xref: /openbmc/linux/drivers/thermal/st/stm_thermal.c (revision 03638e62)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
4  * Author: David Hernandez Sanchez <david.hernandezsanchez@st.com> for
5  * STMicroelectronics.
6  */
7 
8 #include <linux/clk.h>
9 #include <linux/clk-provider.h>
10 #include <linux/delay.h>
11 #include <linux/err.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/iopoll.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18 #include <linux/of_device.h>
19 #include <linux/platform_device.h>
20 #include <linux/thermal.h>
21 
22 #include "../thermal_core.h"
23 #include "../thermal_hwmon.h"
24 
25 /* DTS register offsets */
26 #define DTS_CFGR1_OFFSET	0x0
27 #define DTS_T0VALR1_OFFSET	0x8
28 #define DTS_RAMPVALR_OFFSET	0X10
29 #define DTS_ITR1_OFFSET		0x14
30 #define DTS_DR_OFFSET		0x1C
31 #define DTS_SR_OFFSET		0x20
32 #define DTS_ITENR_OFFSET	0x24
33 #define DTS_CIFR_OFFSET		0x28
34 
35 /* DTS_CFGR1 register mask definitions */
36 #define HSREF_CLK_DIV_MASK	GENMASK(30, 24)
37 #define TS1_SMP_TIME_MASK	GENMASK(19, 16)
38 #define TS1_INTRIG_SEL_MASK	GENMASK(11, 8)
39 
40 /* DTS_T0VALR1 register mask definitions */
41 #define TS1_T0_MASK		GENMASK(17, 16)
42 #define TS1_FMT0_MASK		GENMASK(15, 0)
43 
44 /* DTS_RAMPVALR register mask definitions */
45 #define TS1_RAMP_COEFF_MASK	GENMASK(15, 0)
46 
47 /* DTS_ITR1 register mask definitions */
48 #define TS1_HITTHD_MASK		GENMASK(31, 16)
49 #define TS1_LITTHD_MASK		GENMASK(15, 0)
50 
51 /* DTS_DR register mask definitions */
52 #define TS1_MFREQ_MASK		GENMASK(15, 0)
53 
54 /* Less significant bit position definitions */
55 #define TS1_T0_POS		16
56 #define TS1_SMP_TIME_POS	16
57 #define TS1_HITTHD_POS		16
58 #define HSREF_CLK_DIV_POS	24
59 
60 /* DTS_CFGR1 bit definitions */
61 #define TS1_EN			BIT(0)
62 #define TS1_START		BIT(4)
63 #define REFCLK_SEL		BIT(20)
64 #define REFCLK_LSE		REFCLK_SEL
65 #define Q_MEAS_OPT		BIT(21)
66 #define CALIBRATION_CONTROL	Q_MEAS_OPT
67 
68 /* DTS_SR bit definitions */
69 #define TS_RDY			BIT(15)
70 /* Bit definitions below are common for DTS_SR, DTS_ITENR and DTS_CIFR */
71 #define HIGH_THRESHOLD		BIT(2)
72 #define LOW_THRESHOLD		BIT(1)
73 
74 /* Constants */
75 #define ADJUST			100
76 #define ONE_MHZ			1000000
77 #define POLL_TIMEOUT		5000
78 #define STARTUP_TIME		40
79 #define TS1_T0_VAL0		30
80 #define TS1_T0_VAL1		130
81 #define NO_HW_TRIG		0
82 
83 /* The Thermal Framework expects millidegrees */
84 #define mcelsius(temp)		((temp) * 1000)
85 
86 /* The Sensor expects oC degrees */
87 #define celsius(temp)		((temp) / 1000)
88 
89 struct stm_thermal_sensor {
90 	struct device *dev;
91 	struct thermal_zone_device *th_dev;
92 	enum thermal_device_mode mode;
93 	struct clk *clk;
94 	int high_temp;
95 	int low_temp;
96 	int temp_critical;
97 	int temp_passive;
98 	unsigned int low_temp_enabled;
99 	int num_trips;
100 	int irq;
101 	unsigned int irq_enabled;
102 	void __iomem *base;
103 	int t0, fmt0, ramp_coeff;
104 };
105 
106 static irqreturn_t stm_thermal_alarm_irq(int irq, void *sdata)
