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Guenter Roeck335d7c52011-01-26 11:45:49 -08001/*
2 * Driver for the Diolan u2c-12 USB-I2C adapter
3 *
4 * Copyright (c) 2010-2011 Ericsson AB
5 *
6 * Derived from:
7 * i2c-tiny-usb.c
8 * Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation, version 2.
13 */
14
15#include <linux/kernel.h>
16#include <linux/errno.h>
17#include <linux/module.h>
18#include <linux/types.h>
19#include <linux/slab.h>
20#include <linux/usb.h>
21#include <linux/i2c.h>
22
23#define DRIVER_NAME "i2c-diolan-u2c"
24
25#define USB_VENDOR_ID_DIOLAN 0x0abf
26#define USB_DEVICE_ID_DIOLAN_U2C 0x3370
27
Guenter Roeck335d7c52011-01-26 11:45:49 -080028
29/* commands via USB, must match command ids in the firmware */
30#define CMD_I2C_READ 0x01
31#define CMD_I2C_WRITE 0x02
32#define CMD_I2C_SCAN 0x03 /* Returns list of detected devices */
33#define CMD_I2C_RELEASE_SDA 0x04
34#define CMD_I2C_RELEASE_SCL 0x05
35#define CMD_I2C_DROP_SDA 0x06
36#define CMD_I2C_DROP_SCL 0x07
37#define CMD_I2C_READ_SDA 0x08
38#define CMD_I2C_READ_SCL 0x09
39#define CMD_GET_FW_VERSION 0x0a
40#define CMD_GET_SERIAL 0x0b
41#define CMD_I2C_START 0x0c
42#define CMD_I2C_STOP 0x0d
43#define CMD_I2C_REPEATED_START 0x0e
44#define CMD_I2C_PUT_BYTE 0x0f
45#define CMD_I2C_GET_BYTE 0x10
46#define CMD_I2C_PUT_ACK 0x11
47#define CMD_I2C_GET_ACK 0x12
48#define CMD_I2C_PUT_BYTE_ACK 0x13
49#define CMD_I2C_GET_BYTE_ACK 0x14
50#define CMD_I2C_SET_SPEED 0x1b
51#define CMD_I2C_GET_SPEED 0x1c
52#define CMD_I2C_SET_CLK_SYNC 0x24
53#define CMD_I2C_GET_CLK_SYNC 0x25
54#define CMD_I2C_SET_CLK_SYNC_TO 0x26
55#define CMD_I2C_GET_CLK_SYNC_TO 0x27
56
57#define RESP_OK 0x00
58#define RESP_FAILED 0x01
59#define RESP_BAD_MEMADDR 0x04
60#define RESP_DATA_ERR 0x05
61#define RESP_NOT_IMPLEMENTED 0x06
62#define RESP_NACK 0x07
63#define RESP_TIMEOUT 0x09
64
65#define U2C_I2C_SPEED_FAST 0 /* 400 kHz */
66#define U2C_I2C_SPEED_STD 1 /* 100 kHz */
67#define U2C_I2C_SPEED_2KHZ 242 /* 2 kHz, minimum speed */
68#define U2C_I2C_SPEED(f) ((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)
69
70#define U2C_I2C_FREQ_FAST 400000
71#define U2C_I2C_FREQ_STD 100000
72#define U2C_I2C_FREQ(s) (1000000 / (2 * (s - 1) + 10))
73
74#define DIOLAN_USB_TIMEOUT 100 /* in ms */
75#define DIOLAN_SYNC_TIMEOUT 20 /* in ms */
76
77#define DIOLAN_OUTBUF_LEN 128
78#define DIOLAN_FLUSH_LEN (DIOLAN_OUTBUF_LEN - 4)
79#define DIOLAN_INBUF_LEN 256 /* Maximum supported receive length */
80
81/* Structure to hold all of our device specific stuff */
82struct i2c_diolan_u2c {
83 u8 obuffer[DIOLAN_OUTBUF_LEN]; /* output buffer */
84 u8 ibuffer[DIOLAN_INBUF_LEN]; /* input buffer */
Martin Vogt4e4844c2013-11-24 15:57:23 +010085 int ep_in, ep_out; /* Endpoints */
Guenter Roeck335d7c52011-01-26 11:45:49 -080086 struct usb_device *usb_dev; /* the usb device for this device */
87 struct usb_interface *interface;/* the interface for this device */
88 struct i2c_adapter adapter; /* i2c related things */
