summaryrefslogtreecommitdiff
path: root/drivers/i2c/busses/i2c-viperboard.c
blob: e4be86b3de9a28b201bcd197470ab3a3a78ee683 (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
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
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
/*
 *  Nano River Technologies viperboard i2c master driver
 *
 *  (C) 2012 by Lemonage GmbH
 *  Author: Lars Poeschel <poeschel@lemonage.de>
 *  All rights reserved.
 *
 *  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.
 *
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>

#include <linux/usb.h>
#include <linux/i2c.h>

#include <linux/mfd/viperboard.h>

struct vprbrd_i2c {
	struct i2c_adapter i2c;
	u8 bus_freq_param;
};

/* i2c bus frequency module parameter */
static u8 i2c_bus_param;
static unsigned int i2c_bus_freq = 100;
module_param(i2c_bus_freq, int, 0);
MODULE_PARM_DESC(i2c_bus_freq,
	"i2c bus frequency in khz (default is 100) valid values: 10, 100, 200, 400, 1000, 3000, 6000");

static int vprbrd_i2c_status(struct i2c_adapter *i2c,
	struct vprbrd_i2c_status *status, bool prev_error)
{
	u16 bytes_xfer;
	int ret;
	struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;

	/* check for protocol error */
	bytes_xfer = sizeof(struct vprbrd_i2c_status);

	ret = usb_control_msg(vb->usb_dev, usb_rcvctrlpipe(vb->usb_dev, 0),
		VPRBRD_USB_REQUEST_I2C, VPRBRD_USB_TYPE_IN, 0x0000, 0x0000,
		status, bytes_xfer, VPRBRD_USB_TIMEOUT_MS);

	if (ret != bytes_xfer)
		prev_error = true;

	if (prev_error) {
		dev_err(&i2c->dev, "failure in usb communication\n");
		return -EREMOTEIO;
	}

	dev_dbg(&i2c->dev, "  status = %d\n", status->status);
	if (status->status != 0x00) {
		dev_err(&i2c->dev, "failure: i2c protocol error\n");
		return -EPROTO;
	}
	return 0;
}

static int vprbrd_i2c_receive(struct usb_device *usb_dev,
	struct vprbrd_i2c_read_msg *rmsg, int bytes_xfer)
{
	int ret, bytes_actual;
	int error = 0;

	/* send the read request */
	ret = usb_bulk_msg(usb_dev,
		usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), rmsg,
		sizeof(struct vprbrd_i2c_read_hdr), &bytes_actual,
		VPRBRD_USB_TIMEOUT_MS);

	if ((ret < 0)
		|| (bytes_actual != sizeof(struct vprbrd_i2c_read_hdr))) {
		dev_err(&usb_dev->dev, "failure transmitting usb\n");
		error = -EREMOTEIO;
	}

	/* read the actual data */
	ret = usb_bulk_msg(usb_dev,
		usb_rcvbulkpipe(usb_dev, VPRBRD_EP_IN), rmsg,
		bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);

	if ((ret < 0) || (bytes_xfer != bytes_actual)) {
		dev_err(&usb_dev->dev, "failure receiving usb\n");
		error = -EREMOTEIO;
	}
	return error;
}

static int vprbrd_i2c_addr(struct usb_device *usb_dev,
	struct vprbrd_i2c_addr_msg *amsg)
{
	int ret, bytes_actual;

	ret = usb_bulk_msg(usb_dev,
		usb_sndbulkpipe(usb_dev, VPRBRD_EP_OUT), amsg,
		sizeof(struct vprbrd_i2c_addr_msg), &bytes_actual,
		VPRBRD_USB_TIMEOUT_MS);

	if ((ret < 0) ||
			(sizeof(struct vprbrd_i2c_addr_msg) != bytes_actual)) {
		dev_err(&usb_dev->dev, "failure transmitting usb\n");
		return -EREMOTEIO;
	}
	return 0;
}

static int vprbrd_i2c_read(struct vprbrd *vb, struct i2c_msg *msg)
{
	int ret;
	u16 remain_len, len1, len2, start = 0x0000;
	struct vprbrd_i2c_read_msg *rmsg =
		(struct vprbrd_i2c_read_msg *)vb->buf;

