xref: /openbmc/linux/drivers/thermal/imx_thermal.c (revision 6774def6)
1 /*
2  * Copyright 2013 Freescale Semiconductor, Inc.
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  */
9 
10 #include <linux/clk.h>
11 #include <linux/cpu_cooling.h>
12 #include <linux/cpufreq.h>
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/init.h>
16 #include <linux/interrupt.h>
17 #include <linux/io.h>
18 #include <linux/kernel.h>
19 #include <linux/mfd/syscon.h>
20 #include <linux/module.h>
21 #include <linux/of.h>
22 #include <linux/of_device.h>
23 #include <linux/platform_device.h>
24 #include <linux/regmap.h>
25 #include <linux/slab.h>
26 #include <linux/thermal.h>
27 #include <linux/types.h>
28 
29 #define REG_SET		0x4
30 #define REG_CLR		0x8
31 #define REG_TOG		0xc
32 
33 #define MISC0				0x0150
34 #define MISC0_REFTOP_SELBIASOFF		(1 << 3)
35 #define MISC1				0x0160
36 #define MISC1_IRQ_TEMPHIGH		(1 << 29)
37 /* Below LOW and PANIC bits are only for TEMPMON_IMX6SX */
38 #define MISC1_IRQ_TEMPLOW		(1 << 28)
39 #define MISC1_IRQ_TEMPPANIC		(1 << 27)
40 
41 #define TEMPSENSE0			0x0180
42 #define TEMPSENSE0_ALARM_VALUE_SHIFT	20
43 #define TEMPSENSE0_ALARM_VALUE_MASK	(0xfff << TEMPSENSE0_ALARM_VALUE_SHIFT)
44 #define TEMPSENSE0_TEMP_CNT_SHIFT	8
45 #define TEMPSENSE0_TEMP_CNT_MASK	(0xfff << TEMPSENSE0_TEMP_CNT_SHIFT)
46 #define TEMPSENSE0_FINISHED		(1 << 2)
47 #define TEMPSENSE0_MEASURE_TEMP		(1 << 1)
48 #define TEMPSENSE0_POWER_DOWN		(1 << 0)
49 
50 #define TEMPSENSE1			0x0190
51 #define TEMPSENSE1_MEASURE_FREQ		0xffff
52 /* Below TEMPSENSE2 is only for TEMPMON_IMX6SX */
53 #define TEMPSENSE2			0x0290
54 #define TEMPSENSE2_LOW_VALUE_SHIFT	0
55 #define TEMPSENSE2_LOW_VALUE_MASK	0xfff
56 #define TEMPSENSE2_PANIC_VALUE_SHIFT	16
57 #define TEMPSENSE2_PANIC_VALUE_MASK	0xfff0000
58 
59 #define OCOTP_ANA1			0x04e0
60 
61 /* The driver supports 1 passive trip point and 1 critical trip point */
62 enum imx_thermal_trip {
63 	IMX_TRIP_PASSIVE,
64 	IMX_TRIP_CRITICAL,
65 	IMX_TRIP_NUM,
66 };
67 
68 /*
69  * It defines the temperature in millicelsius for passive trip point
70  * that will trigger cooling action when crossed.
