1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
|
#include <common.h>
#include <mpc8xx.h>
#include <malloc.h>
#include <galileo/gt64260R.h>
#include <galileo/core.h>
#define MAX_I2C_RETRYS 10
#define I2C_DELAY 1000 /* Should be at least the # of MHz of Tclk */
#undef DEBUG_I2C
#ifdef DEBUG_I2C
#define DP(x) x
#else
#define DP(x)
#endif
/* Assuming that there is only one master on the bus (us) */
static void
i2c_init(int speed, int slaveaddr)
{
unsigned int n, m, freq, margin, power;
unsigned int actualn = 0, actualm = 0;
unsigned int control, status;
unsigned int minmargin = 0xffffffff;
unsigned int tclk = 125000000;
DP(puts("i2c_init\n"));
for (n = 0 ; n < 8 ; n++) {
for (m = 0 ; m < 16 ; m++) {
power = 2 << n; /* power = 2^(n+1) */
freq = tclk / (10 * (m + 1) * power);
if (speed > freq)
margin = speed - freq;
else
margin = freq - speed;
if (margin < minmargin) {
minmargin = margin;
actualn = n;
actualm = m;
}
}
}
DP(puts("setup i2c bus\n"));
/* Setup bus */
GT_REG_WRITE(I2C_SOFT_RESET, 0);
DP(puts("udelay...\n"));
udelay(I2C_DELAY);
DP(puts("set baudrate\n"));
GT_REG_WRITE(I2C_STATUS_BAUDE_RATE, (actualm << 3) | actualn);
GT_REG_WRITE(I2C_CONTROL, (0x1 << 2) | (0x1 << 6));
udelay(I2C_DELAY * 10);
DP(puts("read control, baudrate\n"));
GT_REG_READ(I2C_STATUS_BAUDE_RATE, &status);
GT_REG_READ(I2C_CONTROL, &control);
}
static uchar
i2c_start(void)
{
unsigned int control, status;
int count = 0;
DP(puts("i2c_start\n"));
/* Set the start bit */
GT_REG_READ(I2C_CONTROL, &control);
control |= (0x1 << 5);
GT_REG_WRITE(I2C_CONTROL, control);
GT_REG_READ(I2C_STATUS_BAUDE_RATE, &status);
count = 0;
while ((status & 0xff) != 0x08) {
udelay(I2C_DELAY);
if (count > 20) {
GT_REG_WRITE(I2C_CONTROL, (0x1 << 4)); /*stop*/
return status;
}
GT_REG_READ(I2C_STATUS_BAUDE_RATE, &status);
count++;
}
return 0;
}
static uchar
i2c_select_device(uchar dev_addr, uchar read, int ten_bit)
{
unsigned int status, data, bits = 7;
int count = 0;
DP(puts("i2c_select_device\n"));
/* Output slave address */
if (ten_bit)
bits = 10;
data = (dev_addr << 1);
/* set the read bit */
data |= read;
GT_REG_WRITE(I2C_DATA, data);
/* assert the address */
RESET_REG_BITS(I2C_CONTROL, BIT3);
udelay(I2C_DELAY);
GT_REG_READ(I2C_STATUS_BAUDE_RATE, &status);
count = 0;
while (((status & 0xff) != 0x40) && ((status & 0xff) != 0x18)) {
udelay(I2C_DELAY);
if (count > 20) {
GT_REG_WRITE(I2C_CONTROL, (0x1 << 4)); /*stop*/
return status;
}
GT_REG_READ(I2C_STATUS_BAUDE_RATE, &status);
count++;
}
if (bits == 10) {
printf("10 bit I2C addressing not yet implemented\n");
return 0xff;
}
return 0;
}
static uchar
i2c_get_data(uchar *return_data, int len) {
unsigned int data, status = 0;
int count = 0;
DP(puts("i2c_get_data\n"));
while (len) {
/* Get and return the data */
RESET_REG_BITS(I2C_CONTROL, (0x1 << 3));
udelay(I2C_DELAY * 5);
GT_REG_READ(I2C_STATUS_BAUDE_RATE, &status);
count++;
while ((status & 0xff) != 0x50) {
udelay(I2C_DELAY);
if (count > 2) {
GT_REG_WRITE(I2C_CONTROL, (0x1 << 4)); /*stop*/
return 0;
}
GT_REG_READ(I2C_STATUS_BAUDE_RATE, &status);
count++;
}
GT_REG_READ(I2C_DATA, &data);
len--;
*return_data = (uchar)data;
return_data++;
}
RESET_REG_BITS(I2C_CONTROL, BIT2|BIT3);
while ((status & 0xff) != 0x58) {
udelay(I2C_DELAY);
if (count > 200) {
GT_REG_WRITE(I2C_CONTROL, (0x1 << 4)); /*stop*/
return status;
}
GT_REG_READ(I2C_STATUS_BAUDE_RATE, &status);
count++;
}
GT_REG_WRITE(I2C_CONTROL, (0x1 << 4)); /* stop */
return 0;
}
static uchar
i2c_write_data(unsigned int data, int len)
{
unsigned int status;
int count = 0;
DP(puts("i2c_write_data\n"));
if (len > 4)
return -1;
while (len) {
/* Set and assert the data */
GT_REG_WRITE(I2C_DATA, (unsigned int)data);
RESET_REG_BITS(I2C_CONTROL, (0x1 << 3));
udelay(I2C_DELAY);
GT_REG_READ(I2C_STATUS_BAUDE_RATE, &status);
count++;
while ((status & 0xff) != 0x28) {
udelay(I2C_DELAY);
if (count > 20) {
GT_REG_WRITE(I2C_CONTROL, (0x1 << 4)); /*stop*/
return status;
}
GT_REG_READ(I2C_STATUS_BAUDE_RATE, &status);
count++;
}
len--;
}
GT_REG_WRITE(I2C_CONTROL, (0x1 << 3) | (0x1 << 4));
GT_REG_WRITE(I2C_CONTROL, (0x1 << 4));
udelay(I2C_DELAY * 10);
return 0;
}
static uchar
i2c_set_dev_offset(uchar dev_addr, unsigned int offset, int ten_bit)
{
uchar status;
DP(puts("i2c_set_dev_offset\n"));
status = i2c_select_device(dev_addr, 0, ten_bit);
if (status) {
#ifdef DEBUG_I2C
printf("Failed to select device setting offset: 0x%02x\n",
status);
#endif
return status;
}
status = i2c_write_data(offset, 1);
if (status) {
#ifdef DEBUG_I2C
printf("Failed to write data: 0x%02x\n", status);
#endif
return status;
}
return 0;
}
uchar
i2c_read(uchar dev_addr, unsigned int offset, int len, uchar *data,
int ten_bit)
{
uchar status = 0;
unsigned int i2cfreq = 400000;
DP(puts("i2c_read\n"));
i2c_init(i2cfreq, 0);
status = i2c_start();
if (status) {
#ifdef DEBUG_I2C
printf("Transaction start failed: 0x%02x\n", status);
#endif
return status;
}
status = i2c_set_dev_offset(dev_addr, 0, 0);
if (status) {
#ifdef DEBUG_I2C
printf("Failed to set offset: 0x%02x\n", status);
#endif
return status;
}
i2c_init(i2cfreq, 0);
status = i2c_start();
if (status) {
#ifdef DEBUG_I2C
printf("Transaction restart failed: 0x%02x\n", status);
#endif
return status;
}
status = i2c_select_device(dev_addr, 1, ten_bit);
if (status) {
#ifdef DEBUG_I2C
printf("Address not acknowledged: 0x%02x\n", status);
#endif
return status;
}
status = i2c_get_data(data, len);
if (status) {
#ifdef DEBUG_I2C
printf("Data not received: 0x%02x\n", status);
#endif
return status;
}
return 0;
}
|
