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  * SPDX-License-Identifier:     GPL-2.0+
   9  */
  10
  11 #include <common.h>
  12
  13 #undef I2CDBG
  14
  15 #ifdef CONFIG_HARD_I2C
  16 #include <i2c.h>
  17
  18 #define TIMEOUT (CONFIG_SYS_HZ/4)
  19
  20 #define I2C_Addr ((unsigned *)(CONFIG_SYS_EUMB_ADDR + 0x3000))
  21
  22 #define I2CADR &I2C_Addr[0]
  23 #define I2CFDR  &I2C_Addr[1]
  24 #define I2CCCR  &I2C_Addr[2]
  25 #define I2CCSR  &I2C_Addr[3]
  26 #define I2CCDR  &I2C_Addr[4]
  27
  28 #define MPC107_CCR_MEN  0x80
  29 #define MPC107_CCR_MIEN 0x40
  30 #define MPC107_CCR_MSTA 0x20
  31 #define MPC107_CCR_MTX  0x10
  32 #define MPC107_CCR_TXAK 0x08
  33 #define MPC107_CCR_RSTA 0x04
  34
  35 #define MPC107_CSR_MCF  0x80
  36 #define MPC107_CSR_MAAS 0x40
  37 #define MPC107_CSR_MBB  0x20
  38 #define MPC107_CSR_MAL  0x10
  39 #define MPC107_CSR_SRW  0x04
  40 #define MPC107_CSR_MIF  0x02
  41 #define MPC107_CSR_RXAK 0x01
  42
  43 #define I2C_READ  1
  44 #define I2C_WRITE 0
  45
  46 /* taken from linux include/asm-ppc/io.h */
  47 inline unsigned in_le32 (volatile unsigned *addr)
  48 {
  49         unsigned ret;
  50
  51         __asm__ __volatile__ ("lwbrx %0,0,%1;\n"
  52                               "twi 0,%0,0;\n"
  53                               "isync":"=r" (ret): "r" (addr), "m" (*addr));
  54         return ret;
  55 }
  56
  57 inline void out_le32 (volatile unsigned *addr, int val)
  58 {
  59         __asm__ __volatile__ ("stwbrx %1,0,%2; eieio":"=m" (*addr):"r" (val),
  60                               "r" (addr));
  61 }
  62
  63 #define writel(val, addr) out_le32(addr, val)
  64 #define readl(addr) in_le32(addr)
  65
  66 void i2c_init (int speed, int slaveadd)
  67 {
  68         /* stop I2C controller */
  69         writel (0x0, I2CCCR);
  70         /* set clock */
  71         writel (0x1020, I2CFDR);
  72         /* write slave address */
  73         writel (slaveadd, I2CADR);
  74         /* clear status register */
  75         writel (0x0, I2CCSR);
  76         /* start I2C controller */
  77         writel (MPC107_CCR_MEN, I2CCCR);
  78
  79         return;
  80 }
  81
  82 static __inline__ int i2c_wait4bus (void)
  83 {
  84         ulong timeval = get_timer (0);
  85
  86         while (readl (I2CCSR) & MPC107_CSR_MBB)
  87                 if (get_timer (timeval) > TIMEOUT)
  88                         return -1;
  89
  90         return 0;
  91 }
  92
  93 static __inline__ int i2c_wait (int write)
  94 {
  95         u32 csr;
  96         ulong timeval = get_timer (0);
  97
  98         do {
  99                 csr = readl (I2CCSR);
 100
 101                 if (!(csr & MPC107_CSR_MIF))
 102                         continue;
 103
 104                 writel (0x0, I2CCSR);
 105
 106                 if (csr & MPC107_CSR_MAL) {
 107 #ifdef I2CDBG
 108                         printf ("i2c_wait: MAL\n");
 109 #endif
 110                         return -1;
 111                 }
 112
 113                 if (!(csr & MPC107_CSR_MCF)) {
 114 #ifdef I2CDBG
 115                         printf ("i2c_wait: unfinished\n");
 116 #endif
 117                         return -1;
 118                 }
 119
 120                 if (write == I2C_WRITE && (csr & MPC107_CSR_RXAK)) {
 121 #ifdef I2CDBG
 122                         printf ("i2c_wait: No RXACK\n");
 123 #endif
 124                         return -1;
 125                 }
 126
 127                 return 0;
 128         } while (get_timer (timeval) < TIMEOUT);
 129
