cpu/mpc8220/i2c.c

   1 /*
   2  * (C) Copyright 2004, Freescale, Inc
   3  * TsiChung Liew, Tsi-Chung.Liew@freescale.com.
   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 <mpc8220.h>
  29 #include <i2c.h>
  30
  31 typedef struct mpc8220_i2c {
  32         volatile u32 adr;       /* I2Cn + 0x00 */
  33         volatile u32 fdr;       /* I2Cn + 0x04 */
  34         volatile u32 cr;        /* I2Cn + 0x08 */
  35         volatile u32 sr;        /* I2Cn + 0x0C */
  36         volatile u32 dr;        /* I2Cn + 0x10 */
  37 } i2c_t;
  38
  39 /* I2Cn control register bits */
  40 #define I2C_EN      0x80
  41 #define I2C_IEN     0x40
  42 #define I2C_STA     0x20
  43 #define I2C_TX      0x10
  44 #define I2C_TXAK    0x08
  45 #define I2C_RSTA    0x04
  46 #define I2C_INIT_MASK   (I2C_EN | I2C_STA | I2C_TX | I2C_RSTA)
  47
  48 /* I2Cn status register bits */
  49 #define I2C_CF      0x80
  50 #define I2C_AAS     0x40
  51 #define I2C_BB      0x20
  52 #define I2C_AL      0x10
  53 #define I2C_SRW     0x04
  54 #define I2C_IF      0x02
  55 #define I2C_RXAK    0x01
  56
  57 #define I2C_TIMEOUT 100
  58 #define I2C_RETRIES 1
  59
  60 struct mpc8220_i2c_tap {
  61         int scl2tap;
  62         int tap2tap;
  63 };
  64
  65 static int mpc_reg_in (volatile u32 * reg);
  66 static void mpc_reg_out (volatile u32 * reg, int val, int mask);
  67 static int wait_for_bb (void);
  68 static int wait_for_pin (int *status);
  69 static int do_address (uchar chip, char rdwr_flag);
  70 static int send_bytes (uchar chip, char *buf, int len);
  71 static int receive_bytes (uchar chip, char *buf, int len);
  72 static int mpc_get_fdr (int);
  73
  74 static int mpc_reg_in (volatile u32 * reg)
  75 {
  76         int ret;
  77         ret = *reg >> 24;
  78         __asm__ __volatile__ ("eieio");
  79         return ret;
  80 }
  81
  82 static void mpc_reg_out (volatile u32 * reg, int val, int mask)
  83 {
  84         int tmp;
  85
  86         if (!mask) {
  87                 *reg = val << 24;
  88         } else {
  89                 tmp = mpc_reg_in (reg);
  90                 *reg = ((tmp & ~mask) | (val & mask)) << 24;
  91         }
  92         __asm__ __volatile__ ("eieio");
  93
  94         return;
  95 }
  96
  97 static int wait_for_bb (void)
  98 {
  99         i2c_t *regs = (i2c_t *) MMAP_I2C;
 100         int timeout = I2C_TIMEOUT;
 101         int status;
 102
 103         status = mpc_reg_in (&regs->sr);
 104
 105         while (timeout-- && (status & I2C_BB)) {
 106 #if 1
 107                 volatile int temp;
 108
 109                 mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
 110                 temp = mpc_reg_in (&regs->dr);
 111                 mpc_reg_out (&regs->cr, 0, I2C_STA);
 112                 mpc_reg_out (&regs->cr, 0, 0);
 113                 mpc_reg_out (&regs->cr, I2C_EN, 0);
 114 #endif
 115                 udelay (1000);
 116                 status = mpc_reg_in (&regs->sr);
 117         }
 118
 119         return (status & I2C_BB);
 120 }
 121
 122 static int wait_for_pin (int *status)
 123 {
 124         i2c_t *regs = (i2c_t *) MMAP_I2C;
 125         int timeout = I2C_TIMEOUT;
 126
 127         *status = mpc_reg_in (&regs->sr);
 128
 129         while (timeout-- && !(*status & I2C_IF)) {
 130                 udelay (1000);
 131                 *status = mpc_reg_in (&regs->sr);
 132         }
 133
 134         if (!(*status & I2C_IF)) {
 135                 return -1;
 136         }
 137
 138         mpc_reg_out (&regs->sr, 0, I2C_IF);
 139         return 0;
 140 }
 141
 142 static int do_address (uchar chip, char rdwr_flag)
 143 {
 144         i2c_t *regs = (i2c_t *) MMAP_I2C;
 145         int status;
 146
 147         chip <<= 1;
 148
 149         if (rdwr_flag)
 150                 chip |= 1;
 151
 152         mpc_reg_out (&regs->cr, I2C_TX, I2C_TX);
 153         mpc_reg_out (&regs->dr, chip, 0);
