1 files changed, 813 insertions, 0 deletions

diff --git a/drivers/platform/mellanox/mlxreg-hotplug.c b/drivers/platform/mellanox/mlxreg-hotplug.c
new file mode 100644
index 0000000000..eb5ad35274
--- /dev/null
+++ b/drivers/platform/mellanox/mlxreg-hotplug.c
@@ -0,0 +1,813 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Mellanox hotplug driver
+ *
+ * Copyright (C) 2016-2020 Mellanox Technologies
+ */
+
+#include <linux/bitops.h>
+#include <linux/device.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_data/mlxreg.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/string_helpers.h>
+#include <linux/regmap.h>
+#include <linux/workqueue.h>
+
+/* Offset of event and mask registers from status register. */
+#define MLXREG_HOTPLUG_EVENT_OFF	1
+#define MLXREG_HOTPLUG_MASK_OFF		2
+#define MLXREG_HOTPLUG_AGGR_MASK_OFF	1
+
+/* ASIC good health mask. */
+#define MLXREG_HOTPLUG_GOOD_HEALTH_MASK	0x02
+
+#define MLXREG_HOTPLUG_ATTRS_MAX	128
+#define MLXREG_HOTPLUG_NOT_ASSERT	3
+
+/**
+ * struct mlxreg_hotplug_priv_data - platform private data:
+ * @irq: platform device interrupt number;
+ * @dev: basic device;
+ * @pdev: platform device;
+ * @plat: platform data;
+ * @regmap: register map handle;
+ * @dwork_irq: delayed work template;
+ * @lock: spin lock;
+ * @hwmon: hwmon device;
+ * @mlxreg_hotplug_attr: sysfs attributes array;
+ * @mlxreg_hotplug_dev_attr: sysfs sensor device attribute array;
+ * @group: sysfs attribute group;
+ * @groups: list of sysfs attribute group for hwmon registration;
+ * @cell: location of top aggregation interrupt register;
+ * @mask: top aggregation interrupt common mask;
+ * @aggr_cache: last value of aggregation register status;
+ * @after_probe: flag indication probing completion;
+ * @not_asserted: number of entries in workqueue with no signal assertion;
+ */
+struct mlxreg_hotplug_priv_data {
+	int irq;
+	struct device *dev;
+	struct platform_device *pdev;
+	struct mlxreg_hotplug_platform_data *plat;
+	struct regmap *regmap;
+	struct delayed_work dwork_irq;
+	spinlock_t lock; /* sync with interrupt */
+	struct device *hwmon;
+	struct attribute *mlxreg_hotplug_attr[MLXREG_HOTPLUG_ATTRS_MAX + 1];
+	struct sensor_device_attribute_2
+			mlxreg_hotplug_dev_attr[MLXREG_HOTPLUG_ATTRS_MAX];
+	struct attribute_group group;
+	const struct attribute_group *groups[2];
+	u32 cell;
+	u32 mask;
+	u32 aggr_cache;
+	bool after_probe;
+	u8 not_asserted;
+};
+
+/* Environment variables array for udev. */
+static char *mlxreg_hotplug_udev_envp[] = { NULL, NULL };
+
+static int
+mlxreg_hotplug_udev_event_send(struct kobject *kobj,
+			       struct mlxreg_core_data *data, bool action)
+{
+	char event_str[MLXREG_CORE_LABEL_MAX_SIZE + 2];
+	char label[MLXREG_CORE_LABEL_MAX_SIZE] = { 0 };
+
+	mlxreg_hotplug_udev_envp[0] = event_str;
+	string_upper(label, data->label);
+	snprintf(event_str, MLXREG_CORE_LABEL_MAX_SIZE, "%s=%d", label, !!action);
+
+	return kobject_uevent_env(kobj, KOBJ_CHANGE, mlxreg_hotplug_udev_envp);
+}
+
+static void
+mlxreg_hotplug_pdata_export(void *pdata, void *regmap)
+{
+	struct mlxreg_core_hotplug_platform_data *dev_pdata = pdata;
+
+	/* Export regmap to underlying device. */
+	dev_pdata->regmap = regmap;
+}
+
+static int mlxreg_hotplug_device_create(struct mlxreg_hotplug_priv_data *priv,
+					struct mlxreg_core_data *data,
+					enum mlxreg_hotplug_kind kind)
+{
+	struct i2c_board_info *brdinfo = data->hpdev.brdinfo;
+	struct mlxreg_core_hotplug_platform_data *pdata;
+	struct i2c_client *client;
+
+	/* Notify user by sending hwmon uevent. */
+	mlxreg_hotplug_udev_event_send(&priv->hwmon->kobj, data, true);
+
+	/*
+	 * Return if adapter number is negative. It could be in case hotplug
+	 * event is not associated with hotplug device.
