aboutsummaryrefslogtreecommitdiff
path: root/cpu/mpc5xxx/i2c.c
blob: 640d14022fcc84bd763ed68f00e869b4a493fcf9 (plain)
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
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
/*
 * (C) Copyright 2003
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * See file CREDITS for list of people who contributed to this
 * project.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 */

#include <common.h>

#ifdef CONFIG_HARD_I2C

#include <mpc5xxx.h>
#include <i2c.h>

#ifdef CFG_I2C_MODULE
#define I2C_BASE	MPC5XXX_I2C2
#else
#define I2C_BASE	MPC5XXX_I2C1
#endif

#define I2C_TIMEOUT	100
#define I2C_RETRIES	3

static int  mpc_reg_in    (volatile u32 *reg);
static void mpc_reg_out   (volatile u32 *reg, int val, int mask);
static int  wait_for_bb   (void);
static int  wait_for_pin  (int *status);
static int  do_address    (uchar chip, char rdwr_flag);
static int  send_bytes    (uchar chip, char *buf, int len);
static int  receive_bytes (uchar chip, char *buf, int len);

static int mpc_reg_in(volatile u32 *reg)
{
	return *reg >> 24;
	__asm__ __volatile__ ("eieio");
}

static void mpc_reg_out(volatile u32 *reg, int val, int mask)
{
	int tmp;

	if (!mask) {
		*reg = val << 24;
	} else {
		tmp = mpc_reg_in(reg);
		*reg = ((tmp & ~mask) | (val & mask)) << 24;
	}
	__asm__ __volatile__ ("eieio");

	return;
}

static int wait_for_bb(void)
{
	struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
	int                 timeout = I2C_TIMEOUT;
	int                 status;

	status = mpc_reg_in(&regs->msr);

	while (timeout-- && (status & I2C_BB)) {
#if 1
		volatile int temp;
		mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
		temp = mpc_reg_in(&regs->mdr);
		mpc_reg_out(&regs->mcr, 0, I2C_STA);
		mpc_reg_out(&regs->mcr, 0, 0);
		mpc_reg_out(&regs->mcr, I2C_EN, 0);
#endif
		udelay(1000);
		status = mpc_reg_in(&regs->msr);
	}

	return (status & I2C_BB);
}

static int wait_for_pin(int *status)
{
	struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
	int                 timeout = I2C_TIMEOUT;

	*status = mpc_reg_in(&regs->msr);

	while (timeout-- && !(*status & I2C_IF)) {
		udelay(1000);
		*status = mpc_reg_in(&regs->msr);
	}

	if (!(*status & I2C_IF)) {
		return -1;
	}

	mpc_reg_out(&regs->msr, 0, I2C_IF);

	return 0;
}

static int do_address(uchar chip, char rdwr_flag)
{
	struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
	int                 status;

	chip <<= 1;

	if (rdwr_flag) {
		chip |= 1;
	}

	mpc_reg_out(&regs->mcr, I2C_TX, I2C_TX);
	mpc_reg_out(&regs->mdr, chip, 0);

        if (wait_for_pin(&status)) {
                return -2;
        }

        if (status & I2C_RXAK) {
                return -3;
        }

	return 0;
}

static int send_bytes(uchar chip, char *buf, int len)
{
	struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
	int                 wrcount;
	int                 status;

	for (wrcount = 0; wrcount < len; ++wrcount) {

		mpc_reg_out(&regs->mdr, buf[wrcount], 0);

		if (wait_for_pin(&status)) {
			break;
		}

		if (status & I2C_RXAK) {
			break;
		}

	}

	return !(wrcount == len);
}

static int receive_bytes(uchar chip, char *buf, int len)
{
	struct mpc5xxx_i2c *regs    = (struct mpc5xxx_i2c *)I2C_BASE;
	int                 dummy   = 1;
	int                 rdcount = 0;
	int                 status;
	int                 i;

	mpc_reg_out(&regs->mcr, 0, I2C_TX);

	for (i = 0; i < len; ++i) {
		buf[rdcount] = mpc_reg_in(&regs->mdr);

		if (dummy) {
			dummy = 0;
		} else {
			rdcount++;
		}


		if (wait_for_pin(&status)) {
			return -4;
		}
	}

	mpc_reg_out(&regs->mcr, I2C_TXAK, I2C_TXAK);
	buf[rdcount++] = mpc_reg_in(&regs->mdr);

	if (wait_for_pin(&status)) {
		return -5;
	}

	mpc_reg_out(&regs->mcr, 0, I2C_TXAK);

	return 0;
}

/**************** I2C API ****************/

void i2c_init(int speed, int saddr)
{
	struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;

	mpc_reg_out(&regs->mcr, 0, 0);
	mpc_reg_out(&regs->madr, saddr << 1, 0);