	remain_len = msg->len;
	rmsg->header.cmd = VPRBRD_I2C_CMD_READ;
	while (remain_len > 0) {
		rmsg->header.addr = cpu_to_le16(start + 0x4000);
		if (remain_len <= 255) {
			len1 = remain_len;
			len2 = 0x00;
			rmsg->header.len0 = remain_len;
			rmsg->header.len1 = 0x00;
			rmsg->header.len2 = 0x00;
			rmsg->header.len3 = 0x00;
			rmsg->header.len4 = 0x00;
			rmsg->header.len5 = 0x00;
			remain_len = 0;
		} else if (remain_len <= 510) {
			len1 = remain_len;
			len2 = 0x00;
			rmsg->header.len0 = remain_len - 255;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0x00;
			rmsg->header.len3 = 0x00;
			rmsg->header.len4 = 0x00;
			rmsg->header.len5 = 0x00;
			remain_len = 0;
		} else if (remain_len <= 512) {
			len1 = remain_len;
			len2 = 0x00;
			rmsg->header.len0 = remain_len - 510;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0xff;
			rmsg->header.len3 = 0x00;
			rmsg->header.len4 = 0x00;
			rmsg->header.len5 = 0x00;
			remain_len = 0;
		} else if (remain_len <= 767) {
			len1 = 512;
			len2 = remain_len - 512;
			rmsg->header.len0 = 0x02;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0xff;
			rmsg->header.len3 = remain_len - 512;
			rmsg->header.len4 = 0x00;
			rmsg->header.len5 = 0x00;
			remain_len = 0;
		} else if (remain_len <= 1022) {
			len1 = 512;
			len2 = remain_len - 512;
			rmsg->header.len0 = 0x02;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0xff;
			rmsg->header.len3 = remain_len - 767;
			rmsg->header.len4 = 0xff;
			rmsg->header.len5 = 0x00;
			remain_len = 0;
		} else if (remain_len <= 1024) {
			len1 = 512;
			len2 = remain_len - 512;
			rmsg->header.len0 = 0x02;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0xff;
			rmsg->header.len3 = remain_len - 1022;
			rmsg->header.len4 = 0xff;
			rmsg->header.len5 = 0xff;
			remain_len = 0;
		} else {
			len1 = 512;
			len2 = 512;
			rmsg->header.len0 = 0x02;
			rmsg->header.len1 = 0xff;
			rmsg->header.len2 = 0xff;
			rmsg->header.len3 = 0x02;
			rmsg->header.len4 = 0xff;
			rmsg->header.len5 = 0xff;
			remain_len -= 1024;
			start += 1024;
		}
		rmsg->header.tf1 = cpu_to_le16(len1);
		rmsg->header.tf2 = cpu_to_le16(len2);

		/* first read transfer */
		ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len1);
		if (ret < 0)
			return ret;
		/* copy the received data */
		memcpy(msg->buf + start, rmsg, len1);

		/* second read transfer if neccessary */
		if (len2 > 0) {
			ret = vprbrd_i2c_receive(vb->usb_dev, rmsg, len2);
			if (ret < 0)
				return ret;
			/* copy the received data */
			memcpy(msg->buf + start + 512, rmsg, len2);
		}
	}
	return 0;
}

static int vprbrd_i2c_write(struct vprbrd *vb, struct i2c_msg *msg)
{
	int ret, bytes_actual;
	u16 remain_len, bytes_xfer,
		start = 0x0000;
	struct vprbrd_i2c_write_msg *wmsg =
		(struct vprbrd_i2c_write_msg *)vb->buf;

	remain_len = msg->len;
	wmsg->header.cmd = VPRBRD_I2C_CMD_WRITE;
	wmsg->header.last = 0x00;
	wmsg->header.chan = 0x00;
	wmsg->header.spi = 0x0000;
	while (remain_len > 0) {
		wmsg->header.addr = cpu_to_le16(start + 0x4000);
		if (remain_len > 503) {
			wmsg->header.len1 = 0xff;
			wmsg->header.len2 = 0xf8;
			remain_len -= 503;
			bytes_xfer = 503 + sizeof(struct vprbrd_i2c_write_hdr);
			start += 503;
		} else if (remain_len > 255) {
			wmsg->header.len1 = 0xff;
			wmsg->header.len2 = (remain_len - 255);
			bytes_xfer = remain_len +
				sizeof(struct vprbrd_i2c_write_hdr);
			remain_len = 0;
		} else {
			wmsg->header.len1 = remain_len;
			wmsg->header.len2 = 0x00;
			bytes_xfer = remain_len +
				sizeof(struct vprbrd_i2c_write_hdr);
			remain_len = 0;
		}
		memcpy(wmsg->data, msg->buf + start,
			bytes_xfer - sizeof(struct vprbrd_i2c_write_hdr));