+	 */
+	if (data->hpdev.nr < 0 && data->hpdev.action != MLXREG_HOTPLUG_DEVICE_NO_ACTION)
+		return 0;
+
+	pdata = dev_get_platdata(&priv->pdev->dev);
+	switch (data->hpdev.action) {
+	case MLXREG_HOTPLUG_DEVICE_DEFAULT_ACTION:
+		data->hpdev.adapter = i2c_get_adapter(data->hpdev.nr +
+						      pdata->shift_nr);
+		if (!data->hpdev.adapter) {
+			dev_err(priv->dev, "Failed to get adapter for bus %d\n",
+				data->hpdev.nr + pdata->shift_nr);
+			return -EFAULT;
+		}
+
+		/* Export platform data to underlying device. */
+		if (brdinfo->platform_data)
+			mlxreg_hotplug_pdata_export(brdinfo->platform_data, pdata->regmap);
+
+		client = i2c_new_client_device(data->hpdev.adapter,
+					       brdinfo);
+		if (IS_ERR(client)) {
+			dev_err(priv->dev, "Failed to create client %s at bus %d at addr 0x%02x\n",
+				brdinfo->type, data->hpdev.nr +
+				pdata->shift_nr, brdinfo->addr);
+
+			i2c_put_adapter(data->hpdev.adapter);
+			data->hpdev.adapter = NULL;
+			return PTR_ERR(client);
+		}
+
+		data->hpdev.client = client;
+		break;
+	case MLXREG_HOTPLUG_DEVICE_PLATFORM_ACTION:
+		/* Export platform data to underlying device. */
+		if (data->hpdev.brdinfo && data->hpdev.brdinfo->platform_data)
+			mlxreg_hotplug_pdata_export(data->hpdev.brdinfo->platform_data,
+						    pdata->regmap);
+		/* Pass parent hotplug device handle to underlying device. */
+		data->notifier = data->hpdev.notifier;
+		data->hpdev.pdev = platform_device_register_resndata(&priv->pdev->dev,
+								     brdinfo->type,
+								     data->hpdev.nr,
+								     NULL, 0, data,
+								     sizeof(*data));
+		if (IS_ERR(data->hpdev.pdev))
+			return PTR_ERR(data->hpdev.pdev);
+
+		break;
+	default:
+		break;
+	}
+
+	if (data->hpdev.notifier && data->hpdev.notifier->user_handler)
+		return data->hpdev.notifier->user_handler(data->hpdev.notifier->handle, kind, 1);
+
+	return 0;
+}
+
+static void
+mlxreg_hotplug_device_destroy(struct mlxreg_hotplug_priv_data *priv,
+			      struct mlxreg_core_data *data,
+			      enum mlxreg_hotplug_kind kind)
+{
+	/* Notify user by sending hwmon uevent. */
+	mlxreg_hotplug_udev_event_send(&priv->hwmon->kobj, data, false);
+	if (data->hpdev.notifier && data->hpdev.notifier->user_handler)
+		data->hpdev.notifier->user_handler(data->hpdev.notifier->handle, kind, 0);
+
+	switch (data->hpdev.action) {
+	case MLXREG_HOTPLUG_DEVICE_DEFAULT_ACTION:
+		if (data->hpdev.client) {
+			i2c_unregister_device(data->hpdev.client);
+			data->hpdev.client = NULL;
+		}
+
+		if (data->hpdev.adapter) {
+			i2c_put_adapter(data->hpdev.adapter);
+			data->hpdev.adapter = NULL;
+		}
+		break;
+	case MLXREG_HOTPLUG_DEVICE_PLATFORM_ACTION:
+		if (data->hpdev.pdev)
+			platform_device_unregister(data->hpdev.pdev);
+		break;
+	default:
+		break;
+	}
+}
+
+static ssize_t mlxreg_hotplug_attr_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct mlxreg_hotplug_priv_data *priv = dev_get_drvdata(dev);
+	struct mlxreg_core_hotplug_platform_data *pdata;
+	int index = to_sensor_dev_attr_2(attr)->index;
+	int nr = to_sensor_dev_attr_2(attr)->nr;
+	struct mlxreg_core_item *item;
+	struct mlxreg_core_data *data;
+	u32 regval;
+	int ret;
+
+	pdata = dev_get_platdata(&priv->pdev->dev);
+	item = pdata->items + nr;