71  */
72 #define IMX_TEMP_PASSIVE		85000
73 
74 #define IMX_POLLING_DELAY		2000 /* millisecond */
75 #define IMX_PASSIVE_DELAY		1000
76 
77 #define FACTOR0				10000000
78 #define FACTOR1				15976
79 #define FACTOR2				4297157
80 
81 #define TEMPMON_IMX6Q			1
82 #define TEMPMON_IMX6SX			2
83 
84 struct thermal_soc_data {
85 	u32 version;
86 };
87 
88 static struct thermal_soc_data thermal_imx6q_data = {
89 	.version = TEMPMON_IMX6Q,
90 };
91 
92 static struct thermal_soc_data thermal_imx6sx_data = {
93 	.version = TEMPMON_IMX6SX,
94 };
95 
96 struct imx_thermal_data {
97 	struct thermal_zone_device *tz;
98 	struct thermal_cooling_device *cdev;
99 	enum thermal_device_mode mode;
100 	struct regmap *tempmon;
101 	u32 c1, c2; /* See formula in imx_get_sensor_data() */
102 	unsigned long temp_passive;
103 	unsigned long temp_critical;
104 	unsigned long alarm_temp;
105 	unsigned long last_temp;
106 	bool irq_enabled;
107 	int irq;
108 	struct clk *thermal_clk;
109 	const struct thermal_soc_data *socdata;
110 };
111 
112 static void imx_set_panic_temp(struct imx_thermal_data *data,
113 			       signed long panic_temp)
114 {
115 	struct regmap *map = data->tempmon;
116 	int critical_value;
117 
118 	critical_value = (data->c2 - panic_temp) / data->c1;
119 	regmap_write(map, TEMPSENSE2 + REG_CLR, TEMPSENSE2_PANIC_VALUE_MASK);
120 	regmap_write(map, TEMPSENSE2 + REG_SET, critical_value <<
121 			TEMPSENSE2_PANIC_VALUE_SHIFT);
122 }
123 
124 static void imx_set_alarm_temp(struct imx_thermal_data *data,
125 			       signed long alarm_temp)
126 {
127 	struct regmap *map = data->tempmon;
128 	int alarm_value;
129 
130 	data->alarm_temp = alarm_temp;
131 	alarm_value = (data->c2 - alarm_temp) / data->c1;
132 	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_ALARM_VALUE_MASK);
133 	regmap_write(map, TEMPSENSE0 + REG_SET, alarm_value <<
134 			TEMPSENSE0_ALARM_VALUE_SHIFT);
135 }
136 
137 static int imx_get_temp(struct thermal_zone_device *tz, unsigned long *temp)
138 {
139 	struct imx_thermal_data *data = tz->devdata;
140 	struct regmap *map = data->tempmon;
141 	unsigned int n_meas;
142 	bool wait;
143 	u32 val;
144 
145 	if (data->mode == THERMAL_DEVICE_ENABLED) {
146 		/* Check if a measurement is currently in progress */
147 		regmap_read(map, TEMPSENSE0, &val);
148 		wait = !(val & TEMPSENSE0_FINISHED);
149 	} else {
150 		/*
151 		 * Every time we measure the temperature, we will power on the
152 		 * temperature sensor, enable measurements, take a reading,
153 		 * disable measurements, power off the temperature sensor.
154 		 */
155 		regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
156 		regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
157 
158 		wait = true;
159 	}
160 
161 	/*
162 	 * According to the temp sensor designers, it may require up to ~17us
163 	 * to complete a measurement.
164 	 */
165 	if (wait)
166 		usleep_range(20, 50);
167 
168 	regmap_read(map, TEMPSENSE0, &val);
169 
170 	if (data->mode != THERMAL_DEVICE_ENABLED) {
171 		regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
172 		regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
173 	}
174 
175 	if ((val & TEMPSENSE0_FINISHED) == 0) {
176 		dev_dbg(&tz->device, "temp measurement never finished\n");
177 		return -EAGAIN;
178 	}
179 
180 	n_meas = (val & TEMPSENSE0_TEMP_CNT_MASK) >> TEMPSENSE0_TEMP_CNT_SHIFT;
181 
