "timeout waiting "
 279                                                 "for controller reset\n");
 280                                 return -ETIMEDOUT;
 281                         }
 282                         msleep(1);
 283                 }
 284
 285                 /* SYSC register is cleared by the reset; rewrite it */
 286                 if (dev->rev == OMAP_I2C_REV_ON_2430) {
 287
 288                         omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
 289                                            SYSC_AUTOIDLE_MASK);
 290
 291                 } else if (dev->rev >= OMAP_I2C_REV_ON_3430) {
 292                         u32 v;
 293
 294                         v = SYSC_AUTOIDLE_MASK;
 295                         v |= SYSC_ENAWAKEUP_MASK;
 296                         v |= (SYSC_IDLEMODE_SMART <<
 297                               __ffs(SYSC_SIDLEMODE_MASK));
 298                         v |= (SYSC_CLOCKACTIVITY_FCLK <<
 299                               __ffs(SYSC_CLOCKACTIVITY_MASK));
 300
 301                         omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, v);
 302                         /*
 303                          * Enabling all wakup sources to stop I2C freezing on
 304                          * WFI instruction.
 305                          * REVISIT: Some wkup sources might not be needed.
 306                          */
 307                         omap_i2c_write_reg(dev, OMAP_I2C_WE_REG,
 308                                                         OMAP_I2C_WE_ALL);
 309
 310                 }
 311         }
 312         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 313
 314         if (cpu_class_is_omap1()) {
 315                 struct clk *armxor_ck;
 316
 317                 armxor_ck = clk_get(NULL, "armxor_ck");
 318                 if (IS_ERR(armxor_ck))
 319                         dev_warn(dev->dev, "Could not get armxor_ck\n");
 320                 else {
 321                         fclk_rate = clk_get_rate(armxor_ck);
 322                         clk_put(armxor_ck);
 323                 }
 324                 /* TRM for 5912 says the I2C clock must be prescaled to be
 325                  * between 7 - 12 MHz. The XOR input clock is typically
 326                  * 12, 13 or 19.2 MHz. So we should have code that produces:
 327                  *
 328                  * XOR MHz      Divider         Prescaler
 329                  * 12           1               0
 330                  * 13           2               1
 331                  * 19.2         2               1
 332                  */
 333                 if (fclk_rate > 12000000)
 334                         psc = fclk_rate / 12000000;
 335         }
 336
 337         if (cpu_is_omap2430() || cpu_is_omap34xx()) {
 338
 339                 /* HSI2C controller internal clk rate should be 19.2 Mhz */
 340                 internal_clk = 19200;
 341                 fclk_rate = clk_get_rate(dev->fclk) / 1000;
 342
 343                 /* Compute prescaler divisor */
 344                 psc = fclk_rate / internal_clk;
 345                 psc = psc - 1;
 346
 347                 /* If configured for High Speed */
 348                 if (dev->speed > 400) {
 349                         /* For first phase of HS mode */
 350                         fsscll = internal_clk / (400 * 2) - 6;
 351                         fssclh = internal_clk / (400 * 2) - 6;
 352
 353                         /* For second phase of HS mode */
 354                         hsscll = fclk_rate / (dev->speed * 2) - 6;
 355                         hssclh = fclk_rate / (dev->speed * 2) - 6;
 356                 } else {
 357                         /* To handle F/S modes */
 358                         fsscll = internal_clk / (dev->speed * 2) - 6;
 359                         fssclh = internal_clk / (dev->speed * 2) - 6;
 360                 }
 361                 scll = (hsscll << OMAP_I2C_SCLL_HSSCLL) | fsscll;
 362                 sclh = (hssclh << OMAP_I2C_SCLH_HSSCLH) | fssclh;
 363         } else {
 364                 /* Program desired operating rate */
 365                 fclk_rate /= (psc + 1) * 1000;
 366                 if (psc > 2)
 367                         psc = 2;
 368                 scll = fclk_rate / (dev->speed * 2) - 7 + psc;
 369                 sclh = fclk_rate / (dev->speed * 2) - 7 + psc;
 370         }
 371
 372         /* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
 373         omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc);
 374
 375         /* SCL low and high time values */
 376         omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);
 377         omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);
 378
 379         if (dev->fifo_size)
 380                 /* Note: setup required fifo size - 1 */
 381                 omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG,
 382                                         (dev->fifo_size - 1) << 8 | /* RTRSH */
 383                                         OMAP_I2C_BUF_RXFIF_CLR |
 384                                         (dev->fifo_size - 1) | /* XTRSH */
 385                                         OMAP_I2C_BUF_TXFIF_CLR);
 386
 387         /* Take the I2C module out of reset: */
 388         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
 389
 390         /* Enable interrupts */
 391         omap_i2c_write_reg(dev, OMAP_I2C_IE_REG,
 392                         (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
