1// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2//
3// Copyright (c) 2018 Mellanox Technologies. All rights reserved.
4// Copyright (c) 2018 Vadim Pasternak <vadimp@mellanox.com>
5
6#include <linux/bitops.h>
7#include <linux/device.h>
8#include <linux/hwmon.h>
9#include <linux/module.h>
10#include <linux/platform_data/mlxreg.h>
11#include <linux/platform_device.h>
12#include <linux/regmap.h>
13#include <linux/thermal.h>
14
15#define MLXREG_FAN_MAX_TACHO 24
16#define MLXREG_FAN_MAX_PWM 4
17#define MLXREG_FAN_PWM_NOT_CONNECTED 0xff
18#define MLXREG_FAN_MAX_STATE 10
19#define MLXREG_FAN_MIN_DUTY 51 /* 20% */
20#define MLXREG_FAN_MAX_DUTY 255 /* 100% */
21#define MLXREG_FAN_SPEED_MIN_LEVEL 2 /* 20 percent */
22#define MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF 44
23#define MLXREG_FAN_TACHO_DIV_MIN 283
24#define MLXREG_FAN_TACHO_DIV_DEF (MLXREG_FAN_TACHO_DIV_MIN * 4)
25#define MLXREG_FAN_TACHO_DIV_SCALE_MAX 64
26/*
27 * FAN datasheet defines the formula for RPM calculations as RPM = 15/t-high.
28 * The logic in a programmable device measures the time t-high by sampling the
29 * tachometer every t-sample (with the default value 11.32 uS) and increment
30 * a counter (N) as long as the pulse has not change:
31 * RPM = 15 / (t-sample * (K + Regval)), where:
32 * Regval: is the value read from the programmable device register;
33 * - 0xff - represents tachometer fault;
34 * - 0xfe - represents tachometer minimum value , which is 4444 RPM;
35 * - 0x00 - represents tachometer maximum value , which is 300000 RPM;
36 * K: is 44 and it represents the minimum allowed samples per pulse;
37 * N: is equal K + Regval;
38 * In order to calculate RPM from the register value the following formula is
39 * used: RPM = 15 / ((Regval + K) * 11.32) * 10^(-6)), which in the
40 * default case is modified to:
41 * RPM = 15000000 * 100 / ((Regval + 44) * 1132);
42 * - for Regval 0x00, RPM will be 15000000 * 100 / (44 * 1132) = 30115;
43 * - for Regval 0xfe, RPM will be 15000000 * 100 / ((254 + 44) * 1132) = 4446;
44 * In common case the formula is modified to:
45 * RPM = 15000000 * 100 / ((Regval + samples) * divider).
46 */
47#define MLXREG_FAN_GET_RPM(rval, d, s) (DIV_ROUND_CLOSEST(15000000 * 100, \
48 ((rval) + (s)) * (d)))
49#define MLXREG_FAN_GET_FAULT(val, mask) ((val) == (mask))
50#define MLXREG_FAN_PWM_DUTY2STATE(duty) (DIV_ROUND_CLOSEST((duty) * \
51 MLXREG_FAN_MAX_STATE, \
52 MLXREG_FAN_MAX_DUTY))
53#define MLXREG_FAN_PWM_STATE2DUTY(stat) (DIV_ROUND_CLOSEST((stat) * \
54 MLXREG_FAN_MAX_DUTY, \
55 MLXREG_FAN_MAX_STATE))
56
57struct mlxreg_fan;
58
59/*
60 * struct mlxreg_fan_tacho - tachometer data (internal use):
61 *
62 * @connected: indicates if tachometer is connected;
63 * @reg: register offset;
64 * @mask: fault mask;
65 * @prsnt: present register offset;
66 */
67struct mlxreg_fan_tacho {
68 bool connected;
69 u32 reg;
70 u32 mask;
71 u32 prsnt;
72};
73
74/*
75 * struct mlxreg_fan_pwm - PWM data (internal use):
76 *
77 * @fan: private data;
78 * @connected: indicates if PWM is connected;
79 * @reg: register offset;
80 * @cooling: cooling device levels;
81 * @last_hwmon_state: last cooling state set by hwmon subsystem;
82 * @last_thermal_state: last cooling state set by thermal subsystem;
83 * @cdev: cooling device;
84 */
85struct mlxreg_fan_pwm {
86 struct mlxreg_fan *fan;
87 bool connected;
88 u32 reg;
89 unsigned long last_hwmon_state;
