xref: /linux/drivers/hwmon/axi-fan-control.c (revision a4eb44a6435d6d8f9e642407a4a06f65eb90ca04) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Fan Control HDL CORE driver
4  *
5  * Copyright 2019 Analog Devices Inc.
6  */
7 #include <linux/bits.h>
8 #include <linux/clk.h>
9 #include <linux/fpga/adi-axi-common.h>
10 #include <linux/hwmon.h>
11 #include <linux/hwmon-sysfs.h>
12 #include <linux/interrupt.h>
13 #include <linux/io.h>
14 #include <linux/kernel.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/platform_device.h>
18 
19 /* register map */
20 #define ADI_REG_RSTN		0x0080
21 #define ADI_REG_PWM_WIDTH	0x0084
22 #define ADI_REG_TACH_PERIOD	0x0088
23 #define ADI_REG_TACH_TOLERANCE	0x008c
24 #define ADI_REG_PWM_PERIOD	0x00c0
25 #define ADI_REG_TACH_MEASUR	0x00c4
26 #define ADI_REG_TEMPERATURE	0x00c8
27 #define ADI_REG_TEMP_00_H	0x0100
28 #define ADI_REG_TEMP_25_L	0x0104
29 #define ADI_REG_TEMP_25_H	0x0108
30 #define ADI_REG_TEMP_50_L	0x010c
31 #define ADI_REG_TEMP_50_H	0x0110
32 #define ADI_REG_TEMP_75_L	0x0114
33 #define ADI_REG_TEMP_75_H	0x0118
34 #define ADI_REG_TEMP_100_L	0x011c
35 
36 #define ADI_REG_IRQ_MASK	0x0040
37 #define ADI_REG_IRQ_PENDING	0x0044
38 #define ADI_REG_IRQ_SRC		0x0048
39 
40 /* IRQ sources */
41 #define ADI_IRQ_SRC_PWM_CHANGED		BIT(0)
42 #define ADI_IRQ_SRC_TACH_ERR		BIT(1)
43 #define ADI_IRQ_SRC_TEMP_INCREASE	BIT(2)
44 #define ADI_IRQ_SRC_NEW_MEASUR		BIT(3)
45 #define ADI_IRQ_SRC_MASK		GENMASK(3, 0)
46 #define ADI_IRQ_MASK_OUT_ALL		0xFFFFFFFFU
47 
48 #define SYSFS_PWM_MAX			255
49 
50 struct axi_fan_control_data {
51 	void __iomem *base;
52 	struct device *hdev;
53 	unsigned long clk_rate;
54 	int irq;
55 	/* pulses per revolution */
56 	u32 ppr;
57 	bool hw_pwm_req;
58 	bool update_tacho_params;
59 	u8 fan_fault;
60 };
61 
62 static inline void axi_iowrite(const u32 val, const u32 reg,
63 			       const struct axi_fan_control_data *ctl)
64 {
65 	iowrite32(val, ctl->base + reg);
66 }
67 
68 static inline u32 axi_ioread(const u32 reg,
69 			     const struct axi_fan_control_data *ctl)
70 {
71 	return ioread32(ctl->base + reg);
72 }
73 
74 /*
75  * The core calculates the temperature as:
76  *	T = /raw * 509.3140064 / 65535) - 280.2308787
77  */
78 static ssize_t axi_fan_control_show(struct device *dev, struct device_attribute *da, char *buf)
79 {
80 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
81 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
82 	u32 temp = axi_ioread(attr->index, ctl);
83 
84 	temp = DIV_ROUND_CLOSEST_ULL(temp * 509314ULL, 65535) - 280230;
85 
86 	return sprintf(buf, "%u\n", temp);
87 }
88 
89 static ssize_t axi_fan_control_store(struct device *dev, struct device_attribute *da,
90 				     const char *buf, size_t count)
91 {
92 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
93 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
94 	u32 temp;
95 	int ret;
96 
97 	ret = kstrtou32(buf, 10, &temp);
98 	if (ret)
99 		return ret;
100 
101 	temp = DIV_ROUND_CLOSEST_ULL((temp + 280230) * 65535ULL, 509314);
102 	axi_iowrite(temp, attr->index, ctl);
103 
104 	return count;
105 }
106 
107 static long axi_fan_control_get_pwm_duty(const struct axi_fan_control_data *ctl)
108 {
109 	u32 pwm_width = axi_ioread(ADI_REG_PWM_WIDTH, ctl);
110 	u32 pwm_period = axi_ioread(ADI_REG_PWM_PERIOD, ctl);
111 	/*
112 	 * PWM_PERIOD is a RO register set by the core. It should never be 0.
