xref: /linux/drivers/hwmon/ftsteutates.c (revision 24770983ccfec854d89da9d87ca5f2c9efc695fc)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Support for the FTS Systemmonitoring Chip "Teutates"
4  *
5  * Copyright (C) 2016 Fujitsu Technology Solutions GmbH,
6  *		  Thilo Cestonaro <thilo.cestonaro@ts.fujitsu.com>
7  */
8 #include <linux/err.h>
9 #include <linux/hwmon.h>
10 #include <linux/i2c.h>
11 #include <linux/init.h>
12 #include <linux/jiffies.h>
13 #include <linux/math.h>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
16 #include <linux/slab.h>
17 #include <linux/watchdog.h>
18 
19 #define FTS_DEVICE_ID_REG		0x0000
20 #define FTS_DEVICE_REVISION_REG		0x0001
21 #define FTS_DEVICE_STATUS_REG		0x0004
22 #define FTS_SATELLITE_STATUS_REG	0x0005
23 #define FTS_EVENT_STATUS_REG		0x0006
24 #define FTS_GLOBAL_CONTROL_REG		0x0007
25 
26 #define FTS_DEVICE_DETECT_REG_1		0x0C
27 #define FTS_DEVICE_DETECT_REG_2		0x0D
28 #define FTS_DEVICE_DETECT_REG_3		0x0E
29 
30 #define FTS_SENSOR_EVENT_REG		0x0010
31 
32 #define FTS_FAN_EVENT_REG		0x0014
33 #define FTS_FAN_PRESENT_REG		0x0015
34 
35 #define FTS_POWER_ON_TIME_COUNTER_A	0x007A
36 #define FTS_POWER_ON_TIME_COUNTER_B	0x007B
37 #define FTS_POWER_ON_TIME_COUNTER_C	0x007C
38 
39 #define FTS_PAGE_SELECT_REG		0x007F
40 
41 #define FTS_WATCHDOG_TIME_PRESET	0x000B
42 #define FTS_WATCHDOG_CONTROL		0x5081
43 
44 #define FTS_NO_FAN_SENSORS		0x08
45 #define FTS_NO_TEMP_SENSORS		0x10
46 #define FTS_NO_VOLT_SENSORS		0x04
47 
48 #define FTS_FAN_SOURCE_INVALID		0xff
49 
50 static const unsigned short normal_i2c[] = { 0x73, I2C_CLIENT_END };
51 
52 static const struct i2c_device_id fts_id[] = {
53 	{ "ftsteutates" },
54 	{ }
55 };
56 MODULE_DEVICE_TABLE(i2c, fts_id);
57 
58 enum WATCHDOG_RESOLUTION {
59 	seconds = 1,
60 	minutes = 60
61 };
62 
63 struct fts_data {
64 	struct i2c_client *client;
65 	/* update sensor data lock */
66 	struct mutex update_lock;
67 	/* read/write register lock */
68 	struct mutex access_lock;
69 	unsigned long last_updated; /* in jiffies */
70 	struct watchdog_device wdd;
71 	enum WATCHDOG_RESOLUTION resolution;
72 	bool valid; /* false until following fields are valid */
73 
74 	u8 volt[FTS_NO_VOLT_SENSORS];
75 
76 	u8 temp_input[FTS_NO_TEMP_SENSORS];
77 	u8 temp_alarm;
78 
79 	u8 fan_present;
80 	u8 fan_input[FTS_NO_FAN_SENSORS]; /* in rps */
81 	u8 fan_source[FTS_NO_FAN_SENSORS];
82 	u8 fan_alarm;
83 };
84 
85 #define FTS_REG_FAN_INPUT(idx) ((idx) + 0x20)
86 #define FTS_REG_FAN_SOURCE(idx) ((idx) + 0x30)
87 #define FTS_REG_FAN_CONTROL(idx) (((idx) << 16) + 0x4881)
88 
89 #define FTS_REG_TEMP_INPUT(idx) ((idx) + 0x40)
90 #define FTS_REG_TEMP_CONTROL(idx) (((idx) << 16) + 0x0681)
91 
92 #define FTS_REG_VOLT(idx) ((idx) + 0x18)
93 
94 /*****************************************************************************/
95 /* I2C Helper functions							     */
96 /*****************************************************************************/
fts_read_byte(struct i2c_client * client,unsigned short reg)97 static int fts_read_byte(struct i2c_client *client, unsigned short reg)
98 {
99 	int ret;
100 	unsigned char page = reg >> 8;
101 	struct fts_data *data = dev_get_drvdata(&client->dev);
102 
103 	mutex_lock(&data->access_lock);
104 
105 	dev_dbg(&client->dev, "page select - page: 0x%.02x\n", page);
106 	ret = i2c_smbus_write_byte_data(client, FTS_PAGE_SELECT_REG, page);
107 	if (ret < 0)
