xref: /linux/drivers/hwmon/axi-fan-control.c (revision f5c31bcf604db54470868f3118a60dc4a9ba8813) 
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/mod_devicetable.h>
17 #include <linux/platform_device.h>
18 #include <linux/property.h>
19 
20 /* register map */
21 #define ADI_REG_RSTN		0x0080
22 #define ADI_REG_PWM_WIDTH	0x0084
23 #define ADI_REG_TACH_PERIOD	0x0088
24 #define ADI_REG_TACH_TOLERANCE	0x008c
25 #define ADI_REG_PWM_PERIOD	0x00c0
26 #define ADI_REG_TACH_MEASUR	0x00c4
27 #define ADI_REG_TEMPERATURE	0x00c8
28 #define ADI_REG_TEMP_00_H	0x0100
29 #define ADI_REG_TEMP_25_L	0x0104
30 #define ADI_REG_TEMP_25_H	0x0108
31 #define ADI_REG_TEMP_50_L	0x010c
32 #define ADI_REG_TEMP_50_H	0x0110
33 #define ADI_REG_TEMP_75_L	0x0114
34 #define ADI_REG_TEMP_75_H	0x0118
35 #define ADI_REG_TEMP_100_L	0x011c
36 
37 #define ADI_REG_IRQ_MASK	0x0040
38 #define ADI_REG_IRQ_PENDING	0x0044
39 #define ADI_REG_IRQ_SRC		0x0048
40 
41 /* IRQ sources */
42 #define ADI_IRQ_SRC_PWM_CHANGED		BIT(0)
43 #define ADI_IRQ_SRC_TACH_ERR		BIT(1)
44 #define ADI_IRQ_SRC_TEMP_INCREASE	BIT(2)
45 #define ADI_IRQ_SRC_NEW_MEASUR		BIT(3)
46 #define ADI_IRQ_SRC_MASK		GENMASK(3, 0)
47 #define ADI_IRQ_MASK_OUT_ALL		0xFFFFFFFFU
48 
49 #define SYSFS_PWM_MAX			255
50 
51 struct axi_fan_control_data {
52 	void __iomem *base;
53 	struct device *hdev;
54 	unsigned long clk_rate;
55 	int irq;
56 	/* pulses per revolution */
57 	u32 ppr;
58 	bool hw_pwm_req;
59 	bool update_tacho_params;
60 	u8 fan_fault;
61 };
62 
63 static inline void axi_iowrite(const u32 val, const u32 reg,
64 			       const struct axi_fan_control_data *ctl)
65 {
66 	iowrite32(val, ctl->base + reg);
67 }
68 
69 static inline u32 axi_ioread(const u32 reg,
70 			     const struct axi_fan_control_data *ctl)
71 {
72 	return ioread32(ctl->base + reg);
73 }
74 
75 /*
76  * The core calculates the temperature as:
77  *	T = /raw * 509.3140064 / 65535) - 280.2308787
78  */
79 static ssize_t axi_fan_control_show(struct device *dev, struct device_attribute *da, char *buf)
80 {
81 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
82 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
83 	u32 temp = axi_ioread(attr->index, ctl);
84 
85 	temp = DIV_ROUND_CLOSEST_ULL(temp * 509314ULL, 65535) - 280230;
86 
87 	return sysfs_emit(buf, "%u\n", temp);
88 }
89 
90 static ssize_t axi_fan_control_store(struct device *dev, struct device_attribute *da,
91 				     const char *buf, size_t count)
92 {
93 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
94 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
95 	u32 temp;
96 	int ret;
97 
98 	ret = kstrtou32(buf, 10, &temp);
99 	if (ret)
100 		return ret;
101 
102 	temp = DIV_ROUND_CLOSEST_ULL((temp + 280230) * 65535ULL, 509314);
103 	axi_iowrite(temp, attr->index, ctl);
104 
105 	return count;
106 }
107 
108 static long axi_fan_control_get_pwm_duty(const struct axi_fan_control_data *ctl)
109 {
110 	u32 pwm_width = axi_ioread(ADI_REG_PWM_WIDTH, ctl);
111 	u32 pwm_period = axi_ioread(ADI_REG_PWM_PERIOD, ctl);
112 	/*
113 	 * PWM_PERIOD is a RO register set by the core. It should never be 0.
114 	 * For now we are trusting the HW...
