HID: sensors: introduce sensor framework

Adding processing for HID Sensor usage table as defined by
HID 1.12, Request #: HUTRR39, dated 05 May, 2011.
This driver uses HID driver framework to register, send and
receive events.
This uses MFD framework, so that actual processing for a
specific usage id can be done in a different driver. For
example an accelerometer driver can be a separate driver and
use the interface provided by this driver to register for
events.

Signed-off-by: srinivas pandruvada <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/hid/Kconfig

···
 	---help---
 	Support for Zydacron remote control.
 
+config HID_SENSOR_HUB
+	tristate "HID Sensors framework support"
+	depends on USB_HID
+	select MFD_CORE
+	default n
+	-- help---
+	  Support for HID Sensor framework. This creates a MFD instance
+	  for a sensor hub and identifies all the sensors connected to it.
+	  Each sensor is registered as a MFD cell, so that sensor specific
+	  processing can be done in a separate driver. Each sensor
+	  drivers can use the service provided by this driver to register
+	  for events and handle data streams. Each sensor driver can format
+	  data and present to user mode using input or IIO interface.
+
 endmenu
 
 endif # HID

drivers/hid/Makefile

···
 obj-$(CONFIG_HID_WACOM)		+= hid-wacom.o
 obj-$(CONFIG_HID_WALTOP)	+= hid-waltop.o
 obj-$(CONFIG_HID_WIIMOTE)	+= hid-wiimote.o
+obj-$(CONFIG_HID_SENSOR_HUB)	+= hid-sensor-hub.o
 
 obj-$(CONFIG_USB_HID)		+= usbhid/
 obj-$(CONFIG_USB_MOUSE)		+= usbhid/

drivers/hid/hid-sensor-hub.c

···
+/*
+ * HID Sensors Driver
+ * Copyright (c) 2012, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+#include <linux/device.h>
+#include <linux/hid.h>
+#include <linux/usb.h>
+#include "usbhid/usbhid.h"
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/mfd/core.h>
+#include <linux/list.h>
+#include <linux/hid-sensor-ids.h>
+#include <linux/hid-sensor-hub.h>
+#include "hid-ids.h"
+
+/**
+ * struct sensor_hub_pending - Synchronous read pending information
+ * @status:		Pending status true/false.
+ * @ready:		Completion synchronization data.
+ * @usage_id:		Usage id for physical device, E.g. Gyro usage id.
+ * @attr_usage_id:	Usage Id of a field, E.g. X-AXIS for a gyro.
+ * @raw_size:		Response size for a read request.
+ * @raw_data:		Place holder for received response.
+ */
+struct sensor_hub_pending {
+	bool status;
+	struct completion ready;
+	u32 usage_id;
+	u32 attr_usage_id;
+	int raw_size;
+	u8  *raw_data;
+};
+
+/**
+ * struct sensor_hub_data - Hold a instance data for a HID hub device
+ * @hsdev:		Stored hid instance for current hub device.
+ * @mutex:		Mutex to serialize synchronous request.
+ * @lock:		Spin lock to protect pending request structure.
+ * @pending:		Holds information of pending sync read request.
+ * @dyn_callback_list:	Holds callback function
+ * @dyn_callback_lock:	spin lock to protect callback list
+ * @hid_sensor_hub_client_devs:	Stores all MFD cells for a hub instance.
+ * @hid_sensor_client_cnt: Number of MFD cells, (no of sensors attached).
+ */
+struct sensor_hub_data {
+	struct hid_sensor_hub_device *hsdev;
+	struct mutex mutex;
+	spinlock_t lock;
+	struct sensor_hub_pending pending;
+	struct list_head dyn_callback_list;
+	spinlock_t dyn_callback_lock;
+	struct mfd_cell *hid_sensor_hub_client_devs;
+	int hid_sensor_client_cnt;
+};
+
+/**
+ * struct hid_sensor_hub_callbacks_list - Stores callback list
+ * @list:		list head.