108 		goto error;
109 
110 	reg &= 0xFF;
111 	ret = i2c_smbus_read_byte_data(client, reg);
112 	dev_dbg(&client->dev, "read - reg: 0x%.02x: val: 0x%.02x\n", reg, ret);
113 
114 error:
115 	mutex_unlock(&data->access_lock);
116 	return ret;
117 }
118 
fts_write_byte(struct i2c_client * client,unsigned short reg,unsigned char value)119 static int fts_write_byte(struct i2c_client *client, unsigned short reg,
120 			  unsigned char value)
121 {
122 	int ret;
123 	unsigned char page = reg >> 8;
124 	struct fts_data *data = dev_get_drvdata(&client->dev);
125 
126 	mutex_lock(&data->access_lock);
127 
128 	dev_dbg(&client->dev, "page select - page: 0x%.02x\n", page);
129 	ret = i2c_smbus_write_byte_data(client, FTS_PAGE_SELECT_REG, page);
130 	if (ret < 0)
131 		goto error;
132 
133 	reg &= 0xFF;
134 	dev_dbg(&client->dev,
135 		"write - reg: 0x%.02x: val: 0x%.02x\n", reg, value);
136 	ret = i2c_smbus_write_byte_data(client, reg, value);
137 
138 error:
139 	mutex_unlock(&data->access_lock);
140 	return ret;
141 }
142 
143 /*****************************************************************************/
144 /* Data Updater Helper function						     */
145 /*****************************************************************************/
fts_update_device(struct fts_data * data)146 static int fts_update_device(struct fts_data *data)
147 {
148 	int i;
149 	int err = 0;
150 
151 	mutex_lock(&data->update_lock);
152 	if (!time_after(jiffies, data->last_updated + 2 * HZ) && data->valid)
153 		goto exit;
154 
155 	err = fts_read_byte(data->client, FTS_DEVICE_STATUS_REG);
156 	if (err < 0)
157 		goto exit;
158 
159 	data->valid = !!(err & 0x02); /* Data not ready yet */
160 	if (unlikely(!data->valid)) {
161 		err = -EAGAIN;
162 		goto exit;
163 	}
164 
165 	err = fts_read_byte(data->client, FTS_FAN_PRESENT_REG);
166 	if (err < 0)
167 		goto exit;
168 	data->fan_present = err;
169 
170 	err = fts_read_byte(data->client, FTS_FAN_EVENT_REG);
171 	if (err < 0)
172 		goto exit;
173 	data->fan_alarm = err;
174 
175 	for (i = 0; i < FTS_NO_FAN_SENSORS; i++) {
176 		if (data->fan_present & BIT(i)) {
177 			err = fts_read_byte(data->client, FTS_REG_FAN_INPUT(i));
178 			if (err < 0)
179 				goto exit;
180 			data->fan_input[i] = err;
181 
182 			err = fts_read_byte(data->client,
183 					    FTS_REG_FAN_SOURCE(i));
184 			if (err < 0)
185 				goto exit;
186 			data->fan_source[i] = err;
187 		} else {
188 			data->fan_input[i] = 0;
189 			data->fan_source[i] = FTS_FAN_SOURCE_INVALID;
190 		}
191 	}
192 
193 	err = fts_read_byte(data->client, FTS_SENSOR_EVENT_REG);
194 	if (err < 0)
195 		goto exit;
196 	data->temp_alarm = err;
197 
198 	for (i = 0; i < FTS_NO_TEMP_SENSORS; i++) {
199 		err = fts_read_byte(data->client, FTS_REG_TEMP_INPUT(i));
200 		if (err < 0)
201 			goto exit;
202 		data->temp_input[i] = err;
203 	}
204 
205 	for (i = 0; i < FTS_NO_VOLT_SENSORS; i++) {
206 		err = fts_read_byte(data->client, FTS_REG_VOLT(i));
207 		if (err < 0)
208 			goto exit;
209 		data->volt[i] = err;
210 	}
211 	data->last_updated = jiffies;
212 	err = 0;
213 exit:
214 	mutex_unlock(&data->update_lock);
215 	return err;
216 }
217 
218 /*****************************************************************************/
219 /* Watchdog functions							     */
220 /*****************************************************************************/