89 int olen; /* Output buffer length */
90 int ocount; /* Number of enqueued messages */
91};
92
93static uint frequency = U2C_I2C_FREQ_STD; /* I2C clock frequency in Hz */
94
95module_param(frequency, uint, S_IRUGO | S_IWUSR);
96MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
97
98/* usb layer */
99
100/* Send command to device, and get response. */
101static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
102{
103 int ret = 0;
104 int actual;
105 int i;
106
107 if (!dev->olen || !dev->ocount)
108 return -EINVAL;
109
110 ret = usb_bulk_msg(dev->usb_dev,
Martin Vogt4e4844c2013-11-24 15:57:23 +0100111 usb_sndbulkpipe(dev->usb_dev, dev->ep_out),
Guenter Roeck335d7c52011-01-26 11:45:49 -0800112 dev->obuffer, dev->olen, &actual,
113 DIOLAN_USB_TIMEOUT);
114 if (!ret) {
115 for (i = 0; i < dev->ocount; i++) {
116 int tmpret;
117
118 tmpret = usb_bulk_msg(dev->usb_dev,
119 usb_rcvbulkpipe(dev->usb_dev,
Martin Vogt4e4844c2013-11-24 15:57:23 +0100120 dev->ep_in),
Guenter Roeck335d7c52011-01-26 11:45:49 -0800121 dev->ibuffer,
122 sizeof(dev->ibuffer), &actual,
123 DIOLAN_USB_TIMEOUT);
124 /*
125 * Stop command processing if a previous command
126 * returned an error.
127 * Note that we still need to retrieve all messages.
128 */
129 if (ret < 0)
130 continue;
131 ret = tmpret;
132 if (ret == 0 && actual > 0) {
133 switch (dev->ibuffer[actual - 1]) {
134 case RESP_NACK:
135 /*
136 * Return ENXIO if NACK was received as
137 * response to the address phase,
138 * EIO otherwise
139 */
140 ret = i == 1 ? -ENXIO : -EIO;
141 break;
142 case RESP_TIMEOUT:
143 ret = -ETIMEDOUT;
144 break;
145 case RESP_OK:
146 /* strip off return code */
147 ret = actual - 1;
148 break;
149 default:
150 ret = -EIO;
151 break;
152 }
153 }
154 }
155 }
156 dev->olen = 0;
157 dev->ocount = 0;
158 return ret;
159}
160
161static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
162{
163 if (flush || dev->olen >= DIOLAN_FLUSH_LEN)
164 return diolan_usb_transfer(dev);
165 return 0;
166}
167
168/* Send command (no data) */
169static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
170{
171 dev->obuffer[dev->olen++] = command;
172 dev->ocount++;
173 return diolan_write_cmd(dev, flush);
174}
175
176/* Send command with one byte of data */
177static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
178 bool flush)
179{
180 dev->obuffer[dev->olen++] = command;
181 dev->obuffer[dev->olen++] = data;
182 dev->ocount++;
183 return diolan_write_cmd(dev, flush);
184}
185
186/* Send command with two bytes of data */
187static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
188 u8 d2, bool flush)
189{
190 dev->obuffer[dev->olen++] = command;
191 dev->obuffer[dev->olen++] = d1;
192 dev->obuffer[dev->olen++] = d2;
193 dev->ocount++;
194 return diolan_write_cmd(dev, flush);
195}
196
197/*
198 * Flush input queue.
199 * If we don't do this at startup and the controller has queued up
200 * messages which were not retrieved, it will stop responding
201 * at some point.