107 {
108 	struct stm_thermal_sensor *sensor = sdata;
109 
110 	disable_irq_nosync(irq);
111 	sensor->irq_enabled = false;
112 
113 	return IRQ_WAKE_THREAD;
114 }
115 
116 static irqreturn_t stm_thermal_alarm_irq_thread(int irq, void *sdata)
117 {
118 	u32 value;
119 	struct stm_thermal_sensor *sensor = sdata;
120 
121 	/* read IT reason in SR and clear flags */
122 	value = readl_relaxed(sensor->base + DTS_SR_OFFSET);
123 
124 	if ((value & LOW_THRESHOLD) == LOW_THRESHOLD)
125 		writel_relaxed(LOW_THRESHOLD, sensor->base + DTS_CIFR_OFFSET);
126 
127 	if ((value & HIGH_THRESHOLD) == HIGH_THRESHOLD)
128 		writel_relaxed(HIGH_THRESHOLD, sensor->base + DTS_CIFR_OFFSET);
129 
130 	thermal_zone_device_update(sensor->th_dev, THERMAL_EVENT_UNSPECIFIED);
131 
132 	return IRQ_HANDLED;
133 }
134 
135 static int stm_sensor_power_on(struct stm_thermal_sensor *sensor)
136 {
137 	int ret;
138 	u32 value;
139 
140 	/* Enable sensor */
141 	value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
142 	value |= TS1_EN;
143 	writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);
144 
145 	/*
146 	 * The DTS block can be enabled by setting TSx_EN bit in
147 	 * DTS_CFGRx register. It requires a startup time of
148 	 * 40μs. Use 5 ms as arbitrary timeout.
149 	 */
150 	ret = readl_poll_timeout(sensor->base + DTS_SR_OFFSET,
151 				 value, (value & TS_RDY),
152 				 STARTUP_TIME, POLL_TIMEOUT);
153 	if (ret)
154 		return ret;
155 
156 	/* Start continuous measuring */
157 	value = readl_relaxed(sensor->base +
158 			      DTS_CFGR1_OFFSET);
159 	value |= TS1_START;
160 	writel_relaxed(value, sensor->base +
161 		       DTS_CFGR1_OFFSET);
162 
163 	return 0;
164 }
165 
166 static int stm_sensor_power_off(struct stm_thermal_sensor *sensor)
167 {
168 	u32 value;
169 
170 	/* Stop measuring */
171 	value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
172 	value &= ~TS1_START;
173 	writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);
174 
175 	/* Ensure stop is taken into account */
176 	usleep_range(STARTUP_TIME, POLL_TIMEOUT);
177 
178 	/* Disable sensor */
179 	value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
180 	value &= ~TS1_EN;
181 	writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);
182 
183 	/* Ensure disable is taken into account */
184 	return readl_poll_timeout(sensor->base + DTS_SR_OFFSET, value,
185 				  !(value & TS_RDY),
186 				  STARTUP_TIME, POLL_TIMEOUT);
187 }
188 
189 static int stm_thermal_calibration(struct stm_thermal_sensor *sensor)
190 {
191 	u32 value, clk_freq;
192 	u32 prescaler;
193 
194 	/* Figure out prescaler value for PCLK during calibration */
195 	clk_freq = clk_get_rate(sensor->clk);
196 	if (!clk_freq)
197 		return -EINVAL;
198 
199 	prescaler = 0;
200 	clk_freq /= ONE_MHZ;
201 	if (clk_freq) {
202 		while (prescaler <= clk_freq)
203 			prescaler++;
204 	}
205 
206 	value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
207 
208 	/* Clear prescaler */
209 	value &= ~HSREF_CLK_DIV_MASK;
210 
