cpu/blackfin/i2c.c

   1 /*
   2  * i2c.c - driver for Blackfin on-chip TWI/I2C
   3  *
   4  * Copyright (c) 2006-2008 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <common.h>
  10
  11 #ifdef CONFIG_HARD_I2C
  12
  13 #include <asm/blackfin.h>
  14 #include <i2c.h>
  15 #include <asm/io.h>
  16 #include <asm/mach-common/bits/twi.h>
  17
  18 /* Two-Wire Interface           (0xFFC01400 - 0xFFC014FF) */
  19 #ifdef TWI0_CLKDIV
  20 #define bfin_read_TWI_CLKDIV()               bfin_read_TWI0_CLKDIV()
  21 #define bfin_write_TWI_CLKDIV(val)           bfin_write_TWI0_CLKDIV(val)
  22 #define bfin_read_TWI_CONTROL()              bfin_read_TWI0_CONTROL()
  23 #define bfin_write_TWI_CONTROL(val)          bfin_write_TWI0_CONTROL(val)
  24 #define bfin_read_TWI_SLAVE_CTL()            bfin_read_TWI0_SLAVE_CTL()
  25 #define bfin_write_TWI_SLAVE_CTL(val)        bfin_write_TWI0_SLAVE_CTL(val)
  26 #define bfin_read_TWI_SLAVE_STAT()           bfin_read_TWI0_SLAVE_STAT()
  27 #define bfin_write_TWI_SLAVE_STAT(val)       bfin_write_TWI0_SLAVE_STAT(val)
  28 #define bfin_read_TWI_SLAVE_ADDR()           bfin_read_TWI0_SLAVE_ADDR()
  29 #define bfin_write_TWI_SLAVE_ADDR(val)       bfin_write_TWI0_SLAVE_ADDR(val)
  30 #define bfin_read_TWI_MASTER_CTL()           bfin_read_TWI0_MASTER_CTL()
  31 #define bfin_write_TWI_MASTER_CTL(val)       bfin_write_TWI0_MASTER_CTL(val)
  32 #define bfin_read_TWI_MASTER_STAT()          bfin_read_TWI0_MASTER_STAT()
  33 #define bfin_write_TWI_MASTER_STAT(val)      bfin_write_TWI0_MASTER_STAT(val)
  34 #define bfin_read_TWI_MASTER_ADDR()          bfin_read_TWI0_MASTER_ADDR()
  35 #define bfin_write_TWI_MASTER_ADDR(val)      bfin_write_TWI0_MASTER_ADDR(val)
  36 #define bfin_read_TWI_INT_STAT()             bfin_read_TWI0_INT_STAT()
  37 #define bfin_write_TWI_INT_STAT(val)         bfin_write_TWI0_INT_STAT(val)
  38 #define bfin_read_TWI_INT_MASK()             bfin_read_TWI0_INT_MASK()
  39 #define bfin_write_TWI_INT_MASK(val)         bfin_write_TWI0_INT_MASK(val)
  40 #define bfin_read_TWI_FIFO_CTL()             bfin_read_TWI0_FIFO_CTL()
  41 #define bfin_write_TWI_FIFO_CTL(val)         bfin_write_TWI0_FIFO_CTL(val)
  42 #define bfin_read_TWI_FIFO_STAT()            bfin_read_TWI0_FIFO_STAT()
  43 #define bfin_write_TWI_FIFO_STAT(val)        bfin_write_TWI0_FIFO_STAT(val)
  44 #define bfin_read_TWI_XMT_DATA8()            bfin_read_TWI0_XMT_DATA8()
  45 #define bfin_write_TWI_XMT_DATA8(val)        bfin_write_TWI0_XMT_DATA8(val)
  46 #define bfin_read_TWI_XMT_DATA_16()          bfin_read_TWI0_XMT_DATA16()
  47 #define bfin_write_TWI_XMT_DATA16(val)       bfin_write_TWI0_XMT_DATA16(val)
  48 #define bfin_read_TWI_RCV_DATA8()            bfin_read_TWI0_RCV_DATA8()
  49 #define bfin_write_TWI_RCV_DATA8(val)        bfin_write_TWI0_RCV_DATA8(val)
  50 #define bfin_read_TWI_RCV_DATA16()           bfin_read_TWI0_RCV_DATA16()
  51 #define bfin_write_TWI_RCV_DATA16(val)       bfin_write_TWI0_RCV_DATA16(val)
  52 #endif
  53
  54 #ifdef DEBUG_I2C
  55 #define PRINTD(fmt,args...)     do {    \
  56         DECLARE_GLOBAL_DATA_PTR;        \
  57         if (gd->have_console)           \
  58                 printf(fmt ,##args);    \
  59         } while (0)
  60 #else
  61 #define PRINTD(fmt,args...)