113 	 * For now we are trusting the HW...
114 	 */
115 	return DIV_ROUND_CLOSEST(pwm_width * SYSFS_PWM_MAX, pwm_period);
116 }
117 
118 static int axi_fan_control_set_pwm_duty(const long val,
119 					struct axi_fan_control_data *ctl)
120 {
121 	u32 pwm_period = axi_ioread(ADI_REG_PWM_PERIOD, ctl);
122 	u32 new_width;
123 	long __val = clamp_val(val, 0, SYSFS_PWM_MAX);
124 
125 	new_width = DIV_ROUND_CLOSEST(__val * pwm_period, SYSFS_PWM_MAX);
126 
127 	axi_iowrite(new_width, ADI_REG_PWM_WIDTH, ctl);
128 
129 	return 0;
130 }
131 
132 static long axi_fan_control_get_fan_rpm(const struct axi_fan_control_data *ctl)
133 {
134 	const u32 tach = axi_ioread(ADI_REG_TACH_MEASUR, ctl);
135 
136 	if (tach == 0)
137 		/* should we return error, EAGAIN maybe? */
138 		return 0;
139 	/*
140 	 * The tacho period should be:
141 	 *      TACH = 60/(ppr * rpm), where rpm is revolutions per second
142 	 *      and ppr is pulses per revolution.
143 	 * Given the tacho period, we can multiply it by the input clock
144 	 * so that we know how many clocks we need to have this period.
145 	 * From this, we can derive the RPM value.
146 	 */
147 	return DIV_ROUND_CLOSEST(60 * ctl->clk_rate, ctl->ppr * tach);
148 }
149 
150 static int axi_fan_control_read_temp(struct device *dev, u32 attr, long *val)
151 {
152 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
153 	long raw_temp;
154 
155 	switch (attr) {
156 	case hwmon_temp_input:
157 		raw_temp = axi_ioread(ADI_REG_TEMPERATURE, ctl);
158 		/*
159 		 * The formula for the temperature is:
160 		 *      T = (ADC * 501.3743 / 2^bits) - 273.6777
161 		 * It's multiplied by 1000 to have millidegrees as
162 		 * specified by the hwmon sysfs interface.
163 		 */
164 		*val = ((raw_temp * 501374) >> 16) - 273677;
165 		return 0;
166 	default:
167 		return -ENOTSUPP;
168 	}
169 }
170 
171 static int axi_fan_control_read_fan(struct device *dev, u32 attr, long *val)
172 {
173 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
174 
175 	switch (attr) {
176 	case hwmon_fan_fault:
177 		*val = ctl->fan_fault;
178 		/* clear it now */
179 		ctl->fan_fault = 0;
180 		return 0;
181 	case hwmon_fan_input:
182 		*val = axi_fan_control_get_fan_rpm(ctl);
183 		return 0;
184 	default:
185 		return -ENOTSUPP;
186 	}
187 }
188 
189 static int axi_fan_control_read_pwm(struct device *dev, u32 attr, long *val)
190 {
191 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
192 
193 	switch (attr) {
194 	case hwmon_pwm_input:
195 		*val = axi_fan_control_get_pwm_duty(ctl);
196 		return 0;
197 	default:
198 		return -ENOTSUPP;
199 	}
200 }
201 
202 static int axi_fan_control_write_pwm(struct device *dev, u32 attr, long val)
203 {
204 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
205 
206 	switch (attr) {
207 	case hwmon_pwm_input:
208 		return axi_fan_control_set_pwm_duty(val, ctl);
209 	default:
210 		return -ENOTSUPP;
211 	}
212 }
213 
214 static int axi_fan_control_read_labels(struct device *dev,
215 				       enum hwmon_sensor_types type,
216 				       u32 attr, int channel, const char **str)
217 {
218 	switch (type) {
219 	case hwmon_fan:
220 		*str = "FAN";
221 		return 0;
222 	case hwmon_temp:
223 		*str = "SYSMON4";
224 		return 0;
225 	default:
226 		return -ENOTSUPP;
227 	}
228 }
229 
230 static int axi_fan_control_read(struct device *dev,
231 				enum hwmon_sensor_types type,