 393                         OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |
 394                         OMAP_I2C_IE_AL)  | ((dev->fifo_size) ?
 395                                 (OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0));
 396         return 0;
 397 }
 398
 399 /*
 400  * Waiting on Bus Busy
 401  */
 402 static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev)
 403 {
 404         unsigned long timeout;
 405
 406         timeout = jiffies + OMAP_I2C_TIMEOUT;
 407         while (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) {
 408                 if (time_after(jiffies, timeout)) {
 409                         dev_warn(dev->dev, "timeout waiting for bus ready\n");
 410                         return -ETIMEDOUT;
 411                 }
 412                 msleep(1);
 413         }
 414
 415         return 0;
 416 }
 417
 418 /*
 419  * Low level master read/write transaction.
 420  */
 421 static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
 422                              struct i2c_msg *msg, int stop)
 423 {
 424         struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
 425         int r;
 426         u16 w;
 427
 428         dev_dbg(dev->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
 429                 msg->addr, msg->len, msg->flags, stop);
 430
 431         if (msg->len == 0)
 432                 return -EINVAL;
 433
 434         omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr);
 435
 436         /* REVISIT: Could the STB bit of I2C_CON be used with probing? */
 437         dev->buf = msg->buf;
 438         dev->buf_len = msg->len;
 439
 440         omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len);
 441
 442         /* Clear the FIFO Buffers */
 443         w = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG);
 444         w |= OMAP_I2C_BUF_RXFIF_CLR | OMAP_I2C_BUF_TXFIF_CLR;
 445         omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, w);
 446
 447         init_completion(&dev->cmd_complete);
 448         dev->cmd_err = 0;
 449
 450         w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
 451
 452         /* High speed configuration */
 453         if (dev->speed > 400)
 454                 w |= OMAP_I2C_CON_OPMODE_HS;
 455
 456         if (msg->flags & I2C_M_TEN)
 457                 w |= OMAP_I2C_CON_XA;
 458         if (!(msg->flags & I2C_M_RD))
 459                 w |= OMAP_I2C_CON_TRX;
 460
 461         if (!dev->b_hw && stop)
 462                 w |= OMAP_I2C_CON_STP;
 463
 464         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
 465
 466         /*
 467          * Don't write stt and stp together on some hardware.
 468          */
 469         if (dev->b_hw && stop) {
 470                 unsigned long delay = jiffies + OMAP_I2C_TIMEOUT;
 471                 u16 con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
 472                 while (con & OMAP_I2C_CON_STT) {
 473                         con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
 474
 475                         /* Let the user know if i2c is in a bad state */
 476                         if (time_after(jiffies, delay)) {
 477                                 dev_err(dev->dev, "controller timed out "
 478                                 "waiting for start condition to finish\n");
 479                                 return -ETIMEDOUT;
 480                         }
 481                         cpu_relax();
 482                 }
 483
 484                 w |= OMAP_I2C_CON_STP;
 485                 w &= ~OMAP_I2C_CON_STT;
 486                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
 487         }
 488
 489         /*
 490          * REVISIT: We should abort the transfer on signals, but the bus goes
 491          * into arbitration and we're currently unable to recover from it.