211 	/* Set prescaler. pclk_freq/prescaler < 1MHz */
212 	value |= (prescaler << HSREF_CLK_DIV_POS);
213 
214 	/* Select PCLK as reference clock */
215 	value &= ~REFCLK_SEL;
216 
217 	/* Set maximal sampling time for better precision */
218 	value |= TS1_SMP_TIME_MASK;
219 
220 	/* Measure with calibration */
221 	value &= ~CALIBRATION_CONTROL;
222 
223 	/* select trigger */
224 	value &= ~TS1_INTRIG_SEL_MASK;
225 	value |= NO_HW_TRIG;
226 
227 	writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);
228 
229 	return 0;
230 }
231 
232 /* Fill in DTS structure with factory sensor values */
233 static int stm_thermal_read_factory_settings(struct stm_thermal_sensor *sensor)
234 {
235 	/* Retrieve engineering calibration temperature */
236 	sensor->t0 = readl_relaxed(sensor->base + DTS_T0VALR1_OFFSET) &
237 					TS1_T0_MASK;
238 	if (!sensor->t0)
239 		sensor->t0 = TS1_T0_VAL0;
240 	else
241 		sensor->t0 = TS1_T0_VAL1;
242 
243 	/* Retrieve fmt0 and put it on Hz */
244 	sensor->fmt0 = ADJUST * (readl_relaxed(sensor->base +
245 				 DTS_T0VALR1_OFFSET) & TS1_FMT0_MASK);
246 
247 	/* Retrieve ramp coefficient */
248 	sensor->ramp_coeff = readl_relaxed(sensor->base + DTS_RAMPVALR_OFFSET) &
249 					   TS1_RAMP_COEFF_MASK;
250 
251 	if (!sensor->fmt0 || !sensor->ramp_coeff) {
252 		dev_err(sensor->dev, "%s: wrong setting\n", __func__);
253 		return -EINVAL;
254 	}
255 
256 	dev_dbg(sensor->dev, "%s: T0 = %doC, FMT0 = %dHz, RAMP_COEFF = %dHz/oC",
257 		__func__, sensor->t0, sensor->fmt0, sensor->ramp_coeff);
258 
259 	return 0;
260 }
261 
262 static int stm_thermal_calculate_threshold(struct stm_thermal_sensor *sensor,
263 					   int temp, u32 *th)
264 {
265 	int freqM;
266 	u32 sampling_time;
267 
268 	/* Retrieve the number of periods to sample */
269 	sampling_time = (readl_relaxed(sensor->base + DTS_CFGR1_OFFSET) &
270 			TS1_SMP_TIME_MASK) >> TS1_SMP_TIME_POS;
271 
272 	/* Figure out the CLK_PTAT frequency for a given temperature */
273 	freqM = ((temp - sensor->t0) * sensor->ramp_coeff)
274 		 + sensor->fmt0;
275 
276 	dev_dbg(sensor->dev, "%s: freqM for threshold = %d Hz",
277 		__func__, freqM);
278 
279 	/* Figure out the threshold sample number */
280 	*th = clk_get_rate(sensor->clk);
281 	if (!*th)
282 		return -EINVAL;
283 
284 	*th = *th / freqM;
285 
286 	*th *= sampling_time;
287 
288 	return 0;
289 }
290 
291 static int stm_thermal_set_threshold(struct stm_thermal_sensor *sensor)
292 {
293 	u32 value, th;
294 	int ret;
295 
296 	value = readl_relaxed(sensor->base + DTS_ITR1_OFFSET);
297 
298 	/* Erase threshold content */
299 	value &= ~(TS1_LITTHD_MASK | TS1_HITTHD_MASK);
300 
301 	/* Retrieve the sample threshold number th for a given temperature */
302 	ret = stm_thermal_calculate_threshold(sensor, sensor->high_temp, &th);
303 	if (ret)
304 		return ret;
305 
306 	value |= th & TS1_LITTHD_MASK;
307 
308 	if (sensor->low_temp_enabled) {
309 		/* Retrieve the sample threshold */
310 		ret = stm_thermal_calculate_threshold(sensor, sensor->low_temp,
311 						      &th);
312 		if (ret)
