Loading...
Note: File does not exist in v5.9.
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Hardware monitoring driver for EMC2305 fan controller
4 *
5 * Copyright (C) 2022 Nvidia Technologies Ltd.
6 */
7
8#include <linux/err.h>
9#include <linux/hwmon.h>
10#include <linux/i2c.h>
11#include <linux/module.h>
12#include <linux/platform_data/emc2305.h>
13#include <linux/thermal.h>
14
15static const unsigned short
16emc2305_normal_i2c[] = { 0x27, 0x2c, 0x2d, 0x2e, 0x2f, 0x4c, 0x4d, I2C_CLIENT_END };
17
18#define EMC2305_REG_DRIVE_FAIL_STATUS 0x27
19#define EMC2305_REG_VENDOR 0xfe
20#define EMC2305_FAN_MAX 0xff
21#define EMC2305_FAN_MIN 0x00
22#define EMC2305_FAN_MAX_STATE 10
23#define EMC2305_DEVICE 0x34
24#define EMC2305_VENDOR 0x5d
25#define EMC2305_REG_PRODUCT_ID 0xfd
26#define EMC2305_TACH_REGS_UNUSE_BITS 3
27#define EMC2305_TACH_CNT_MULTIPLIER 0x02
28#define EMC2305_TACH_RANGE_MIN 480
29
30#define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) \
31 DIV_ROUND_CLOSEST((duty) * (max_state), (pwm_max))
32#define EMC2305_PWM_STATE2DUTY(state, max_state, pwm_max) \
33 DIV_ROUND_CLOSEST((state) * (pwm_max), (max_state))
34
35/*
36 * Factor by equations [2] and [3] from data sheet; valid for fans where the number of edges
37 * equal (poles * 2 + 1).
38 */
39#define EMC2305_RPM_FACTOR 3932160
40
41#define EMC2305_REG_FAN_DRIVE(n) (0x30 + 0x10 * (n))
42#define EMC2305_REG_FAN_MIN_DRIVE(n) (0x38 + 0x10 * (n))
43#define EMC2305_REG_FAN_TACH(n) (0x3e + 0x10 * (n))
44
45enum emc230x_product_id {
46 EMC2305 = 0x34,
47 EMC2303 = 0x35,
48 EMC2302 = 0x36,
49 EMC2301 = 0x37,
50};
51
52static const struct i2c_device_id emc2305_ids[] = {
53 { "emc2305", 0 },
54 { "emc2303", 0 },
55 { "emc2302", 0 },
56 { "emc2301", 0 },
57 { }
58};
59MODULE_DEVICE_TABLE(i2c, emc2305_ids);
60
61/**
62 * @cdev: cooling device;
63 * @curr_state: cooling current state;
64 * @last_hwmon_state: last cooling state updated by hwmon subsystem;
65 * @last_thermal_state: last cooling state updated by thermal subsystem;
66 *
67 * The 'last_hwmon_state' and 'last_thermal_state' fields are provided to support fan low limit
68 * speed feature. The purpose of this feature is to provides ability to limit fan speed
69 * according to some system wise considerations, like absence of some replaceable units (PSU or
70 * line cards), high system ambient temperature, unreliable transceivers temperature sensing or
71 * some other factors which indirectly impacts system's airflow
72 * Fan low limit feature is supported through 'hwmon' interface: 'hwmon' 'pwm' attribute is
73 * used for setting low limit for fan speed in case 'thermal' subsystem is configured in
74 * kernel. In this case setting fan speed through 'hwmon' will never let the 'thermal'
75 * subsystem to select a lower duty cycle than the duty cycle selected with the 'pwm'
76 * attribute.
77 * From other side, fan speed is to be updated in hardware through 'pwm' only in case the
78 * requested fan speed is above last speed set by 'thermal' subsystem, otherwise requested fan
79 * speed will be just stored with no PWM update.
