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 DECLARE_GLOBAL_DATA_PTR;
  27
  28 #ifdef CONFIG_HARD_I2C
  29
  30 #include <mpc8220.h>
  31 #include <i2c.h>
  32
  33 typedef struct mpc8220_i2c {
  34         volatile u32 adr;       /* I2Cn + 0x00 */
  35         volatile u32 fdr;       /* I2Cn + 0x04 */
  36         volatile u32 cr;        /* I2Cn + 0x08 */
  37         volatile u32 sr;        /* I2Cn + 0x0C */
  38         volatile u32 dr;        /* I2Cn + 0x10 */
  39 } i2c_t;
  40
  41 /* I2Cn control register bits */
  42 #define I2C_EN      0x80
  43 #define I2C_IEN     0x40
  44 #define I2C_STA     0x20
  45 #define I2C_TX      0x10
  46 #define I2C_TXAK    0x08
  47 #define I2C_RSTA    0x04
  48 #define I2C_INIT_MASK   (I2C_EN | I2C_STA | I2C_TX | I2C_RSTA)
  49
  50 /* I2Cn status register bits */
  51 #define I2C_CF      0x80
  52 #define I2C_AAS     0x40
  53 #define I2C_BB      0x20
  54 #define I2C_AL      0x10
  55 #define I2C_SRW     0x04
  56 #define I2C_IF      0x02
  57 #define I2C_RXAK    0x01
  58
  59 #define I2C_TIMEOUT 100
  60 #define I2C_RETRIES 1
  61
  62 struct mpc8220_i2c_tap {
  63         int scl2tap;
  64         int tap2tap;
  65 };
  66
  67 static int mpc_reg_in (volatile u32 * reg);
  68 static void mpc_reg_out (volatile u32 * reg, int val, int mask);
  69 static int wait_for_bb (void);
  70 static int wait_for_pin (int *status);
  71 static int do_address (uchar chip, char rdwr_flag);
  72 static int send_bytes (uchar chip, char *buf, int len);
  73 static int receive_bytes (uchar chip, char *buf, int len);
  74 static int mpc_get_fdr (int);
  75
  76 static int mpc_reg_in (volatile u32 * reg)
  77 {
  78         int ret;
  79         ret = *reg >> 24;
  80         __asm__ __volatile__ ("eieio");
  81         return ret;
  82 }
  83
  84 static void mpc_reg_out (volatile u32 * reg, int val, int mask)
  85 {
  86         int tmp;
  87
  88         if (!mask) {
  89                 *reg = val << 24;
  90         } else {
  91                 tmp = mpc_reg_in (reg);
  92                 *reg = ((tmp & ~mask) | (val & mask)) << 24;
  93         }
  94         __asm__ __volatile__ ("eieio");
  95
  96         return;
  97 }
  98
  99 static int wait_for_bb (void)
 100 {
 101         i2c_t *regs = (i2c_t *) MMAP_I2C;
 102         int timeout = I2C_TIMEOUT;
 103         int status;
 104
 105         status = mpc_reg_in (&regs->sr);
 106
 107         while (timeout-- && (status & I2C_BB)) {
 108 #if 1
 109                 volatile int temp;
 110
 111                 mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
 112                 temp = mpc_reg_in (&regs->dr);
 113                 mpc_reg_out (&regs->cr, 0, I2C_STA);
 114                 mpc_reg_out (&regs->cr, 0, 0);
 115                 mpc_reg_out (&regs->cr, I2C_EN, 0);
 116 #endif
 117                 udelay (1000);
 118                 status = mpc_reg_in (&regs->sr);
 119         }
 120
 121         return (status & I2C_BB);
 122 }
 123
 124 static int wait_for_pin (int *status)
 125 {
 126         i2c_t *regs = (i2c_t *) MMAP_I2C;
 127         int timeout = I2C_TIMEOUT;
 128
 129         *status = mpc_reg_in (&regs->sr);
 130
 131         while (timeout-- && !(*status & I2C_IF)) {
 132                 udelay (1000);
 133                 *status = mpc_reg_in (&regs->sr);
 134         }
 135
 136         if (!(*status & I2C_IF)) {
 137                 return -1;
 138         }
 139
 140         mpc_reg_out (&regs->sr, 0, I2C_IF);
 141         return 0;
 142 }
 143
 144 static int do_address (uchar chip, char rdwr_flag)
 145 {
 146         i2c_t *regs = (i2c_t *) MMAP_I2C;
 147         int status;
 148
 149         chip <<= 1;
 150
 151         if (rdwr_flag)
 152                 chip |= 1;
 153
 154         mpc_reg_out (&regs->cr, I2C_TX, I2C_TX);
 155         mpc_reg_out (&regs->dr, chip, 0);
 156
 157         if (wait_for_pin (&status))
 158                 return -2;
