drivers/i2c/designware_i2c.c

   1 /*
   2  * (C) Copyright 2009
   3  * Vipin Kumar, ST Micoelectronics, vipin.kumar@st.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 #include <asm/io.h>
  26 #include <asm/arch/hardware.h>
  27 #include "designware_i2c.h"
  28
  29 #ifdef CONFIG_I2C_MULTI_BUS
  30 static unsigned int bus_initialized[CONFIG_SYS_I2C_BUS_MAX];
  31 static unsigned int current_bus = 0;
  32 #endif
  33
  34 static struct i2c_regs *i2c_regs_p =
  35     (struct i2c_regs *)CONFIG_SYS_I2C_BASE;
  36
  37 /*
  38  * set_speed - Set the i2c speed mode (standard, high, fast)
  39  * @i2c_spd:    required i2c speed mode
  40  *
  41  * Set the i2c speed mode (standard, high, fast)
  42  */
  43 static void set_speed(int i2c_spd)
  44 {
  45         unsigned int cntl;
  46         unsigned int hcnt, lcnt;
  47         unsigned int high, low;
  48         unsigned int enbl;
  49
  50         /* to set speed cltr must be disabled */
  51         enbl = readl(&i2c_regs_p->ic_enable);
  52         enbl &= ~IC_ENABLE_0B;
  53         writel(enbl, &i2c_regs_p->ic_enable);
  54
  55
  56         cntl = (readl(&i2c_regs_p->ic_con) & (~IC_CON_SPD_MSK));
  57
  58         switch (i2c_spd) {
  59         case IC_SPEED_MODE_MAX:
  60                 cntl |= IC_CON_SPD_HS;
  61                 high = MIN_HS_SCL_HIGHTIME;
  62                 low = MIN_HS_SCL_LOWTIME;
  63                 break;
  64
  65         case IC_SPEED_MODE_STANDARD:
  66                 cntl |= IC_CON_SPD_SS;
  67                 high = MIN_SS_SCL_HIGHTIME;
  68                 low = MIN_SS_SCL_LOWTIME;
  69                 break;
  70
  71         case IC_SPEED_MODE_FAST:
  72         default:
  73                 cntl |= IC_CON_SPD_FS;
  74                 high = MIN_FS_SCL_HIGHTIME;
  75                 low = MIN_FS_SCL_LOWTIME;
  76                 break;
  77         }
  78
  79         writel(cntl, &i2c_regs_p->ic_con);
  80
  81         hcnt = (IC_CLK * high) / NANO_TO_MICRO;
  82         writel(hcnt, &i2c_regs_p->ic_fs_scl_hcnt);
  83
  84         lcnt = (IC_CLK * low) / NANO_TO_MICRO;
  85         writel(lcnt, &i2c_regs_p->ic_fs_scl_lcnt);
  86
  87         /* re-enable i2c ctrl back now that speed is set */
  88         enbl |= IC_ENABLE_0B;
  89         writel(enbl, &i2c_regs_p->ic_enable);
  90 }
  91
  92 /*
  93  * i2c_set_bus_speed - Set the i2c speed
  94  * @speed:      required i2c speed
  95  *
  96  * Set the i2c speed.
  97  */
  98 int i2c_set_bus_speed(int speed)
  99 {
 100         if (speed >= I2C_MAX_SPEED)
 101                 set_speed(IC_SPEED_MODE_MAX);
 102         else if (speed >= I2C_FAST_SPEED)
 103                 set_speed(IC_SPEED_MODE_FAST);
 104         else
 105                 set_speed(IC_SPEED_MODE_STANDARD);
 106
 107         return 0;
 108 }
 109
 110 /*
 111  * i2c_get_bus_speed - Gets the i2c speed
 112  *
 113  * Gets the i2c speed.
 114  */
 115 int i2c_get_bus_speed(void)
 116 {
 117         u32 cntl;
 118
 119         cntl = (readl(&i2c_regs_p->ic_con) & IC_CON_SPD_MSK);
 120
 121         if (cntl == IC_CON_SPD_HS)
 122                 return I2C_MAX_SPEED;
 123         else if (cntl == IC_CON_SPD_FS)
 124                 return I2C_FAST_SPEED;
 125         else if (cntl == IC_CON_SPD_SS)
 126                 return I2C_STANDARD_SPEED;
 127
 128         return 0;
 129 }
 130
 131 /*
 132  * i2c_init - Init function
 133  * @speed:      required i2c speed
 134  * @slaveadd:   slave address for the device
 135  *
 136  * Initialization function.
