platform/mellanox: mlxreg-hotplug: Add hotplug hwmon uevent notification

Notify user when hotplug device signal is received in order to allow user
to handle such case, if it wishes to take some action on this matter.

Signed-off-by: Vadim Pasternak <[e-mail]>
Signed-off-by: Darren Hart (VMware) <[e-mail]>

drivers/platform/mellanox/mlxreg-hotplug.c

···
 {
 	struct mlxreg_core_hotplug_platform_data *pdata;
 
+	/* Notify user by sending hwmon uevent. */
+	kobject_uevent(&priv->hwmon->kobj, KOBJ_CHANGE);
+
 	/*
 	 * Return if adapter number is negative. It could be in case hotplug
 	 * event is not associated with hotplug device.
···
 	return 0;
 }
 
-static void mlxreg_hotplug_device_destroy(struct mlxreg_core_data *data)
+static void
+mlxreg_hotplug_device_destroy(struct mlxreg_hotplug_priv_data *priv,
+			      struct mlxreg_core_data *data)
 {
+	/* Notify user by sending hwmon uevent. */
+	kobject_uevent(&priv->hwmon->kobj, KOBJ_CHANGE);
+
 	if (data->hpdev.client) {
 		i2c_unregister_device(data->hpdev.client);
 		data->hpdev.client = NULL;
···
 		data = item->data + bit;
 		if (regval & BIT(bit)) {
 			if (item->inversed)
-				mlxreg_hotplug_device_destroy(data);
+				mlxreg_hotplug_device_destroy(priv, data);
 			else
 				mlxreg_hotplug_device_create(priv, data);
 		} else {
 			if (item->inversed)
 				mlxreg_hotplug_device_create(priv, data);
 			else
-				mlxreg_hotplug_device_destroy(data);
+				mlxreg_hotplug_device_destroy(priv, data);
 		}
 	}
 
···
 				 * in steady state. Disconnect associated
 				 * device, if it has been connected.
 				 */
-				mlxreg_hotplug_device_destroy(data);
+				mlxreg_hotplug_device_destroy(priv, data);
 				data->attached = false;
 				data->health_cntr = 0;
 			}
···
 		/* Remove all the attached devices in group. */
 		count = item->count;
 		for (j = 0; j < count; j++, data++)
-			mlxreg_hotplug_device_destroy(data);
+			mlxreg_hotplug_device_destroy(priv, data);
 	}
 }
 
···
 	disable_irq(priv->irq);
 	spin_lock_init(&priv->lock);
 	INIT_DELAYED_WORK(&priv->dwork_irq, mlxreg_hotplug_work_handler);
-	/* Perform initial interrupts setup. */
-	mlxreg_hotplug_set_irq(priv);
-
-	priv->after_probe = true;
 	dev_set_drvdata(&pdev->dev, priv);
 
 	err = mlxreg_hotplug_attr_init(priv);
···
 			PTR_ERR(priv->hwmon));
 		return PTR_ERR(priv->hwmon);
 	}
+
+	/* Perform initial interrupts setup. */
+	mlxreg_hotplug_set_irq(priv);
+	priv->after_probe = true;
 
 	return 0;
 }