cpu/mpc512x/i2c.c

   1 /*
   2  * (C) Copyright 2003 - 2007
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * See file CREDITS for list of people who contributed to this
   6  * project.
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License as
  10  * published by the Free Software Foundation; either version 2 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21  * MA 02111-1307 USA
  22  *
  23  * Based on the MPC5xxx code.
  24  */
  25
  26 #include <common.h>
  27
  28 DECLARE_GLOBAL_DATA_PTR;
  29
  30 #ifdef CONFIG_HARD_I2C
  31
  32 #include <mpc512x.h>
  33 #include <i2c.h>
  34
  35 #define immr ((immap_t *)CFG_IMMR)
  36
  37 /* by default set I2C bus 0 active */
  38 static unsigned int bus_num = 0;
  39
  40 #define I2C_TIMEOUT     100
  41 #define I2C_RETRIES     3
  42
  43 struct mpc512x_i2c_tap {
  44         int scl2tap;
  45         int tap2tap;
  46 };
  47
  48 static int  mpc_reg_in(volatile u32 *reg);
  49 static void mpc_reg_out(volatile u32 *reg, int val, int mask);
  50 static int  wait_for_bb(void);
  51 static int  wait_for_pin(int *status);
  52 static int  do_address(uchar chip, char rdwr_flag);
  53 static int  send_bytes(uchar chip, char *buf, int len);
  54 static int  receive_bytes(uchar chip, char *buf, int len);
  55 static int  mpc_get_fdr(int);
  56
  57 static int mpc_reg_in (volatile u32 *reg)
  58 {
  59         int ret = *reg >> 24;
  60         __asm__ __volatile__ ("eieio");
  61         return ret;
  62 }
  63
  64 static void mpc_reg_out (volatile u32 *reg, int val, int mask)
  65 {
  66         int tmp;
  67
  68         if (!mask) {
  69                 *reg = val << 24;
  70         } else {
  71                 tmp = mpc_reg_in (reg);
  72                 *reg = ((tmp & ~mask) | (val & mask)) << 24;
  73         }
  74         __asm__ __volatile__ ("eieio");
  75
  76         return;
  77 }
  78
  79 static int wait_for_bb (void)
  80 {
  81         i2c512x_dev_t *regs = &immr->i2c.dev[bus_num];
  82         int timeout = I2C_TIMEOUT;
  83         int status;
  84
  85         status = mpc_reg_in (&regs->msr);
  86
  87         while (timeout-- && (status & I2C_BB)) {
  88                 volatile int temp;
  89                 mpc_reg_out (&regs->mcr, I2C_STA, I2C_STA);
  90                 temp = mpc_reg_in (&regs->mdr);
  91                 mpc_reg_out (&regs->mcr, 0, I2C_STA);
  92                 mpc_reg_out (&regs->mcr, 0, 0);
  93                 mpc_reg_out (&regs->mcr, I2C_EN, 0);
  94
  95                 udelay (1000);
  96                 status = mpc_reg_in (&regs->msr);
  97         }
  98
  99         return (status & I2C_BB);
 100 }
 101
 102 static int wait_for_pin (int *status)
 103 {
 104         i2c512x_dev_t *regs = &immr->i2c.dev[bus_num];
 105         int timeout = I2C_TIMEOUT;
 106
 107         *status = mpc_reg_in (&regs->msr);
 108
 109         while (timeout-- && !(*status & I2C_IF)) {
 110                 udelay (1000);
 111                 *status = mpc_reg_in (&regs->msr);
 112         }
 113
 114         if (!(*status & I2C_IF)) {
 115                 return -1;
 116         }
 117
 118         mpc_reg_out (&regs->msr, 0, I2C_IF);
 119
 120         return 0;
 121 }
 122
 123 static int do_address (uchar chip, char rdwr_flag)
 124 {
 125         i2c512x_dev_t *regs = &immr->i2c.dev[bus_num];
 126         int status;
 127
 128         chip <<= 1;
 129
 130         if (rdwr_flag) {
 131                 chip |= 1;
 132         }
 133
 134         mpc_reg_out (&regs->mcr, I2C_TX, I2C_TX);
 135         mpc_reg_out (&regs->mdr, chip, 0);
 136
 137         if (wait_for_pin (&status)) {
 138                 return -2;
 139         }
 140
 141         if (status & I2C_RXAK) {
 142                 return -3;
 143         }
 144
 145         return 0;
 146 }
 147
 148 static int send_bytes (uchar chip, char *buf, int len)
 149 {
 150         i2c512x_dev_t *regs = &immr->i2c.dev[bus_num];
 151         int wrcount;
 152         int status;
 153
 154         for (wrcount = 0; wrcount < len; ++wrcount) {
 155
 156                 mpc_reg_out (&regs->mdr, buf[wrcount], 0);
 157
 158                 if (wait_for_pin (&status)) {
 159                         break;
