xref: /openbmc/linux/drivers/hwmon/mlxreg-fan.c (revision b9221f71)
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		12
16 #define MLXREG_FAN_MAX_STATE		10
17 #define MLXREG_FAN_MIN_DUTY		51	/* 20% */
18 #define MLXREG_FAN_MAX_DUTY		255	/* 100% */
19 /*
20  * Minimum and maximum FAN allowed speed in percent: from 20% to 100%. Values
21  * MLXREG_FAN_MAX_STATE + x, where x is between 2 and 10 are used for
22  * setting FAN speed dynamic minimum. For example, if value is set to 14 (40%)
23  * cooling levels vector will be set to 4, 4, 4, 4, 4, 5, 6, 7, 8, 9, 10 to
24  * introduce PWM speed in percent: 40, 40, 40, 40, 40, 50, 60. 70, 80, 90, 100.
25  */
26 #define MLXREG_FAN_SPEED_MIN			(MLXREG_FAN_MAX_STATE + 2)
27 #define MLXREG_FAN_SPEED_MAX			(MLXREG_FAN_MAX_STATE * 2)
28 #define MLXREG_FAN_SPEED_MIN_LEVEL		2	/* 20 percent */
29 #define MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF	44
30 #define MLXREG_FAN_TACHO_DIV_MIN		283
31 #define MLXREG_FAN_TACHO_DIV_DEF		(MLXREG_FAN_TACHO_DIV_MIN * 4)
32 #define MLXREG_FAN_TACHO_DIV_SCALE_MAX	64
33 /*
34  * FAN datasheet defines the formula for RPM calculations as RPM = 15/t-high.
35  * The logic in a programmable device measures the time t-high by sampling the
36  * tachometer every t-sample (with the default value 11.32 uS) and increment
37  * a counter (N) as long as the pulse has not change:
38  * RPM = 15 / (t-sample * (K + Regval)), where:
39  * Regval: is the value read from the programmable device register;
40  *  - 0xff - represents tachometer fault;
41  *  - 0xfe - represents tachometer minimum value , which is 4444 RPM;
42  *  - 0x00 - represents tachometer maximum value , which is 300000 RPM;
43  * K: is 44 and it represents the minimum allowed samples per pulse;
44  * N: is equal K + Regval;
45  * In order to calculate RPM from the register value the following formula is
46  * used: RPM = 15 / ((Regval + K) * 11.32) * 10^(-6)), which in  the
47  * default case is modified to:
48  * RPM = 15000000 * 100 / ((Regval + 44) * 1132);
49  * - for Regval 0x00, RPM will be 15000000 * 100 / (44 * 1132) = 30115;
50  * - for Regval 0xfe, RPM will be 15000000 * 100 / ((254 + 44) * 1132) = 4446;
51  * In common case the formula is modified to:
52  * RPM = 15000000 * 100 / ((Regval + samples) * divider).
53  */
54 #define MLXREG_FAN_GET_RPM(rval, d, s)	(DIV_ROUND_CLOSEST(15000000 * 100, \
55 					 ((rval) + (s)) * (d)))
56 #define MLXREG_FAN_GET_FAULT(val, mask) ((val) == (mask))
57 #define MLXREG_FAN_PWM_DUTY2STATE(duty)	(DIV_ROUND_CLOSEST((duty) *	\
58 					 MLXREG_FAN_MAX_STATE,		\
59 					 MLXREG_FAN_MAX_DUTY))
60 #define MLXREG_FAN_PWM_STATE2DUTY(stat)	(DIV_ROUND_CLOSEST((stat) *	\
61 					 MLXREG_FAN_MAX_DUTY,		\
62 					 MLXREG_FAN_MAX_STATE))
63 
64 /*
65  * struct mlxreg_fan_tacho - tachometer data (internal use):
66  *
67  * @connected: indicates if tachometer is connected;
68  * @reg: register offset;
69  * @mask: fault mask;
70  * @prsnt: present register offset;
71  */
72 struct mlxreg_fan_tacho {
73 	bool connected;
74 	u32 reg;
75 	u32 mask;
76 	u32 prsnt;
77 };
78 
79 /*
80  * struct mlxreg_fan_pwm - PWM data (internal use):
81  *
82  * @connected: indicates if PWM is connected;
83  * @reg: register offset;
84  */
85 struct mlxreg_fan_pwm {
86 	bool connected;
87 	u32 reg;
