arch/ppc/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 (CONFIG_SYS_I2C_MODULE == 2)
  34 #define I2C_BASE        MPC5XXX_I2C2
  35 #elif (CONFIG_SYS_I2C_MODULE == 1)
  36 #define I2C_BASE        MPC5XXX_I2C1
  37 #else
  38 #error CONFIG_SYS_I2C_MODULE is not properly configured
  39 #endif
  40
  41 #define I2C_TIMEOUT     6667
  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(15);
  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(15);
 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 #if defined(CONFIG_SYS_I2C_INIT_MPC5XXX)
 211
 212 #define FDR510(x) (u8) (((x & 0x20) >> 3) | (x & 0x3))
 213 #define FDR432(x) (u8) ((x & 0x1C) >> 2)
 214 /*
 215  * Reset any i2c devices that may have been interrupted during a system reset.
 216  * Normally this would be accomplished by clocking the line until SCL and SDA
 217  * are released and then sending a start condtiion (From an Atmel datasheet).
 218  * There is no direct access to the i2c pins so instead create start commands
 219  * through the i2c interface.  Send a start command then delay for the SDA Hold
 220  * time, repeat this by disabling/enabling the bus a total of 9 times.
 221  */
 222 static void send_reset(void)
 223 {
 224         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 225         int i;
 226         u32 delay;
 227         u8 fdr;
 228         int SDA_Tap[] = { 3, 3, 4, 4, 1, 1, 2, 2};
 229         struct mpc5xxx_i2c_tap scltap[] = {
 230                 {4, 1},
 231                 {4, 2},
 232                 {6, 4},
 233                 {6, 8},
 234                 {14, 16},
 235                 {30, 32},
 236                 {62, 64},
 237                 {126, 128}
 238         };
 239
 240         fdr = (u8)mpc_reg_in(&regs->mfdr);
 241
 242         delay = scltap[FDR432(fdr)].scl2tap + ((SDA_Tap[FDR510(fdr)] - 1) * \
 243                 scltap[FDR432(fdr)].tap2tap) + 3;
 244
 245         for (i = 0; i < 9; i++) {
 246                 mpc_reg_out(&regs->mcr, I2C_EN|I2C_STA|I2C_TX, I2C_INIT_MASK);
 247                 udelay(delay);
 248                 mpc_reg_out(&regs->mcr, 0, I2C_INIT_MASK);
 249                 udelay(delay);
 250         }
 251
 252         mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
 253 }
 254 #endif /* CONFIG_SYS_I2c_INIT_MPC5XXX */
 255
 256 /**************** I2C API ****************/
 257
 258 void i2c_init(int speed, int saddr)
 259 {
 260         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 261
 262         mpc_reg_out(&regs->mcr, 0, 0);
 263         mpc_reg_out(&regs->madr, saddr << 1, 0);
 264
 265         /* Set clock
 266          */
 267         mpc_reg_out(&regs->mfdr, mpc_get_fdr(speed), 0);
 268
 269         /* Enable module
 270          */
 271         mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
 272         mpc_reg_out(&regs->msr, 0, I2C_IF);
 273
 274 #if defined(CONFIG_SYS_I2C_INIT_MPC5XXX)
 275         send_reset();
 276 #endif
 277         return;
 278 }
 279
 280 static int mpc_get_fdr(int speed)
 281 {
 282         static int fdr = -1;
 283
 284         if (fdr == -1) {
 285                 ulong best_speed = 0;
 286                 ulong divider;
 287                 ulong ipb, scl;
 288                 ulong bestmatch = 0xffffffffUL;
 289                 int best_i = 0, best_j = 0, i, j;
 290                 int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8};
 291                 struct mpc5xxx_i2c_tap scltap[] = {
 292                         {4, 1},
 293                         {4, 2},
 294                         {6, 4},
 295                         {6, 8},
 296                         {14, 16},
 297                         {30, 32},
 298                         {62, 64},
 299                         {126, 128}
 300                 };
 301
 302                 ipb = gd->ipb_clk;
 303                 for (i = 7; i >= 0; i--) {
 304                         for (j = 7; j >= 0; j--) {
 305                                 scl = 2 * (scltap[j].scl2tap +
 306                                         (SCL_Tap[i] - 1) * scltap[j].tap2tap + 2);
 307                                 if (ipb <= speed*scl) {
 308                                         if ((speed*scl - ipb) < bestmatch) {
 309                                                 bestmatch = speed*scl - ipb;
 310                                                 best_i = i;
 311                                                 best_j = j;
 312                                                 best_speed = ipb/scl;
