cpu/xscale/i2c.c

   1 /*
   2  * (C) Copyright 2000
   3  * Paolo Scaffardi, AIRVENT SAM s.p.a - RIMINI(ITALY), arsenio@tin.it
   4  *
   5  * (C) Copyright 2000 Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   6  * Marius Groeger <mgroeger@sysgo.de>
   7  *
   8  * (C) Copyright 2003 Pengutronix e.K.
   9  * Robert Schwebel <r.schwebel@pengutronix.de>
  10  *
  11  * See file CREDITS for list of people who contributed to this
  12  * project.
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License as
  16  * published by the Free Software Foundation; either version 2 of
  17  * the License, or (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  27  * MA 02111-1307 USA
  28  *
  29  * Back ported to the 8xx platform (from the 8260 platform) by
  30  * Murray.Jensen@cmst.csiro.au, 27-Jan-01.
  31  */
  32
  33 /* FIXME: this file is PXA255 specific! What about other XScales? */
  34
  35 #include <common.h>
  36
  37 #ifdef CONFIG_HARD_I2C
  38
  39 /*
  40  *      - CFG_I2C_SPEED
  41  *      - I2C_PXA_SLAVE_ADDR
  42  */
  43
  44 #include <asm/arch/hardware.h>
  45 #include <asm/arch/pxa-regs.h>
  46 #include <i2c.h>
  47
  48 //#define       DEBUG_I2C       1       /* activate local debugging output  */
  49 #define I2C_PXA_SLAVE_ADDR      0x1     /* slave pxa unit address           */
  50 #define I2C_ICR_INIT            (ICR_BEIE | ICR_IRFIE | ICR_ITEIE | ICR_GCD | ICR_SCLE)
  51 #define I2C_ISR_INIT            0x7FF
  52
  53 #ifdef DEBUG_I2C
  54 #define PRINTD(x) printf x
  55 #else
  56 #define PRINTD(x)
  57 #endif
  58
  59
  60 /* Shall the current transfer have a start/stop condition? */
  61 #define I2C_COND_NORMAL         0
  62 #define I2C_COND_START          1
  63 #define I2C_COND_STOP           2
  64
  65 /* Shall the current transfer be ack/nacked or being waited for it? */
  66 #define I2C_ACKNAK_WAITACK      1
  67 #define I2C_ACKNAK_SENDACK      2
  68 #define I2C_ACKNAK_SENDNAK      4
  69
  70 /* Specify who shall transfer the data (master or slave) */
  71 #define I2C_READ                0
  72 #define I2C_WRITE               1
  73
  74 /* All transfers are described by this data structure */
  75 struct i2c_msg {
  76         u8 condition;
  77         u8 acknack;
  78         u8 direction;
  79         u8 data;
  80 };
  81
  82
  83 /**
  84  * i2c_pxa_reset: - reset the host controller
  85  *
  86  */
  87
  88 static void i2c_reset( void )
  89 {
  90         ICR &= ~ICR_IUE;                /* disable unit */
  91         ICR |= ICR_UR;                  /* reset the unit */
  92         udelay(100);
  93         ICR &= ~ICR_IUE;                /* disable unit */
  94         CKEN |= CKEN14_I2C;             /* set the global I2C clock on */
  95         ISAR = I2C_PXA_SLAVE_ADDR;      /* set our slave address */
  96         ICR = I2C_ICR_INIT;             /* set control register values */
  97         ISR = I2C_ISR_INIT;             /* set clear interrupt bits */
  98         ICR |= ICR_IUE;                 /* enable unit */
  99         udelay(100);
 100 }
 101
 102
 103 /**
 104  * i2c_isr_set_cleared: - wait until certain bits of the I2C status register
 105  *                        are set and cleared
 106  *
 107  * @return: 0 in case of success, 1 means timeout (no match within 10 ms).
 108  */
 109
 110 static int i2c_isr_set_cleared( unsigned long set_mask, unsigned long cleared_mask )
 111 {
 112         int timeout = 10000;
 113
 114         while( ((ISR & set_mask)!=set_mask) || ((ISR & cleared_mask)!=0) ){
 115                 udelay( 10 );
 116                 if( timeout-- < 0 ) return 0;
 117         }
 118
 119         return 1;
 120 }
 121
 122
 123 /**
 124  * i2c_transfer: - Transfer one byte over the i2c bus
 125  *
 126  * This function can tranfer a byte over the i2c bus in both directions.