fts_wd_set_resolution(struct fts_data * data,enum WATCHDOG_RESOLUTION resolution)221 static int fts_wd_set_resolution(struct fts_data *data,
222 				 enum WATCHDOG_RESOLUTION resolution)
223 {
224 	int ret;
225 
226 	if (data->resolution == resolution)
227 		return 0;
228 
229 	ret = fts_read_byte(data->client, FTS_WATCHDOG_CONTROL);
230 	if (ret < 0)
231 		return ret;
232 
233 	if ((resolution == seconds && ret & BIT(1)) ||
234 	    (resolution == minutes && (ret & BIT(1)) == 0)) {
235 		data->resolution = resolution;
236 		return 0;
237 	}
238 
239 	if (resolution == seconds)
240 		ret |= BIT(1);
241 	else
242 		ret &= ~BIT(1);
243 
244 	ret = fts_write_byte(data->client, FTS_WATCHDOG_CONTROL, ret);
245 	if (ret < 0)
246 		return ret;
247 
248 	data->resolution = resolution;
249 	return ret;
250 }
251 
fts_wd_set_timeout(struct watchdog_device * wdd,unsigned int timeout)252 static int fts_wd_set_timeout(struct watchdog_device *wdd, unsigned int timeout)
253 {
254 	struct fts_data *data;
255 	enum WATCHDOG_RESOLUTION resolution = seconds;
256 	int ret;
257 
258 	data = watchdog_get_drvdata(wdd);
259 	/* switch watchdog resolution to minutes if timeout does not fit
260 	 * into a byte
261 	 */
262 	if (timeout > 0xFF) {
263 		timeout = DIV_ROUND_UP(timeout, 60) * 60;
264 		resolution = minutes;
265 	}
266 
267 	ret = fts_wd_set_resolution(data, resolution);
268 	if (ret < 0)
269 		return ret;
270 
271 	wdd->timeout = timeout;
272 	return 0;
273 }
274 
fts_wd_start(struct watchdog_device * wdd)275 static int fts_wd_start(struct watchdog_device *wdd)
276 {
277 	struct fts_data *data = watchdog_get_drvdata(wdd);
278 
279 	return fts_write_byte(data->client, FTS_WATCHDOG_TIME_PRESET,
280 			      wdd->timeout / (u8)data->resolution);
281 }
282 
fts_wd_stop(struct watchdog_device * wdd)283 static int fts_wd_stop(struct watchdog_device *wdd)
284 {
285 	struct fts_data *data;
286 
287 	data = watchdog_get_drvdata(wdd);
288 	return fts_write_byte(data->client, FTS_WATCHDOG_TIME_PRESET, 0);
289 }
290 
291 static const struct watchdog_info fts_wd_info = {
292 	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
293 	.identity = "FTS Teutates Hardware Watchdog",
294 };
295 
296 static const struct watchdog_ops fts_wd_ops = {
297 	.owner = THIS_MODULE,
298 	.start = fts_wd_start,
299 	.stop = fts_wd_stop,
300 	.set_timeout = fts_wd_set_timeout,
301 };
302 
fts_watchdog_init(struct fts_data * data)303 static int fts_watchdog_init(struct fts_data *data)
304 {
305 	int timeout, ret;
306 
307 	watchdog_set_drvdata(&data->wdd, data);
308 
309 	timeout = fts_read_byte(data->client, FTS_WATCHDOG_TIME_PRESET);
310 	if (timeout < 0)
311 		return timeout;
312 
313 	/* watchdog not running, set timeout to a default of 60 sec. */
314 	if (timeout == 0) {
315 		ret = fts_wd_set_resolution(data, seconds);
316 		if (ret < 0)
317 			return ret;
318 		data->wdd.timeout = 60;
319 	} else {
320 		ret = fts_read_byte(data->client, FTS_WATCHDOG_CONTROL);
321 		if (ret < 0)
322 			return ret;
323 
324 		data->resolution = ret & BIT(1) ? seconds : minutes;
325 		data->wdd.timeout = timeout * (u8)data->resolution;
326 		set_bit(WDOG_HW_RUNNING, &data->wdd.status);
327 	}
328 
329 	/* Register our watchdog part */
330 	data->wdd.info = &fts_wd_info;
331 	data->wdd.ops = &fts_wd_ops;
332 	data->wdd.parent = &data->client->dev;
333 	data->wdd.min_timeout = 1;
334 
335 	/* max timeout 255 minutes. */