 160                 }
 161
 162                 if (status & I2C_RXAK) {
 163                         break;
 164                 }
 165
 166         }
 167
 168         return !(wrcount == len);
 169 }
 170
 171 static int receive_bytes (uchar chip, char *buf, int len)
 172 {
 173         i2c512x_dev_t *regs = &immr->i2c.dev[bus_num];
 174         int dummy   = 1;
 175         int rdcount = 0;
 176         int status;
 177         int i;
 178
 179         mpc_reg_out (&regs->mcr, 0, I2C_TX);
 180
 181         for (i = 0; i < len; ++i) {
 182                 buf[rdcount] = mpc_reg_in (&regs->mdr);
 183
 184                 if (dummy) {
 185                         dummy = 0;
 186                 } else {
 187                         rdcount++;
 188                 }
 189
 190                 if (wait_for_pin (&status)) {
 191                         return -4;
 192                 }
 193         }
 194
 195         mpc_reg_out (&regs->mcr, I2C_TXAK, I2C_TXAK);
 196         buf[rdcount++] = mpc_reg_in (&regs->mdr);
 197
 198         if (wait_for_pin (&status)) {
 199                 return -5;
 200         }
 201
 202         mpc_reg_out (&regs->mcr, 0, I2C_TXAK);
 203
 204         return 0;
 205 }
 206
 207 /**************** I2C API ****************/
 208
 209 void i2c_init (int speed, int saddr)
 210 {
 211         int i;
 212         for(i = 0; i < I2C_BUS_CNT; i++){
 213                 i2c512x_dev_t *regs = &immr->i2c.dev[i];
 214                 mpc_reg_out (&regs->mcr, 0, 0);
 215
 216                 /* Set clock */
 217                 mpc_reg_out (&regs->mfdr, mpc_get_fdr (speed), 0);
 218                 mpc_reg_out (&regs->madr, saddr << 1, 0);
 219
 220                 /* Enable module */
 221                 mpc_reg_out (&regs->mcr, I2C_EN, I2C_INIT_MASK);
 222                 mpc_reg_out (&regs->msr, 0, I2C_IF);
 223         }
 224
 225         /* Disable interrupts */
 226         immr->i2c.icr = 0;
 227         /* Turn off filters */
 228         immr->i2c.mifr = 0;
 229         return;
 230 }
 231
 232 static int mpc_get_fdr (int speed)
 233 {
 234         static int fdr = -1;
 235
 236         if (fdr == -1) {
 237                 ulong best_speed = 0;
 238                 ulong divider;
 239                 ulong ips, scl;
 240                 ulong bestmatch = 0xffffffffUL;
 241                 int best_i = 0, best_j = 0, i, j;
 242                 int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8};
 243                 struct mpc512x_i2c_tap scltap[] = {
 244                         {4, 1},
 245                         {4, 2},
 246                         {6, 4},
 247                         {6, 8},
 248                         {14, 16},
 249                         {30, 32},
 250                         {62, 64},
 251                         {126, 128}
 252                 };
 253
 254                 ips = gd->ips_clk;
 255                 for (i = 7; i >= 0; i--) {
 256                         for (j = 7; j >= 0; j--) {
 257                                 scl = 2 * (scltap[j].scl2tap +
 258                                            (SCL_Tap[i] - 1) * scltap[j].tap2tap
 259                                            + 2);
 260                                 if (ips <= speed*scl) {
 261                                         if ((speed*scl - ips) < bestmatch) {
 262                                                 bestmatch = speed*scl - ips;
 263                                                 best_i = i;
 264                                                 best_j = j;
 265                                                 best_speed = ips/scl;
 266                                         }
 267                                 }
 268                         }
 269                 }
 270                 divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2);
 271                 if (gd->flags & GD_FLG_RELOC) {
 272                         fdr = divider;
 273                 } else {
 274                         debug("%ld kHz, \n", best_speed / 1000);
 275                         return divider;
 276                 }
 277         }
 278
 279         return fdr;
 280 }
 281
