drivers/i2c/s3c24x0_i2c.c

   1 /*
   2  * (C) Copyright 2002
   3  * David Mueller, ELSOFT AG, d.mueller@elsoft.ch
   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 /* This code should work for both the S3C2400 and the S3C2410
  25  * as they seem to have the same I2C controller inside.
  26  * The different address mapping is handled by the s3c24xx.h files below.
  27  */
  28
  29 #include <common.h>
  30 #include <fdtdec.h>
  31 #if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
  32 #include <asm/arch/clk.h>
  33 #include <asm/arch/cpu.h>
  34 #include <asm/arch/pinmux.h>
  35 #else
  36 #include <asm/arch/s3c24x0_cpu.h>
  37 #endif
  38 #include <asm/io.h>
  39 #include <i2c.h>
  40 #include "s3c24x0_i2c.h"
  41
  42 #ifdef CONFIG_HARD_I2C
  43
  44 #define I2C_WRITE       0
  45 #define I2C_READ        1
  46
  47 #define I2C_OK          0
  48 #define I2C_NOK         1
  49 #define I2C_NACK        2
  50 #define I2C_NOK_LA      3       /* Lost arbitration */
  51 #define I2C_NOK_TOUT    4       /* time out */
  52
  53 #define I2CSTAT_BSY     0x20    /* Busy bit */
  54 #define I2CSTAT_NACK    0x01    /* Nack bit */
  55 #define I2CCON_ACKGEN   0x80    /* Acknowledge generation */
  56 #define I2CCON_IRPND    0x10    /* Interrupt pending bit */
  57 #define I2C_MODE_MT     0xC0    /* Master Transmit Mode */
  58 #define I2C_MODE_MR     0x80    /* Master Receive Mode */
  59 #define I2C_START_STOP  0x20    /* START / STOP */
  60 #define I2C_TXRX_ENA    0x10    /* I2C Tx/Rx enable */
  61
  62 #define I2C_TIMEOUT 1           /* 1 second */
  63
  64
  65 /*
  66  * For SPL boot some boards need i2c before SDRAM is initialised so force
  67  * variables to live in SRAM
  68  */
  69 static unsigned int g_current_bus __attribute__((section(".data")));
  70 #ifdef CONFIG_OF_CONTROL
  71 static int i2c_busses __attribute__((section(".data")));
  72 static struct s3c24x0_i2c_bus i2c_bus[CONFIG_MAX_I2C_NUM]
  73                         __attribute__((section(".data")));
  74 #endif
  75
  76 #if !(defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
  77 static int GetI2CSDA(void)
  78 {
  79         struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
  80
  81 #ifdef CONFIG_S3C2410
  82         return (readl(&gpio->gpedat) & 0x8000) >> 15;
  83 #endif
  84 #ifdef CONFIG_S3C2400
  85         return (readl(&gpio->pgdat) & 0x0020) >> 5;
  86 #endif
  87 }
  88
  89 #if 0
  90 static void SetI2CSDA(int x)
  91 {
  92         rGPEDAT = (rGPEDAT & ~0x8000) | (x & 1) << 15;
  93 }
  94 #endif
  95
  96 static void SetI2CSCL(int x)
  97 {
  98         struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
  99
 100 #ifdef CONFIG_S3C2410
 101         writel((readl(&gpio->gpedat) & ~0x4000) |
 102                                         (x & 1) << 14, &gpio->gpedat);
 103 #endif
 104 #ifdef CONFIG_S3C2400
 105         writel((readl(&gpio->pgdat) & ~0x0040) | (x & 1) << 6, &gpio->pgdat);
 106 #endif
 107 }
 108 #endif
 109
 110 static int WaitForXfer(struct s3c24x0_i2c *i2c)
 111 {
 112         int i;
 113
 114         i = I2C_TIMEOUT * 10000;
 115         while (!(readl(&i2c->iiccon) & I2CCON_IRPND) && (i > 0)) {
 116                 udelay(100);
 117                 i--;
 118         }
 119
 120         return (readl(&i2c->iiccon) & I2CCON_IRPND) ? I2C_OK : I2C_NOK_TOUT;
 121 }
 122
 123 static int IsACK(struct s3c24x0_i2c *i2c)
 124 {
 125         return !(readl(&i2c->iicstat) & I2CSTAT_NACK);
 126 }
 127
 128 static void ReadWriteByte(struct s3c24x0_i2c *i2c)
 129 {
 130         writel(readl(&i2c->iiccon) & ~I2CCON_IRPND, &i2c->iiccon);
 131 }
 132
 133 static struct s3c24x0_i2c *get_base_i2c(void)
 134 {
 135 #ifdef CONFIG_EXYNOS4
 136         struct s3c24x0_i2c *i2c = (struct s3c24x0_i2c *)(samsung_get_base_i2c()
 137                                                         + (EXYNOS4_I2C_SPACING
 138                                                         * g_current_bus));
 139         return i2c;
 140 #elif defined CONFIG_EXYNOS5
 141         struct s3c24x0_i2c *i2c = (struct s3c24x0_i2c *)(samsung_get_base_i2c()
 142                                                         + (EXYNOS5_I2C_SPACING
 143                                                         * g_current_bus));
 144         return i2c;
 145 #else
 146         return s3c24x0_get_base_i2c();
 147 #endif
 148 }
 149
 150 static void i2c_ch_init(struct s3c24x0_i2c *i2c, int speed, int slaveadd)