80 */
81struct emc2305_cdev_data {
82 struct thermal_cooling_device *cdev;
83 unsigned int cur_state;
84 unsigned long last_hwmon_state;
85 unsigned long last_thermal_state;
86};
87
88/**
89 * @client: i2c client;
90 * @hwmon_dev: hwmon device;
91 * @max_state: maximum cooling state of the cooling device;
92 * @pwm_num: number of PWM channels;
93 * @pwm_separate: separate PWM settings for every channel;
94 * @pwm_min: array of minimum PWM per channel;
95 * @cdev_data: array of cooling devices data;
96 */
97struct emc2305_data {
98 struct i2c_client *client;
99 struct device *hwmon_dev;
100 u8 max_state;
101 u8 pwm_num;
102 bool pwm_separate;
103 u8 pwm_min[EMC2305_PWM_MAX];
104 struct emc2305_cdev_data cdev_data[EMC2305_PWM_MAX];
105};
106
107static char *emc2305_fan_name[] = {
108 "emc2305_fan",
109 "emc2305_fan1",
110 "emc2305_fan2",
111 "emc2305_fan3",
112 "emc2305_fan4",
113 "emc2305_fan5",
114};
115
116static void emc2305_unset_tz(struct device *dev);
117
118static int emc2305_get_max_channel(const struct emc2305_data *data)
119{
120 return data->pwm_num;
121}
122
123static int emc2305_get_cdev_idx(struct thermal_cooling_device *cdev)
124{
125 struct emc2305_data *data = cdev->devdata;
126 size_t len = strlen(cdev->type);
127 int ret;
128
129 if (len <= 0)
130 return -EINVAL;
131
132 /*
133 * Returns index of cooling device 0..4 in case of separate PWM setting.
134 * Zero index is used in case of one common PWM setting.
135 * If the mode is not set as pwm_separate, all PWMs are to be bound
136 * to the common thermal zone and should work at the same speed
137 * to perform cooling for the same thermal junction.
138 * Otherwise, return specific channel that will be used in bound
139 * related PWM to the thermal zone.
140 */
141 if (!data->pwm_separate)
142 return 0;
143
144 ret = cdev->type[len - 1];
145 switch (ret) {
146 case '1' ... '5':
147 return ret - '1';
148 default:
149 break;
150 }
151 return -EINVAL;
152}
153
154static int emc2305_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *state)
155{
156 int cdev_idx;
157 struct emc2305_data *data = cdev->devdata;
158
159 cdev_idx = emc2305_get_cdev_idx(cdev);
160 if (cdev_idx < 0)
161 return cdev_idx;
162
163 *state = data->cdev_data[cdev_idx].cur_state;
164 return 0;
165}
166
167static int emc2305_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state)
168{
169 struct emc2305_data *data = cdev->devdata;
170 *state = data->max_state;
171 return 0;
172}
173
174static int __emc2305_set_cur_state(struct emc2305_data *data, int cdev_idx, unsigned long state)
175{
176 int ret;
177 struct i2c_client *client = data->client;
178 u8 val, i;
179
180 state = max_t(unsigned long, state, data->cdev_data[cdev_idx].last_hwmon_state);
181
182 val = EMC2305_PWM_STATE2DUTY(state, data->max_state, EMC2305_FAN_MAX);
183
184 data->cdev_data[cdev_idx].cur_state = state;
185 if (data->pwm_separate) {
186 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(cdev_idx), val);
187 if (ret < 0)
188 return ret;
189 } else {
190 /*
191 * Set the same PWM value in all channels
192 * if common PWM channel is used.
