drivers/i2c/davinci_i2c.c

   1 /*
   2  * TI DaVinci (TMS320DM644x) I2C driver.
   3  *
   4  * Copyright (C) 2007 Sergey Kubushyn <ksi@koi8.net>
   5  *
   6  * --------------------------------------------------------
   7  *
   8  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11 #include <common.h>
  12 #include <i2c.h>
  13 #include <asm/arch/hardware.h>
  14 #include <asm/arch/i2c_defs.h>
  15
  16 #define CHECK_NACK() \
  17         do {\
  18                 if (tmp & (I2C_TIMEOUT | I2C_STAT_NACK)) {\
  19                         REG(I2C_CON) = 0;\
  20                         return(1);\
  21                 }\
  22         } while (0)
  23
  24
  25 static int wait_for_bus(void)
  26 {
  27         int     stat, timeout;
  28
  29         REG(I2C_STAT) = 0xffff;
  30
  31         for (timeout = 0; timeout < 10; timeout++) {
  32                 if (!((stat = REG(I2C_STAT)) & I2C_STAT_BB)) {
  33                         REG(I2C_STAT) = 0xffff;
  34                         return(0);
  35                 }
  36
  37                 REG(I2C_STAT) = stat;
  38                 udelay(50000);
  39         }
  40
  41         REG(I2C_STAT) = 0xffff;
  42         return(1);
  43 }
  44
  45
  46 static int poll_i2c_irq(int mask)
  47 {
  48         int     stat, timeout;
  49
  50         for (timeout = 0; timeout < 10; timeout++) {
  51                 udelay(1000);
  52                 stat = REG(I2C_STAT);
  53                 if (stat & mask) {
  54                         return(stat);
  55                 }
  56         }
  57
  58         REG(I2C_STAT) = 0xffff;
  59         return(stat | I2C_TIMEOUT);
  60 }
  61
  62
  63 void flush_rx(void)
  64 {
  65         while (1) {
  66                 if (!(REG(I2C_STAT) & I2C_STAT_RRDY))
  67                         break;
  68
  69                 REG(I2C_DRR);
  70                 REG(I2C_STAT) = I2C_STAT_RRDY;
  71                 udelay(1000);
  72         }
  73 }
  74
  75
  76 void i2c_init(int speed, int slaveadd)
  77 {
  78         u_int32_t       div, psc;
  79
  80         if (REG(I2C_CON) & I2C_CON_EN) {
  81                 REG(I2C_CON) = 0;
  82                 udelay (50000);
  83         }
  84
  85         psc = 2;
  86         div = (CONFIG_SYS_HZ_CLOCK / ((psc + 1) * speed)) - 10; /* SCLL + SCLH */
  87         REG(I2C_PSC) = psc;                     /* 27MHz / (2 + 1) = 9MHz */
  88         REG(I2C_SCLL) = (div * 50) / 100;       /* 50% Duty */
  89         REG(I2C_SCLH) = div - REG(I2C_SCLL);
  90
  91         REG(I2C_OA) = slaveadd;
  92         REG(I2C_CNT) = 0;
  93
  94         /* Interrupts must be enabled or I2C module won't work */
  95         REG(I2C_IE) = I2C_IE_SCD_IE | I2C_IE_XRDY_IE |
  96                 I2C_IE_RRDY_IE | I2C_IE_ARDY_IE | I2C_IE_NACK_IE;
  97
  98         /* Now enable I2C controller (get it out of reset) */
  99         REG(I2C_CON) = I2C_CON_EN;
 100
 101         udelay(1000);
 102 }
 103
 104 int i2c_set_bus_speed(unsigned int speed)
 105 {
 106         i2c_init(speed, CONFIG_SYS_I2C_SLAVE);
 107         return 0;
 108 }
 109
 110 int i2c_probe(u_int8_t chip)
 111 {
 112         int     rc = 1;
 113
 114         if (chip == REG(I2C_OA)) {
 115                 return(rc);
 116         }
 117
 118         REG(I2C_CON) = 0;
 119         if (wait_for_bus()) {return(1);}
 120
 121         /* try to read one byte from current (or only) address */
 122         REG(I2C_CNT) = 1;
 123         REG(I2C_SA) = chip;
 124         REG(I2C_CON) = (I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP);
 125         udelay (50000);
 126
 127         if (!(REG(I2C_STAT) & I2C_STAT_NACK)) {
 128                 rc = 0;
 129                 flush_rx();
 130                 REG(I2C_STAT) = 0xffff;
 131         } else {
 132                 REG(I2C_STAT) = 0xffff;
 133                 REG(I2C_CON) |= I2C_CON_STP;
 134                 udelay(20000);
 135                 if (wait_for_bus()) {return(1);}
 136         }
 137
 138         flush_rx();
 139         REG(I2C_STAT) = 0xffff;
 140         REG(I2C_CNT) = 0;
 141         return(rc);
 142 }
 143
 144
 145 int i2c_read(u_int8_t chip, u_int32_t addr, int alen, u_int8_t *buf, int len)
 146 {
 147         u_int32_t       tmp;
 148         int             i;
 149
 150         if ((alen < 0) || (alen > 2)) {
 151                 printf("%s(): bogus address length %x\n", __FUNCTION__, alen);
 152                 return(1);
 153         }
 154
 155         if (wait_for_bus()) {return(1);}
 156
 157         if (alen != 0) {
 158                 /* Start address phase */
 159                 tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX;
 160                 REG(I2C_CNT) = alen;
 161                 REG(I2C_SA) = chip;
 162                 REG(I2C_CON) = tmp;
 163
 164                 tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK);
 165
 166                 CHECK_NACK();
 167
 168                 switch (alen) {
 169                         case 2:
 170                                 /* Send address MSByte */
 171                                 if (tmp & I2C_STAT_XRDY) {
 172                                         REG(I2C_DXR) = (addr >> 8) & 0xff;
