summaryrefslogtreecommitdiff
path: root/drivers/thermal/st/stm_thermal.c
blob: 34785b9276fc74b87c494171b4d892cbc5d4c832 (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
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
 * Author: David Hernandez Sanchez <david.hernandezsanchez@st.com> for
 * STMicroelectronics.
 */

#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/thermal.h>

#include "../thermal_hwmon.h"

/* DTS register offsets */
#define DTS_CFGR1_OFFSET	0x0
#define DTS_T0VALR1_OFFSET	0x8
#define DTS_RAMPVALR_OFFSET	0X10
#define DTS_ITR1_OFFSET		0x14
#define DTS_DR_OFFSET		0x1C
#define DTS_SR_OFFSET		0x20
#define DTS_ITENR_OFFSET	0x24
#define DTS_ICIFR_OFFSET	0x28

/* DTS_CFGR1 register mask definitions */
#define HSREF_CLK_DIV_MASK	GENMASK(30, 24)
#define TS1_SMP_TIME_MASK	GENMASK(19, 16)
#define TS1_INTRIG_SEL_MASK	GENMASK(11, 8)

/* DTS_T0VALR1 register mask definitions */
#define TS1_T0_MASK		GENMASK(17, 16)
#define TS1_FMT0_MASK		GENMASK(15, 0)

/* DTS_RAMPVALR register mask definitions */
#define TS1_RAMP_COEFF_MASK	GENMASK(15, 0)

/* DTS_ITR1 register mask definitions */
#define TS1_HITTHD_MASK		GENMASK(31, 16)
#define TS1_LITTHD_MASK		GENMASK(15, 0)

/* DTS_DR register mask definitions */
#define TS1_MFREQ_MASK		GENMASK(15, 0)

/* DTS_ITENR register mask definitions */
#define ITENR_MASK		(GENMASK(2, 0) | GENMASK(6, 4))

/* DTS_ICIFR register mask definitions */
#define ICIFR_MASK		(GENMASK(2, 0) | GENMASK(6, 4))

/* Less significant bit position definitions */
#define TS1_T0_POS		16
#define TS1_HITTHD_POS		16
#define TS1_LITTHD_POS		0
#define HSREF_CLK_DIV_POS	24

/* DTS_CFGR1 bit definitions */
#define TS1_EN			BIT(0)
#define TS1_START		BIT(4)
#define REFCLK_SEL		BIT(20)
#define REFCLK_LSE		REFCLK_SEL
#define Q_MEAS_OPT		BIT(21)
#define CALIBRATION_CONTROL	Q_MEAS_OPT

/* DTS_SR bit definitions */
#define TS_RDY			BIT(15)
/* Bit definitions below are common for DTS_SR, DTS_ITENR and DTS_CIFR */
#define HIGH_THRESHOLD		BIT(2)
#define LOW_THRESHOLD		BIT(1)

/* Constants */
#define ADJUST			100
#define ONE_MHZ			1000000
#define POLL_TIMEOUT		5000
#define STARTUP_TIME		40
#define TS1_T0_VAL0		30000  /* 30 celsius */
#define TS1_T0_VAL1		130000 /* 130 celsius */
#define NO_HW_TRIG		0
#define SAMPLING_TIME		15

struct stm_thermal_sensor {
	struct device *dev;
	struct thermal_zone_device *th_dev;
	enum thermal_device_mode mode;
	struct clk *clk;
	unsigned int low_temp_enabled;
	unsigned int high_temp_enabled;
	int irq;
	void __iomem *base;
	int t0, fmt0, ramp_coeff;
};

static int stm_enable_irq(struct stm_thermal_sensor *sensor)
{
	u32 value;

	dev_dbg(sensor->dev, "low:%d high:%d\n", sensor->low_temp_enabled,
		sensor->high_temp_enabled);

	/* Disable IT generation for low and high thresholds */
	value = readl_relaxed(sensor->base + DTS_ITENR_OFFSET);
	value &= ~(LOW_THRESHOLD | HIGH_THRESHOLD);

	if (sensor->low_temp_enabled)
		value |= HIGH_THRESHOLD;

	if (sensor->high_temp_enabled)
		value |= LOW_THRESHOLD;

	/* Enable interrupts */
	writel_relaxed(value, sensor->base + DTS_ITENR_OFFSET);

	return 0;
}

static irqreturn_t stm_thermal_irq_handler(int irq, void *sdata)
{
	struct stm_thermal_sensor *sensor = sdata;

	dev_dbg(sensor->dev, "sr:%d\n",
		readl_relaxed(sensor->base + DTS_SR_OFFSET));

	thermal_zone_device_update(sensor->th_dev, THERMAL_EVENT_UNSPECIFIED);

	stm_enable_irq(sensor);