  62 #endif
  63
  64 #ifndef CONFIG_TWICLK_KHZ
  65 #define CONFIG_TWICLK_KHZ       50
  66 #endif
  67
  68 /* All transfers are described by this data structure */
  69 struct i2c_msg {
  70         u16 addr;               /* slave address */
  71         u16 flags;
  72 #define I2C_M_STOP              0x2
  73 #define I2C_M_RD                0x1
  74         u16 len;                /* msg length */
  75         u8 *buf;                /* pointer to msg data */
  76 };
  77
  78 /**
  79  * i2c_reset: - reset the host controller
  80  */
  81 static void i2c_reset(void)
  82 {
  83         /* Disable TWI */
  84         bfin_write_TWI_CONTROL(0);
  85         SSYNC();
  86
  87         /* Set TWI internal clock as 10MHz */
  88         bfin_write_TWI_CONTROL(((get_sclk() / 1024 / 1024 + 5) / 10) & 0x7F);
  89
  90         /* Set Twi interface clock as specified */
  91         if (CONFIG_TWICLK_KHZ > 400)
  92                 bfin_write_TWI_CLKDIV(((5 * 1024 / 400) << 8) | ((5 * 1024 /
  93                                                 400) & 0xFF));
  94         else
  95                 bfin_write_TWI_CLKDIV(((5 * 1024 /
  96                                         CONFIG_TWICLK_KHZ) << 8) | ((5 * 1024 /
  97                                                 CONFIG_TWICLK_KHZ)
  98                                                 & 0xFF));
  99
 100         /* Enable TWI */
 101         bfin_write_TWI_CONTROL(bfin_read_TWI_CONTROL() | TWI_ENA);
 102         SSYNC();
 103 }
 104
 105 int wait_for_completion(struct i2c_msg *msg, int timeout_count)
 106 {
 107         unsigned short twi_int_stat;
 108         unsigned short mast_stat;
 109         int i;
 110
 111         for (i = 0; i < timeout_count; i++) {
 112                 twi_int_stat = bfin_read_TWI_INT_STAT();
 113                 mast_stat = bfin_read_TWI_MASTER_STAT();
 114
 115                 if (XMTSERV & twi_int_stat) {
 116                         /* Transmit next data */
 117                         if (msg->len > 0) {
 118                                 bfin_write_TWI_XMT_DATA8(*(msg->buf++));
 119                                 msg->len--;
 120                         } else if (msg->flags & I2C_M_STOP)
 121                                 bfin_write_TWI_MASTER_CTL
 122                                     (bfin_read_TWI_MASTER_CTL() | STOP);
 123                         SSYNC();
 124                         /* Clear status */
 125                         bfin_write_TWI_INT_STAT(XMTSERV);
 126                         SSYNC();
 127                         i = 0;
 128                 }
 129                 if (RCVSERV & twi_int_stat) {
 130                         if (msg->len > 0) {
 131                                 /* Receive next data */
 132                                 *(msg->buf++) = bfin_read_TWI_RCV_DATA8();
 133                                 msg->len--;
 134                         } else if (msg->flags & I2C_M_STOP) {
 135                                 bfin_write_TWI_MASTER_CTL
 136                                     (bfin_read_TWI_MASTER_CTL() | STOP);
 137                                 SSYNC();
 138                         }
 139                         /* Clear interrupt source */
 140                         bfin_write_TWI_INT_STAT(RCVSERV);
 141                         SSYNC();
 142                         i = 0;
 143                 }
 144                 if (MERR & twi_int_stat) {
 145                         bfin_write_TWI_INT_STAT(MERR);
 146                         bfin_write_TWI_INT_MASK(0);
 147                         bfin_write_TWI_MASTER_STAT(0x3e);
 148                         bfin_write_TWI_MASTER_CTL(0);
 149                         SSYNC();
 150                         /*
 151                          * if both err and complete int stats are set,
 152                          * return proper results.