 159         if (status & I2C_RXAK)
 160                 return -3;
 161         return 0;
 162 }
 163
 164 static int send_bytes (uchar chip, char *buf, int len)
 165 {
 166         i2c_t *regs = (i2c_t *) MMAP_I2C;
 167         int wrcount;
 168         int status;
 169
 170         for (wrcount = 0; wrcount < len; ++wrcount) {
 171
 172                 mpc_reg_out (&regs->dr, buf[wrcount], 0);
 173
 174                 if (wait_for_pin (&status))
 175                         break;
 176
 177                 if (status & I2C_RXAK)
 178                         break;
 179
 180         }
 181
 182         return !(wrcount == len);
 183         return 0;
 184 }
 185
 186 static int receive_bytes (uchar chip, char *buf, int len)
 187 {
 188         i2c_t *regs = (i2c_t *) MMAP_I2C;
 189         int dummy = 1;
 190         int rdcount = 0;
 191         int status;
 192         int i;
 193
 194         mpc_reg_out (&regs->cr, 0, I2C_TX);
 195
 196         for (i = 0; i < len; ++i) {
 197                 buf[rdcount] = mpc_reg_in (&regs->dr);
 198
 199                 if (dummy)
 200                         dummy = 0;
 201                 else
 202                         rdcount++;
 203
 204                 if (wait_for_pin (&status))
 205                         return -4;
 206         }
 207
 208         mpc_reg_out (&regs->cr, I2C_TXAK, I2C_TXAK);
 209         buf[rdcount++] = mpc_reg_in (&regs->dr);
 210
 211         if (wait_for_pin (&status))
 212                 return -5;
 213
 214         mpc_reg_out (&regs->cr, 0, I2C_TXAK);
 215         return 0;
 216 }
 217
 218 /**************** I2C API ****************/
 219
 220 void i2c_init (int speed, int saddr)
 221 {
 222         i2c_t *regs = (i2c_t *) MMAP_I2C;
 223
 224         mpc_reg_out (&regs->cr, 0, 0);
 225         mpc_reg_out (&regs->adr, saddr << 1, 0);
 226
 227         /* Set clock
 228          */
 229         mpc_reg_out (&regs->fdr, mpc_get_fdr (speed), 0);
 230
 231         /* Enable module
 232          */
 233         mpc_reg_out (&regs->cr, I2C_EN, I2C_INIT_MASK);
 234         mpc_reg_out (&regs->sr, 0, I2C_IF);
 235         return;
 236 }
 237
 238 static int mpc_get_fdr (int speed)
 239 {
 240         static int fdr = -1;
 241
 242         if (fdr == -1) {
 243                 ulong best_speed = 0;
 244                 ulong divider;
 245                 ulong ipb, scl;
 246                 ulong bestmatch = 0xffffffffUL;
 247                 int best_i = 0, best_j = 0, i, j;
 248                 int SCL_Tap[] = { 9, 10, 12, 15, 5, 6, 7, 8 };
 249                 struct mpc8220_i2c_tap scltap[] = {
 250                         {4, 1},
 251                         {4, 2},
 252                         {6, 4},
 253                         {6, 8},
 254                         {14, 16},
 255                         {30, 32},
 256                         {62, 64},
 257                         {126, 128}
 258                 };
 259
 260                 ipb = gd->bus_clk;
 261                 for (i = 7; i >= 0; i--) {
 262                         for (j = 7; j >= 0; j--) {
 263                                 scl = 2 * (scltap[j].scl2tap +
 264                                            (SCL_Tap[i] -
 265                                             1) * scltap[j].tap2tap + 2);
 266                                 if (ipb <= speed * scl) {
 267                                         if ((speed * scl - ipb) < bestmatch) {
 268                                                 bestmatch = speed * scl - ipb;
 269                                                 best_i = i;
 270                                                 best_j = j;
 271                                                 best_speed = ipb / scl;
 272                                         }
 273                                 }
 274                         }
 275                 }
 276                 divider = (best_i & 3) | ((best_i & 4) << 3) | (best_j << 2);