 127  * It is used by the public API functions.
 128  *
 129  * @return:  0: transfer successful
 130  *          -1: message is empty
 131  *          -2: transmit timeout
 132  *          -3: ACK missing
 133  *          -4: receive timeout
 134  *          -5: illegal parameters
 135  *          -6: bus is busy and couldn't be aquired
 136  */
 137 int i2c_transfer(struct i2c_msg *msg)
 138 {
 139         int ret;
 140
 141         if (!msg)
 142                 goto transfer_error_msg_empty;
 143
 144         switch(msg->direction) {
 145
 146         case I2C_WRITE:
 147
 148                 /* check if bus is not busy */
 149                 if (!i2c_isr_set_cleared(0,ISR_IBB))
 150                         goto transfer_error_bus_busy;
 151
 152                 /* start transmission */
 153                 ICR &= ~ICR_START;
 154                 ICR &= ~ICR_STOP;
 155                 IDBR = msg->data;
 156                 if (msg->condition == I2C_COND_START)     ICR |=  ICR_START;
 157                 if (msg->condition == I2C_COND_STOP)      ICR |=  ICR_STOP;
 158                 if (msg->acknack   == I2C_ACKNAK_SENDNAK) ICR |=  ICR_ACKNAK;
 159                 if (msg->acknack   == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK;
 160                 ICR &= ~ICR_ALDIE;
 161                 ICR |= ICR_TB;
 162
 163                 /* transmit register empty? */
 164                 if (!i2c_isr_set_cleared(ISR_ITE,0))
 165                         goto transfer_error_transmit_timeout;
 166
 167                 /* clear 'transmit empty' state */
 168                 ISR |= ISR_ITE;
 169
 170                 /* wait for ACK from slave */
 171                 if (msg->acknack == I2C_ACKNAK_WAITACK)
 172                         if (!i2c_isr_set_cleared(0,ISR_ACKNAK))
 173                                 goto transfer_error_ack_missing;
 174                 break;
 175
 176         case I2C_READ:
 177
 178                 /* check if bus is not busy */
 179                 if (!i2c_isr_set_cleared(0,ISR_IBB))
 180                         goto transfer_error_bus_busy;
 181
 182                 /* start receive */
 183                 ICR &= ~ICR_START;
 184                 ICR &= ~ICR_STOP;
 185                 if (msg->condition == I2C_COND_START)     ICR |= ICR_START;
 186                 if (msg->condition == I2C_COND_STOP)      ICR |= ICR_STOP;
 187                 if (msg->acknack   == I2C_ACKNAK_SENDNAK) ICR |=  ICR_ACKNAK;
 188                 if (msg->acknack   == I2C_ACKNAK_SENDACK) ICR &= ~ICR_ACKNAK;
 189                 ICR &= ~ICR_ALDIE;
 190                 ICR |= ICR_TB;
 191
 192                 /* receive register full? */
 193                 if (!i2c_isr_set_cleared(ISR_IRF,0))
 194                         goto transfer_error_receive_timeout;
 195
 196                 msg->data = IDBR;
 197
 198                 /* clear 'receive empty' state */
 199                 ISR |= ISR_IRF;
 200
 201                 break;
 202
 203         default:
 204
 205                 goto transfer_error_illegal_param;
 206
 207         }
 208
 209         return 0;
 210
 211 transfer_error_msg_empty:
 212                 PRINTD(("i2c_transfer: error: 'msg' is empty\n"));
 213                 ret = -1; goto i2c_transfer_finish;
 214
 215 transfer_error_transmit_timeout:
 216                 PRINTD(("i2c_transfer: error: transmit timeout\n"));
 217                 ret = -2; goto i2c_transfer_finish;
 218
 219 transfer_error_ack_missing:
 220                 PRINTD(("i2c_transfer: error: ACK missing\n"));