182 	/* See imx_get_sensor_data() for formula derivation */
183 	*temp = data->c2 - n_meas * data->c1;
184 
185 	/* Update alarm value to next higher trip point for TEMPMON_IMX6Q */
186 	if (data->socdata->version == TEMPMON_IMX6Q) {
187 		if (data->alarm_temp == data->temp_passive &&
188 			*temp >= data->temp_passive)
189 			imx_set_alarm_temp(data, data->temp_critical);
190 		if (data->alarm_temp == data->temp_critical &&
191 			*temp < data->temp_passive) {
192 			imx_set_alarm_temp(data, data->temp_passive);
193 			dev_dbg(&tz->device, "thermal alarm off: T < %lu\n",
194 				data->alarm_temp / 1000);
195 		}
196 	}
197 
198 	if (*temp != data->last_temp) {
199 		dev_dbg(&tz->device, "millicelsius: %ld\n", *temp);
200 		data->last_temp = *temp;
201 	}
202 
203 	/* Reenable alarm IRQ if temperature below alarm temperature */
204 	if (!data->irq_enabled && *temp < data->alarm_temp) {
205 		data->irq_enabled = true;
206 		enable_irq(data->irq);
207 	}
208 
209 	return 0;
210 }
211 
212 static int imx_get_mode(struct thermal_zone_device *tz,
213 			enum thermal_device_mode *mode)
214 {
215 	struct imx_thermal_data *data = tz->devdata;
216 
217 	*mode = data->mode;
218 
219 	return 0;
220 }
221 
222 static int imx_set_mode(struct thermal_zone_device *tz,
223 			enum thermal_device_mode mode)
224 {
225 	struct imx_thermal_data *data = tz->devdata;
226 	struct regmap *map = data->tempmon;
227 
228 	if (mode == THERMAL_DEVICE_ENABLED) {
229 		tz->polling_delay = IMX_POLLING_DELAY;
230 		tz->passive_delay = IMX_PASSIVE_DELAY;
231 
232 		regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
233 		regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
234 
235 		if (!data->irq_enabled) {
236 			data->irq_enabled = true;
237 			enable_irq(data->irq);
238 		}
239 	} else {
240 		regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
241 		regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
242 
243 		tz->polling_delay = 0;
244 		tz->passive_delay = 0;
245 
246 		if (data->irq_enabled) {
247 			disable_irq(data->irq);
248 			data->irq_enabled = false;
249 		}
250 	}
251 
252 	data->mode = mode;
253 	thermal_zone_device_update(tz);
254 
255 	return 0;
256 }
257 
258 static int imx_get_trip_type(struct thermal_zone_device *tz, int trip,
259 			     enum thermal_trip_type *type)
260 {
261 	*type = (trip == IMX_TRIP_PASSIVE) ? THERMAL_TRIP_PASSIVE :
262 					     THERMAL_TRIP_CRITICAL;
263 	return 0;
264 }
265 
266 static int imx_get_crit_temp(struct thermal_zone_device *tz,
267 			     unsigned long *temp)
268 {
269 	struct imx_thermal_data *data = tz->devdata;
270 
271 	*temp = data->temp_critical;
272 	return 0;
273 }
274 
275 static int imx_get_trip_temp(struct thermal_zone_device *tz, int trip,
276 			     unsigned long *temp)
277 {
278 	struct imx_thermal_data *data = tz->devdata;
279 
280 	*temp = (trip == IMX_TRIP_PASSIVE) ? data->temp_passive :
281 					     data->temp_critical;
282 	return 0;
283 }
284 
285 static int imx_set_trip_temp(struct thermal_zone_device *tz, int trip,
286 			     unsigned long temp)
287 {
288 	struct imx_thermal_data *data = tz->devdata;
289 
290 	if (trip == IMX_TRIP_CRITICAL)
291 		return -EPERM;
292 
293 	if (temp > IMX_TEMP_PASSIVE)
294 		return -EINVAL;
295 
296 	data->temp_passive = temp;
297 
298 	imx_set_alarm_temp(data, temp);
299 
300 	return 0;
301 }
302 
303 static int imx_bind(struct thermal_zone_device *tz,