88 };
89 
90 /*
91  * struct mlxreg_fan - private data (internal use):
92  *
93  * @dev: basic device;
94  * @regmap: register map of parent device;
95  * @tacho: tachometer data;
96  * @pwm: PWM data;
97  * @tachos_per_drwr - number of tachometers per drawer;
98  * @samples: minimum allowed samples per pulse;
99  * @divider: divider value for tachometer RPM calculation;
100  * @cooling: cooling device levels;
101  * @cdev: cooling device;
102  */
103 struct mlxreg_fan {
104 	struct device *dev;
105 	void *regmap;
106 	struct mlxreg_core_platform_data *pdata;
107 	struct mlxreg_fan_tacho tacho[MLXREG_FAN_MAX_TACHO];
108 	struct mlxreg_fan_pwm pwm;
109 	int tachos_per_drwr;
110 	int samples;
111 	int divider;
112 	u8 cooling_levels[MLXREG_FAN_MAX_STATE + 1];
113 	struct thermal_cooling_device *cdev;
114 };
115 
116 static int
117 mlxreg_fan_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
118 		int channel, long *val)
119 {
120 	struct mlxreg_fan *fan = dev_get_drvdata(dev);
121 	struct mlxreg_fan_tacho *tacho;
122 	u32 regval;
123 	int err;
124 
125 	switch (type) {
126 	case hwmon_fan:
127 		tacho = &fan->tacho[channel];
128 		switch (attr) {
129 		case hwmon_fan_input:
130 			/*
131 			 * Check FAN presence: FAN related bit in presence register is one,
132 			 * if FAN is physically connected, zero - otherwise.
133 			 */
134 			if (tacho->prsnt && fan->tachos_per_drwr) {
135 				err = regmap_read(fan->regmap, tacho->prsnt, &regval);
136 				if (err)
137 					return err;
138 
139 				/*
140 				 * Map channel to presence bit - drawer can be equipped with
141 				 * one or few FANs, while presence is indicated per drawer.
142 				 */
143 				if (BIT(channel / fan->tachos_per_drwr) & regval) {
144 					/* FAN is not connected - return zero for FAN speed. */
145 					*val = 0;
146 					return 0;
147 				}
148 			}
149 
150 			err = regmap_read(fan->regmap, tacho->reg, &regval);
151 			if (err)
152 				return err;
153 
154 			*val = MLXREG_FAN_GET_RPM(regval, fan->divider,
155 						  fan->samples);
156 			break;
157 
158 		case hwmon_fan_fault:
159 			err = regmap_read(fan->regmap, tacho->reg, &regval);
160 			if (err)
161 				return err;
162 
163 			*val = MLXREG_FAN_GET_FAULT(regval, tacho->mask);
164 			break;
165 
166 		default:
167 			return -EOPNOTSUPP;
168 		}
169 		break;
170 
171 	case hwmon_pwm:
172 		switch (attr) {
173 		case hwmon_pwm_input:
174 			err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
175 			if (err)
176 				return err;
177 
178 			*val = regval;
179 			break;
180 
181 		default:
182 			return -EOPNOTSUPP;
183 		}
184 		break;
185 
186 	default:
187 		return -EOPNOTSUPP;
188 	}
189 
190 	return 0;
191 }
192 
193 static int
194 mlxreg_fan_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
195 		 int channel, long val)
196 {
197 	struct mlxreg_fan *fan = dev_get_drvdata(dev);
198 
199 	switch (type) {
200 	case hwmon_pwm:
201 		switch (attr) {
202 		case hwmon_pwm_input:
203 			if (val < MLXREG_FAN_MIN_DUTY ||
204 			    val > MLXREG_FAN_MAX_DUTY)
205 				return -EINVAL;
206 			return regmap_write(fan->regmap, fan->pwm.reg, val);
207 		default:
208 			return -EOPNOTSUPP;
209 		}
210 		break;
211 
212 	default:
213 		return -EOPNOTSUPP;
214 	}
215 
216 	return -EOPNOTSUPP;
217 }
218 
219 static umode_t
