firmware/target/arm/tms320dm320/i2c-dm320.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2008 by Maurus Cuelenaere
  11  *
  12  * DM320 I²C driver
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  20  * KIND, either express or implied.
  21  *
  22  ****************************************************************************/
  23 #include "system.h"
  24 #include "thread.h"
  25 #include "i2c-dm320.h"
  26
  27 #define I2C_SCS_COND_START  0x0001
  28 #define I2C_SCS_COND_STOP   0x0002
  29 #define I2C_SCS_XMIT        0x0004
  30
  31 #define I2C_TX_ACK          (1 << 8)
  32
  33 static struct mutex i2c_mtx;
  34
  35 static inline void i2c_begin(void)
  36 {
  37     mutex_lock(&i2c_mtx);
  38 }
  39
  40 static inline void i2c_end(void)
  41 {
  42     mutex_unlock(&i2c_mtx);
  43 }
  44
  45 static inline bool i2c_getack(void)
  46 {
  47     return (IO_I2C_RXDATA >> 8) & 1;
  48 }
  49
  50 static inline void i2c_ack(void)
  51 {
  52     IO_I2C_TXDATA |= I2C_TX_ACK;
  53 }
  54
  55 #define WAIT_FOR_I2C    if(IO_I2C_SCS & 0x4){ \
  56                             while(IO_I2C_SCS & 0x4) { \
  57                                 asm volatile("nop"); \
  58                             } \
  59                         } \
  60
  61 static inline void i2c_start(void)
  62 {
  63     IO_I2C_SCS |= I2C_SCS_XMIT;
  64     return;
  65 }
  66
  67 int i2c_write(unsigned short address, const unsigned char *buf, int count)
  68 {
  69     int i;
  70     int ret=0;
  71     i2c_begin();
  72     IO_I2C_TXDATA = ( (address << 1) & 0xFF ) | (address>0x7F ? 0 : 1 ) | I2C_TX_ACK;
  73     IO_I2C_SCS &= ~0x3; //clear conditions
  74     IO_I2C_SCS |= I2C_SCS_COND_START; // write 'start condition'
  75     i2c_start();
  76     WAIT_FOR_I2C;
  77     /* experimental */
  78     if(address>0x7F){ // check if it is 10-bit instead of 7-bit
  79         IO_I2C_TXDATA = ( (address >> 7) & 0xFF) | I2C_TX_ACK;
  80         IO_I2C_SCS &= ~0x3; //normal transfer
  81         i2c_start();
  82         WAIT_FOR_I2C;
  83         IO_I2C_TXDATA = ( (address << 1) & 0xFF) | 1 | I2C_TX_ACK;
  84         IO_I2C_SCS &= ~0x3; //clear conditions
  85         IO_I2C_SCS |= I2C_SCS_COND_START; //write 'start condition'
  86         i2c_start();
  87         WAIT_FOR_I2C;
  88     }
  89
  90     for(i=0; i<count; i++){
  91         IO_I2C_TXDATA = buf[i] | I2C_TX_ACK;
  92         IO_I2C_SCS &= ~0x3; //normal transfer
  93         i2c_start();
  94         WAIT_FOR_I2C;
  95         if(!i2c_getack())
  96             ret = -1;
  97     }
  98     IO_I2C_SCS &= ~0x3; //clear conditions
  99     IO_I2C_SCS |= I2C_SCS_COND_STOP; //write 'stop condition'
 100     i2c_start();
 101     WAIT_FOR_I2C;
 102     i2c_end();
 103     return ret;
 104 }
 105
 106 int i2c_read(unsigned short address, unsigned char* buf, int count)
 107 {
 108     int i;
 109     int ack=0;
 110     i2c_begin();
 111     IO_I2C_TXDATA = ( (address << 1) & 0xFF ) | (address>0x7F ? 0 : 1 ) | I2C_TX_ACK;
 112     IO_I2C_SCS &= ~0x3; //clear conditions
 113     IO_I2C_SCS |= I2C_SCS_COND_START; // write 'start condition'
 114     i2c_start();
 115     WAIT_FOR_I2C;
 116     /* experimental */
 117     if(address>0x7F){ // check if it is 10-bit instead of 7-bit
 118         IO_I2C_TXDATA = ( (address >> 7) & 0xFF ) | I2C_TX_ACK;
 119         IO_I2C_SCS &= ~0x3; //normal transfer
 120         i2c_start();
 121         WAIT_FOR_I2C;
 122         IO_I2C_TXDATA = ( (address << 1) & 0xFF ) | 1 | I2C_TX_ACK;
 123         IO_I2C_SCS &= ~0x3; //clear conditions
 124         IO_I2C_SCS |= I2C_SCS_COND_START; //write 'start condition'
 125         i2c_start();
 126         WAIT_FOR_I2C;
 127     }
 128
 129     for(i=0; i<count; i++){
 130         unsigned short temp;
 131         IO_I2C_TXDATA = 0xFF | ( (count-1)==i ? I2C_TX_ACK : 0);
 132         IO_I2C_SCS &= ~0x3; //normal transfer
 133         i2c_start();
 134         WAIT_FOR_I2C;
 135         temp = IO_I2C_RXDATA;
 136         buf[i] = temp & 0xFF;
 137         ack = (temp & 0x100) >> 8;
 138     }
 139     IO_I2C_SCS &= ~0x3; //clear conditions
 140     IO_I2C_SCS |= I2C_SCS_COND_STOP; //write 'stop condition'
 141     i2c_start();
 142     WAIT_FOR_I2C;
 143     i2c_end();
 144     return ack;
 145 }
 146
 147 void i2c_init(void)
 148 {
 149     mutex_init(&i2c_mtx);
 150
 151 #ifdef CREATIVE_ZVx //TODO: mimic OF I2C clock settings; currently this is done by the bootloader
 152     IO_CLK_MOD2 &= ~CLK_MOD2_I2C; // turn I²C clock off (just to be sure)
 153     IO_CLK_LPCTL1 &= ~1; // set Powerdown mode to off
 154     IO_CLK_SEL0 &= ~0x800; // set I²C clock to PLLA
 155     IO_CLK_DIV4 &= ~0x1F; // I²C clock division = 1
 156     IO_CLK_MOD2 |= CLK_MOD2_I2C; // enable I²C clock
 157 #endif
 158     IO_I2C_SCS &= ~0x8; //set clock to 100 kHz
 159     IO_INTC_EINT2 &= ~INTR_EINT2_I2C; // disable I²C interrupt
 160 }