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         u16                     pscstate;
 182         u16                     scllstate;
 183         u16                     sclhstate;
 184         u16                     bufstate;
 185         u16                     syscstate;
 186         u16                     westate;
 187 };
 188
 189 static inline void omap_i2c_write_reg(struct omap_i2c_dev *i2c_dev,
 190                                       int reg, u16 val)
 191 {
 192         __raw_writew(val, i2c_dev->base + reg);
 193 }
 194
 195 static inline u16 omap_i2c_read_reg(struct omap_i2c_dev *i2c_dev, int reg)
 196 {
 197         return __raw_readw(i2c_dev->base + reg);
 198 }
 199
 200 static int __init omap_i2c_get_clocks(struct omap_i2c_dev *dev)
 201 {
 202         int ret;
 203
 204         dev->iclk = clk_get(dev->dev, "ick");
 205         if (IS_ERR(dev->iclk)) {
 206                 ret = PTR_ERR(dev->iclk);
 207                 dev->iclk = NULL;
 208                 return ret;
 209         }
 210
 211         dev->fclk = clk_get(dev->dev, "fck");
 212         if (IS_ERR(dev->fclk)) {
 213                 ret = PTR_ERR(dev->fclk);
 214                 if (dev->iclk != NULL) {
 215                         clk_put(dev->iclk);
 216                         dev->iclk = NULL;
 217                 }
 218                 dev->fclk = NULL;
 219                 return ret;
 220         }
 221
 222         return 0;
 223 }
 224
 225 static void omap_i2c_put_clocks(struct omap_i2c_dev *dev)
 226 {
 227         clk_put(dev->fclk);
 228         dev->fclk = NULL;
 229         clk_put(dev->iclk);
 230         dev->iclk = NULL;
 231 }
 232
 233 static void omap_i2c_unidle(struct omap_i2c_dev *dev)
 234 {
 235         WARN_ON(!dev->idle);
 236
 237         clk_enable(dev->iclk);
 238         clk_enable(dev->fclk);
 239         if (cpu_is_omap34xx()) {
 240                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 241                 omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, dev->pscstate);
 242                 omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, dev->scllstate);
 243                 omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, dev->sclhstate);
 244                 omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, dev->bufstate);
 245                 omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, dev->syscstate);
 246                 omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, dev->westate);
 247                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
 248         }
 249         dev->idle = 0;
 250
 251         /*
 252          * Don't write to this register if the IE state is 0 as it can
 253          * cause deadlock.
 254          */
 255         if (dev->iestate)
 256                 omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
 257 }
 258
 259 static void omap_i2c_idle(struct omap_i2c_dev *dev)
 260 {
 261         u16 iv;
 262
 263         WARN_ON(dev->idle);
 264
 265         dev->iestate = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
 266         omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, 0);
 267         if (dev->rev < OMAP_I2C_REV_2) {
 268                 iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG); /* Read clears */
 269         } else {
 270                 omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, dev->iestate);
 271
 272                 /* Flush posted write before the dev->idle store occurs */
 273                 omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
 274         }
 275         dev->idle = 1;
 276         clk_disable(dev->fclk);
 277         clk_disable(dev->iclk);
 278 }
 279
 280 static int omap_i2c_init(struct omap_i2c_dev *dev)
 281 {
 282         u16 psc = 0, scll = 0, sclh = 0, buf = 0;
 283         u16 fsscll = 0, fssclh = 0, hsscll = 0, hssclh = 0;
 284         unsigned long fclk_rate = 12000000;