 137  */
 138 void i2c_init(int speed, int slaveadd)
 139 {
 140         unsigned int enbl;
 141
 142         /* Disable i2c */
 143         enbl = readl(&i2c_regs_p->ic_enable);
 144         enbl &= ~IC_ENABLE_0B;
 145         writel(enbl, &i2c_regs_p->ic_enable);
 146
 147         writel((IC_CON_SD | IC_CON_SPD_FS | IC_CON_MM), &i2c_regs_p->ic_con);
 148         writel(IC_RX_TL, &i2c_regs_p->ic_rx_tl);
 149         writel(IC_TX_TL, &i2c_regs_p->ic_tx_tl);
 150         i2c_set_bus_speed(speed);
 151         writel(IC_STOP_DET, &i2c_regs_p->ic_intr_mask);
 152         writel(slaveadd, &i2c_regs_p->ic_sar);
 153
 154         /* Enable i2c */
 155         enbl = readl(&i2c_regs_p->ic_enable);
 156         enbl |= IC_ENABLE_0B;
 157         writel(enbl, &i2c_regs_p->ic_enable);
 158
 159 #ifdef CONFIG_I2C_MULTI_BUS
 160         bus_initialized[current_bus] = 1;
 161 #endif
 162 }
 163
 164 /*
 165  * i2c_setaddress - Sets the target slave address
 166  * @i2c_addr:   target i2c address
 167  *
 168  * Sets the target slave address.
 169  */
 170 static void i2c_setaddress(unsigned int i2c_addr)
 171 {
 172         writel(i2c_addr, &i2c_regs_p->ic_tar);
 173 }
 174
 175 /*
 176  * i2c_flush_rxfifo - Flushes the i2c RX FIFO
 177  *
 178  * Flushes the i2c RX FIFO
 179  */
 180 static void i2c_flush_rxfifo(void)
 181 {
 182         while (readl(&i2c_regs_p->ic_status) & IC_STATUS_RFNE)
 183                 readl(&i2c_regs_p->ic_cmd_data);
 184 }
 185
 186 /*
 187  * i2c_wait_for_bb - Waits for bus busy
 188  *
 189  * Waits for bus busy
 190  */
 191 static int i2c_wait_for_bb(void)
 192 {
 193         unsigned long start_time_bb = get_timer(0);
 194
 195         while ((readl(&i2c_regs_p->ic_status) & IC_STATUS_MA) ||
 196                !(readl(&i2c_regs_p->ic_status) & IC_STATUS_TFE)) {
 197
 198                 /* Evaluate timeout */
 199                 if (get_timer(start_time_bb) > (unsigned long)(I2C_BYTE_TO_BB))
 200                         return 1;
 201         }
 202
 203         return 0;
 204 }
 205
 206 /* check parameters for i2c_read and i2c_write */
 207 static int check_params(uint addr, int alen, uchar *buffer, int len)
 208 {
 209         if (buffer == NULL) {
 210                 printf("Buffer is invalid\n");
 211                 return 1;
 212         }
 213
 214         if (alen > 1) {
 215                 printf("addr len %d not supported\n", alen);
 216                 return 1;
 217         }
 218
 219         if (addr + len > 256) {
 220                 printf("address out of range\n");
 221                 return 1;
 222         }
 223
 224         return 0;
 225 }
 226
 227 static int i2c_xfer_init(uchar chip, uint addr)
 228 {
 229         if (i2c_wait_for_bb())
 230                 return 1;
 231
 232         i2c_setaddress(chip);
 233         writel(addr, &i2c_regs_p->ic_cmd_data);
 234
 235         return 0;
 236 }
 237
 238 static int i2c_xfer_finish(void)
 239 {
 240         ulong start_stop_det = get_timer(0);
 241
 242         while (1) {
 243                 if ((readl(&i2c_regs_p->ic_raw_intr_stat) & IC_STOP_DET)) {
 244                         readl(&i2c_regs_p->ic_clr_stop_det);
 245                         break;
 246                 } else if (get_timer(start_stop_det) > I2C_STOPDET_TO) {
 247                         break;
 248                 }
 249         }
 250
 251         if (i2c_wait_for_bb()) {
 252                 printf("Timed out waiting for bus\n");
 253                 return 1;
 254         }
 255
 256         i2c_flush_rxfifo();
 257
 258         /* Wait for read/write operation to complete on actual memory */
 259         udelay(10000);
 260
 261         return 0;
 262 }
 263
 264 /*
 265  * i2c_read - Read from i2c memory
 266  * @chip:       target i2c address
 267  * @addr:       address to read from
 268  * @alen:
 269  * @buffer:     buffer for read data
 270  * @len:        no of bytes to be read
 271  *
 272  * Read from i2c memory.