313 			return ret;
314 
315 		value |= (TS1_HITTHD_MASK  & (th << TS1_HITTHD_POS));
316 	}
317 
318 	/* Write value on the Low interrupt threshold */
319 	writel_relaxed(value, sensor->base + DTS_ITR1_OFFSET);
320 
321 	return 0;
322 }
323 
324 /* Disable temperature interrupt */
325 static int stm_disable_irq(struct stm_thermal_sensor *sensor)
326 {
327 	u32 value;
328 
329 	/* Disable IT generation for low and high thresholds */
330 	value = readl_relaxed(sensor->base + DTS_ITENR_OFFSET);
331 	writel_relaxed(value & ~(LOW_THRESHOLD | HIGH_THRESHOLD),
332 		       sensor->base + DTS_ITENR_OFFSET);
333 
334 	dev_dbg(sensor->dev, "%s: IT disabled on sensor side", __func__);
335 
336 	return 0;
337 }
338 
339 /* Enable temperature interrupt */
340 static int stm_enable_irq(struct stm_thermal_sensor *sensor)
341 {
342 	u32 value;
343 
344 	/*
345 	 * Code below enables High temperature threshold using a low threshold
346 	 * sampling value
347 	 */
348 
349 	/* Make sure LOW_THRESHOLD IT is clear before enabling */
350 	writel_relaxed(LOW_THRESHOLD, sensor->base + DTS_CIFR_OFFSET);
351 
352 	/* Enable IT generation for low threshold */
353 	value = readl_relaxed(sensor->base + DTS_ITENR_OFFSET);
354 	value |= LOW_THRESHOLD;
355 
356 	/* Enable the low temperature threshold if needed */
357 	if (sensor->low_temp_enabled) {
358 		/* Make sure HIGH_THRESHOLD IT is clear before enabling */
359 		writel_relaxed(HIGH_THRESHOLD, sensor->base + DTS_CIFR_OFFSET);
360 
361 		/* Enable IT generation for high threshold */
362 		value |= HIGH_THRESHOLD;
363 	}
364 
365 	/* Enable thresholds */
366 	writel_relaxed(value, sensor->base + DTS_ITENR_OFFSET);
367 
368 	dev_dbg(sensor->dev, "%s: IT enabled on sensor side", __func__);
369 
370 	return 0;
371 }
372 
373 static int stm_thermal_update_threshold(struct stm_thermal_sensor *sensor)
374 {
375 	int ret;
376 
377 	sensor->mode = THERMAL_DEVICE_DISABLED;
378 
379 	ret = stm_sensor_power_off(sensor);
380 	if (ret)
381 		return ret;
382 
383 	ret = stm_disable_irq(sensor);
384 	if (ret)
385 		return ret;
386 
387 	ret = stm_thermal_set_threshold(sensor);
388 	if (ret)
389 		return ret;
390 
391 	ret = stm_enable_irq(sensor);
392 	if (ret)
393 		return ret;
394 
395 	ret = stm_sensor_power_on(sensor);
396 	if (ret)
397 		return ret;
398 
399 	sensor->mode = THERMAL_DEVICE_ENABLED;
400 
401 	return 0;
402 }
403 
404 /* Callback to get temperature from HW */
405 static int stm_thermal_get_temp(void *data, int *temp)
406 {
407 	struct stm_thermal_sensor *sensor = data;
408 	u32 sampling_time;
409 	int freqM, ret;
410 
411 	if (sensor->mode != THERMAL_DEVICE_ENABLED)
412 		return -EAGAIN;
413 
414 	/* Retrieve the number of samples */
415 	ret = readl_poll_timeout(sensor->base + DTS_DR_OFFSET, freqM,
416 				 (freqM & TS1_MFREQ_MASK), STARTUP_TIME,
417 				 POLL_TIMEOUT);
418 
419 	if (ret)
420 		return ret;
421 
422 	if (!freqM)
423 		return -ENODATA;
424 
425 	/* Retrieve the number of periods sampled */
426 	sampling_time = (readl_relaxed(sensor->base + DTS_CFGR1_OFFSET) &
