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i2c-diolan-u2c.c
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1 /*
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 ([email protected])
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 
28 #define DIOLAN_OUT_EP 0x02
29 #define DIOLAN_IN_EP 0x84
30 
31 /* commands via USB, must match command ids in the firmware */
32 #define CMD_I2C_READ 0x01
33 #define CMD_I2C_WRITE 0x02
34 #define CMD_I2C_SCAN 0x03 /* Returns list of detected devices */
35 #define CMD_I2C_RELEASE_SDA 0x04
36 #define CMD_I2C_RELEASE_SCL 0x05
37 #define CMD_I2C_DROP_SDA 0x06
38 #define CMD_I2C_DROP_SCL 0x07
39 #define CMD_I2C_READ_SDA 0x08
40 #define CMD_I2C_READ_SCL 0x09
41 #define CMD_GET_FW_VERSION 0x0a
42 #define CMD_GET_SERIAL 0x0b
43 #define CMD_I2C_START 0x0c
44 #define CMD_I2C_STOP 0x0d
45 #define CMD_I2C_REPEATED_START 0x0e
46 #define CMD_I2C_PUT_BYTE 0x0f
47 #define CMD_I2C_GET_BYTE 0x10
48 #define CMD_I2C_PUT_ACK 0x11
49 #define CMD_I2C_GET_ACK 0x12
50 #define CMD_I2C_PUT_BYTE_ACK 0x13
51 #define CMD_I2C_GET_BYTE_ACK 0x14
52 #define CMD_I2C_SET_SPEED 0x1b
53 #define CMD_I2C_GET_SPEED 0x1c
54 #define CMD_I2C_SET_CLK_SYNC 0x24
55 #define CMD_I2C_GET_CLK_SYNC 0x25
56 #define CMD_I2C_SET_CLK_SYNC_TO 0x26
57 #define CMD_I2C_GET_CLK_SYNC_TO 0x27
58 
59 #define RESP_OK 0x00
60 #define RESP_FAILED 0x01
61 #define RESP_BAD_MEMADDR 0x04
62 #define RESP_DATA_ERR 0x05
63 #define RESP_NOT_IMPLEMENTED 0x06
64 #define RESP_NACK 0x07
65 #define RESP_TIMEOUT 0x09
66 
67 #define U2C_I2C_SPEED_FAST 0 /* 400 kHz */
68 #define U2C_I2C_SPEED_STD 1 /* 100 kHz */
69 #define U2C_I2C_SPEED_2KHZ 242 /* 2 kHz, minimum speed */
70 #define U2C_I2C_SPEED(f) ((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)
71 
72 #define U2C_I2C_FREQ_FAST 400000
73 #define U2C_I2C_FREQ_STD 100000
74 #define U2C_I2C_FREQ(s) (1000000 / (2 * (s - 1) + 10))
75 
76 #define DIOLAN_USB_TIMEOUT 100 /* in ms */
77 #define DIOLAN_SYNC_TIMEOUT 20 /* in ms */
78 
79 #define DIOLAN_OUTBUF_LEN 128
80 #define DIOLAN_FLUSH_LEN (DIOLAN_OUTBUF_LEN - 4)
81 #define DIOLAN_INBUF_LEN 256 /* Maximum supported receive length */
82 
83 /* Structure to hold all of our device specific stuff */
84 struct i2c_diolan_u2c {
85  u8 obuffer[DIOLAN_OUTBUF_LEN]; /* output buffer */
86  u8 ibuffer[DIOLAN_INBUF_LEN]; /* input buffer */
87  struct usb_device *usb_dev; /* the usb device for this device */
88  struct usb_interface *interface;/* the interface for this device */
89  struct i2c_adapter adapter; /* i2c related things */
90  int olen; /* Output buffer length */
91  int ocount; /* Number of enqueued messages */
92 };
93 
94 static uint frequency = U2C_I2C_FREQ_STD; /* I2C clock frequency in Hz */
95 
96 module_param(frequency, uint, S_IRUGO | S_IWUSR);
97 MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
98 
99 /* usb layer */
100 
101 /* Send command to device, and get response. */
102 static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
103 {
104  int ret = 0;
105  int actual;
106  int i;
107 
108  if (!dev->olen || !dev->ocount)
109  return -EINVAL;
110 
111  ret = usb_bulk_msg(dev->usb_dev,
112  usb_sndbulkpipe(dev->usb_dev, DIOLAN_OUT_EP),
113  dev->obuffer, dev->olen, &actual,
114  DIOLAN_USB_TIMEOUT);
115  if (!ret) {
116  for (i = 0; i < dev->ocount; i++) {
117  int tmpret;
118 
119  tmpret = usb_bulk_msg(dev->usb_dev,
120  usb_rcvbulkpipe(dev->usb_dev,
121  DIOLAN_IN_EP),
122  dev->ibuffer,
123  sizeof(dev->ibuffer), &actual,
124  DIOLAN_USB_TIMEOUT);
125  /*
126  * Stop command processing if a previous command
127  * returned an error.