90 unsigned long last_thermal_state;
91 struct thermal_cooling_device *cdev;
92};
93
94/*
95 * struct mlxreg_fan - private data (internal use):
96 *
97 * @dev: basic device;
98 * @regmap: register map of parent device;
99 * @tacho: tachometer data;
100 * @pwm: PWM data;
101 * @tachos_per_drwr - number of tachometers per drawer;
102 * @samples: minimum allowed samples per pulse;
103 * @divider: divider value for tachometer RPM calculation;
104 */
105struct mlxreg_fan {
106 struct device *dev;
107 void *regmap;
108 struct mlxreg_core_platform_data *pdata;
109 struct mlxreg_fan_tacho tacho[MLXREG_FAN_MAX_TACHO];
110 struct mlxreg_fan_pwm pwm[MLXREG_FAN_MAX_PWM];
111 int tachos_per_drwr;
112 int samples;
113 int divider;
114};
115
116static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,
117 unsigned long state);
118
119static int
120mlxreg_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
121 int channel, long *val)
122{
123 struct mlxreg_fan *fan = dev_get_drvdata(dev);
124 struct mlxreg_fan_tacho *tacho;
125 struct mlxreg_fan_pwm *pwm;
126 u32 regval;
127 int err;
128
129 switch (type) {
130 case hwmon_fan:
131 tacho = &fan->tacho[channel];
132 switch (attr) {
133 case hwmon_fan_input:
134 /*
135 * Check FAN presence: FAN related bit in presence register is one,
136 * if FAN is physically connected, zero - otherwise.
137 */
138 if (tacho->prsnt && fan->tachos_per_drwr) {
139 err = regmap_read(map: fan->regmap, reg: tacho->prsnt, val: &regval);
140 if (err)
141 return err;
142
143 /*
144 * Map channel to presence bit - drawer can be equipped with
145 * one or few FANs, while presence is indicated per drawer.
146 */
147 if (BIT(channel / fan->tachos_per_drwr) & regval) {
148 /* FAN is not connected - return zero for FAN speed. */
149 *val = 0;
150 return 0;
151 }
152 }
153
154 err = regmap_read(map: fan->regmap, reg: tacho->reg, val: &regval);
155 if (err)
156 return err;
157
158 if (MLXREG_FAN_GET_FAULT(regval, tacho->mask)) {
159 /* FAN is broken - return zero for FAN speed. */
160 *val = 0;
161 return 0;
162 }
163
164 *val = MLXREG_FAN_GET_RPM(regval, fan->divider,
165 fan->samples);
166 break;
167
168 case hwmon_fan_fault:
169 err = regmap_read(map: fan->regmap, reg: tacho->reg, val: &regval);
170 if (err)
171 return err;
172
173 *val = MLXREG_FAN_GET_FAULT(regval, tacho->mask);
174 break;
175
176 default:
177 return -EOPNOTSUPP;
178 }
179 break;
180
181 case hwmon_pwm:
182 pwm = &fan->pwm[channel];
183 switch (attr) {
184 case hwmon_pwm_input:
185 err = regmap_read(map: fan->regmap, reg: pwm->reg, val: &regval);
186 if (err)
187 return err;
188
189 *val = regval;
190 break;
191
192 default:
193 return -EOPNOTSUPP;
194 }
195 break;
196
197 default:
198 return -EOPNOTSUPP;
199 }
200
201 return 0;
202}
203
204static int
205mlxreg_fan_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
206 int channel, long val)
207{
208 struct mlxreg_fan *fan = dev_get_drvdata(dev);
209 struct mlxreg_fan_pwm *pwm;
210
211 switch (type) {
212 case hwmon_pwm:
213 switch (attr) {
214 case hwmon_pwm_input:
215 if (val < MLXREG_FAN_MIN_DUTY ||
216 val > MLXREG_FAN_MAX_DUTY)
217 return -EINVAL;
218 pwm = &fan->pwm[channel];
219 /* If thermal is configured - handle PWM limit setting. */
220 if (IS_REACHABLE(CONFIG_THERMAL)) {
221 pwm->last_hwmon_state = MLXREG_FAN_PWM_DUTY2STATE(val);
222 /*
223 * Update PWM only in case requested state is not less than the
224 * last thermal state.