220 mlxreg_fan_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
221 		      int channel)
222 {
223 	switch (type) {
224 	case hwmon_fan:
225 		if (!(((struct mlxreg_fan *)data)->tacho[channel].connected))
226 			return 0;
227 
228 		switch (attr) {
229 		case hwmon_fan_input:
230 		case hwmon_fan_fault:
231 			return 0444;
232 		default:
233 			break;
234 		}
235 		break;
236 
237 	case hwmon_pwm:
238 		if (!(((struct mlxreg_fan *)data)->pwm.connected))
239 			return 0;
240 
241 		switch (attr) {
242 		case hwmon_pwm_input:
243 			return 0644;
244 		default:
245 			break;
246 		}
247 		break;
248 
249 	default:
250 		break;
251 	}
252 
253 	return 0;
254 }
255 
256 static const struct hwmon_channel_info *mlxreg_fan_hwmon_info[] = {
257 	HWMON_CHANNEL_INFO(fan,
258 			   HWMON_F_INPUT | HWMON_F_FAULT,
259 			   HWMON_F_INPUT | HWMON_F_FAULT,
260 			   HWMON_F_INPUT | HWMON_F_FAULT,
261 			   HWMON_F_INPUT | HWMON_F_FAULT,
262 			   HWMON_F_INPUT | HWMON_F_FAULT,
263 			   HWMON_F_INPUT | HWMON_F_FAULT,
264 			   HWMON_F_INPUT | HWMON_F_FAULT,
265 			   HWMON_F_INPUT | HWMON_F_FAULT,
266 			   HWMON_F_INPUT | HWMON_F_FAULT,
267 			   HWMON_F_INPUT | HWMON_F_FAULT,
268 			   HWMON_F_INPUT | HWMON_F_FAULT,
269 			   HWMON_F_INPUT | HWMON_F_FAULT),
270 	HWMON_CHANNEL_INFO(pwm,
271 			   HWMON_PWM_INPUT),
272 	NULL
273 };
274 
275 static const struct hwmon_ops mlxreg_fan_hwmon_hwmon_ops = {
276 	.is_visible = mlxreg_fan_is_visible,
277 	.read = mlxreg_fan_read,
278 	.write = mlxreg_fan_write,
279 };
280 
281 static const struct hwmon_chip_info mlxreg_fan_hwmon_chip_info = {
282 	.ops = &mlxreg_fan_hwmon_hwmon_ops,
283 	.info = mlxreg_fan_hwmon_info,
284 };
285 
286 static int mlxreg_fan_get_max_state(struct thermal_cooling_device *cdev,
287 				    unsigned long *state)
288 {
289 	*state = MLXREG_FAN_MAX_STATE;
290 	return 0;
291 }
292 
293 static int mlxreg_fan_get_cur_state(struct thermal_cooling_device *cdev,
294 				    unsigned long *state)
295 
296 {
297 	struct mlxreg_fan *fan = cdev->devdata;
298 	u32 regval;
299 	int err;
300 
301 	err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
302 	if (err) {
303 		dev_err(fan->dev, "Failed to query PWM duty\n");
304 		return err;
305 	}
306 
307 	*state = MLXREG_FAN_PWM_DUTY2STATE(regval);
308 
309 	return 0;
310 }
311 
312 static int mlxreg_fan_set_cur_state(struct thermal_cooling_device *cdev,
313 				    unsigned long state)
314 
315 {
316 	struct mlxreg_fan *fan = cdev->devdata;
317 	unsigned long cur_state;
318 	int i, config = 0;
319 	u32 regval;
320 	int err;
321 
322 	/*
323 	 * Verify if this request is for changing allowed FAN dynamical
324 	 * minimum. If it is - update cooling levels accordingly and update
325 	 * state, if current state is below the newly requested minimum state.
326 	 * For example, if current state is 5, and minimal state is to be
327 	 * changed from 4 to 6, fan->cooling_levels[0 to 5] will be changed all
328 	 * from 4 to 6. And state 5 (fan->cooling_levels[4]) should be
329 	 * overwritten.
330 	 */
331 	if (state >= MLXREG_FAN_SPEED_MIN && state <= MLXREG_FAN_SPEED_MAX) {
332 		/*
333 		 * This is configuration change, which is only supported through sysfs.
334 		 * For configuration non-zero value is to be returned to avoid thermal
335 		 * statistics update.