202 */
203static void diolan_flush_input(struct i2c_diolan_u2c *dev)
204{
205 int i;
206
207 for (i = 0; i < 10; i++) {
208 int actual = 0;
209 int ret;
210
211 ret = usb_bulk_msg(dev->usb_dev,
Martin Vogt4e4844c2013-11-24 15:57:23 +0100212 usb_rcvbulkpipe(dev->usb_dev, dev->ep_in),
Guenter Roeck335d7c52011-01-26 11:45:49 -0800213 dev->ibuffer, sizeof(dev->ibuffer), &actual,
214 DIOLAN_USB_TIMEOUT);
215 if (ret < 0 || actual == 0)
216 break;
217 }
218 if (i == 10)
219 dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
220}
221
222static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
223{
224 return diolan_usb_cmd(dev, CMD_I2C_START, false);
225}
226
227static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
228{
229 return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
230}
231
232static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
233{
234 return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
235}
236
237static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
238 u8 *byte)
239{
240 int ret;
241
242 ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
243 if (ret > 0)
244 *byte = dev->ibuffer[0];
245 else if (ret == 0)
246 ret = -EIO;
247
248 return ret;
249}
250
251static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
252{
253 return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
254}
255
256static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
257{
258 return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
259}
260
261/* Enable or disable clock synchronization (stretching) */
262static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
263{
264 return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
265}
266
267/* Set clock synchronization timeout in ms */
268static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
269{
270 int to_val = ms * 10;
271
272 return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
273 to_val & 0xff, (to_val >> 8) & 0xff, true);
274}
275
276static void diolan_fw_version(struct i2c_diolan_u2c *dev)
277{
278 int ret;
279
280 ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
281 if (ret >= 2)
282 dev_info(&dev->interface->dev,
283 "Diolan U2C firmware version %u.%u\n",
284 (unsigned int)dev->ibuffer[0],
285 (unsigned int)dev->ibuffer[1]);
286}
287
288static void diolan_get_serial(struct i2c_diolan_u2c *dev)
289{
290 int ret;
291 u32 serial;
292
293 ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
294 if (ret >= 4) {
295 serial = le32_to_cpu(*(u32 *)dev->ibuffer);
296 dev_info(&dev->interface->dev,
297 "Diolan U2C serial number %u\n", serial);
298 }
299}
300
301static int diolan_init(struct i2c_diolan_u2c *dev)
302{
303 int speed, ret;
304
305 if (frequency >= 200000) {
306 speed = U2C_I2C_SPEED_FAST;
307 frequency = U2C_I2C_FREQ_FAST;
308 } else if (frequency >= 100000 || frequency == 0) {
309 speed = U2C_I2C_SPEED_STD;
310 frequency = U2C_I2C_FREQ_STD;
311 } else {
312 speed = U2C_I2C_SPEED(frequency);
313 if (speed > U2C_I2C_SPEED_2KHZ)
314 speed = U2C_I2C_SPEED_2KHZ;
315 frequency = U2C_I2C_FREQ(speed);
316 }
317
318 dev_info(&dev->interface->dev,
319 "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
320 dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
321
322 diolan_flush_input(dev);
323 diolan_fw_version(dev);
324 diolan_get_serial(dev);
325
326 /* Set I2C speed */
327 ret = diolan_set_speed(dev, speed);
328 if (ret < 0)
329 return ret;
330
331 /* Configure I2C clock synchronization */
332 ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);
333 if (ret < 0)
334 return ret;
335
336 if (speed != U2C_I2C_SPEED_FAST)
337 ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);
338
339 return ret;
340}
341
342/* i2c layer */
343
344static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
345 int num)
346{
347 struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
348 struct i2c_msg *pmsg;
349 int i, j;
350 int ret, sret;
351
352 ret = diolan_i2c_start(dev);
353 if (ret < 0)
354 return ret;
355
356 for (i = 0; i < num; i++) {
357 pmsg = &msgs[i];
358 if (i) {
359 ret = diolan_i2c_repeated_start(dev);
360 if (ret < 0)
361 goto abort;
362 }
363 if (pmsg->flags & I2C_M_RD) {
364 ret =
365 diolan_i2c_put_byte_ack(dev, (pmsg->addr << 1) | 1);
366 if (ret < 0)
367 goto abort;
368 for (j = 0; j < pmsg->len; j++) {
369 u8 byte;
370 bool ack = j < pmsg->len - 1;
371
372 /*
373 * Don't send NACK if this is the first byte
374 * of a SMBUS_BLOCK message.
375 */
376 if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
377 ack = true;
378
379 ret = diolan_i2c_get_byte_ack(dev, ack, &byte);
380 if (ret < 0)
381 goto abort;
382 /*
383 * Adjust count if first received byte is length
384 */
385 if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
386 if (byte == 0
387 || byte > I2C_SMBUS_BLOCK_MAX) {
388 ret = -EPROTO;
389 goto abort;
390 }
391 pmsg->len += byte;
392 }
393 pmsg->buf[j] = byte;
394 }
395 } else {
396 ret = diolan_i2c_put_byte_ack(dev, pmsg->addr << 1);
397 if (ret < 0)
398 goto abort;
399 for (j = 0; j < pmsg->len; j++) {
400 ret = diolan_i2c_put_byte_ack(dev,
401 pmsg->buf[j]);
402 if (ret < 0)
403 goto abort;
404 }
405 }
406 }
Guenter Roeckab5625c2012-08-09 08:47:20 -0700407 ret = num;
Guenter Roeck335d7c52011-01-26 11:45:49 -0800408abort:
409 sret = diolan_i2c_stop(dev);
410 if (sret < 0 && ret >= 0)
411 ret = sret;
412 return ret;
413}
414
415/*
416 * Return list of supported functionality.
