arch/powerpc/cpu/mpc824x/drivers/i2c/i2c.c

   1 /*
   2  * (C) Copyright 2003
   3  * Gleb Natapov <gnatapov@mrv.com>
   4  * Some bits are taken from linux driver writen by adrian@humboldt.co.uk
   5  *
   6  * Hardware I2C driver for MPC107 PCI bridge.
   7  *
   8  * See file CREDITS for list of people who contributed to this
   9  * project.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of
  14  * the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  24  * MA 02111-1307 USA
  25  */
  26
  27 #include <common.h>
  28
  29 #undef I2CDBG
  30
  31 #ifdef CONFIG_HARD_I2C
  32 #include <i2c.h>
  33
  34 #define TIMEOUT (CONFIG_SYS_HZ/4)
  35
  36 #define I2C_Addr ((unsigned *)(CONFIG_SYS_EUMB_ADDR + 0x3000))
  37
  38 #define I2CADR &I2C_Addr[0]
  39 #define I2CFDR  &I2C_Addr[1]
  40 #define I2CCCR  &I2C_Addr[2]
  41 #define I2CCSR  &I2C_Addr[3]
  42 #define I2CCDR  &I2C_Addr[4]
  43
  44 #define MPC107_CCR_MEN  0x80
  45 #define MPC107_CCR_MIEN 0x40
  46 #define MPC107_CCR_MSTA 0x20
  47 #define MPC107_CCR_MTX  0x10
  48 #define MPC107_CCR_TXAK 0x08
  49 #define MPC107_CCR_RSTA 0x04
  50
  51 #define MPC107_CSR_MCF  0x80
  52 #define MPC107_CSR_MAAS 0x40
  53 #define MPC107_CSR_MBB  0x20
  54 #define MPC107_CSR_MAL  0x10
  55 #define MPC107_CSR_SRW  0x04
  56 #define MPC107_CSR_MIF  0x02
  57 #define MPC107_CSR_RXAK 0x01
  58
  59 #define I2C_READ  1
  60 #define I2C_WRITE 0
  61
  62 /* taken from linux include/asm-ppc/io.h */
  63 inline unsigned in_le32 (volatile unsigned *addr)
  64 {
  65         unsigned ret;
  66
  67         __asm__ __volatile__ ("lwbrx %0,0,%1;\n"
  68                               "twi 0,%0,0;\n"
  69                               "isync":"=r" (ret): "r" (addr), "m" (*addr));
  70         return ret;
  71 }
  72
  73 inline void out_le32 (volatile unsigned *addr, int val)
  74 {
  75         __asm__ __volatile__ ("stwbrx %1,0,%2; eieio":"=m" (*addr):"r" (val),
  76                               "r" (addr));
  77 }
  78
  79 #define writel(val, addr) out_le32(addr, val)
  80 #define readl(addr) in_le32(addr)
  81
  82 void i2c_init (int speed, int slaveadd)
  83 {
  84         /* stop I2C controller */
  85         writel (0x0, I2CCCR);
  86         /* set clock */
  87         writel (0x1020, I2CFDR);
  88         /* write slave address */
  89         writel (slaveadd, I2CADR);
  90         /* clear status register */
  91         writel (0x0, I2CCSR);
  92         /* start I2C controller */
  93         writel (MPC107_CCR_MEN, I2CCCR);
  94
  95         return;
  96 }
  97
  98 static __inline__ int i2c_wait4bus (void)
  99 {
 100         ulong timeval = get_timer (0);
 101
 102         while (readl (I2CCSR) & MPC107_CSR_MBB)
 103                 if (get_timer (timeval) > TIMEOUT)
 104                         return -1;
 105
 106         return 0;
 107 }
 108
 109 static __inline__ int i2c_wait (int write)
 110 {
 111         u32 csr;
 112         ulong timeval = get_timer (0);
 113
 114         do {
 115                 csr = readl (I2CCSR);
 116
 117                 if (!(csr & MPC107_CSR_MIF))
 118                         continue;
 119
 120                 writel (0x0, I2CCSR);
 121
 122                 if (csr & MPC107_CSR_MAL) {
 123 #ifdef I2CDBG
 124                         printf ("i2c_wait: MAL\n");
 125 #endif
 126                         return -1;
 127                 }
 128
 129                 if (!(csr & MPC107_CSR_MCF)) {
 130 #ifdef I2CDBG
 131                         printf ("i2c_wait: unfinished\n");
 132 #endif
 133                         return -1;
 134                 }
 135
 136                 if (write == I2C_WRITE && (csr & MPC107_CSR_RXAK)) {
 137 #ifdef I2CDBG
 138                         printf ("i2c_wait: No RXACK\n");