 151 {
 152         ulong freq, pres = 16, div;
 153 #if (defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
 154         freq = get_i2c_clk();
 155 #else
 156         freq = get_PCLK();
 157 #endif
 158         /* calculate prescaler and divisor values */
 159         if ((freq / pres / (16 + 1)) > speed)
 160                 /* set prescaler to 512 */
 161                 pres = 512;
 162
 163         div = 0;
 164         while ((freq / pres / (div + 1)) > speed)
 165                 div++;
 166
 167         /* set prescaler, divisor according to freq, also set ACKGEN, IRQ */
 168         writel((div & 0x0F) | 0xA0 | ((pres == 512) ? 0x40 : 0), &i2c->iiccon);
 169
 170         /* init to SLAVE REVEIVE and set slaveaddr */
 171         writel(0, &i2c->iicstat);
 172         writel(slaveadd, &i2c->iicadd);
 173         /* program Master Transmit (and implicit STOP) */
 174         writel(I2C_MODE_MT | I2C_TXRX_ENA, &i2c->iicstat);
 175 }
 176
 177 /*
 178  * MULTI BUS I2C support
 179  */
 180
 181 #ifdef CONFIG_I2C_MULTI_BUS
 182 int i2c_set_bus_num(unsigned int bus)
 183 {
 184         struct s3c24x0_i2c *i2c;
 185
 186         if ((bus < 0) || (bus >= CONFIG_MAX_I2C_NUM)) {
 187                 debug("Bad bus: %d\n", bus);
 188                 return -1;
 189         }
 190
 191         g_current_bus = bus;
 192         i2c = get_base_i2c();
 193         i2c_ch_init(i2c, CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 194
 195         return 0;
 196 }
 197
 198 unsigned int i2c_get_bus_num(void)
 199 {
 200         return g_current_bus;
 201 }
 202 #endif
 203
 204 void i2c_init(int speed, int slaveadd)
 205 {
 206         struct s3c24x0_i2c *i2c;
 207 #if !(defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
 208         struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
 209 #endif
 210         int i;
 211
 212         /* By default i2c channel 0 is the current bus */
 213         g_current_bus = 0;
 214         i2c = get_base_i2c();
 215
 216         /* wait for some time to give previous transfer a chance to finish */
 217         i = I2C_TIMEOUT * 1000;
 218         while ((readl(&i2c->iicstat) & I2CSTAT_BSY) && (i > 0)) {
 219                 udelay(1000);
 220                 i--;
 221         }
 222
 223 #if !(defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5)
 224         if ((readl(&i2c->iicstat) & I2CSTAT_BSY) || GetI2CSDA() == 0) {
 225 #ifdef CONFIG_S3C2410
 226                 ulong old_gpecon = readl(&gpio->gpecon);
 227 #endif
 228 #ifdef CONFIG_S3C2400
 229                 ulong old_gpecon = readl(&gpio->pgcon);
 230 #endif
 231                 /* bus still busy probably by (most) previously interrupted
 232                    transfer */
 233
 234 #ifdef CONFIG_S3C2410
 235                 /* set I2CSDA and I2CSCL (GPE15, GPE14) to GPIO */
 236                 writel((readl(&gpio->gpecon) & ~0xF0000000) | 0x10000000,
 237                        &gpio->gpecon);
 238 #endif
 239 #ifdef CONFIG_S3C2400
 240                 /* set I2CSDA and I2CSCL (PG5, PG6) to GPIO */
 241                 writel((readl(&gpio->pgcon) & ~0x00003c00) | 0x00001000,
 242                        &gpio->pgcon);
 243 #endif
 244
 245                 /* toggle I2CSCL until bus idle */
 246                 SetI2CSCL(0);
 247                 udelay(1000);
 248                 i = 10;
 249                 while ((i > 0) && (GetI2CSDA() != 1)) {
 250                         SetI2CSCL(1);
 251                         udelay(1000);
 252                         SetI2CSCL(0);
 253                         udelay(1000);
 254                         i--;
 255                 }
 256                 SetI2CSCL(1);
 257                 udelay(1000);
 258
 259                 /* restore pin functions */
 260 #ifdef CONFIG_S3C2410
 261                 writel(old_gpecon, &gpio->gpecon);
 262 #endif
 263 #ifdef CONFIG_S3C2400
 264                 writel(old_gpecon, &gpio->pgcon);
 265 #endif
 266         }
 267 #endif /* #if !(defined CONFIG_EXYNOS4 || defined CONFIG_EXYNOS5) */
 268         i2c_ch_init(i2c, speed, slaveadd);
 269 }
 270
 271 /*
 272  * cmd_type is 0 for write, 1 for read.
 273  *
 274  * addr_len can take any value from 0-255, it is only limited
 275  * by the char, we could make it larger if needed. If it is
 276  * 0 we skip the address write cycle.
 277  */