232 				u32 attr, int channel, long *val)
233 {
234 	switch (type) {
235 	case hwmon_fan:
236 		return axi_fan_control_read_fan(dev, attr, val);
237 	case hwmon_pwm:
238 		return axi_fan_control_read_pwm(dev, attr, val);
239 	case hwmon_temp:
240 		return axi_fan_control_read_temp(dev, attr, val);
241 	default:
242 		return -ENOTSUPP;
243 	}
244 }
245 
246 static int axi_fan_control_write(struct device *dev,
247 				 enum hwmon_sensor_types type,
248 				 u32 attr, int channel, long val)
249 {
250 	switch (type) {
251 	case hwmon_pwm:
252 		return axi_fan_control_write_pwm(dev, attr, val);
253 	default:
254 		return -ENOTSUPP;
255 	}
256 }
257 
258 static umode_t axi_fan_control_fan_is_visible(const u32 attr)
259 {
260 	switch (attr) {
261 	case hwmon_fan_input:
262 	case hwmon_fan_fault:
263 	case hwmon_fan_label:
264 		return 0444;
265 	default:
266 		return 0;
267 	}
268 }
269 
270 static umode_t axi_fan_control_pwm_is_visible(const u32 attr)
271 {
272 	switch (attr) {
273 	case hwmon_pwm_input:
274 		return 0644;
275 	default:
276 		return 0;
277 	}
278 }
279 
280 static umode_t axi_fan_control_temp_is_visible(const u32 attr)
281 {
282 	switch (attr) {
283 	case hwmon_temp_input:
284 	case hwmon_temp_label:
285 		return 0444;
286 	default:
287 		return 0;
288 	}
289 }
290 
291 static umode_t axi_fan_control_is_visible(const void *data,
292 					  enum hwmon_sensor_types type,
293 					  u32 attr, int channel)
294 {
295 	switch (type) {
296 	case hwmon_fan:
297 		return axi_fan_control_fan_is_visible(attr);
298 	case hwmon_pwm:
299 		return axi_fan_control_pwm_is_visible(attr);
300 	case hwmon_temp:
301 		return axi_fan_control_temp_is_visible(attr);
302 	default:
303 		return 0;
304 	}
305 }
306 
307 /*
308  * This core has two main ways of changing the PWM duty cycle. It is done,
309  * either by a request from userspace (writing on pwm1_input) or by the
310  * core itself. When the change is done by the core, it will use predefined
311  * parameters to evaluate the tach signal and, on that case we cannot set them.
312  * On the other hand, when the request is done by the user, with some arbitrary
313  * value that the core does not now about, we have to provide the tach
314  * parameters so that, the core can evaluate the signal. On the IRQ handler we
315  * distinguish this by using the ADI_IRQ_SRC_TEMP_INCREASE interrupt. This tell
316  * us that the CORE requested a new duty cycle. After this, there is 5s delay
317  * on which the core waits for the fan rotation speed to stabilize. After this
318  * we get ADI_IRQ_SRC_PWM_CHANGED irq where we will decide if we need to set
319  * the tach parameters or not on the next tach measurement cycle (corresponding
320  * already to the ney duty cycle) based on the %ctl->hw_pwm_req flag.
321  */
322 static irqreturn_t axi_fan_control_irq_handler(int irq, void *data)
323 {
324 	struct axi_fan_control_data *ctl = (struct axi_fan_control_data *)data;
325 	u32 irq_pending = axi_ioread(ADI_REG_IRQ_PENDING, ctl);
326 	u32 clear_mask;
327 
328 	if (irq_pending & ADI_IRQ_SRC_TEMP_INCREASE)
329 		/* hardware requested a new pwm */
330 		ctl->hw_pwm_req = true;
331 
332 	if (irq_pending & ADI_IRQ_SRC_PWM_CHANGED) {
333 		/*
334 		 * if the pwm changes on behalf of software,
335 		 * we need to provide new tacho parameters to the core.
336 		 * Wait for the next measurement for that...
