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 static struct i2c_regs *const i2c_regs_p =
  30     (struct i2c_regs *)CONFIG_SYS_I2C_BASE;
  31
  32 /*
  33  * set_speed - Set the i2c speed mode (standard, high, fast)
  34  * @i2c_spd:    required i2c speed mode
  35  *
  36  * Set the i2c speed mode (standard, high, fast)
  37  */
  38 static void set_speed(int i2c_spd)
  39 {
  40         unsigned int cntl;
  41         unsigned int hcnt, lcnt;
  42         unsigned int high, low;
  43         unsigned int enbl;
  44
  45         /* to set speed cltr must be disabled */
  46         enbl = readl(&i2c_regs_p->ic_enable);
  47         enbl &= ~IC_ENABLE_0B;
  48         writel(enbl, &i2c_regs_p->ic_enable);
  49
  50
  51         cntl = (readl(&i2c_regs_p->ic_con) & (~IC_CON_SPD_MSK));
  52
  53         switch (i2c_spd) {
  54         case IC_SPEED_MODE_MAX:
  55                 cntl |= IC_CON_SPD_HS;
  56                 high = MIN_HS_SCL_HIGHTIME;
  57                 low = MIN_HS_SCL_LOWTIME;
  58                 break;
  59
  60         case IC_SPEED_MODE_STANDARD:
  61                 cntl |= IC_CON_SPD_SS;
  62                 high = MIN_SS_SCL_HIGHTIME;
  63                 low = MIN_SS_SCL_LOWTIME;
  64                 break;
  65
  66         case IC_SPEED_MODE_FAST:
  67         default:
  68                 cntl |= IC_CON_SPD_FS;
  69                 high = MIN_FS_SCL_HIGHTIME;
  70                 low = MIN_FS_SCL_LOWTIME;
  71                 break;
  72         }
  73
  74         writel(cntl, &i2c_regs_p->ic_con);
  75
  76         hcnt = (IC_CLK * high) / NANO_TO_MICRO;
  77         writel(hcnt, &i2c_regs_p->ic_fs_scl_hcnt);
  78
  79         lcnt = (IC_CLK * low) / NANO_TO_MICRO;
  80         writel(lcnt, &i2c_regs_p->ic_fs_scl_lcnt);
  81
  82         /* re-enable i2c ctrl back now that speed is set */
  83         enbl |= IC_ENABLE_0B;
  84         writel(enbl, &i2c_regs_p->ic_enable);
  85 }
  86
  87 /*
  88  * i2c_set_bus_speed - Set the i2c speed
  89  * @speed:      required i2c speed
  90  *
  91  * Set the i2c speed.
  92  */
  93 int i2c_set_bus_speed(int speed)
  94 {
  95         if (speed >= I2C_MAX_SPEED)
  96                 set_speed(IC_SPEED_MODE_MAX);
  97         else if (speed >= I2C_FAST_SPEED)
  98                 set_speed(IC_SPEED_MODE_FAST);
  99         else
 100                 set_speed(IC_SPEED_MODE_STANDARD);
 101
 102         return 0;
 103 }
 104
 105 /*
 106  * i2c_get_bus_speed - Gets the i2c speed
 107  *
 108  * Gets the i2c speed.
 109  */
 110 int i2c_get_bus_speed(void)
 111 {
 112         u32 cntl;
 113
 114         cntl = (readl(&i2c_regs_p->ic_con) & IC_CON_SPD_MSK);
 115
 116         if (cntl == IC_CON_SPD_HS)
 117                 return I2C_MAX_SPEED;
 118         else if (cntl == IC_CON_SPD_FS)
 119                 return I2C_FAST_SPEED;
 120         else if (cntl == IC_CON_SPD_SS)
 121                 return I2C_STANDARD_SPEED;
 122
 123         return 0;
 124 }
 125
 126 /*
 127  * i2c_init - Init function
 128  * @speed:      required i2c speed
 129  * @slaveadd:   slave address for the device
 130  *
 131  * Initialization function.
 132  */
 133 void i2c_init(int speed, int slaveadd)
 134 {
 135         unsigned int enbl;
 136
 137         /* Disable i2c */
 138         enbl = readl(&i2c_regs_p->ic_enable);
 139         enbl &= ~IC_ENABLE_0B;
 140         writel(enbl, &i2c_regs_p->ic_enable);
 141
 142         writel((IC_CON_SD | IC_CON_SPD_FS | IC_CON_MM), &i2c_regs_p->ic_con);
 143         writel(IC_RX_TL, &i2c_regs_p->ic_rx_tl);
 144         writel(IC_TX_TL, &i2c_regs_p->ic_tx_tl);
 145         i2c_set_bus_speed(speed);
 146         writel(IC_STOP_DET, &i2c_regs_p->ic_intr_mask);
 147         writel(slaveadd, &i2c_regs_p->ic_sar);
 148
 149         /* Enable i2c */
 150         enbl = readl(&i2c_regs_p->ic_enable);
 151         enbl |= IC_ENABLE_0B;
 152         writel(enbl, &i2c_regs_p->ic_enable);
 153 }
 154
 155 /*
 156  * i2c_setaddress - Sets the target slave address
 157  * @i2c_addr:   target i2c address
 158  *
 159  * Sets the target slave address.