 153                          */
 154                         if (MCOMP & twi_int_stat) {
 155                                 bfin_write_TWI_INT_STAT(MCOMP);
 156                                 bfin_write_TWI_INT_MASK(0);
 157                                 bfin_write_TWI_MASTER_CTL(0);
 158                                 SSYNC();
 159                                 /*
 160                                  * If it is a quick transfer,
 161                                  * only address bug no data, not an err.
 162                                  */
 163                                 if (msg->len == 0 && mast_stat & BUFRDERR)
 164                                         return 0;
 165                                 /*
 166                                  * If address not acknowledged return -3,
 167                                  * else return 0.
 168                                  */
 169                                 else if (!(mast_stat & ANAK))
 170                                         return 0;
 171                                 else
 172                                         return -3;
 173                         }
 174                         return -1;
 175                 }
 176                 if (MCOMP & twi_int_stat) {
 177                         bfin_write_TWI_INT_STAT(MCOMP);
 178                         SSYNC();
 179                         bfin_write_TWI_INT_MASK(0);
 180                         bfin_write_TWI_MASTER_CTL(0);
 181                         SSYNC();
 182                         return 0;
 183                 }
 184         }
 185         if (msg->flags & I2C_M_RD)
 186                 return -4;
 187         else
 188                 return -2;
 189 }
 190
 191 /**
 192  * i2c_transfer: - Transfer one byte over the i2c bus
 193  *
 194  * This function can tranfer a byte over the i2c bus in both directions.
 195  * It is used by the public API functions.
 196  *
 197  * @return:      0: transfer successful
 198  *              -1: transfer fail
 199  *              -2: transmit timeout
 200  *              -3: ACK missing
 201  *              -4: receive timeout
 202  *              -5: controller not ready
 203  */
 204 int i2c_transfer(struct i2c_msg *msg)
 205 {
 206         int ret = 0;
 207         int timeout_count = 10000;
 208         int len = msg->len;
 209
 210         if (!(bfin_read_TWI_CONTROL() & TWI_ENA)) {
 211                 ret = -5;
 212                 goto transfer_error;
 213         }
 214
 215         while (bfin_read_TWI_MASTER_STAT() & BUSBUSY)
 216                 continue;
 217
 218         /* Set Transmit device address */
 219         bfin_write_TWI_MASTER_ADDR(msg->addr);
 220
 221         /*
 222          * FIFO Initiation.
 223          * Data in FIFO should be discarded before start a new operation.