+	data = item->data + index;
+
+	ret = regmap_read(priv->regmap, data->reg, &regval);
+	if (ret)
+		return ret;
+
+	if (item->health) {
+		regval &= data->mask;
+	} else {
+		/* Bit = 0 : functional if item->inversed is true. */
+		if (item->inversed)
+			regval = !(regval & data->mask);
+		else
+			regval = !!(regval & data->mask);
+	}
+
+	return sprintf(buf, "%u\n", regval);
+}
+
+#define PRIV_ATTR(i) priv->mlxreg_hotplug_attr[i]
+#define PRIV_DEV_ATTR(i) priv->mlxreg_hotplug_dev_attr[i]
+
+static int mlxreg_hotplug_item_label_index_get(u32 mask, u32 bit)
+{
+	int i, j;
+
+	for (i = 0, j = -1; i <= bit; i++) {
+		if (mask & BIT(i))
+			j++;
+	}
+	return j;
+}
+
+static int mlxreg_hotplug_attr_init(struct mlxreg_hotplug_priv_data *priv)
+{
+	struct mlxreg_core_hotplug_platform_data *pdata;
+	struct mlxreg_core_item *item;
+	struct mlxreg_core_data *data;
+	unsigned long mask;
+	u32 regval;
+	int num_attrs = 0, id = 0, i, j, k, count, ret;
+
+	pdata = dev_get_platdata(&priv->pdev->dev);
+	item = pdata->items;
+
+	/* Go over all kinds of items - psu, pwr, fan. */
+	for (i = 0; i < pdata->counter; i++, item++) {
+		if (item->capability) {
+			/*
+			 * Read group capability register to get actual number
+			 * of interrupt capable components and set group mask
+			 * accordingly.
+			 */
+			ret = regmap_read(priv->regmap, item->capability,
+					  &regval);
+			if (ret)
+				return ret;
+
+			item->mask = GENMASK((regval & item->mask) - 1, 0);
+		}
+
+		data = item->data;
+
+		/* Go over all unmasked units within item. */
+		mask = item->mask;
+		k = 0;
+		count = item->ind ? item->ind : item->count;
+		for_each_set_bit(j, &mask, count) {
+			if (data->capability) {
+				/*
+				 * Read capability register and skip non
+				 * relevant attributes.
+				 */
+				ret = regmap_read(priv->regmap,
+						  data->capability, &regval);
+				if (ret)
+					return ret;
+
+				if (!(regval & data->bit)) {
+					data++;
+					continue;
+				}
+			}
+
+			PRIV_ATTR(id) = &PRIV_DEV_ATTR(id).dev_attr.attr;
+			PRIV_ATTR(id)->name = devm_kasprintf(&priv->pdev->dev,
+							     GFP_KERNEL,
+							     data->label);
+			if (!PRIV_ATTR(id)->name) {
+				dev_err(priv->dev, "Memory allocation failed for attr %d.\n",
+					id);
+				return -ENOMEM;
+			}
+
+			PRIV_DEV_ATTR(id).dev_attr.attr.name =
+							PRIV_ATTR(id)->name;
+			PRIV_DEV_ATTR(id).dev_attr.attr.mode = 0444;
+			PRIV_DEV_ATTR(id).dev_attr.show =
+						mlxreg_hotplug_attr_show;
+			PRIV_DEV_ATTR(id).nr = i;
+			PRIV_DEV_ATTR(id).index = k;
+			sysfs_attr_init(&PRIV_DEV_ATTR(id).dev_attr.attr);
+			data++;
+			id++;
+			k++;
+		}
+		num_attrs += k;
+	}
+
+	priv->group.attrs = devm_kcalloc(&priv->pdev->dev,
+					 num_attrs,
+					 sizeof(struct attribute *),
+					 GFP_KERNEL);
+	if (!priv->group.attrs)
+		return -ENOMEM;
+
+	priv->group.attrs = priv->mlxreg_hotplug_attr;
+	priv->groups[0] = &priv->group;
+	priv->groups[1] = NULL;
+
+	return 0;
+}
+
+static void
+mlxreg_hotplug_work_helper(struct mlxreg_hotplug_priv_data *priv,
+			   struct mlxreg_core_item *item)
+{
+	struct mlxreg_core_data *data;
+	unsigned long asserted;
+	u32 regval, bit;
+	int ret;
+
+	/*
+	 * Validate if item related to received signal type is valid.