115 	 */
116 	return DIV_ROUND_CLOSEST(pwm_width * SYSFS_PWM_MAX, pwm_period);
117 }
118 
119 static int axi_fan_control_set_pwm_duty(const long val,
120 					struct axi_fan_control_data *ctl)
121 {
122 	u32 pwm_period = axi_ioread(ADI_REG_PWM_PERIOD, ctl);
123 	u32 new_width;
124 	long __val = clamp_val(val, 0, SYSFS_PWM_MAX);
125 
126 	new_width = DIV_ROUND_CLOSEST(__val * pwm_period, SYSFS_PWM_MAX);
127 
128 	axi_iowrite(new_width, ADI_REG_PWM_WIDTH, ctl);
129 
130 	return 0;
131 }
132 
133 static long axi_fan_control_get_fan_rpm(const struct axi_fan_control_data *ctl)
134 {
135 	const u32 tach = axi_ioread(ADI_REG_TACH_MEASUR, ctl);
136 
137 	if (tach == 0)
138 		/* should we return error, EAGAIN maybe? */
139 		return 0;
140 	/*
141 	 * The tacho period should be:
142 	 *      TACH = 60/(ppr * rpm), where rpm is revolutions per second
143 	 *      and ppr is pulses per revolution.
144 	 * Given the tacho period, we can multiply it by the input clock
145 	 * so that we know how many clocks we need to have this period.
146 	 * From this, we can derive the RPM value.
147 	 */
148 	return DIV_ROUND_CLOSEST(60 * ctl->clk_rate, ctl->ppr * tach);
149 }
150 
151 static int axi_fan_control_read_temp(struct device *dev, u32 attr, long *val)
152 {
153 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
154 	long raw_temp;
155 
156 	switch (attr) {
157 	case hwmon_temp_input:
158 		raw_temp = axi_ioread(ADI_REG_TEMPERATURE, ctl);
159 		/*
160 		 * The formula for the temperature is:
161 		 *      T = (ADC * 501.3743 / 2^bits) - 273.6777
162 		 * It's multiplied by 1000 to have millidegrees as
163 		 * specified by the hwmon sysfs interface.
164 		 */
165 		*val = ((raw_temp * 501374) >> 16) - 273677;
166 		return 0;
167 	default:
168 		return -ENOTSUPP;
169 	}
170 }
171 
172 static int axi_fan_control_read_fan(struct device *dev, u32 attr, long *val)
173 {
174 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
175 
176 	switch (attr) {
177 	case hwmon_fan_fault:
178 		*val = ctl->fan_fault;
179 		/* clear it now */
180 		ctl->fan_fault = 0;
181 		return 0;
182 	case hwmon_fan_input:
183 		*val = axi_fan_control_get_fan_rpm(ctl);
184 		return 0;
185 	default:
186 		return -ENOTSUPP;
187 	}
188 }
189 
190 static int axi_fan_control_read_pwm(struct device *dev, u32 attr, long *val)
191 {
192 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
193 
194 	switch (attr) {
195 	case hwmon_pwm_input:
196 		*val = axi_fan_control_get_pwm_duty(ctl);
197 		return 0;
198 	default:
199 		return -ENOTSUPP;
200 	}
201 }
202 
203 static int axi_fan_control_write_pwm(struct device *dev, u32 attr, long val)
204 {
205 	struct axi_fan_control_data *ctl = dev_get_drvdata(dev);
206 
207 	switch (attr) {
208 	case hwmon_pwm_input:
209 		return axi_fan_control_set_pwm_duty(val, ctl);
210 	default:
211 		return -ENOTSUPP;
212 	}
213 }
214 
215 static int axi_fan_control_read_labels(struct device *dev,
216 				       enum hwmon_sensor_types type,
217 				       u32 attr, int channel, const char **str)
218 {
219 	switch (type) {
220 	case hwmon_fan:
221 		*str = "FAN";
222 		return 0;
223 	case hwmon_temp:
224 		*str = "SYSMON4";
225 		return 0;
226 	default:
227 		return -ENOTSUPP;
228 	}
229 }
230 
231 static int axi_fan_control_read(struct device *dev,
232 				enum hwmon_sensor_types type,
233 				u32 attr, int channel, long *val)