427 			TS1_SMP_TIME_MASK) >> TS1_SMP_TIME_POS;
428 
429 	/* Figure out the number of samples per period */
430 	freqM /= sampling_time;
431 
432 	/* Figure out the CLK_PTAT frequency */
433 	freqM = clk_get_rate(sensor->clk) / freqM;
434 	if (!freqM)
435 		return -EINVAL;
436 
437 	dev_dbg(sensor->dev, "%s: freqM=%d\n", __func__, freqM);
438 
439 	/* Figure out the temperature in mili celsius */
440 	*temp = mcelsius(sensor->t0 + ((freqM - sensor->fmt0) /
441 			 sensor->ramp_coeff));
442 
443 	dev_dbg(sensor->dev, "%s: temperature = %d millicelsius",
444 		__func__, *temp);
445 
446 	/* Update thresholds */
447 	if (sensor->num_trips > 1) {
448 		/* Update alarm threshold value to next higher trip point */
449 		if (sensor->high_temp == sensor->temp_passive &&
450 		    celsius(*temp) >= sensor->temp_passive) {
451 			sensor->high_temp = sensor->temp_critical;
452 			sensor->low_temp = sensor->temp_passive;
453 			sensor->low_temp_enabled = true;
454 			ret = stm_thermal_update_threshold(sensor);
455 			if (ret)
456 				return ret;
457 		}
458 
459 		if (sensor->high_temp == sensor->temp_critical &&
460 		    celsius(*temp) < sensor->temp_passive) {
461 			sensor->high_temp = sensor->temp_passive;
462 			sensor->low_temp_enabled = false;
463 			ret = stm_thermal_update_threshold(sensor);
464 			if (ret)
465 				return ret;
466 		}
467 
468 		/*
469 		 * Re-enable alarm IRQ if temperature below critical
470 		 * temperature
471 		 */
472 		if (!sensor->irq_enabled &&
473 		    (celsius(*temp) < sensor->temp_critical)) {
474 			sensor->irq_enabled = true;
475 			enable_irq(sensor->irq);
476 		}
477 	}
478 
479 	return 0;
480 }
481 
482 /* Registers DTS irq to be visible by GIC */
483 static int stm_register_irq(struct stm_thermal_sensor *sensor)
484 {
485 	struct device *dev = sensor->dev;
486 	struct platform_device *pdev = to_platform_device(dev);
487 	int ret;
488 
489 	sensor->irq = platform_get_irq(pdev, 0);
490 	if (sensor->irq < 0) {
491 		dev_err(dev, "%s: Unable to find IRQ\n", __func__);
492 		return sensor->irq;
493 	}
494 
495 	ret = devm_request_threaded_irq(dev, sensor->irq,
496 					stm_thermal_alarm_irq,
497 					stm_thermal_alarm_irq_thread,
498 					IRQF_ONESHOT,
499 					dev->driver->name, sensor);
500 	if (ret) {
501 		dev_err(dev, "%s: Failed to register IRQ %d\n", __func__,
502 			sensor->irq);
503 		return ret;
504 	}
505 
506 	sensor->irq_enabled = true;
507 
508 	dev_dbg(dev, "%s: thermal IRQ registered", __func__);
509 
510 	return 0;
511 }
512 
513 static int stm_thermal_sensor_off(struct stm_thermal_sensor *sensor)
514 {
515 	int ret;
516 
517 	ret = stm_sensor_power_off(sensor);
518 	if (ret)
519 		return ret;
520 
521 	clk_disable_unprepare(sensor->clk);
522 
523 	return 0;
524 }
525 
526 static int stm_thermal_prepare(struct stm_thermal_sensor *sensor)
527 {
528 	int ret;
529 	struct device *dev = sensor->dev;
530 
531 	ret = clk_prepare_enable(sensor->clk);
532 	if (ret)
533 		return ret;
534 
535 	ret = stm_thermal_read_factory_settings(sensor);