 173                                 } else {
 174                                         REG(I2C_CON) = 0;
 175                                         return(1);
 176                                 }
 177
 178                                 tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK);
 179
 180                                 CHECK_NACK();
 181                                 /* No break, fall through */
 182                         case 1:
 183                                 /* Send address LSByte */
 184                                 if (tmp & I2C_STAT_XRDY) {
 185                                         REG(I2C_DXR) = addr & 0xff;
 186                                 } else {
 187                                         REG(I2C_CON) = 0;
 188                                         return(1);
 189                                 }
 190
 191                                 tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK | I2C_STAT_ARDY);
 192
 193                                 CHECK_NACK();
 194
 195                                 if (!(tmp & I2C_STAT_ARDY)) {
 196                                         REG(I2C_CON) = 0;
 197                                         return(1);
 198                                 }
 199                 }
 200         }
 201
 202         /* Address phase is over, now read 'len' bytes and stop */
 203         tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_STP;
 204         REG(I2C_CNT) = len & 0xffff;
 205         REG(I2C_SA) = chip;
 206         REG(I2C_CON) = tmp;
 207
 208         for (i = 0; i < len; i++) {
 209                 tmp = poll_i2c_irq(I2C_STAT_RRDY | I2C_STAT_NACK | I2C_STAT_ROVR);
 210
 211                 CHECK_NACK();
 212
 213                 if (tmp & I2C_STAT_RRDY) {
 214                         buf[i] = REG(I2C_DRR);
 215                 } else {
 216                         REG(I2C_CON) = 0;
 217                         return(1);
 218                 }
 219         }
 220
 221         tmp = poll_i2c_irq(I2C_STAT_SCD | I2C_STAT_NACK);
 222
 223         CHECK_NACK();
 224
 225         if (!(tmp & I2C_STAT_SCD)) {
 226                 REG(I2C_CON) = 0;
 227                 return(1);
 228         }
 229
 230         flush_rx();
 231         REG(I2C_STAT) = 0xffff;
 232         REG(I2C_CNT) = 0;
 233         REG(I2C_CON) = 0;
 234
 235         return(0);
 236 }
 237
 238
 239 int i2c_write(u_int8_t chip, u_int32_t addr, int alen, u_int8_t *buf, int len)
 240 {
 241         u_int32_t       tmp;
 242         int             i;
 243
 244         if ((alen < 0) || (alen > 2)) {
 245                 printf("%s(): bogus address length %x\n", __FUNCTION__, alen);
 246                 return(1);
 247         }
 248         if (len < 0) {
 249                 printf("%s(): bogus length %x\n", __FUNCTION__, len);
 250                 return(1);
 251         }
 252
 253         if (wait_for_bus()) {return(1);}
 254
 255         /* Start address phase */
 256         tmp = I2C_CON_EN | I2C_CON_MST | I2C_CON_STT | I2C_CON_TRX | I2C_CON_STP;
 257         REG(I2C_CNT) = (alen == 0) ? len & 0xffff : (len & 0xffff) + alen;
 258         REG(I2C_SA) = chip;
 259         REG(I2C_CON) = tmp;
 260
 261         switch (alen) {
 262                 case 2:
 263                         /* Send address MSByte */
 264                         tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK);
 265
 266                         CHECK_NACK();
 267
 268                         if (tmp & I2C_STAT_XRDY) {
 269                                 REG(I2C_DXR) = (addr >> 8) & 0xff;
 270                         } else {
 271                                 REG(I2C_CON) = 0;
 272                                 return(1);
 273                         }
 274                         /* No break, fall through */
 275                 case 1:
 276                         /* Send address LSByte */
 277                         tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK);
 278
 279                         CHECK_NACK();
 280
 281                         if (tmp & I2C_STAT_XRDY) {
 282                                 REG(I2C_DXR) = addr & 0xff;
 283                         } else {
 284                                 REG(I2C_CON) = 0;
 285                                 return(1);
 286                         }
 287         }
 288
 289         for (i = 0; i < len; i++) {
 290                 tmp = poll_i2c_irq(I2C_STAT_XRDY | I2C_STAT_NACK);
 291
 292                 CHECK_NACK();
 293
 294                 if (tmp & I2C_STAT_XRDY) {
 295                         REG(I2C_DXR) = buf[i];
 296                 } else {
 297                         return(1);
 298                 }
 299         }
 300
 301         tmp = poll_i2c_irq(I2C_STAT_SCD | I2C_STAT_NACK);
 302
 303         CHECK_NACK();
 304
 305         if (!(tmp & I2C_STAT_SCD)) {
 306                 REG(I2C_CON) = 0;
 307                 return(1);
 308         }
 309
 310         flush_rx();
 311         REG(I2C_STAT) = 0xffff;
 312         REG(I2C_CNT) = 0;
 313         REG(I2C_CON) = 0;
 314
 315         return(0);
 316 }