304 		    struct thermal_cooling_device *cdev)
305 {
306 	int ret;
307 
308 	ret = thermal_zone_bind_cooling_device(tz, IMX_TRIP_PASSIVE, cdev,
309 					       THERMAL_NO_LIMIT,
310 					       THERMAL_NO_LIMIT);
311 	if (ret) {
312 		dev_err(&tz->device,
313 			"binding zone %s with cdev %s failed:%d\n",
314 			tz->type, cdev->type, ret);
315 		return ret;
316 	}
317 
318 	return 0;
319 }
320 
321 static int imx_unbind(struct thermal_zone_device *tz,
322 		      struct thermal_cooling_device *cdev)
323 {
324 	int ret;
325 
326 	ret = thermal_zone_unbind_cooling_device(tz, IMX_TRIP_PASSIVE, cdev);
327 	if (ret) {
328 		dev_err(&tz->device,
329 			"unbinding zone %s with cdev %s failed:%d\n",
330 			tz->type, cdev->type, ret);
331 		return ret;
332 	}
333 
334 	return 0;
335 }
336 
337 static struct thermal_zone_device_ops imx_tz_ops = {
338 	.bind = imx_bind,
339 	.unbind = imx_unbind,
340 	.get_temp = imx_get_temp,
341 	.get_mode = imx_get_mode,
342 	.set_mode = imx_set_mode,
343 	.get_trip_type = imx_get_trip_type,
344 	.get_trip_temp = imx_get_trip_temp,
345 	.get_crit_temp = imx_get_crit_temp,
346 	.set_trip_temp = imx_set_trip_temp,
347 };
348 
349 static int imx_get_sensor_data(struct platform_device *pdev)
350 {
351 	struct imx_thermal_data *data = platform_get_drvdata(pdev);
352 	struct regmap *map;
353 	int t1, n1;
354 	int ret;
355 	u32 val;
356 	u64 temp64;
357 
358 	map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
359 					      "fsl,tempmon-data");
360 	if (IS_ERR(map)) {
361 		ret = PTR_ERR(map);
362 		dev_err(&pdev->dev, "failed to get sensor regmap: %d\n", ret);
363 		return ret;
364 	}
365 
366 	ret = regmap_read(map, OCOTP_ANA1, &val);
367 	if (ret) {
368 		dev_err(&pdev->dev, "failed to read sensor data: %d\n", ret);
369 		return ret;
370 	}
371 
372 	if (val == 0 || val == ~0) {
373 		dev_err(&pdev->dev, "invalid sensor calibration data\n");
374 		return -EINVAL;
375 	}
376 
377 	/*
378 	 * Sensor data layout:
379 	 *   [31:20] - sensor value @ 25C
380 	 * Use universal formula now and only need sensor value @ 25C
381 	 * slope = 0.4297157 - (0.0015976 * 25C fuse)
382 	 */
383 	n1 = val >> 20;
384 	t1 = 25; /* t1 always 25C */
385 
386 	/*
387 	 * Derived from linear interpolation:
388 	 * slope = 0.4297157 - (0.0015976 * 25C fuse)
389 	 * slope = (FACTOR2 - FACTOR1 * n1) / FACTOR0
390 	 * (Nmeas - n1) / (Tmeas - t1) = slope
391 	 * We want to reduce this down to the minimum computation necessary
392 	 * for each temperature read.  Also, we want Tmeas in millicelsius
393 	 * and we don't want to lose precision from integer division. So...
394 	 * Tmeas = (Nmeas - n1) / slope + t1
395 	 * milli_Tmeas = 1000 * (Nmeas - n1) / slope + 1000 * t1
396 	 * milli_Tmeas = -1000 * (n1 - Nmeas) / slope + 1000 * t1
397 	 * Let constant c1 = (-1000 / slope)
398 	 * milli_Tmeas = (n1 - Nmeas) * c1 + 1000 * t1
399 	 * Let constant c2 = n1 *c1 + 1000 * t1
400 	 * milli_Tmeas = c2 - Nmeas * c1
401 	 */
402 	temp64 = FACTOR0;
403 	temp64 *= 1000;
404 	do_div(temp64, FACTOR1 * n1 - FACTOR2);
405 	data->c1 = temp64;
406 	data->c2 = n1 * data->c1 + 1000 * t1;
407 
408 	/*
409 	 * Set the default passive cooling trip point,
410 	 * can be changed from userspace.
411 	 */
412 	data->temp_passive = IMX_TEMP_PASSIVE;
413 
414 	/*
415 	 * The maximum die temperature set to 20 C higher than
416 	 * IMX_TEMP_PASSIVE.
