source: rtems/c/src/lib/libbsp/powerpc/mvme5500/GT64260/GT64260TWSI.c @ 5d2f5196

4.104.114.9
Last change on this file since 5d2f5196 was 5d2f5196, checked in by Ralf Corsepius <ralf.corsepius@…>, on Aug 20, 2008 at 11:32:46 AM

Add missing prototypes.

  • Property mode set to 100644
File size: 5.0 KB
Line 
1/* GT64260TWSI.c : Two-Wire Serial Interface (TWSI) support for the GT64260
2 *
3 * Copyright (c) 2004, Brookhaven National Laboratory and
4 *                 Shuchen Kate Feng <feng1@bnl.gov>
5 * All rights reserved.
6 *
7 * The license and distribution terms for this file may be
8 * found in the file LICENSE in this distribution.
9 *
10 * See section 24:TWSI interface of "the GT-64260B System Controller
11 * for powerPc Processors Data Sheet".
12 *
13 * For full TWSI protocol description look in Philips Semiconductor
14 * TWSI spec.
15 *
16 * We need it to read out I2C devices used for the MVME5500
17 * (eg. the memory SPD and VPD).
18 *
19 */
20#include <libcpu/spr.h>  /*registers.h included here for rtems_bsp_delay()*/
21#include <libcpu/io.h>
22#include <rtems/bspIo.h>            /* printk */
23
24#include "bsp/gtreg.h"
25#include "bsp/GT64260TWSI.h"
26
27#define MAX_LOOP 100
28
29#define TWSI_DEBUG 0
30
31int TWSI_initFlg = 0;   /* TWSI Initialization Flag */
32
33void GT64260TWSIinit(void)
34{
35
36  if ( !TWSI_initFlg) {
37#if TWSI_DEBUG
38     printk("GT64260TWSIinit(");
39#endif
40     outl( 0, TWSI_SFT_RST); /* soft reset */
41     rtems_bsp_delay(1000);
42
43     /* See 24.2.5 : Assume bus speed is 133MHZ
44      * Try to be close to the default frequency : 62.5KHZ
45      * value 0x2c: 69.27 KHz TWSI bus clock
46      */ 
47     outl(0x2c, TWSI_BAUDE_RATE);
48     rtems_bsp_delay(1000);
49
50     /* Set Acknowledge and enable TWSI in the Control register */
51     outl(0x44, TWSI_CTRL);
52     rtems_bsp_delay(4000);
53     TWSI_initFlg = 1;
54#if TWSI_DEBUG
55     printk(")\n");
56#endif
57  }     
58}
59
60/* return the interrupt flag */
61int GT64260TWSIintFlag(void) 
62{
63  unsigned int loop;
64
65  for (loop = 0; loop < MAX_LOOP; loop++ ) {
66    /* Return 1 if the interrupt flag is set */
67      if (inl(TWSI_CTRL) & TWSI_INTFLG) return(1);
68      rtems_bsp_delay(1000);
69  }
70  return(0);
71}
72
73int GT64260TWSIstop(void) 
74{
75
76#if TWSI_DEBUG
77  printk("GT64260TWSIstop(");
78#endif
79
80  outl((inl(TWSI_CTRL) | TWSI_STOP), TWSI_CTRL);
81  rtems_bsp_delay(1000);
82
83  /* Check if interrupt flag bit is set*/
84  if (GT64260TWSIintFlag()) {
85     outl((inl( TWSI_CTRL) & ~TWSI_INTFLG), TWSI_CTRL);
86     rtems_bsp_delay(1000);
87#if TWSI_DEBUG
88     printk(")\n");
89#endif
90     return(0);
91  }
92#if TWSI_DEBUG
93     printk("NoIntFlag\n");
94#endif
95  return(-1);
96}
97
98int GT64260TWSIstart(void)
99{
100  unsigned int loop;   
101  unsigned int status; 
102
103#if TWSI_DEBUG
104  printk("GT64260TWSIstart(");
105#endif
106  /* Initialize the TWSI interface */
107  GT64260TWSIinit();
108
109  /* set the start bit */
110  outl((TWSI_START | TWSI_TWSIEN), TWSI_CTRL);
111  rtems_bsp_delay(1000);
112
113  if (GT64260TWSIintFlag()) {
114     /* Check for completion of START sequence */
115     for (loop = 0; loop<MAX_LOOP; loop++ ) {
116         /* if (start condition transmitted) ||
117          *    (repeated start condition transmitted )
118          */
119         if (((status= inl( TWSI_STATUS)) == 8) || (status == 0x10)) {
120#if TWSI_DEBUG
121             printk(")");
122#endif
123             return(0);
124         }
125         rtems_bsp_delay(1000);
126     }
127  }
128  /* if loop ends or intFlag ==0 */
129  GT64260TWSIstop();
130  return(-1);
131}
132
133int GT64260TWSIread(unsigned char * pData, int lastByte) 
134{
135  unsigned int loop;           
136
137#if TWSI_DEBUG
138  printk("GT64260TWSIread(");
139#endif
140  /* Clear INTFLG and set ACK and ENABLE bits */
141  outl((TWSI_ACK | TWSI_TWSIEN), TWSI_CTRL);
142  rtems_bsp_delay(1000);
143
144  if (GT64260TWSIintFlag()) {
145     for (loop = 0; loop< MAX_LOOP; loop++) {
146       /* if Master received read data, acknowledge transmitted */
147       if ( (inl( TWSI_STATUS) == 0x50)) {
148           *pData = (unsigned char) inl( TWSI_DATA); 
149           rtems_bsp_delay(1500);
150
151           /* Clear INTFLAG and set Enable bit only */
152           if (lastByte) outl(TWSI_TWSIEN, TWSI_CTRL);
153           rtems_bsp_delay(1500);
154#if TWSI_DEBUG
155  printk(")\n");
156#endif
157           return(0);
158        }
159        rtems_bsp_delay(1000);
160     } /* end for */
161  }
162  /* if loop ends or intFlag ==0 */
163  GT64260TWSIstop();
164  return(-1);
165}
166
167/* do a TWSI write cycle on the TWSI bus*/
168int GT64260TWSIwrite(unsigned char Data) 
169{
170  unsigned int loop;           
171  unsigned int status; 
172
173#if TWSI_DEBUG
174  printk("GT64260TWSIwrite(");
175#endif
176  /* Write data into the TWSI data register */
177  outl(((unsigned int) Data), TWSI_DATA); 
178  rtems_bsp_delay(1000);
179
180  /* Clear INTFLG in the control register to drive data onto TWSI bus */
181  outl(0, TWSI_CTRL);
182  rtems_bsp_delay(1000);
183
184  if (GT64260TWSIintFlag() ) {
185     for (loop = 0; loop< MAX_LOOP; loop++) {
186         rtems_bsp_delay(1000);
187         /* if address + write bit transmitted, acknowledge not received */
188         if ( (status = inl( TWSI_STATUS)) == 0x20) {
189            /* No device responding, generate STOP and return -1 */
190           printk("no device responding\n");
191            GT64260TWSIstop();
192            return(-1);
193         }
194         /* if (address + write bit transmitted, acknowledge received)
195          *    (Master transmmitted data byte, acknowledge received)
196          *    (address + read bit transmitted, acknowledge received)
197          */
198         if ((status == 0x18)||(status == 0x28)||(status == 0x40)) {
199#if TWSI_DEBUG
200              printk(")\n");
201#endif
202              return(0);
203         }
204         rtems_bsp_delay(1000);
205     } /* end for */
206  }
207  printk("No correct status, timeout\n");
208  GT64260TWSIstop();
209  return(-1);
210}
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