336 	data->wdd.max_hw_heartbeat_ms = 0xFF * 60 * MSEC_PER_SEC;
337 
338 	return devm_watchdog_register_device(&data->client->dev, &data->wdd);
339 }
340 
fts_is_visible(const void * devdata,enum hwmon_sensor_types type,u32 attr,int channel)341 static umode_t fts_is_visible(const void *devdata, enum hwmon_sensor_types type, u32 attr,
342 			      int channel)
343 {
344 	switch (type) {
345 	case hwmon_temp:
346 		switch (attr) {
347 		case hwmon_temp_input:
348 		case hwmon_temp_fault:
349 			return 0444;
350 		case hwmon_temp_alarm:
351 			return 0644;
352 		default:
353 			break;
354 		}
355 		break;
356 	case hwmon_fan:
357 		switch (attr) {
358 		case hwmon_fan_input:
359 		case hwmon_fan_fault:
360 			return 0444;
361 		case hwmon_fan_alarm:
362 			return 0644;
363 		default:
364 			break;
365 		}
366 		break;
367 	case hwmon_pwm:
368 	case hwmon_in:
369 		return 0444;
370 	default:
371 		break;
372 	}
373 
374 	return 0;
375 }
376 
fts_read(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long * val)377 static int fts_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
378 		    long *val)
379 {
380 	struct fts_data *data = dev_get_drvdata(dev);
381 	int ret = fts_update_device(data);
382 
383 	if (ret < 0)
384 		return ret;
385 
386 	switch (type) {
387 	case hwmon_temp:
388 		switch (attr) {
389 		case hwmon_temp_input:
390 			*val = (data->temp_input[channel] - 64) * 1000;
391 
392 			return 0;
393 		case hwmon_temp_alarm:
394 			*val = !!(data->temp_alarm & BIT(channel));
395 
396 			return 0;
397 		case hwmon_temp_fault:
398 			/* 00h Temperature = Sensor Error */;
399 			*val = (data->temp_input[channel] == 0);
400 
401 			return 0;
402 		default:
403 			break;
404 		}
405 		break;
406 	case hwmon_fan:
407 		switch (attr) {
408 		case hwmon_fan_input:
409 			*val = data->fan_input[channel] * 60;
410 
411 			return 0;
412 		case hwmon_fan_alarm:
413 			*val = !!(data->fan_alarm & BIT(channel));
414 
415 			return 0;
416 		case hwmon_fan_fault:
417 			*val = !(data->fan_present & BIT(channel));
418 
419 			return 0;
420 		default:
421 			break;
422 		}
423 		break;
424 	case hwmon_pwm:
425 		switch (attr) {
426 		case hwmon_pwm_auto_channels_temp: {
427 			u8 fan_source = data->fan_source[channel];
428 
429 			if (fan_source == FTS_FAN_SOURCE_INVALID || fan_source >= BITS_PER_LONG)
430 				*val = 0;
431 			else
432 				*val = BIT(fan_source);
433 
434 			return 0;
435 		}
436 		default:
437 			break;
438 		}
439 		break;
440 	case hwmon_in:
441 		switch (attr) {
442 		case hwmon_in_input:
443 			*val = DIV_ROUND_CLOSEST(data->volt[channel] * 3300, 255);
444 
445 			return 0;
446 		default:
447 			break;
448 		}
449 		break;
450 	default:
451 		break;
452 	}
453 
454 	return -EOPNOTSUPP;
455 }
456 
fts_write(struct device * dev,enum hwmon_sensor_types type,u32 attr,int channel,long val)457 static int fts_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel,
458 		     long val)
459 {
460 	struct fts_data *data = dev_get_drvdata(dev);
461 	int ret = fts_update_device(data);
462 
463 	if (ret < 0)
464 		return ret;
465 
466 	switch (type) {
467 	case hwmon_temp:
468 		switch (attr) {
469 		case hwmon_temp_alarm:
470 			if (val)
471 				return -EINVAL;
472 
473 			mutex_lock(&data->update_lock);
474 			ret = fts_read_byte(data->client, FTS_REG_TEMP_CONTROL(channel));
475 			if (ret >= 0)
476 				ret = fts_write_byte(data->client, FTS_REG_TEMP_CONTROL(channel),