 278 static int i2c_transfer(struct s3c24x0_i2c *i2c,
 279                         unsigned char cmd_type,
 280                         unsigned char chip,
 281                         unsigned char addr[],
 282                         unsigned char addr_len,
 283                         unsigned char data[],
 284                         unsigned short data_len)
 285 {
 286         int i, result;
 287
 288         if (data == 0 || data_len == 0) {
 289                 /*Don't support data transfer of no length or to address 0 */
 290                 debug("i2c_transfer: bad call\n");
 291                 return I2C_NOK;
 292         }
 293
 294         /* Check I2C bus idle */
 295         i = I2C_TIMEOUT * 1000;
 296         while ((readl(&i2c->iicstat) & I2CSTAT_BSY) && (i > 0)) {
 297                 udelay(1000);
 298                 i--;
 299         }
 300
 301         if (readl(&i2c->iicstat) & I2CSTAT_BSY)
 302                 return I2C_NOK_TOUT;
 303
 304         writel(readl(&i2c->iiccon) | I2CCON_ACKGEN, &i2c->iiccon);
 305         result = I2C_OK;
 306
 307         switch (cmd_type) {
 308         case I2C_WRITE:
 309                 if (addr && addr_len) {
 310                         writel(chip, &i2c->iicds);
 311                         /* send START */
 312                         writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP,
 313                                &i2c->iicstat);
 314                         i = 0;
 315                         while ((i < addr_len) && (result == I2C_OK)) {
 316                                 result = WaitForXfer(i2c);
 317                                 writel(addr[i], &i2c->iicds);
 318                                 ReadWriteByte(i2c);
 319                                 i++;
 320                         }
 321                         i = 0;
 322                         while ((i < data_len) && (result == I2C_OK)) {
 323                                 result = WaitForXfer(i2c);
 324                                 writel(data[i], &i2c->iicds);
 325                                 ReadWriteByte(i2c);
 326                                 i++;
 327                         }
 328                 } else {
 329                         writel(chip, &i2c->iicds);
 330                         /* send START */
 331                         writel(I2C_MODE_MT | I2C_TXRX_ENA | I2C_START_STOP,
 332                                &i2c->iicstat);
 333                         i = 0;
 334                         while ((i < data_len) && (result = I2C_OK)) {
 335                                 result = WaitForXfer(i2c);
 336                                 writel(data[i], &i2c->iicds);
 337                                 ReadWriteByte(i2c);
 338                                 i++;
 339                         }
 340                 }
 341
 342                 if (result == I2C_OK)
 343                         result = WaitForXfer(i2c);
 344
 345                 /* send STOP */
 346                 writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->iicstat);
 347                 ReadWriteByte(i2c);
 348                 break;
 349
 350         case I2C_READ:
 351                 if (addr && addr_len) {
 352                         writel(I2C_MODE_MT | I2C_TXRX_ENA, &i2c->iicstat);
 353                         writel(chip, &i2c->iicds);
 354                         /* send START */
 355                         writel(readl(&i2c->iicstat) | I2C_START_STOP,
 356                                &i2c->iicstat);
 357                         result = WaitForXfer(i2c);
 358                         if (IsACK(i2c)) {
 359                                 i = 0;
 360                                 while ((i < addr_len) && (result == I2C_OK)) {
 361                                         writel(addr[i], &i2c->iicds);
 362                                         ReadWriteByte(i2c);
 363                                         result = WaitForXfer(i2c);
 364                                         i++;
 365                                 }
 366
 367                                 writel(chip, &i2c->iicds);
 368                                 /* resend START */
 369                                 writel(I2C_MODE_MR | I2C_TXRX_ENA |
 370                                        I2C_START_STOP, &i2c->iicstat);
 371                         ReadWriteByte(i2c);
 372                         result = WaitForXfer(i2c);
