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 DECLARE_GLOBAL_DATA_PTR;
  27
  28 #ifdef CONFIG_HARD_I2C
  29
  30 #include <mpc5xxx.h>
  31 #include <i2c.h>
  32
  33 #if (CFG_I2C_MODULE == 2)
  34 #define I2C_BASE        MPC5XXX_I2C2
  35 #elif (CFG_I2C_MODULE == 1)
  36 #define I2C_BASE        MPC5XXX_I2C1
  37 #else
  38 #error CFG_I2C_MODULE is not properly configured
  39 #endif
  40
  41 #define I2C_TIMEOUT     100
  42 #define I2C_RETRIES     3
  43
  44 struct mpc5xxx_i2c_tap {
  45         int scl2tap;
  46         int tap2tap;
  47 };
  48
  49 static int  mpc_reg_in    (volatile u32 *reg);
  50 static void mpc_reg_out   (volatile u32 *reg, int val, int mask);
  51 static int  wait_for_bb   (void);
  52 static int  wait_for_pin  (int *status);
  53 static int  do_address    (uchar chip, char rdwr_flag);
  54 static int  send_bytes    (uchar chip, char *buf, int len);
  55 static int  receive_bytes (uchar chip, char *buf, int len);
  56 static int  mpc_get_fdr   (int);
  57
  58 static int mpc_reg_in(volatile u32 *reg)
  59 {
  60         int ret = *reg >> 24;
  61         __asm__ __volatile__ ("eieio");
  62         return ret;
  63 }
  64
  65 static void mpc_reg_out(volatile u32 *reg, int val, int mask)
  66 {
  67         int tmp;
  68
  69         if (!mask) {
  70                 *reg = val << 24;
  71         } else {
  72                 tmp = mpc_reg_in(reg);
  73                 *reg = ((tmp & ~mask) | (val & mask)) << 24;
  74         }
  75         __asm__ __volatile__ ("eieio");
  76
  77         return;
  78 }
  79
  80 static int wait_for_bb(void)
  81 {
  82         struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
  83         int                 timeout = I2C_TIMEOUT;
  84         int                 status;
  85
  86         status = mpc_reg_in(&regs->msr);
  87
  88         while (timeout-- && (status & I2C_BB)) {
  89 #if 1
  90                 volatile int temp;
  91                 mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
  92                 temp = mpc_reg_in(&regs->mdr);
  93                 mpc_reg_out(&regs->mcr, 0, I2C_STA);
  94                 mpc_reg_out(&regs->mcr, 0, 0);
  95                 mpc_reg_out(&regs->mcr, I2C_EN, 0);
  96 #endif
  97                 udelay(1000);
  98                 status = mpc_reg_in(&regs->msr);
  99         }
 100
 101         return (status & I2C_BB);
 102 }
 103
 104 static int wait_for_pin(int *status)
 105 {
 106         struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
 107         int                 timeout = I2C_TIMEOUT;
 108
 109         *status = mpc_reg_in(&regs->msr);
 110
 111         while (timeout-- && !(*status & I2C_IF)) {
 112                 udelay(1000);
 113                 *status = mpc_reg_in(&regs->msr);
 114         }
 115
 116         if (!(*status & I2C_IF)) {
 117                 return -1;
 118         }
 119
 120         mpc_reg_out(&regs->msr, 0, I2C_IF);
 121
 122         return 0;
 123 }
 124
 125 static int do_address(uchar chip, char rdwr_flag)
 126 {
 127         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 128         int                 status;
 129
 130         chip <<= 1;
 131
 132         if (rdwr_flag) {
 133                 chip |= 1;
 134         }
 135
 136         mpc_reg_out(&regs->mcr, I2C_TX, I2C_TX);
 137         mpc_reg_out(&regs->mdr, chip, 0);
 138
 139         if (wait_for_pin(&status)) {
 140                 return -2;
 141         }
 142
 143         if (status & I2C_RXAK) {
 144                 return -3;
 145         }
 146
 147         return 0;
 148 }
 149
 150 static int send_bytes(uchar chip, char *buf, int len)
 151 {
 152         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 153         int                 wrcount;
 154         int                 status;
 155
 156         for (wrcount = 0; wrcount < len; ++wrcount) {
 157
 158                 mpc_reg_out(&regs->mdr, buf[wrcount], 0);
