summaryrefslogtreecommitdiffstats
path: root/drivers/i2c/busses/i2c-diolan-u2c.c
blob: 7eb19a5222f29d03e0c553fa5fc38ee1ddb7363c (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
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
/*
 * Driver for the Diolan u2c-12 USB-I2C adapter
 *
 * Copyright (c) 2010-2011 Ericsson AB
 *
 * Derived from:
 *  i2c-tiny-usb.c
 *  Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
 *
 * 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, version 2.
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/usb.h>
#include <linux/i2c.h>

#define DRIVER_NAME		"i2c-diolan-u2c"

#define USB_VENDOR_ID_DIOLAN		0x0abf
#define USB_DEVICE_ID_DIOLAN_U2C	0x3370

#define DIOLAN_OUT_EP		0x02
#define DIOLAN_IN_EP		0x84

/* commands via USB, must match command ids in the firmware */
#define CMD_I2C_READ		0x01
#define CMD_I2C_WRITE		0x02
#define CMD_I2C_SCAN		0x03	/* Returns list of detected devices */
#define CMD_I2C_RELEASE_SDA	0x04
#define CMD_I2C_RELEASE_SCL	0x05
#define CMD_I2C_DROP_SDA	0x06
#define CMD_I2C_DROP_SCL	0x07
#define CMD_I2C_READ_SDA	0x08
#define CMD_I2C_READ_SCL	0x09
#define CMD_GET_FW_VERSION	0x0a
#define CMD_GET_SERIAL		0x0b
#define CMD_I2C_START		0x0c
#define CMD_I2C_STOP		0x0d
#define CMD_I2C_REPEATED_START	0x0e
#define CMD_I2C_PUT_BYTE	0x0f
#define CMD_I2C_GET_BYTE	0x10
#define CMD_I2C_PUT_ACK		0x11
#define CMD_I2C_GET_ACK		0x12
#define CMD_I2C_PUT_BYTE_ACK	0x13
#define CMD_I2C_GET_BYTE_ACK	0x14
#define CMD_I2C_SET_SPEED	0x1b
#define CMD_I2C_GET_SPEED	0x1c
#define CMD_I2C_SET_CLK_SYNC	0x24
#define CMD_I2C_GET_CLK_SYNC	0x25
#define CMD_I2C_SET_CLK_SYNC_TO	0x26
#define CMD_I2C_GET_CLK_SYNC_TO	0x27

#define RESP_OK			0x00
#define RESP_FAILED		0x01
#define RESP_BAD_MEMADDR	0x04
#define RESP_DATA_ERR		0x05
#define RESP_NOT_IMPLEMENTED	0x06
#define RESP_NACK		0x07
#define RESP_TIMEOUT		0x09

#define U2C_I2C_SPEED_FAST	0	/* 400 kHz */
#define U2C_I2C_SPEED_STD	1	/* 100 kHz */
#define U2C_I2C_SPEED_2KHZ	242	/* 2 kHz, minimum speed */
#define U2C_I2C_SPEED(f)	((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)

#define U2C_I2C_FREQ_FAST	400000
#define U2C_I2C_FREQ_STD	100000
#define U2C_I2C_FREQ(s)		(1000000 / (2 * (s - 1) + 10))

#define DIOLAN_USB_TIMEOUT	100	/* in ms */
#define DIOLAN_SYNC_TIMEOUT	20	/* in ms */

#define DIOLAN_OUTBUF_LEN	128
#define DIOLAN_FLUSH_LEN	(DIOLAN_OUTBUF_LEN - 4)
#define DIOLAN_INBUF_LEN	256	/* Maximum supported receive length */

/* Structure to hold all of our device specific stuff */
struct i2c_diolan_u2c {
	u8 obuffer[DIOLAN_OUTBUF_LEN];	/* output buffer */
	u8 ibuffer[DIOLAN_INBUF_LEN];	/* input buffer */
	struct usb_device *usb_dev;	/* the usb device for this device */
	struct usb_interface *interface;/* the interface for this device */
	struct i2c_adapter adapter;	/* i2c related things */
	int olen;			/* Output buffer length */
	int ocount;			/* Number of enqueued messages */
};

static uint frequency = U2C_I2C_FREQ_STD;	/* I2C clock frequency in Hz */

module_param(frequency, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");