 282 int i2c_probe (uchar chip)
 283 {
 284         i2c512x_dev_t *regs = &immr->i2c.dev[bus_num];
 285         int i;
 286
 287         for (i = 0; i < I2C_RETRIES; i++) {
 288                 mpc_reg_out (&regs->mcr, I2C_STA, I2C_STA);
 289
 290                 if (! do_address (chip, 0)) {
 291                         mpc_reg_out (&regs->mcr, 0, I2C_STA);
 292                         udelay (500);
 293                         break;
 294                 }
 295
 296                 mpc_reg_out (&regs->mcr, 0, I2C_STA);
 297                 udelay (500);
 298         }
 299
 300         return (i == I2C_RETRIES);
 301 }
 302
 303 int i2c_read (uchar chip, uint addr, int alen, uchar *buf, int len)
 304 {
 305         char xaddr[4];
 306         i2c512x_dev_t *regs = &immr->i2c.dev[bus_num];
 307         int ret = -1;
 308
 309         xaddr[0] = (addr >> 24) & 0xFF;
 310         xaddr[1] = (addr >> 16) & 0xFF;
 311         xaddr[2] = (addr >>  8) & 0xFF;
 312         xaddr[3] =  addr        & 0xFF;
 313
 314         if (wait_for_bb ()) {
 315                 printf ("i2c_read: bus is busy\n");
 316                 goto Done;
 317         }
 318
 319         mpc_reg_out (&regs->mcr, I2C_STA, I2C_STA);
 320         if (do_address (chip, 0)) {
 321                 printf ("i2c_read: failed to address chip\n");
 322                 goto Done;
 323         }
 324
 325         if (send_bytes (chip, &xaddr[4-alen], alen)) {
 326                 printf ("i2c_read: send_bytes failed\n");
 327                 goto Done;
 328         }
 329
 330         mpc_reg_out (&regs->mcr, I2C_RSTA, I2C_RSTA);
 331         if (do_address (chip, 1)) {
 332                 printf ("i2c_read: failed to address chip\n");
 333                 goto Done;
 334         }
 335
 336         if (receive_bytes (chip, (char *)buf, len)) {
 337                 printf ("i2c_read: receive_bytes failed\n");
 338                 goto Done;
 339         }
 340
 341         ret = 0;
 342 Done:
 343         mpc_reg_out (&regs->mcr, 0, I2C_STA);
 344         return ret;
 345 }
 346
 347 int i2c_write (uchar chip, uint addr, int alen, uchar *buf, int len)
 348 {
 349         char xaddr[4];
 350         i2c512x_dev_t *regs = &immr->i2c.dev[bus_num];
 351         int ret = -1;
 352
 353         xaddr[0] = (addr >> 24) & 0xFF;
 354         xaddr[1] = (addr >> 16) & 0xFF;
 355         xaddr[2] = (addr >>  8) & 0xFF;
 356         xaddr[3] =  addr        & 0xFF;
 357
 358         if (wait_for_bb ()) {
 359                 printf ("i2c_write: bus is busy\n");
 360                 goto Done;
 361         }
 362
 363         mpc_reg_out (&regs->mcr, I2C_STA, I2C_STA);
 364         if (do_address (chip, 0)) {
 365                 printf ("i2c_write: failed to address chip\n");
 366                 goto Done;
 367         }
 368
 369         if (send_bytes (chip, &xaddr[4-alen], alen)) {
 370                 printf ("i2c_write: send_bytes failed\n");
 371                 goto Done;
 372         }
 373
 374         if (send_bytes (chip, (char *)buf, len)) {
 375                 printf ("i2c_write: send_bytes failed\n");
 376                 goto Done;
 377         }
 378
 379         ret = 0;
 380 Done:
 381         mpc_reg_out (&regs->mcr, 0, I2C_STA);
 382         return ret;
 383 }
 384
 385 uchar i2c_reg_read (uchar chip, uchar reg)
 386 {
 387         uchar buf;
 388
 389         i2c_read (chip, reg, 1, &buf, 1);
 390
 391         return buf;
 392 }
 393
 394 void i2c_reg_write (uchar chip, uchar reg, uchar val)
 395 {
 396         i2c_write (chip, reg, 1, &val, 1);
 397
 398         return;
 399 }
 400
 401
 402 int i2c_set_bus_num (unsigned int bus)
 403 {
 404         if (bus >= I2C_BUS_CNT) {
 405                 return -1;
 406         }
 407         bus_num = bus;
 408
 409         return 0;
 410 }
 411
 412 unsigned int i2c_get_bus_num (void)
 413 {
 414         return bus_num;
 415 }
 416
 417 /* TODO */
 418 unsigned int i2c_get_bus_speed (void)
 419 {
 420         return -1;
 421 }
 422
 423 int i2c_set_bus_speed (unsigned int speed)
 424 {
 425         if (speed != CFG_I2C_SPEED)
 426                 return -1;
 427
 428         return 0;
 429 }
 430
 431 #endif  /* CONFIG_HARD_I2C */