 224          */
 225         bfin_write_TWI_FIFO_CTL(0x3);
 226         SSYNC();
 227         bfin_write_TWI_FIFO_CTL(0);
 228         SSYNC();
 229
 230         if (!(msg->flags & I2C_M_RD)) {
 231                 /* Transmit first data */
 232                 if (msg->len > 0) {
 233                         PRINTD("1 in i2c_transfer: buf=%d, len=%d\n", *msg->buf,
 234                                len);
 235                         bfin_write_TWI_XMT_DATA8(*(msg->buf++));
 236                         msg->len--;
 237                         SSYNC();
 238                 }
 239         }
 240
 241         /* clear int stat */
 242         bfin_write_TWI_INT_STAT(MERR | MCOMP | XMTSERV | RCVSERV);
 243
 244         /* Interrupt mask . Enable XMT, RCV interrupt */
 245         bfin_write_TWI_INT_MASK(MCOMP | MERR |
 246                         ((msg->flags & I2C_M_RD) ? RCVSERV : XMTSERV));
 247         SSYNC();
 248
 249         if (len > 0 && len <= 255)
 250                 bfin_write_TWI_MASTER_CTL((len << 6));
 251         else if (msg->len > 255) {
 252                 bfin_write_TWI_MASTER_CTL((0xff << 6));
 253                 msg->flags &= I2C_M_STOP;
 254         } else
 255                 bfin_write_TWI_MASTER_CTL(0);
 256
 257         /* Master enable */
 258         bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | MEN |
 259                         ((msg->flags & I2C_M_RD)
 260                          ? MDIR : 0) | ((CONFIG_TWICLK_KHZ >
 261                                          100) ? FAST : 0));
 262         SSYNC();
 263
 264         ret = wait_for_completion(msg, timeout_count);
 265         PRINTD("3 in i2c_transfer: ret=%d\n", ret);
 266
 267  transfer_error:
 268         switch (ret) {
 269         case 1:
 270                 PRINTD(("i2c_transfer: error: transfer fail\n"));
 271                 break;
 272         case 2:
 273                 PRINTD(("i2c_transfer: error: transmit timeout\n"));
 274                 break;
 275         case 3:
 276                 PRINTD(("i2c_transfer: error: ACK missing\n"));
 277                 break;
 278         case 4:
 279                 PRINTD(("i2c_transfer: error: receive timeout\n"));
 280                 break;
 281         case 5:
 282                 PRINTD(("i2c_transfer: error: controller not ready\n"));
 283                 i2c_reset();
 284                 break;
 285         default:
 286                 break;
 287         }
 288         return ret;
 289
 290 }
 291
 292 /* ---------------------------------------------------------------------*/
 293 /* API Functions                                                        */
 294 /* ---------------------------------------------------------------------*/
 295
 296 void i2c_init(int speed, int slaveaddr)
 297 {
 298         i2c_reset();
 299 }
 300
 301 /**
 302  * i2c_probe: - Test if a chip answers for a given i2c address
 303  *
 304  * @chip:       address of the chip which is searched for
 305  * @return:     0 if a chip was found, -1 otherwhise
 306  */
 307
 308 int i2c_probe(uchar chip)
 309 {
 310         struct i2c_msg msg;
 311         u8 probebuf;
 312
 313         i2c_reset();
 314
 315         probebuf = 0;
 316         msg.addr = chip;
 317         msg.flags = 0;
 318         msg.len = 1;
 319         msg.buf = &probebuf;
 320         if (i2c_transfer(&msg))
 321                 return -1;
 322
 323         msg.addr = chip;
 324         msg.flags = I2C_M_RD;
 325         msg.len = 1;
 326         msg.buf = &probebuf;
 327         if (i2c_transfer(&msg))
 328                 return -1;
 329
 330         return 0;
 331 }
 332
 333 /**
 334  *   i2c_read: - Read multiple bytes from an i2c device
 335  *
 336  *   chip:    I2C chip address, range 0..127
 337  *   addr:    Memory (register) address within the chip
