summaryrefslogtreecommitdiff
path: root/drivers/i2c/mxc_i2c.c
blob: 01a64081d7e8e342eddc4c5e9d9b3c15708aede3 (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
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
/*
 * i2c driver for Freescale i.MX series
 *
 * (c) 2007 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
 * (c) 2011 Marek Vasut <marek.vasut@gmail.com>
 *
 * Based on i2c-imx.c from linux kernel:
 *  Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de>
 *  Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de>
 *  Copyright (C) 2007 RightHand Technologies, Inc.
 *  Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
 *
 *
 * 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>
#include <asm/arch/clock.h>
#include <asm/arch/imx-regs.h>
#include <asm/errno.h>
#include <asm/io.h>
#include <i2c.h>
#include <watchdog.h>

struct mxc_i2c_regs {
	uint32_t	iadr;
	uint32_t	ifdr;
	uint32_t	i2cr;
	uint32_t	i2sr;
	uint32_t	i2dr;
};

#define I2CR_IEN	(1 << 7)
#define I2CR_IIEN	(1 << 6)
#define I2CR_MSTA	(1 << 5)
#define I2CR_MTX	(1 << 4)
#define I2CR_TX_NO_AK	(1 << 3)
#define I2CR_RSTA	(1 << 2)

#define I2SR_ICF	(1 << 7)
#define I2SR_IBB	(1 << 5)
#define I2SR_IIF	(1 << 1)
#define I2SR_RX_NO_AK	(1 << 0)

#ifdef CONFIG_SYS_I2C_BASE
#define I2C_BASE	CONFIG_SYS_I2C_BASE
#else
#error "define CONFIG_SYS_I2C_BASE to use the mxc_i2c driver"
#endif

static u16 i2c_clk_div[50][2] = {
	{ 22,	0x20 }, { 24,	0x21 }, { 26,	0x22 }, { 28,	0x23 },
	{ 30,	0x00 }, { 32,	0x24 }, { 36,	0x25 }, { 40,	0x26 },
	{ 42,	0x03 }, { 44,	0x27 }, { 48,	0x28 }, { 52,	0x05 },
	{ 56,	0x29 }, { 60,	0x06 }, { 64,	0x2A }, { 72,	0x2B },
	{ 80,	0x2C }, { 88,	0x09 }, { 96,	0x2D }, { 104,	0x0A },
	{ 112,	0x2E }, { 128,	0x2F }, { 144,	0x0C }, { 160,	0x30 },
	{ 192,	0x31 }, { 224,	0x32 }, { 240,	0x0F }, { 256,	0x33 },
	{ 288,	0x10 }, { 320,	0x34 }, { 384,	0x35 }, { 448,	0x36 },
	{ 480,	0x13 }, { 512,	0x37 }, { 576,	0x14 }, { 640,	0x38 },
	{ 768,	0x39 }, { 896,	0x3A }, { 960,	0x17 }, { 1024,	0x3B },
	{ 1152,	0x18 }, { 1280,	0x3C }, { 1536,	0x3D }, { 1792,	0x3E },
	{ 1920,	0x1B }, { 2048,	0x3F }, { 2304,	0x1C }, { 2560,	0x1D },
	{ 3072,	0x1E }, { 3840,	0x1F }
};

/*
 * Calculate and set proper clock divider
 */
static uint8_t i2c_imx_get_clk(unsigned int rate)
{
	unsigned int i2c_clk_rate;
	unsigned int div;
	u8 clk_div;

#if defined(CONFIG_MX31)
	struct clock_control_regs *sc_regs =
		(struct clock_control_regs *)CCM_BASE;

	/* start the required I2C clock */
	writel(readl(&sc_regs->cgr0) | (3 << CONFIG_SYS_I2C_CLK_OFFSET),
		&sc_regs->cgr0);
#endif