 313                                         }
 314                                 }
 315                         }
 316                 }
 317                 divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2);
 318                 if (gd->flags & GD_FLG_RELOC) {
 319                         fdr = divider;
 320                 } else {
 321                         if (gd->have_console)
 322                                 printf("%ld kHz, ", best_speed / 1000);
 323                         return divider;
 324                 }
 325         }
 326
 327         return fdr;
 328 }
 329
 330 int i2c_probe(uchar chip)
 331 {
 332         struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
 333         int                 i;
 334
 335         for (i = 0; i < I2C_RETRIES; i++) {
 336                 mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 337
 338                 if (! do_address(chip, 0)) {
 339                         mpc_reg_out(&regs->mcr, 0, I2C_STA);
 340                         udelay(500);
 341                         break;
 342                 }
 343
 344                 mpc_reg_out(&regs->mcr, 0, I2C_STA);
 345                 udelay(500);
 346         }
 347
 348         return (i == I2C_RETRIES);
 349 }
 350
 351 int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
 352 {
 353         char                xaddr[4];
 354         struct mpc5xxx_i2c * regs        = (struct mpc5xxx_i2c *)I2C_BASE;
 355         int                  ret         = -1;
 356
 357         xaddr[0] = (addr >> 24) & 0xFF;
 358         xaddr[1] = (addr >> 16) & 0xFF;
 359         xaddr[2] = (addr >>  8) & 0xFF;
 360         xaddr[3] =  addr        & 0xFF;
 361
 362         if (wait_for_bb()) {
 363                 if (gd->have_console)
 364                         printf("i2c_read: bus is busy\n");
 365                 goto Done;
 366         }
 367
 368         mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 369         if (do_address(chip, 0)) {
 370                 if (gd->have_console)
 371                         printf("i2c_read: failed to address chip\n");
 372                 goto Done;
 373         }
 374
 375         if (send_bytes(chip, &xaddr[4-alen], alen)) {
 376                 if (gd->have_console)
 377                         printf("i2c_read: send_bytes failed\n");
 378                 goto Done;
 379         }
 380
 381         mpc_reg_out(&regs->mcr, I2C_RSTA, I2C_RSTA);
 382         if (do_address(chip, 1)) {
 383                 if (gd->have_console)
 384                         printf("i2c_read: failed to address chip\n");
 385                 goto Done;
 386         }
 387
 388         if (receive_bytes(chip, (char *)buf, len)) {
 389                 if (gd->have_console)
 390                         printf("i2c_read: receive_bytes failed\n");
 391                 goto Done;
 392         }
 393
 394         ret = 0;
 395 Done:
 396         mpc_reg_out(&regs->mcr, 0, I2C_STA);
 397         return ret;
 398 }
 399
 400 int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
 401 {
 402         char               xaddr[4];
 403         struct mpc5xxx_i2c *regs        = (struct mpc5xxx_i2c *)I2C_BASE;
 404         int                 ret         = -1;
 405
 406         xaddr[0] = (addr >> 24) & 0xFF;
 407         xaddr[1] = (addr >> 16) & 0xFF;
 408         xaddr[2] = (addr >>  8) & 0xFF;
 409         xaddr[3] =  addr        & 0xFF;
 410
 411         if (wait_for_bb()) {
 412                 if (gd->have_console)
 413                         printf("i2c_write: bus is busy\n");
 414                 goto Done;
 415         }
 416
 417         mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
 418         if (do_address(chip, 0)) {
 419                 if (gd->have_console)
 420                         printf("i2c_write: failed to address chip\n");
 421                 goto Done;
 422         }
 423
 424         if (send_bytes(chip, &xaddr[4-alen], alen)) {
 425                 if (gd->have_console)
 426                         printf("i2c_write: send_bytes failed\n");
 427                 goto Done;
 428         }
 429
 430         if (send_bytes(chip, (char *)buf, len)) {
 431                 if (gd->have_console)
 432                         printf("i2c_write: send_bytes failed\n");
 433                 goto Done;
 434         }
 435
 436         ret = 0;
 437 Done:
 438         mpc_reg_out(&regs->mcr, 0, I2C_STA);
 439         return ret;
 440 }
 441
 442 #endif  /* CONFIG_HARD_I2C */