 221                 ret = -3; goto i2c_transfer_finish;
 222
 223 transfer_error_receive_timeout:
 224                 PRINTD(("i2c_transfer: error: receive timeout\n"));
 225                 ret = -4; goto i2c_transfer_finish;
 226
 227 transfer_error_illegal_param:
 228                 PRINTD(("i2c_transfer: error: illegal parameters\n"));
 229                 ret = -5; goto i2c_transfer_finish;
 230
 231 transfer_error_bus_busy:
 232                 PRINTD(("i2c_transfer: error: bus is busy\n"));
 233                 ret = -6; goto i2c_transfer_finish;
 234
 235 i2c_transfer_finish:
 236                 PRINTD(("i2c_transfer: ISR: 0x%04x\n",ISR));
 237                 i2c_reset();
 238                 return ret;
 239
 240 }
 241
 242 /* ------------------------------------------------------------------------ */
 243 /* API Functions                                                            */
 244 /* ------------------------------------------------------------------------ */
 245
 246 void i2c_init(int speed, int slaveaddr)
 247 {
 248 #ifdef CFG_I2C_INIT_BOARD
 249         /* call board specific i2c bus reset routine before accessing the   */
 250         /* environment, which might be in a chip on that bus. For details   */
 251         /* about this problem see doc/I2C_Edge_Conditions.                  */
 252         i2c_init_board();
 253 #endif
 254 }
 255
 256
 257 /**
 258  * i2c_probe: - Test if a chip answers for a given i2c address
 259  *
 260  * @chip:       address of the chip which is searched for
 261  * @return:     0 if a chip was found, -1 otherwhise
 262  */
 263
 264 int i2c_probe(uchar chip)
 265 {
 266         struct i2c_msg msg;
 267
 268         i2c_reset();
 269
 270         msg.condition = I2C_COND_START;
 271         msg.acknack   = I2C_ACKNAK_WAITACK;
 272         msg.direction = I2C_WRITE;
 273         msg.data      = (chip << 1) + 1;
 274         if (i2c_transfer(&msg)) return -1;
 275
 276         msg.condition = I2C_COND_STOP;
 277         msg.acknack   = I2C_ACKNAK_SENDNAK;
 278         msg.direction = I2C_READ;
 279         msg.data      = 0x00;
 280         if (i2c_transfer(&msg)) return -1;
 281
 282         return 0;
 283 }
 284
 285
 286 /**
 287  * i2c_read: - Read multiple bytes from an i2c device
 288  *
 289  * The higher level routines take into account that this function is only
 290  * called with len < page length of the device (see configuration file)
 291  *
 292  * @chip:       address of the chip which is to be read
 293  * @addr:       i2c data address within the chip
 294  * @alen:       length of the i2c data address (1..2 bytes)
 295  * @buffer:     where to write the data
 296  * @len:        how much byte do we want to read
 297  * @return:     0 in case of success
 298  */
 299
 300 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 301 {
 302         struct i2c_msg msg;
 303         u8 addr_bytes[3]; /* lowest...highest byte of data address */
 304         int ret;
 305
 306         PRINTD(("i2c_read(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
 307
 308         i2c_reset();
 309
 310         /* dummy chip address write */
 311         PRINTD(("i2c_read: dummy chip address write\n"));
 312         msg.condition = I2C_COND_START;
 313         msg.acknack   = I2C_ACKNAK_WAITACK;
 314         msg.direction = I2C_WRITE;
 315         msg.data      = (chip << 1);
 316         msg.data     &= 0xFE;
 317         if ((ret=i2c_transfer(&msg))) return -1;
 318
 319         /*
 320          * send memory address bytes;
 321          * alen defines how much bytes we have to send.