+	 * It should never happen, excepted the situation when some
+	 * piece of hardware is broken. In such situation just produce
+	 * error message and return. Caller must continue to handle the
+	 * signals from other devices if any.
+	 */
+	if (unlikely(!item)) {
+		dev_err(priv->dev, "False signal: at offset:mask 0x%02x:0x%02x.\n",
+			item->reg, item->mask);
+
+		return;
+	}
+
+	/* Mask event. */
+	ret = regmap_write(priv->regmap, item->reg + MLXREG_HOTPLUG_MASK_OFF,
+			   0);
+	if (ret)
+		goto out;
+
+	/* Read status. */
+	ret = regmap_read(priv->regmap, item->reg, &regval);
+	if (ret)
+		goto out;
+
+	/* Set asserted bits and save last status. */
+	regval &= item->mask;
+	asserted = item->cache ^ regval;
+	item->cache = regval;
+	for_each_set_bit(bit, &asserted, 8) {
+		int pos;
+
+		pos = mlxreg_hotplug_item_label_index_get(item->mask, bit);
+		if (pos < 0)
+			goto out;
+
+		data = item->data + pos;
+		if (regval & BIT(bit)) {
+			if (item->inversed)
+				mlxreg_hotplug_device_destroy(priv, data, item->kind);
+			else
+				mlxreg_hotplug_device_create(priv, data, item->kind);
+		} else {
+			if (item->inversed)
+				mlxreg_hotplug_device_create(priv, data, item->kind);
+			else
+				mlxreg_hotplug_device_destroy(priv, data, item->kind);
+		}
+	}
+
+	/* Acknowledge event. */
+	ret = regmap_write(priv->regmap, item->reg + MLXREG_HOTPLUG_EVENT_OFF,
+			   0);
+	if (ret)
+		goto out;
+
+	/* Unmask event. */
+	ret = regmap_write(priv->regmap, item->reg + MLXREG_HOTPLUG_MASK_OFF,
+			   item->mask);
+
+ out:
+	if (ret)
+		dev_err(priv->dev, "Failed to complete workqueue.\n");
+}
+
+static void
+mlxreg_hotplug_health_work_helper(struct mlxreg_hotplug_priv_data *priv,
+				  struct mlxreg_core_item *item)
+{
+	struct mlxreg_core_data *data = item->data;
+	u32 regval;
+	int i, ret = 0;
+
+	for (i = 0; i < item->count; i++, data++) {
+		/* Mask event. */
+		ret = regmap_write(priv->regmap, data->reg +
+				   MLXREG_HOTPLUG_MASK_OFF, 0);
+		if (ret)
+			goto out;
+
+		/* Read status. */
+		ret = regmap_read(priv->regmap, data->reg, &regval);
+		if (ret)
+			goto out;
+
+		regval &= data->mask;
+
+		if (item->cache == regval)
+			goto ack_event;
+
+		/*
+		 * ASIC health indication is provided through two bits. Bits
+		 * value 0x2 indicates that ASIC reached the good health, value
+		 * 0x0 indicates ASIC the bad health or dormant state and value
+		 * 0x3 indicates the booting state. During ASIC reset it should
+		 * pass the following states: dormant -> booting -> good.
+		 */
+		if (regval == MLXREG_HOTPLUG_GOOD_HEALTH_MASK) {
+			if (!data->attached) {
+				/*
+				 * ASIC is in steady state. Connect associated
+				 * device, if configured.