336 		 */
337 		config = 1;
338 		state -= MLXREG_FAN_MAX_STATE;
339 		for (i = 0; i < state; i++)
340 			fan->cooling_levels[i] = state;
341 		for (i = state; i <= MLXREG_FAN_MAX_STATE; i++)
342 			fan->cooling_levels[i] = i;
343 
344 		err = regmap_read(fan->regmap, fan->pwm.reg, &regval);
345 		if (err) {
346 			dev_err(fan->dev, "Failed to query PWM duty\n");
347 			return err;
348 		}
349 
350 		cur_state = MLXREG_FAN_PWM_DUTY2STATE(regval);
351 		if (state < cur_state)
352 			return config;
353 
354 		state = cur_state;
355 	}
356 
357 	if (state > MLXREG_FAN_MAX_STATE)
358 		return -EINVAL;
359 
360 	/* Normalize the state to the valid speed range. */
361 	state = fan->cooling_levels[state];
362 	err = regmap_write(fan->regmap, fan->pwm.reg,
363 			   MLXREG_FAN_PWM_STATE2DUTY(state));
364 	if (err) {
365 		dev_err(fan->dev, "Failed to write PWM duty\n");
366 		return err;
367 	}
368 	return config;
369 }
370 
371 static const struct thermal_cooling_device_ops mlxreg_fan_cooling_ops = {
372 	.get_max_state	= mlxreg_fan_get_max_state,
373 	.get_cur_state	= mlxreg_fan_get_cur_state,
374 	.set_cur_state	= mlxreg_fan_set_cur_state,
375 };
376 
377 static int mlxreg_fan_connect_verify(struct mlxreg_fan *fan,
378 				     struct mlxreg_core_data *data)
379 {
380 	u32 regval;
381 	int err;
382 
383 	err = regmap_read(fan->regmap, data->capability, &regval);
384 	if (err) {
385 		dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
386 			data->capability);
387 		return err;
388 	}
389 
390 	return !!(regval & data->bit);
391 }
392 
393 static int mlxreg_fan_speed_divider_get(struct mlxreg_fan *fan,
394 					struct mlxreg_core_data *data)
395 {
396 	u32 regval;
397 	int err;
398 
399 	err = regmap_read(fan->regmap, data->capability, &regval);
400 	if (err) {
401 		dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
402 			data->capability);
403 		return err;
404 	}
405 
406 	/*
407 	 * Set divider value according to the capability register, in case it
408 	 * contains valid value. Otherwise use default value. The purpose of
409 	 * this validation is to protect against the old hardware, in which
410 	 * this register can return zero.
411 	 */
412 	if (regval > 0 && regval <= MLXREG_FAN_TACHO_DIV_SCALE_MAX)
413 		fan->divider = regval * MLXREG_FAN_TACHO_DIV_MIN;
414 
415 	return 0;
416 }
417 
418 static int mlxreg_fan_config(struct mlxreg_fan *fan,
419 			     struct mlxreg_core_platform_data *pdata)
420 {
421 	struct mlxreg_core_data *data = pdata->data;
422 	int tacho_num = 0, tacho_avail = 0, i;
423 	bool configured = false;
424 	int err;
425 
426 	fan->samples = MLXREG_FAN_TACHO_SAMPLES_PER_PULSE_DEF;
427 	fan->divider = MLXREG_FAN_TACHO_DIV_DEF;
428 	for (i = 0; i < pdata->counter; i++, data++) {
429 		if (strnstr(data->label, "tacho", sizeof(data->label))) {
430 			if (tacho_num == MLXREG_FAN_MAX_TACHO) {
431 				dev_err(fan->dev, "too many tacho entries: %s\n",
432 					data->label);
433 				return -EINVAL;
434 			}
435 
436 			if (data->capability) {
437 				err = mlxreg_fan_connect_verify(fan, data);
438 				if (err < 0)
439 					return err;
440 				else if (!err) {
441 					tacho_num++;
442 					continue;
443 				}
444 			}
445 
446 			fan->tacho[tacho_num].reg = data->reg;
447 			fan->tacho[tacho_num].mask = data->mask;
448 			fan->tacho[tacho_num].prsnt = data->reg_prsnt;
449 			fan->tacho[tacho_num++].connected = true;
450 			tacho_avail++;
451 		} else if (strnstr(data->label, "pwm", sizeof(data->label))) {
452 			if (fan->pwm.connected) {
453 				dev_err(fan->dev, "duplicate pwm entry: %s\n",
454 					data->label);
