1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Mellanox hotplug driver
4  *
5  * Copyright (C) 2016-2020 Mellanox Technologies
6  */
7 
8 #include <linux/bitops.h>
9 #include <linux/device.h>
10 #include <linux/hwmon.h>
11 #include <linux/hwmon-sysfs.h>
12 #include <linux/i2c.h>
13 #include <linux/interrupt.h>
14 #include <linux/module.h>
15 #include <linux/platform_data/mlxreg.h>
16 #include <linux/platform_device.h>
17 #include <linux/spinlock.h>
18 #include <linux/string_helpers.h>
19 #include <linux/regmap.h>
20 #include <linux/workqueue.h>
21 
22 /* Offset of event and mask registers from status register. */
23 #define MLXREG_HOTPLUG_EVENT_OFF	1
24 #define MLXREG_HOTPLUG_MASK_OFF		2
25 #define MLXREG_HOTPLUG_AGGR_MASK_OFF	1
26 
27 /* ASIC good health mask. */
28 #define MLXREG_HOTPLUG_GOOD_HEALTH_MASK	0x02
29 
30 #define MLXREG_HOTPLUG_ATTRS_MAX	128
31 #define MLXREG_HOTPLUG_NOT_ASSERT	3
32 
33 /**
34  * struct mlxreg_hotplug_priv_data - platform private data:
35  * @irq: platform device interrupt number;
36  * @dev: basic device;
37  * @pdev: platform device;
38  * @plat: platform data;
39  * @regmap: register map handle;
40  * @dwork_irq: delayed work template;
41  * @lock: spin lock;
42  * @hwmon: hwmon device;
43  * @mlxreg_hotplug_attr: sysfs attributes array;
44  * @mlxreg_hotplug_dev_attr: sysfs sensor device attribute array;
45  * @group: sysfs attribute group;
46  * @groups: list of sysfs attribute group for hwmon registration;
47  * @cell: location of top aggregation interrupt register;
48  * @mask: top aggregation interrupt common mask;
49  * @aggr_cache: last value of aggregation register status;
50  * @after_probe: flag indication probing completion;
51  * @not_asserted: number of entries in workqueue with no signal assertion;
52  */
53 struct mlxreg_hotplug_priv_data {
54 	int irq;
55 	struct device *dev;
56 	struct platform_device *pdev;
57 	struct mlxreg_hotplug_platform_data *plat;
58 	struct regmap *regmap;
59 	struct delayed_work dwork_irq;
60 	spinlock_t lock; /* sync with interrupt */
61 	struct device *hwmon;
62 	struct attribute *mlxreg_hotplug_attr[MLXREG_HOTPLUG_ATTRS_MAX + 1];
63 	struct sensor_device_attribute_2
64 			mlxreg_hotplug_dev_attr[MLXREG_HOTPLUG_ATTRS_MAX];
65 	struct attribute_group group;
66 	const struct attribute_group *groups[2];
67 	u32 cell;
68 	u32 mask;
69 	u32 aggr_cache;
70 	bool after_probe;
71 	u8 not_asserted;
72 };
73 
74 /* Environment variables array for udev. */
75 static char *mlxreg_hotplug_udev_envp[] = { NULL, NULL };
76 
77 static int
78 mlxreg_hotplug_udev_event_send(struct kobject *kobj,
79 			       struct mlxreg_core_data *data, bool action)
80 {
81 	char event_str[MLXREG_CORE_LABEL_MAX_SIZE + 2];
82 	char label[MLXREG_CORE_LABEL_MAX_SIZE] = { 0 };
83 
84 	mlxreg_hotplug_udev_envp[0] = event_str;
85 	string_upper(label, data->label);
86 	snprintf(event_str, MLXREG_CORE_LABEL_MAX_SIZE, "%s=%d", label, !!action);
87 
88 	return kobject_uevent_env(kobj, KOBJ_CHANGE, mlxreg_hotplug_udev_envp);
89 }
90 
91 static void
92 mlxreg_hotplug_pdata_export(void *pdata, void *regmap)
93 {
94 	struct mlxreg_core_hotplug_platform_data *dev_pdata = pdata;
95 
96 	/* Export regmap to underlying device. */
97 	dev_pdata->regmap = regmap;
98 }
99 
100 static int mlxreg_hotplug_device_create(struct mlxreg_hotplug_priv_data *priv,
101 					struct mlxreg_core_data *data,
102 					enum mlxreg_hotplug_kind kind)
103 {
104 	struct i2c_board_info *brdinfo = data->hpdev.brdinfo;
105 	struct mlxreg_core_hotplug_platform_data *pdata;
106 	struct i2c_client *client;
107 
108 	/* Notify user by sending hwmon uevent. */
109 	mlxreg_hotplug_udev_event_send(&priv->hwmon->kobj, data, true);
110 
111 	/*
112 	 * Return if adapter number is negative. It could be in case hotplug
113 	 * event is not associated with hotplug device.