+				 */
+				mlxreg_hotplug_device_create(priv, data, item->kind);
+				data->attached = true;
+			}
+		} else {
+			if (data->attached) {
+				/*
+				 * ASIC health is failed after ASIC has been
+				 * in steady state. Disconnect associated
+				 * device, if it has been connected.
+				 */
+				mlxreg_hotplug_device_destroy(priv, data, item->kind);
+				data->attached = false;
+				data->health_cntr = 0;
+			}
+		}
+		item->cache = regval;
+ack_event:
+		/* Acknowledge event. */
+		ret = regmap_write(priv->regmap, data->reg +
+				   MLXREG_HOTPLUG_EVENT_OFF, 0);
+		if (ret)
+			goto out;
+
+		/* Unmask event. */
+		ret = regmap_write(priv->regmap, data->reg +
+				   MLXREG_HOTPLUG_MASK_OFF, data->mask);
+		if (ret)
+			goto out;
+	}
+
+ out:
+	if (ret)
+		dev_err(priv->dev, "Failed to complete workqueue.\n");
+}
+
+/*
+ * mlxreg_hotplug_work_handler - performs traversing of device interrupt
+ * registers according to the below hierarchy schema:
+ *
+ *				Aggregation registers (status/mask)
+ * PSU registers:		*---*
+ * *-----------------*		|   |
+ * |status/event/mask|----->    | * |
+ * *-----------------*		|   |
+ * Power registers:		|   |
+ * *-----------------*		|   |
+ * |status/event/mask|----->    | * |
+ * *-----------------*		|   |
+ * FAN registers:		|   |--> CPU
+ * *-----------------*		|   |
+ * |status/event/mask|----->    | * |
+ * *-----------------*		|   |
+ * ASIC registers:		|   |
+ * *-----------------*		|   |
+ * |status/event/mask|----->    | * |
+ * *-----------------*		|   |
+ *				*---*
+ *
+ * In case some system changed are detected: FAN in/out, PSU in/out, power
+ * cable attached/detached, ASIC health good/bad, relevant device is created
+ * or destroyed.
+ */
+static void mlxreg_hotplug_work_handler(struct work_struct *work)
+{
+	struct mlxreg_core_hotplug_platform_data *pdata;
+	struct mlxreg_hotplug_priv_data *priv;
+	struct mlxreg_core_item *item;
+	u32 regval, aggr_asserted;
+	unsigned long flags;
+	int i, ret;
+
+	priv = container_of(work, struct mlxreg_hotplug_priv_data,
+			    dwork_irq.work);
+	pdata = dev_get_platdata(&priv->pdev->dev);
+	item = pdata->items;
+
+	/* Mask aggregation event. */
+	ret = regmap_write(priv->regmap, pdata->cell +
+			   MLXREG_HOTPLUG_AGGR_MASK_OFF, 0);
+	if (ret < 0)
+		goto out;
+
+	/* Read aggregation status. */
+	ret = regmap_read(priv->regmap, pdata->cell, &regval);
+	if (ret)
+		goto out;
+
+	regval &= pdata->mask;
+	aggr_asserted = priv->aggr_cache ^ regval;
+	priv->aggr_cache = regval;
+
+	/*
+	 * Handler is invoked, but no assertion is detected at top aggregation
+	 * status level. Set aggr_asserted to mask value to allow handler extra
+	 * run over all relevant signals to recover any missed signal.
+	 */
+	if (priv->not_asserted == MLXREG_HOTPLUG_NOT_ASSERT) {
+		priv->not_asserted = 0;
+		aggr_asserted = pdata->mask;
+	}
+	if (!aggr_asserted)
+		goto unmask_event;
+
+	/* Handle topology and health configuration changes. */
+	for (i = 0; i < pdata->counter; i++, item++) {
+		if (aggr_asserted & item->aggr_mask) {
+			if (item->health)
+				mlxreg_hotplug_health_work_helper(priv, item);
+			else
+				mlxreg_hotplug_work_helper(priv, item);
+		}
+	}
+
+	spin_lock_irqsave(&priv->lock, flags);
+
+	/*
+	 * It is possible, that some signals have been inserted, while
+	 * interrupt has been masked by mlxreg_hotplug_work_handler. In this
+	 * case such signals will be missed. In order to handle these signals
+	 * delayed work is canceled and work task re-scheduled for immediate
+	 * execution. It allows to handle missed signals, if any. In other case
+	 * work handler just validates that no new signals have been received
+	 * during masking.
