cpu/mips/jz_i2c.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify it
   3  * under the terms of the GNU General Public License as published by the
   4  * Free Software Foundation; either version 2 of the License, or (at your
   5  * option) any later version.
   6  */
   7
   8
   9 #include <config.h>
  10
  11 #if defined(CONFIG_JZ4730) || defined(CONFIG_JZ4740) || defined(CONFIG_JZ5730)
  12
  13 #include <common.h>
  14 #include <malloc.h>
  15 #include <net.h>
  16 #include <command.h>
  17 #include <asm/io.h>
  18 #if defined(CONFIG_JZ4730)
  19 #include <asm/jz4730.h>
  20 #endif
  21 #if defined(CONFIG_JZ4740)
  22 #include <asm/jz4740.h>
  23 #endif
  24 #if defined(CONFIG_JZ5730)
  25 #include <asm/jz5730.h>
  26 #endif
  27
  28
  29 /* I2C protocol */
  30 #define I2C_READ        1
  31 #define I2C_WRITE       0
  32
  33 #define TIMEOUT         1000
  34
  35 #define ETIMEDOUT 1
  36
  37
  38 static inline void my_udelay(int n )
  39 {
  40         int i;
  41         i=n*100;
  42         while ( i-- )
  43                 ;
  44 }
  45
  46
  47 /*
  48  * I2C bus protocol basic routines
  49  */
  50 static int i2c_put_data(unsigned char data)
  51 {
  52         unsigned int timeout = TIMEOUT*10;
  53
  54         __i2c_write(data);
  55         __i2c_set_drf();
  56         while (__i2c_check_drf() != 0);
  57         while (!__i2c_transmit_ended());
  58         while (!__i2c_received_ack() && timeout)
  59                 timeout--;
  60
  61         if (timeout)
  62                 return 0;
  63         else
  64                 return -ETIMEDOUT;
  65 }
  66
  67 static int i2c_get_data(unsigned char *data, int ack)
  68 {
  69         int timeout = TIMEOUT*10;
  70
  71         if (!ack)
  72                 __i2c_send_nack();
  73         else
  74                 __i2c_send_ack();
  75
  76         while (__i2c_check_drf() == 0 && timeout)
  77                 timeout--;
  78
  79         if (timeout) {
  80                 if (!ack)
  81                         __i2c_send_stop();
  82                 *data = __i2c_read();
  83                 __i2c_clear_drf();
  84                 return 0;
  85         } else
  86                 return -ETIMEDOUT;
  87 }
  88
  89 /*
  90  * I2C interface
  91  */
  92 void i2c_open(void)
  93 {
  94         __i2c_set_clk(CFG_EXTAL, 10000); /* default 10 KHz */
  95         __i2c_enable();
  96 }
  97
  98 void i2c_close(void)
  99 {
 100         my_udelay(300); /* wait for STOP goes over. */
 101         __i2c_disable();
 102 }
 103
 104 void i2c_setclk(unsigned int i2cclk)
 105 {
 106         __i2c_set_clk(CFG_EXTAL, i2cclk);
 107 }
 108
 109 int i2c_lseek(unsigned char device, unsigned char offset)
 110 {
 111         __i2c_send_nack();      /* Master does not send ACK, slave sends it */
 112         __i2c_send_start();
 113         if (i2c_put_data( (device << 1) | I2C_WRITE ) < 0)
 114                 goto device_err;
 115         if (i2c_put_data(offset) < 0)
 116                 goto address_err;
 117         return 0;
 118  device_err:
 119         printf("No I2C device (0x%02x) installed.\n", device);
 120         __i2c_send_stop();
 121         return -1;
 122  address_err:
 123         printf("No I2C device (0x%02x) response.\n", device);
 124         __i2c_send_stop();
 125         return -1;
 126 }
 127
 128 int i2c_read(unsigned char device, unsigned char *buf,
 129                unsigned char address, int count)
 130 {
 131         int cnt = count;
 132         int timeout = 5;
 133
 134 L_try_again:
 135
 136         if (timeout < 0)
 137                 goto L_timeout;
 138
 139         __i2c_send_nack();      /* Master does not send ACK, slave sends it */
 140         __i2c_send_start();
 141         if (i2c_put_data( (device << 1) | I2C_WRITE ) < 0)
 142                 goto device_werr;
 143         if (i2c_put_data(address) < 0)
 144                 goto address_err;
 145
 146         __i2c_send_start();
 147         if (i2c_put_data( (device << 1) | I2C_READ ) < 0)
 148                 goto device_rerr;
 149         __i2c_send_ack();       /* Master sends ACK for continue reading */
 150         while (cnt) {
 151                 if (cnt == 1) {
 152                         if (i2c_get_data(buf, 0) < 0)
 153                                 break;
 154                 } else {
 155                         if (i2c_get_data(buf, 1) < 0)
 156                                 break;
 157                 }
 158                 cnt--;
 159                 buf++;
 160         }
 161
 162         __i2c_send_stop();
 163         return count - cnt;
 164  device_rerr:
 165  device_werr:
 166  address_err:
 167         timeout --;
 168         __i2c_send_stop();
 169         goto L_try_again;
 170
 171 L_timeout:
 172         __i2c_send_stop();
 173         printf("Read I2C device 0x%2x failed.\n", device);
 174         return -1;
 175 }
 176
 177 int i2c_write(unsigned char device, unsigned char *buf,
 178                 unsigned char address, int count)
 179 {
 180         int cnt = count;
 181         int cnt_in_pg;
 182         int timeout = 5;
 183         unsigned char *tmpbuf;
 184         unsigned char tmpaddr;
 185
 186         __i2c_send_nack();      /* Master does not send ACK, slave sends it */
 187
 188  W_try_again:
 189         if (timeout < 0)
 190                 goto W_timeout;
 191
 192         cnt = count;
 193         tmpbuf = (unsigned char *)buf;
 194         tmpaddr = address;
 195
 196  start_write_page:
 197         cnt_in_pg = 0;
 198         __i2c_send_start();
 199         if (i2c_put_data( (device << 1) | I2C_WRITE ) < 0)
 200                 goto device_err;
 201         if (i2c_put_data(tmpaddr) < 0)
 202                 goto address_err;
 203         while (cnt) {
 204                 if (++cnt_in_pg > 8) {
 205                         __i2c_send_stop();
 206                         my_udelay(1000);
 207                         tmpaddr += 8;
 208                         goto start_write_page;
 209                 }
 210                 if (i2c_put_data(*tmpbuf) < 0)
 211                         break;
 212                 cnt--;
 213                 tmpbuf++;
 214         }
 215         __i2c_send_stop();
 216         return count - cnt;
 217  device_err:
 218  address_err:
 219         timeout--;
 220         __i2c_send_stop();
 221         goto W_try_again;
 222
 223  W_timeout:
 224         printf("Write I2C device 0x%2x failed.\n", device);
 225         __i2c_send_stop();
 226         return -1;
 227 }
 228
 229 #endif /* CONFIG_JZ4730 || CONFIG_JZ4740 || CONFIG_JZ5730 */
 230
 231