536 	if (ret)
537 		goto thermal_unprepare;
538 
539 	ret = stm_thermal_calibration(sensor);
540 	if (ret)
541 		goto thermal_unprepare;
542 
543 	/* Set threshold(s) for IRQ */
544 	ret = stm_thermal_set_threshold(sensor);
545 	if (ret)
546 		goto thermal_unprepare;
547 
548 	ret = stm_enable_irq(sensor);
549 	if (ret)
550 		goto thermal_unprepare;
551 
552 	ret = stm_sensor_power_on(sensor);
553 	if (ret) {
554 		dev_err(dev, "%s: failed to power on sensor\n", __func__);
555 		goto irq_disable;
556 	}
557 
558 	return 0;
559 
560 irq_disable:
561 	stm_disable_irq(sensor);
562 
563 thermal_unprepare:
564 	clk_disable_unprepare(sensor->clk);
565 
566 	return ret;
567 }
568 
569 #ifdef CONFIG_PM_SLEEP
570 static int stm_thermal_suspend(struct device *dev)
571 {
572 	int ret;
573 	struct stm_thermal_sensor *sensor = dev_get_drvdata(dev);
574 
575 	ret = stm_thermal_sensor_off(sensor);
576 	if (ret)
577 		return ret;
578 
579 	sensor->mode = THERMAL_DEVICE_DISABLED;
580 
581 	return 0;
582 }
583 
584 static int stm_thermal_resume(struct device *dev)
585 {
586 	int ret;
587 	struct stm_thermal_sensor *sensor = dev_get_drvdata(dev);
588 
589 	ret = stm_thermal_prepare(sensor);
590 	if (ret)
591 		return ret;
592 
593 	sensor->mode = THERMAL_DEVICE_ENABLED;
594 
595 	return 0;
596 }
597 #endif /* CONFIG_PM_SLEEP */
598 
599 SIMPLE_DEV_PM_OPS(stm_thermal_pm_ops, stm_thermal_suspend, stm_thermal_resume);
600 
601 static const struct thermal_zone_of_device_ops stm_tz_ops = {
602 	.get_temp	= stm_thermal_get_temp,
603 };
604 
605 static const struct of_device_id stm_thermal_of_match[] = {
606 		{ .compatible = "st,stm32-thermal"},
607 	{ /* sentinel */ }
608 };
609 MODULE_DEVICE_TABLE(of, stm_thermal_of_match);
610 
611 static int stm_thermal_probe(struct platform_device *pdev)
612 {
613 	struct stm_thermal_sensor *sensor;
614 	struct resource *res;
615 	const struct thermal_trip *trip;
616 	void __iomem *base;
617 	int ret, i;
618 
619 	if (!pdev->dev.of_node) {
620 		dev_err(&pdev->dev, "%s: device tree node not found\n",
621 			__func__);
622 		return -EINVAL;
623 	}
624 
625 	sensor = devm_kzalloc(&pdev->dev, sizeof(*sensor), GFP_KERNEL);
626 	if (!sensor)
627 		return -ENOMEM;
628 
629 	platform_set_drvdata(pdev, sensor);
630 
631 	sensor->dev = &pdev->dev;
632 
633 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
634 	base = devm_ioremap_resource(&pdev->dev, res);
635 	if (IS_ERR(base))
636 		return PTR_ERR(base);
637 
638 	/* Populate sensor */
639 	sensor->base = base;
640 
641 	sensor->clk = devm_clk_get(&pdev->dev, "pclk");
642 	if (IS_ERR(sensor->clk)) {
643 		dev_err(&pdev->dev, "%s: failed to fetch PCLK clock\n",
644 			__func__);
645 		return PTR_ERR(sensor->clk);
646 	}
647 
648 	/* Register IRQ into GIC */
649 	ret = stm_register_irq(sensor);
650 	if (ret)
651 		return ret;
652 
653 	sensor->th_dev = devm_thermal_zone_of_sensor_register(&pdev->dev, 0,
654 							      sensor,
655 							      &stm_tz_ops);
656 
657 	if (IS_ERR(sensor->th_dev)) {