 492          */
 493         r = wait_for_completion_timeout(&dev->cmd_complete,
 494                                         OMAP_I2C_TIMEOUT);
 495         dev->buf_len = 0;
 496         if (r < 0)
 497                 return r;
 498         if (r == 0) {
 499                 dev_err(dev->dev, "controller timed out\n");
 500                 omap_i2c_init(dev);
 501                 return -ETIMEDOUT;
 502         }
 503
 504         if (likely(!dev->cmd_err))
 505                 return 0;
 506
 507         /* We have an error */
 508         if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
 509                             OMAP_I2C_STAT_XUDF)) {
 510                 omap_i2c_init(dev);
 511                 return -EIO;
 512         }
 513
 514         if (dev->cmd_err & OMAP_I2C_STAT_NACK) {
 515                 if (msg->flags & I2C_M_IGNORE_NAK)
 516                         return 0;
 517                 if (stop) {
 518                         w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
 519                         w |= OMAP_I2C_CON_STP;
 520                         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
 521                 }
 522                 return -EREMOTEIO;
 523         }
 524         return -EIO;
 525 }
 526
 527
 528 /*
 529  * Prepare controller for a transaction and call omap_i2c_xfer_msg
 530  * to do the work during IRQ processing.
 531  */
 532 static int
 533 omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 534 {
 535         struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
 536         int i;
 537         int r;
 538
 539         omap_i2c_unidle(dev);
 540
 541         r = omap_i2c_wait_for_bb(dev);
 542         if (r < 0)
 543                 goto out;
 544
 545         for (i = 0; i < num; i++) {
 546                 r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
 547                 if (r != 0)
 548                         break;
 549         }
 550
 551         if (r == 0)
 552                 r = num;
 553 out:
 554         omap_i2c_idle(dev);
 555         return r;
 556 }
 557
 558 static u32
 559 omap_i2c_func(struct i2c_adapter *adap)
 560 {
 561         return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
 562 }
 563
 564 static inline void
 565 omap_i2c_complete_cmd(struct omap_i2c_dev *dev, u16 err)
 566 {
 567         dev->cmd_err |= err;
 568         complete(&dev->cmd_complete);
 569 }
 570
 571 static inline void
 572 omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat)
 573 {
 574         omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
 575 }
 576
 577 /* rev1 devices are apparently only on some 15xx */
 578 #ifdef CONFIG_ARCH_OMAP15XX
 579
 580 static irqreturn_t
 581 omap_i2c_rev1_isr(int this_irq, void *dev_id)
 582 {
 583         struct omap_i2c_dev *dev = dev_id;
 584         u16 iv, w;
 585
 586         if (dev->idle)
 587                 return IRQ_NONE;
 588
 589         iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
 590         switch (iv) {
 591         case 0x00:      /* None */
 592                 break;
 593         case 0x01:      /* Arbitration lost */
 594                 dev_err(dev->dev, "Arbitration lost\n");
 595                 omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
 596                 break;
 597         case 0x02:      /* No acknowledgement */
 598                 omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
 599                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP);
 600                 break;
 601         case 0x03:      /* Register access ready */
 602                 omap_i2c_complete_cmd(dev, 0);
 603                 break;
 604         case 0x04:      /* Receive data ready */
 605                 if (dev->buf_len) {
 606                         w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
 607                         *dev->buf++ = w;
 608                         dev->buf_len--;
 609                         if (dev->buf_len) {
 610                                 *dev->buf++ = w >> 8;
 611                                 dev->buf_len--;
 612                         }
 613                 } else
 614                         dev_err(dev->dev, "RRDY IRQ while no data requested\n");
 615                 break;
 616         case 0x05:      /* Transmit data ready */
 617                 if (dev->buf_len) {
 618                         w = *dev->buf++;
 619                         dev->buf_len--;
 620                         if (dev->buf_len) {
 621                                 w |= *dev->buf++ << 8;
 622                                 dev->buf_len--;
 623                         }
 624                         omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
 625                 } else
 626                         dev_err(dev->dev, "XRDY IRQ while no data to send\n");
 627                 break;
 628         default:
 629                 return IRQ_NONE;
 630         }