 154
 155         if (wait_for_pin (&status))
 156                 return -2;
 157         if (status & I2C_RXAK)
 158                 return -3;
 159         return 0;
 160 }
 161
 162 static int send_bytes (uchar chip, char *buf, int len)
 163 {
 164         i2c_t *regs = (i2c_t *) MMAP_I2C;
 165         int wrcount;
 166         int status;
 167
 168         for (wrcount = 0; wrcount < len; ++wrcount) {
 169
 170                 mpc_reg_out (&regs->dr, buf[wrcount], 0);
 171
 172                 if (wait_for_pin (&status))
 173                         break;
 174
 175                 if (status & I2C_RXAK)
 176                         break;
 177
 178         }
 179
 180         return !(wrcount == len);
 181         return 0;
 182 }
 183
 184 static int receive_bytes (uchar chip, char *buf, int len)
 185 {
 186         i2c_t *regs = (i2c_t *) MMAP_I2C;
 187         int dummy = 1;
 188         int rdcount = 0;
 189         int status;
 190         int i;
 191
 192         mpc_reg_out (&regs->cr, 0, I2C_TX);
 193
 194         for (i = 0; i < len; ++i) {
 195                 buf[rdcount] = mpc_reg_in (&regs->dr);
 196
 197                 if (dummy)
 198                         dummy = 0;
 199                 else
 200                         rdcount++;
 201
 202                 if (wait_for_pin (&status))
 203                         return -4;
 204         }
 205
 206         mpc_reg_out (&regs->cr, I2C_TXAK, I2C_TXAK);
 207         buf[rdcount++] = mpc_reg_in (&regs->dr);
 208
 209         if (wait_for_pin (&status))
 210                 return -5;
 211
 212         mpc_reg_out (&regs->cr, 0, I2C_TXAK);
 213         return 0;
 214 }
 215
 216 /**************** I2C API ****************/
 217
 218 void i2c_init (int speed, int saddr)
 219 {
 220         i2c_t *regs = (i2c_t *) MMAP_I2C;
 221
 222         mpc_reg_out (&regs->cr, 0, 0);
 223         mpc_reg_out (&regs->adr, saddr << 1, 0);
 224
 225         /* Set clock
 226          */
 227         mpc_reg_out (&regs->fdr, mpc_get_fdr (speed), 0);
 228
 229         /* Enable module
 230          */
 231         mpc_reg_out (&regs->cr, I2C_EN, I2C_INIT_MASK);
 232         mpc_reg_out (&regs->sr, 0, I2C_IF);
 233         return;
 234 }
 235
 236 static int mpc_get_fdr (int speed)
 237 {
 238         DECLARE_GLOBAL_DATA_PTR;
 239         static int fdr = -1;
 240
 241         if (fdr == -1) {
 242                 ulong best_speed = 0;
 243                 ulong divider;
 244                 ulong ipb, scl;
 245                 ulong bestmatch = 0xffffffffUL;
 246                 int best_i = 0, best_j = 0, i, j;
 247                 int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8 };
 248                 struct mpc8220_i2c_tap scltap[] = {
 249                         {4, 1},
 250                         {4, 2},
 251                         {6, 4},
 252                         {6, 8},
 253                         {14, 16},
 254                         {30, 32},
 255                         {62, 64},
 256                         {126, 128}
 257                 };
 258
 259                 ipb = gd->bus_clk;
 260                 for (i = 7; i >= 0; i--) {
 261                         for (j = 7; j >= 0; j--) {
 262                                 scl = 2 * (scltap[j].scl2tap +
 263                                            (SCL_Tap[i] -
 264                                             1) * scltap[j].tap2tap + 2);
 265                                 if (ipb <= speed * scl) {
 266                                         if ((speed * scl - ipb) < bestmatch) {
 267                                                 bestmatch = speed * scl - ipb;
 268                                                 best_i = i;
 269                                                 best_j = j;
 270                                                 best_speed = ipb / scl;
 271                                         }