193 */
194 for (i = 0; i < data->pwm_num; i++) {
195 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(i), val);
196 if (ret < 0)
197 return ret;
198 }
199 }
200
201 return 0;
202}
203
204static int emc2305_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
205{
206 int cdev_idx, ret;
207 struct emc2305_data *data = cdev->devdata;
208
209 if (state > data->max_state)
210 return -EINVAL;
211
212 cdev_idx = emc2305_get_cdev_idx(cdev);
213 if (cdev_idx < 0)
214 return cdev_idx;
215
216 /* Save thermal state. */
217 data->cdev_data[cdev_idx].last_thermal_state = state;
218 ret = __emc2305_set_cur_state(data, cdev_idx, state);
219 if (ret < 0)
220 return ret;
221
222 return 0;
223}
224
225static const struct thermal_cooling_device_ops emc2305_cooling_ops = {
226 .get_max_state = emc2305_get_max_state,
227 .get_cur_state = emc2305_get_cur_state,
228 .set_cur_state = emc2305_set_cur_state,
229};
230
231static int emc2305_show_fault(struct device *dev, int channel)
232{
233 struct emc2305_data *data = dev_get_drvdata(dev);
234 struct i2c_client *client = data->client;
235 int status_reg;
236
237 status_reg = i2c_smbus_read_byte_data(client, EMC2305_REG_DRIVE_FAIL_STATUS);
238 if (status_reg < 0)
239 return status_reg;
240
241 return status_reg & (1 << channel) ? 1 : 0;
242}
243
244static int emc2305_show_fan(struct device *dev, int channel)
245{
246 struct emc2305_data *data = dev_get_drvdata(dev);
247 struct i2c_client *client = data->client;
248 int ret;
249
250 ret = i2c_smbus_read_word_swapped(client, EMC2305_REG_FAN_TACH(channel));
251 if (ret <= 0)
252 return ret;
253
254 ret = ret >> EMC2305_TACH_REGS_UNUSE_BITS;
255 ret = EMC2305_RPM_FACTOR / ret;
256 if (ret <= EMC2305_TACH_RANGE_MIN)
257 return 0;
258
259 return ret * EMC2305_TACH_CNT_MULTIPLIER;
260}
261
262static int emc2305_show_pwm(struct device *dev, int channel)
263{
264 struct emc2305_data *data = dev_get_drvdata(dev);
265 struct i2c_client *client = data->client;
266
267 return i2c_smbus_read_byte_data(client, EMC2305_REG_FAN_DRIVE(channel));
268}
269
270static int emc2305_set_pwm(struct device *dev, long val, int channel)
271{
272 struct emc2305_data *data = dev_get_drvdata(dev);
273 struct i2c_client *client = data->client;
274 int ret;
275
276 if (val < data->pwm_min[channel] || val > EMC2305_FAN_MAX)
277 return -EINVAL;
278
279 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_DRIVE(channel), val);
280 if (ret < 0)
281 return ret;
282 data->cdev_data[channel].cur_state = EMC2305_PWM_DUTY2STATE(val, data->max_state,
283 EMC2305_FAN_MAX);
284 return 0;
285}
286
287static int emc2305_set_single_tz(struct device *dev, int idx)
288{
289 struct emc2305_data *data = dev_get_drvdata(dev);
290 long pwm;
291 int i, cdev_idx, ret;
292
293 cdev_idx = (idx) ? idx - 1 : 0;
294 pwm = data->pwm_min[cdev_idx];
295
296 data->cdev_data[cdev_idx].cdev =
297 thermal_cooling_device_register(emc2305_fan_name[idx], data,
298 &emc2305_cooling_ops);
299
300 if (IS_ERR(data->cdev_data[cdev_idx].cdev)) {
301 dev_err(dev, "Failed to register cooling device %s\n", emc2305_fan_name[idx]);
302 return PTR_ERR(data->cdev_data[cdev_idx].cdev);
303 }
304 /* Set minimal PWM speed. */
305 if (data->pwm_separate) {
306 ret = emc2305_set_pwm(dev, pwm, cdev_idx);
307 if (ret < 0)
308 return ret;
309 } else {
310 for (i = 0; i < data->pwm_num; i++) {
311 ret = emc2305_set_pwm(dev, pwm, i);
312 if (ret < 0)
313 return ret;
314 }
315 }
316 data->cdev_data[cdev_idx].cur_state =
317 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state,
318 EMC2305_FAN_MAX);
319 data->cdev_data[cdev_idx].last_hwmon_state =
