cpu/mpc5xxx/i2c.c

   1 /*
   2  * (C) Copyright 2003
   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
  24 #include <common.h>
  25
  26 #ifdef CONFIG_HARD_I2C
  27
  28 #include <mpc5xxx.h>
  29 #include <i2c.h>
  30
  31 #if (CFG_I2C_MODULE == 2)
  32 #define I2C_BASE        MPC5XXX_I2C2
  33 #elif (CFG_I2C_MODULE == 1)
  34 #define I2C_BASE        MPC5XXX_I2C1
  35 #else
  36 #error CFG_I2C_MODULE is not properly configured
  37 #endif
  38
  39 #define I2C_TIMEOUT     100
  40 #define I2C_RETRIES     3
  41
  42 struct mpc5xxx_i2c_tap {
  43         int scl2tap;
  44         int tap2tap;
  45 };
  46
  47 static int  mpc_reg_in    (volatile u32 *reg);
  48 static void mpc_reg_out   (volatile u32 *reg, int val, int mask);
  49 static int  wait_for_bb   (void);
  50 static int  wait_for_pin  (int *status);
  51 static int  do_address    (uchar chip, char rdwr_flag);
  52 static int  send_bytes    (uchar chip, char *buf, int len);
  53 static int  receive_bytes (uchar chip, char *buf, int len);
  54 static int  mpc_get_fdr   (int);
  55
  56 static int mpc_reg_in(volatile u32 *reg)
  57 {
  58         return *reg >> 24;
  59         __asm__ __volatile__ ("eieio");
  60 }
  61
  62 static void mpc_reg_out(volatile u32 *reg, int val, int mask)
  63 {
  64         int tmp;
  65
  66         if (!mask) {
  67                 *reg = val << 24;
  68         } else {
  69                 tmp = mpc_reg_in(reg);
  70                 *reg = ((tmp & ~mask) | (val & mask)) << 24;
  71         }
  72         __asm__ __volatile__ ("eieio");
  73
  74         return;
  75 }
  76
  77 static int wait_for_bb(void)
  78 {
  79         struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
  80         int                 timeout = I2C_TIMEOUT;
  81         int                 status;
  82
  83         status = mpc_reg_in(&regs->msr);
  84
  85         while (timeout-- && (status & I2C_BB)) {
  86 #if 1
  87                 volatile int temp;
  88                 mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
  89                 temp = mpc_reg_in(&regs->mdr);
  90                 mpc_reg_out(&regs->mcr, 0, I2C_STA);
  91                 mpc_reg_out(&regs->mcr, 0, 0);
  92                 mpc_reg_out(&regs->mcr, I2C_EN, 0);
  93 #endif
  94                 udelay(1000);
  95                 status = mpc_reg_in(&regs->msr);
  96         }
  97
  98         return (status & I2C_BB);
  99 }
 100
 101 static int wait_for_pin(int *status)
 102 {
 103         struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
 104         int                 timeout = I2C_TIMEOUT;
 105
 106         *status = mpc_reg_in(&regs->msr);
 107
 108         while (timeout-- && !(*status & I2C_IF)) {
 109                 udelay(1000);
 110                 *status = mpc_reg_in(&regs->msr);
 111         }
 112
 113         if (!(*status & I2C_IF)) {
 114                 return -1;
 115         }
 116
 117         mpc_reg_out(&regs->msr, 0, I2C_IF);
 118
 119         return 0;
 120 }
 121
 122 static int do_address(uchar chip, char rdwr_flag)
 123 {
 124         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 125         int                 status;
 126
 127         chip <<= 1;
 128
 129         if (rdwr_flag) {
 130                 chip |= 1;
 131         }
 132
 133         mpc_reg_out(&regs->mcr, I2C_TX, I2C_TX);
 134         mpc_reg_out(&regs->mdr, chip, 0);
 135
 136         if (wait_for_pin(&status)) {
 137                 return -2;
 138         }
 139
 140         if (status & I2C_RXAK) {
 141                 return -3;
 142         }
 143
 144         return 0;
 145 }
 146
 147 static int send_bytes(uchar chip, char *buf, int len)
 148 {
 149         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 150         int                 wrcount;
 151         int                 status;
 152
 153         for (wrcount = 0; wrcount < len; ++wrcount) {
 154
 155                 mpc_reg_out(&regs->mdr, buf[wrcount], 0);
 156
 157                 if (wait_for_pin(&status)) {
 158                         break;
 159                 }
 160
 161                 if (status & I2C_RXAK) {
 162                         break;
 163                 }
 164
 165         }
 166
 167         return !(wrcount == len);
 168 }
 169
 170 static int receive_bytes(uchar chip, char *buf, int len)
 171 {
 172         struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
 173         int                 dummy   = 1;
 174         int                 rdcount = 0;
 175         int                 status;
 176         int                 i;
 177
 178         mpc_reg_out(&regs->mcr, 0, I2C_TX);
 179
 180         for (i = 0; i < len; ++i) {
 181                 buf[rdcount] = mpc_reg_in(&regs->mdr);
 182
 183                 if (dummy) {
 184                         dummy = 0;
 185                 } else {
 186                         rdcount++;
 187                 }
 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         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 212
 213         mpc_reg_out(&regs->mcr, 0, 0);
 214         mpc_reg_out(&regs->madr, saddr << 1, 0);
 215
 216         /* Set clock
 217          */
 218         mpc_reg_out(&regs->mfdr, mpc_get_fdr(speed), 0);
 219
 220         /* Enable module
 221          */
 222         mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
 223         mpc_reg_out(&regs->msr, 0, I2C_IF);
 224
 225         return;
 226 }
 227
 228 static int mpc_get_fdr(int speed)
 229 {
 230         DECLARE_GLOBAL_DATA_PTR;
 231         static int fdr = -1;
 232
 233         if (fdr == -1) {
 234                 ulong best_speed = 0;