 273  */
 274 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 275 {
 276         unsigned long start_time_rx;
 277
 278         if (check_params(addr, alen, buffer, len))
 279                 return 1;
 280
 281         if (i2c_xfer_init(chip, addr))
 282                 return 1;
 283
 284         start_time_rx = get_timer(0);
 285         while (len) {
 286                 writel(IC_CMD, &i2c_regs_p->ic_cmd_data);
 287
 288                 if (readl(&i2c_regs_p->ic_status) & IC_STATUS_RFNE) {
 289                         *buffer++ = (uchar)readl(&i2c_regs_p->ic_cmd_data);
 290                         len--;
 291                         start_time_rx = get_timer(0);
 292
 293                 } else if (get_timer(start_time_rx) > I2C_BYTE_TO) {
 294                                 return 1;
 295                 }
 296         }
 297
 298         return i2c_xfer_finish();
 299 }
 300
 301 /*
 302  * i2c_write - Write to i2c memory
 303  * @chip:       target i2c address
 304  * @addr:       address to read from
 305  * @alen:
 306  * @buffer:     buffer for read data
 307  * @len:        no of bytes to be read
 308  *
 309  * Write to i2c memory.
 310  */
 311 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 312 {
 313         int nb = len;
 314         unsigned long start_time_tx;
 315
 316         if (check_params(addr, alen, buffer, len))
 317                 return 1;
 318
 319         if (i2c_xfer_init(chip, addr))
 320                 return 1;
 321
 322         start_time_tx = get_timer(0);
 323         while (len) {
 324                 if (readl(&i2c_regs_p->ic_status) & IC_STATUS_TFNF) {
 325                         writel(*buffer, &i2c_regs_p->ic_cmd_data);
 326                         buffer++;
 327                         len--;
 328                         start_time_tx = get_timer(0);
 329
 330                 } else if (get_timer(start_time_tx) > (nb * I2C_BYTE_TO)) {
 331                                 printf("Timed out. i2c write Failed\n");
 332                                 return 1;
 333                 }
 334         }
 335
 336         return i2c_xfer_finish();
 337 }
 338
 339 /*
 340  * i2c_probe - Probe the i2c chip
 341  */
 342 int i2c_probe(uchar chip)
 343 {
 344         u32 tmp;
 345         int ret;
 346
 347         /*
 348          * Try to read the first location of the chip.
 349          */
 350         ret = i2c_read(chip, 0, 1, (uchar *)&tmp, 1);
 351         if (ret)
 352                 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 353
 354         return ret;
 355 }
 356
 357 #ifdef CONFIG_I2C_MULTI_BUS
 358 int i2c_set_bus_num(unsigned int bus)
 359 {
 360         switch (bus) {
 361         case 0:
 362                 i2c_regs_p = (void *)CONFIG_SYS_I2C_BASE;
 363                 break;
 364 #ifdef CONFIG_SYS_I2C_BASE1
 365         case 1:
 366                 i2c_regs_p = (void *)CONFIG_SYS_I2C_BASE1;
 367                 break;
 368 #endif
 369 #ifdef CONFIG_SYS_I2C_BASE2
 370         case 2:
 371                 i2c_regs_p = (void *)CONFIG_SYS_I2C_BASE2;
 372                 break;
 373 #endif
 374 #ifdef CONFIG_SYS_I2C_BASE3
 375         case 3:
 376                 i2c_regs_p = (void *)CONFIG_SYS_I2C_BASE3;
 377                 break;
 378 #endif
 379 #ifdef CONFIG_SYS_I2C_BASE4
 380         case 4:
 381                 i2c_regs_p = (void *)CONFIG_SYS_I2C_BASE4;
 382                 break;
 383 #endif
 384 #ifdef CONFIG_SYS_I2C_BASE5
 385         case 5:
 386                 i2c_regs_p = (void *)CONFIG_SYS_I2C_BASE5;
 387                 break;
 388 #endif
 389 #ifdef CONFIG_SYS_I2C_BASE6
 390         case 6:
 391                 i2c_regs_p = (void *)CONFIG_SYS_I2C_BASE6;
 392                 break;
 393 #endif
 394 #ifdef CONFIG_SYS_I2C_BASE7
 395         case 7:
 396                 i2c_regs_p = (void *)CONFIG_SYS_I2C_BASE7;
 397                 break;
 398 #endif
 399 #ifdef CONFIG_SYS_I2C_BASE8
 400         case 8:
 401                 i2c_regs_p = (void *)CONFIG_SYS_I2C_BASE8;
 402                 break;
 403 #endif
 404 #ifdef CONFIG_SYS_I2C_BASE9
 405         case 9:
 406                 i2c_regs_p = (void *)CONFIG_SYS_I2C_BASE9;
 407                 break;
 408 #endif
 409         default:
 410                 printf("Bad bus: %d\n", bus);
 411                 return -1;
 412         }
 413
 414         current_bus = bus;
 415
 416         if (!bus_initialized[current_bus])
 417                 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 418
 419         return 0;
 420 }
 421
 422 int i2c_get_bus_num(void)
 423 {
 424         return current_bus;
 425 }
 426 #endif