320 EMC2305_PWM_DUTY2STATE(data->pwm_min[cdev_idx], data->max_state,
321 EMC2305_FAN_MAX);
322 return 0;
323}
324
325static int emc2305_set_tz(struct device *dev)
326{
327 struct emc2305_data *data = dev_get_drvdata(dev);
328 int i, ret;
329
330 if (!data->pwm_separate)
331 return emc2305_set_single_tz(dev, 0);
332
333 for (i = 0; i < data->pwm_num; i++) {
334 ret = emc2305_set_single_tz(dev, i + 1);
335 if (ret)
336 goto thermal_cooling_device_register_fail;
337 }
338 return 0;
339
340thermal_cooling_device_register_fail:
341 emc2305_unset_tz(dev);
342 return ret;
343}
344
345static void emc2305_unset_tz(struct device *dev)
346{
347 struct emc2305_data *data = dev_get_drvdata(dev);
348 int i;
349
350 /* Unregister cooling device. */
351 for (i = 0; i < EMC2305_PWM_MAX; i++)
352 if (data->cdev_data[i].cdev)
353 thermal_cooling_device_unregister(data->cdev_data[i].cdev);
354}
355
356static umode_t
357emc2305_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr, int channel)
358{
359 int max_channel = emc2305_get_max_channel(data);
360
361 /* Don't show channels which are not physically connected. */
362 if (channel >= max_channel)
363 return 0;
364 switch (type) {
365 case hwmon_fan:
366 switch (attr) {
367 case hwmon_fan_input:
368 return 0444;
369 case hwmon_fan_fault:
370 return 0444;
371 default:
372 break;
373 }
374 break;
375 case hwmon_pwm:
376 switch (attr) {
377 case hwmon_pwm_input:
378 return 0644;
379 default:
380 break;
381 }
382 break;
383 default:
384 break;
385 }
386
387 return 0;
388};
389
390static int
391emc2305_write(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long val)
392{
393 struct emc2305_data *data = dev_get_drvdata(dev);
394 int cdev_idx;
395
396 switch (type) {
397 case hwmon_pwm:
398 switch (attr) {
399 case hwmon_pwm_input:
400 /* If thermal is configured - handle PWM limit setting. */
401 if (IS_REACHABLE(CONFIG_THERMAL)) {
402 if (data->pwm_separate)
403 cdev_idx = channel;
404 else
405 cdev_idx = 0;
406 data->cdev_data[cdev_idx].last_hwmon_state =
407 EMC2305_PWM_DUTY2STATE(val, data->max_state,
408 EMC2305_FAN_MAX);
409 /*
410 * Update PWM only in case requested state is not less than the
411 * last thermal state.
412 */
413 if (data->cdev_data[cdev_idx].last_hwmon_state >=
414 data->cdev_data[cdev_idx].last_thermal_state)
415 return __emc2305_set_cur_state(data, cdev_idx,
416 data->cdev_data[cdev_idx].last_hwmon_state);
417 return 0;
418 }
419 return emc2305_set_pwm(dev, val, channel);
420 default:
421 break;
422 }
423 break;
424 default:
425 break;
426 }
427
428 return -EOPNOTSUPP;
429};
430
431static int
432emc2305_read(struct device *dev, enum hwmon_sensor_types type, u32 attr, int channel, long *val)
433{
434 int ret;
435
436 switch (type) {
437 case hwmon_fan:
438 switch (attr) {
439 case hwmon_fan_input:
440 ret = emc2305_show_fan(dev, channel);
441 if (ret < 0)
442 return ret;
443 *val = ret;
444 return 0;
445 case hwmon_fan_fault:
446 ret = emc2305_show_fault(dev, channel);
447 if (ret < 0)
448 return ret;
449 *val = ret;
450 return 0;
451 default:
452 break;
453 }
454 break;
455 case hwmon_pwm:
456 switch (attr) {
457 case hwmon_pwm_input:
458 ret = emc2305_show_pwm(dev, channel);
459 if (ret < 0)
460 return ret;
461 *val = ret;
462 return 0;
463 default:
464 break;
465 }
466 break;
467 default:
468 break;
469 }
470
471 return -EOPNOTSUPP;
472};
473
474static const struct hwmon_ops emc2305_ops = {
475 .is_visible = emc2305_is_visible,
476 .read = emc2305_read,
477 .write = emc2305_write,
478};
479
480static const struct hwmon_channel_info *emc2305_info[] = {
481 HWMON_CHANNEL_INFO(fan,