 285         unsigned long timeout;
 286         unsigned long internal_clk = 0;
 287
 288         if (dev->rev >= OMAP_I2C_REV_2) {
 289                 omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG, SYSC_SOFTRESET_MASK);
 290                 /* For some reason we need to set the EN bit before the
 291                  * reset done bit gets set. */
 292                 timeout = jiffies + OMAP_I2C_TIMEOUT;
 293                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
 294                 while (!(omap_i2c_read_reg(dev, OMAP_I2C_SYSS_REG) &
 295                          SYSS_RESETDONE_MASK)) {
 296                         if (time_after(jiffies, timeout)) {
 297                                 dev_warn(dev->dev, "timeout waiting "
 298                                                 "for controller reset\n");
 299                                 return -ETIMEDOUT;
 300                         }
 301                         msleep(1);
 302                 }
 303
 304                 /* SYSC register is cleared by the reset; rewrite it */
 305                 if (dev->rev == OMAP_I2C_REV_ON_2430) {
 306
 307                         omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
 308                                            SYSC_AUTOIDLE_MASK);
 309
 310                 } else if (dev->rev >= OMAP_I2C_REV_ON_3430) {
 311                         dev->syscstate = SYSC_AUTOIDLE_MASK;
 312                         dev->syscstate |= SYSC_ENAWAKEUP_MASK;
 313                         dev->syscstate |= (SYSC_IDLEMODE_SMART <<
 314                               __ffs(SYSC_SIDLEMODE_MASK));
 315                         dev->syscstate |= (SYSC_CLOCKACTIVITY_FCLK <<
 316                               __ffs(SYSC_CLOCKACTIVITY_MASK));
 317
 318                         omap_i2c_write_reg(dev, OMAP_I2C_SYSC_REG,
 319                                                         dev->syscstate);
 320                         /*
 321                          * Enabling all wakup sources to stop I2C freezing on
 322                          * WFI instruction.
 323                          * REVISIT: Some wkup sources might not be needed.
 324                          */
 325                         dev->westate = OMAP_I2C_WE_ALL;
 326                         omap_i2c_write_reg(dev, OMAP_I2C_WE_REG, dev->westate);
 327                 }
 328         }
 329         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 330
 331         if (cpu_class_is_omap1()) {
 332                 /*
 333                  * The I2C functional clock is the armxor_ck, so there's
 334                  * no need to get "armxor_ck" separately.  Now, if OMAP2420
 335                  * always returns 12MHz for the functional clock, we can
 336                  * do this bit unconditionally.
 337                  */
 338                 fclk_rate = clk_get_rate(dev->fclk);
 339
 340                 /* TRM for 5912 says the I2C clock must be prescaled to be
 341                  * between 7 - 12 MHz. The XOR input clock is typically
 342                  * 12, 13 or 19.2 MHz. So we should have code that produces:
 343                  *
 344                  * XOR MHz      Divider         Prescaler
 345                  * 12           1               0
 346                  * 13           2               1
 347                  * 19.2         2               1
 348                  */
 349                 if (fclk_rate > 12000000)
 350                         psc = fclk_rate / 12000000;
 351         }
 352
 353         if (cpu_is_omap2430() || cpu_is_omap34xx()) {
 354
 355                 /*
 356                  * HSI2C controller internal clk rate should be 19.2 Mhz for
 357                  * HS and for all modes on 2430. On 34xx we can use lower rate
 358                  * to get longer filter period for better noise suppression.
 359                  * The filter is iclk (fclk for HS) period.