+	 */
+	cancel_delayed_work(&priv->dwork_irq);
+	schedule_delayed_work(&priv->dwork_irq, 0);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	return;
+
+unmask_event:
+	priv->not_asserted++;
+	/* Unmask aggregation event (no need acknowledge). */
+	ret = regmap_write(priv->regmap, pdata->cell +
+			   MLXREG_HOTPLUG_AGGR_MASK_OFF, pdata->mask);
+
+ out:
+	if (ret)
+		dev_err(priv->dev, "Failed to complete workqueue.\n");
+}
+
+static int mlxreg_hotplug_set_irq(struct mlxreg_hotplug_priv_data *priv)
+{
+	struct mlxreg_core_hotplug_platform_data *pdata;
+	struct mlxreg_core_item *item;
+	struct mlxreg_core_data *data;
+	u32 regval;
+	int i, j, ret;
+
+	pdata = dev_get_platdata(&priv->pdev->dev);
+	item = pdata->items;
+
+	for (i = 0; i < pdata->counter; i++, item++) {
+		/* Clear group presense event. */
+		ret = regmap_write(priv->regmap, item->reg +
+				   MLXREG_HOTPLUG_EVENT_OFF, 0);
+		if (ret)
+			goto out;
+
+		/*
+		 * Verify if hardware configuration requires to disable
+		 * interrupt capability for some of components.
+		 */
+		data = item->data;
+		for (j = 0; j < item->count; j++, data++) {
+			/* Verify if the attribute has capability register. */
+			if (data->capability) {
+				/* Read capability register. */
+				ret = regmap_read(priv->regmap,
+						  data->capability, &regval);
+				if (ret)
+					goto out;
+
+				if (!(regval & data->bit))
+					item->mask &= ~BIT(j);
+			}
+		}
+
+		/* Set group initial status as mask and unmask group event. */
+		if (item->inversed) {
+			item->cache = item->mask;
+			ret = regmap_write(priv->regmap, item->reg +
+					   MLXREG_HOTPLUG_MASK_OFF,
+					   item->mask);
+			if (ret)
+				goto out;
+		}
+	}
+
+	/* Keep aggregation initial status as zero and unmask events. */
+	ret = regmap_write(priv->regmap, pdata->cell +
+			   MLXREG_HOTPLUG_AGGR_MASK_OFF, pdata->mask);
+	if (ret)
+		goto out;
+
+	/* Keep low aggregation initial status as zero and unmask events. */
+	if (pdata->cell_low) {
+		ret = regmap_write(priv->regmap, pdata->cell_low +
+				   MLXREG_HOTPLUG_AGGR_MASK_OFF,
+				   pdata->mask_low);
+		if (ret)
+			goto out;
+	}
+
+	/* Invoke work handler for initializing hot plug devices setting. */
+	mlxreg_hotplug_work_handler(&priv->dwork_irq.work);
+
+ out:
+	if (ret)
+		dev_err(priv->dev, "Failed to set interrupts.\n");
+	enable_irq(priv->irq);
+	return ret;
+}
+
+static void mlxreg_hotplug_unset_irq(struct mlxreg_hotplug_priv_data *priv)
+{
+	struct mlxreg_core_hotplug_platform_data *pdata;
+	struct mlxreg_core_item *item;
+	struct mlxreg_core_data *data;
+	int count, i, j;
+
+	pdata = dev_get_platdata(&priv->pdev->dev);
+	item = pdata->items;
+	disable_irq(priv->irq);
+	cancel_delayed_work_sync(&priv->dwork_irq);
+
+	/* Mask low aggregation event, if defined. */
+	if (pdata->cell_low)
+		regmap_write(priv->regmap, pdata->cell_low +
+			     MLXREG_HOTPLUG_AGGR_MASK_OFF, 0);
+
+	/* Mask aggregation event. */
+	regmap_write(priv->regmap, pdata->cell + MLXREG_HOTPLUG_AGGR_MASK_OFF,
+		     0);
+
+	/* Clear topology configurations. */
+	for (i = 0; i < pdata->counter; i++, item++) {
+		data = item->data;
+		/* Mask group presense event. */