/* usb layer */

/* Send command to device, and get response. */
static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
{
	int ret = 0;
	int actual;
	int i;

	if (!dev->olen || !dev->ocount)
		return -EINVAL;

	ret = usb_bulk_msg(dev->usb_dev,
			   usb_sndbulkpipe(dev->usb_dev, DIOLAN_OUT_EP),
			   dev->obuffer, dev->olen, &actual,
			   DIOLAN_USB_TIMEOUT);
	if (!ret) {
		for (i = 0; i < dev->ocount; i++) {
			int tmpret;

			tmpret = usb_bulk_msg(dev->usb_dev,
					      usb_rcvbulkpipe(dev->usb_dev,
							      DIOLAN_IN_EP),
					      dev->ibuffer,
					      sizeof(dev->ibuffer), &actual,
					      DIOLAN_USB_TIMEOUT);
			/*
			 * Stop command processing if a previous command
			 * returned an error.
			 * Note that we still need to retrieve all messages.
			 */
			if (ret < 0)
				continue;
			ret = tmpret;
			if (ret == 0 && actual > 0) {
				switch (dev->ibuffer[actual - 1]) {
				case RESP_NACK:
					/*
					 * Return ENXIO if NACK was received as
					 * response to the address phase,
					 * EIO otherwise
					 */
					ret = i == 1 ? -ENXIO : -EIO;
					break;
				case RESP_TIMEOUT:
					ret = -ETIMEDOUT;
					break;
				case RESP_OK:
					/* strip off return code */
					ret = actual - 1;
					break;
				default:
					ret = -EIO;
					break;
				}
			}
		}
	}
	dev->olen = 0;
	dev->ocount = 0;
	return ret;
}

static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
{
	if (flush || dev->olen >= DIOLAN_FLUSH_LEN)
		return diolan_usb_transfer(dev);
	return 0;
}

/* Send command (no data) */
static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
{
	dev->obuffer[dev->olen++] = command;
	dev->ocount++;
	return diolan_write_cmd(dev, flush);
}

/* Send command with one byte of data */
static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
			       bool flush)
{
	dev->obuffer[dev->olen++] = command;
	dev->obuffer[dev->olen++] = data;
	dev->ocount++;
	return diolan_write_cmd(dev, flush);
}

/* Send command with two bytes of data */
static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
				u8 d2, bool flush)
{
	dev->obuffer[dev->olen++] = command;
	dev->obuffer[dev->olen++] = d1;
	dev->obuffer[dev->olen++] = d2;
	dev->ocount++;
	return diolan_write_cmd(dev, flush);
}

/*
 * Flush input queue.
 * If we don't do this at startup and the controller has queued up
 * messages which were not retrieved, it will stop responding
 * at some point.
 */
static void diolan_flush_input(struct i2c_diolan_u2c *dev)
{
	int i;

	for (i = 0; i < 10; i++) {
		int actual = 0;
		int ret;

		ret = usb_bulk_msg(dev->usb_dev,
				   usb_rcvbulkpipe(dev->usb_dev, DIOLAN_IN_EP),
				   dev->ibuffer, sizeof(dev->ibuffer), &actual,
				   DIOLAN_USB_TIMEOUT);
		if (ret < 0 || actual == 0)
			break;
	}
	if (i == 10)
		dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
}

static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
{
	return diolan_usb_cmd(dev, CMD_I2C_START, false);
}

static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
{
	return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
}

static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
{
	return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
}

static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
				   u8 *byte)
{
	int ret;

	ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
	if (ret > 0)
		*byte = dev->ibuffer[0];
	else if (ret == 0)
		ret = -EIO;

	return ret;
}

static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
{
	return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
}

static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
{
	return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
}

/* Enable or disable clock synchronization (stretching) */
static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
{
	return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
}

/* Set clock synchronization timeout in ms */
static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
{
	int to_val = ms * 10;

	return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
				    to_val & 0xff, (to_val >> 8) & 0xff, true);
}

static void diolan_fw_version(struct i2c_diolan_u2c *dev)
{
	int ret;

	ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
	if (ret >= 2)
		dev_info(&dev->interface->dev,
			 "Diolan U2C firmware version %u.%u\n",
			 (unsigned int)dev->ibuffer[0],
			 (unsigned int)dev->ibuffer[1]);
}

static void diolan_get_serial(struct i2c_diolan_u2c *dev)
{
	int ret;
	u32 serial;

	ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
	if (ret >= 4) {
		serial = le32_to_cpu(*(u32 *)dev->ibuffer);
		dev_info(&dev->interface->dev,
			 "Diolan U2C serial number %u\n", serial);
	}
}

static int diolan_init(struct i2c_diolan_u2c *dev)
{
	int speed, ret;

	if (frequency >= 200000) {
		speed = U2C_I2C_SPEED_FAST;
		frequency = U2C_I2C_FREQ_FAST;
	} else if (frequency >= 100000 || frequency == 0) {
		speed = U2C_I2C_SPEED_STD;
		frequency = U2C_I2C_FREQ_STD;
	} else {
		speed = U2C_I2C_SPEED(frequency);
		if (speed > U2C_I2C_SPEED_2KHZ)
			speed = U2C_I2C_SPEED_2KHZ;
		frequency = U2C_I2C_FREQ(speed);
	}

	dev_info(&dev->interface->dev,
		 "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
		 dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);

	diolan_flush_input(dev);
	diolan_fw_version(dev);
	diolan_get_serial(dev);