114 	 */
115 	if (data->hpdev.nr < 0 && data->hpdev.action != MLXREG_HOTPLUG_DEVICE_NO_ACTION)
116 		return 0;
117 
118 	pdata = dev_get_platdata(&priv->pdev->dev);
119 	switch (data->hpdev.action) {
120 	case MLXREG_HOTPLUG_DEVICE_DEFAULT_ACTION:
121 		data->hpdev.adapter = i2c_get_adapter(data->hpdev.nr +
122 						      pdata->shift_nr);
123 		if (!data->hpdev.adapter) {
124 			dev_err(priv->dev, "Failed to get adapter for bus %d\n",
125 				data->hpdev.nr + pdata->shift_nr);
126 			return -EFAULT;
127 		}
128 
129 		/* Export platform data to underlying device. */
130 		if (brdinfo->platform_data)
131 			mlxreg_hotplug_pdata_export(brdinfo->platform_data, pdata->regmap);
132 
133 		client = i2c_new_client_device(data->hpdev.adapter,
134 					       brdinfo);
135 		if (IS_ERR(client)) {
136 			dev_err(priv->dev, "Failed to create client %s at bus %d at addr 0x%02x\n",
137 				brdinfo->type, data->hpdev.nr +
138 				pdata->shift_nr, brdinfo->addr);
139 
140 			i2c_put_adapter(data->hpdev.adapter);
141 			data->hpdev.adapter = NULL;
142 			return PTR_ERR(client);
143 		}
144 
145 		data->hpdev.client = client;
146 		break;
147 	case MLXREG_HOTPLUG_DEVICE_PLATFORM_ACTION:
148 		/* Export platform data to underlying device. */
149 		if (data->hpdev.brdinfo && data->hpdev.brdinfo->platform_data)
150 			mlxreg_hotplug_pdata_export(data->hpdev.brdinfo->platform_data,
151 						    pdata->regmap);
152 		/* Pass parent hotplug device handle to underlying device. */
153 		data->notifier = data->hpdev.notifier;
154 		data->hpdev.pdev = platform_device_register_resndata(&priv->pdev->dev,
155 								     brdinfo->type,
156 								     data->hpdev.nr,
157 								     NULL, 0, data,
158 								     sizeof(*data));
159 		if (IS_ERR(data->hpdev.pdev))
160 			return PTR_ERR(data->hpdev.pdev);
161 
162 		break;
163 	default:
164 		break;
165 	}
166 
167 	if (data->hpdev.notifier && data->hpdev.notifier->user_handler)
168 		return data->hpdev.notifier->user_handler(data->hpdev.notifier->handle, kind, 1);
169 
170 	return 0;
171 }
172 
173 static void
174 mlxreg_hotplug_device_destroy(struct mlxreg_hotplug_priv_data *priv,
175 			      struct mlxreg_core_data *data,
176 			      enum mlxreg_hotplug_kind kind)
177 {
178 	/* Notify user by sending hwmon uevent. */
179 	mlxreg_hotplug_udev_event_send(&priv->hwmon->kobj, data, false);
180 	if (data->hpdev.notifier && data->hpdev.notifier->user_handler)
181 		data->hpdev.notifier->user_handler(data->hpdev.notifier->handle, kind, 0);
182 
183 	switch (data->hpdev.action) {
184 	case MLXREG_HOTPLUG_DEVICE_DEFAULT_ACTION:
185 		if (data->hpdev.client) {
186 			i2c_unregister_device(data->hpdev.client);
187 			data->hpdev.client = NULL;
188 		}
189 
190 		if (data->hpdev.adapter) {
191 			i2c_put_adapter(data->hpdev.adapter);