 160  */
 161 static void i2c_setaddress(unsigned int i2c_addr)
 162 {
 163         writel(i2c_addr, &i2c_regs_p->ic_tar);
 164 }
 165
 166 /*
 167  * i2c_flush_rxfifo - Flushes the i2c RX FIFO
 168  *
 169  * Flushes the i2c RX FIFO
 170  */
 171 static void i2c_flush_rxfifo(void)
 172 {
 173         while (readl(&i2c_regs_p->ic_status) & IC_STATUS_RFNE)
 174                 readl(&i2c_regs_p->ic_cmd_data);
 175 }
 176
 177 /*
 178  * i2c_wait_for_bb - Waits for bus busy
 179  *
 180  * Waits for bus busy
 181  */
 182 static int i2c_wait_for_bb(void)
 183 {
 184         unsigned long start_time_bb = get_timer(0);
 185
 186         while ((readl(&i2c_regs_p->ic_status) & IC_STATUS_MA) ||
 187                !(readl(&i2c_regs_p->ic_status) & IC_STATUS_TFE)) {
 188
 189                 /* Evaluate timeout */
 190                 if (get_timer(start_time_bb) > (unsigned long)(I2C_BYTE_TO_BB))
 191                         return 1;
 192         }
 193
 194         return 0;
 195 }
 196
 197 /* check parameters for i2c_read and i2c_write */
 198 static int check_params(uint addr, int alen, uchar *buffer, int len)
 199 {
 200         if (buffer == NULL) {
 201                 printf("Buffer is invalid\n");
 202                 return 1;
 203         }
 204
 205         if (alen > 1) {
 206                 printf("addr len %d not supported\n", alen);
 207                 return 1;
 208         }
 209
 210         if (addr + len > 256) {
 211                 printf("address out of range\n");
 212                 return 1;
 213         }
 214
 215         return 0;
 216 }
 217
 218 static int i2c_xfer_init(uchar chip, uint addr)
 219 {
 220         if (i2c_wait_for_bb())
 221                 return 1;
 222
 223         i2c_setaddress(chip);
 224         writel(addr, &i2c_regs_p->ic_cmd_data);
 225
 226         return 0;
 227 }
 228
 229 static int i2c_xfer_finish(void)
 230 {
 231         ulong start_stop_det = get_timer(0);
 232
 233         while (1) {
 234                 if ((readl(&i2c_regs_p->ic_raw_intr_stat) & IC_STOP_DET)) {
 235                         readl(&i2c_regs_p->ic_clr_stop_det);
 236                         break;
 237                 } else if (get_timer(start_stop_det) > I2C_STOPDET_TO) {
 238                         break;
 239                 }
 240         }
 241
 242         if (i2c_wait_for_bb()) {
 243                 printf("Timed out waiting for bus\n");
 244                 return 1;
 245         }
 246
 247         i2c_flush_rxfifo();
 248
 249         /* Wait for read/write operation to complete on actual memory */
 250         udelay(10000);
 251
 252         return 0;
 253 }
 254
 255 /*
 256  * i2c_read - Read from i2c memory
 257  * @chip:       target i2c address
 258  * @addr:       address to read from
 259  * @alen:
 260  * @buffer:     buffer for read data
 261  * @len:        no of bytes to be read
 262  *
 263  * Read from i2c memory.
 264  */
 265 int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
 266 {
 267         unsigned long start_time_rx;
 268
 269         if (check_params(addr, alen, buffer, len))
 270                 return 1;
 271
 272         if (i2c_xfer_init(chip, addr))
 273                 return 1;
 274
 275         start_time_rx = get_timer(0);
 276         while (len) {
 277                 writel(IC_CMD, &i2c_regs_p->ic_cmd_data);
 278
 279                 if (readl(&i2c_regs_p->ic_status) & IC_STATUS_RFNE) {
 280                         *buffer++ = (uchar)readl(&i2c_regs_p->ic_cmd_data);
 281                         len--;
 282                         start_time_rx = get_timer(0);
 283
 284                 } else if (get_timer(start_time_rx) > I2C_BYTE_TO) {
 285                                 return 1;
 286                 }
 287         }
 288
 289         return i2c_xfer_finish();
 290 }
 291
 292 /*
 293  * i2c_write - Write to i2c memory
 294  * @chip:       target i2c address
 295  * @addr:       address to read from
 296  * @alen:
 297  * @buffer:     buffer for read data
 298  * @len:        no of bytes to be read
 299  *
 300  * Write to i2c memory.
 301  */
 302 int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
 303 {
 304         int nb = len;
 305         unsigned long start_time_tx;
 306
 307         if (check_params(addr, alen, buffer, len))
 308                 return 1;
 309
 310         if (i2c_xfer_init(chip, addr))
 311                 return 1;
 312
 313         start_time_tx = get_timer(0);
 314         while (len) {
 315                 if (readl(&i2c_regs_p->ic_status) & IC_STATUS_TFNF) {
 316                         writel(*buffer, &i2c_regs_p->ic_cmd_data);
 317                         buffer++;
 318                         len--;
 319                         start_time_tx = get_timer(0);
 320
 321                 } else if (get_timer(start_time_tx) > (nb * I2C_BYTE_TO)) {
 322                                 printf("Timed out. i2c write Failed\n");
 323                                 return 1;
 324                 }
 325         }
 326
 327         return i2c_xfer_finish();
 328 }
 329
 330 /*
 331  * i2c_probe - Probe the i2c chip
 332  */
 333 int i2c_probe(uchar chip)
 334 {
 335         u32 tmp;
 336         int ret;
 337
 338         /*
 339          * Try to read the first location of the chip.
 340          */
 341         ret = i2c_read(chip, 0, 1, (uchar *)&tmp, 1);
 342         if (ret)
 343                 i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
 344
 345         return ret;
 346 }