 360                  */
 361                 if (dev->speed > 400 || cpu_is_omap2430())
 362                         internal_clk = 19200;
 363                 else if (dev->speed > 100)
 364                         internal_clk = 9600;
 365                 else
 366                         internal_clk = 4000;
 367                 fclk_rate = clk_get_rate(dev->fclk) / 1000;
 368
 369                 /* Compute prescaler divisor */
 370                 psc = fclk_rate / internal_clk;
 371                 psc = psc - 1;
 372
 373                 /* If configured for High Speed */
 374                 if (dev->speed > 400) {
 375                         unsigned long scl;
 376
 377                         /* For first phase of HS mode */
 378                         scl = internal_clk / 400;
 379                         fsscll = scl - (scl / 3) - 7;
 380                         fssclh = (scl / 3) - 5;
 381
 382                         /* For second phase of HS mode */
 383                         scl = fclk_rate / dev->speed;
 384                         hsscll = scl - (scl / 3) - 7;
 385                         hssclh = (scl / 3) - 5;
 386                 } else if (dev->speed > 100) {
 387                         unsigned long scl;
 388
 389                         /* Fast mode */
 390                         scl = internal_clk / dev->speed;
 391                         fsscll = scl - (scl / 3) - 7;
 392                         fssclh = (scl / 3) - 5;
 393                 } else {
 394                         /* Standard mode */
 395                         fsscll = internal_clk / (dev->speed * 2) - 7;
 396                         fssclh = internal_clk / (dev->speed * 2) - 5;
 397                 }
 398                 scll = (hsscll << OMAP_I2C_SCLL_HSSCLL) | fsscll;
 399                 sclh = (hssclh << OMAP_I2C_SCLH_HSSCLH) | fssclh;
 400         } else {
 401                 /* Program desired operating rate */
 402                 fclk_rate /= (psc + 1) * 1000;
 403                 if (psc > 2)
 404                         psc = 2;
 405                 scll = fclk_rate / (dev->speed * 2) - 7 + psc;
 406                 sclh = fclk_rate / (dev->speed * 2) - 7 + psc;
 407         }
 408
 409         /* Setup clock prescaler to obtain approx 12MHz I2C module clock: */
 410         omap_i2c_write_reg(dev, OMAP_I2C_PSC_REG, psc);
 411
 412         /* SCL low and high time values */
 413         omap_i2c_write_reg(dev, OMAP_I2C_SCLL_REG, scll);
 414         omap_i2c_write_reg(dev, OMAP_I2C_SCLH_REG, sclh);
 415
 416         if (dev->fifo_size) {
 417                 /* Note: setup required fifo size - 1. RTRSH and XTRSH */
 418                 buf = (dev->fifo_size - 1) << 8 | OMAP_I2C_BUF_RXFIF_CLR |
 419                         (dev->fifo_size - 1) | OMAP_I2C_BUF_TXFIF_CLR;
 420                 omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, buf);
 421         }
 422
 423         /* Take the I2C module out of reset: */
 424         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_EN);
 425
 426         /* Enable interrupts */
 427         dev->iestate = (OMAP_I2C_IE_XRDY | OMAP_I2C_IE_RRDY |
 428                         OMAP_I2C_IE_ARDY | OMAP_I2C_IE_NACK |
 429                         OMAP_I2C_IE_AL)  | ((dev->fifo_size) ?
 430                                 (OMAP_I2C_IE_RDR | OMAP_I2C_IE_XDR) : 0);
 431         omap_i2c_write_reg(dev, OMAP_I2C_IE_REG, dev->iestate);
 432         if (cpu_is_omap34xx()) {
 433                 dev->pscstate = psc;
 434                 dev->scllstate = scll;
 435                 dev->sclhstate = sclh;
 436                 dev->bufstate = buf;
 437         }
 438         return 0;
 439 }
 440
 441 /*
 442  * Waiting on Bus Busy
 443  */
 444 static int omap_i2c_wait_for_bb(struct omap_i2c_dev *dev)
 445 {
 446         unsigned long timeout;
 447
 448         timeout = jiffies + OMAP_I2C_TIMEOUT;
 449         while (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG) & OMAP_I2C_STAT_BB) {
 450                 if (time_after(jiffies, timeout)) {
 451                         dev_warn(dev->dev, "timeout waiting for bus ready\n");
 452                         return -ETIMEDOUT;
 453                 }
 454                 msleep(1);
 455         }
 456
 457         return 0;
 458 }
 459
 460 /*
 461  * Low level master read/write transaction.
