[7be6ad9] | 1 | /* GT64260TWSI.c : Two-Wire Serial Interface (TWSI) support for the GT64260 |
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| 2 | * |
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| 3 | * Copyright (c) 2004, Brookhaven National Laboratory and |
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| 4 | * Shuchen Kate Feng <feng1@bnl.gov> |
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| 5 | * All rights reserved. |
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| 6 | * |
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| 7 | * The license and distribution terms for this file may be |
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| 8 | * found in the file LICENSE in this distribution. |
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| 9 | * |
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| 10 | * See section 24:TWSI interface of "the GT-64260B System Controller |
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| 11 | * for powerPc Processors Data Sheet". |
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| 12 | * |
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| 13 | * For full TWSI protocol description look in Philips Semiconductor |
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| 14 | * TWSI spec. |
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| 15 | * |
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| 16 | * We need it to read out I2C devices used for the MVME5500 |
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| 17 | * (eg. the memory SPD and VPD). |
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| 18 | * |
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| 19 | */ |
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| 20 | #include <libcpu/spr.h> /*registers.h included here for rtems_bsp_delay()*/ |
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| 21 | #include <libcpu/io.h> |
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| 22 | #include <rtems/bspIo.h> /* printk */ |
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| 23 | |
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| 24 | #include "bsp/gtreg.h" |
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| 25 | #include "bsp/GT64260TWSI.h" |
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| 26 | |
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| 27 | #define MAX_LOOP 100 |
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| 28 | |
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| 29 | #define TWSI_DEBUG 0 |
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| 30 | |
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| 31 | int TWSI_initFlg = 0; /* TWSI Initialization Flag */ |
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| 32 | |
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| 33 | void GT64260TWSIinit() |
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| 34 | { |
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| 35 | |
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| 36 | if ( !TWSI_initFlg) { |
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| 37 | #if TWSI_DEBUG |
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| 38 | printk("GT64260TWSIinit("); |
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| 39 | #endif |
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| 40 | outl( 0, TWSI_SFT_RST); /* soft reset */ |
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| 41 | rtems_bsp_delay(1000); |
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| 42 | |
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| 43 | /* See 24.2.5 : Assume bus speed is 133MHZ |
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| 44 | * Try to be close to the default frequency : 62.5KHZ |
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| 45 | * value 0x2c: 69.27 KHz TWSI bus clock |
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| 46 | */ |
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| 47 | outl(0x2c, TWSI_BAUDE_RATE); |
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| 48 | rtems_bsp_delay(1000); |
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| 49 | |
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| 50 | /* Set Acknowledge and enable TWSI in the Control register */ |
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| 51 | outl(0x44, TWSI_CTRL); |
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| 52 | rtems_bsp_delay(4000); |
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| 53 | TWSI_initFlg = 1; |
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| 54 | #if TWSI_DEBUG |
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| 55 | printk(")\n"); |
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| 56 | #endif |
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| 57 | } |
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| 58 | } |
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| 59 | |
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| 60 | /* return the interrupt flag */ |
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| 61 | int GT64260TWSIintFlag() |
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| 62 | { |
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| 63 | unsigned int loop; |
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| 64 | |
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| 65 | for (loop = 0; loop < MAX_LOOP; loop++ ) { |
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| 66 | /* Return 1 if the interrupt flag is set */ |
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| 67 | if (inl(TWSI_CTRL) & TWSI_INTFLG) return(1); |
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| 68 | rtems_bsp_delay(1000); |
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| 69 | } |
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| 70 | return(0); |
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| 71 | } |
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| 72 | |
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| 73 | int GT64260TWSIstop() |
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| 74 | { |
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| 75 | |
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| 76 | #if TWSI_DEBUG |
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| 77 | printk("GT64260TWSIstop("); |
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| 78 | #endif |
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| 79 | |
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| 80 | outl((inl(TWSI_CTRL) | TWSI_STOP), TWSI_CTRL); |
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| 81 | rtems_bsp_delay(1000); |
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| 82 | |
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| 83 | /* Check if interrupt flag bit is set*/ |
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| 84 | if (GT64260TWSIintFlag()) { |
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| 85 | outl((inl( TWSI_CTRL) & ~TWSI_INTFLG), TWSI_CTRL); |
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| 86 | rtems_bsp_delay(1000); |
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| 87 | #if TWSI_DEBUG |
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| 88 | printk(")\n"); |
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| 89 | #endif |
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| 90 | return(0); |
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| 91 | } |
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| 92 | #if TWSI_DEBUG |
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| 93 | printk("NoIntFlag\n"); |
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| 94 | #endif |
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| 95 | return(-1); |
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| 96 | } |
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| 97 | |
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| 98 | int GT64260TWSIstart() |
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| 99 | { |
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| 100 | unsigned int loop; |
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| 101 | unsigned int status; |
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| 102 | |
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| 103 | #if TWSI_DEBUG |
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| 104 | printk("GT64260TWSIstart("); |
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| 105 | #endif |
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| 106 | /* Initialize the TWSI interface */ |
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| 107 | GT64260TWSIinit(); |
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| 108 | |