337 		 */
338 		if (!ctl->hw_pwm_req) {
339 			ctl->update_tacho_params = true;
340 		} else {
341 			ctl->hw_pwm_req = false;
342 			sysfs_notify(&ctl->hdev->kobj, NULL, "pwm1");
343 		}
344 	}
345 
346 	if (irq_pending & ADI_IRQ_SRC_NEW_MEASUR) {
347 		if (ctl->update_tacho_params) {
348 			u32 new_tach = axi_ioread(ADI_REG_TACH_MEASUR, ctl);
349 			/* get 25% tolerance */
350 			u32 tach_tol = DIV_ROUND_CLOSEST(new_tach * 25, 100);
351 
352 			/* set new tacho parameters */
353 			axi_iowrite(new_tach, ADI_REG_TACH_PERIOD, ctl);
354 			axi_iowrite(tach_tol, ADI_REG_TACH_TOLERANCE, ctl);
355 			ctl->update_tacho_params = false;
356 		}
357 	}
358 
359 	if (irq_pending & ADI_IRQ_SRC_TACH_ERR)
360 		ctl->fan_fault = 1;
361 
362 	/* clear all interrupts */
363 	clear_mask = irq_pending & ADI_IRQ_SRC_MASK;
364 	axi_iowrite(clear_mask, ADI_REG_IRQ_PENDING, ctl);
365 
366 	return IRQ_HANDLED;
367 }
368 
369 static int axi_fan_control_init(struct axi_fan_control_data *ctl,
370 				const struct device_node *np)
371 {
372 	int ret;
373 
374 	/* get fan pulses per revolution */
375 	ret = of_property_read_u32(np, "pulses-per-revolution", &ctl->ppr);
376 	if (ret)
377 		return ret;
378 
379 	/* 1, 2 and 4 are the typical and accepted values */
380 	if (ctl->ppr != 1 && ctl->ppr != 2 && ctl->ppr != 4)
381 		return -EINVAL;
382 	/*
383 	 * Enable all IRQs
384 	 */
385 	axi_iowrite(ADI_IRQ_MASK_OUT_ALL &
386 		    ~(ADI_IRQ_SRC_NEW_MEASUR | ADI_IRQ_SRC_TACH_ERR |
387 		      ADI_IRQ_SRC_PWM_CHANGED | ADI_IRQ_SRC_TEMP_INCREASE),
388 		    ADI_REG_IRQ_MASK, ctl);
389 
390 	/* bring the device out of reset */
391 	axi_iowrite(0x01, ADI_REG_RSTN, ctl);
392 
393 	return ret;
394 }
395 
396 static void axi_fan_control_clk_disable(void *clk)
397 {
398 	clk_disable_unprepare(clk);
399 }
400 
401 static const struct hwmon_channel_info *axi_fan_control_info[] = {
402 	HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT),
403 	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_FAULT | HWMON_F_LABEL),
404 	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_LABEL),
405 	NULL
406 };
407 
408 static const struct hwmon_ops axi_fan_control_hwmon_ops = {
409 	.is_visible = axi_fan_control_is_visible,
410 	.read = axi_fan_control_read,
411 	.write = axi_fan_control_write,
412 	.read_string = axi_fan_control_read_labels,
413 };
414 
415 static const struct hwmon_chip_info axi_chip_info = {
416 	.ops = &axi_fan_control_hwmon_ops,
417 	.info = axi_fan_control_info,
418 };
419 
420 /* temperature threshold below which PWM should be 0% */
421 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point1_temp_hyst, axi_fan_control, ADI_REG_TEMP_00_H);
422 /* temperature threshold above which PWM should be 25% */
423 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point1_temp, axi_fan_control, ADI_REG_TEMP_25_L);
424 /* temperature threshold below which PWM should be 25% */
425 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point2_temp_hyst, axi_fan_control, ADI_REG_TEMP_25_H);
426 /* temperature threshold above which PWM should be 50% */
427 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point2_temp, axi_fan_control, ADI_REG_TEMP_50_L);
428 /* temperature threshold below which PWM should be 50% */
429 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point3_temp_hyst, axi_fan_control, ADI_REG_TEMP_50_H);
430 /* temperature threshold above which PWM should be 75% */
431 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point3_temp, axi_fan_control, ADI_REG_TEMP_75_L);
432 /* temperature threshold below which PWM should be 75% */
433 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point4_temp_hyst, axi_fan_control, ADI_REG_TEMP_75_H);
434 /* temperature threshold above which PWM should be 100% */
