summaryrefslogtreecommitdiff
path: root/drivers/thermal/imx_thermal.c
blob: 1d6c801c1eb979d36d4a43b5ab7f1a1377ee3bbe (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
/*
 * Copyright 2013 Freescale Semiconductor, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/cpu_cooling.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/thermal.h>
#include <linux/types.h>

#define REG_SET		0x4
#define REG_CLR		0x8
#define REG_TOG		0xc

#define MISC0				0x0150
#define MISC0_REFTOP_SELBIASOFF		(1 << 3)

#define TEMPSENSE0			0x0180
#define TEMPSENSE0_ALARM_VALUE_SHIFT	20
#define TEMPSENSE0_ALARM_VALUE_MASK	(0xfff << TEMPSENSE0_ALARM_VALUE_SHIFT)
#define TEMPSENSE0_TEMP_CNT_SHIFT	8
#define TEMPSENSE0_TEMP_CNT_MASK	(0xfff << TEMPSENSE0_TEMP_CNT_SHIFT)
#define TEMPSENSE0_FINISHED		(1 << 2)
#define TEMPSENSE0_MEASURE_TEMP		(1 << 1)
#define TEMPSENSE0_POWER_DOWN		(1 << 0)

#define TEMPSENSE1			0x0190
#define TEMPSENSE1_MEASURE_FREQ		0xffff

#define OCOTP_ANA1			0x04e0

/* The driver supports 1 passive trip point and 1 critical trip point */
enum imx_thermal_trip {
	IMX_TRIP_PASSIVE,
	IMX_TRIP_CRITICAL,
	IMX_TRIP_NUM,
};

/*
 * It defines the temperature in millicelsius for passive trip point
 * that will trigger cooling action when crossed.
 */
#define IMX_TEMP_PASSIVE		85000

#define IMX_POLLING_DELAY		2000 /* millisecond */
#define IMX_PASSIVE_DELAY		1000

struct imx_thermal_data {
	struct thermal_zone_device *tz;
	struct thermal_cooling_device *cdev;
	enum thermal_device_mode mode;
	struct regmap *tempmon;
	int c1, c2; /* See formula in imx_get_sensor_data() */
	unsigned long temp_passive;
	unsigned long temp_critical;
	unsigned long alarm_temp;
	unsigned long last_temp;
	bool irq_enabled;
	int irq;
};

static void imx_set_alarm_temp(struct imx_thermal_data *data,
			       signed long alarm_temp)
{
	struct regmap *map = data->tempmon;
	int alarm_value;

	data->alarm_temp = alarm_temp;
	alarm_value = (alarm_temp - data->c2) / data->c1;
	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_ALARM_VALUE_MASK);
	regmap_write(map, TEMPSENSE0 + REG_SET, alarm_value <<
			TEMPSENSE0_ALARM_VALUE_SHIFT);
}

static int imx_get_temp(struct thermal_zone_device *tz, unsigned long *temp)
{
	struct imx_thermal_data *data = tz->devdata;
	struct regmap *map = data->tempmon;
	unsigned int n_meas;
	bool wait;
	u32 val;

	if (data->mode == THERMAL_DEVICE_ENABLED) {
		/* Check if a measurement is currently in progress */
		regmap_read(map, TEMPSENSE0, &val);
		wait = !(val & TEMPSENSE0_FINISHED);
	} else {
		/*
		 * Every time we measure the temperature, we will power on the
		 * temperature sensor, enable measurements, take a reading,
		 * disable measurements, power off the temperature sensor.
		 */
		regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
		regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);

		wait = true;
	}

	/*
	 * According to the temp sensor designers, it may require up to ~17us
	 * to complete a measurement.
	 */
	if (wait)
		usleep_range(20, 50);

	regmap_read(map, TEMPSENSE0, &val);

	if (data->mode != THERMAL_DEVICE_ENABLED) {
		regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
		regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);
	}

	if ((val & TEMPSENSE0_FINISHED) == 0) {
		dev_dbg(&tz->device, "temp measurement never finished\n");
		return -EAGAIN;
	}

	n_meas = (val & TEMPSENSE0_TEMP_CNT_MASK) >> TEMPSENSE0_TEMP_CNT_SHIFT;