 373                                 i = 0;
 374                                 while ((i < data_len) && (result == I2C_OK)) {
 375                                         /* disable ACK for final READ */
 376                                         if (i == data_len - 1)
 377                                                 writel(readl(&i2c->iiccon)
 378                                                         & ~I2CCON_ACKGEN,
 379                                                         &i2c->iiccon);
 380                                 ReadWriteByte(i2c);
 381                                 result = WaitForXfer(i2c);
 382                                         data[i] = readl(&i2c->iicds);
 383                                         i++;
 384                                 }
 385                         } else {
 386                                 result = I2C_NACK;
 387                         }
 388
 389                 } else {
 390                         writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->iicstat);
 391                         writel(chip, &i2c->iicds);
 392                         /* send START */
 393                         writel(readl(&i2c->iicstat) | I2C_START_STOP,
 394                                &i2c->iicstat);
 395                         result = WaitForXfer(i2c);
 396
 397                         if (IsACK(i2c)) {
 398                                 i = 0;
 399                                 while ((i < data_len) && (result == I2C_OK)) {
 400                                         /* disable ACK for final READ */
 401                                         if (i == data_len - 1)
 402                                                 writel(readl(&i2c->iiccon) &
 403                                                         ~I2CCON_ACKGEN,
 404                                                         &i2c->iiccon);
 405                                         ReadWriteByte(i2c);
 406                                         result = WaitForXfer(i2c);
 407                                         data[i] = readl(&i2c->iicds);
 408                                         i++;
 409                                 }
 410                         } else {
 411                                 result = I2C_NACK;
 412                         }
 413                 }
 414
 415                 /* send STOP */
 416                 writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->iicstat);
 417                 ReadWriteByte(i2c);
 418                 break;
 419
 420         default:
 421                 debug("i2c_transfer: bad call\n");
 422                 result = I2C_NOK;
 423                 break;
 424         }
 425
 426         return result;
 427 }
 428
 429 int i2c_probe(uchar chip)
 430 {
 431         struct s3c24x0_i2c *i2c;
 432         uchar buf[1];
 433
 434         i2c = get_base_i2c();
 435         buf[0] = 0;
 436
 437         /*
 438          * What is needed is to send the chip address and verify that the
 439          * address was <ACK>ed (i.e. there was a chip at that address which
 440          * drove the data line low).
 441          */
 442         return i2c_transfer(i2c, I2C_READ, chip << 1, 0, 0, buf, 1) != I2C_OK;
 443 }
 444
 445 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 446 {
 447         struct s3c24x0_i2c *i2c;
 448         uchar xaddr[4];
 449         int ret;
 450
 451         if (alen > 4) {
 452                 debug("I2C read: addr len %d not supported\n", alen);
 453                 return 1;
 454         }
 455
 456         if (alen > 0) {
 457                 xaddr[0] = (addr >> 24) & 0xFF;
 458                 xaddr[1] = (addr >> 16) & 0xFF;
 459                 xaddr[2] = (addr >> 8) & 0xFF;
 460                 xaddr[3] = addr & 0xFF;
 461         }
 462
 463 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
 464         /*
 465          * EEPROM chips that implement "address overflow" are ones
 466          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
 467          * address and the extra bits end up in the "chip address"
 468          * bit slots. This makes a 24WC08 (1Kbyte) chip look like
 469          * four 256 byte chips.
 470          *
 471          * Note that we consider the length of the address field to
 472          * still be one byte because the extra address bits are
 473          * hidden in the chip address.