 338  *   alen:    Number of bytes to use for addr (typically 1, 2 for larger
 339  *              memories, 0 for register type devices with only one
 340  *              register)
 341  *   buffer:  Where to read/write the data
 342  *   len:     How many bytes to read/write
 343  *
 344  *   Returns: 0 on success, not 0 on failure
 345  */
 346
 347 int i2c_read(uchar chip, uint addr, int alen, uchar * buffer, int len)
 348 {
 349         struct i2c_msg msg;
 350         u8 addr_bytes[3];       /* lowest...highest byte of data address */
 351
 352         PRINTD("i2c_read: chip=0x%x, addr=0x%x, alen=0x%x, len=0x%x\n", chip,
 353                         addr, alen, len);
 354
 355         if (alen > 0) {
 356                 addr_bytes[0] = (u8) ((addr >> 0) & 0x000000FF);
 357                 addr_bytes[1] = (u8) ((addr >> 8) & 0x000000FF);
 358                 addr_bytes[2] = (u8) ((addr >> 16) & 0x000000FF);
 359                 msg.addr = chip;
 360                 msg.flags = 0;
 361                 msg.len = alen;
 362                 msg.buf = addr_bytes;
 363                 if (i2c_transfer(&msg))
 364                         return -1;
 365         }
 366
 367         /* start read sequence */
 368         PRINTD(("i2c_read: start read sequence\n"));
 369         msg.addr = chip;
 370         msg.flags = I2C_M_RD;
 371         msg.len = len;
 372         msg.buf = buffer;
 373         if (i2c_transfer(&msg))
 374                 return -1;
 375
 376         return 0;
 377 }
 378
 379 /**
 380  *   i2c_write: -  Write multiple bytes to an i2c device
 381  *
 382  *   chip:    I2C chip address, range 0..127
 383  *   addr:    Memory (register) address within the chip
 384  *   alen:    Number of bytes to use for addr (typically 1, 2 for larger
 385  *              memories, 0 for register type devices with only one
 386  *              register)
 387  *   buffer:  Where to read/write the data
 388  *   len:     How many bytes to read/write
 389  *
 390  *   Returns: 0 on success, not 0 on failure
 391  */
 392
 393 int i2c_write(uchar chip, uint addr, int alen, uchar * buffer, int len)
 394 {
 395         struct i2c_msg msg;
 396         u8 addr_bytes[3];       /* lowest...highest byte of data address */
 397
 398         PRINTD
 399                 ("i2c_write: chip=0x%x, addr=0x%x, alen=0x%x, len=0x%x, buf0=0x%x\n",
 400                  chip, addr, alen, len, buffer[0]);
 401
 402         /* chip address write */
 403         if (alen > 0) {
 404                 addr_bytes[0] = (u8) ((addr >> 0) & 0x000000FF);
 405                 addr_bytes[1] = (u8) ((addr >> 8) & 0x000000FF);
 406                 addr_bytes[2] = (u8) ((addr >> 16) & 0x000000FF);
 407                 msg.addr = chip;
 408                 msg.flags = 0;
 409                 msg.len = alen;
 410                 msg.buf = addr_bytes;
 411                 if (i2c_transfer(&msg))
 412                         return -1;
 413         }
 414
 415         /* start read sequence */
 416         PRINTD(("i2c_write: start write sequence\n"));
 417         msg.addr = chip;
 418         msg.flags = 0;
 419         msg.len = len;
 420         msg.buf = buffer;
 421         if (i2c_transfer(&msg))
 422                 return -1;
 423
 424         return 0;
 425
 426 }
 427
 428 uchar i2c_reg_read(uchar chip, uchar reg)
 429 {
 430         uchar buf;
 431
 432         PRINTD("i2c_reg_read: chip=0x%02x, reg=0x%02x\n", chip, reg);
 433         i2c_read(chip, reg, 0, &buf, 1);
 434         return (buf);
 435 }
 436
 437 void i2c_reg_write(uchar chip, uchar reg, uchar val)
 438 {
 439         PRINTD("i2c_reg_write: chip=0x%02x, reg=0x%02x, val=0x%02x\n", chip,
 440                         reg, val);
 441         i2c_write(chip, reg, 0, &val, 1);
 442 }
 443
 444 #endif /* CONFIG_HARD_I2C */