+ * @usage_id:		usage id for a physical device.
+ * @usage_callback:	Stores registered callback functions.
+ * @priv:		Private data for a physical device.
+ */
+struct hid_sensor_hub_callbacks_list {
+	struct list_head list;
+	u32 usage_id;
+	struct hid_sensor_hub_callbacks *usage_callback;
+	void *priv;
+};
+
+static int sensor_hub_check_for_sensor_page(struct hid_device *hdev)
+{
+	int i;
+	int ret = -EINVAL;
+
+	for (i = 0; i < hdev->maxcollection; i++) {
+		struct hid_collection *col = &hdev->collection[i];
+		if (col->type == HID_COLLECTION_PHYSICAL &&
+		   (col->usage & HID_USAGE_PAGE) == HID_UP_SENSOR) {
+			ret = 0;
+			break;
+		}
+	}
+
+	return ret;
+}
+
+static struct hid_report *sensor_hub_report(int id, struct hid_device *hdev,
+						int dir)
+{
+	struct hid_report *report;
+
+	list_for_each_entry(report, &hdev->report_enum[dir].report_list, list) {
+		if (report->id == id)
+			return report;
+	}
+	hid_warn(hdev, "No report with id 0x%x found\n", id);
+
+	return NULL;
+}
+
+static int sensor_hub_get_physical_device_count(
+				struct hid_report_enum *report_enum)
+{
+	struct hid_report *report;
+	struct hid_field *field;
+	int cnt = 0;
+
+	list_for_each_entry(report, &report_enum->report_list, list) {
+		field = report->field[0];
+		if (report->maxfield && field &&
+					field->physical)
+			cnt++;
+	}
+
+	return cnt;
+}
+
+static void sensor_hub_fill_attr_info(
+		struct hid_sensor_hub_attribute_info *info,
+		s32 index, s32 report_id, s32 units, s32 unit_expo, s32 size)
+{
+	info->index = index;
+	info->report_id = report_id;
+	info->units = units;
+	info->unit_expo = unit_expo;
+	info->size = size/8;
+}
+
+static struct hid_sensor_hub_callbacks *sensor_hub_get_callback(
+					struct hid_device *hdev,
+					u32 usage_id, void **priv)
+{
+	struct hid_sensor_hub_callbacks_list *callback;
+	struct sensor_hub_data *pdata = hid_get_drvdata(hdev);
+
+	spin_lock(&pdata->dyn_callback_lock);
+	list_for_each_entry(callback, &pdata->dyn_callback_list, list)
+		if (callback->usage_id == usage_id) {
+			*priv = callback->priv;
+			spin_unlock(&pdata->dyn_callback_lock);
+			return callback->usage_callback;
+		}
+	spin_unlock(&pdata->dyn_callback_lock);
+
+	return NULL;
+}
+
+int sensor_hub_register_callback(struct hid_sensor_hub_device *hsdev,
+			u32 usage_id,
+			struct hid_sensor_hub_callbacks *usage_callback)
+{
+	struct hid_sensor_hub_callbacks_list *callback;
+	struct sensor_hub_data *pdata = hid_get_drvdata(hsdev->hdev);
+
+	spin_lock(&pdata->dyn_callback_lock);
+	list_for_each_entry(callback, &pdata->dyn_callback_list, list)
+		if (callback->usage_id == usage_id) {
+			spin_unlock(&pdata->dyn_callback_lock);
+			return -EINVAL;
+		}
+	callback = kzalloc(sizeof(*callback), GFP_KERNEL);
+	if (!callback) {
+		spin_unlock(&pdata->dyn_callback_lock);
+		return -ENOMEM;
+	}
+	callback->usage_callback = usage_callback;
+	callback->usage_id = usage_id;
+	callback->priv = NULL;
+	list_add_tail(&callback->list, &pdata->dyn_callback_list);