 474          */
 475         if (alen > 0)
 476                 chip |= ((addr >> (alen * 8)) &
 477                          CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
 478 #endif
 479         i2c = get_base_i2c();
 480         ret = i2c_transfer(i2c, I2C_READ, chip << 1, &xaddr[4 - alen], alen,
 481                         buffer, len);
 482         if (ret != 0) {
 483                 debug("I2c read: failed %d\n", ret);
 484                 return 1;
 485         }
 486         return 0;
 487 }
 488
 489 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 490 {
 491         struct s3c24x0_i2c *i2c;
 492         uchar xaddr[4];
 493
 494         if (alen > 4) {
 495                 debug("I2C write: addr len %d not supported\n", alen);
 496                 return 1;
 497         }
 498
 499         if (alen > 0) {
 500                 xaddr[0] = (addr >> 24) & 0xFF;
 501                 xaddr[1] = (addr >> 16) & 0xFF;
 502                 xaddr[2] = (addr >> 8) & 0xFF;
 503                 xaddr[3] = addr & 0xFF;
 504         }
 505 #ifdef CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW
 506         /*
 507          * EEPROM chips that implement "address overflow" are ones
 508          * like Catalyst 24WC04/08/16 which has 9/10/11 bits of
 509          * address and the extra bits end up in the "chip address"
 510          * bit slots. This makes a 24WC08 (1Kbyte) chip look like
 511          * four 256 byte chips.
 512          *
 513          * Note that we consider the length of the address field to
 514          * still be one byte because the extra address bits are
 515          * hidden in the chip address.
 516          */
 517         if (alen > 0)
 518                 chip |= ((addr >> (alen * 8)) &
 519                          CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
 520 #endif
 521         i2c = get_base_i2c();
 522         return (i2c_transfer
 523                 (i2c, I2C_WRITE, chip << 1, &xaddr[4 - alen], alen, buffer,
 524                  len) != 0);
 525 }
 526
 527 #ifdef CONFIG_OF_CONTROL
 528 void board_i2c_init(const void *blob)
 529 {
 530         int node_list[CONFIG_MAX_I2C_NUM];
 531         int count, i;
 532
 533         count = fdtdec_find_aliases_for_id(blob, "i2c",
 534                 COMPAT_SAMSUNG_S3C2440_I2C, node_list,
 535                 CONFIG_MAX_I2C_NUM);
 536
 537         for (i = 0; i < count; i++) {
 538                 struct s3c24x0_i2c_bus *bus;
 539                 int node = node_list[i];
 540
 541                 if (node <= 0)
 542                         continue;
 543                 bus = &i2c_bus[i];
 544                 bus->regs = (struct s3c24x0_i2c *)
 545                         fdtdec_get_addr(blob, node, "reg");
 546                 bus->id = pinmux_decode_periph_id(blob, node);
 547                 bus->node = node;
 548                 bus->bus_num = i2c_busses++;
 549                 exynos_pinmux_config(bus->id, 0);
 550         }
 551 }
 552
 553 static struct s3c24x0_i2c_bus *get_bus(unsigned int bus_idx)
 554 {
 555         if (bus_idx < i2c_busses)
 556                 return &i2c_bus[bus_idx];
 557
 558         debug("Undefined bus: %d\n", bus_idx);
 559         return NULL;
 560 }
 561
 562 int i2c_get_bus_num_fdt(int node)
 563 {
 564         int i;
 565
 566         for (i = 0; i < i2c_busses; i++) {
 567                 if (node == i2c_bus[i].node)
 568                         return i;
 569         }
 570
 571         debug("%s: Can't find any matched I2C bus\n", __func__);
 572         return -1;
 573 }
 574
 575 int i2c_reset_port_fdt(const void *blob, int node)
 576 {
 577         struct s3c24x0_i2c_bus *i2c;
 578         int bus;
 579
 580         bus = i2c_get_bus_num_fdt(node);
 581         if (bus < 0) {
 582                 debug("could not get bus for node %d\n", node);
 583                 return -1;
 584         }
 585
 586         i2c = get_bus(bus);
 587         if (!i2c) {
 588                 debug("get_bus() failed for node node %d\n", node);
 589                 return -1;
 590         }
 591
 592         i2c_ch_init(i2c->regs, CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 593
 594         return 0;
 595 }
 596 #endif
 597
 598 #endif /* CONFIG_HARD_I2C */