	/* Acknoledge all DTS irqs */
	writel_relaxed(ICIFR_MASK, sensor->base + DTS_ICIFR_OFFSET);

	return IRQ_HANDLED;
}

static int stm_sensor_power_on(struct stm_thermal_sensor *sensor)
{
	int ret;
	u32 value;

	/* Enable sensor */
	value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
	value |= TS1_EN;
	writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);

	/*
	 * The DTS block can be enabled by setting TSx_EN bit in
	 * DTS_CFGRx register. It requires a startup time of
	 * 40μs. Use 5 ms as arbitrary timeout.
	 */
	ret = readl_poll_timeout(sensor->base + DTS_SR_OFFSET,
				 value, (value & TS_RDY),
				 STARTUP_TIME, POLL_TIMEOUT);
	if (ret)
		return ret;

	/* Start continuous measuring */
	value = readl_relaxed(sensor->base +
			      DTS_CFGR1_OFFSET);
	value |= TS1_START;
	writel_relaxed(value, sensor->base +
		       DTS_CFGR1_OFFSET);

	sensor->mode = THERMAL_DEVICE_ENABLED;

	return 0;
}

static int stm_sensor_power_off(struct stm_thermal_sensor *sensor)
{
	u32 value;

	sensor->mode = THERMAL_DEVICE_DISABLED;

	/* Stop measuring */
	value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
	value &= ~TS1_START;
	writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);

	/* Ensure stop is taken into account */
	usleep_range(STARTUP_TIME, POLL_TIMEOUT);

	/* Disable sensor */
	value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);
	value &= ~TS1_EN;
	writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);

	/* Ensure disable is taken into account */
	return readl_poll_timeout(sensor->base + DTS_SR_OFFSET, value,
				  !(value & TS_RDY),
				  STARTUP_TIME, POLL_TIMEOUT);
}

static int stm_thermal_calibration(struct stm_thermal_sensor *sensor)
{
	u32 value, clk_freq;
	u32 prescaler;

	/* Figure out prescaler value for PCLK during calibration */
	clk_freq = clk_get_rate(sensor->clk);
	if (!clk_freq)
		return -EINVAL;

	prescaler = 0;
	clk_freq /= ONE_MHZ;
	if (clk_freq) {
		while (prescaler <= clk_freq)
			prescaler++;
	}

	value = readl_relaxed(sensor->base + DTS_CFGR1_OFFSET);

	/* Clear prescaler */
	value &= ~HSREF_CLK_DIV_MASK;

	/* Set prescaler. pclk_freq/prescaler < 1MHz */
	value |= (prescaler << HSREF_CLK_DIV_POS);

	/* Select PCLK as reference clock */
	value &= ~REFCLK_SEL;

	/* Set maximal sampling time for better precision */
	value |= TS1_SMP_TIME_MASK;

	/* Measure with calibration */
	value &= ~CALIBRATION_CONTROL;

	/* select trigger */
	value &= ~TS1_INTRIG_SEL_MASK;
	value |= NO_HW_TRIG;

	writel_relaxed(value, sensor->base + DTS_CFGR1_OFFSET);

	return 0;
}

/* Fill in DTS structure with factory sensor values */
static int stm_thermal_read_factory_settings(struct stm_thermal_sensor *sensor)
{
	/* Retrieve engineering calibration temperature */
	sensor->t0 = readl_relaxed(sensor->base + DTS_T0VALR1_OFFSET) &
					TS1_T0_MASK;
	if (!sensor->t0)
		sensor->t0 = TS1_T0_VAL0;
	else
		sensor->t0 = TS1_T0_VAL1;

	/* Retrieve fmt0 and put it on Hz */
	sensor->fmt0 = ADJUST * (readl_relaxed(sensor->base +
				 DTS_T0VALR1_OFFSET) & TS1_FMT0_MASK);

	/* Retrieve ramp coefficient */
	sensor->ramp_coeff = readl_relaxed(sensor->base + DTS_RAMPVALR_OFFSET) &
					   TS1_RAMP_COEFF_MASK;

	if (!sensor->fmt0 || !sensor->ramp_coeff) {
		dev_err(sensor->dev, "%s: wrong setting\n", __func__);
		return -EINVAL;
	}

	dev_dbg(sensor->dev, "%s: T0 = %doC, FMT0 = %dHz, RAMP_COEFF = %dHz/oC",
		__func__, sensor->t0, sensor->fmt0, sensor->ramp_coeff);

	return 0;
}

static int stm_thermal_calculate_threshold(struct stm_thermal_sensor *sensor,
					   int temp, u32 *th)
{
	int freqM;