 277                 if (gd->flags & GD_FLG_RELOC) {
 278                         fdr = divider;
 279                 } else {
 280                         printf ("%ld kHz, ", best_speed / 1000);
 281                         return divider;
 282                 }
 283         }
 284
 285         return fdr;
 286 }
 287
 288 int i2c_probe (uchar chip)
 289 {
 290         i2c_t *regs = (i2c_t *) MMAP_I2C;
 291         int i;
 292
 293         for (i = 0; i < I2C_RETRIES; i++) {
 294                 mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
 295
 296                 if (!do_address (chip, 0)) {
 297                         mpc_reg_out (&regs->cr, 0, I2C_STA);
 298                         break;
 299                 }
 300
 301                 mpc_reg_out (&regs->cr, 0, I2C_STA);
 302                 udelay (50);
 303         }
 304
 305         return (i == I2C_RETRIES);
 306 }
 307
 308 int i2c_read (uchar chip, uint addr, int alen, uchar * buf, int len)
 309 {
 310         uchar xaddr[4];
 311         i2c_t *regs = (i2c_t *) MMAP_I2C;
 312         int ret = -1;
 313
 314         xaddr[0] = (addr >> 24) & 0xFF;
 315         xaddr[1] = (addr >> 16) & 0xFF;
 316         xaddr[2] = (addr >> 8) & 0xFF;
 317         xaddr[3] = addr & 0xFF;
 318
 319         if (wait_for_bb ()) {
 320                 printf ("i2c_read: bus is busy\n");
 321                 goto Done;
 322         }
 323
 324         mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
 325         if (do_address (chip, 0)) {
 326                 printf ("i2c_read: failed to address chip\n");
 327                 goto Done;
 328         }
 329
 330         if (send_bytes (chip, (char *)&xaddr[4 - alen], alen)) {
 331                 printf ("i2c_read: send_bytes failed\n");
 332                 goto Done;
 333         }
 334
 335         mpc_reg_out (&regs->cr, I2C_RSTA, I2C_RSTA);
 336         if (do_address (chip, 1)) {
 337                 printf ("i2c_read: failed to address chip\n");
 338                 goto Done;
 339         }
 340
 341         if (receive_bytes (chip, (char *)buf, len)) {
 342                 printf ("i2c_read: receive_bytes failed\n");
 343                 goto Done;
 344         }
 345
 346         ret = 0;
 347       Done:
 348         mpc_reg_out (&regs->cr, 0, I2C_STA);
 349         return ret;
 350 }
 351
 352 int i2c_write (uchar chip, uint addr, int alen, uchar * buf, int len)
 353 {
 354         uchar xaddr[4];
 355         i2c_t *regs = (i2c_t *) MMAP_I2C;
 356         int ret = -1;
 357
 358         xaddr[0] = (addr >> 24) & 0xFF;
 359         xaddr[1] = (addr >> 16) & 0xFF;
 360         xaddr[2] = (addr >> 8) & 0xFF;
 361         xaddr[3] = addr & 0xFF;
 362
 363         if (wait_for_bb ()) {
 364                 printf ("i2c_write: bus is busy\n");
 365                 goto Done;
 366         }
 367
 368         mpc_reg_out (&regs->cr, I2C_STA, I2C_STA);
 369         if (do_address (chip, 0)) {
 370                 printf ("i2c_write: failed to address chip\n");
 371                 goto Done;
 372         }
 373
 374         if (send_bytes (chip, (char *)&xaddr[4 - alen], alen)) {
 375                 printf ("i2c_write: send_bytes failed\n");
 376                 goto Done;
 377         }
 378
 379         if (send_bytes (chip, (char *)buf, len)) {
 380                 printf ("i2c_write: send_bytes failed\n");
 381                 goto Done;
 382         }
 383
 384         ret = 0;
 385       Done:
 386         mpc_reg_out (&regs->cr, 0, I2C_STA);
 387         return ret;
 388 }
 389
 390 uchar i2c_reg_read (uchar chip, uchar reg)
 391 {
 392         uchar buf;
 393
 394         i2c_read (chip, reg, 1, &buf, 1);
 395
 396         return buf;
 397 }
 398
 399 void i2c_reg_write (uchar chip, uchar reg, uchar val)
 400 {
 401         i2c_write (chip, reg, 1, &val, 1);
 402
 403         return;
 404 }
 405
 406 #endif /* CONFIG_HARD_I2C */