192 			data->hpdev.adapter = NULL;
193 		}
194 		break;
195 	case MLXREG_HOTPLUG_DEVICE_PLATFORM_ACTION:
196 		if (data->hpdev.pdev)
197 			platform_device_unregister(data->hpdev.pdev);
198 		break;
199 	default:
200 		break;
201 	}
202 }
203 
204 static ssize_t mlxreg_hotplug_attr_show(struct device *dev,
205 					struct device_attribute *attr,
206 					char *buf)
207 {
208 	struct mlxreg_hotplug_priv_data *priv = dev_get_drvdata(dev);
209 	struct mlxreg_core_hotplug_platform_data *pdata;
210 	int index = to_sensor_dev_attr_2(attr)->index;
211 	int nr = to_sensor_dev_attr_2(attr)->nr;
212 	struct mlxreg_core_item *item;
213 	struct mlxreg_core_data *data;
214 	u32 regval;
215 	int ret;
216 
217 	pdata = dev_get_platdata(&priv->pdev->dev);
218 	item = pdata->items + nr;
219 	data = item->data + index;
220 
221 	ret = regmap_read(priv->regmap, data->reg, &regval);
222 	if (ret)
223 		return ret;
224 
225 	if (item->health) {
226 		regval &= data->mask;
227 	} else {
228 		/* Bit = 0 : functional if item->inversed is true. */
229 		if (item->inversed)
230 			regval = !(regval & data->mask);
231 		else
232 			regval = !!(regval & data->mask);
233 	}
234 
235 	return sprintf(buf, "%u\n", regval);
236 }
237 
238 #define PRIV_ATTR(i) priv->mlxreg_hotplug_attr[i]
239 #define PRIV_DEV_ATTR(i) priv->mlxreg_hotplug_dev_attr[i]
240 
241 static int mlxreg_hotplug_item_label_index_get(u32 mask, u32 bit)
242 {
243 	int i, j;
244 
245 	for (i = 0, j = -1; i <= bit; i++) {
246 		if (mask & BIT(i))
247 			j++;
248 	}
249 	return j;
250 }
251 
252 static int mlxreg_hotplug_attr_init(struct mlxreg_hotplug_priv_data *priv)
253 {
254 	struct mlxreg_core_hotplug_platform_data *pdata;
255 	struct mlxreg_core_item *item;
256 	struct mlxreg_core_data *data;
257 	unsigned long mask;
258 	u32 regval;
259 	int num_attrs = 0, id = 0, i, j, k, count, ret;
260 
261 	pdata = dev_get_platdata(&priv->pdev->dev);
262 	item = pdata->items;
263 
264 	/* Go over all kinds of items - psu, pwr, fan. */
265 	for (i = 0; i < pdata->counter; i++, item++) {
266 		if (item->capability) {
267 			/*
268 			 * Read group capability register to get actual number
269 			 * of interrupt capable components and set group mask
270 			 * accordingly.
271 			 */
272 			ret = regmap_read(priv->regmap, item->capability,
273 					  &regval);
274 			if (ret)
275 				return ret;
276 
277 			item->mask = GENMASK((regval & item->mask) - 1, 0);
278 		}
279 
280 		data = item->data;
281 
282 		/* Go over all unmasked units within item. */
283 		mask = item->mask;
284 		k = 0;
285 		count = item->ind ? item->ind : item->count;
286 		for_each_set_bit(j, &mask, count) {
287 			if (data->capability) {
288 				/*
289 				 * Read capability register and skip non
290 				 * relevant attributes.