 462  */
 463 static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
 464                              struct i2c_msg *msg, int stop)
 465 {
 466         struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
 467         int r;
 468         u16 w;
 469
 470         dev_dbg(dev->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
 471                 msg->addr, msg->len, msg->flags, stop);
 472
 473         if (msg->len == 0)
 474                 return -EINVAL;
 475
 476         omap_i2c_write_reg(dev, OMAP_I2C_SA_REG, msg->addr);
 477
 478         /* REVISIT: Could the STB bit of I2C_CON be used with probing? */
 479         dev->buf = msg->buf;
 480         dev->buf_len = msg->len;
 481
 482         omap_i2c_write_reg(dev, OMAP_I2C_CNT_REG, dev->buf_len);
 483
 484         /* Clear the FIFO Buffers */
 485         w = omap_i2c_read_reg(dev, OMAP_I2C_BUF_REG);
 486         w |= OMAP_I2C_BUF_RXFIF_CLR | OMAP_I2C_BUF_TXFIF_CLR;
 487         omap_i2c_write_reg(dev, OMAP_I2C_BUF_REG, w);
 488
 489         init_completion(&dev->cmd_complete);
 490         dev->cmd_err = 0;
 491
 492         w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
 493
 494         /* High speed configuration */
 495         if (dev->speed > 400)
 496                 w |= OMAP_I2C_CON_OPMODE_HS;
 497
 498         if (msg->flags & I2C_M_TEN)
 499                 w |= OMAP_I2C_CON_XA;
 500         if (!(msg->flags & I2C_M_RD))
 501                 w |= OMAP_I2C_CON_TRX;
 502
 503         if (!dev->b_hw && stop)
 504                 w |= OMAP_I2C_CON_STP;
 505
 506         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
 507
 508         /*
 509          * Don't write stt and stp together on some hardware.
 510          */
 511         if (dev->b_hw && stop) {
 512                 unsigned long delay = jiffies + OMAP_I2C_TIMEOUT;
 513                 u16 con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
 514                 while (con & OMAP_I2C_CON_STT) {
 515                         con = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
 516
 517                         /* Let the user know if i2c is in a bad state */
 518                         if (time_after(jiffies, delay)) {
 519                                 dev_err(dev->dev, "controller timed out "
 520                                 "waiting for start condition to finish\n");
 521                                 return -ETIMEDOUT;
 522                         }
 523                         cpu_relax();
 524                 }
 525
 526                 w |= OMAP_I2C_CON_STP;
 527                 w &= ~OMAP_I2C_CON_STT;
 528                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
 529         }
 530
 531         /*
 532          * REVISIT: We should abort the transfer on signals, but the bus goes
 533          * into arbitration and we're currently unable to recover from it.
 534          */
 535         r = wait_for_completion_timeout(&dev->cmd_complete,
 536                                         OMAP_I2C_TIMEOUT);
 537         dev->buf_len = 0;
 538         if (r < 0)
 539                 return r;
 540         if (r == 0) {
 541                 dev_err(dev->dev, "controller timed out\n");
 542                 omap_i2c_init(dev);
 543                 return -ETIMEDOUT;
 544         }
 545
 546         if (likely(!dev->cmd_err))
 547                 return 0;
 548
 549         /* We have an error */
 550         if (dev->cmd_err & (OMAP_I2C_STAT_AL | OMAP_I2C_STAT_ROVR |
 551                             OMAP_I2C_STAT_XUDF)) {
 552                 omap_i2c_init(dev);
 553                 return -EIO;
 554         }
 555
 556         if (dev->cmd_err & OMAP_I2C_STAT_NACK) {
 557                 if (msg->flags & I2C_M_IGNORE_NAK)
 558                         return 0;
 559                 if (stop) {
 560                         w = omap_i2c_read_reg(dev, OMAP_I2C_CON_REG);
 561                         w |= OMAP_I2C_CON_STP;
 562                         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, w);
 563                 }
 564                 return -EREMOTEIO;
 565         }
 566         return -EIO;
 567 }
 568
 569
 570 /*
 571  * Prepare controller for a transaction and call omap_i2c_xfer_msg
 572  * to do the work during IRQ processing.