 159
 160                 if (wait_for_pin(&status)) {
 161                         break;
 162                 }
 163
 164                 if (status & I2C_RXAK) {
 165                         break;
 166                 }
 167
 168         }
 169
 170         return !(wrcount == len);
 171 }
 172
 173 static int receive_bytes(uchar chip, char *buf, int len)
 174 {
 175         struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
 176         int                 dummy   = 1;
 177         int                 rdcount = 0;
 178         int                 status;
 179         int                 i;
 180
 181         mpc_reg_out(&regs->mcr, 0, I2C_TX);
 182
 183         for (i = 0; i < len; ++i) {
 184                 buf[rdcount] = mpc_reg_in(&regs->mdr);
 185
 186                 if (dummy) {
 187                         dummy = 0;
 188                 } else {
 189                         rdcount++;
 190                 }
 191
 192
 193                 if (wait_for_pin(&status)) {
 194                         return -4;
 195                 }
 196         }
 197
 198         mpc_reg_out(&regs->mcr, I2C_TXAK, I2C_TXAK);
 199         buf[rdcount++] = mpc_reg_in(&regs->mdr);
 200
 201         if (wait_for_pin(&status)) {
 202                 return -5;
 203         }
 204
 205         mpc_reg_out(&regs->mcr, 0, I2C_TXAK);
 206
 207         return 0;
 208 }
 209
 210 /**************** I2C API ****************/
 211
 212 void i2c_init(int speed, int saddr)
 213 {
 214         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 215
 216         mpc_reg_out(&regs->mcr, 0, 0);
 217         mpc_reg_out(&regs->madr, saddr << 1, 0);
 218
 219         /* Set clock
 220          */
 221         mpc_reg_out(&regs->mfdr, mpc_get_fdr(speed), 0);
 222
 223         /* Enable module
 224          */
 225         mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
 226         mpc_reg_out(&regs->msr, 0, I2C_IF);
 227
 228         return;
 229 }
 230
 231 static int mpc_get_fdr(int speed)
 232 {
 233         static int fdr = -1;
 234
 235         if (fdr == -1) {
 236                 ulong best_speed = 0;
 237                 ulong divider;
 238                 ulong ipb, scl;
 239                 ulong bestmatch = 0xffffffffUL;
 240                 int best_i = 0, best_j = 0, i, j;
 241                 int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8};
 242                 struct mpc5xxx_i2c_tap scltap[] = {
 243                         {4, 1},
 244                         {4, 2},
 245                         {6, 4},
 246                         {6, 8},
 247                         {14, 16},
 248                         {30, 32},
 249                         {62, 64},
 250                         {126, 128}
 251                 };
 252
 253                 ipb = gd->ipb_clk;
 254                 for (i = 7; i >= 0; i--) {
 255                         for (j = 7; j >= 0; j--) {
 256                                 scl = 2 * (scltap[j].scl2tap +
 257                                         (SCL_Tap[i] - 1) * scltap[j].tap2tap + 2);
 258                                 if (ipb <= speed*scl) {
 259                                         if ((speed*scl - ipb) < bestmatch) {
 260                                                 bestmatch = speed*scl - ipb;
 261                                                 best_i = i;
 262                                                 best_j = j;
 263                                                 best_speed = ipb/scl;
 264                                         }
 265                                 }
 266                         }
 267                 }
 268                 divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2);
 269                 if (gd->flags & GD_FLG_RELOC) {
 270                         fdr = divider;
 271                 } else {
 272                         printf("%ld kHz, ", best_speed / 1000);