477 						     ret | 0x1);
478 			if (ret >= 0)
479 				data->valid = false;
480 
481 			mutex_unlock(&data->update_lock);
482 			if (ret < 0)
483 				return ret;
484 
485 			return 0;
486 		default:
487 			break;
488 		}
489 		break;
490 	case hwmon_fan:
491 		switch (attr) {
492 		case hwmon_fan_alarm:
493 			if (val)
494 				return -EINVAL;
495 
496 			mutex_lock(&data->update_lock);
497 			ret = fts_read_byte(data->client, FTS_REG_FAN_CONTROL(channel));
498 			if (ret >= 0)
499 				ret = fts_write_byte(data->client, FTS_REG_FAN_CONTROL(channel),
500 						     ret | 0x1);
501 			if (ret >= 0)
502 				data->valid = false;
503 
504 			mutex_unlock(&data->update_lock);
505 			if (ret < 0)
506 				return ret;
507 
508 			return 0;
509 		default:
510 			break;
511 		}
512 		break;
513 	default:
514 		break;
515 	}
516 
517 	return -EOPNOTSUPP;
518 }
519 
520 static const struct hwmon_ops fts_ops = {
521 	.is_visible = fts_is_visible,
522 	.read = fts_read,
523 	.write = fts_write,
524 };
525 
526 static const struct hwmon_channel_info * const fts_info[] = {
527 	HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
528 	HWMON_CHANNEL_INFO(temp,
529 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
530 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
531 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
532 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
533 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
534 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
535 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
536 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
537 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
538 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
539 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
540 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
541 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
542 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
543 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT,
544 			   HWMON_T_INPUT | HWMON_T_ALARM | HWMON_T_FAULT
545 			   ),
546 	HWMON_CHANNEL_INFO(fan,
547 			   HWMON_F_INPUT | HWMON_F_ALARM | HWMON_F_FAULT,
548 			   HWMON_F_INPUT | HWMON_F_ALARM | HWMON_F_FAULT,
549 			   HWMON_F_INPUT | HWMON_F_ALARM | HWMON_F_FAULT,
550 			   HWMON_F_INPUT | HWMON_F_ALARM | HWMON_F_FAULT,
551 			   HWMON_F_INPUT | HWMON_F_ALARM | HWMON_F_FAULT,
552 			   HWMON_F_INPUT | HWMON_F_ALARM | HWMON_F_FAULT,
553 			   HWMON_F_INPUT | HWMON_F_ALARM | HWMON_F_FAULT,
554 			   HWMON_F_INPUT | HWMON_F_ALARM | HWMON_F_FAULT
555 			   ),
556 	HWMON_CHANNEL_INFO(pwm,
557 			   HWMON_PWM_AUTO_CHANNELS_TEMP,
558 			   HWMON_PWM_AUTO_CHANNELS_TEMP,
559 			   HWMON_PWM_AUTO_CHANNELS_TEMP,
560 			   HWMON_PWM_AUTO_CHANNELS_TEMP,
561 			   HWMON_PWM_AUTO_CHANNELS_TEMP,
562 			   HWMON_PWM_AUTO_CHANNELS_TEMP,
563 			   HWMON_PWM_AUTO_CHANNELS_TEMP,
564 			   HWMON_PWM_AUTO_CHANNELS_TEMP
565 			   ),
566 	HWMON_CHANNEL_INFO(in,
567 			   HWMON_I_INPUT,
568 			   HWMON_I_INPUT,
569 			   HWMON_I_INPUT,
570 			   HWMON_I_INPUT
571 			   ),
572 	NULL
573 };
574 
575 static const struct hwmon_chip_info fts_chip_info = {
576 	.ops = &fts_ops,
577 	.info = fts_info,
578 };
579 
580 /*****************************************************************************/
581 /* Module initialization / remove functions				     */