+		regmap_write(priv->regmap, data->reg + MLXREG_HOTPLUG_MASK_OFF,
+			     0);
+		/* Clear group presense event. */
+		regmap_write(priv->regmap, data->reg +
+			     MLXREG_HOTPLUG_EVENT_OFF, 0);
+
+		/* Remove all the attached devices in group. */
+		count = item->count;
+		for (j = 0; j < count; j++, data++)
+			mlxreg_hotplug_device_destroy(priv, data, item->kind);
+	}
+}
+
+static irqreturn_t mlxreg_hotplug_irq_handler(int irq, void *dev)
+{
+	struct mlxreg_hotplug_priv_data *priv;
+
+	priv = (struct mlxreg_hotplug_priv_data *)dev;
+
+	/* Schedule work task for immediate execution.*/
+	schedule_delayed_work(&priv->dwork_irq, 0);
+
+	return IRQ_HANDLED;
+}
+
+static int mlxreg_hotplug_probe(struct platform_device *pdev)
+{
+	struct mlxreg_core_hotplug_platform_data *pdata;
+	struct mlxreg_hotplug_priv_data *priv;
+	struct i2c_adapter *deferred_adap;
+	int err;
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (!pdata) {
+		dev_err(&pdev->dev, "Failed to get platform data.\n");
+		return -EINVAL;
+	}
+
+	/* Defer probing if the necessary adapter is not configured yet. */
+	deferred_adap = i2c_get_adapter(pdata->deferred_nr);
+	if (!deferred_adap)
+		return -EPROBE_DEFER;
+	i2c_put_adapter(deferred_adap);
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	if (pdata->irq) {
+		priv->irq = pdata->irq;
+	} else {
+		priv->irq = platform_get_irq(pdev, 0);
+		if (priv->irq < 0)
+			return priv->irq;
+	}
+
+	priv->regmap = pdata->regmap;
+	priv->dev = pdev->dev.parent;
+	priv->pdev = pdev;
+
+	err = devm_request_irq(&pdev->dev, priv->irq,
+			       mlxreg_hotplug_irq_handler, IRQF_TRIGGER_FALLING
+			       | IRQF_SHARED, "mlxreg-hotplug", priv);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to request irq: %d\n", err);
+		return err;
+	}
+
+	disable_irq(priv->irq);
+	spin_lock_init(&priv->lock);
+	INIT_DELAYED_WORK(&priv->dwork_irq, mlxreg_hotplug_work_handler);
+	dev_set_drvdata(&pdev->dev, priv);
+
+	err = mlxreg_hotplug_attr_init(priv);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to allocate attributes: %d\n",
+			err);
+		return err;
+	}
+
+	priv->hwmon = devm_hwmon_device_register_with_groups(&pdev->dev,
+					"mlxreg_hotplug", priv, priv->groups);
+	if (IS_ERR(priv->hwmon)) {
+		dev_err(&pdev->dev, "Failed to register hwmon device %ld\n",
+			PTR_ERR(priv->hwmon));
+		return PTR_ERR(priv->hwmon);
+	}
+
+	/* Perform initial interrupts setup. */
+	mlxreg_hotplug_set_irq(priv);
+	priv->after_probe = true;
+
+	return 0;
+}
+
+static int mlxreg_hotplug_remove(struct platform_device *pdev)
+{
+	struct mlxreg_hotplug_priv_data *priv = dev_get_drvdata(&pdev->dev);
+
+	/* Clean interrupts setup. */
+	mlxreg_hotplug_unset_irq(priv);
+	devm_free_irq(&pdev->dev, priv->irq, priv);
+
+	return 0;
+}
+
+static struct platform_driver mlxreg_hotplug_driver = {
+	.driver = {
+		.name = "mlxreg-hotplug",
+	},
+	.probe = mlxreg_hotplug_probe,
+	.remove = mlxreg_hotplug_remove,
+};
+
+module_platform_driver(mlxreg_hotplug_driver);
+
+MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
+MODULE_DESCRIPTION("Mellanox regmap hotplug platform driver");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("platform:mlxreg-hotplug");