 272                                 }
 273                         }
 274                 }
 275                 divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2);
 276                 if (gd->flags & GD_FLG_RELOC) {
 277                         fdr = divider;
 278                 } else {
 279                         printf ("%ld kHz, ", best_speed / 1000);
 280                         return divider;
 281                 }
 282         }
 283
 284         return fdr;
 285 }
 286
 287 int i2c_probe (uchar chip)
 288 {
 289         i2c_t *regs = (i2c_t *) MMAP_I2C;
 290         int i;
 291
 292         for (i = 0; i < I2C_RETRIES; i++) {
 293                 mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
 294
 295                 if (!do_address (chip, 0)) {
 296                         mpc_reg_out (&regs->cr, 0, I2C_STA);
 297                         break;
 298                 }
 299
 300                 mpc_reg_out (&regs->cr, 0, I2C_STA);
 301                 udelay (50);
 302         }
 303
 304         return (i == I2C_RETRIES);
 305 }
 306
 307 int i2c_read (uchar chip, uint addr, int alen, uchar * buf, int len)
 308 {
 309         uchar xaddr[4];
 310         i2c_t *regs = (i2c_t *) MMAP_I2C;
 311         int ret = -1;
 312
 313         xaddr[0] = (addr >> 24) & 0xFF;
 314         xaddr[1] = (addr >> 16) & 0xFF;
 315         xaddr[2] = (addr >> 8) & 0xFF;
 316         xaddr[3] = addr & 0xFF;
 317
 318         if (wait_for_bb ()) {
 319                 printf ("i2c_read: bus is busy\n");
 320                 goto Done;
 321         }
 322
 323         mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
 324         if (do_address (chip, 0)) {
 325                 printf ("i2c_read: failed to address chip\n");
 326                 goto Done;
 327         }
 328
 329         if (send_bytes (chip, (char *)&xaddr[4 - alen], alen)) {
 330                 printf ("i2c_read: send_bytes failed\n");
 331                 goto Done;
 332         }
 333
 334         mpc_reg_out (&regs->cr, I2C_RSTA, I2C_RSTA);
 335         if (do_address (chip, 1)) {
 336                 printf ("i2c_read: failed to address chip\n");
 337                 goto Done;
 338         }
 339
 340         if (receive_bytes (chip, (char *)buf, len)) {
 341                 printf ("i2c_read: receive_bytes failed\n");
 342                 goto Done;
 343         }
 344
 345         ret = 0;
 346       Done:
 347         mpc_reg_out (&regs->cr, 0, I2C_STA);
 348         return ret;
 349 }
 350
 351 int i2c_write (uchar chip, uint addr, int alen, uchar * buf, int len)
 352 {
 353         uchar xaddr[4];
 354         i2c_t *regs = (i2c_t *) MMAP_I2C;
 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                 printf ("i2c_write: bus is busy\n");
 364                 goto Done;
 365         }
 366
 367         mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
 368         if (do_address (chip, 0)) {
 369                 printf ("i2c_write: failed to address chip\n");
 370                 goto Done;
 371         }
 372
 373         if (send_bytes (chip, (char *)&xaddr[4 - alen], alen)) {
 374                 printf ("i2c_write: send_bytes failed\n");
 375                 goto Done;
 376         }
 377
 378         if (send_bytes (chip, (char *)buf, len)) {
 379                 printf ("i2c_write: send_bytes failed\n");
 380                 goto Done;
 381         }
 382
 383         ret = 0;
 384       Done:
 385         mpc_reg_out (&regs->cr, 0, I2C_STA);
 386         return ret;
 387 }
 388
 389 uchar i2c_reg_read (uchar chip, uchar reg)
 390 {
 391         uchar buf;
 392
 393         i2c_read (chip, reg, 1, &buf, 1);
 394
 395         return buf;
 396 }
 397
 398 void i2c_reg_write (uchar chip, uchar reg, uchar val)
 399 {
 400         i2c_write (chip, reg, 1, &val, 1);
 401
 402         return;
 403 }
 404
 405 #endif /* CONFIG_HARD_I2C */