	/* See imx_get_sensor_data() for formula derivation */
	*temp = data->c2 + data->c1 * n_meas;

	/* Update alarm value to next higher trip point */
	if (data->alarm_temp == data->temp_passive && *temp >= data->temp_passive)
		imx_set_alarm_temp(data, data->temp_critical);
	if (data->alarm_temp == data->temp_critical && *temp < data->temp_passive) {
		imx_set_alarm_temp(data, data->temp_passive);
		dev_dbg(&tz->device, "thermal alarm off: T < %lu\n",
			data->alarm_temp / 1000);
	}

	if (*temp != data->last_temp) {
		dev_dbg(&tz->device, "millicelsius: %ld\n", *temp);
		data->last_temp = *temp;
	}

	/* Reenable alarm IRQ if temperature below alarm temperature */
	if (!data->irq_enabled && *temp < data->alarm_temp) {
		data->irq_enabled = true;
		enable_irq(data->irq);
	}

	return 0;
}

static int imx_get_mode(struct thermal_zone_device *tz,
			enum thermal_device_mode *mode)
{
	struct imx_thermal_data *data = tz->devdata;

	*mode = data->mode;

	return 0;
}

static int imx_set_mode(struct thermal_zone_device *tz,
			enum thermal_device_mode mode)
{
	struct imx_thermal_data *data = tz->devdata;
	struct regmap *map = data->tempmon;

	if (mode == THERMAL_DEVICE_ENABLED) {
		tz->polling_delay = IMX_POLLING_DELAY;
		tz->passive_delay = IMX_PASSIVE_DELAY;

		regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
		regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);

		if (!data->irq_enabled) {
			data->irq_enabled = true;
			enable_irq(data->irq);
		}
	} else {
		regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
		regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);

		tz->polling_delay = 0;
		tz->passive_delay = 0;

		if (data->irq_enabled) {
			disable_irq(data->irq);
			data->irq_enabled = false;
		}
	}

	data->mode = mode;
	thermal_zone_device_update(tz);

	return 0;
}

static int imx_get_trip_type(struct thermal_zone_device *tz, int trip,
			     enum thermal_trip_type *type)
{
	*type = (trip == IMX_TRIP_PASSIVE) ? THERMAL_TRIP_PASSIVE :
					     THERMAL_TRIP_CRITICAL;
	return 0;
}

static int imx_get_crit_temp(struct thermal_zone_device *tz,
			     unsigned long *temp)
{
	struct imx_thermal_data *data = tz->devdata;

	*temp = data->temp_critical;
	return 0;
}

static int imx_get_trip_temp(struct thermal_zone_device *tz, int trip,
			     unsigned long *temp)
{
	struct imx_thermal_data *data = tz->devdata;

	*temp = (trip == IMX_TRIP_PASSIVE) ? data->temp_passive :
					     data->temp_critical;
	return 0;
}

static int imx_set_trip_temp(struct thermal_zone_device *tz, int trip,
			     unsigned long temp)
{
	struct imx_thermal_data *data = tz->devdata;

	if (trip == IMX_TRIP_CRITICAL)
		return -EPERM;

	if (temp > IMX_TEMP_PASSIVE)
		return -EINVAL;

	data->temp_passive = temp;

	imx_set_alarm_temp(data, temp);

	return 0;
}

static int imx_bind(struct thermal_zone_device *tz,
		    struct thermal_cooling_device *cdev)
{
	int ret;

	ret = thermal_zone_bind_cooling_device(tz, IMX_TRIP_PASSIVE, cdev,
					       THERMAL_NO_LIMIT,
					       THERMAL_NO_LIMIT);
	if (ret) {
		dev_err(&tz->device,
			"binding zone %s with cdev %s failed:%d\n",
			tz->type, cdev->type, ret);
		return ret;
	}

	return 0;
}

static int imx_unbind(struct thermal_zone_device *tz,
		      struct thermal_cooling_device *cdev)
{
	int ret;

	ret = thermal_zone_unbind_cooling_device(tz, IMX_TRIP_PASSIVE, cdev);
	if (ret) {
		dev_err(&tz->device,
			"unbinding zone %s with cdev %s failed:%d\n",
			tz->type, cdev->type, ret);
		return ret;
	}