	/* Divider value calculation */
	i2c_clk_rate = mxc_get_clock(MXC_IPG_PERCLK);
	div = (i2c_clk_rate + rate - 1) / rate;
	if (div < i2c_clk_div[0][0])
		clk_div = 0;
	else if (div > i2c_clk_div[ARRAY_SIZE(i2c_clk_div) - 1][0])
		clk_div = ARRAY_SIZE(i2c_clk_div) - 1;
	else
		for (clk_div = 0; i2c_clk_div[clk_div][0] < div; clk_div++)
			;

	/* Store divider value */
	return clk_div;
}

/*
 * Reset I2C Controller
 */
void i2c_reset(void)
{
	struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;

	writeb(0, &i2c_regs->i2cr);	/* Reset module */
	writeb(0, &i2c_regs->i2sr);
}

/*
 * Init I2C Bus
 */
void i2c_init(int speed, int unused)
{
	struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
	u8 clk_idx = i2c_imx_get_clk(speed);
	u8 idx = i2c_clk_div[clk_idx][1];

	/* Store divider value */
	writeb(idx, &i2c_regs->ifdr);

	i2c_reset();
}

/*
 * Set I2C Speed
 */
int i2c_set_bus_speed(unsigned int speed)
{
	i2c_init(speed, 0);
	return 0;
}

/*
 * Get I2C Speed
 */
unsigned int i2c_get_bus_speed(void)
{
	struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
	u8 clk_idx = readb(&i2c_regs->ifdr);
	u8 clk_div;

	for (clk_div = 0; i2c_clk_div[clk_div][1] != clk_idx; clk_div++)
		;

	return mxc_get_clock(MXC_IPG_PERCLK) / i2c_clk_div[clk_div][0];
}

#define ST_BUS_IDLE (0 | (I2SR_IBB << 8))
#define ST_BUS_BUSY (I2SR_IBB | (I2SR_IBB << 8))
#define ST_IIF (I2SR_IIF | (I2SR_IIF << 8))

static int wait_for_sr_state(struct mxc_i2c_regs *i2c_regs, unsigned state)
{
	unsigned sr;
	ulong elapsed;
	ulong start_time = get_timer(0);
	for (;;) {
		sr = readb(&i2c_regs->i2sr);
		if ((sr & (state >> 8)) == (unsigned char)state)
			return sr;
		WATCHDOG_RESET();
		elapsed = get_timer(start_time);
		if (elapsed > (CONFIG_SYS_HZ / 10))	/* .1 seconds */
			break;
	}
	printf("%s: failed sr=%x cr=%x state=%x\n", __func__,
			sr, readb(&i2c_regs->i2cr), state);
	return -ETIMEDOUT;
}

static int tx_byte(struct mxc_i2c_regs *i2c_regs, u8 byte)
{
	int ret;

	writeb(0, &i2c_regs->i2sr);
	writeb(byte, &i2c_regs->i2dr);
	ret = wait_for_sr_state(i2c_regs, ST_IIF);
	if (ret < 0)
		return ret;
	ret = readb(&i2c_regs->i2sr);
	if (ret & I2SR_RX_NO_AK)
		return -ENODEV;
	return 0;
}

/*
 * Start the controller
 */
int i2c_imx_start(void)
{
	struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
	unsigned int temp = 0;
	int result;

	/* Enable I2C controller */
	writeb(0, &i2c_regs->i2sr);
	writeb(I2CR_IEN, &i2c_regs->i2cr);

	/* Wait controller to be stable */
	udelay(50);

	/* Start I2C transaction */
	temp = readb(&i2c_regs->i2cr);
	temp |= I2CR_MSTA;
	writeb(temp, &i2c_regs->i2cr);

	result = wait_for_sr_state(i2c_regs, ST_BUS_BUSY);
	if (result < 0)
		return result;

	temp |= I2CR_MTX | I2CR_TX_NO_AK;
	writeb(temp, &i2c_regs->i2cr);

	return 0;
}

/*
 * Stop the controller
 */
void i2c_imx_stop(void)
{
	int ret;
	struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
	unsigned int temp = 0;