417 	 */
418 	data->temp_critical = 1000 * 20 + data->temp_passive;
419 
420 	return 0;
421 }
422 
423 static irqreturn_t imx_thermal_alarm_irq(int irq, void *dev)
424 {
425 	struct imx_thermal_data *data = dev;
426 
427 	disable_irq_nosync(irq);
428 	data->irq_enabled = false;
429 
430 	return IRQ_WAKE_THREAD;
431 }
432 
433 static irqreturn_t imx_thermal_alarm_irq_thread(int irq, void *dev)
434 {
435 	struct imx_thermal_data *data = dev;
436 
437 	dev_dbg(&data->tz->device, "THERMAL ALARM: T > %lu\n",
438 		data->alarm_temp / 1000);
439 
440 	thermal_zone_device_update(data->tz);
441 
442 	return IRQ_HANDLED;
443 }
444 
445 static const struct of_device_id of_imx_thermal_match[] = {
446 	{ .compatible = "fsl,imx6q-tempmon", .data = &thermal_imx6q_data, },
447 	{ .compatible = "fsl,imx6sx-tempmon", .data = &thermal_imx6sx_data, },
448 	{ /* end */ }
449 };
450 MODULE_DEVICE_TABLE(of, of_imx_thermal_match);
451 
452 static int imx_thermal_probe(struct platform_device *pdev)
453 {
454 	const struct of_device_id *of_id =
455 		of_match_device(of_imx_thermal_match, &pdev->dev);
456 	struct imx_thermal_data *data;
457 	struct cpumask clip_cpus;
458 	struct regmap *map;
459 	int measure_freq;
460 	int ret;
461 
462 	if (!cpufreq_get_current_driver()) {
463 		dev_dbg(&pdev->dev, "no cpufreq driver!");
464 		return -EPROBE_DEFER;
465 	}
466 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
467 	if (!data)
468 		return -ENOMEM;
469 
470 	map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "fsl,tempmon");
471 	if (IS_ERR(map)) {
472 		ret = PTR_ERR(map);
473 		dev_err(&pdev->dev, "failed to get tempmon regmap: %d\n", ret);
474 		return ret;
475 	}
476 	data->tempmon = map;
477 
478 	data->socdata = of_id->data;
479 
480 	/* make sure the IRQ flag is clear before enabling irq on i.MX6SX */
481 	if (data->socdata->version == TEMPMON_IMX6SX) {
482 		regmap_write(map, MISC1 + REG_CLR, MISC1_IRQ_TEMPHIGH |
483 			MISC1_IRQ_TEMPLOW | MISC1_IRQ_TEMPPANIC);
484 		/*
485 		 * reset value of LOW ALARM is incorrect, set it to lowest
486 		 * value to avoid false trigger of low alarm.
487 		 */
488 		regmap_write(map, TEMPSENSE2 + REG_SET,
489 			TEMPSENSE2_LOW_VALUE_MASK);
490 	}
491 
492 	data->irq = platform_get_irq(pdev, 0);
493 	if (data->irq < 0)
494 		return data->irq;
495 
496 	ret = devm_request_threaded_irq(&pdev->dev, data->irq,
497 			imx_thermal_alarm_irq, imx_thermal_alarm_irq_thread,
498 			0, "imx_thermal", data);
499 	if (ret < 0) {
500 		dev_err(&pdev->dev, "failed to request alarm irq: %d\n", ret);
501 		return ret;
502 	}
503 
504 	platform_set_drvdata(pdev, data);
505 
506 	ret = imx_get_sensor_data(pdev);
507 	if (ret) {
508 		dev_err(&pdev->dev, "failed to get sensor data\n");
509 		return ret;
510 	}
511 
512 	/* Make sure sensor is in known good state for measurements */
513 	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
514 	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
515 	regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
516 	regmap_write(map, MISC0 + REG_SET, MISC0_REFTOP_SELBIASOFF);
517 	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
518 
519 	cpumask_set_cpu(0, &clip_cpus);
520 	data->cdev = cpufreq_cooling_register(&clip_cpus);
521 	if (IS_ERR(data->cdev)) {
522 		ret = PTR_ERR(data->cdev);
523 		dev_err(&pdev->dev,
524 			"failed to register cpufreq cooling device: %d\n", ret);
525 		return ret;
526 	}
527 
528 	data->thermal_clk = devm_clk_get(&pdev->dev, NULL);
529 	if (IS_ERR(data->thermal_clk)) {
530 		ret = PTR_ERR(data->thermal_clk);
531 		if (ret != -EPROBE_DEFER)
532 			dev_err(&pdev->dev,
533 				"failed to get thermal clk: %d\n", ret);
534 		cpufreq_cooling_unregister(data->cdev);
535 		return ret;
536 	}
537 
538 	/*
539 	 * Thermal sensor needs clk on to get correct value, normally
540 	 * we should enable its clk before taking measurement and disable
541 	 * clk after measurement is done, but if alarm function is enabled,
542 	 * hardware will auto measure the temperature periodically, so we
543 	 * need to keep the clk always on for alarm function.