482 HWMON_F_INPUT | HWMON_F_FAULT,
483 HWMON_F_INPUT | HWMON_F_FAULT,
484 HWMON_F_INPUT | HWMON_F_FAULT,
485 HWMON_F_INPUT | HWMON_F_FAULT,
486 HWMON_F_INPUT | HWMON_F_FAULT),
487 HWMON_CHANNEL_INFO(pwm,
488 HWMON_PWM_INPUT,
489 HWMON_PWM_INPUT,
490 HWMON_PWM_INPUT,
491 HWMON_PWM_INPUT,
492 HWMON_PWM_INPUT),
493 NULL
494};
495
496static const struct hwmon_chip_info emc2305_chip_info = {
497 .ops = &emc2305_ops,
498 .info = emc2305_info,
499};
500
501static int emc2305_identify(struct device *dev)
502{
503 struct i2c_client *client = to_i2c_client(dev);
504 struct emc2305_data *data = i2c_get_clientdata(client);
505 int ret;
506
507 ret = i2c_smbus_read_byte_data(client, EMC2305_REG_PRODUCT_ID);
508 if (ret < 0)
509 return ret;
510
511 switch (ret) {
512 case EMC2305:
513 data->pwm_num = 5;
514 break;
515 case EMC2303:
516 data->pwm_num = 3;
517 break;
518 case EMC2302:
519 data->pwm_num = 2;
520 break;
521 case EMC2301:
522 data->pwm_num = 1;
523 break;
524 default:
525 return -ENODEV;
526 }
527
528 return 0;
529}
530
531static int emc2305_probe(struct i2c_client *client)
532{
533 struct i2c_adapter *adapter = client->adapter;
534 struct device *dev = &client->dev;
535 struct emc2305_data *data;
536 struct emc2305_platform_data *pdata;
537 int vendor;
538 int ret;
539 int i;
540
541 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
542 return -ENODEV;
543
544 vendor = i2c_smbus_read_byte_data(client, EMC2305_REG_VENDOR);
545 if (vendor != EMC2305_VENDOR)
546 return -ENODEV;
547
548 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
549 if (!data)
550 return -ENOMEM;
551
552 i2c_set_clientdata(client, data);
553 data->client = client;
554
555 ret = emc2305_identify(dev);
556 if (ret)
557 return ret;
558
559 pdata = dev_get_platdata(&client->dev);
560 if (pdata) {
561 if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE)
562 return -EINVAL;
563 data->max_state = pdata->max_state;
564 /*
565 * Validate a number of active PWM channels. Note that
566 * configured number can be less than the actual maximum
567 * supported by the device.
568 */
569 if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX)
570 return -EINVAL;
571 data->pwm_num = pdata->pwm_num;
572 data->pwm_separate = pdata->pwm_separate;
573 for (i = 0; i < EMC2305_PWM_MAX; i++)
574 data->pwm_min[i] = pdata->pwm_min[i];
575 } else {
576 data->max_state = EMC2305_FAN_MAX_STATE;
577 data->pwm_separate = false;
578 for (i = 0; i < EMC2305_PWM_MAX; i++)
579 data->pwm_min[i] = EMC2305_FAN_MIN;
580 }
581
582 data->hwmon_dev = devm_hwmon_device_register_with_info(dev, "emc2305", data,
583 &emc2305_chip_info, NULL);
584 if (IS_ERR(data->hwmon_dev))
585 return PTR_ERR(data->hwmon_dev);
586
587 if (IS_REACHABLE(CONFIG_THERMAL)) {
588 ret = emc2305_set_tz(dev);
589 if (ret != 0)
590 return ret;
591 }
592
593 for (i = 0; i < data->pwm_num; i++) {
594 ret = i2c_smbus_write_byte_data(client, EMC2305_REG_FAN_MIN_DRIVE(i),
595 data->pwm_min[i]);
596 if (ret < 0)
597 return ret;
598 }
599
600 return 0;
601}
602
603static void emc2305_remove(struct i2c_client *client)
604{
605 struct device *dev = &client->dev;
606
607 if (IS_REACHABLE(CONFIG_THERMAL))
608 emc2305_unset_tz(dev);
609}
610
611static struct i2c_driver emc2305_driver = {
612 .class = I2C_CLASS_HWMON,
613 .driver = {
614 .name = "emc2305",
615 },
616 .probe_new = emc2305_probe,
617 .remove = emc2305_remove,
618 .id_table = emc2305_ids,
619 .address_list = emc2305_normal_i2c,
620};
621
622module_i2c_driver(emc2305_driver);
623
624MODULE_AUTHOR("Nvidia");
625MODULE_DESCRIPTION("Microchip EMC2305 fan controller driver");
626MODULE_LICENSE("GPL");