291 				 */
292 				ret = regmap_read(priv->regmap,
293 						  data->capability, &regval);
294 				if (ret)
295 					return ret;
296 
297 				if (!(regval & data->bit)) {
298 					data++;
299 					continue;
300 				}
301 			}
302 
303 			PRIV_ATTR(id) = &PRIV_DEV_ATTR(id).dev_attr.attr;
304 			PRIV_ATTR(id)->name = devm_kasprintf(&priv->pdev->dev,
305 							     GFP_KERNEL,
306 							     data->label);
307 			if (!PRIV_ATTR(id)->name) {
308 				dev_err(priv->dev, "Memory allocation failed for attr %d.\n",
309 					id);
310 				return -ENOMEM;
311 			}
312 
313 			PRIV_DEV_ATTR(id).dev_attr.attr.name =
314 							PRIV_ATTR(id)->name;
315 			PRIV_DEV_ATTR(id).dev_attr.attr.mode = 0444;
316 			PRIV_DEV_ATTR(id).dev_attr.show =
317 						mlxreg_hotplug_attr_show;
318 			PRIV_DEV_ATTR(id).nr = i;
319 			PRIV_DEV_ATTR(id).index = k;
320 			sysfs_attr_init(&PRIV_DEV_ATTR(id).dev_attr.attr);
321 			data++;
322 			id++;
323 			k++;
324 		}
325 		num_attrs += k;
326 	}
327 
328 	priv->group.attrs = devm_kcalloc(&priv->pdev->dev,
329 					 num_attrs,
330 					 sizeof(struct attribute *),
331 					 GFP_KERNEL);
332 	if (!priv->group.attrs)
333 		return -ENOMEM;
334 
335 	priv->group.attrs = priv->mlxreg_hotplug_attr;
336 	priv->groups[0] = &priv->group;
337 	priv->groups[1] = NULL;
338 
339 	return 0;
340 }
341 
342 static void
343 mlxreg_hotplug_work_helper(struct mlxreg_hotplug_priv_data *priv,
344 			   struct mlxreg_core_item *item)
345 {
346 	struct mlxreg_core_data *data;
347 	unsigned long asserted;
348 	u32 regval, bit;
349 	int ret;
350 
351 	/*
352 	 * Validate if item related to received signal type is valid.
353 	 * It should never happen, excepted the situation when some
354 	 * piece of hardware is broken. In such situation just produce
355 	 * error message and return. Caller must continue to handle the
356 	 * signals from other devices if any.
357 	 */
358 	if (unlikely(!item)) {
359 		dev_err(priv->dev, "False signal: at offset:mask 0x%02x:0x%02x.\n",
360 			item->reg, item->mask);
361 
362 		return;
363 	}
364 
365 	/* Mask event. */
366 	ret = regmap_write(priv->regmap, item->reg + MLXREG_HOTPLUG_MASK_OFF,
367 			   0);
368 	if (ret)
369 		goto out;
370 
371 	/* Read status. */
372 	ret = regmap_read(priv->regmap, item->reg, &regval);
373 	if (ret)
374 		goto out;
375 
376 	/* Set asserted bits and save last status. */
377 	regval &= item->mask;
378 	asserted = item->cache ^ regval;
379 	item->cache = regval;
380 	for_each_set_bit(bit, &asserted, 8) {
381 		int pos;
382 
383 		pos = mlxreg_hotplug_item_label_index_get(item->mask, bit);
384 		if (pos < 0)
385 			goto out;
386 
387 		data = item->data + pos;
388 		if (regval & BIT(bit)) {
389 			if (item->inversed)
390 				mlxreg_hotplug_device_destroy(priv, data, item->kind);
391 			else
392 				mlxreg_hotplug_device_create(priv, data, item->kind);
393 		} else {
394 			if (item->inversed)
395 				mlxreg_hotplug_device_create(priv, data, item->kind);
396 			else
397 				mlxreg_hotplug_device_destroy(priv, data, item->kind);
398 		}
399 	}
400 
401 	/* Acknowledge event. */
402 	ret = regmap_write(priv->regmap, item->reg + MLXREG_HOTPLUG_EVENT_OFF,
403 			   0);
404 	if (ret)
405 		goto out;
406 
407 	/* Unmask event. */