	/* Stop I2C transaction */
	temp = readb(&i2c_regs->i2cr);
	temp &= ~(I2CR_MSTA | I2CR_MTX);
	writeb(temp, &i2c_regs->i2cr);

	ret = wait_for_sr_state(i2c_regs, ST_BUS_IDLE);
	if (ret < 0)
		printf("%s:trigger stop failed\n", __func__);
	/* Disable I2C controller */
	writeb(0, &i2c_regs->i2cr);
}

/*
 * Send start signal, chip address and
 * write register address
 */
static int i2c_init_transfer(struct mxc_i2c_regs *i2c_regs,
		uchar chip, uint addr, int alen)
{
	int ret = i2c_imx_start();
	if (ret)
		goto exit;

	/* write slave address */
	ret = tx_byte(i2c_regs, chip << 1);
	if (ret < 0)
		goto exit;

	while (alen--) {
		ret = tx_byte(i2c_regs, (addr >> (alen * 8)) & 0xff);
		if (ret < 0)
			goto exit;
	}
	return 0;
exit:
	i2c_imx_stop();
	return ret;
}

/*
 * Read data from I2C device
 */
int i2c_read(uchar chip, uint addr, int alen, uchar *buf, int len)
{
	struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
	int ret;
	unsigned int temp;
	int i;

	ret = i2c_init_transfer(i2c_regs, chip, addr, alen);
	if (ret < 0)
		return ret;

	temp = readb(&i2c_regs->i2cr);
	temp |= I2CR_RSTA;
	writeb(temp, &i2c_regs->i2cr);

	ret = tx_byte(i2c_regs, (chip << 1) | 1);
	if (ret < 0) {
		i2c_imx_stop();
		return ret;
	}

	/* setup bus to read data */
	temp = readb(&i2c_regs->i2cr);
	temp &= ~(I2CR_MTX | I2CR_TX_NO_AK);
	if (len == 1)
		temp |= I2CR_TX_NO_AK;
	writeb(temp, &i2c_regs->i2cr);
	writeb(0, &i2c_regs->i2sr);
	readb(&i2c_regs->i2dr);		/* dummy read to clear ICF */

	/* read data */
	for (i = 0; i < len; i++) {
		ret = wait_for_sr_state(i2c_regs, ST_IIF);
		if (ret < 0) {
			i2c_imx_stop();
			return ret;
		}

		/*
		 * It must generate STOP before read I2DR to prevent
		 * controller from generating another clock cycle
		 */
		if (i == (len - 1)) {
			temp = readb(&i2c_regs->i2cr);
			temp &= ~(I2CR_MSTA | I2CR_MTX);
			writeb(temp, &i2c_regs->i2cr);
			wait_for_sr_state(i2c_regs, ST_BUS_IDLE);
		} else if (i == (len - 2)) {
			temp = readb(&i2c_regs->i2cr);
			temp |= I2CR_TX_NO_AK;
			writeb(temp, &i2c_regs->i2cr);
		}
		writeb(0, &i2c_regs->i2sr);
		buf[i] = readb(&i2c_regs->i2dr);
	}

	i2c_imx_stop();

	return 0;
}

/*
 * Write data to I2C device
 */
int i2c_write(uchar chip, uint addr, int alen, uchar *buf, int len)
{
	struct mxc_i2c_regs *i2c_regs = (struct mxc_i2c_regs *)I2C_BASE;
	int ret;
	int i;

	ret = i2c_init_transfer(i2c_regs, chip, addr, alen);
	if (ret < 0)
		return ret;

	for (i = 0; i < len; i++) {
		ret = tx_byte(i2c_regs, buf[i]);
		if (ret < 0)
			break;
	}

	i2c_imx_stop();

	return ret;
}

/*
 * Test if a chip at a given address responds (probe the chip)
 */
int i2c_probe(uchar chip)
{
	return i2c_write(chip, 0, 0, NULL, 0);
}