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 (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
28
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 */
82 struct i2c_diolan_u2c {
83 u8 obuffer[DIOLAN_OUTBUF_LEN]; /* output buffer */
84 u8 ibuffer[DIOLAN_INBUF_LEN]; /* input buffer */
85 int ep_in, ep_out; /* Endpoints */
86 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
93 static uint frequency = U2C_I2C_FREQ_STD; /* I2C clock frequency in Hz */
94
95 module_param(frequency, uint, S_IRUGO | S_IWUSR);
96 MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
97
98 /* usb layer */
99
100 /* Send command to device, and get response. */
diolan_usb_transfer(struct i2c_diolan_u2c * dev)101 static 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,
111 usb_sndbulkpipe(dev->usb_dev, dev->ep_out),
112 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,
120 dev->ep_in),
121 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
diolan_write_cmd(struct i2c_diolan_u2c * dev,bool flush)161 static 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) */
diolan_usb_cmd(struct i2c_diolan_u2c * dev,u8 command,bool flush)169 static 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 */
diolan_usb_cmd_data(struct i2c_diolan_u2c * dev,u8 command,u8 data,bool flush)177 static 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 */
diolan_usb_cmd_data2(struct i2c_diolan_u2c * dev,u8 command,u8 d1,u8 d2,bool flush)187 static 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 */
diolan_flush_input(struct i2c_diolan_u2c * dev)203 static 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,
212 usb_rcvbulkpipe(dev->usb_dev, dev->ep_in),
213 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
diolan_i2c_start(struct i2c_diolan_u2c * dev)222 static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
223 {
224 return diolan_usb_cmd(dev, CMD_I2C_START, false);
225 }
226
diolan_i2c_repeated_start(struct i2c_diolan_u2c * dev)227 static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
228 {
229 return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
230 }
231
diolan_i2c_stop(struct i2c_diolan_u2c * dev)232 static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
233 {
234 return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
235 }
236
diolan_i2c_get_byte_ack(struct i2c_diolan_u2c * dev,bool ack,u8 * byte)237 static 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
diolan_i2c_put_byte_ack(struct i2c_diolan_u2c * dev,u8 byte)251 static 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
diolan_set_speed(struct i2c_diolan_u2c * dev,u8 speed)256 static 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) */
diolan_set_clock_synch(struct i2c_diolan_u2c * dev,bool enable)262 static 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 */
diolan_set_clock_synch_timeout(struct i2c_diolan_u2c * dev,int ms)268 static 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
diolan_fw_version(struct i2c_diolan_u2c * dev)276 static 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
diolan_get_serial(struct i2c_diolan_u2c * dev)288 static 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
diolan_init(struct i2c_diolan_u2c * dev)301 static 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
diolan_usb_xfer(struct i2c_adapter * adapter,struct i2c_msg * msgs,int num)344 static 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 ret = diolan_i2c_put_byte_ack(dev,
364 i2c_8bit_addr_from_msg(pmsg));
365 if (ret < 0)
366 goto abort;
367 if (pmsg->flags & I2C_M_RD) {
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 for (j = 0; j < pmsg->len; j++) {
397 ret = diolan_i2c_put_byte_ack(dev,
398 pmsg->buf[j]);
399 if (ret < 0)
400 goto abort;
401 }
402 }
403 }
404 ret = num;
405 abort:
406 sret = diolan_i2c_stop(dev);
407 if (sret < 0 && ret >= 0)
408 ret = sret;
409 return ret;
410 }
411
412 /*
413 * Return list of supported functionality.
414 */
diolan_usb_func(struct i2c_adapter * a)415 static u32 diolan_usb_func(struct i2c_adapter *a)
416 {
417 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
418 I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
419 }
420
421 static const struct i2c_algorithm diolan_usb_algorithm = {
422 .master_xfer = diolan_usb_xfer,
423 .functionality = diolan_usb_func,
424 };
425
426 /* device layer */
427
428 static const struct usb_device_id diolan_u2c_table[] = {
429 { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
430 { }
431 };
432
433 MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
434
diolan_u2c_free(struct i2c_diolan_u2c * dev)435 static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
436 {
437 usb_put_dev(dev->usb_dev);
438 kfree(dev);
439 }
440
diolan_u2c_probe(struct usb_interface * interface,const struct usb_device_id * id)441 static int diolan_u2c_probe(struct usb_interface *interface,
442 const struct usb_device_id *id)
443 {
444 struct usb_host_interface *hostif = interface->cur_altsetting;
445 struct i2c_diolan_u2c *dev;
446 int ret;
447
448 if (hostif->desc.bInterfaceNumber != 0
449 || hostif->desc.bNumEndpoints < 2)
450 return -ENODEV;
451
452 /* allocate memory for our device state and initialize it */
453 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
454 if (dev == NULL) {
455 ret = -ENOMEM;
456 goto error;
457 }
458 dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
459 dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
460
461 dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
462 dev->interface = interface;
463
464 /* save our data pointer in this interface device */
465 usb_set_intfdata(interface, dev);
466
467 /* setup i2c adapter description */
468 dev->adapter.owner = THIS_MODULE;
469 dev->adapter.class = I2C_CLASS_HWMON;
470 dev->adapter.algo = &diolan_usb_algorithm;
471 i2c_set_adapdata(&dev->adapter, dev);
472 snprintf(dev->adapter.name, sizeof(dev->adapter.name),
473 DRIVER_NAME " at bus %03d device %03d",
474 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
475
476 dev->adapter.dev.parent = &dev->interface->dev;
477
478 /* initialize diolan i2c interface */
479 ret = diolan_init(dev);
480 if (ret < 0) {
481 dev_err(&interface->dev, "failed to initialize adapter\n");
482 goto error_free;
483 }
484
485 /* and finally attach to i2c layer */
486 ret = i2c_add_adapter(&dev->adapter);
487 if (ret < 0)
488 goto error_free;
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
diolan_u2c_disconnect(struct usb_interface * interface)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 <linux@roeck-us.net>");
522 MODULE_DESCRIPTION(DRIVER_NAME " driver");
523 MODULE_LICENSE("GPL");
524