	/* Set I2C speed */
	ret = diolan_set_speed(dev, speed);
	if (ret < 0)
		return ret;

	/* Configure I2C clock synchronization */
	ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);
	if (ret < 0)
		return ret;

	if (speed != U2C_I2C_SPEED_FAST)
		ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);

	return ret;
}

/* i2c layer */

static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
			   int num)
{
	struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
	struct i2c_msg *pmsg;
	int i, j;
	int ret, sret;

	ret = diolan_i2c_start(dev);
	if (ret < 0)
		return ret;

	for (i = 0; i < num; i++) {
		pmsg = &msgs[i];
		if (i) {
			ret = diolan_i2c_repeated_start(dev);
			if (ret < 0)
				goto abort;
		}
		if (pmsg->flags & I2C_M_RD) {
			ret =
			    diolan_i2c_put_byte_ack(dev, (pmsg->addr << 1) | 1);
			if (ret < 0)
				goto abort;
			for (j = 0; j < pmsg->len; j++) {
				u8 byte;
				bool ack = j < pmsg->len - 1;

				/*
				 * Don't send NACK if this is the first byte
				 * of a SMBUS_BLOCK message.
				 */
				if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
					ack = true;

				ret = diolan_i2c_get_byte_ack(dev, ack, &byte);
				if (ret < 0)
					goto abort;
				/*
				 * Adjust count if first received byte is length
				 */
				if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
					if (byte == 0
					    || byte > I2C_SMBUS_BLOCK_MAX) {
						ret = -EPROTO;
						goto abort;
					}
					pmsg->len += byte;
				}
				pmsg->buf[j] = byte;
			}
		} else {
			ret = diolan_i2c_put_byte_ack(dev, pmsg->addr << 1);
			if (ret < 0)
				goto abort;
			for (j = 0; j < pmsg->len; j++) {
				ret = diolan_i2c_put_byte_ack(dev,
							      pmsg->buf[j]);
				if (ret < 0)
					goto abort;
			}
		}
	}
abort:
	sret = diolan_i2c_stop(dev);
	if (sret < 0 && ret >= 0)
		ret = sret;
	return ret;
}

/*
 * Return list of supported functionality.
 */
static u32 diolan_usb_func(struct i2c_adapter *a)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
	       I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
}

static const struct i2c_algorithm diolan_usb_algorithm = {
	.master_xfer = diolan_usb_xfer,
	.functionality = diolan_usb_func,
};

/* device layer */

static const struct usb_device_id diolan_u2c_table[] = {
	{ USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
	{ }
};

MODULE_DEVICE_TABLE(usb, diolan_u2c_table);

static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
{
	usb_put_dev(dev->usb_dev);
	kfree(dev);
}

static int diolan_u2c_probe(struct usb_interface *interface,
			    const struct usb_device_id *id)
{
	struct i2c_diolan_u2c *dev;
	int ret;

	/* allocate memory for our device state and initialize it */
	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
	if (dev == NULL) {
		dev_err(&interface->dev, "no memory for device state\n");
		ret = -ENOMEM;
		goto error;
	}

	dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
	dev->interface = interface;

	/* save our data pointer in this interface device */
	usb_set_intfdata(interface, dev);

	/* setup i2c adapter description */
	dev->adapter.owner = THIS_MODULE;
	dev->adapter.class = I2C_CLASS_HWMON;
	dev->adapter.algo = &diolan_usb_algorithm;
	i2c_set_adapdata(&dev->adapter, dev);
	snprintf(dev->adapter.name, sizeof(dev->adapter.name),
		 DRIVER_NAME " at bus %03d device %03d",
		 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);

	dev->adapter.dev.parent = &dev->interface->dev;

	/* initialize diolan i2c interface */
	ret = diolan_init(dev);
	if (ret < 0) {
		dev_err(&interface->dev, "failed to initialize adapter\n");
		goto error_free;
	}

	/* and finally attach to i2c layer */
	ret = i2c_add_adapter(&dev->adapter);
	if (ret < 0) {
		dev_err(&interface->dev, "failed to add I2C adapter\n");
		goto error_free;
	}

	dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");

	return 0;

error_free:
	usb_set_intfdata(interface, NULL);
	diolan_u2c_free(dev);
error:
	return ret;
}

static void diolan_u2c_disconnect(struct usb_interface *interface)
{
	struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);

	i2c_del_adapter(&dev->adapter);
	usb_set_intfdata(interface, NULL);
	diolan_u2c_free(dev);

	dev_dbg(&interface->dev, "disconnected\n");
}

static struct usb_driver diolan_u2c_driver = {
	.name = DRIVER_NAME,
	.probe = diolan_u2c_probe,
	.disconnect = diolan_u2c_disconnect,
	.id_table = diolan_u2c_table,
};

module_usb_driver(diolan_u2c_driver);

MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
MODULE_DESCRIPTION(DRIVER_NAME " driver");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud