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
|
/*
* i2c.c - driver for Blackfin on-chip TWI/I2C
*
* Copyright (c) 2006-2008 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <common.h>
#include <i2c.h>
#include <asm/blackfin.h>
#include <asm/mach-common/bits/twi.h>
#ifdef DEBUG
# define dmemset(s, c, n) memset(s, c, n)
#else
# define dmemset(s, c, n)
#endif
#define debugi(fmt, args...) \
debug( \
"MSTAT:0x%03x FSTAT:0x%x ISTAT:0x%02x\t" \
"%-20s:%-3i: " fmt "\n", \
bfin_read_TWI_MASTER_STAT(), bfin_read_TWI_FIFO_STAT(), bfin_read_TWI_INT_STAT(), \
__func__, __LINE__, ## args)
#ifdef TWI0_CLKDIV
#define bfin_write_TWI_CLKDIV(val) bfin_write_TWI0_CLKDIV(val)
#define bfin_write_TWI_CONTROL(val) bfin_write_TWI0_CONTROL(val)
#define bfin_read_TWI_CONTROL(val) bfin_read_TWI0_CONTROL(val)
#define bfin_write_TWI_MASTER_ADDR(val) bfin_write_TWI0_MASTER_ADDR(val)
#define bfin_write_TWI_XMT_DATA8(val) bfin_write_TWI0_XMT_DATA8(val)
#define bfin_read_TWI_RCV_DATA8() bfin_read_TWI0_RCV_DATA8()
#define bfin_read_TWI_INT_STAT() bfin_read_TWI0_INT_STAT()
#define bfin_write_TWI_INT_STAT(val) bfin_write_TWI0_INT_STAT(val)
#define bfin_read_TWI_MASTER_STAT() bfin_read_TWI0_MASTER_STAT()
#define bfin_write_TWI_MASTER_STAT(val) bfin_write_TWI0_MASTER_STAT(val)
#define bfin_read_TWI_MASTER_CTL() bfin_read_TWI0_MASTER_CTL()
#define bfin_write_TWI_MASTER_CTL(val) bfin_write_TWI0_MASTER_CTL(val)
#define bfin_write_TWI_INT_MASK(val) bfin_write_TWI0_INT_MASK(val)
#define bfin_write_TWI_FIFO_CTL(val) bfin_write_TWI0_FIFO_CTL(val)
#endif
#ifdef CONFIG_TWICLK_KHZ
# error do not define CONFIG_TWICLK_KHZ ... use CONFIG_SYS_I2C_SPEED
#endif
#if CONFIG_SYS_I2C_SPEED > 400000
# error The Blackfin I2C hardware can only operate at 400KHz max
#endif
/* All transfers are described by this data structure */
struct i2c_msg {
u8 flags;
#define I2C_M_COMBO 0x4
#define I2C_M_STOP 0x2
#define I2C_M_READ 0x1
int len; /* msg length */
u8 *buf; /* pointer to msg data */
int alen; /* addr length */
u8 *abuf; /* addr buffer */
};
/**
* wait_for_completion - manage the actual i2c transfer
* @msg: the i2c msg
*/
static int wait_for_completion(struct i2c_msg *msg)
{
uint16_t int_stat;
while (!ctrlc()) {
int_stat = bfin_read_TWI_INT_STAT();
if (int_stat & XMTSERV) {
debugi("processing XMTSERV");
bfin_write_TWI_INT_STAT(XMTSERV);
SSYNC();
if (msg->alen) {
bfin_write_TWI_XMT_DATA8(*(msg->abuf++));
--msg->alen;
} else if (!(msg->flags & I2C_M_COMBO) && msg->len) {
bfin_write_TWI_XMT_DATA8(*(msg->buf++));
--msg->len;
} else {
bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() |
(msg->flags & I2C_M_COMBO ? RSTART | MDIR : STOP));
SSYNC();
}
}
if (int_stat & RCVSERV) {
debugi("processing RCVSERV");
bfin_write_TWI_INT_STAT(RCVSERV);
SSYNC();
if (msg->len) {
*(msg->buf++) = bfin_read_TWI_RCV_DATA8();
--msg->len;
} else if (msg->flags & I2C_M_STOP) {
bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() | STOP);
SSYNC();
}
}
if (int_stat & MERR) {
debugi("processing MERR");
bfin_write_TWI_INT_STAT(MERR);
SSYNC();
break;
}
if (int_stat & MCOMP) {
debugi("processing MCOMP");
bfin_write_TWI_INT_STAT(MCOMP);
SSYNC();
if (msg->flags & I2C_M_COMBO && msg->len) {
bfin_write_TWI_MASTER_CTL((bfin_read_TWI_MASTER_CTL() & ~RSTART) |
(min(msg->len, 0xff) << 6) | MEN | MDIR);
SSYNC();
} else
break;
}
}
return msg->len;
}
/**
* i2c_transfer - setup an i2c transfer
* @return: 0 if things worked, non-0 if things failed
*
* Here we just get the i2c stuff all prepped and ready, and then tail off
* into wait_for_completion() for all the bits to go.