128  * Note that we still need to retrieve all messages.
129  */
130  if (ret < 0)
131  continue;
132  ret = tmpret;
133  if (ret == 0 && actual > 0) {
134  switch (dev->ibuffer[actual - 1]) {
135  case RESP_NACK:
136  /*
137  * Return ENXIO if NACK was received as
138  * response to the address phase,
139  * EIO otherwise
140  */
141  ret = i == 1 ? -ENXIO : -EIO;
142  break;
143  case RESP_TIMEOUT:
144  ret = -ETIMEDOUT;
145  break;
146  case RESP_OK:
147  /* strip off return code */
148  ret = actual - 1;
149  break;
150  default:
151  ret = -EIO;
152  break;
153  }
154  }
155  }
156  }
157  dev->olen = 0;
158  dev->ocount = 0;
159  return ret;
160 }
161 
162 static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
163 {
164  if (flush || dev->olen >= DIOLAN_FLUSH_LEN)
165  return diolan_usb_transfer(dev);
166  return 0;
167 }
168 
169 /* Send command (no data) */
170 static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
171 {
172  dev->obuffer[dev->olen++] = command;
173  dev->ocount++;
174  return diolan_write_cmd(dev, flush);
175 }
176 
177 /* Send command with one byte of data */
178 static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
179  bool flush)
180 {
181  dev->obuffer[dev->olen++] = command;
182  dev->obuffer[dev->olen++] = data;
183  dev->ocount++;
184  return diolan_write_cmd(dev, flush);
185 }
186 
187 /* Send command with two bytes of data */
188 static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
189  u8 d2, bool flush)
190 {
191  dev->obuffer[dev->olen++] = command;
192  dev->obuffer[dev->olen++] = d1;
193  dev->obuffer[dev->olen++] = d2;
194  dev->ocount++;
195  return diolan_write_cmd(dev, flush);
196 }
197 
198 /*
199  * Flush input queue.
200  * If we don't do this at startup and the controller has queued up
201  * messages which were not retrieved, it will stop responding
202  * at some point.