	return 0;
}

static const struct thermal_zone_device_ops imx_tz_ops = {
	.bind = imx_bind,
	.unbind = imx_unbind,
	.get_temp = imx_get_temp,
	.get_mode = imx_get_mode,
	.set_mode = imx_set_mode,
	.get_trip_type = imx_get_trip_type,
	.get_trip_temp = imx_get_trip_temp,
	.get_crit_temp = imx_get_crit_temp,
	.set_trip_temp = imx_set_trip_temp,
};

static int imx_get_sensor_data(struct platform_device *pdev)
{
	struct imx_thermal_data *data = platform_get_drvdata(pdev);
	struct regmap *map;
	int t1, t2, n1, n2;
	int ret;
	u32 val;

	map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
					      "fsl,tempmon-data");
	if (IS_ERR(map)) {
		ret = PTR_ERR(map);
		dev_err(&pdev->dev, "failed to get sensor regmap: %d\n", ret);
		return ret;
	}

	ret = regmap_read(map, OCOTP_ANA1, &val);
	if (ret) {
		dev_err(&pdev->dev, "failed to read sensor data: %d\n", ret);
		return ret;
	}

	if (val == 0 || val == ~0) {
		dev_err(&pdev->dev, "invalid sensor calibration data\n");
		return -EINVAL;
	}

	/*
	 * Sensor data layout:
	 *   [31:20] - sensor value @ 25C
	 *    [19:8] - sensor value of hot
	 *     [7:0] - hot temperature value
	 */
	n1 = val >> 20;
	n2 = (val & 0xfff00) >> 8;
	t2 = val & 0xff;
	t1 = 25; /* t1 always 25C */

	/*
	 * Derived from linear interpolation,
	 * Tmeas = T2 + (Nmeas - N2) * (T1 - T2) / (N1 - N2)
	 * We want to reduce this down to the minimum computation necessary
	 * for each temperature read.  Also, we want Tmeas in millicelsius
	 * and we don't want to lose precision from integer division. So...
	 * milli_Tmeas = 1000 * T2 + 1000 * (Nmeas - N2) * (T1 - T2) / (N1 - N2)
	 * Let constant c1 = 1000 * (T1 - T2) / (N1 - N2)
	 * milli_Tmeas = (1000 * T2) + c1 * (Nmeas - N2)
	 * milli_Tmeas = (1000 * T2) + (c1 * Nmeas) - (c1 * N2)
	 * Let constant c2 = (1000 * T2) - (c1 * N2)
	 * milli_Tmeas = c2 + (c1 * Nmeas)
	 */
	data->c1 = 1000 * (t1 - t2) / (n1 - n2);
	data->c2 = 1000 * t2 - data->c1 * n2;

	/*
	 * Set the default passive cooling trip point to 20 °C below the
	 * maximum die temperature. Can be changed from userspace.
	 */
	data->temp_passive = 1000 * (t2 - 20);

	/*
	 * The maximum die temperature is t2, let's give 5 °C cushion
	 * for noise and possible temperature rise between measurements.
	 */
	data->temp_critical = 1000 * (t2 - 5);

	return 0;
}

static irqreturn_t imx_thermal_alarm_irq(int irq, void *dev)
{
	struct imx_thermal_data *data = dev;

	disable_irq_nosync(irq);
	data->irq_enabled = false;

	return IRQ_WAKE_THREAD;
}

static irqreturn_t imx_thermal_alarm_irq_thread(int irq, void *dev)
{
	struct imx_thermal_data *data = dev;

	dev_dbg(&data->tz->device, "THERMAL ALARM: T > %lu\n",
		data->alarm_temp / 1000);

	thermal_zone_device_update(data->tz);

	return IRQ_HANDLED;
}

static int imx_thermal_probe(struct platform_device *pdev)
{
	struct imx_thermal_data *data;
	struct cpumask clip_cpus;
	struct regmap *map;
	int measure_freq;
	int ret;