 573  */
 574 static int
 575 omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 576 {
 577         struct omap_i2c_dev *dev = i2c_get_adapdata(adap);
 578         int i;
 579         int r;
 580
 581         omap_i2c_unidle(dev);
 582
 583         r = omap_i2c_wait_for_bb(dev);
 584         if (r < 0)
 585                 goto out;
 586
 587         for (i = 0; i < num; i++) {
 588                 r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
 589                 if (r != 0)
 590                         break;
 591         }
 592
 593         if (r == 0)
 594                 r = num;
 595 out:
 596         omap_i2c_idle(dev);
 597         return r;
 598 }
 599
 600 static u32
 601 omap_i2c_func(struct i2c_adapter *adap)
 602 {
 603         return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
 604 }
 605
 606 static inline void
 607 omap_i2c_complete_cmd(struct omap_i2c_dev *dev, u16 err)
 608 {
 609         dev->cmd_err |= err;
 610         complete(&dev->cmd_complete);
 611 }
 612
 613 static inline void
 614 omap_i2c_ack_stat(struct omap_i2c_dev *dev, u16 stat)
 615 {
 616         omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat);
 617 }
 618
 619 /* rev1 devices are apparently only on some 15xx */
 620 #ifdef CONFIG_ARCH_OMAP15XX
 621
 622 static irqreturn_t
 623 omap_i2c_rev1_isr(int this_irq, void *dev_id)
 624 {
 625         struct omap_i2c_dev *dev = dev_id;
 626         u16 iv, w;
 627
 628         if (dev->idle)
 629                 return IRQ_NONE;
 630
 631         iv = omap_i2c_read_reg(dev, OMAP_I2C_IV_REG);
 632         switch (iv) {
 633         case 0x00:      /* None */
 634                 break;
 635         case 0x01:      /* Arbitration lost */
 636                 dev_err(dev->dev, "Arbitration lost\n");
 637                 omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_AL);
 638                 break;
 639         case 0x02:      /* No acknowledgement */
 640                 omap_i2c_complete_cmd(dev, OMAP_I2C_STAT_NACK);
 641                 omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, OMAP_I2C_CON_STP);
 642                 break;
 643         case 0x03:      /* Register access ready */
 644                 omap_i2c_complete_cmd(dev, 0);
 645                 break;
 646         case 0x04:      /* Receive data ready */
 647                 if (dev->buf_len) {
 648                         w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
 649                         *dev->buf++ = w;
 650                         dev->buf_len--;
 651                         if (dev->buf_len) {
 652                                 *dev->buf++ = w >> 8;
 653                                 dev->buf_len--;
 654                         }
 655                 } else
 656                         dev_err(dev->dev, "RRDY IRQ while no data requested\n");
 657                 break;
 658         case 0x05:      /* Transmit data ready */
 659                 if (dev->buf_len) {
 660                         w = *dev->buf++;
 661                         dev->buf_len--;
 662                         if (dev->buf_len) {
 663                                 w |= *dev->buf++ << 8;
 664                                 dev->buf_len--;
 665                         }
 666                         omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
 667                 } else
 668                         dev_err(dev->dev, "XRDY IRQ while no data to send\n");
 669                 break;
 670         default:
 671                 return IRQ_NONE;
 672         }
 673
 674         return IRQ_HANDLED;
 675 }
 676 #else
 677 #define omap_i2c_rev1_isr               NULL
 678 #endif
 679
 680 static irqreturn_t
 681 omap_i2c_isr(int this_irq, void *dev_id)
 682 {
 683         struct omap_i2c_dev *dev = dev_id;
 684         u16 bits;
 685         u16 stat, w;
 686         int err, count = 0;
 687
 688         if (dev->idle)
 689                 return IRQ_NONE;
 690
 691         bits = omap_i2c_read_reg(dev, OMAP_I2C_IE_REG);
 692         while ((stat = (omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG))) & bits) {
 693                 dev_dbg(dev->dev, "IRQ (ISR = 0x%04x)\n", stat);
 694                 if (count++ == 100) {
 695                         dev_warn(dev->dev, "Too much work in one IRQ\n");
 696                         break;
 697                 }
 698
 699                 err = 0;
 700 complete:
 701                 /*
 702                  * Ack the stat in one go, but [R/X]DR and [R/X]RDY should be
 703                  * acked after the data operation is complete.