203  */
204 static void diolan_flush_input(struct i2c_diolan_u2c *dev)
205 {
206  int i;
207 
208  for (i = 0; i < 10; i++) {
209  int actual = 0;
210  int ret;
211 
212  ret = usb_bulk_msg(dev->usb_dev,
213  usb_rcvbulkpipe(dev->usb_dev, DIOLAN_IN_EP),
214  dev->ibuffer, sizeof(dev->ibuffer), &actual,
215  DIOLAN_USB_TIMEOUT);
216  if (ret < 0 || actual == 0)
217  break;
218  }
219  if (i == 10)
220  dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
221 }
222 
223 static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
224 {
225  return diolan_usb_cmd(dev, CMD_I2C_START, false);
226 }
227 
228 static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
229 {
230  return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
231 }
232 
233 static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
234 {
235  return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
236 }
237 
238 static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
239  u8 *byte)
240 {
241  int ret;
242 
243  ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
244  if (ret > 0)
245  *byte = dev->ibuffer[0];
246  else if (ret == 0)
247  ret = -EIO;
248 
249  return ret;
250 }
251 
252 static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
253 {
254  return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
255 }
256 
257 static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
258 {
259  return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
260 }
261 
262 /* Enable or disable clock synchronization (stretching) */
263 static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
264 {
265  return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
266 }
267 
268 /* Set clock synchronization timeout in ms */
269 static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
270 {
271  int to_val = ms * 10;
272 
273  return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
274  to_val & 0xff, (to_val >> 8) & 0xff, true);
275 }
276 
277 static void diolan_fw_version(struct i2c_diolan_u2c *dev)
278 {
279  int ret;
280 
281  ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
282  if (ret >= 2)
283  dev_info(&dev->interface->dev,
284  "Diolan U2C firmware version %u.%u\n",
285  (unsigned int)dev->ibuffer[0],
286  (unsigned int)dev->ibuffer[1]);
287 }
288 
289 static void diolan_get_serial(struct i2c_diolan_u2c *dev)
290 {
291  int ret;
292  u32 serial;
293 
294  ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
295  if (ret >= 4) {
296  serial = le32_to_cpu(*(u32 *)dev->ibuffer);
297  dev_info(&dev->interface->dev,
298  "Diolan U2C serial number %u\n", serial);
299  }
300 }
301 
302 static int diolan_init(struct i2c_diolan_u2c *dev)
303 {
304  int speed, ret;
305 
306  if (frequency >= 200000) {
307  speed = U2C_I2C_SPEED_FAST;
308  frequency = U2C_I2C_FREQ_FAST;
309  } else if (frequency >= 100000 || frequency == 0) {
310  speed = U2C_I2C_SPEED_STD;
311  frequency = U2C_I2C_FREQ_STD;
312  } else {
313  speed = U2C_I2C_SPEED(frequency);
314  if (speed > U2C_I2C_SPEED_2KHZ)
315  speed = U2C_I2C_SPEED_2KHZ;
316  frequency = U2C_I2C_FREQ(speed);
317  }
318 
319  dev_info(&dev->interface->dev,
320  "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
321  dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
322 
323  diolan_flush_input(dev);
324  diolan_fw_version(dev);
325  diolan_get_serial(dev);
326 
327  /* Set I2C speed */
328  ret = diolan_set_speed(dev, speed);
329  if (ret < 0)
330  return ret;
331 
332  /* Configure I2C clock synchronization */
333  ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);
334  if (ret < 0)
335  return ret;
336 
337  if (speed != U2C_I2C_SPEED_FAST)
338  ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);
339 
340  return ret;
341 }
342 
343 /* i2c layer */
344 
345 static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
346  int num)
347 {
348  struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
349  struct i2c_msg *pmsg;
350  int i, j;
351  int ret, sret;
352 
353  ret = diolan_i2c_start(dev);
354  if (ret < 0)
355  return ret;
356 
357  for (i = 0; i < num; i++) {
358  pmsg = &msgs[i];
359  if (i) {
360  ret = diolan_i2c_repeated_start(dev);
361  if (ret < 0)
362  goto abort;
363  }
364  if (pmsg->flags & I2C_M_RD) {
365  ret =
366  diolan_i2c_put_byte_ack(dev, (pmsg->addr << 1) | 1);
367  if (ret < 0)
368  goto abort;
369  for (j = 0; j < pmsg->len; j++) {
370  u8 byte;
371  bool ack = j < pmsg->len - 1;
372 
373  /*
374  * Don't send NACK if this is the first byte
375  * of a SMBUS_BLOCK message.