408 	ret = regmap_write(priv->regmap, item->reg + MLXREG_HOTPLUG_MASK_OFF,
409 			   item->mask);
410 
411  out:
412 	if (ret)
413 		dev_err(priv->dev, "Failed to complete workqueue.\n");
414 }
415 
416 static void
417 mlxreg_hotplug_health_work_helper(struct mlxreg_hotplug_priv_data *priv,
418 				  struct mlxreg_core_item *item)
419 {
420 	struct mlxreg_core_data *data = item->data;
421 	u32 regval;
422 	int i, ret = 0;
423 
424 	for (i = 0; i < item->count; i++, data++) {
425 		/* Mask event. */
426 		ret = regmap_write(priv->regmap, data->reg +
427 				   MLXREG_HOTPLUG_MASK_OFF, 0);
428 		if (ret)
429 			goto out;
430 
431 		/* Read status. */
432 		ret = regmap_read(priv->regmap, data->reg, &regval);
433 		if (ret)
434 			goto out;
435 
436 		regval &= data->mask;
437 
438 		if (item->cache == regval)
439 			goto ack_event;
440 
441 		/*
442 		 * ASIC health indication is provided through two bits. Bits
443 		 * value 0x2 indicates that ASIC reached the good health, value
444 		 * 0x0 indicates ASIC the bad health or dormant state and value
445 		 * 0x3 indicates the booting state. During ASIC reset it should
446 		 * pass the following states: dormant -> booting -> good.
447 		 */
448 		if (regval == MLXREG_HOTPLUG_GOOD_HEALTH_MASK) {
449 			if (!data->attached) {
450 				/*
451 				 * ASIC is in steady state. Connect associated
452 				 * device, if configured.
453 				 */
454 				mlxreg_hotplug_device_create(priv, data, item->kind);
455 				data->attached = true;
456 			}
457 		} else {
458 			if (data->attached) {
459 				/*
460 				 * ASIC health is failed after ASIC has been
461 				 * in steady state. Disconnect associated
462 				 * device, if it has been connected.
463 				 */
464 				mlxreg_hotplug_device_destroy(priv, data, item->kind);
465 				data->attached = false;
466 				data->health_cntr = 0;
467 			}
468 		}
469 		item->cache = regval;
470 ack_event:
471 		/* Acknowledge event. */
472 		ret = regmap_write(priv->regmap, data->reg +
473 				   MLXREG_HOTPLUG_EVENT_OFF, 0);
474 		if (ret)
475 			goto out;
476 
477 		/* Unmask event. */
478 		ret = regmap_write(priv->regmap, data->reg +
479 				   MLXREG_HOTPLUG_MASK_OFF, data->mask);
480 		if (ret)
481 			goto out;
482 	}
483 
484  out:
485 	if (ret)
486 		dev_err(priv->dev, "Failed to complete workqueue.\n");
487 }
488 
489 /*
490  * mlxreg_hotplug_work_handler - performs traversing of device interrupt
491  * registers according to the below hierarchy schema:
492  *
493  *				Aggregation registers (status/mask)
494  * PSU registers:		*---*
495  * *-----------------*		|   |
496  * |status/event/mask|----->    | * |
497  * *-----------------*		|   |
498  * Power registers:		|   |
499  * *-----------------*		|   |
500  * |status/event/mask|----->    | * |
501  * *-----------------*		|   |
502  * FAN registers:		|   |--> CPU
503  * *-----------------*		|   |
504  * |status/event/mask|----->    | * |
505  * *-----------------*		|   |
506  * ASIC registers:		|   |
507  * *-----------------*		|   |
508  * |status/event/mask|----->    | * |
509  * *-----------------*		|   |
510  *				*---*
511  *
512  * In case some system changed are detected: FAN in/out, PSU in/out, power
513  * cable attached/detached, ASIC health good/bad, relevant device is created
514  * or destroyed.