 130 #ifdef I2CDBG
 131         printf ("i2c_wait: timed out\n");
 132 #endif
 133         return -1;
 134 }
 135
 136 static __inline__ int i2c_write_addr (u8 dev, u8 dir, int rsta)
 137 {
 138         writel (MPC107_CCR_MEN | MPC107_CCR_MSTA | MPC107_CCR_MTX |
 139                 (rsta ? MPC107_CCR_RSTA : 0), I2CCCR);
 140
 141         writel ((dev << 1) | dir, I2CCDR);
 142
 143         if (i2c_wait (I2C_WRITE) < 0)
 144                 return 0;
 145
 146         return 1;
 147 }
 148
 149 static __inline__ int __i2c_write (u8 * data, int length)
 150 {
 151         int i;
 152
 153         writel (MPC107_CCR_MEN | MPC107_CCR_MSTA | MPC107_CCR_MTX, I2CCCR);
 154
 155         for (i = 0; i < length; i++) {
 156                 writel (data[i], I2CCDR);
 157
 158                 if (i2c_wait (I2C_WRITE) < 0)
 159                         break;
 160         }
 161
 162         return i;
 163 }
 164
 165 static __inline__ int __i2c_read (u8 * data, int length)
 166 {
 167         int i;
 168
 169         writel (MPC107_CCR_MEN | MPC107_CCR_MSTA |
 170                 ((length == 1) ? MPC107_CCR_TXAK : 0), I2CCCR);
 171
 172         /* dummy read */
 173         readl (I2CCDR);
 174
 175         for (i = 0; i < length; i++) {
 176                 if (i2c_wait (I2C_READ) < 0)
 177                         break;
 178
 179                 /* Generate ack on last next to last byte */
 180                 if (i == length - 2)
 181                         writel (MPC107_CCR_MEN | MPC107_CCR_MSTA |
 182                                 MPC107_CCR_TXAK, I2CCCR);
 183
 184                 /* Generate stop on last byte */
 185                 if (i == length - 1)
 186                         writel (MPC107_CCR_MEN | MPC107_CCR_TXAK, I2CCCR);
 187
 188                 data[i] = readl (I2CCDR);
 189         }
 190
 191         return i;
 192 }
 193
 194 int i2c_read (u8 dev, uint addr, int alen, u8 * data, int length)
 195 {
 196         int i = 0;
 197         u8 *a = (u8 *) & addr;
 198
 199         if (i2c_wait4bus () < 0)
 200                 goto exit;
 201
 202         if (i2c_write_addr (dev, I2C_WRITE, 0) == 0)
 203                 goto exit;
 204
 205         if (__i2c_write (&a[4 - alen], alen) != alen)
 206                 goto exit;
 207
 208         if (i2c_write_addr (dev, I2C_READ, 1) == 0)
 209                 goto exit;
 210
 211         i = __i2c_read (data, length);
 212
 213 exit:
 214         writel (MPC107_CCR_MEN, I2CCCR);
 215
 216         return !(i == length);
 217 }
 218
 219 int i2c_write (u8 dev, uint addr, int alen, u8 * data, int length)
 220 {
 221         int i = 0;
 222         u8 *a = (u8 *) & addr;
 223
 224         if (i2c_wait4bus () < 0)
 225                 goto exit;
 226
 227         if (i2c_write_addr (dev, I2C_WRITE, 0) == 0)
 228                 goto exit;
 229
 230         if (__i2c_write (&a[4 - alen], alen) != alen)
 231                 goto exit;
 232
 233         i = __i2c_write (data, length);
 234
 235 exit:
 236         writel (MPC107_CCR_MEN, I2CCCR);
 237
 238         return !(i == length);
 239 }
 240
 241 int i2c_probe (uchar chip)
 242 {
 243         int tmp;
 244
 245         /*
 246          * Try to read the first location of the chip.  The underlying
 247          * driver doesn't appear to support sending just the chip address
 248          * and looking for an <ACK> back.
 249          */
 250         udelay (10000);
 251         return i2c_read (chip, 0, 1, (uchar *) &tmp, 1);
 252 }
 253
 254 #endif /* CONFIG_HARD_I2C */