435 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point4_temp, axi_fan_control, ADI_REG_TEMP_100_L);
436 
437 static struct attribute *axi_fan_control_attrs[] = {
438 	&sensor_dev_attr_pwm1_auto_point1_temp_hyst.dev_attr.attr,
439 	&sensor_dev_attr_pwm1_auto_point1_temp.dev_attr.attr,
440 	&sensor_dev_attr_pwm1_auto_point2_temp_hyst.dev_attr.attr,
441 	&sensor_dev_attr_pwm1_auto_point2_temp.dev_attr.attr,
442 	&sensor_dev_attr_pwm1_auto_point3_temp_hyst.dev_attr.attr,
443 	&sensor_dev_attr_pwm1_auto_point3_temp.dev_attr.attr,
444 	&sensor_dev_attr_pwm1_auto_point4_temp_hyst.dev_attr.attr,
445 	&sensor_dev_attr_pwm1_auto_point4_temp.dev_attr.attr,
446 	NULL,
447 };
448 ATTRIBUTE_GROUPS(axi_fan_control);
449 
450 static const u32 version_1_0_0 = ADI_AXI_PCORE_VER(1, 0, 'a');
451 
452 static const struct of_device_id axi_fan_control_of_match[] = {
453 	{ .compatible = "adi,axi-fan-control-1.00.a",
454 		.data = (void *)&version_1_0_0},
455 	{},
456 };
457 MODULE_DEVICE_TABLE(of, axi_fan_control_of_match);
458 
459 static int axi_fan_control_probe(struct platform_device *pdev)
460 {
461 	struct axi_fan_control_data *ctl;
462 	struct clk *clk;
463 	const struct of_device_id *id;
464 	const char *name = "axi_fan_control";
465 	u32 version;
466 	int ret;
467 
468 	id = of_match_node(axi_fan_control_of_match, pdev->dev.of_node);
469 	if (!id)
470 		return -EINVAL;
471 
472 	ctl = devm_kzalloc(&pdev->dev, sizeof(*ctl), GFP_KERNEL);
473 	if (!ctl)
474 		return -ENOMEM;
475 
476 	ctl->base = devm_platform_ioremap_resource(pdev, 0);
477 	if (IS_ERR(ctl->base))
478 		return PTR_ERR(ctl->base);
479 
480 	clk = devm_clk_get(&pdev->dev, NULL);
481 	if (IS_ERR(clk)) {
482 		dev_err(&pdev->dev, "clk_get failed with %ld\n", PTR_ERR(clk));
483 		return PTR_ERR(clk);
484 	}
485 
486 	ret = clk_prepare_enable(clk);
487 	if (ret)
488 		return ret;
489 
490 	ret = devm_add_action_or_reset(&pdev->dev, axi_fan_control_clk_disable, clk);
491 	if (ret)
492 		return ret;
493 
494 	ctl->clk_rate = clk_get_rate(clk);
495 	if (!ctl->clk_rate)
496 		return -EINVAL;
497 
498 	version = axi_ioread(ADI_AXI_REG_VERSION, ctl);
499 	if (ADI_AXI_PCORE_VER_MAJOR(version) !=
500 	    ADI_AXI_PCORE_VER_MAJOR((*(u32 *)id->data))) {
501 		dev_err(&pdev->dev, "Major version mismatch. Expected %d.%.2d.%c, Reported %d.%.2d.%c\n",
502 			ADI_AXI_PCORE_VER_MAJOR((*(u32 *)id->data)),
503 			ADI_AXI_PCORE_VER_MINOR((*(u32 *)id->data)),
504 			ADI_AXI_PCORE_VER_PATCH((*(u32 *)id->data)),
505 			ADI_AXI_PCORE_VER_MAJOR(version),
506 			ADI_AXI_PCORE_VER_MINOR(version),
507 			ADI_AXI_PCORE_VER_PATCH(version));
508 		return -ENODEV;
509 	}
510 
511 	ctl->irq = platform_get_irq(pdev, 0);
512 	if (ctl->irq < 0)
513 		return ctl->irq;
514 
515 	ret = devm_request_threaded_irq(&pdev->dev, ctl->irq, NULL,
516 					axi_fan_control_irq_handler,
517 					IRQF_ONESHOT | IRQF_TRIGGER_HIGH,
518 					pdev->driver_override, ctl);
519 	if (ret) {
520 		dev_err(&pdev->dev, "failed to request an irq, %d", ret);
521 		return ret;
522 	}
523 
524 	ret = axi_fan_control_init(ctl, pdev->dev.of_node);
525 	if (ret) {
526 		dev_err(&pdev->dev, "Failed to initialize device\n");
527 		return ret;
528 	}
529 
530 	ctl->hdev = devm_hwmon_device_register_with_info(&pdev->dev,
531 							 name,
532 							 ctl,
533 							 &axi_chip_info,
534 							 axi_fan_control_groups);
535 
536 	return PTR_ERR_OR_ZERO(ctl->hdev);
537 }
538 
539 static struct platform_driver axi_fan_control_driver = {
540 	.driver = {
541 		.name = "axi_fan_control_driver",
542 		.of_match_table = axi_fan_control_of_match,
543 	},
544 	.probe = axi_fan_control_probe,
545 };
546 module_platform_driver(axi_fan_control_driver);
547 
548 MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
549 MODULE_DESCRIPTION("Analog Devices Fan Control HDL CORE driver");
550 MODULE_LICENSE("GPL");
551