+	spin_unlock(&pdata->dyn_callback_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sensor_hub_register_callback);
+
+int sensor_hub_remove_callback(struct hid_sensor_hub_device *hsdev,
+				u32 usage_id)
+{
+	struct hid_sensor_hub_callbacks_list *callback;
+	struct sensor_hub_data *pdata = hid_get_drvdata(hsdev->hdev);
+
+	spin_lock(&pdata->dyn_callback_lock);
+	list_for_each_entry(callback, &pdata->dyn_callback_list, list)
+		if (callback->usage_id == usage_id) {
+			list_del(&callback->list);
+			kfree(callback);
+			break;
+		}
+	spin_unlock(&pdata->dyn_callback_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sensor_hub_remove_callback);
+
+int sensor_hub_set_feature(struct hid_sensor_hub_device *hsdev, u32 report_id,
+				u32 field_index, s32 value)
+{
+	struct hid_report *report;
+	struct sensor_hub_data *data =  hid_get_drvdata(hsdev->hdev);
+	int ret = 0;
+
+	if (report_id < 0)
+		return -EINVAL;
+
+	mutex_lock(&data->mutex);
+	report = sensor_hub_report(report_id, hsdev->hdev, HID_FEATURE_REPORT);
+	if (!report || (field_index >=  report->maxfield)) {
+		ret = -EINVAL;
+		goto done_proc;
+	}
+	hid_set_field(report->field[field_index], 0, value);
+	usbhid_submit_report(hsdev->hdev, report, USB_DIR_OUT);
+	usbhid_wait_io(hsdev->hdev);
+
+done_proc:
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sensor_hub_set_feature);
+
+int sensor_hub_get_feature(struct hid_sensor_hub_device *hsdev, u32 report_id,
+				u32 field_index, s32 *value)
+{
+	struct hid_report *report;
+	struct sensor_hub_data *data =  hid_get_drvdata(hsdev->hdev);
+	int ret = 0;
+
+	if (report_id < 0)
+		return -EINVAL;
+
+	mutex_lock(&data->mutex);
+	report = sensor_hub_report(report_id, hsdev->hdev, HID_FEATURE_REPORT);
+	if (!report || (field_index >=  report->maxfield)) {
+		ret = -EINVAL;
+		goto done_proc;
+	}
+	usbhid_submit_report(hsdev->hdev, report, USB_DIR_IN);
+	usbhid_wait_io(hsdev->hdev);
+	*value = report->field[field_index]->value[0];
+
+done_proc:
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sensor_hub_get_feature);
+
+
+int sensor_hub_input_attr_get_raw_value(struct hid_sensor_hub_device *hsdev,
+					u32 usage_id,
+					u32 attr_usage_id, u32 report_id)
+{
+	struct sensor_hub_data *data =  hid_get_drvdata(hsdev->hdev);
+	unsigned long flags;
+	struct hid_report *report;
+	int ret_val = 0;
+
+	if (report_id < 0)
+		return -EINVAL;
+
+	mutex_lock(&data->mutex);
+	memset(&data->pending, 0, sizeof(data->pending));
+	init_completion(&data->pending.ready);
+	data->pending.usage_id = usage_id;
+	data->pending.attr_usage_id = attr_usage_id;
+	data->pending.raw_size = 0;
+
+	spin_lock_irqsave(&data->lock, flags);
+	data->pending.status = true;
+	report = sensor_hub_report(report_id, hsdev->hdev, HID_INPUT_REPORT);
+	if (!report) {
+		spin_unlock_irqrestore(&data->lock, flags);
+		goto err_free;
+	}
+	usbhid_submit_report(hsdev->hdev, report, USB_DIR_IN);
+	spin_unlock_irqrestore(&data->lock, flags);
+	wait_for_completion_interruptible_timeout(&data->pending.ready, HZ*5);