 631
 632         return IRQ_HANDLED;
 633 }
 634 #else
 635 #define omap_i2c_rev1_isr               NULL
 636 #endif
 637
 638 static irqreturn_t
 639 omap_i2c_isr(int this_irq, void *dev_id)
 640 {
 641         struct omap_i2c_dev *dev = dev_id;
 642         u16 bits;
 643         u16 stat, w;
 644         int err, count = 0;
 645
 646         if (dev->idle)
 647                 return IRQ_NONE;
 648
 649         bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
 650         while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
 651                 dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat);
 652                 if (count++ == 100) {
 653                         dev_warn(dev->dev, "Too much work in one IRQ\n");
 654                         break;
 655                 }
 656
 657                 omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
 658
 659                 err = 0;
 660                 if (stat & OMAP_I2C_STAT_NACK) {
 661                         err |= OMAP_I2C_STAT_NACK;
 662                         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
 663                                            OMAP_I2C_CON_STP);
 664                 }
 665                 if (stat & OMAP_I2C_STAT_AL) {
 666                         dev_err(dev->dev, "Arbitration lost\n");
 667                         err |= OMAP_I2C_STAT_AL;
 668                 }
 669                 if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |
 670                                         OMAP_I2C_STAT_AL))
 671                         omap_i2c_complete_cmd(dev, err);
 672                 if (stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR)) {
 673                         u8 num_bytes = 1;
 674                         if (dev->fifo_size) {
 675                                 if (stat & OMAP_I2C_STAT_RRDY)
 676                                         num_bytes = dev->fifo_size;
 677                                 else
 678                                         num_bytes = omap_i2c_read_reg(dev,
 679                                                         OMAP_I2C_BUFSTAT_REG);
 680                         }
 681                         while (num_bytes) {
 682                                 num_bytes--;
 683                                 w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
 684                                 if (dev->buf_len) {
 685                                         *dev->buf++ = w;
 686                                         dev->buf_len--;
 687                                         /* Data reg from 2430 is 8 bit wide */
 688                                         if (!cpu_is_omap2430() &&
 689                                                         !cpu_is_omap34xx()) {
 690                                                 if (dev->buf_len) {
 691                                                         *dev->buf++ = w >> 8;
 692                                                         dev->buf_len--;
 693                                                 }
 694                                         }
 695                                 } else {
 696                                         if (stat & OMAP_I2C_STAT_RRDY)
 697                                                 dev_err(dev->dev,
 698                                                         "RRDY IRQ while no data"
 699                                                                 " requested\n");
 700                                         if (stat & OMAP_I2C_STAT_RDR)
 701                                                 dev_err(dev->dev,
 702                                                         "RDR IRQ while no data"
 703                                                                 " requested\n");
 704                                         break;
 705                                 }
 706                         }
 707                         omap_i2c_ack_stat(dev,
 708                                 stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR));
 709                         continue;
 710                 }
 711                 if (stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR)) {
 712                         u8 num_bytes = 1;
 713                         if (dev->fifo_size) {
 714                                 if (stat & OMAP_I2C_STAT_XRDY)
 715                                         num_bytes = dev->fifo_size;
 716                                 else
 717                                         num_bytes = omap_i2c_read_reg(dev,
 718                                                         OMAP_I2C_BUFSTAT_REG);
 719                         }
 720                         while (num_bytes) {
 721                                 num_bytes--;
 722                                 w = 0;
 723                                 if (dev->buf_len) {
 724                                         w = *dev->buf++;