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| 109 | /* set the start bit */ |
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| 110 | outl((TWSI_START | TWSI_TWSIEN), TWSI_CTRL); |
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| 111 | rtems_bsp_delay(1000); |
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| 112 | |
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| 113 | if (GT64260TWSIintFlag()) { |
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| 114 | /* Check for completion of START sequence */ |
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| 115 | for (loop = 0; loop<MAX_LOOP; loop++ ) { |
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| 116 | /* if (start condition transmitted) || |
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| 117 | * (repeated start condition transmitted ) |
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| 118 | */ |
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| 119 | if (((status= inl( TWSI_STATUS)) == 8) || (status == 0x10)) { |
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| 120 | #if TWSI_DEBUG |
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| 121 | printk(")"); |
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| 122 | #endif |
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| 123 | return(0); |
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| 124 | } |
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| 125 | rtems_bsp_delay(1000); |
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| 126 | } |
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| 127 | } |
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| 128 | /* if loop ends or intFlag ==0 */ |
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| 129 | GT64260TWSIstop(); |
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| 130 | return(-1); |
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| 131 | } |
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| 132 | |
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[46a6fa91] | 133 | int GT64260TWSIread(unsigned char * pData, int lastByte) |
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[7be6ad9] | 134 | { |
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| 135 | unsigned int loop; |
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| 136 | |
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| 137 | #if TWSI_DEBUG |
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| 138 | printk("GT64260TWSIread("); |
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| 139 | #endif |
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| 140 | /* Clear INTFLG and set ACK and ENABLE bits */ |
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| 141 | outl((TWSI_ACK | TWSI_TWSIEN), TWSI_CTRL); |
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| 142 | rtems_bsp_delay(1000); |
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| 143 | |
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| 144 | if (GT64260TWSIintFlag()) { |
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| 145 | for (loop = 0; loop< MAX_LOOP; loop++) { |
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| 146 | /* if Master received read data, acknowledge transmitted */ |
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| 147 | if ( (inl( TWSI_STATUS) == 0x50)) { |
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| 148 | *pData = (unsigned char) inl( TWSI_DATA); |
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| 149 | rtems_bsp_delay(1500); |
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| 150 | |
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| 151 | /* Clear INTFLAG and set Enable bit only */ |
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| 152 | if (lastByte) outl(TWSI_TWSIEN, TWSI_CTRL); |
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| 153 | rtems_bsp_delay(1500); |
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| 154 | #if TWSI_DEBUG |
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| 155 | printk(")\n"); |
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| 156 | #endif |
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| 157 | return(0); |
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| 158 | } |
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| 159 | rtems_bsp_delay(1000); |
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| 160 | } /* end for */ |
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| 161 | } |
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| 162 | /* if loop ends or intFlag ==0 */ |
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| 163 | GT64260TWSIstop(); |
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| 164 | return(-1); |
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| 165 | } |
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| 166 | |
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| 167 | /* do a TWSI write cycle on the TWSI bus*/ |
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| 168 | int GT64260TWSIwrite(unsigned char Data) |
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| 169 | { |
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| 170 | unsigned int loop; |
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| 171 | unsigned int status; |
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| 172 | |
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| 173 | #if TWSI_DEBUG |
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| 174 | printk("GT64260TWSIwrite("); |
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| 175 | #endif |
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| 176 | /* Write data into the TWSI data register */ |
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| 177 | outl(((unsigned int) Data), TWSI_DATA); |
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| 178 | rtems_bsp_delay(1000); |
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| 179 | |
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| 180 | /* Clear INTFLG in the control register to drive data onto TWSI bus */ |
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| 181 | outl(0, TWSI_CTRL); |
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| 182 | rtems_bsp_delay(1000); |
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| 183 | |
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| 184 | if (GT64260TWSIintFlag() ) { |
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| 185 | for (loop = 0; loop< MAX_LOOP; loop++) { |
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| 186 | rtems_bsp_delay(1000); |
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| 187 | /* if address + write bit transmitted, acknowledge not received */ |
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| 188 | if ( (status = inl( TWSI_STATUS)) == 0x20) { |
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| 189 | /* No device responding, generate STOP and return -1 */ |
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| 190 | printk("no device responding\n"); |
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| 191 | GT64260TWSIstop(); |
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| 192 | return(-1); |
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| 193 | } |
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| 194 | /* if (address + write bit transmitted, acknowledge received) |
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| 195 | * (Master transmmitted data byte, acknowledge received) |
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| 196 | * (address + read bit transmitted, acknowledge received) |
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| 197 | */ |
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| 198 | if ((status == 0x18)||(status == 0x28)||(status == 0x40)) { |
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| 199 | #if TWSI_DEBUG |
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| 200 | printk(")\n"); |
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| 201 | #endif |
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| 202 | return(0); |
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| 203 | } |
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| 204 | rtems_bsp_delay(1000); |
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| 205 | } /* end for */ |
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| 206 | } |
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| 207 | printk("No correct status, timeout\n"); |
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| 208 | GT64260TWSIstop(); |
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| 209 | return(-1); |
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| 210 | } |
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