*/
static int i2c_transfer(uchar chip, uint addr, int alen, uchar *buffer, int len, u8 flags)
{
uchar addr_buffer[] = {
(addr >> 0),
(addr >> 8),
(addr >> 16),
};
struct i2c_msg msg = {
.flags = flags | (len >= 0xff ? I2C_M_STOP : 0),
.buf = buffer,
.len = len,
.abuf = addr_buffer,
.alen = alen,
};
int ret;
dmemset(buffer, 0xff, len);
debugi("chip=0x%x addr=0x%02x alen=%i buf[0]=0x%02x len=%i flags=0x%02x[%s] ",
chip, addr, alen, buffer[0], len, flags, (flags & I2C_M_READ ? "rd" : "wr"));
/* wait for things to settle */
while (bfin_read_TWI_MASTER_STAT() & BUSBUSY)
if (ctrlc())
return 1;
/* Set Transmit device address */
bfin_write_TWI_MASTER_ADDR(chip);
/* Clear the FIFO before starting things */
bfin_write_TWI_FIFO_CTL(XMTFLUSH | RCVFLUSH);
SSYNC();
bfin_write_TWI_FIFO_CTL(0);
SSYNC();
/* prime the pump */
if (msg.alen) {
len = msg.alen;
debugi("first byte=0x%02x", *msg.abuf);
bfin_write_TWI_XMT_DATA8(*(msg.abuf++));
--msg.alen;
} else if (!(msg.flags & I2C_M_READ) && msg.len) {
debugi("first byte=0x%02x", *msg.buf);
bfin_write_TWI_XMT_DATA8(*(msg.buf++));
--msg.len;
}
/* clear int stat */
bfin_write_TWI_MASTER_STAT(-1);
bfin_write_TWI_INT_STAT(-1);
bfin_write_TWI_INT_MASK(0);
SSYNC();
/* Master enable */
bfin_write_TWI_MASTER_CTL(
(bfin_read_TWI_MASTER_CTL() & FAST) |
(min(len, 0xff) << 6) | MEN |
((msg.flags & I2C_M_READ) ? MDIR : 0)
);
SSYNC();
debugi("CTL=0x%04x", bfin_read_TWI_MASTER_CTL());
/* process the rest */
ret = wait_for_completion(&msg);
debugi("ret=%d", ret);
if (ret) {
bfin_write_TWI_MASTER_CTL(bfin_read_TWI_MASTER_CTL() & ~MEN);
bfin_write_TWI_CONTROL(bfin_read_TWI_CONTROL() & ~TWI_ENA);
SSYNC();
bfin_write_TWI_CONTROL(bfin_read_TWI_CONTROL() | TWI_ENA);
SSYNC();
}
return ret;
}
/*
* i2c_init - initialize the i2c bus
* @speed: bus speed (in HZ)
* @slaveaddr: address of device in slave mode (0 - not slave)
*
* Slave mode isn't actually implemented. It'll stay that way until
* we get a real request for it.
*/
void i2c_init(int speed, int slaveaddr)
{
uint8_t prescale = ((get_sclk() / 1024 / 1024 + 5) / 10) & 0x7F;
/* Set TWI internal clock as 10MHz */
bfin_write_TWI_CONTROL(prescale);
/* Set TWI interface clock as specified */
bfin_write_TWI_CLKDIV(
((5 * 1024 / (speed / 1000)) << 8) |
((5 * 1024 / (speed / 1000)) & 0xFF)
);
/* Don't turn it on */
bfin_write_TWI_MASTER_CTL(speed > 100000 ? FAST : 0);
/* But enable it */
bfin_write_TWI_CONTROL(TWI_ENA | prescale);
SSYNC();
debugi("CONTROL:0x%04x CLKDIV:0x%04x",
bfin_read_TWI_CONTROL(), bfin_read_TWI_CLKDIV());
#if CONFIG_SYS_I2C_SLAVE
# error I2C slave support not tested/supported
/* If they want us as a slave, do it */
if (slaveaddr) {
bfin_write_TWI_SLAVE_ADDR(slaveaddr);
bfin_write_TWI_SLAVE_CTL(SEN);
}
#endif
}
/**
* i2c_probe - test if a chip exists at a given i2c address
* @chip: i2c chip addr to search for
* @return: 0 if found, non-0 if not found
*/
int i2c_probe(uchar chip)
{
u8 byte;
return i2c_read(chip, 0, 0, &byte, 1);
}
/**
* i2c_read - read data from an i2c device
* @chip: i2c chip addr
* @addr: memory (register) address in the chip
* @alen: byte size of address
* @buffer: buffer to store data read from chip
* @len: how many bytes to read
* @return: 0 on success, non-0 on failure
*/
int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
return i2c_transfer(chip, addr, alen, buffer, len, (alen ? I2C_M_COMBO : I2C_M_READ));
}
/**
* i2c_write - write data to an i2c device
* @chip: i2c chip addr
* @addr: memory (register) address in the chip
* @alen: byte size of address
* @buffer: buffer to store data read from chip
* @len: how many bytes to write
* @return: 0 on success, non-0 on failure
*/
int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
{
return i2c_transfer(chip, addr, alen, buffer, len, 0);
}
|