 725                                         dev->buf_len--;
 726                                         /* Data reg from  2430 is 8 bit wide */
 727                                         if (!cpu_is_omap2430() &&
 728                                                         !cpu_is_omap34xx()) {
 729                                                 if (dev->buf_len) {
 730                                                         w |= *dev->buf++ << 8;
 731                                                         dev->buf_len--;
 732                                                 }
 733                                         }
 734                                 } else {
 735                                         if (stat & OMAP_I2C_STAT_XRDY)
 736                                                 dev_err(dev->dev,
 737                                                         "XRDY IRQ while no "
 738                                                         "data to send\n");
 739                                         if (stat & OMAP_I2C_STAT_XDR)
 740                                                 dev_err(dev->dev,
 741                                                         "XDR IRQ while no "
 742                                                         "data to send\n");
 743                                         break;
 744                                 }
 745                                 omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
 746                         }
 747                         omap_i2c_ack_stat(dev,
 748                                 stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
 749                         continue;
 750                 }
 751                 if (stat & OMAP_I2C_STAT_ROVR) {
 752                         dev_err(dev->dev, "Receive overrun\n");
 753                         dev->cmd_err |= OMAP_I2C_STAT_ROVR;
 754                 }
 755                 if (stat & OMAP_I2C_STAT_XUDF) {
 756                         dev_err(dev->dev, "Transmit underflow\n");
 757                         dev->cmd_err |= OMAP_I2C_STAT_XUDF;
 758                 }
 759         }
 760
 761         return count ? IRQ_HANDLED : IRQ_NONE;
 762 }
 763
 764 static const struct i2c_algorithm omap_i2c_algo = {
 765         .master_xfer    = omap_i2c_xfer,
 766         .functionality  = omap_i2c_func,
 767 };
 768
 769 static int __init
 770 omap_i2c_probe(struct platform_device *pdev)
 771 {
 772         struct omap_i2c_dev     *dev;
 773         struct i2c_adapter      *adap;
 774         struct resource         *mem, *irq, *ioarea;
 775         void *isr;
 776         int r;
 777         u32 speed = 0;
 778
 779         /* NOTE: driver uses the static register mapping */
 780         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 781         if (!mem) {
 782                 dev_err(&pdev->dev, "no mem resource?\n");
 783                 return -ENODEV;
 784         }
 785         irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 786         if (!irq) {
 787                 dev_err(&pdev->dev, "no irq resource?\n");
 788                 return -ENODEV;
 789         }
 790
 791         ioarea = request_mem_region(mem->start, (mem->end - mem->start) + 1,
 792                         pdev->name);
 793         if (!ioarea) {
 794                 dev_err(&pdev->dev, "I2C region already claimed\n");
 795                 return -EBUSY;
 796         }
 797
 798         dev = kzalloc(sizeof(struct omap_i2c_dev), GFP_KERNEL);
 799         if (!dev) {
 800                 r = -ENOMEM;
 801                 goto err_release_region;
 802         }
 803
 804         if (pdev->dev.platform_data != NULL)
 805                 speed = *(u32 *)pdev->dev.platform_data;
 806         else
 807                 speed = 100;    /* Defualt speed */
 808
 809         dev->speed = speed;
 810         dev->idle = 1;
 811         dev->dev = &pdev->dev;
 812         dev->irq = irq->start;
 813         dev->base = ioremap(mem->start, mem->end - mem->start + 1);
 814         if (!dev->base) {
 815                 r = -ENOMEM;
 816                 goto err_free_mem;
 817         }
 818
 819         platform_set_drvdata(pdev, dev);
 820
 821         if ((r = omap_i2c_get_clocks(dev)) != 0)
 822                 goto err_iounmap;
 823
 824         omap_i2c_unidle(dev);
 825
 826         dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
 827
 828         if (cpu_is_omap2430() || cpu_is_omap34xx()) {
 829                 u16 s;
 830
 831                 /* Set up the fifo size - Get total size */
 832                 s = (omap_i2c_read_reg(dev, OMAP_I2C_BUFSTAT_REG) >> 14) & 0x3;
 833                 dev->fifo_size = 0x8 << s;
 834
 835                 /*
 836                  * Set up notification threshold as half the total available
 837                  * size. This is to ensure that we can handle the status on int
 838                  * call back latencies.