	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	map = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "fsl,tempmon");
	if (IS_ERR(map)) {
		ret = PTR_ERR(map);
		dev_err(&pdev->dev, "failed to get tempmon regmap: %d\n", ret);
		return ret;
	}
	data->tempmon = map;

	data->irq = platform_get_irq(pdev, 0);
	if (data->irq < 0)
		return data->irq;

	ret = devm_request_threaded_irq(&pdev->dev, data->irq,
			imx_thermal_alarm_irq, imx_thermal_alarm_irq_thread,
			0, "imx_thermal", data);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to request alarm irq: %d\n", ret);
		return ret;
	}

	platform_set_drvdata(pdev, data);

	ret = imx_get_sensor_data(pdev);
	if (ret) {
		dev_err(&pdev->dev, "failed to get sensor data\n");
		return ret;
	}

	/* Make sure sensor is in known good state for measurements */
	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_MEASURE_TEMP);
	regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
	regmap_write(map, MISC0 + REG_SET, MISC0_REFTOP_SELBIASOFF);
	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);

	cpumask_set_cpu(0, &clip_cpus);
	data->cdev = cpufreq_cooling_register(&clip_cpus);
	if (IS_ERR(data->cdev)) {
		ret = PTR_ERR(data->cdev);
		dev_err(&pdev->dev,
			"failed to register cpufreq cooling device: %d\n", ret);
		return ret;
	}

	data->tz = thermal_zone_device_register("imx_thermal_zone",
						IMX_TRIP_NUM,
						BIT(IMX_TRIP_PASSIVE), data,
						&imx_tz_ops, NULL,
						IMX_PASSIVE_DELAY,
						IMX_POLLING_DELAY);
	if (IS_ERR(data->tz)) {
		ret = PTR_ERR(data->tz);
		dev_err(&pdev->dev,
			"failed to register thermal zone device %d\n", ret);
		cpufreq_cooling_unregister(data->cdev);
		return ret;
	}

	/* Enable measurements at ~ 10 Hz */
	regmap_write(map, TEMPSENSE1 + REG_CLR, TEMPSENSE1_MEASURE_FREQ);
	measure_freq = DIV_ROUND_UP(32768, 10); /* 10 Hz */
	regmap_write(map, TEMPSENSE1 + REG_SET, measure_freq);
	imx_set_alarm_temp(data, data->temp_passive);
	regmap_write(map, TEMPSENSE0 + REG_CLR, TEMPSENSE0_POWER_DOWN);
	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_MEASURE_TEMP);

	data->irq_enabled = true;
	data->mode = THERMAL_DEVICE_ENABLED;

	return 0;
}

static int imx_thermal_remove(struct platform_device *pdev)
{
	struct imx_thermal_data *data = platform_get_drvdata(pdev);
	struct regmap *map = data->tempmon;

	/* Disable measurements */
	regmap_write(map, TEMPSENSE0 + REG_SET, TEMPSENSE0_POWER_DOWN);

	thermal_zone_device_unregister(data->tz);
	cpufreq_cooling_unregister(data->cdev);

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int imx_thermal_suspend(struct device *dev)
{
	struct imx_thermal_data *data = dev_get_drvdata(dev);
	struct regmap *map = data->tempmon;
	u32 val;

	regmap_read(map, TEMPSENSE0, &val);
	if ((val & TEMPSENSE0_POWER_DOWN) == 0) {
		/*
		 * If a measurement is taking place, wait for a long enough
		 * time for it to finish, and then check again.  If it still
		 * does not finish, something must go wrong.
		 */
		udelay(50);
		regmap_read(map, TEMPSENSE0, &val);
		if ((val & TEMPSENSE0_POWER_DOWN) == 0)
			return -ETIMEDOUT;
	}

	return 0;
}

static int imx_thermal_resume(struct device *dev)
{
	/* Nothing to do for now */
	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(imx_thermal_pm_ops,
			 imx_thermal_suspend, imx_thermal_resume);

static const struct of_device_id of_imx_thermal_match[] = {
	{ .compatible = "fsl,imx6q-tempmon", },
	{ /* end */ }
};

static struct platform_driver imx_thermal = {
	.driver = {
		.name	= "imx_thermal",
		.owner  = THIS_MODULE,
		.pm	= &imx_thermal_pm_ops,
		.of_match_table = of_imx_thermal_match,
	},
	.probe		= imx_thermal_probe,
	.remove		= imx_thermal_remove,
};
module_platform_driver(imx_thermal);

MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("Thermal driver for Freescale i.MX SoCs");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:imx-thermal");