 273                         return divider;
 274                 }
 275         }
 276
 277         return fdr;
 278 }
 279
 280 int i2c_probe(uchar chip)
 281 {
 282         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 283         int                 i;
 284
 285         for (i = 0; i < I2C_RETRIES; i++) {
 286                 mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 287
 288                 if (! do_address(chip, 0)) {
 289                         mpc_reg_out(&regs->mcr, 0, I2C_STA);
 290                         udelay(500);
 291                         break;
 292                 }
 293
 294                 mpc_reg_out(&regs->mcr, 0, I2C_STA);
 295                 udelay(500);
 296         }
 297
 298         return (i == I2C_RETRIES);
 299 }
 300
 301 int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
 302 {
 303         char                xaddr[4];
 304         struct mpc5xxx_i2c * regs        = (struct mpc5xxx_i2c *)I2C_BASE;
 305         int                  ret         = -1;
 306
 307         xaddr[0] = (addr >> 24) & 0xFF;
 308         xaddr[1] = (addr >> 16) & 0xFF;
 309         xaddr[2] = (addr >>  8) & 0xFF;
 310         xaddr[3] =  addr        & 0xFF;
 311
 312         if (wait_for_bb()) {
 313                 printf("i2c_read: bus is busy\n");
 314                 goto Done;
 315         }
 316
 317         mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 318         if (do_address(chip, 0)) {
 319                 printf("i2c_read: failed to address chip\n");
 320                 goto Done;
 321         }
 322
 323         if (send_bytes(chip, &xaddr[4-alen], alen)) {
 324                 printf("i2c_read: send_bytes failed\n");
 325                 goto Done;
 326         }
 327
 328         mpc_reg_out(&regs->mcr, I2C_RSTA, I2C_RSTA);
 329         if (do_address(chip, 1)) {
 330                 printf("i2c_read: failed to address chip\n");
 331                 goto Done;
 332         }
 333
 334         if (receive_bytes(chip, (char *)buf, len)) {
 335                 printf("i2c_read: receive_bytes failed\n");
 336                 goto Done;
 337         }
 338
 339         ret = 0;
 340 Done:
 341         mpc_reg_out(&regs->mcr, 0, I2C_STA);
 342         return ret;
 343 }
 344
 345 int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
 346 {
 347         char               xaddr[4];
 348         struct mpc5xxx_i2c *regs        = (struct mpc5xxx_i2c *)I2C_BASE;
 349         int                 ret         = -1;
 350
 351         xaddr[0] = (addr >> 24) & 0xFF;
 352         xaddr[1] = (addr >> 16) & 0xFF;
 353         xaddr[2] = (addr >>  8) & 0xFF;
 354         xaddr[3] =  addr        & 0xFF;
 355
 356         if (wait_for_bb()) {
 357                 printf("i2c_write: bus is busy\n");
 358                 goto Done;
 359         }
 360
 361         mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 362         if (do_address(chip, 0)) {
 363                 printf("i2c_write: failed to address chip\n");
 364                 goto Done;
 365         }
 366
 367         if (send_bytes(chip, &xaddr[4-alen], alen)) {
 368                 printf("i2c_write: send_bytes failed\n");
 369                 goto Done;
 370         }
 371
 372         if (send_bytes(chip, (char *)buf, len)) {
 373                 printf("i2c_write: send_bytes failed\n");
 374                 goto Done;
 375         }
 376
 377         ret = 0;
 378 Done:
 379         mpc_reg_out(&regs->mcr, 0, I2C_STA);
 380         return ret;
 381 }
 382
 383 uchar i2c_reg_read(uchar chip, uchar reg)
 384 {
 385         uchar buf;
 386
 387         i2c_read(chip, reg, 1, &buf, 1);
 388
 389         return buf;
 390 }
 391
 392 void i2c_reg_write(uchar chip, uchar reg, uchar val)
 393 {
 394         i2c_write(chip, reg, 1, &val, 1);
 395
 396         return;
 397 }
 398
 399 #endif  /* CONFIG_HARD_I2C */