		ret = usb_bulk_msg(vb->usb_dev,
			usb_sndbulkpipe(vb->usb_dev,
			VPRBRD_EP_OUT), wmsg,
			bytes_xfer, &bytes_actual, VPRBRD_USB_TIMEOUT_MS);
		if ((ret < 0) || (bytes_xfer != bytes_actual))
			return -EREMOTEIO;
	}
	return 0;
}

static int vprbrd_i2c_xfer(struct i2c_adapter *i2c, struct i2c_msg *msgs,
		int num)
{
	struct i2c_msg *pmsg;
	int i, ret,
		error = 0;
	struct vprbrd *vb = (struct vprbrd *)i2c->algo_data;
	struct vprbrd_i2c_addr_msg *amsg =
		(struct vprbrd_i2c_addr_msg *)vb->buf;
	struct vprbrd_i2c_status *smsg = (struct vprbrd_i2c_status *)vb->buf;

	dev_dbg(&i2c->dev, "master xfer %d messages:\n", num);

	for (i = 0 ; i < num ; i++) {
		pmsg = &msgs[i];

		dev_dbg(&i2c->dev,
			"  %d: %s (flags %d) %d bytes to 0x%02x\n",
			i, pmsg->flags & I2C_M_RD ? "read" : "write",
			pmsg->flags, pmsg->len, pmsg->addr);

		mutex_lock(&vb->lock);
		/* directly send the message */
		if (pmsg->flags & I2C_M_RD) {
			/* read data */
			amsg->cmd = VPRBRD_I2C_CMD_ADDR;
			amsg->unknown2 = 0x00;
			amsg->unknown3 = 0x00;
			amsg->addr = pmsg->addr;
			amsg->unknown1 = 0x01;
			amsg->len = cpu_to_le16(pmsg->len);
			/* send the addr and len, we're interested to board */
			ret = vprbrd_i2c_addr(vb->usb_dev, amsg);
			if (ret < 0)
				error = ret;

			ret = vprbrd_i2c_read(vb, pmsg);
			if (ret < 0)
				error = ret;

			ret = vprbrd_i2c_status(i2c, smsg, error);
			if (ret < 0)
				error = ret;
			/* in case of protocol error, return the error */
			if (error < 0)
				goto error;
		} else {
			/* write data */
			ret = vprbrd_i2c_write(vb, pmsg);

			amsg->cmd = VPRBRD_I2C_CMD_ADDR;
			amsg->unknown2 = 0x00;
			amsg->unknown3 = 0x00;
			amsg->addr = pmsg->addr;
			amsg->unknown1 = 0x00;
			amsg->len = cpu_to_le16(pmsg->len);
			/* send the addr, the data goes to to board */
			ret = vprbrd_i2c_addr(vb->usb_dev, amsg);
			if (ret < 0)
				error = ret;

			ret = vprbrd_i2c_status(i2c, smsg, error);
			if (ret < 0)
				error = ret;

			if (error < 0)
				goto error;
		}
		mutex_unlock(&vb->lock);
	}
	return 0;
error:
	mutex_unlock(&vb->lock);
	return error;
}

static u32 vprbrd_i2c_func(struct i2c_adapter *i2c)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}

/* This is the actual algorithm we define */
static const struct i2c_algorithm vprbrd_algorithm = {
	.master_xfer	= vprbrd_i2c_xfer,
	.functionality	= vprbrd_i2c_func,
};

static const struct i2c_adapter_quirks vprbrd_quirks = {
	.max_read_len = 2048,
	.max_write_len = 2048,
};

static int vprbrd_i2c_probe(struct platform_device *pdev)
{
	struct vprbrd *vb = dev_get_drvdata(pdev->dev.parent);
	struct vprbrd_i2c *vb_i2c;
	int ret;
	int pipe;

	vb_i2c = devm_kzalloc(&pdev->dev, sizeof(*vb_i2c), GFP_KERNEL);
	if (vb_i2c == NULL)
		return -ENOMEM;