 704                  * Ref: TRM SWPU114Q Figure 18-31
 705                  */
 706                 omap_i2c_write_reg(dev, OMAP_I2C_STAT_REG, stat &
 707                                 ~(OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
 708                                 OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
 709
 710                 if (stat & OMAP_I2C_STAT_NACK) {
 711                         err |= OMAP_I2C_STAT_NACK;
 712                         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
 713                                            OMAP_I2C_CON_STP);
 714                 }
 715                 if (stat & OMAP_I2C_STAT_AL) {
 716                         dev_err(dev->dev, "Arbitration lost\n");
 717                         err |= OMAP_I2C_STAT_AL;
 718                 }
 719                 if (stat & (OMAP_I2C_STAT_ARDY | OMAP_I2C_STAT_NACK |
 720                                         OMAP_I2C_STAT_AL)) {
 721                         omap_i2c_ack_stat(dev, stat &
 722                                 (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
 723                                 OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
 724                         omap_i2c_complete_cmd(dev, err);
 725                         return IRQ_HANDLED;
 726                 }
 727                 if (stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR)) {
 728                         u8 num_bytes = 1;
 729                         if (dev->fifo_size) {
 730                                 if (stat & OMAP_I2C_STAT_RRDY)
 731                                         num_bytes = dev->fifo_size;
 732                                 else    /* read RXSTAT on RDR interrupt */
 733                                         num_bytes = (omap_i2c_read_reg(dev,
 734                                                         OMAP_I2C_BUFSTAT_REG)
 735                                                         >> 8) & 0x3F;
 736                         }
 737                         while (num_bytes) {
 738                                 num_bytes--;
 739                                 w = omap_i2c_read_reg(dev, OMAP_I2C_DATA_REG);
 740                                 if (dev->buf_len) {
 741                                         *dev->buf++ = w;
 742                                         dev->buf_len--;
 743                                         /* Data reg from 2430 is 8 bit wide */
 744                                         if (!cpu_is_omap2430() &&
 745                                                         !cpu_is_omap34xx()) {
 746                                                 if (dev->buf_len) {
 747                                                         *dev->buf++ = w >> 8;
 748                                                         dev->buf_len--;
 749                                                 }
 750                                         }
 751                                 } else {
 752                                         if (stat & OMAP_I2C_STAT_RRDY)
 753                                                 dev_err(dev->dev,
 754                                                         "RRDY IRQ while no data"
 755                                                                 " requested\n");
 756                                         if (stat & OMAP_I2C_STAT_RDR)
 757                                                 dev_err(dev->dev,
 758                                                         "RDR IRQ while no data"
 759                                                                 " requested\n");
 760                                         break;
 761                                 }
 762                         }
 763                         omap_i2c_ack_stat(dev,
 764                                 stat & (OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR));
 765                         continue;
 766                 }
 767                 if (stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR)) {
 768                         u8 num_bytes = 1;
 769                         if (dev->fifo_size) {
 770                                 if (stat & OMAP_I2C_STAT_XRDY)
 771                                         num_bytes = dev->fifo_size;
 772                                 else    /* read TXSTAT on XDR interrupt */
 773                                         num_bytes = omap_i2c_read_reg(dev,
 774                                                         OMAP_I2C_BUFSTAT_REG)
 775                                                         & 0x3F;
 776                         }
 777                         while (num_bytes) {
 778                                 num_bytes--;
 779                                 w = 0;
 780                                 if (dev->buf_len) {
 781                                         w = *dev->buf++;
 782                                         dev->buf_len--;
 783                                         /* Data reg from  2430 is 8 bit wide */
 784                                         if (!cpu_is_omap2430() &&
 785                                                         !cpu_is_omap34xx()) {
 786                                                 if (dev->buf_len) {
 787                                                         w |= *dev->buf++ << 8;
 788                                                         dev->buf_len--;
 789                                                 }
 790                                         }
 791                                 } else {
 792                                         if (stat & OMAP_I2C_STAT_XRDY)
 793                                                 dev_err(dev->dev,
 794                                                         "XRDY IRQ while no "
 795                                                         "data to send\n");
 796                                         if (stat & OMAP_I2C_STAT_XDR)
 797                                                 dev_err(dev->dev,
 798                                                         "XDR IRQ while no "
 799                                                         "data to send\n");
 800                                         break;
 801                                 }
 802
 803                                 /*
 804                                  * OMAP3430 Errata 1.153: When an XRDY/XDR
 805                                  * is hit, wait for XUDF before writing data
 806                                  * to DATA_REG. Otherwise some data bytes can
 807                                  * be lost while transferring them from the
 808                                  * memory to the I2C interface.