544 	 */
545 	ret = clk_prepare_enable(data->thermal_clk);
546 	if (ret) {
547 		dev_err(&pdev->dev, "failed to enable thermal clk: %d\n", ret);
548 		cpufreq_cooling_unregister(data->cdev);
549 		return ret;
550 	}
551 
552 	data->tz = thermal_zone_device_register("imx_thermal_zone",
553 						IMX_TRIP_NUM,
554 						BIT(IMX_TRIP_PASSIVE), data,
555 						&imx_tz_ops, NULL,
556 						IMX_PASSIVE_DELAY,
557 						IMX_POLLING_DELAY);
558 	if (IS_ERR(data->tz)) {
559 		ret = PTR_ERR(data->tz);
560 		dev_err(&pdev->dev,
561 			"failed to register thermal zone device %d\n", ret);
562 		clk_disable_unprepare(data->thermal_clk);
563 		cpufreq_cooling_unregister(data->cdev);
564 		return ret;
565 	}
566 
567 	/* Enable measurements at ~ 10 Hz */
568 	regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
569 	measure_freq = DIV_ROUND_UP(32768, 10); /* 10 Hz */
570 	regmap_write(map, TEMPSENSE1 + REG_SET, measure_freq);
571 	imx_set_alarm_temp(data, data->temp_passive);
572 
573 	if (data->socdata->version == TEMPMON_IMX6SX)
574 		imx_set_panic_temp(data, data->temp_critical);
575 
576 	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
577 	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
578 
579 	data->irq_enabled = true;
580 	data->mode = THERMAL_DEVICE_ENABLED;
581 
582 	return 0;
583 }
584 
585 static int imx_thermal_remove(struct platform_device *pdev)
586 {
587 	struct imx_thermal_data *data = platform_get_drvdata(pdev);
588 	struct regmap *map = data->tempmon;
589 
590 	/* Disable measurements */
591 	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
592 	if (!IS_ERR(data->thermal_clk))
593 		clk_disable_unprepare(data->thermal_clk);
594 
595 	thermal_zone_device_unregister(data->tz);
596 	cpufreq_cooling_unregister(data->cdev);
597 
598 	return 0;
599 }
600 
601 #ifdef CONFIG_PM_SLEEP
602 static int imx_thermal_suspend(struct device *dev)
603 {
604 	struct imx_thermal_data *data = dev_get_drvdata(dev);
605 	struct regmap *map = data->tempmon;
606 
607 	/*
608 	 * Need to disable thermal sensor, otherwise, when thermal core
609 	 * try to get temperature before thermal sensor resume, a wrong
610 	 * temperature will be read as the thermal sensor is powered
611 	 * down.
612 	 */
613 	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
614 	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
615 	data->mode = THERMAL_DEVICE_DISABLED;
616 
617 	return 0;
618 }
619 
620 static int imx_thermal_resume(struct device *dev)
621 {
622 	struct imx_thermal_data *data = dev_get_drvdata(dev);
623 	struct regmap *map = data->tempmon;
624 
625 	/* Enabled thermal sensor after resume */
626 	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
627 	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);
628 	data->mode = THERMAL_DEVICE_ENABLED;
629 
630 	return 0;
631 }
632 #endif
633 
634 static SIMPLE_DEV_PM_OPS(imx_thermal_pm_ops,
635 			 imx_thermal_suspend, imx_thermal_resume);
636 
637 static struct platform_driver imx_thermal = {
638 	.driver = {
639 		.name	= "imx_thermal",
640 		.owner  = THIS_MODULE,
641 		.pm	= &imx_thermal_pm_ops,
642 		.of_match_table = of_imx_thermal_match,
643 	},
644 	.probe		= imx_thermal_probe,
645 	.remove		= imx_thermal_remove,
646 };
647 module_platform_driver(imx_thermal);
648 
649 MODULE_AUTHOR("Freescale Semiconductor, Inc.");
650 MODULE_DESCRIPTION("Thermal driver for Freescale i.MX SoCs");
651 MODULE_LICENSE("GPL v2");
652 MODULE_ALIAS("platform:imx-thermal");
653