+	switch (data->pending.raw_size) {
+	case 1:
+		ret_val = *(u8 *)data->pending.raw_data;
+		break;
+	case 2:
+		ret_val = *(u16 *)data->pending.raw_data;
+		break;
+	case 4:
+		ret_val = *(u32 *)data->pending.raw_data;
+		break;
+	default:
+		ret_val = 0;
+	}
+	kfree(data->pending.raw_data);
+
+err_free:
+	data->pending.status = false;
+	mutex_unlock(&data->mutex);
+
+	return ret_val;
+}
+EXPORT_SYMBOL_GPL(sensor_hub_input_attr_get_raw_value);
+
+int sensor_hub_input_get_attribute_info(struct hid_sensor_hub_device *hsdev,
+				u8 type,
+				u32 usage_id,
+				u32 attr_usage_id,
+				struct hid_sensor_hub_attribute_info *info)
+{
+	int ret = -1;
+	int i, j;
+	int collection_index = -1;
+	struct hid_report *report;
+	struct hid_field *field;
+	struct hid_report_enum *report_enum;
+	struct hid_device *hdev = hsdev->hdev;
+
+	/* Initialize with defaults */
+	info->usage_id = usage_id;
+	info->attrib_id =  attr_usage_id;
+	info->report_id = -1;
+	info->index = -1;
+	info->units = -1;
+	info->unit_expo = -1;
+
+	for (i = 0; i < hdev->maxcollection; ++i) {
+		struct hid_collection *collection = &hdev->collection[i];
+		if (usage_id == collection->usage) {
+			collection_index = i;
+			break;
+		}
+	}
+	if (collection_index == -1)
+		goto err_ret;
+
+	report_enum = &hdev->report_enum[type];
+	list_for_each_entry(report, &report_enum->report_list, list) {
+		for (i = 0; i < report->maxfield; ++i) {
+			field = report->field[i];
+			if (field->physical == usage_id &&
+				field->logical == attr_usage_id) {
+				sensor_hub_fill_attr_info(info, i, report->id,
+					field->unit, field->unit_exponent,
+					field->report_size);
+				ret = 0;
+			} else {
+				for (j = 0; j < field->maxusage; ++j) {
+					if (field->usage[j].hid ==
+					attr_usage_id &&
+					field->usage[j].collection_index ==
+					collection_index)  {
+						sensor_hub_fill_attr_info(info,
+							i, report->id,
+							field->unit,
+							field->unit_exponent,
+							field->report_size);
+						ret = 0;
+						break;
+					}
+				}
+			}
+			if (ret == 0)
+				break;
+		}
+	}
+
+err_ret:
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sensor_hub_input_get_attribute_info);
+
+#ifdef CONFIG_PM
+static int sensor_hub_suspend(struct hid_device *hdev, pm_message_t message)
+{
+	struct sensor_hub_data *pdata =  hid_get_drvdata(hdev);
+	struct hid_sensor_hub_callbacks_list *callback;
+
+	hid_dbg(hdev, " sensor_hub_suspend\n");
+	spin_lock(&pdata->dyn_callback_lock);
+	list_for_each_entry(callback, &pdata->dyn_callback_list, list) {
+		if (callback->usage_callback->suspend)
+			callback->usage_callback->suspend(
+					pdata->hsdev, callback->priv);
+	}
+	spin_unlock(&pdata->dyn_callback_lock);
+
+	return 0;
+}
+
+static int sensor_hub_resume(struct hid_device *hdev)
+{
+	struct sensor_hub_data *pdata =  hid_get_drvdata(hdev);
+	struct hid_sensor_hub_callbacks_list *callback;
+
+	hid_dbg(hdev, " sensor_hub_resume\n");
+	spin_lock(&pdata->dyn_callback_lock);
+	list_for_each_entry(callback, &pdata->dyn_callback_list, list) {