 809                                  */
 810
 811                                 if (dev->rev <= OMAP_I2C_REV_ON_3430) {
 812                                                 while (!(stat & OMAP_I2C_STAT_XUDF)) {
 813                                                         if (stat & (OMAP_I2C_STAT_NACK | OMAP_I2C_STAT_AL)) {
 814                                                                 omap_i2c_ack_stat(dev, stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
 815                                                                 err |= OMAP_I2C_STAT_XUDF;
 816                                                                 goto complete;
 817                                                         }
 818                                                         cpu_relax();
 819                                                         stat = omap_i2c_read_reg(dev, OMAP_I2C_STAT_REG);
 820                                                 }
 821                                 }
 822
 823                                 omap_i2c_write_reg(dev, OMAP_I2C_DATA_REG, w);
 824                         }
 825                         omap_i2c_ack_stat(dev,
 826                                 stat & (OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
 827                         continue;
 828                 }
 829                 if (stat & OMAP_I2C_STAT_ROVR) {
 830                         dev_err(dev->dev, "Receive overrun\n");
 831                         dev->cmd_err |= OMAP_I2C_STAT_ROVR;
 832                 }
 833                 if (stat & OMAP_I2C_STAT_XUDF) {
 834                         dev_err(dev->dev, "Transmit underflow\n");
 835                         dev->cmd_err |= OMAP_I2C_STAT_XUDF;
 836                 }
 837         }
 838
 839         return count ? IRQ_HANDLED : IRQ_NONE;
 840 }
 841
 842 static const struct i2c_algorithm omap_i2c_algo = {
 843         .master_xfer    = omap_i2c_xfer,
 844         .functionality  = omap_i2c_func,
 845 };
 846
 847 static int __init
 848 omap_i2c_probe(struct platform_device *pdev)
 849 {
 850         struct omap_i2c_dev     *dev;
 851         struct i2c_adapter      *adap;
 852         struct resource         *mem, *irq, *ioarea;
 853         irq_handler_t isr;
 854         int r;
 855         u32 speed = 0;
 856
 857         /* NOTE: driver uses the static register mapping */
 858         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 859         if (!mem) {
 860                 dev_err(&pdev->dev, "no mem resource?\n");
 861                 return -ENODEV;
 862         }
 863         irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 864         if (!irq) {
 865                 dev_err(&pdev->dev, "no irq resource?\n");
 866                 return -ENODEV;
 867         }
 868
 869         ioarea = request_mem_region(mem->start, resource_size(mem),
 870                         pdev->name);
 871         if (!ioarea) {
 872                 dev_err(&pdev->dev, "I2C region already claimed\n");
 873                 return -EBUSY;
 874         }
 875
 876         dev = kzalloc(sizeof(struct omap_i2c_dev), GFP_KERNEL);
 877         if (!dev) {
 878                 r = -ENOMEM;
 879                 goto err_release_region;
 880         }
 881
 882         if (pdev->dev.platform_data != NULL)
 883                 speed = *(u32 *)pdev->dev.platform_data;
 884         else
 885                 speed = 100;    /* Defualt speed */
 886
 887         dev->speed = speed;
 888         dev->idle = 1;
 889         dev->dev = &pdev->dev;
 890         dev->irq = irq->start;
 891         dev->base = ioremap(mem->start, resource_size(mem));
 892         if (!dev->base) {
 893                 r = -ENOMEM;
 894                 goto err_free_mem;
 895         }
 896
 897         platform_set_drvdata(pdev, dev);
 898
 899         if ((r = omap_i2c_get_clocks(dev)) != 0)
 900                 goto err_iounmap;
 901
 902         omap_i2c_unidle(dev);
 903
 904         dev->rev = omap_i2c_read_reg(dev, OMAP_I2C_REV_REG) & 0xff;
 905
 906         if (cpu_is_omap2430() || cpu_is_omap34xx()) {
 907                 u16 s;
 908
 909                 /* Set up the fifo size - Get total size */
 910                 s = (omap_i2c_read_reg(dev, OMAP_I2C_BUFSTAT_REG) >> 14) & 0x3;
 911                 dev->fifo_size = 0x8 << s;
 912
 913                 /*
 914                  * Set up notification threshold as half the total available
 915                  * size. This is to ensure that we can handle the status on int
 916                  * call back latencies.
