cpu/mpc85xx/i2c.c

   1 /*
   2  * (C) Copyright 2003,Motorola Inc.
   3  * Xianghua Xiao <x.xiao@motorola.com>
   4  * Adapted for Motorola 85xx chip.
   5  *
   6  * (C) Copyright 2003
   7  * Gleb Natapov <gnatapov@mrv.com>
   8  * Some bits are taken from linux driver writen by adrian@humboldt.co.uk
   9  *
  10  * Hardware I2C driver for MPC107 PCI bridge.
  11  *
  12  * See file CREDITS for list of people who contributed to this
  13  * project.
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License as
  17  * published by the Free Software Foundation; either version 2 of
  18  * the License, or (at your option) any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  * GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with this program; if not, write to the Free Software
  27  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  28  * MA 02111-1307 USA
  29  */
  30
  31 #include <common.h>
  32 #include <command.h>
  33 #include <asm/io.h>
  34
  35 #ifdef CONFIG_HARD_I2C
  36 #include <i2c.h>
  37
  38 #define TIMEOUT (CFG_HZ/4)
  39
  40 #define I2C_Addr ((u8 *)(CFG_CCSRBAR + 0x3000))
  41
  42 #define I2CADR  &I2C_Addr[0]
  43 #define I2CFDR  &I2C_Addr[4]
  44 #define I2CCCR  &I2C_Addr[8]
  45 #define I2CCSR  &I2C_Addr[12]
  46 #define I2CCDR  &I2C_Addr[16]
  47 #define I2CDFSRR &I2C_Addr[20]
  48
  49 #define I2C_READ  1
  50 #define I2C_WRITE 0
  51
  52 void
  53 i2c_init(int speed, int slaveadd)
  54 {
  55         /* stop I2C controller */
  56         writeb(0x0, I2CCCR);
  57
  58         /* set clock */
  59         writeb(0x3f, I2CFDR);
  60
  61         /* set default filter */
  62         writeb(0x10,I2CDFSRR);
  63
  64         /* write slave address */
  65         writeb(slaveadd, I2CADR);
  66
  67         /* clear status register */
  68         writeb(0x0, I2CCSR);
  69
  70         /* start I2C controller */
  71         writeb(MPC85xx_I2CCR_MEN, I2CCCR);
  72 }
  73
  74 static __inline__ int
  75 i2c_wait4bus (void)
  76 {
  77         ulong timeval = get_timer (0);
  78
  79         while (readb(I2CCSR) & MPC85xx_I2CSR_MBB) {
  80                 if (get_timer (timeval) > TIMEOUT) {
  81                         return -1;
  82                 }
  83         }
  84
  85   return 0;
  86 }
  87
  88 static __inline__ int
  89 i2c_wait (int write)
  90 {
  91         u32 csr;
  92         ulong timeval = get_timer (0);
  93
  94         do {
  95                 csr = readb(I2CCSR);
  96
  97                 if (!(csr & MPC85xx_I2CSR_MIF))
  98                         continue;
  99
 100                 writeb(0x0, I2CCSR);
 101
 102                 if (csr & MPC85xx_I2CSR_MAL) {
 103                         debug("i2c_wait: MAL\n");
 104                         return -1;
 105                 }
 106
 107                 if (!(csr & MPC85xx_I2CSR_MCF)) {
 108                         debug("i2c_wait: unfinished\n");
 109                         return -1;
 110                 }
 111
 112                 if (write == I2C_WRITE && (csr & MPC85xx_I2CSR_RXAK)) {
 113                         debug("i2c_wait: No RXACK\n");
 114                         return -1;
 115                 }
 116
 117                 return 0;
 118         } while (get_timer (timeval) < TIMEOUT);
 119
 120         debug("i2c_wait: timed out\n");
 121         return -1;
 122 }
 123
 124 static __inline__ int
 125 i2c_write_addr (u8 dev, u8 dir, int rsta)
 126 {
 127         writeb(MPC85xx_I2CCR_MEN | MPC85xx_I2CCR_MSTA | MPC85xx_I2CCR_MTX |
 128                (rsta?MPC85xx_I2CCR_RSTA:0),