+		if (callback->usage_callback->resume)
+			callback->usage_callback->resume(
+					pdata->hsdev, callback->priv);
+	}
+	spin_unlock(&pdata->dyn_callback_lock);
+
+	return 0;
+}
+
+static int sensor_hub_reset_resume(struct hid_device *hdev)
+{
+	return 0;
+}
+#endif
+/*
+ * Handle raw report as sent by device
+ */
+static int sensor_hub_raw_event(struct hid_device *hdev,
+		struct hid_report *report, u8 *raw_data, int size)
+{
+	int i;
+	u8 *ptr;
+	int sz;
+	struct sensor_hub_data *pdata = hid_get_drvdata(hdev);
+	unsigned long flags;
+	struct hid_sensor_hub_callbacks *callback = NULL;
+	struct hid_collection *collection = NULL;
+	void *priv = NULL;
+
+	hid_dbg(hdev, "sensor_hub_raw_event report id:0x%x size:%d type:%d\n",
+			 report->id, size, report->type);
+	hid_dbg(hdev, "maxfield:%d\n", report->maxfield);
+	if (report->type != HID_INPUT_REPORT)
+		return 1;
+
+	ptr = raw_data;
+	ptr++; /*Skip report id*/
+
+	if (!report)
+		goto err_report;
+
+	spin_lock_irqsave(&pdata->lock, flags);
+
+	for (i = 0; i < report->maxfield; ++i) {
+
+		hid_dbg(hdev, "%d collection_index:%x hid:%x sz:%x\n",
+				i, report->field[i]->usage->collection_index,
+				report->field[i]->usage->hid,
+				report->field[i]->report_size/8);
+
+		sz = report->field[i]->report_size/8;
+		if (pdata->pending.status && pdata->pending.attr_usage_id ==
+				report->field[i]->usage->hid) {
+			hid_dbg(hdev, "data was pending ...\n");
+			pdata->pending.raw_data = kmalloc(sz, GFP_KERNEL);
+			if (pdata->pending.raw_data) {
+				memcpy(pdata->pending.raw_data, ptr, sz);
+				pdata->pending.raw_size  = sz;
+			} else
+				pdata->pending.raw_size = 0;
+			complete(&pdata->pending.ready);
+		}
+		collection = &hdev->collection[
+				report->field[i]->usage->collection_index];
+		hid_dbg(hdev, "collection->usage %x\n",
+					collection->usage);
+		callback = sensor_hub_get_callback(pdata->hsdev->hdev,
+						report->field[i]->physical,
+							&priv);
+		if (callback && callback->capture_sample) {
+			if (report->field[i]->logical)
+				callback->capture_sample(pdata->hsdev,
+					report->field[i]->logical, sz, ptr,
+					callback->pdev);
+			else
+				callback->capture_sample(pdata->hsdev,
+					report->field[i]->usage->hid, sz, ptr,
+					callback->pdev);
+		}
+		ptr += sz;
+	}
+	if (callback && collection && callback->send_event)
+		callback->send_event(pdata->hsdev, collection->usage,
+				callback->pdev);
+	spin_unlock_irqrestore(&pdata->lock, flags);
+
+err_report:
+	return 1;
+}
+
+static int sensor_hub_probe(struct hid_device *hdev,
+				const struct hid_device_id *id)
+{
+	int ret;
+	struct sensor_hub_data *sd;
+	int i;
+	char *name;
+	struct hid_report *report;
+	struct hid_report_enum *report_enum;
+	struct hid_field *field;
+	int dev_cnt;
+
+	sd = kzalloc(sizeof(struct sensor_hub_data), GFP_KERNEL);
+	if (!sd) {
+		hid_err(hdev, "cannot allocate Sensor data\n");
+		return -ENOMEM;
+	}
+	sd->hsdev = kzalloc(sizeof(struct hid_sensor_hub_device), GFP_KERNEL);
+	if (!sd->hsdev) {