515  */
516 static void mlxreg_hotplug_work_handler(struct work_struct *work)
517 {
518 	struct mlxreg_core_hotplug_platform_data *pdata;
519 	struct mlxreg_hotplug_priv_data *priv;
520 	struct mlxreg_core_item *item;
521 	u32 regval, aggr_asserted;
522 	unsigned long flags;
523 	int i, ret;
524 
525 	priv = container_of(work, struct mlxreg_hotplug_priv_data,
526 			    dwork_irq.work);
527 	pdata = dev_get_platdata(&priv->pdev->dev);
528 	item = pdata->items;
529 
530 	/* Mask aggregation event. */
531 	ret = regmap_write(priv->regmap, pdata->cell +
532 			   MLXREG_HOTPLUG_AGGR_MASK_OFF, 0);
533 	if (ret < 0)
534 		goto out;
535 
536 	/* Read aggregation status. */
537 	ret = regmap_read(priv->regmap, pdata->cell, &regval);
538 	if (ret)
539 		goto out;
540 
541 	regval &= pdata->mask;
542 	aggr_asserted = priv->aggr_cache ^ regval;
543 	priv->aggr_cache = regval;
544 
545 	/*
546 	 * Handler is invoked, but no assertion is detected at top aggregation
547 	 * status level. Set aggr_asserted to mask value to allow handler extra
548 	 * run over all relevant signals to recover any missed signal.
549 	 */
550 	if (priv->not_asserted == MLXREG_HOTPLUG_NOT_ASSERT) {
551 		priv->not_asserted = 0;
552 		aggr_asserted = pdata->mask;
553 	}
554 	if (!aggr_asserted)
555 		goto unmask_event;
556 
557 	/* Handle topology and health configuration changes. */
558 	for (i = 0; i < pdata->counter; i++, item++) {
559 		if (aggr_asserted & item->aggr_mask) {
560 			if (item->health)
561 				mlxreg_hotplug_health_work_helper(priv, item);
562 			else
563 				mlxreg_hotplug_work_helper(priv, item);
564 		}
565 	}
566 
567 	spin_lock_irqsave(&priv->lock, flags);
568 
569 	/*
570 	 * It is possible, that some signals have been inserted, while
571 	 * interrupt has been masked by mlxreg_hotplug_work_handler. In this
572 	 * case such signals will be missed. In order to handle these signals
573 	 * delayed work is canceled and work task re-scheduled for immediate
574 	 * execution. It allows to handle missed signals, if any. In other case
575 	 * work handler just validates that no new signals have been received
576 	 * during masking.
577 	 */
578 	cancel_delayed_work(&priv->dwork_irq);
579 	schedule_delayed_work(&priv->dwork_irq, 0);
580 
581 	spin_unlock_irqrestore(&priv->lock, flags);
582 
583 	return;
584 
585 unmask_event:
586 	priv->not_asserted++;
587 	/* Unmask aggregation event (no need acknowledge). */
588 	ret = regmap_write(priv->regmap, pdata->cell +
589 			   MLXREG_HOTPLUG_AGGR_MASK_OFF, pdata->mask);
590 
591  out:
592 	if (ret)
593 		dev_err(priv->dev, "Failed to complete workqueue.\n");
594 }
595 
596 static int mlxreg_hotplug_set_irq(struct mlxreg_hotplug_priv_data *priv)
597 {
598 	struct mlxreg_core_hotplug_platform_data *pdata;
599 	struct mlxreg_core_item *item;
600 	struct mlxreg_core_data *data;
601 	u32 regval;
602 	int i, j, ret;
603 
604 	pdata = dev_get_platdata(&priv->pdev->dev);
605 	item = pdata->items;
606 
607 	for (i = 0; i < pdata->counter; i++, item++) {
608 		/* Clear group presense event. */
609 		ret = regmap_write(priv->regmap, item->reg +
610 				   MLXREG_HOTPLUG_EVENT_OFF, 0);
611 		if (ret)
612 			goto out;
613 
614 		/*
615 		 * Verify if hardware configuration requires to disable
616 		 * interrupt capability for some of components.