376  */
377  if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
378  ack = true;
379 
380  ret = diolan_i2c_get_byte_ack(dev, ack, &byte);
381  if (ret < 0)
382  goto abort;
383  /*
384  * Adjust count if first received byte is length
385  */
386  if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
387  if (byte == 0
388  || byte > I2C_SMBUS_BLOCK_MAX) {
389  ret = -EPROTO;
390  goto abort;
391  }
392  pmsg->len += byte;
393  }
394  pmsg->buf[j] = byte;
395  }
396  } else {
397  ret = diolan_i2c_put_byte_ack(dev, pmsg->addr << 1);
398  if (ret < 0)
399  goto abort;
400  for (j = 0; j < pmsg->len; j++) {
401  ret = diolan_i2c_put_byte_ack(dev,
402  pmsg->buf[j]);
403  if (ret < 0)
404  goto abort;
405  }
406  }
407  }
408  ret = num;
409 abort:
410  sret = diolan_i2c_stop(dev);
411  if (sret < 0 && ret >= 0)
412  ret = sret;
413  return ret;
414 }
415 
416 /*
417  * Return list of supported functionality.
418  */
419 static u32 diolan_usb_func(struct i2c_adapter *a)
420 {
421  return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
422  I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
423 }
424 
425 static const struct i2c_algorithm diolan_usb_algorithm = {
426  .master_xfer = diolan_usb_xfer,
427  .functionality = diolan_usb_func,
428 };
429 
430 /* device layer */
431 
432 static const struct usb_device_id diolan_u2c_table[] = {
433  { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
434  { }
435 };
436 
437 MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
438 
439 static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
440 {
441  usb_put_dev(dev->usb_dev);
442  kfree(dev);
443 }
444 
445 static int diolan_u2c_probe(struct usb_interface *interface,
446  const struct usb_device_id *id)
447 {
448  struct i2c_diolan_u2c *dev;
449  int ret;
450 
451  /* allocate memory for our device state and initialize it */
452  dev = kzalloc(sizeof(*dev), GFP_KERNEL);
453  if (dev == NULL) {
454  dev_err(&interface->dev, "no memory for device state\n");
455  ret = -ENOMEM;
456  goto error;
457  }
458 
459  dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
460  dev->interface = interface;
461 
462  /* save our data pointer in this interface device */
463  usb_set_intfdata(interface, dev);
464 
465  /* setup i2c adapter description */
466  dev->adapter.owner = THIS_MODULE;
467  dev->adapter.class = I2C_CLASS_HWMON;
468  dev->adapter.algo = &diolan_usb_algorithm;
469  i2c_set_adapdata(&dev->adapter, dev);
470  snprintf(dev->adapter.name, sizeof(dev->adapter.name),
471  DRIVER_NAME " at bus %03d device %03d",
472  dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
473 
474  dev->adapter.dev.parent = &dev->interface->dev;
475 
476  /* initialize diolan i2c interface */
477  ret = diolan_init(dev);
478  if (ret < 0) {
479  dev_err(&interface->dev, "failed to initialize adapter\n");
480  goto error_free;
481  }
482 
483  /* and finally attach to i2c layer */
484  ret = i2c_add_adapter(&dev->adapter);
485  if (ret < 0) {
486  dev_err(&interface->dev, "failed to add I2C adapter\n");
487  goto error_free;
488  }
489 
490  dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
491 
492  return 0;
493 
494 error_free:
495  usb_set_intfdata(interface, NULL);
496  diolan_u2c_free(dev);
497 error:
498  return ret;
499 }
500 
501 static void diolan_u2c_disconnect(struct usb_interface *interface)
502 {
503  struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
504 
505  i2c_del_adapter(&dev->adapter);
506  usb_set_intfdata(interface, NULL);
507  diolan_u2c_free(dev);
508 
509  dev_dbg(&interface->dev, "disconnected\n");
510 }
511 
512 static struct usb_driver diolan_u2c_driver = {
513  .name = DRIVER_NAME,
514  .probe = diolan_u2c_probe,
515  .disconnect = diolan_u2c_disconnect,
516  .id_table = diolan_u2c_table,
517 };
518 
519 module_usb_driver(diolan_u2c_driver);
520 
521 MODULE_AUTHOR("Guenter Roeck <[email protected]>");
522 MODULE_DESCRIPTION(DRIVER_NAME " driver");
523 MODULE_LICENSE("GPL");
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