 139 #endif
 140                         return -1;
 141                 }
 142
 143                 return 0;
 144         } while (get_timer (timeval) < TIMEOUT);
 145
 146 #ifdef I2CDBG
 147         printf ("i2c_wait: timed out\n");
 148 #endif
 149         return -1;
 150 }
 151
 152 static __inline__ int i2c_write_addr (u8 dev, u8 dir, int rsta)
 153 {
 154         writel (MPC107_CCR_MEN | MPC107_CCR_MSTA | MPC107_CCR_MTX |
 155                 (rsta ? MPC107_CCR_RSTA : 0), I2CCCR);
 156
 157         writel ((dev << 1) | dir, I2CCDR);
 158
 159         if (i2c_wait (I2C_WRITE) < 0)
 160                 return 0;
 161
 162         return 1;
 163 }
 164
 165 static __inline__ int __i2c_write (u8 * data, int length)
 166 {
 167         int i;
 168
 169         writel (MPC107_CCR_MEN | MPC107_CCR_MSTA | MPC107_CCR_MTX, I2CCCR);
 170
 171         for (i = 0; i < length; i++) {
 172                 writel (data[i], I2CCDR);
 173
 174                 if (i2c_wait (I2C_WRITE) < 0)
 175                         break;
 176         }
 177
 178         return i;
 179 }
 180
 181 static __inline__ int __i2c_read (u8 * data, int length)
 182 {
 183         int i;
 184
 185         writel (MPC107_CCR_MEN | MPC107_CCR_MSTA |
 186                 ((length == 1) ? MPC107_CCR_TXAK : 0), I2CCCR);
 187
 188         /* dummy read */
 189         readl (I2CCDR);
 190
 191         for (i = 0; i < length; i++) {
 192                 if (i2c_wait (I2C_READ) < 0)
 193                         break;
 194
 195                 /* Generate ack on last next to last byte */
 196                 if (i == length - 2)
 197                         writel (MPC107_CCR_MEN | MPC107_CCR_MSTA |
 198                                 MPC107_CCR_TXAK, I2CCCR);
 199
 200                 /* Generate stop on last byte */
 201                 if (i == length - 1)
 202                         writel (MPC107_CCR_MEN | MPC107_CCR_TXAK, I2CCCR);
 203
 204                 data[i] = readl (I2CCDR);
 205         }
 206
 207         return i;
 208 }
 209
 210 int i2c_read (u8 dev, uint addr, int alen, u8 * data, int length)
 211 {
 212         int i = 0;
 213         u8 *a = (u8 *) & addr;
 214
 215         if (i2c_wait4bus () < 0)
 216                 goto exit;
 217
 218         if (i2c_write_addr (dev, I2C_WRITE, 0) == 0)
 219                 goto exit;
 220
 221         if (__i2c_write (&a[4 - alen], alen) != alen)
 222                 goto exit;
 223
 224         if (i2c_write_addr (dev, I2C_READ, 1) == 0)
 225                 goto exit;
 226
 227         i = __i2c_read (data, length);
 228
 229 exit:
 230         writel (MPC107_CCR_MEN, I2CCCR);
 231
 232         return !(i == length);
 233 }
 234
 235 int i2c_write (u8 dev, uint addr, int alen, u8 * data, int length)
 236 {
 237         int i = 0;
 238         u8 *a = (u8 *) & addr;
 239
 240         if (i2c_wait4bus () < 0)
 241                 goto exit;
 242
 243         if (i2c_write_addr (dev, I2C_WRITE, 0) == 0)
 244                 goto exit;
 245
 246         if (__i2c_write (&a[4 - alen], alen) != alen)
 247                 goto exit;
 248
 249         i = __i2c_write (data, length);
 250
 251 exit:
 252         writel (MPC107_CCR_MEN, I2CCCR);
 253
 254         return !(i == length);
 255 }
 256
 257 int i2c_probe (uchar chip)
 258 {
 259         int tmp;
 260
 261         /*
 262          * Try to read the first location of the chip.  The underlying
 263          * driver doesn't appear to support sending just the chip address
 264          * and looking for an <ACK> back.
 265          */
 266         udelay (10000);
 267         return i2c_read (chip, 0, 1, (uchar *) &tmp, 1);
 268 }
 269
 270 #endif /* CONFIG_HARD_I2C */