 917                  */
 918                 dev->fifo_size = (dev->fifo_size / 2);
 919                 dev->b_hw = 1; /* Enable hardware fixes */
 920         }
 921
 922         /* reset ASAP, clearing any IRQs */
 923         omap_i2c_init(dev);
 924
 925         isr = (dev->rev < OMAP_I2C_REV_2) ? omap_i2c_rev1_isr : omap_i2c_isr;
 926         r = request_irq(dev->irq, isr, 0, pdev->name, dev);
 927
 928         if (r) {
 929                 dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
 930                 goto err_unuse_clocks;
 931         }
 932
 933         dev_info(dev->dev, "bus %d rev%d.%d at %d kHz\n",
 934                  pdev->id, dev->rev >> 4, dev->rev & 0xf, dev->speed);
 935
 936         omap_i2c_idle(dev);
 937
 938         adap = &dev->adapter;
 939         i2c_set_adapdata(adap, dev);
 940         adap->owner = THIS_MODULE;
 941         adap->class = I2C_CLASS_HWMON;
 942         strlcpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
 943         adap->algo = &omap_i2c_algo;
 944         adap->dev.parent = &pdev->dev;
 945
 946         /* i2c device drivers may be active on return from add_adapter() */
 947         adap->nr = pdev->id;
 948         r = i2c_add_numbered_adapter(adap);
 949         if (r) {
 950                 dev_err(dev->dev, "failure adding adapter\n");
 951                 goto err_free_irq;
 952         }
 953
 954         return 0;
 955
 956 err_free_irq:
 957         free_irq(dev->irq, dev);
 958 err_unuse_clocks:
 959         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 960         omap_i2c_idle(dev);
 961         omap_i2c_put_clocks(dev);
 962 err_iounmap:
 963         iounmap(dev->base);
 964 err_free_mem:
 965         platform_set_drvdata(pdev, NULL);
 966         kfree(dev);
 967 err_release_region:
 968         release_mem_region(mem->start, resource_size(mem));
 969
 970         return r;
 971 }
 972
 973 static int
 974 omap_i2c_remove(struct platform_device *pdev)
 975 {
 976         struct omap_i2c_dev     *dev = platform_get_drvdata(pdev);
 977         struct resource         *mem;
 978
 979         platform_set_drvdata(pdev, NULL);
 980
 981         free_irq(dev->irq, dev);
 982         i2c_del_adapter(&dev->adapter);
 983         omap_i2c_write_reg(dev, OMAP_I2C_CON_REG, 0);
 984         omap_i2c_put_clocks(dev);
 985         iounmap(dev->base);
 986         kfree(dev);
 987         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 988         release_mem_region(mem->start, resource_size(mem));
 989         return 0;
 990 }
 991
 992 static struct platform_driver omap_i2c_driver = {
 993         .probe          = omap_i2c_probe,
 994         .remove         = omap_i2c_remove,
 995         .driver         = {
 996                 .name   = "i2c_omap",
 997                 .owner  = THIS_MODULE,
 998         },
 999 };
1000
1001 /* I2C may be needed to bring up other drivers */
1002 static int __init
1003 omap_i2c_init_driver(void)
1004 {
1005         return platform_driver_register(&omap_i2c_driver);
1006 }
1007 subsys_initcall(omap_i2c_init_driver);
1008
1009 static void __exit omap_i2c_exit_driver(void)
1010 {
1011         platform_driver_unregister(&omap_i2c_driver);
1012 }
1013 module_exit(omap_i2c_exit_driver);
1014
1015 MODULE_AUTHOR("MontaVista Software, Inc. (and others)");
1016 MODULE_DESCRIPTION("TI OMAP I2C bus adapter");
1017 MODULE_LICENSE("GPL");
1018 MODULE_ALIAS("platform:i2c_omap");