617 		 */
618 		data = item->data;
619 		for (j = 0; j < item->count; j++, data++) {
620 			/* Verify if the attribute has capability register. */
621 			if (data->capability) {
622 				/* Read capability register. */
623 				ret = regmap_read(priv->regmap,
624 						  data->capability, &regval);
625 				if (ret)
626 					goto out;
627 
628 				if (!(regval & data->bit))
629 					item->mask &= ~BIT(j);
630 			}
631 		}
632 
633 		/* Set group initial status as mask and unmask group event. */
634 		if (item->inversed) {
635 			item->cache = item->mask;
636 			ret = regmap_write(priv->regmap, item->reg +
637 					   MLXREG_HOTPLUG_MASK_OFF,
638 					   item->mask);
639 			if (ret)
640 				goto out;
641 		}
642 	}
643 
644 	/* Keep aggregation initial status as zero and unmask events. */
645 	ret = regmap_write(priv->regmap, pdata->cell +
646 			   MLXREG_HOTPLUG_AGGR_MASK_OFF, pdata->mask);
647 	if (ret)
648 		goto out;
649 
650 	/* Keep low aggregation initial status as zero and unmask events. */
651 	if (pdata->cell_low) {
652 		ret = regmap_write(priv->regmap, pdata->cell_low +
653 				   MLXREG_HOTPLUG_AGGR_MASK_OFF,
654 				   pdata->mask_low);
655 		if (ret)
656 			goto out;
657 	}
658 
659 	/* Invoke work handler for initializing hot plug devices setting. */
660 	mlxreg_hotplug_work_handler(&priv->dwork_irq.work);
661 
662  out:
663 	if (ret)
664 		dev_err(priv->dev, "Failed to set interrupts.\n");
665 	enable_irq(priv->irq);
666 	return ret;
667 }
668 
669 static void mlxreg_hotplug_unset_irq(struct mlxreg_hotplug_priv_data *priv)
670 {
671 	struct mlxreg_core_hotplug_platform_data *pdata;
672 	struct mlxreg_core_item *item;
673 	struct mlxreg_core_data *data;
674 	int count, i, j;
675 
676 	pdata = dev_get_platdata(&priv->pdev->dev);
677 	item = pdata->items;
678 	disable_irq(priv->irq);
679 	cancel_delayed_work_sync(&priv->dwork_irq);
680 
681 	/* Mask low aggregation event, if defined. */
682 	if (pdata->cell_low)
683 		regmap_write(priv->regmap, pdata->cell_low +
684 			     MLXREG_HOTPLUG_AGGR_MASK_OFF, 0);
685 
686 	/* Mask aggregation event. */
687 	regmap_write(priv->regmap, pdata->cell + MLXREG_HOTPLUG_AGGR_MASK_OFF,
688 		     0);
689 
690 	/* Clear topology configurations. */
691 	for (i = 0; i < pdata->counter; i++, item++) {
692 		data = item->data;
693 		/* Mask group presense event. */
694 		regmap_write(priv->regmap, data->reg + MLXREG_HOTPLUG_MASK_OFF,
695 			     0);
696 		/* Clear group presense event. */
697 		regmap_write(priv->regmap, data->reg +
698 			     MLXREG_HOTPLUG_EVENT_OFF, 0);
699 
700 		/* Remove all the attached devices in group. */
701 		count = item->count;
702 		for (j = 0; j < count; j++, data++)
703 			mlxreg_hotplug_device_destroy(priv, data, item->kind);
704 	}
705 }
706 
707 static irqreturn_t mlxreg_hotplug_irq_handler(int irq, void *dev)
708 {
709 	struct mlxreg_hotplug_priv_data *priv;
710 
711 	priv = (struct mlxreg_hotplug_priv_data *)dev;
712 