582 /*****************************************************************************/
fts_detect(struct i2c_client * client,struct i2c_board_info * info)583 static int fts_detect(struct i2c_client *client,
584 		      struct i2c_board_info *info)
585 {
586 	int val;
587 
588 	/* detection works with revision greater or equal to 0x2b */
589 	val = i2c_smbus_read_byte_data(client, FTS_DEVICE_REVISION_REG);
590 	if (val < 0x2b)
591 		return -ENODEV;
592 
593 	/* Device Detect Regs must have 0x17 0x34 and 0x54 */
594 	val = i2c_smbus_read_byte_data(client, FTS_DEVICE_DETECT_REG_1);
595 	if (val != 0x17)
596 		return -ENODEV;
597 
598 	val = i2c_smbus_read_byte_data(client, FTS_DEVICE_DETECT_REG_2);
599 	if (val != 0x34)
600 		return -ENODEV;
601 
602 	val = i2c_smbus_read_byte_data(client, FTS_DEVICE_DETECT_REG_3);
603 	if (val != 0x54)
604 		return -ENODEV;
605 
606 	/*
607 	 * 0x10 == Baseboard Management Controller, 0x01 == Teutates
608 	 * Device ID Reg needs to be 0x11
609 	 */
610 	val = i2c_smbus_read_byte_data(client, FTS_DEVICE_ID_REG);
611 	if (val != 0x11)
612 		return -ENODEV;
613 
614 	strscpy(info->type, fts_id[0].name, I2C_NAME_SIZE);
615 	info->flags = 0;
616 	return 0;
617 }
618 
fts_probe(struct i2c_client * client)619 static int fts_probe(struct i2c_client *client)
620 {
621 	u8 revision;
622 	struct fts_data *data;
623 	int err;
624 	s8 deviceid;
625 	struct device *hwmon_dev;
626 
627 	if (client->addr != 0x73)
628 		return -ENODEV;
629 
630 	/* Baseboard Management Controller check */
631 	deviceid = i2c_smbus_read_byte_data(client, FTS_DEVICE_ID_REG);
632 	if (deviceid > 0 && (deviceid & 0xF0) == 0x10) {
633 		switch (deviceid & 0x0F) {
634 		case 0x01:
635 			break;
636 		default:
637 			dev_dbg(&client->dev,
638 				"No Baseboard Management Controller\n");
639 			return -ENODEV;
640 		}
641 	} else {
642 		dev_dbg(&client->dev, "No fujitsu board\n");
643 		return -ENODEV;
644 	}
645 
646 	data = devm_kzalloc(&client->dev, sizeof(struct fts_data),
647 			    GFP_KERNEL);
648 	if (!data)
649 		return -ENOMEM;
650 
651 	mutex_init(&data->update_lock);
652 	mutex_init(&data->access_lock);
653 	data->client = client;
654 	dev_set_drvdata(&client->dev, data);
655 
656 	err = i2c_smbus_read_byte_data(client, FTS_DEVICE_REVISION_REG);
657 	if (err < 0)
658 		return err;
659 	revision = err;
660 
661 	hwmon_dev = devm_hwmon_device_register_with_info(&client->dev, "ftsteutates", data,
662 							 &fts_chip_info, NULL);
663 	if (IS_ERR(hwmon_dev))
664 		return PTR_ERR(hwmon_dev);
665 
666 	err = fts_watchdog_init(data);
667 	if (err)
668 		return err;
669 
670 	dev_info(&client->dev, "Detected FTS Teutates chip, revision: %d.%d\n",
671 		 (revision & 0xF0) >> 4, revision & 0x0F);
672 	return 0;
673 }
674 
675 /*****************************************************************************/
676 /* Module Details							     */
677 /*****************************************************************************/
678 static struct i2c_driver fts_driver = {
679 	.class = I2C_CLASS_HWMON,
680 	.driver = {
681 		.name = "ftsteutates",
682 	},
683 	.id_table = fts_id,
684 	.probe = fts_probe,
685 	.detect = fts_detect,
686 	.address_list = normal_i2c,
687 };
688 
689 module_i2c_driver(fts_driver);
690 
691 MODULE_AUTHOR("Thilo Cestonaro <thilo.cestonaro@ts.fujitsu.com>");
692 MODULE_DESCRIPTION("FTS Teutates driver");
693 MODULE_LICENSE("GPL");
694