tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#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 */
84struct 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
94static uint frequency = U2C_I2C_FREQ_STD; /* I2C clock frequency in Hz */
95
96module_param(frequency, uint, S_IRUGO | S_IWUSR);
97MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
98
99/* usb layer */
100
101/* Send command to device, and get response. */
102static 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
162static 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) */
170static 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 */
178static 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 */
188static 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 */
204static 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
223static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
224{
225 return diolan_usb_cmd(dev, CMD_I2C_START, false);
226}
227
228static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
229{
230 return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
231}
232
233static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
234{
235 return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
236}
237
238static 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
252static 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
257static 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) */
263static 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 */
269static 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
277static 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
289static 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
302static 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
345static 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 }
408abort:
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{
447 struct i2c_diolan_u2c *dev;
448 int ret;
449
450 /* allocate memory for our device state and initialize it */
451 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
452 if (dev == NULL) {
453 dev_err(&interface->dev, "no memory for device state\n");
454 ret = -ENOMEM;
455 goto error;
456 }
457
458 dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
459 dev->interface = interface;
460
461 /* save our data pointer in this interface device */
462 usb_set_intfdata(interface, dev);
463
464 /* setup i2c adapter description */
465 dev->adapter.owner = THIS_MODULE;
466 dev->adapter.class = I2C_CLASS_HWMON;
467 dev->adapter.algo = &diolan_usb_algorithm;
468 i2c_set_adapdata(&dev->adapter, dev);
469 snprintf(dev->adapter.name, sizeof(dev->adapter.name),
470 DRIVER_NAME " at bus %03d device %03d",
471 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
472
473 dev->adapter.dev.parent = &dev->interface->dev;
474
475 /* initialize diolan i2c interface */
476 ret = diolan_init(dev);
477 if (ret < 0) {
478 dev_err(&interface->dev, "failed to initialize adapter\n");
479 goto error_free;
480 }
481
482 /* and finally attach to i2c layer */
483 ret = i2c_add_adapter(&dev->adapter);
484 if (ret < 0) {
485 dev_err(&interface->dev, "failed to add I2C adapter\n");
486 goto error_free;
487 }
488
489 dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
490
491 return 0;
492
493error_free:
494 usb_set_intfdata(interface, NULL);
495 diolan_u2c_free(dev);
496error:
497 return ret;
498}
499
500static void diolan_u2c_disconnect(struct usb_interface *interface)
501{
502 struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
503
504 i2c_del_adapter(&dev->adapter);
505 usb_set_intfdata(interface, NULL);
506 diolan_u2c_free(dev);
507
508 dev_dbg(&interface->dev, "disconnected\n");
509}
510
511static struct usb_driver diolan_u2c_driver = {
512 .name = DRIVER_NAME,
513 .probe = diolan_u2c_probe,
514 .disconnect = diolan_u2c_disconnect,
515 .id_table = diolan_u2c_table,
516};
517
518module_usb_driver(diolan_u2c_driver);
519
520MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
521MODULE_DESCRIPTION(DRIVER_NAME " driver");
522MODULE_LICENSE("GPL");