	/* Figure out the CLK_PTAT frequency for a given temperature */
	freqM = ((temp - sensor->t0) * sensor->ramp_coeff) / 1000 +
		sensor->fmt0;

	/* Figure out the threshold sample number */
	*th = clk_get_rate(sensor->clk) * SAMPLING_TIME / freqM;
	if (!*th)
		return -EINVAL;

	dev_dbg(sensor->dev, "freqM=%d Hz, threshold=0x%x", freqM, *th);

	return 0;
}

/* Disable temperature interrupt */
static int stm_disable_irq(struct stm_thermal_sensor *sensor)
{
	u32 value;

	/* Disable IT generation */
	value = readl_relaxed(sensor->base + DTS_ITENR_OFFSET);
	value &= ~ITENR_MASK;
	writel_relaxed(value, sensor->base + DTS_ITENR_OFFSET);

	return 0;
}

static int stm_thermal_set_trips(struct thermal_zone_device *tz, int low, int high)
{
	struct stm_thermal_sensor *sensor = thermal_zone_device_priv(tz);
	u32 itr1, th;
	int ret;

	dev_dbg(sensor->dev, "set trips %d <--> %d\n", low, high);

	/* Erase threshold content */
	itr1 = readl_relaxed(sensor->base + DTS_ITR1_OFFSET);
	itr1 &= ~(TS1_LITTHD_MASK | TS1_HITTHD_MASK);

	/*
	 * Disable low-temp if "low" is too small. As per thermal framework
	 * API, we use -INT_MAX rather than INT_MIN.
	 */

	if (low > -INT_MAX) {
		sensor->low_temp_enabled = 1;
		/* add 0.5 of hysteresis due to measurement error */
		ret = stm_thermal_calculate_threshold(sensor, low - 500, &th);
		if (ret)
			return ret;

		itr1 |= (TS1_HITTHD_MASK  & (th << TS1_HITTHD_POS));
	} else {
		sensor->low_temp_enabled = 0;
	}

	/* Disable high-temp if "high" is too big. */
	if (high < INT_MAX) {
		sensor->high_temp_enabled = 1;
		ret = stm_thermal_calculate_threshold(sensor, high, &th);
		if (ret)
			return ret;

		itr1 |= (TS1_LITTHD_MASK  & (th << TS1_LITTHD_POS));
	} else {
		sensor->high_temp_enabled = 0;
	}

	/* Write new threshod values*/
	writel_relaxed(itr1, sensor->base + DTS_ITR1_OFFSET);

	return 0;
}

/* Callback to get temperature from HW */
static int stm_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
{
	struct stm_thermal_sensor *sensor = thermal_zone_device_priv(tz);
	u32 periods;
	int freqM, ret;

	if (sensor->mode != THERMAL_DEVICE_ENABLED)
		return -EAGAIN;

	/* Retrieve the number of periods sampled */
	ret = readl_relaxed_poll_timeout(sensor->base + DTS_DR_OFFSET, periods,
					 (periods & TS1_MFREQ_MASK),
					 STARTUP_TIME, POLL_TIMEOUT);
	if (ret)
		return ret;

	/* Figure out the CLK_PTAT frequency */
	freqM = (clk_get_rate(sensor->clk) * SAMPLING_TIME) / periods;
	if (!freqM)
		return -EINVAL;

	/* Figure out the temperature in mili celsius */
	*temp = (freqM - sensor->fmt0) * 1000 / sensor->ramp_coeff + sensor->t0;

	return 0;
}

/* Registers DTS irq to be visible by GIC */
static int stm_register_irq(struct stm_thermal_sensor *sensor)
{
	struct device *dev = sensor->dev;
	struct platform_device *pdev = to_platform_device(dev);
	int ret;

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

	ret = devm_request_threaded_irq(dev, sensor->irq,
					NULL,
					stm_thermal_irq_handler,
					IRQF_ONESHOT,
					dev->driver->name, sensor);
	if (ret) {
		dev_err(dev, "%s: Failed to register IRQ %d\n", __func__,
			sensor->irq);
		return ret;
	}

	dev_dbg(dev, "%s: thermal IRQ registered", __func__);

	return 0;
}

static int stm_thermal_sensor_off(struct stm_thermal_sensor *sensor)
{
	int ret;

	stm_disable_irq(sensor);

	ret = stm_sensor_power_off(sensor);
	if (ret)
		return ret;

	clk_disable_unprepare(sensor->clk);

	return 0;
}

static int stm_thermal_prepare(struct stm_thermal_sensor *sensor)
{
	int ret;

	ret = clk_prepare_enable(sensor->clk);
	if (ret)
		return ret;