234 {
235 	switch (type) {
236 	case hwmon_fan:
237 		return axi_fan_control_read_fan(dev, attr, val);
238 	case hwmon_pwm:
239 		return axi_fan_control_read_pwm(dev, attr, val);
240 	case hwmon_temp:
241 		return axi_fan_control_read_temp(dev, attr, val);
242 	default:
243 		return -ENOTSUPP;
244 	}
245 }
246 
247 static int axi_fan_control_write(struct device *dev,
248 				 enum hwmon_sensor_types type,
249 				 u32 attr, int channel, long val)
250 {
251 	switch (type) {
252 	case hwmon_pwm:
253 		return axi_fan_control_write_pwm(dev, attr, val);
254 	default:
255 		return -ENOTSUPP;
256 	}
257 }
258 
259 static umode_t axi_fan_control_fan_is_visible(const u32 attr)
260 {
261 	switch (attr) {
262 	case hwmon_fan_input:
263 	case hwmon_fan_fault:
264 	case hwmon_fan_label:
265 		return 0444;
266 	default:
267 		return 0;
268 	}
269 }
270 
271 static umode_t axi_fan_control_pwm_is_visible(const u32 attr)
272 {
273 	switch (attr) {
274 	case hwmon_pwm_input:
275 		return 0644;
276 	default:
277 		return 0;
278 	}
279 }
280 
281 static umode_t axi_fan_control_temp_is_visible(const u32 attr)
282 {
283 	switch (attr) {
284 	case hwmon_temp_input:
285 	case hwmon_temp_label:
286 		return 0444;
287 	default:
288 		return 0;
289 	}
290 }
291 
292 static umode_t axi_fan_control_is_visible(const void *data,
293 					  enum hwmon_sensor_types type,
294 					  u32 attr, int channel)
295 {
296 	switch (type) {
297 	case hwmon_fan:
298 		return axi_fan_control_fan_is_visible(attr);
299 	case hwmon_pwm:
300 		return axi_fan_control_pwm_is_visible(attr);
301 	case hwmon_temp:
302 		return axi_fan_control_temp_is_visible(attr);
303 	default:
304 		return 0;
305 	}
306 }
307 
308 /*
309  * This core has two main ways of changing the PWM duty cycle. It is done,
310  * either by a request from userspace (writing on pwm1_input) or by the
311  * core itself. When the change is done by the core, it will use predefined
312  * parameters to evaluate the tach signal and, on that case we cannot set them.
313  * On the other hand, when the request is done by the user, with some arbitrary
314  * value that the core does not now about, we have to provide the tach
315  * parameters so that, the core can evaluate the signal. On the IRQ handler we
316  * distinguish this by using the ADI_IRQ_SRC_TEMP_INCREASE interrupt. This tell
317  * us that the CORE requested a new duty cycle. After this, there is 5s delay
318  * on which the core waits for the fan rotation speed to stabilize. After this
319  * we get ADI_IRQ_SRC_PWM_CHANGED irq where we will decide if we need to set
320  * the tach parameters or not on the next tach measurement cycle (corresponding
321  * already to the ney duty cycle) based on the %ctl->hw_pwm_req flag.
322  */
323 static irqreturn_t axi_fan_control_irq_handler(int irq, void *data)
324 {
325 	struct axi_fan_control_data *ctl = (struct axi_fan_control_data *)data;
326 	u32 irq_pending = axi_ioread(ADI_REG_IRQ_PENDING, ctl);
327 	u32 clear_mask;
328 
329 	if (irq_pending & ADI_IRQ_SRC_TEMP_INCREASE)
330 		/* hardware requested a new pwm */
331 		ctl->hw_pwm_req = true;
332 
333 	if (irq_pending & ADI_IRQ_SRC_PWM_CHANGED) {
334 		/*
335 		 * if the pwm changes on behalf of software,
336 		 * we need to provide new tacho parameters to the core.
337 		 * Wait for the next measurement for that...