658 		dev_err(&pdev->dev, "%s: thermal zone sensor registering KO\n",
659 			__func__);
660 		ret = PTR_ERR(sensor->th_dev);
661 		return ret;
662 	}
663 
664 	if (!sensor->th_dev->ops->get_crit_temp) {
665 		/* Critical point must be provided */
666 		ret = -EINVAL;
667 		goto err_tz;
668 	}
669 
670 	ret = sensor->th_dev->ops->get_crit_temp(sensor->th_dev,
671 			&sensor->temp_critical);
672 	if (ret) {
673 		dev_err(&pdev->dev,
674 			"Not able to read critical_temp: %d\n", ret);
675 		goto err_tz;
676 	}
677 
678 	sensor->temp_critical = celsius(sensor->temp_critical);
679 
680 	/* Set thresholds for IRQ */
681 	sensor->high_temp = sensor->temp_critical;
682 
683 	trip = of_thermal_get_trip_points(sensor->th_dev);
684 	sensor->num_trips = of_thermal_get_ntrips(sensor->th_dev);
685 
686 	/* Find out passive temperature if it exists */
687 	for (i = (sensor->num_trips - 1); i >= 0;  i--) {
688 		if (trip[i].type == THERMAL_TRIP_PASSIVE) {
689 			sensor->temp_passive = celsius(trip[i].temperature);
690 			/* Update high temperature threshold */
691 			sensor->high_temp = sensor->temp_passive;
692 			}
693 	}
694 
695 	/*
696 	 * Ensure low_temp_enabled flag is disabled.
697 	 * By disabling low_temp_enabled, low threshold IT will not be
698 	 * configured neither enabled because it is not needed as high
699 	 * threshold is set on the lowest temperature trip point after
700 	 * probe.
701 	 */
702 	sensor->low_temp_enabled = false;
703 
704 	/* Configure and enable HW sensor */
705 	ret = stm_thermal_prepare(sensor);
706 	if (ret) {
707 		dev_err(&pdev->dev,
708 			"Not able to enable sensor: %d\n", ret);
709 		goto err_tz;
710 	}
711 
712 	/*
713 	 * Thermal_zone doesn't enable hwmon as default,
714 	 * enable it here
715 	 */
716 	sensor->th_dev->tzp->no_hwmon = false;
717 	ret = thermal_add_hwmon_sysfs(sensor->th_dev);
718 	if (ret)
719 		goto err_tz;
720 
721 	sensor->mode = THERMAL_DEVICE_ENABLED;
722 
723 	dev_info(&pdev->dev, "%s: Driver initialized successfully\n",
724 		 __func__);
725 
726 	return 0;
727 
728 err_tz:
729 	thermal_zone_of_sensor_unregister(&pdev->dev, sensor->th_dev);
730 	return ret;
731 }
732 
733 static int stm_thermal_remove(struct platform_device *pdev)
734 {
735 	struct stm_thermal_sensor *sensor = platform_get_drvdata(pdev);
736 
737 	stm_thermal_sensor_off(sensor);
738 	thermal_remove_hwmon_sysfs(sensor->th_dev);
739 	thermal_zone_of_sensor_unregister(&pdev->dev, sensor->th_dev);
740 
741 	return 0;
742 }
743 
744 static struct platform_driver stm_thermal_driver = {
745 	.driver = {
746 		.name	= "stm_thermal",
747 		.pm     = &stm_thermal_pm_ops,
748 		.of_match_table = stm_thermal_of_match,
749 	},
750 	.probe		= stm_thermal_probe,
751 	.remove		= stm_thermal_remove,
752 };
753 module_platform_driver(stm_thermal_driver);
754 
755 MODULE_DESCRIPTION("STMicroelectronics STM32 Thermal Sensor Driver");
756 MODULE_AUTHOR("David Hernandez Sanchez <david.hernandezsanchez@st.com>");
757 MODULE_LICENSE("GPL v2");
758 MODULE_ALIAS("platform:stm_thermal");
759