	ret = stm_thermal_read_factory_settings(sensor);
	if (ret)
		goto thermal_unprepare;

	ret = stm_thermal_calibration(sensor);
	if (ret)
		goto thermal_unprepare;

	return 0;

thermal_unprepare:
	clk_disable_unprepare(sensor->clk);

	return ret;
}

#ifdef CONFIG_PM_SLEEP
static int stm_thermal_suspend(struct device *dev)
{
	struct stm_thermal_sensor *sensor = dev_get_drvdata(dev);

	return stm_thermal_sensor_off(sensor);
}

static int stm_thermal_resume(struct device *dev)
{
	int ret;
	struct stm_thermal_sensor *sensor = dev_get_drvdata(dev);

	ret = stm_thermal_prepare(sensor);
	if (ret)
		return ret;

	ret = stm_sensor_power_on(sensor);
	if (ret)
		return ret;

	thermal_zone_device_update(sensor->th_dev, THERMAL_EVENT_UNSPECIFIED);
	stm_enable_irq(sensor);

	return 0;
}
#endif /* CONFIG_PM_SLEEP */

static SIMPLE_DEV_PM_OPS(stm_thermal_pm_ops,
			 stm_thermal_suspend, stm_thermal_resume);

static const struct thermal_zone_device_ops stm_tz_ops = {
	.get_temp	= stm_thermal_get_temp,
	.set_trips	= stm_thermal_set_trips,
};

static const struct of_device_id stm_thermal_of_match[] = {
		{ .compatible = "st,stm32-thermal"},
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, stm_thermal_of_match);

static int stm_thermal_probe(struct platform_device *pdev)
{
	struct stm_thermal_sensor *sensor;
	void __iomem *base;
	int ret;

	if (!pdev->dev.of_node) {
		dev_err(&pdev->dev, "%s: device tree node not found\n",
			__func__);
		return -EINVAL;
	}

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

	platform_set_drvdata(pdev, sensor);

	sensor->dev = &pdev->dev;

	base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
	if (IS_ERR(base))
		return PTR_ERR(base);

	/* Populate sensor */
	sensor->base = base;

	sensor->clk = devm_clk_get(&pdev->dev, "pclk");
	if (IS_ERR(sensor->clk)) {
		dev_err(&pdev->dev, "%s: failed to fetch PCLK clock\n",
			__func__);
		return PTR_ERR(sensor->clk);
	}

	stm_disable_irq(sensor);

	/* Clear irq flags */
	writel_relaxed(ICIFR_MASK, sensor->base + DTS_ICIFR_OFFSET);

	/* Configure and enable HW sensor */
	ret = stm_thermal_prepare(sensor);
	if (ret) {
		dev_err(&pdev->dev, "Error prepare sensor: %d\n", ret);
		return ret;
	}

	ret = stm_sensor_power_on(sensor);
	if (ret) {
		dev_err(&pdev->dev, "Error power on sensor: %d\n", ret);
		return ret;
	}

	sensor->th_dev = devm_thermal_of_zone_register(&pdev->dev, 0,
						       sensor,
						       &stm_tz_ops);

	if (IS_ERR(sensor->th_dev)) {
		dev_err(&pdev->dev, "%s: thermal zone sensor registering KO\n",
			__func__);
		ret = PTR_ERR(sensor->th_dev);
		return ret;
	}

	/* Register IRQ into GIC */
	ret = stm_register_irq(sensor);
	if (ret)
		goto err_tz;

	stm_enable_irq(sensor);

	/*
	 * Thermal_zone doesn't enable hwmon as default,
	 * enable it here
	 */
	ret = thermal_add_hwmon_sysfs(sensor->th_dev);
	if (ret)
		goto err_tz;

	dev_info(&pdev->dev, "%s: Driver initialized successfully\n",
		 __func__);

	return 0;

err_tz:
	return ret;
}

static void stm_thermal_remove(struct platform_device *pdev)
{
	struct stm_thermal_sensor *sensor = platform_get_drvdata(pdev);

	stm_thermal_sensor_off(sensor);
	thermal_remove_hwmon_sysfs(sensor->th_dev);
}

static struct platform_driver stm_thermal_driver = {
	.driver = {
		.name	= "stm_thermal",
		.pm     = &stm_thermal_pm_ops,
		.of_match_table = stm_thermal_of_match,
	},
	.probe		= stm_thermal_probe,
	.remove_new	= stm_thermal_remove,
};
module_platform_driver(stm_thermal_driver);

MODULE_DESCRIPTION("STMicroelectronics STM32 Thermal Sensor Driver");
MODULE_AUTHOR("David Hernandez Sanchez <david.hernandezsanchez@st.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:stm_thermal");