338 		 */
339 		if (!ctl->hw_pwm_req) {
340 			ctl->update_tacho_params = true;
341 		} else {
342 			ctl->hw_pwm_req = false;
343 			hwmon_notify_event(ctl->hdev, hwmon_pwm,
344 					   hwmon_pwm_input, 0);
345 		}
346 	}
347 
348 	if (irq_pending & ADI_IRQ_SRC_NEW_MEASUR) {
349 		if (ctl->update_tacho_params) {
350 			u32 new_tach = axi_ioread(ADI_REG_TACH_MEASUR, ctl);
351 			/* get 25% tolerance */
352 			u32 tach_tol = DIV_ROUND_CLOSEST(new_tach * 25, 100);
353 
354 			/* set new tacho parameters */
355 			axi_iowrite(new_tach, ADI_REG_TACH_PERIOD, ctl);
356 			axi_iowrite(tach_tol, ADI_REG_TACH_TOLERANCE, ctl);
357 			ctl->update_tacho_params = false;
358 		}
359 	}
360 
361 	if (irq_pending & ADI_IRQ_SRC_TACH_ERR)
362 		ctl->fan_fault = 1;
363 
364 	/* clear all interrupts */
365 	clear_mask = irq_pending & ADI_IRQ_SRC_MASK;
366 	axi_iowrite(clear_mask, ADI_REG_IRQ_PENDING, ctl);
367 
368 	return IRQ_HANDLED;
369 }
370 
371 static int axi_fan_control_init(struct axi_fan_control_data *ctl,
372 				const struct device *dev)
373 {
374 	int ret;
375 
376 	/* get fan pulses per revolution */
377 	ret = device_property_read_u32(dev, "pulses-per-revolution", &ctl->ppr);
378 	if (ret)
379 		return ret;
380 
381 	/* 1, 2 and 4 are the typical and accepted values */
382 	if (ctl->ppr != 1 && ctl->ppr != 2 && ctl->ppr != 4)
383 		return -EINVAL;
384 	/*
385 	 * Enable all IRQs
386 	 */
387 	axi_iowrite(ADI_IRQ_MASK_OUT_ALL &
388 		    ~(ADI_IRQ_SRC_NEW_MEASUR | ADI_IRQ_SRC_TACH_ERR |
389 		      ADI_IRQ_SRC_PWM_CHANGED | ADI_IRQ_SRC_TEMP_INCREASE),
390 		    ADI_REG_IRQ_MASK, ctl);
391 
392 	/* bring the device out of reset */
393 	axi_iowrite(0x01, ADI_REG_RSTN, ctl);
394 
395 	return ret;
396 }
397 
398 static const struct hwmon_channel_info * const axi_fan_control_info[] = {
399 	HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT),
400 	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT | HWMON_F_FAULT | HWMON_F_LABEL),
401 	HWMON_CHANNEL_INFO(temp, HWMON_T_INPUT | HWMON_T_LABEL),
402 	NULL
403 };
404 
405 static const struct hwmon_ops axi_fan_control_hwmon_ops = {
406 	.is_visible = axi_fan_control_is_visible,
407 	.read = axi_fan_control_read,
408 	.write = axi_fan_control_write,
409 	.read_string = axi_fan_control_read_labels,
410 };
411 
412 static const struct hwmon_chip_info axi_chip_info = {
413 	.ops = &axi_fan_control_hwmon_ops,
414 	.info = axi_fan_control_info,
415 };
416 
417 /* temperature threshold below which PWM should be 0% */
418 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point1_temp_hyst, axi_fan_control, ADI_REG_TEMP_00_H);
419 /* temperature threshold above which PWM should be 25% */
420 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point1_temp, axi_fan_control, ADI_REG_TEMP_25_L);
421 /* temperature threshold below which PWM should be 25% */
422 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point2_temp_hyst, axi_fan_control, ADI_REG_TEMP_25_H);
423 /* temperature threshold above which PWM should be 50% */
424 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point2_temp, axi_fan_control, ADI_REG_TEMP_50_L);
425 /* temperature threshold below which PWM should be 50% */
426 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point3_temp_hyst, axi_fan_control, ADI_REG_TEMP_50_H);
427 /* temperature threshold above which PWM should be 75% */
428 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point3_temp, axi_fan_control, ADI_REG_TEMP_75_L);
429 /* temperature threshold below which PWM should be 75% */
430 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point4_temp_hyst, axi_fan_control, ADI_REG_TEMP_75_H);