 322          */
 323         //addr &= ((1 << CFG_EEPROM_PAGE_WRITE_BITS)-1);
 324         addr_bytes[0] = (u8)((addr >>  0) & 0x000000FF);
 325         addr_bytes[1] = (u8)((addr >>  8) & 0x000000FF);
 326         addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
 327
 328         while (--alen >= 0) {
 329
 330                 PRINTD(("i2c_read: send memory word address byte %1d\n",alen));
 331                 msg.condition = I2C_COND_NORMAL;
 332                 msg.acknack   = I2C_ACKNAK_WAITACK;
 333                 msg.direction = I2C_WRITE;
 334                 msg.data      = addr_bytes[alen];
 335                 if ((ret=i2c_transfer(&msg))) return -1;
 336         }
 337
 338
 339         /* start read sequence */
 340         PRINTD(("i2c_read: start read sequence\n"));
 341         msg.condition = I2C_COND_START;
 342         msg.acknack   = I2C_ACKNAK_WAITACK;
 343         msg.direction = I2C_WRITE;
 344         msg.data      = (chip << 1);
 345         msg.data     |= 0x01;
 346         if ((ret=i2c_transfer(&msg))) return -1;
 347
 348         /* read bytes; send NACK at last byte */
 349         while (len--) {
 350
 351                 if (len==0) {
 352                         msg.condition = I2C_COND_STOP;
 353                         msg.acknack   = I2C_ACKNAK_SENDNAK;
 354                 } else {
 355                         msg.condition = I2C_COND_NORMAL;
 356                         msg.acknack   = I2C_ACKNAK_SENDACK;
 357                 }
 358
 359                 msg.direction = I2C_READ;
 360                 msg.data      = 0x00;
 361                 if ((ret=i2c_transfer(&msg))) return -1;
 362
 363                 *(buffer++) = msg.data;
 364
 365                 PRINTD(("i2c_read: reading byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
 366
 367         }
 368
 369         i2c_reset();
 370
 371         return 0;
 372 }
 373
 374
 375 /**
 376  * i2c_write: -  Write multiple bytes to an i2c device
 377  *
 378  * The higher level routines take into account that this function is only
 379  * called with len < page length of the device (see configuration file)
 380  *
 381  * @chip:       address of the chip which is to be written
 382  * @addr:       i2c data address within the chip
 383  * @alen:       length of the i2c data address (1..2 bytes)
 384  * @buffer:     where to find the data to be written
 385  * @len:        how much byte do we want to read
 386  * @return:     0 in case of success
 387  */
 388
 389 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 390 {
 391         struct i2c_msg msg;
 392         u8 addr_bytes[3]; /* lowest...highest byte of data address */
 393
 394         PRINTD(("i2c_write(chip=0x%02x, addr=0x%02x, alen=0x%02x, len=0x%02x)\n",chip,addr,alen,len));
 395
 396         i2c_reset();
 397
 398         /* chip address write */
 399         PRINTD(("i2c_write: chip address write\n"));
 400         msg.condition = I2C_COND_START;
 401         msg.acknack   = I2C_ACKNAK_WAITACK;
 402         msg.direction = I2C_WRITE;
 403         msg.data      = (chip << 1);
 404         msg.data     &= 0xFE;
 405         if (i2c_transfer(&msg)) return -1;
 406
 407         /*
 408          * send memory address bytes;
 409          * alen defines how much bytes we have to send.
 410          */
 411         addr_bytes[0] = (u8)((addr >>  0) & 0x000000FF);
 412         addr_bytes[1] = (u8)((addr >>  8) & 0x000000FF);
 413         addr_bytes[2] = (u8)((addr >> 16) & 0x000000FF);
 414
 415         while (--alen >= 0) {
 416
 417                 PRINTD(("i2c_write: send memory word address\n"));
 418                 msg.condition = I2C_COND_NORMAL;
 419                 msg.acknack   = I2C_ACKNAK_WAITACK;
 420                 msg.direction = I2C_WRITE;
 421                 msg.data      = addr_bytes[alen];
 422                 if (i2c_transfer(&msg)) return -1;
 423         }
 424
 425         /* write bytes; send NACK at last byte */
 426         while (len--) {
 427
 428                 PRINTD(("i2c_write: writing byte (0x%08x)=0x%02x\n",(unsigned int)buffer,*buffer));
 429
 430                 if (len==0)
 431                         msg.condition = I2C_COND_STOP;
 432                 else
 433                         msg.condition = I2C_COND_NORMAL;
 434
 435                 msg.acknack   = I2C_ACKNAK_WAITACK;
 436                 msg.direction = I2C_WRITE;
 437                 msg.data      = *(buffer++);
 438
 439                 if (i2c_transfer(&msg)) return -1;
 440
 441         }
 442
 443         i2c_reset();
 444
 445         return 0;
 446
 447 }
 448
 449 uchar i2c_reg_read (uchar chip, uchar reg)
 450 {
 451         PRINTD(("i2c_reg_read(chip=0x%02x, reg=0x%02x)\n",chip,reg));
 452         return 0;
 453 }
 454
 455 void  i2c_reg_write(uchar chip, uchar reg, uchar val)
 456 {
 457         PRINTD(("i2c_reg_write(chip=0x%02x, reg=0x%02x, val=0x%02x)\n",chip,reg,val));
 458 }
 459
 460 #endif  /* CONFIG_HARD_I2C */