aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-pasemi.c
blob: 837b8c1aa02a494ef92899c46ccaf67cb709f9c1 (plain) (blame)
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
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
/*
 * Copyright (C) 2006-2007 PA Semi, Inc
 *
 * SMBus host driver for PA Semi PWRficient
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * 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 <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/stddef.h>
#include <linux/sched.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/io.h>

static struct pci_driver pasemi_smb_driver;

struct pasemi_smbus {
	struct pci_dev		*dev;
	struct i2c_adapter	 adapter;
	unsigned long		 base;
	int			 size;
};

/* Register offsets */
#define REG_MTXFIFO	0x00
#define REG_MRXFIFO	0x04
#define REG_SMSTA	0x14
#define REG_CTL		0x1c

/* Register defs */
#define MTXFIFO_READ	0x00000400
#define MTXFIFO_STOP	0x00000200
#define MTXFIFO_START	0x00000100
#define MTXFIFO_DATA_M	0x000000ff

#define MRXFIFO_EMPTY	0x00000100
#define MRXFIFO_DATA_M	0x000000ff

#define SMSTA_XEN	0x08000000
#define SMSTA_MTN	0x00200000

#define CTL_MRR		0x00000400
#define CTL_MTR		0x00000200
#define CTL_CLK_M	0x000000ff

#define CLK_100K_DIV	84
#define CLK_400K_DIV	21

static inline void reg_write(struct pasemi_smbus *smbus, int reg, int val)
{
	dev_dbg(&smbus->dev->dev, "smbus write reg %lx val %08x\n",
		smbus->base + reg, val);
	outl(val, smbus->base + reg);
}

static inline int reg_read(struct pasemi_smbus *smbus, int reg)
{
	int ret;
	ret = inl(smbus->base + reg);
	dev_dbg(&smbus->dev->dev, "smbus read reg %lx val %08x\n",
		smbus->base + reg, ret);
	return ret;
}

#define TXFIFO_WR(smbus, reg)	reg_write((smbus), REG_MTXFIFO, (reg))
#define RXFIFO_RD(smbus)	reg_read((smbus), REG_MRXFIFO)

static void pasemi_smb_clear(struct pasemi_smbus *smbus)
{
	unsigned int status;

	status = reg_read(smbus, REG_SMSTA);
	reg_write(smbus, REG_SMSTA, status);
}

static int pasemi_smb_waitready(struct pasemi_smbus *smbus)
{
	int timeout = 10;
	unsigned int status;

	status = reg_read(smbus, REG_SMSTA);

	while (!(status & SMSTA_XEN) && timeout--) {
		msleep(1);
		status = reg_read(smbus, REG_SMSTA);
	}

	/* Got NACK? */
	if (status & SMSTA_MTN)
		return -ENXIO;

	if (timeout < 0) {
		dev_warn(&smbus->dev->dev, "Timeout, status 0x%08x\n", status);
		reg_write(smbus, REG_SMSTA, status);
		return -ETIME;
	}

	/* Clear XEN */
	reg_write(smbus, REG_SMSTA, SMSTA_XEN);

	return 0;
}

static int pasemi_i2c_xfer_msg(struct i2c_adapter *adapter,
			       struct i2c_msg *msg, int stop)
{
	struct pasemi_smbus *smbus = adapter->algo_data;
	int read, i, err;
	u32 rd;

	read = msg->flags & I2C_M_RD ? 1 : 0;

	TXFIFO_WR(smbus, MTXFIFO_START | (msg->addr << 1) | read);

	if (read) {
		TXFIFO_WR(smbus, msg->len | MTXFIFO_READ |
				 (stop ? MTXFIFO_STOP : 0));

		err = pasemi_smb_waitready(smbus);
		if (err)
			goto reset_out;

		for (i = 0; i < msg->len; i++) {
			rd = RXFIFO_RD(smbus);
			if (rd & MRXFIFO_EMPTY) {
				err = -ENODATA;
				goto reset_out;
			}
			msg->buf[i] = rd & MRXFIFO_DATA_M;
		}
	} else {
		for (i = 0; i < msg->len - 1; i++)
			TXFIFO_WR(smbus, msg->buf[i]);

		TXFIFO_WR(smbus, msg->buf[msg->len-1] |
			  (stop ? MTXFIFO_STOP : 0));
	}

	return 0;

 reset_out:
	reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
		  (CLK_100K_DIV & CTL_CLK_M)));
	return err;
}

static int pasemi_i2c_xfer(struct i2c_adapter *adapter,
			   struct i2c_msg *msgs, int num)
{
	struct pasemi_smbus *smbus = adapter->algo_data;
	int ret, i;

	pasemi_smb_clear(smbus);

	ret = 0;

	for (i = 0; i < num && !ret; i++)
		ret = pasemi_i2c_xfer_msg(adapter, &msgs[i], (i == (num - 1)));

	return ret ? ret : num;
}

static int pasemi_smb_xfer(struct i2c_adapter *adapter,
		u16 addr, unsigned short flags, char read_write, u8 command,
		int size, union i2c_smbus_data *data)
{
	struct pasemi_smbus *smbus = adapter->algo_data;
	unsigned int rd;
	int read_flag, err;
	int len = 0, i;

	/* All our ops take 8-bit shifted addresses */
	addr <<= 1;
	read_flag = read_write == I2C_SMBUS_READ;

	pasemi_smb_clear(smbus);

	switch (size) {
	case I2C_SMBUS_QUICK:
		TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START |
			  MTXFIFO_STOP);
		break;
	case I2C_SMBUS_BYTE:
		TXFIFO_WR(smbus, addr | read_flag | MTXFIFO_START);
		if (read_write)
			TXFIFO_WR(smbus, 1 | MTXFIFO_STOP | MTXFIFO_READ);
		else
			TXFIFO_WR(smbus, MTXFIFO_STOP | command);
		break;
	case I2C_SMBUS_BYTE_DATA:
		TXFIFO_WR(smbus, addr | MTXFIFO_START);
		TXFIFO_WR(smbus, command);
		if (read_write) {
			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
			TXFIFO_WR(smbus, 1 | MTXFIFO_READ | MTXFIFO_STOP);
		} else {
			TXFIFO_WR(smbus, MTXFIFO_STOP | data->byte);
		}
		break;
	case I2C_SMBUS_WORD_DATA:
		TXFIFO_WR(smbus, addr | MTXFIFO_START);
		TXFIFO_WR(smbus, command);
		if (read_write) {
			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
			TXFIFO_WR(smbus, 2 | MTXFIFO_READ | MTXFIFO_STOP);
		} else {
			TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
			TXFIFO_WR(smbus, MTXFIFO_STOP | (data->word >> 8));
		}
		break;
	case I2C_SMBUS_BLOCK_DATA:
		TXFIFO_WR(smbus, addr | MTXFIFO_START);
		TXFIFO_WR(smbus, command);
		if (read_write) {
			TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
			TXFIFO_WR(smbus, 1 | MTXFIFO_READ);
			rd = RXFIFO_RD(smbus);
			len = min_t(u8, (rd & MRXFIFO_DATA_M),
				    I2C_SMBUS_BLOCK_MAX);
			TXFIFO_WR(smbus, len | MTXFIFO_READ |
					 MTXFIFO_STOP);
		} else {
			len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX);
			TXFIFO_WR(smbus, len);
			for (i = 1; i < len; i++)
				TXFIFO_WR(smbus, data->block[i]);
			TXFIFO_WR(smbus, data->block[len] | MTXFIFO_STOP);
		}
		break;
	case I2C_SMBUS_PROC_CALL:
		read_write = I2C_SMBUS_READ;
		TXFIFO_WR(smbus, addr | MTXFIFO_START);
		TXFIFO_WR(smbus, command);
		TXFIFO_WR(smbus, data->word & MTXFIFO_DATA_M);
		TXFIFO_WR(smbus, (data->word >> 8) & MTXFIFO_DATA_M);
		TXFIFO_WR(smbus, addr | I2C_SMBUS_READ | MTXFIFO_START);
		TXFIFO_WR(smbus, 2 | MTXFIFO_STOP | MTXFIFO_READ);
		break;
	case I2C_SMBUS_BLOCK_PROC_CALL:
		len = min_t(u8, data->block[0], I2C_SMBUS_BLOCK_MAX - 1);
		read_write = I2C_SMBUS_READ;
		TXFIFO_WR(smbus, addr | MTXFIFO_START);
		TXFIFO_WR(smbus, command);
		TXFIFO_WR(smbus, len);
		for (i = 1; i <= len; i++)
			TXFIFO_WR(smbus, data->block[i]);
		TXFIFO_WR(smbus, addr | I2C_SMBUS_READ);
		TXFIFO_WR(smbus, MTXFIFO_READ | 1);
		rd = RXFIFO_RD(smbus);
		len = min_t(u8, (rd & MRXFIFO_DATA_M),
			    I2C_SMBUS_BLOCK_MAX - len);
		TXFIFO_WR(smbus, len | MTXFIFO_READ | MTXFIFO_STOP);
		break;

	default:
		dev_warn(&adapter->dev, "Unsupported transaction %d\n", size);
		return -EINVAL;
	}

	err = pasemi_smb_waitready(smbus);
	if (err)
		goto reset_out;

	if (read_write == I2C_SMBUS_WRITE)
		return 0;

	switch (size) {
	case I2C_SMBUS_BYTE:
	case I2C_SMBUS_BYTE_DATA:
		rd = RXFIFO_RD(smbus);
		if (rd & MRXFIFO_EMPTY) {
			err = -ENODATA;
			goto reset_out;
		}
		data->byte = rd & MRXFIFO_DATA_M;
		break;
	case I2C_SMBUS_WORD_DATA:
	case I2C_SMBUS_PROC_CALL:
		rd = RXFIFO_RD(smbus);
		if (rd & MRXFIFO_EMPTY) {
			err = -ENODATA;
			goto reset_out;
		}
		data->word = rd & MRXFIFO_DATA_M;
		rd = RXFIFO_RD(smbus);
		if (rd & MRXFIFO_EMPTY) {
			err = -ENODATA;
			goto reset_out;
		}
		data->word |= (rd & MRXFIFO_DATA_M) << 8;
		break;
	case I2C_SMBUS_BLOCK_DATA:
	case I2C_SMBUS_BLOCK_PROC_CALL:
		data->block[0] = len;
		for (i = 1; i <= len; i ++) {
			rd = RXFIFO_RD(smbus);
			if (rd & MRXFIFO_EMPTY) {
				err = -ENODATA;
				goto reset_out;
			}
			data->block[i] = rd & MRXFIFO_DATA_M;
		}
		break;
	}

	return 0;

 reset_out:
	reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
		  (CLK_100K_DIV & CTL_CLK_M)));
	return err;
}

static u32 pasemi_smb_func(struct i2c_adapter *adapter)
{
	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
	       I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
	       I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_PROC_CALL |
	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL | I2C_FUNC_I2C;
}

static const struct i2c_algorithm smbus_algorithm = {
	.master_xfer	= pasemi_i2c_xfer,
	.smbus_xfer	= pasemi_smb_xfer,
	.functionality	= pasemi_smb_func,
};

static int __devinit pasemi_smb_probe(struct pci_dev *dev,
				      const struct pci_device_id *id)
{
	struct pasemi_smbus *smbus;
	int error;

	if (!(pci_resource_flags(dev, 0) & IORESOURCE_IO))
		return -ENODEV;

	smbus = kzalloc(sizeof(struct pasemi_smbus), GFP_KERNEL);
	if (!smbus)
		return -ENOMEM;

	smbus->dev = dev;
	smbus->base = pci_resource_start(dev, 0);
	smbus->size = pci_resource_len(dev, 0);

	if (!request_region(smbus->base, smbus->size,
			    pasemi_smb_driver.name)) {
		error = -EBUSY;
		goto out_kfree;
	}

	smbus->adapter.owner = THIS_MODULE;
	snprintf(smbus->adapter.name, sizeof(smbus->adapter.name),
		 "PA Semi SMBus adapter at 0x%lx", smbus->base);
	smbus->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
	smbus->adapter.algo = &smbus_algorithm;
	smbus->adapter.algo_data = smbus;
	smbus->adapter.nr = PCI_FUNC(dev->devfn);

	/* set up the sysfs linkage to our parent device */
	smbus->adapter.dev.parent = &dev->dev;

	reg_write(smbus, REG_CTL, (CTL_MTR | CTL_MRR |
		  (CLK_100K_DIV & CTL_CLK_M)));

	error = i2c_add_numbered_adapter(&smbus->adapter);
	if (error)
		goto out_release_region;

	pci_set_drvdata(dev, smbus);

	return 0;

 out_release_region:
	release_region(smbus->base, smbus->size);
 out_kfree:
	kfree(smbus);
	return error;
}

static void __devexit pasemi_smb_remove(struct pci_dev *dev)
{
	struct pasemi_smbus *smbus = pci_get_drvdata(dev);

	i2c_del_adapter(&smbus->adapter);
	release_region(smbus->base, smbus->size);
	kfree(smbus);
}

static const struct pci_device_id pasemi_smb_ids[] = {
	{ PCI_DEVICE(0x1959, 0xa003) },
	{ 0, }
};

MODULE_DEVICE_TABLE(pci, pasemi_smb_ids);

static struct pci_driver pasemi_smb_driver = {
	.name		= "i2c-pasemi",
	.id_table	= pasemi_smb_ids,
	.probe		= pasemi_smb_probe,
	.remove		= __devexit_p(pasemi_smb_remove),
};

static int __init pasemi_smb_init(void)
{
	return pci_register_driver(&pasemi_smb_driver);
}

static void __exit pasemi_smb_exit(void)
{
	pci_unregister_driver(&pasemi_smb_driver);
}

MODULE_LICENSE("GPL");
MODULE_AUTHOR ("Olof Johansson <olof@lixom.net>");
MODULE_DESCRIPTION("PA Semi PWRficient SMBus driver");

module_init(pasemi_smb_init);
module_exit(pasemi_smb_exit);