225 */
226 if (pwm->last_hwmon_state >= pwm->last_thermal_state)
227 return mlxreg_fan_set_cur_state(cdev: pwm->cdev,
228 state: pwm->last_hwmon_state);
229 return 0;
230 }
231 return regmap_write(map: fan->regmap, reg: pwm->reg, val);
232 default:
233 return -EOPNOTSUPP;
234 }
235 break;
236
237 default:
238 return -EOPNOTSUPP;
239 }
240
241 return -EOPNOTSUPP;
242}
243
244static umode_t
245mlxreg_fan_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
246 int channel)
247{
248 switch (type) {
249 case hwmon_fan:
250 if (!(((struct mlxreg_fan *)data)->tacho[channel].connected))
251 return 0;
252
253 switch (attr) {
254 case hwmon_fan_input:
255 case hwmon_fan_fault:
256 return 0444;
257 default:
258 break;
259 }
260 break;
261
262 case hwmon_pwm:
263 if (!(((struct mlxreg_fan *)data)->pwm[channel].connected))
264 return 0;
265
266 switch (attr) {
267 case hwmon_pwm_input:
268 return 0644;
269 default:
270 break;
271 }
272 break;
273
274 default:
275 break;
276 }
277
278 return 0;
279}
280
281static char *mlxreg_fan_name[] = {
282 "mlxreg_fan",
283 "mlxreg_fan1",
284 "mlxreg_fan2",
285 "mlxreg_fan3",
286};
287
288static const struct hwmon_channel_info * const mlxreg_fan_hwmon_info[] = {
289 HWMON_CHANNEL_INFO(fan,
290 HWMON_F_INPUT | HWMON_F_FAULT,
291 HWMON_F_INPUT | HWMON_F_FAULT,
292 HWMON_F_INPUT | HWMON_F_FAULT,
293 HWMON_F_INPUT | HWMON_F_FAULT,
294 HWMON_F_INPUT | HWMON_F_FAULT,
295 HWMON_F_INPUT | HWMON_F_FAULT,
296 HWMON_F_INPUT | HWMON_F_FAULT,
297 HWMON_F_INPUT | HWMON_F_FAULT,
298 HWMON_F_INPUT | HWMON_F_FAULT,
299 HWMON_F_INPUT | HWMON_F_FAULT,
300 HWMON_F_INPUT | HWMON_F_FAULT,
301 HWMON_F_INPUT | HWMON_F_FAULT,
302 HWMON_F_INPUT | HWMON_F_FAULT,
303 HWMON_F_INPUT | HWMON_F_FAULT,
304 HWMON_F_INPUT | HWMON_F_FAULT,
305 HWMON_F_INPUT | HWMON_F_FAULT,
306 HWMON_F_INPUT | HWMON_F_FAULT,
307 HWMON_F_INPUT | HWMON_F_FAULT,
308 HWMON_F_INPUT | HWMON_F_FAULT,
309 HWMON_F_INPUT | HWMON_F_FAULT,
310 HWMON_F_INPUT | HWMON_F_FAULT,
311 HWMON_F_INPUT | HWMON_F_FAULT,
312 HWMON_F_INPUT | HWMON_F_FAULT,
313 HWMON_F_INPUT | HWMON_F_FAULT),
314 HWMON_CHANNEL_INFO(pwm,
315 HWMON_PWM_INPUT,
316 HWMON_PWM_INPUT,
317 HWMON_PWM_INPUT,
318 HWMON_PWM_INPUT),
319 NULL
320};
321
322static const struct hwmon_ops mlxreg_fan_hwmon_hwmon_ops = {
323 .is_visible = mlxreg_fan_is_visible,
324 .read = mlxreg_fan_read,
325 .write = mlxreg_fan_write,
326};
327
328static const struct hwmon_chip_info mlxreg_fan_hwmon_chip_info = {
329 .ops = &mlxreg_fan_hwmon_hwmon_ops,
330 .info = mlxreg_fan_hwmon_info,
331};
332
333static int mlxreg_fan_get_max_state(struct thermal_cooling_device *cdev,
334 unsigned long *state)
335{
336 *state = MLXREG_FAN_MAX_STATE;
337 return 0;
338}
339
340static int mlxreg_fan_get_cur_state(struct thermal_cooling_device *cdev,
341 unsigned long *state)
342
343{
344 struct mlxreg_fan_pwm *pwm = cdev->devdata;
345 struct mlxreg_fan *fan = pwm->fan;
346 u32 regval;
347 int err;
348
349 err = regmap_read(map: fan->regmap, reg: pwm->reg, val: &regval);
350 if (err) {
351 dev_err(fan->dev, "Failed to query PWM duty\n");
352 return err;
353 }
354
355 *state = MLXREG_FAN_PWM_DUTY2STATE(regval);
356
357 return 0;
358}
359
360static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,
361 unsigned long state)
362
363{
364 struct mlxreg_fan_pwm *pwm = cdev->devdata;
365 struct mlxreg_fan *fan = pwm->fan;
366 int err;
367
368 if (state > MLXREG_FAN_MAX_STATE)
369 return -EINVAL;
370
371 /* Save thermal state. */
372 pwm->last_thermal_state = state;
373