455 				return -EINVAL;
456 			}
457 			fan->pwm.reg = data->reg;
458 			fan->pwm.connected = true;
459 		} else if (strnstr(data->label, "conf", sizeof(data->label))) {
460 			if (configured) {
461 				dev_err(fan->dev, "duplicate conf entry: %s\n",
462 					data->label);
463 				return -EINVAL;
464 			}
465 			/* Validate that conf parameters are not zeros. */
466 			if (!data->mask && !data->bit && !data->capability) {
467 				dev_err(fan->dev, "invalid conf entry params: %s\n",
468 					data->label);
469 				return -EINVAL;
470 			}
471 			if (data->capability) {
472 				err = mlxreg_fan_speed_divider_get(fan, data);
473 				if (err)
474 					return err;
475 			} else {
476 				if (data->mask)
477 					fan->samples = data->mask;
478 				if (data->bit)
479 					fan->divider = data->bit;
480 			}
481 			configured = true;
482 		} else {
483 			dev_err(fan->dev, "invalid label: %s\n", data->label);
484 			return -EINVAL;
485 		}
486 	}
487 
488 	if (pdata->capability) {
489 		int drwr_avail;
490 		u32 regval;
491 
492 		/* Obtain the number of FAN drawers, supported by system. */
493 		err = regmap_read(fan->regmap, pdata->capability, &regval);
494 		if (err) {
495 			dev_err(fan->dev, "Failed to query capability register 0x%08x\n",
496 				pdata->capability);
497 			return err;
498 		}
499 
500 		drwr_avail = hweight32(regval);
501 		if (!tacho_avail || !drwr_avail || tacho_avail < drwr_avail) {
502 			dev_err(fan->dev, "Configuration is invalid: drawers num %d tachos num %d\n",
503 				drwr_avail, tacho_avail);
504 			return -EINVAL;
505 		}
506 
507 		/* Set the number of tachometers per one drawer. */
508 		fan->tachos_per_drwr = tacho_avail / drwr_avail;
509 	}
510 
511 	/* Init cooling levels per PWM state. */
512 	for (i = 0; i < MLXREG_FAN_SPEED_MIN_LEVEL; i++)
513 		fan->cooling_levels[i] = MLXREG_FAN_SPEED_MIN_LEVEL;
514 	for (i = MLXREG_FAN_SPEED_MIN_LEVEL; i <= MLXREG_FAN_MAX_STATE; i++)
515 		fan->cooling_levels[i] = i;
516 
517 	return 0;
518 }
519 
520 static int mlxreg_fan_probe(struct platform_device *pdev)
521 {
522 	struct mlxreg_core_platform_data *pdata;
523 	struct device *dev = &pdev->dev;
524 	struct mlxreg_fan *fan;
525 	struct device *hwm;
526 	int err;
527 
528 	pdata = dev_get_platdata(dev);
529 	if (!pdata) {
530 		dev_err(dev, "Failed to get platform data.\n");
531 		return -EINVAL;
532 	}
533 
534 	fan = devm_kzalloc(dev, sizeof(*fan), GFP_KERNEL);
535 	if (!fan)
536 		return -ENOMEM;
537 
538 	fan->dev = dev;
539 	fan->regmap = pdata->regmap;
540 
541 	err = mlxreg_fan_config(fan, pdata);
542 	if (err)
543 		return err;
544 
545 	hwm = devm_hwmon_device_register_with_info(dev, "mlxreg_fan",
546 						   fan,
547 						   &mlxreg_fan_hwmon_chip_info,
548 						   NULL);
549 	if (IS_ERR(hwm)) {
550 		dev_err(dev, "Failed to register hwmon device\n");
551 		return PTR_ERR(hwm);
552 	}
553 
554 	if (IS_REACHABLE(CONFIG_THERMAL)) {
555 		fan->cdev = devm_thermal_of_cooling_device_register(dev,
556 			NULL, "mlxreg_fan", fan, &mlxreg_fan_cooling_ops);
557 		if (IS_ERR(fan->cdev)) {
558 			dev_err(dev, "Failed to register cooling device\n");
559 			return PTR_ERR(fan->cdev);
560 		}
561 	}
562 
563 	return 0;
564 }
565 
566 static struct platform_driver mlxreg_fan_driver = {
567 	.driver = {
568 	    .name = "mlxreg-fan",
569 	},
570 	.probe = mlxreg_fan_probe,
571 };
572 
573 module_platform_driver(mlxreg_fan_driver);
574 
575 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
576 MODULE_DESCRIPTION("Mellanox FAN driver");
577 MODULE_LICENSE("GPL");
578 MODULE_ALIAS("platform:mlxreg-fan");
579