drivers/fsl_i2c.c

   1 /*
   2  * Copyright 2006 Freescale Semiconductor, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * Version 2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  16  * MA 02111-1307 USA
  17  */
  18
  19 #include <common.h>
  20
  21 #ifdef CONFIG_FSL_I2C
  22 #ifdef CONFIG_HARD_I2C
  23
  24 #include <command.h>
  25 #include <i2c.h>                /* Functional interface */
  26
  27 #include <asm/io.h>
  28 #include <asm/fsl_i2c.h>        /* HW definitions */
  29
  30 #define I2C_TIMEOUT     (CFG_HZ / 4)
  31 #define I2C             ((struct fsl_i2c *)(CFG_IMMR + CFG_I2C_OFFSET))
  32
  33
  34 void
  35 i2c_init(int speed, int slaveadd)
  36 {
  37         /* stop I2C controller */
  38         writeb(0x0, &I2C->cr);
  39
  40         /* set clock */
  41         writeb(0x3f, &I2C->fdr);
  42
  43         /* set default filter */
  44         writeb(0x10, &I2C->dfsrr);
  45
  46         /* write slave address */
  47         writeb(slaveadd, &I2C->adr);
  48
  49         /* clear status register */
  50         writeb(0x0, &I2C->sr);
  51
  52         /* start I2C controller */
  53         writeb(I2C_CR_MEN, &I2C->cr);
  54 }
  55
  56 static __inline__ int
  57 i2c_wait4bus(void)
  58 {
  59         ulong timeval = get_timer(0);
  60
  61         while (readb(&I2C->sr) & I2C_SR_MBB) {
  62                 if (get_timer(timeval) > I2C_TIMEOUT) {
  63                         return -1;
  64                 }
  65         }
  66
  67         return 0;
  68 }
  69
  70 static __inline__ int
  71 i2c_wait(int write)
  72 {
  73         u32 csr;
  74         ulong timeval = get_timer(0);
  75
  76         do {
  77                 csr = readb(&I2C->sr);
  78                 if (!(csr & I2C_SR_MIF))
  79                         continue;
  80
  81                 writeb(0x0, &I2C->sr);
  82
  83                 if (csr & I2C_SR_MAL) {
  84                         debug("i2c_wait: MAL\n");
  85                         return -1;
  86                 }
  87
  88                 if (!(csr & I2C_SR_MCF))        {
  89                         debug("i2c_wait: unfinished\n");
  90                         return -1;
  91                 }
  92
  93                 if (write == I2C_WRITE && (csr & I2C_SR_RXAK)) {
  94                         debug("i2c_wait: No RXACK\n");
  95                         return -1;
  96                 }
  97
  98                 return 0;
  99         } while (get_timer (timeval) < I2C_TIMEOUT);
 100
 101         debug("i2c_wait: timed out\n");
 102         return -1;
 103 }
 104
 105 static __inline__ int
 106 i2c_write_addr (u8 dev, u8 dir, int rsta)
 107 {
 108         writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX
 109                | (rsta ? I2C_CR_RSTA : 0),
 110                &I2C->cr);
 111
 112         writeb((dev << 1) | dir, &I2C->dr);
 113
 114         if (i2c_wait(I2C_WRITE) < 0)
 115                 return 0;
 116
 117         return 1;
 118 }
 119
 120 static __inline__ int
 121 __i2c_write(u8 *data, int length)
 122 {
 123         int i;
 124
 125         writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_MTX,
 126                &I2C->cr);
 127
 128         for (i = 0; i < length; i++) {
 129                 writeb(data[i], &I2C->dr);
 130
 131                 if (i2c_wait(I2C_WRITE) < 0)
 132                         break;
 133         }
 134
 135         return i;
 136 }
 137
 138 static __inline__ int
 139 __i2c_read(u8 *data, int length)
 140 {
 141         int i;
 142
 143         writeb(I2C_CR_MEN | I2C_CR_MSTA | ((length == 1) ? I2C_CR_TXAK : 0),
 144                &I2C->cr);
 145
 146         /* dummy read */
 147         readb(&I2C->dr);
 148
 149         for (i = 0; i < length; i++) {
 150                 if (i2c_wait(I2C_READ) < 0)
 151                         break;
 152
 153                 /* Generate ack on last next to last byte */
 154                 if (i == length - 2)
 155                         writeb(I2C_CR_MEN | I2C_CR_MSTA | I2C_CR_TXAK,
 156                                &I2C->cr);
 157
 158                 /* Generate stop on last byte */
 159                 if (i == length - 1)
 160                         writeb(I2C_CR_MEN | I2C_CR_TXAK, &I2C->cr);
 161
 162                 data[i] = readb(&I2C->dr);
 163         }
 164
 165         return i;
 166 }
 167
 168 int
 169 i2c_read(u8 dev, uint addr, int alen, u8 *data, int length)
 170 {
 171         int i = 0;
 172         u8 *a = (u8*)&addr;
 173
 174         if (i2c_wait4bus() >= 0
 175             && i2c_write_addr(dev, I2C_WRITE, 0) != 0
 176             && __i2c_write(&a[4 - alen], alen) == alen
 177             && i2c_write_addr(dev, I2C_READ, 1) != 0) {
 178                 i = __i2c_read(data, length);
 179         }
 180
 181         writeb(I2C_CR_MEN, &I2C->cr);
 182
 183         if (i == length)
 184             return 0;
 185
 186         return -1;
 187 }
 188
 189 int
 190 i2c_write(u8 dev, uint addr, int alen, u8 *data, int length)
 191 {
 192         int i = 0;
 193         u8 *a = (u8*)&addr;
 194
 195         if (i2c_wait4bus() >= 0
 196             && i2c_write_addr(dev, I2C_WRITE, 0) != 0
 197             && __i2c_write(&a[4 - alen], alen) == alen) {
 198                 i = __i2c_write(data, length);
 199         }
 200
 201         writeb(I2C_CR_MEN, &I2C->cr);
 202
 203         if (i == length)
 204             return 0;
 205
 206         return -1;
 207 }
 208
 209 int
 210 i2c_probe(uchar chip)
 211 {
 212         int tmp;
 213
 214         /*
 215          * Try to read the first location of the chip.  The underlying
 216          * driver doesn't appear to support sending just the chip address
 217          * and looking for an <ACK> back.
 218          */
 219         udelay(10000);
 220
 221         return i2c_read(chip, 0, 1, (uchar *)&tmp, 1);
 222 }
 223
 224 uchar
 225 i2c_reg_read(uchar i2c_addr, uchar reg)
 226 {
 227         uchar buf[1];
 228
 229         i2c_read(i2c_addr, reg, 1, buf, 1);
 230
 231         return buf[0];
 232 }
 233
 234 void
 235 i2c_reg_write(uchar i2c_addr, uchar reg, uchar val)
 236 {
 237         i2c_write(i2c_addr, reg, 1, &val, 1);
 238 }
 239
 240 #endif /* CONFIG_HARD_I2C */
 241 #endif /* CONFIG_FSL_I2C */