 129                I2CCCR);
 130
 131         writeb((dev << 1) | dir, I2CCDR);
 132
 133         if (i2c_wait (I2C_WRITE) < 0)
 134                 return 0;
 135
 136         return 1;
 137 }
 138
 139 static __inline__ int
 140 __i2c_write (u8 *data, int length)
 141 {
 142         int i;
 143
 144         writeb(MPC85xx_I2CCR_MEN | MPC85xx_I2CCR_MSTA | MPC85xx_I2CCR_MTX,
 145                I2CCCR);
 146
 147         for (i=0; i < length; i++) {
 148                 writeb(data[i], I2CCDR);
 149
 150                 if (i2c_wait (I2C_WRITE) < 0)
 151                         break;
 152         }
 153
 154         return i;
 155 }
 156
 157 static __inline__ int
 158 __i2c_read (u8 *data, int length)
 159 {
 160         int i;
 161
 162         writeb(MPC85xx_I2CCR_MEN | MPC85xx_I2CCR_MSTA |
 163                ((length == 1) ? MPC85xx_I2CCR_TXAK : 0),
 164                I2CCCR);
 165
 166         /* dummy read */
 167         readb(I2CCDR);
 168
 169         for (i=0; i < length; i++) {
 170                 if (i2c_wait (I2C_READ) < 0)
 171                         break;
 172
 173                 /* Generate ack on last next to last byte */
 174                 if (i == length - 2)
 175                         writeb(MPC85xx_I2CCR_MEN | MPC85xx_I2CCR_MSTA |
 176                                MPC85xx_I2CCR_TXAK,
 177                                I2CCCR);
 178
 179                 /* Generate stop on last byte */
 180                 if (i == length - 1)
 181                         writeb(MPC85xx_I2CCR_MEN | MPC85xx_I2CCR_TXAK, I2CCCR);
 182
 183                 data[i] = readb(I2CCDR);
 184         }
 185
 186         return i;
 187 }
 188
 189 int
 190 i2c_read (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                 goto exit;
 197
 198         if (i2c_write_addr (dev, I2C_WRITE, 0) == 0)
 199                 goto exit;
 200
 201         if (__i2c_write (&a[4 - alen], alen) != alen)
 202                 goto exit;
 203
 204         if (i2c_write_addr (dev, I2C_READ, 1) == 0)
 205                 goto exit;
 206
 207         i = __i2c_read (data, length);
 208
 209  exit:
 210         writeb(MPC85xx_I2CCR_MEN, I2CCCR);
 211
 212         return !(i == length);
 213 }
 214
 215 int
 216 i2c_write (u8 dev, uint addr, int alen, u8 *data, int length)
 217 {
 218         int i = 0;
 219         u8 *a = (u8*)&addr;
 220
 221         if (i2c_wait4bus () < 0)
 222                 goto exit;
 223
 224         if (i2c_write_addr (dev, I2C_WRITE, 0) == 0)
 225                 goto exit;
 226
 227         if (__i2c_write (&a[4 - alen], alen) != alen)
 228                 goto exit;
 229
 230         i = __i2c_write (data, length);
 231
 232  exit:
 233         writeb(MPC85xx_I2CCR_MEN, I2CCCR);
 234
 235         return !(i == length);
 236 }
 237
 238 int i2c_probe (uchar chip)
 239 {
 240         int tmp;
 241
 242         /*
 243          * Try to read the first location of the chip.  The underlying
 244          * driver doesn't appear to support sending just the chip address
 245          * and looking for an <ACK> back.
 246          */
 247         udelay(10000);
 248         return i2c_read (chip, 0, 1, (uchar *)&tmp, 1);
 249 }
 250
 251 uchar i2c_reg_read (uchar i2c_addr, uchar reg)
 252 {
 253         uchar buf[1];
 254
 255         i2c_read (i2c_addr, reg, 1, buf, 1);
 256
 257         return (buf[0]);
 258 }
 259
 260 void i2c_reg_write (uchar i2c_addr, uchar reg, uchar val)
 261 {
 262         i2c_write (i2c_addr, reg, 1, &val, 1);
 263 }
 264
 265 #endif /* CONFIG_HARD_I2C */