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