417 */
418static u32 diolan_usb_func(struct i2c_adapter *a)
419{
420 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
421 I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
422}
423
424static const struct i2c_algorithm diolan_usb_algorithm = {
425 .master_xfer = diolan_usb_xfer,
426 .functionality = diolan_usb_func,
427};
428
429/* device layer */
430
431static const struct usb_device_id diolan_u2c_table[] = {
432 { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
433 { }
434};
435
436MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
437
438static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
439{
440 usb_put_dev(dev->usb_dev);
441 kfree(dev);
442}
443
444static int diolan_u2c_probe(struct usb_interface *interface,
445 const struct usb_device_id *id)
446{
Martin Vogt4e4844c2013-11-24 15:57:23 +0100447 struct usb_host_interface *hostif = interface->cur_altsetting;
Guenter Roeck335d7c52011-01-26 11:45:49 -0800448 struct i2c_diolan_u2c *dev;
449 int ret;
450
Martin Vogt4e4844c2013-11-24 15:57:23 +0100451 if (hostif->desc.bInterfaceNumber != 0
452 || hostif->desc.bNumEndpoints < 2)
453 return -ENODEV;
454
Guenter Roeck335d7c52011-01-26 11:45:49 -0800455 /* allocate memory for our device state and initialize it */
456 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
457 if (dev == NULL) {
Guenter Roeck335d7c52011-01-26 11:45:49 -0800458 ret = -ENOMEM;
459 goto error;
460 }
Martin Vogt4e4844c2013-11-24 15:57:23 +0100461 dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
462 dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
Guenter Roeck335d7c52011-01-26 11:45:49 -0800463
464 dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
465 dev->interface = interface;
466
467 /* save our data pointer in this interface device */
468 usb_set_intfdata(interface, dev);
469
470 /* setup i2c adapter description */
471 dev->adapter.owner = THIS_MODULE;
472 dev->adapter.class = I2C_CLASS_HWMON;
473 dev->adapter.algo = &diolan_usb_algorithm;
474 i2c_set_adapdata(&dev->adapter, dev);
475 snprintf(dev->adapter.name, sizeof(dev->adapter.name),
476 DRIVER_NAME " at bus %03d device %03d",
477 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
478
479 dev->adapter.dev.parent = &dev->interface->dev;
480
481 /* initialize diolan i2c interface */
482 ret = diolan_init(dev);
483 if (ret < 0) {
484 dev_err(&interface->dev, "failed to initialize adapter\n");
485 goto error_free;
486 }
487
488 /* and finally attach to i2c layer */
489 ret = i2c_add_adapter(&dev->adapter);
490 if (ret < 0) {
491 dev_err(&interface->dev, "failed to add I2C adapter\n");
492 goto error_free;
493 }
494
495 dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
496
497 return 0;
498
499error_free:
500 usb_set_intfdata(interface, NULL);
501 diolan_u2c_free(dev);
502error:
503 return ret;
504}
505
506static void diolan_u2c_disconnect(struct usb_interface *interface)
507{
508 struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
509
510 i2c_del_adapter(&dev->adapter);
511 usb_set_intfdata(interface, NULL);
512 diolan_u2c_free(dev);
513
514 dev_dbg(&interface->dev, "disconnected\n");
515}
516
517static struct usb_driver diolan_u2c_driver = {
518 .name = DRIVER_NAME,
519 .probe = diolan_u2c_probe,
520 .disconnect = diolan_u2c_disconnect,
521 .id_table = diolan_u2c_table,
522};
523
Greg Kroah-Hartmanfe748482011-11-18 09:52:10 -0800524module_usb_driver(diolan_u2c_driver);
Guenter Roeck335d7c52011-01-26 11:45:49 -0800525
Guenter Roeck83a638d2012-07-24 14:13:56 +0200526MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
Guenter Roeck335d7c52011-01-26 11:45:49 -0800527MODULE_DESCRIPTION(DRIVER_NAME " driver");
528MODULE_LICENSE("GPL");