	/* setup i2c adapter description */
	vb_i2c->i2c.owner = THIS_MODULE;
	vb_i2c->i2c.class = I2C_CLASS_HWMON;
	vb_i2c->i2c.algo = &vprbrd_algorithm;
	vb_i2c->i2c.quirks = &vprbrd_quirks;
	vb_i2c->i2c.algo_data = vb;
	/* save the param in usb capabable memory */
	vb_i2c->bus_freq_param = i2c_bus_param;

	snprintf(vb_i2c->i2c.name, sizeof(vb_i2c->i2c.name),
		 "viperboard at bus %03d device %03d",
		 vb->usb_dev->bus->busnum, vb->usb_dev->devnum);

	/* setting the bus frequency */
	if ((i2c_bus_param <= VPRBRD_I2C_FREQ_10KHZ)
		&& (i2c_bus_param >= VPRBRD_I2C_FREQ_6MHZ)) {
		pipe = usb_sndctrlpipe(vb->usb_dev, 0);
		ret = usb_control_msg(vb->usb_dev, pipe,
			VPRBRD_USB_REQUEST_I2C_FREQ, VPRBRD_USB_TYPE_OUT,
			0x0000, 0x0000, &vb_i2c->bus_freq_param, 1,
			VPRBRD_USB_TIMEOUT_MS);
		if (ret != 1) {
			dev_err(&pdev->dev, "failure setting i2c_bus_freq to %d\n",
				i2c_bus_freq);
			return -EIO;
		}
	} else {
		dev_err(&pdev->dev,
			"invalid i2c_bus_freq setting:%d\n", i2c_bus_freq);
		return -EIO;
	}

	vb_i2c->i2c.dev.parent = &pdev->dev;

	/* attach to i2c layer */
	i2c_add_adapter(&vb_i2c->i2c);

	platform_set_drvdata(pdev, vb_i2c);

	return 0;
}

static int vprbrd_i2c_remove(struct platform_device *pdev)
{
	struct vprbrd_i2c *vb_i2c = platform_get_drvdata(pdev);

	i2c_del_adapter(&vb_i2c->i2c);

	return 0;
}

static struct platform_driver vprbrd_i2c_driver = {
	.driver.name	= "viperboard-i2c",
	.driver.owner	= THIS_MODULE,
	.probe		= vprbrd_i2c_probe,
	.remove		= vprbrd_i2c_remove,
};

static int __init vprbrd_i2c_init(void)
{
	switch (i2c_bus_freq) {
	case 6000:
		i2c_bus_param = VPRBRD_I2C_FREQ_6MHZ;
		break;
	case 3000:
		i2c_bus_param = VPRBRD_I2C_FREQ_3MHZ;
		break;
	case 1000:
		i2c_bus_param = VPRBRD_I2C_FREQ_1MHZ;
		break;
	case 400:
		i2c_bus_param = VPRBRD_I2C_FREQ_400KHZ;
		break;
	case 200:
		i2c_bus_param = VPRBRD_I2C_FREQ_200KHZ;
		break;
	case 100:
		i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;
		break;
	case 10:
		i2c_bus_param = VPRBRD_I2C_FREQ_10KHZ;
		break;
	default:
		pr_warn("invalid i2c_bus_freq (%d)\n", i2c_bus_freq);
		i2c_bus_param = VPRBRD_I2C_FREQ_100KHZ;
	}

	return platform_driver_register(&vprbrd_i2c_driver);
}
subsys_initcall(vprbrd_i2c_init);

static void __exit vprbrd_i2c_exit(void)
{
	platform_driver_unregister(&vprbrd_i2c_driver);
}
module_exit(vprbrd_i2c_exit);

MODULE_AUTHOR("Lars Poeschel <poeschel@lemonage.de>");
MODULE_DESCRIPTION("I2C master driver for Nano River Techs Viperboard");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:viperboard-i2c");