431 /* temperature threshold above which PWM should be 100% */
432 static SENSOR_DEVICE_ATTR_RW(pwm1_auto_point4_temp, axi_fan_control, ADI_REG_TEMP_100_L);
433 
434 static struct attribute *axi_fan_control_attrs[] = {
435 	&sensor_dev_attr_pwm1_auto_point1_temp_hyst.dev_attr.attr,
436 	&sensor_dev_attr_pwm1_auto_point1_temp.dev_attr.attr,
437 	&sensor_dev_attr_pwm1_auto_point2_temp_hyst.dev_attr.attr,
438 	&sensor_dev_attr_pwm1_auto_point2_temp.dev_attr.attr,
439 	&sensor_dev_attr_pwm1_auto_point3_temp_hyst.dev_attr.attr,
440 	&sensor_dev_attr_pwm1_auto_point3_temp.dev_attr.attr,
441 	&sensor_dev_attr_pwm1_auto_point4_temp_hyst.dev_attr.attr,
442 	&sensor_dev_attr_pwm1_auto_point4_temp.dev_attr.attr,
443 	NULL,
444 };
445 ATTRIBUTE_GROUPS(axi_fan_control);
446 
447 static int axi_fan_control_probe(struct platform_device *pdev)
448 {
449 	struct axi_fan_control_data *ctl;
450 	struct clk *clk;
451 	const unsigned int *id;
452 	const char *name = "axi_fan_control";
453 	u32 version;
454 	int ret;
455 
456 	id = device_get_match_data(&pdev->dev);
457 	if (!id)
458 		return -EINVAL;
459 
460 	ctl = devm_kzalloc(&pdev->dev, sizeof(*ctl), GFP_KERNEL);
461 	if (!ctl)
462 		return -ENOMEM;
463 
464 	ctl->base = devm_platform_ioremap_resource(pdev, 0);
465 	if (IS_ERR(ctl->base))
466 		return PTR_ERR(ctl->base);
467 
468 	clk = devm_clk_get_enabled(&pdev->dev, NULL);
469 	if (IS_ERR(clk))
470 		return dev_err_probe(&pdev->dev, PTR_ERR(clk),
471 				     "clk_get failed\n");
472 
473 	ctl->clk_rate = clk_get_rate(clk);
474 	if (!ctl->clk_rate)
475 		return -EINVAL;
476 
477 	version = axi_ioread(ADI_AXI_REG_VERSION, ctl);
478 	if (ADI_AXI_PCORE_VER_MAJOR(version) !=
479 	    ADI_AXI_PCORE_VER_MAJOR((*id)))
480 		return dev_err_probe(&pdev->dev, -ENODEV,
481 				     "Major version mismatch. Expected %d.%.2d.%c, Reported %d.%.2d.%c\n",
482 				     ADI_AXI_PCORE_VER_MAJOR(*id),
483 				     ADI_AXI_PCORE_VER_MINOR(*id),
484 				     ADI_AXI_PCORE_VER_PATCH(*id),
485 				     ADI_AXI_PCORE_VER_MAJOR(version),
486 				     ADI_AXI_PCORE_VER_MINOR(version),
487 				     ADI_AXI_PCORE_VER_PATCH(version));
488 
489 	ret = axi_fan_control_init(ctl, &pdev->dev);
490 	if (ret)
491 		return dev_err_probe(&pdev->dev, ret,
492 				     "Failed to initialize device\n");
493 
494 	ctl->hdev = devm_hwmon_device_register_with_info(&pdev->dev,
495 							 name,
496 							 ctl,
497 							 &axi_chip_info,
498 							 axi_fan_control_groups);
499 
500 	if (IS_ERR(ctl->hdev))
501 		return PTR_ERR(ctl->hdev);
502 
503 	ctl->irq = platform_get_irq(pdev, 0);
504 	if (ctl->irq < 0)
505 		return ctl->irq;
506 
507 	ret = devm_request_threaded_irq(&pdev->dev, ctl->irq, NULL,
508 					axi_fan_control_irq_handler,
509 					IRQF_ONESHOT | IRQF_TRIGGER_HIGH,
510 					pdev->driver_override, ctl);
511 	if (ret)
512 		return dev_err_probe(&pdev->dev, ret,
513 				     "failed to request an irq\n");
514 
515 	return 0;
516 }
517 
518 static const u32 version_1_0_0 = ADI_AXI_PCORE_VER(1, 0, 'a');
519 
520 static const struct of_device_id axi_fan_control_of_match[] = {
521 	{ .compatible = "adi,axi-fan-control-1.00.a",
522 		.data = (void *)&version_1_0_0},
523 	{},
524 };
525 MODULE_DEVICE_TABLE(of, axi_fan_control_of_match);
526 
527 static struct platform_driver axi_fan_control_driver = {
528 	.driver = {
529 		.name = "axi_fan_control_driver",
530 		.of_match_table = axi_fan_control_of_match,
531 	},
532 	.probe = axi_fan_control_probe,
533 };
534 module_platform_driver(axi_fan_control_driver);
535 
536 MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
537 MODULE_DESCRIPTION("Analog Devices Fan Control HDL CORE driver");
538 MODULE_LICENSE("GPL");
539