713 	/* Schedule work task for immediate execution.*/
714 	schedule_delayed_work(&priv->dwork_irq, 0);
715 
716 	return IRQ_HANDLED;
717 }
718 
719 static int mlxreg_hotplug_probe(struct platform_device *pdev)
720 {
721 	struct mlxreg_core_hotplug_platform_data *pdata;
722 	struct mlxreg_hotplug_priv_data *priv;
723 	struct i2c_adapter *deferred_adap;
724 	int err;
725 
726 	pdata = dev_get_platdata(&pdev->dev);
727 	if (!pdata) {
728 		dev_err(&pdev->dev, "Failed to get platform data.\n");
729 		return -EINVAL;
730 	}
731 
732 	/* Defer probing if the necessary adapter is not configured yet. */
733 	deferred_adap = i2c_get_adapter(pdata->deferred_nr);
734 	if (!deferred_adap)
735 		return -EPROBE_DEFER;
736 	i2c_put_adapter(deferred_adap);
737 
738 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
739 	if (!priv)
740 		return -ENOMEM;
741 
742 	if (pdata->irq) {
743 		priv->irq = pdata->irq;
744 	} else {
745 		priv->irq = platform_get_irq(pdev, 0);
746 		if (priv->irq < 0)
747 			return priv->irq;
748 	}
749 
750 	priv->regmap = pdata->regmap;
751 	priv->dev = pdev->dev.parent;
752 	priv->pdev = pdev;
753 
754 	err = devm_request_irq(&pdev->dev, priv->irq,
755 			       mlxreg_hotplug_irq_handler, IRQF_TRIGGER_FALLING
756 			       | IRQF_SHARED, "mlxreg-hotplug", priv);
757 	if (err) {
758 		dev_err(&pdev->dev, "Failed to request irq: %d\n", err);
759 		return err;
760 	}
761 
762 	disable_irq(priv->irq);
763 	spin_lock_init(&priv->lock);
764 	INIT_DELAYED_WORK(&priv->dwork_irq, mlxreg_hotplug_work_handler);
765 	dev_set_drvdata(&pdev->dev, priv);
766 
767 	err = mlxreg_hotplug_attr_init(priv);
768 	if (err) {
769 		dev_err(&pdev->dev, "Failed to allocate attributes: %d\n",
770 			err);
771 		return err;
772 	}
773 
774 	priv->hwmon = devm_hwmon_device_register_with_groups(&pdev->dev,
775 					"mlxreg_hotplug", priv, priv->groups);
776 	if (IS_ERR(priv->hwmon)) {
777 		dev_err(&pdev->dev, "Failed to register hwmon device %ld\n",
778 			PTR_ERR(priv->hwmon));
779 		return PTR_ERR(priv->hwmon);
780 	}
781 
782 	/* Perform initial interrupts setup. */
783 	mlxreg_hotplug_set_irq(priv);
784 	priv->after_probe = true;
785 
786 	return 0;
787 }
788 
789 static int mlxreg_hotplug_remove(struct platform_device *pdev)
790 {
791 	struct mlxreg_hotplug_priv_data *priv = dev_get_drvdata(&pdev->dev);
792 
793 	/* Clean interrupts setup. */
794 	mlxreg_hotplug_unset_irq(priv);
795 	devm_free_irq(&pdev->dev, priv->irq, priv);
796 
797 	return 0;
798 }
799 
800 static struct platform_driver mlxreg_hotplug_driver = {
801 	.driver = {
802 		.name = "mlxreg-hotplug",
803 	},
804 	.probe = mlxreg_hotplug_probe,
805 	.remove = mlxreg_hotplug_remove,
806 };
807 
808 module_platform_driver(mlxreg_hotplug_driver);
809 
810 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
811 MODULE_DESCRIPTION("Mellanox regmap hotplug platform driver");
812 MODULE_LICENSE("Dual BSD/GPL");
813 MODULE_ALIAS("platform:mlxreg-hotplug");
814