 235                 ulong divider;
 236                 ulong ipb, scl;
 237                 ulong bestmatch = 0xffffffffUL;
 238                 int best_i = 0, best_j = 0, i, j;
 239                 int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8};
 240                 struct mpc5xxx_i2c_tap scltap[] = {
 241                         {4, 1},
 242                         {4, 2},
 243                         {6, 4},
 244                         {6, 8},
 245                         {14, 16},
 246                         {30, 32},
 247                         {62, 64},
 248                         {126, 128}
 249                 };
 250
 251                 ipb = gd->ipb_clk;
 252                 for (i = 7; i >= 0; i--) {
 253                         for (j = 7; j >= 0; j--) {
 254                                 scl = 2 * (scltap[j].scl2tap +
 255                                         (SCL_Tap[i] - 1) * scltap[j].tap2tap + 2);
 256                                 if (ipb <= speed*scl) {
 257                                         if ((speed*scl - ipb) < bestmatch) {
 258                                                 bestmatch = speed*scl - ipb;
 259                                                 best_i = i;
 260                                                 best_j = j;
 261                                                 best_speed = ipb/scl;
 262                                         }
 263                                 }
 264                         }
 265                 }
 266                 divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2);
 267                 if (gd->flags & GD_FLG_RELOC) {
 268                         fdr = divider;
 269                 } else {
 270                         printf("%ld kHz, ", best_speed / 1000);
 271                         return divider;
 272                 }
 273         }
 274
 275         return fdr;
 276 }
 277
 278 int i2c_probe(uchar chip)
 279 {
 280         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 281         int                 i;
 282
 283         for (i = 0; i < I2C_RETRIES; i++) {
 284                 mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 285
 286                 if (! do_address(chip, 0)) {
 287                         mpc_reg_out(&regs->mcr, 0, I2C_STA);
 288                         break;
 289                 }
 290
 291                 mpc_reg_out(&regs->mcr, 0, I2C_STA);
 292                 udelay(500);
 293         }
 294
 295         return (i == I2C_RETRIES);
 296 }
 297
 298 int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
 299 {
 300         uchar                xaddr[4];
 301         struct mpc5xxx_i2c * regs        = (struct mpc5xxx_i2c *)I2C_BASE;
 302         int                  ret         = -1;
 303
 304         xaddr[0] = (addr >> 24) & 0xFF;
 305         xaddr[1] = (addr >> 16) & 0xFF;
 306         xaddr[2] = (addr >>  8) & 0xFF;
 307         xaddr[3] =  addr        & 0xFF;
 308
 309         if (wait_for_bb()) {
 310                 printf("i2c_read: bus is busy\n");
 311                 goto Done;
 312         }
 313
 314         mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 315         if (do_address(chip, 0)) {
 316                 printf("i2c_read: failed to address chip\n");
 317                 goto Done;
 318         }
 319
 320         if (send_bytes(chip, &xaddr[4-alen], alen)) {
 321                 printf("i2c_read: send_bytes failed\n");
 322                 goto Done;
 323         }
 324
 325         mpc_reg_out(&regs->mcr, I2C_RSTA, I2C_RSTA);
 326         if (do_address(chip, 1)) {
 327                 printf("i2c_read: failed to address chip\n");
 328                 goto Done;
 329         }
 330
 331         if (receive_bytes(chip, buf, len)) {
 332                 printf("i2c_read: receive_bytes failed\n");
 333                 goto Done;
 334         }
 335
 336         ret = 0;
 337 Done:
 338         mpc_reg_out(&regs->mcr, 0, I2C_STA);
 339         return ret;
 340 }
 341
 342 int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
 343 {
 344         uchar               xaddr[4];
 345         struct mpc5xxx_i2c *regs        = (struct mpc5xxx_i2c *)I2C_BASE;
 346         int                 ret         = -1;
 347
 348         xaddr[0] = (addr >> 24) & 0xFF;
 349         xaddr[1] = (addr >> 16) & 0xFF;
 350         xaddr[2] = (addr >>  8) & 0xFF;
 351         xaddr[3] =  addr        & 0xFF;
 352
 353         if (wait_for_bb()) {
 354                 printf("i2c_write: bus is busy\n");
 355                 goto Done;
 356         }
 357
 358         mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 359         if (do_address(chip, 0)) {
 360                 printf("i2c_write: failed to address chip\n");
 361                 goto Done;
 362         }
 363
 364         if (send_bytes(chip, &xaddr[4-alen], alen)) {
 365                 printf("i2c_write: send_bytes failed\n");
 366                 goto Done;
 367         }
 368
 369         if (send_bytes(chip, buf, len)) {
 370                 printf("i2c_write: send_bytes failed\n");
 371                 goto Done;
 372         }
 373
 374         ret = 0;
 375 Done:
 376         mpc_reg_out(&regs->mcr, 0, I2C_STA);
 377         return ret;
 378 }
 379
 380 uchar i2c_reg_read(uchar chip, uchar reg)
 381 {
 382         char buf;
 383
 384         i2c_read(chip, reg, 1, &buf, 1);
 385
 386         return buf;
 387 }
 388
 389 void i2c_reg_write(uchar chip, uchar reg, uchar val)
 390 {
 391         i2c_write(chip, reg, 1, &val, 1);
 392
 393         return;
 394 }
 395
 396 #endif  /* CONFIG_HARD_I2C */