374 state = max_t(unsigned long, state, pwm->last_hwmon_state);
375 err = regmap_write(map: fan->regmap, reg: pwm->reg,
376 MLXREG_FAN_PWM_STATE2DUTY(state));
377 if (err) {
378 dev_err(fan->dev, "Failed to write PWM duty\n");
379 return err;
380 }
381 return 0;
382}
383
384static const struct thermal_cooling_device_ops mlxreg_fan_cooling_ops = {
385 .get_max_state = mlxreg_fan_get_max_state,
386 .get_cur_state = mlxreg_fan_get_cur_state,
387 .set_cur_state = mlxreg_fan_set_cur_state,
388};
389
390static int mlxreg_fan_connect_verify(struct mlxreg_fan *fan,
391 struct mlxreg_core_data *data)
392{
393 u32 regval;
394 int err;
395
396 err = regmap_read(map: fan->regmap, reg: data->capability, val: &regval);
397 if (err) {
398 dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
399 data->capability);
400 return err;
401 }
402
403 return !!(regval & data->bit);
404}
405
406static int mlxreg_pwm_connect_verify(struct mlxreg_fan *fan,
407 struct mlxreg_core_data *data)
408{
409 u32 regval;
410 int err;
411
412 err = regmap_read(map: fan->regmap, reg: data->reg, val: &regval);
413 if (err) {
414 dev_err(fan->dev, "Failed to query pwm register 0x%08x\n",
415 data->reg);
416 return err;
417 }
418
419 return regval != MLXREG_FAN_PWM_NOT_CONNECTED;
420}
421
422static int mlxreg_fan_speed_divider_get(struct mlxreg_fan *fan,
423 struct mlxreg_core_data *data)
424{
425 u32 regval;
426 int err;
427
428 err = regmap_read(map: fan->regmap, reg: data->capability, val: &regval);
429 if (err) {
430 dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
431 data->capability);
432 return err;
433 }
434
435 /*
436 * Set divider value according to the capability register, in case it
437 * contains valid value. Otherwise use default value. The purpose of
438 * this validation is to protect against the old hardware, in which
439 * this register can return zero.
440 */
441 if (regval > 0 && regval <= MLXREG_FAN_TACHO_DIV_SCALE_MAX)
442 fan->divider = regval * MLXREG_FAN_TACHO_DIV_MIN;
443
444 return 0;
445}
446
447static int mlxreg_fan_config(struct mlxreg_fan *fan,
448 struct mlxreg_core_platform_data *pdata)
449{
450 int tacho_num = 0, tacho_avail = 0, pwm_num = 0, i;
451 struct mlxreg_core_data *data = pdata->data;
452 bool configured = false;
453 int err;
454
455 fan->samples = MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF;
456 fan->divider = MLXREG_FAN_TACHO_DIV_DEF;
457 for (i = 0; i < pdata->counter; i++, data++) {
458 if (strnstr(data->label, "tacho", sizeof(data->label))) {
459 if (tacho_num == MLXREG_FAN_MAX_TACHO) {
460 dev_err(fan->dev, "too many tacho entries: %s\n",
461 data->label);
462 return -EINVAL;
463 }
464
465 if (data->capability) {
466 err = mlxreg_fan_connect_verify(fan, data);
467 if (err < 0)
468 return err;
469 else if (!err) {
470 tacho_num++;
471 continue;
472 }
473 }
474
475 fan->tacho[tacho_num].reg = data->reg;
476 fan->tacho[tacho_num].mask = data->mask;
477 fan->tacho[tacho_num].prsnt = data->reg_prsnt;
478 fan->tacho[tacho_num++].connected = true;
479 tacho_avail++;
480 } else if (strnstr(data->label, "pwm", sizeof(data->label))) {
481 if (pwm_num == MLXREG_FAN_MAX_TACHO) {
482 dev_err(fan->dev, "too many pwm entries: %s\n",
483 data->label);
484 return -EINVAL;
485 }
486
487 /* Validate if more then one PWM is connected. */
488 if (pwm_num) {
489 err = mlxreg_pwm_connect_verify(fan, data);
490 if (err < 0)
491 return err;
492 else if (!err)
493 continue;
494 }
495
496 fan->pwm[pwm_num].reg = data->reg;
497 fan->pwm[pwm_num].connected = true;
498 pwm_num++;
