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Viewing changes to drivers/i2c/busses/i2c-diolan-u2c.c

  • Committer: Bazaar Package Importer
  • Author(s): Paolo Pisati
  • Date: 2011-06-29 15:23:51 UTC
  • mfrom: (26.1.1 natty-proposed)
  • Revision ID: james.westby@ubuntu.com-20110629152351-xs96tm303d95rpbk
Tags: 3.0.0-1200.2
* Rebased against 3.0.0-6.7
* BSP from TI based on 3.0.0

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Lines of Context:
drivers/i2c/busses/i2c-diolan-u2c.c
 
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 */
 
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
abort:
 
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
 */
 
418
static 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
 
 
424
static const struct i2c_algorithm diolan_usb_algorithm = {
 
425
        .master_xfer = diolan_usb_xfer,
 
426
        .functionality = diolan_usb_func,
 
427
};
 
428
 
 
429
/* device layer */
 
430
 
 
431
static const struct usb_device_id diolan_u2c_table[] = {
 
432
        { USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
 
433
        { }
 
434
};
 
435
 
 
436
MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
 
437
 
 
438
static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
 
439
{
 
440
        usb_put_dev(dev->usb_dev);
 
441
        kfree(dev);
 
442
}
 
443
 
 
444
static 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
 
 
493
error_free:
 
494
        usb_set_intfdata(interface, NULL);
 
495
        diolan_u2c_free(dev);
 
496
error:
 
497
        return ret;
 
498
}
 
499
 
 
500
static 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
 
 
511
static 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
 
 
518
static int __init diolan_u2c_init(void)
 
519
{
 
520
        /* register this driver with the USB subsystem */
 
521
        return usb_register(&diolan_u2c_driver);
 
522
}
 
523
 
 
524
static void __exit diolan_u2c_exit(void)
 
525
{
 
526
        /* deregister this driver with the USB subsystem */
 
527
        usb_deregister(&diolan_u2c_driver);
 
528
}
 
529
 
 
530
module_init(diolan_u2c_init);
 
531
module_exit(diolan_u2c_exit);
 
532
 
 
533
MODULE_AUTHOR("Guenter Roeck <guenter.roeck@ericsson.com>");
 
534
MODULE_DESCRIPTION(DRIVER_NAME " driver");
 
535
MODULE_LICENSE("GPL");