 839                  */
 840                 dev->fifo_size = (dev->fifo_size / 2);
 841                 dev->b_hw = 1; /* Enable hardware fixes */
 842         }
 843
 844         /* reset ASAP, clearing any IRQs */
 845         omap_i2c_init(dev);
 846
 847         isr = (dev->rev < OMAP_I2C_REV_2) ? omap_i2c_rev1_isr : omap_i2c_isr;
 848         r = request_irq(dev->irq, isr, 0, pdev->name, dev);
 849
 850         if (r) {
 851                 dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
 852                 goto err_unuse_clocks;
 853         }
 854
 855         dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n",
 856                  pdev->id, dev->rev >> 4, dev->rev & 0xf, dev->speed);
 857
 858         omap_i2c_idle(dev);
 859
 860         adap = &dev->adapter;
 861         i2c_set_adapdata(adap, dev);
 862         adap->owner = THIS_MODULE;
 863         adap->class = I2C_CLASS_HWMON;
 864         strncpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
 865         adap->algo = &omap_i2c_algo;
 866         adap->dev.parent = &pdev->dev;
 867
 868         /* i2c device drivers may be active on return from add_adapter() */
 869         adap->nr = pdev->id;
 870         r = i2c_add_numbered_adapter(adap);
 871         if (r) {
 872                 dev_err(dev->dev, "failure adding adapter\n");
 873                 goto err_free_irq;
 874         }
 875
 876         return 0;
 877
 878 err_free_irq:
 879         free_irq(dev->irq, dev);
 880 err_unuse_clocks:
 881         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 882         omap_i2c_idle(dev);
 883         omap_i2c_put_clocks(dev);
 884 err_iounmap:
 885         iounmap(dev->base);
 886 err_free_mem:
 887         platform_set_drvdata(pdev, NULL);
 888         kfree(dev);
 889 err_release_region:
 890         release_mem_region(mem->start, (mem->end - mem->start) + 1);
 891
 892         return r;
 893 }
 894
 895 static int
 896 omap_i2c_remove(struct platform_device *pdev)
 897 {
 898         struct omap_i2c_dev     *dev = platform_get_drvdata(pdev);
 899         struct resource         *mem;
 900
 901         platform_set_drvdata(pdev, NULL);
 902
 903         free_irq(dev->irq, dev);
 904         i2c_del_adapter(&dev->adapter);
 905         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 906         omap_i2c_put_clocks(dev);
 907         iounmap(dev->base);
 908         kfree(dev);
 909         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 910         release_mem_region(mem->start, (mem->end - mem->start) + 1);
 911         return 0;
 912 }
 913
 914 static struct platform_driver omap_i2c_driver = {
 915         .probe          = omap_i2c_probe,
 916         .remove         = omap_i2c_remove,
 917         .driver         = {
 918                 .name   = "i2c_omap",
 919                 .owner  = THIS_MODULE,
 920         },
 921 };
 922
 923 /* I2C may be needed to bring up other drivers */
 924 static int __init
 925 omap_i2c_init_driver(void)
 926 {
 927         return platform_driver_register(&omap_i2c_driver);
 928 }
 929 subsys_initcall(omap_i2c_init_driver);
 930
 931 static void __exit omap_i2c_exit_driver(void)
 932 {
 933         platform_driver_unregister(&omap_i2c_driver);
 934 }
 935 module_exit(omap_i2c_exit_driver);
 936
 937 MODULE_AUTHOR("MontaVista Software, Inc. (and others)");
 938 MODULE_DESCRIPTION("TI OMAP I2C bus adapter");
 939 MODULE_LICENSE("GPL");
 940 MODULE_ALIAS("platform:i2c_omap");