	/* Set clock
	 */
	mpc_reg_out(&regs->mfdr, speed, 0);

	/* Enable module
	 */
	mpc_reg_out(&regs->mcr, I2C_EN, I2C_INIT_MASK);
	mpc_reg_out(&regs->msr, 0, I2C_IF);

	return;
}

int i2c_probe(uchar chip)
{
	struct mpc5xxx_i2c *regs = (struct mpc5xxx_i2c *)I2C_BASE;
	int                 i;

	for (i = 0; i < I2C_RETRIES; i++) {
		mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);

		if (! do_address(chip, 0)) {
			mpc_reg_out(&regs->mcr, 0, I2C_STA);
			break;
		}

		mpc_reg_out(&regs->mcr, 0, I2C_STA);
		udelay(500);
	}

	return (i == I2C_RETRIES);
}

int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
{
	uchar                xaddr[4];
	struct mpc5xxx_i2c * regs        = (struct mpc5xxx_i2c *)I2C_BASE;
	int                  ret         = -1;

	xaddr[0] = (addr >> 24) & 0xFF;
	xaddr[1] = (addr >> 16) & 0xFF;
	xaddr[2] = (addr >>  8) & 0xFF;
	xaddr[3] =  addr	& 0xFF;

	if (wait_for_bb()) {
		printf("i2c_read: bus is busy\n");
		goto Done;
	}

	mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
	if (do_address(chip, 0)) {
		printf("i2c_read: failed to address chip\n");
		goto Done;
	}

	if (send_bytes(chip, &xaddr[4-alen], alen)) {
		printf("i2c_read: send_bytes failed\n");
		goto Done;
	}

	mpc_reg_out(&regs->mcr, I2C_RSTA, I2C_RSTA);
	if (do_address(chip, 1)) {
		printf("i2c_read: failed to address chip\n");
		goto Done;
	}

	if (receive_bytes(chip, buf, len)) {
		printf("i2c_read: receive_bytes failed\n");
		goto Done;
	}

	ret = 0;
Done:
	mpc_reg_out(&regs->mcr, 0, I2C_STA);
	return ret;
}

int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
{
	uchar               xaddr[4];
	struct mpc5xxx_i2c *regs        = (struct mpc5xxx_i2c *)I2C_BASE;
	int                 ret         = -1;

	xaddr[0] = (addr >> 24) & 0xFF;
	xaddr[1] = (addr >> 16) & 0xFF;
	xaddr[2] = (addr >>  8) & 0xFF;
	xaddr[3] =  addr	& 0xFF;

        if (wait_for_bb()) {
		printf("i2c_write: bus is busy\n");
		goto Done;
	}

        mpc_reg_out(&regs->mcr, I2C_STA, I2C_STA);
        if (do_address(chip, 0)) {
		printf("i2c_write: failed to address chip\n");
		goto Done;
	}

	if (send_bytes(chip, &xaddr[4-alen], alen)) {
		printf("i2c_write: send_bytes failed\n");
		goto Done;
	}

	if (send_bytes(chip, buf, len)) {
		printf("i2c_write: send_bytes failed\n");
		goto Done;
	}

	ret = 0;
Done:
	mpc_reg_out(&regs->mcr, 0, I2C_STA);
	return ret;
}

uchar i2c_reg_read(uchar chip, uchar reg)
{
	char buf;

	i2c_read(chip, reg, 1, &buf, 1);

	return buf;
}

void i2c_reg_write(uchar chip, uchar reg, uchar val)
{
	i2c_write(chip, reg, 1, &val, 1);

	return;
}

#endif	/* CONFIG_HARD_I2C */