499 } else if (strnstr(data->label, "conf", sizeof(data->label))) {
500 if (configured) {
501 dev_err(fan->dev, "duplicate conf entry: %s\n",
502 data->label);
503 return -EINVAL;
504 }
505 /* Validate that conf parameters are not zeros. */
506 if (!data->mask && !data->bit && !data->capability) {
507 dev_err(fan->dev, "invalid conf entry params: %s\n",
508 data->label);
509 return -EINVAL;
510 }
511 if (data->capability) {
512 err = mlxreg_fan_speed_divider_get(fan, data);
513 if (err)
514 return err;
515 } else {
516 if (data->mask)
517 fan->samples = data->mask;
518 if (data->bit)
519 fan->divider = data->bit;
520 }
521 configured = true;
522 } else {
523 dev_err(fan->dev, "invalid label: %s\n", data->label);
524 return -EINVAL;
525 }
526 }
527
528 if (pdata->capability) {
529 int drwr_avail;
530 u32 regval;
531
532 /* Obtain the number of FAN drawers, supported by system. */
533 err = regmap_read(map: fan->regmap, reg: pdata->capability, val: &regval);
534 if (err) {
535 dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
536 pdata->capability);
537 return err;
538 }
539
540 drwr_avail = hweight32(regval);
541 if (!tacho_avail || !drwr_avail || tacho_avail < drwr_avail) {
542 dev_err(fan->dev, "Configuration is invalid: drawers num %d tachos num %d\n",
543 drwr_avail, tacho_avail);
544 return -EINVAL;
545 }
546
547 /* Set the number of tachometers per one drawer. */
548 fan->tachos_per_drwr = tacho_avail / drwr_avail;
549 }
550
551 return 0;
552}
553
554static int mlxreg_fan_cooling_config(struct device *dev, struct mlxreg_fan *fan)
555{
556 int i;
557
558 for (i = 0; i < MLXREG_FAN_MAX_PWM; i++) {
559 struct mlxreg_fan_pwm *pwm = &fan->pwm[i];
560
561 if (!pwm->connected)
562 continue;
563 pwm->fan = fan;
564 pwm->cdev = devm_thermal_of_cooling_device_register(dev, NULL, type: mlxreg_fan_name[i],
565 devdata: pwm, ops: &mlxreg_fan_cooling_ops);
566 if (IS_ERR(ptr: pwm->cdev)) {
567 dev_err(dev, "Failed to register cooling device\n");
568 return PTR_ERR(ptr: pwm->cdev);
569 }
570
571 /* Set minimal PWM speed. */
572 pwm->last_hwmon_state = MLXREG_FAN_PWM_DUTY2STATE(MLXREG_FAN_MIN_DUTY);
573 }
574
575 return 0;
576}
577
578static int mlxreg_fan_probe(struct platform_device *pdev)
579{
580 struct mlxreg_core_platform_data *pdata;
581 struct device *dev = &pdev->dev;
582 struct mlxreg_fan *fan;
583 struct device *hwm;
584 int err;
585
586 pdata = dev_get_platdata(dev);
587 if (!pdata) {
588 dev_err(dev, "Failed to get platform data.\n");
589 return -EINVAL;
590 }
591
592 fan = devm_kzalloc(dev, size: sizeof(*fan), GFP_KERNEL);
593 if (!fan)
594 return -ENOMEM;
595
596 fan->dev = dev;
597 fan->regmap = pdata->regmap;
598
599 err = mlxreg_fan_config(fan, pdata);
600 if (err)
601 return err;
602
603 hwm = devm_hwmon_device_register_with_info(dev, name: "mlxreg_fan",
604 drvdata: fan,
605 info: &mlxreg_fan_hwmon_chip_info,
606 NULL);
607 if (IS_ERR(ptr: hwm)) {
608 dev_err(dev, "Failed to register hwmon device\n");
609 return PTR_ERR(ptr: hwm);
610 }
611
612 if (IS_REACHABLE(CONFIG_THERMAL))
613 err = mlxreg_fan_cooling_config(dev, fan);
614
615 return err;
616}
617
618static struct platform_driver mlxreg_fan_driver = {
619 .driver = {
620 .name = "mlxreg-fan",
621 },
622 .probe = mlxreg_fan_probe,
623};
624
625module_platform_driver(mlxreg_fan_driver);
626
627MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
628MODULE_DESCRIPTION("Mellanox FAN driver");
629MODULE_LICENSE("GPL");
630MODULE_ALIAS("platform:mlxreg-fan");
631

source code of linux/drivers/hwmon/mlxreg-fan.c