+		hid_err(hdev, "cannot allocate hid_sensor_hub_device\n");
+		ret = -ENOMEM;
+		goto err_free_hub;
+	}
+	hid_set_drvdata(hdev, sd);
+	sd->hsdev->hdev = hdev;
+	sd->hsdev->vendor_id = hdev->vendor;
+	sd->hsdev->product_id = hdev->product;
+	spin_lock_init(&sd->lock);
+	spin_lock_init(&sd->dyn_callback_lock);
+	mutex_init(&sd->mutex);
+	ret = hid_parse(hdev);
+	if (ret) {
+		hid_err(hdev, "parse failed\n");
+		goto err_free;
+	}
+	if (sensor_hub_check_for_sensor_page(hdev) < 0) {
+		hid_err(hdev, "sensor page not found\n");
+		goto err_free;
+	}
+	INIT_LIST_HEAD(&hdev->inputs);
+
+	hdev->claimed = HID_CLAIMED_INPUT;
+	ret = hid_hw_start(hdev, 0);
+	if (ret) {
+		hid_err(hdev, "hw start failed\n");
+		goto err_free;
+	}
+	ret = hid_hw_open(hdev);
+	if (ret) {
+		hid_err(hdev, "failed to open input interrupt pipe\n");
+		goto err_stop_hw;
+	}
+
+	INIT_LIST_HEAD(&sd->dyn_callback_list);
+	sd->hid_sensor_client_cnt = 0;
+	report_enum = &hdev->report_enum[HID_INPUT_REPORT];
+
+	dev_cnt = sensor_hub_get_physical_device_count(report_enum);
+	if (dev_cnt > HID_MAX_PHY_DEVICES) {
+		hid_err(hdev, "Invalid Physical device count\n");
+		ret = -EINVAL;
+		goto err_close;
+	}
+	sd->hid_sensor_hub_client_devs = kzalloc(dev_cnt *
+						sizeof(struct mfd_cell),
+						GFP_KERNEL);
+	if (sd->hid_sensor_hub_client_devs == NULL) {
+		hid_err(hdev,
+			"Failed to allocate memory for mfd cells\n");
+			ret = -ENOMEM;
+			goto err_close;
+	}
+	list_for_each_entry(report, &report_enum->report_list, list) {
+		hid_dbg(hdev, "Report id:%x\n", report->id);
+		field = report->field[0];
+		if (report->maxfield && field &&
+					field->physical) {
+			name = kasprintf(GFP_KERNEL, "HID-SENSOR-%x",
+						field->physical);
+			if (name  == NULL) {
+				hid_err(hdev,
+					"Failed MFD device name\n");
+					ret = -ENOMEM;
+					goto err_free_cells;
+			}
+			sd->hid_sensor_hub_client_devs[
+				sd->hid_sensor_client_cnt].name = name;
+			sd->hid_sensor_hub_client_devs[
+				sd->hid_sensor_client_cnt].platform_data =
+						sd->hsdev;
+			sd->hid_sensor_hub_client_devs[
+				sd->hid_sensor_client_cnt].pdata_size =
+						sizeof(*sd->hsdev);
+			hid_dbg(hdev, "Adding %s:%p\n", name, sd);
+			sd->hid_sensor_client_cnt++;
+		}
+	}
+	ret = mfd_add_devices(&hdev->dev, 0, sd->hid_sensor_hub_client_devs,
+		sd->hid_sensor_client_cnt, NULL, 0);
+	if (ret < 0)
+		goto err_free_names;
+
+	return ret;
+
+err_free_names:
+	for (i = 0; i < sd->hid_sensor_client_cnt ; ++i)
+		kfree(sd->hid_sensor_hub_client_devs[i].name);
+err_free_cells:
+	kfree(sd->hid_sensor_hub_client_devs);
+err_close:
+	hid_hw_stop(hdev);
+	hid_hw_close(hdev);
+err_stop_hw:
+	hid_hw_stop(hdev);
+err_free:
+	kfree(sd->hsdev);
+err_free_hub:
+	kfree(sd);
+
+	return ret;
+}
+
+static void sensor_hub_remove(struct hid_device *hdev)
+{
+	struct sensor_hub_data *data = hid_get_drvdata(hdev);
+	unsigned long flags;
+	int i;
+
+	hid_dbg(hdev, " hardware removed\n");
+	hdev->claimed &= ~HID_CLAIMED_INPUT;
+	hid_hw_stop(hdev);
+	hid_hw_close(hdev);
+	spin_lock_irqsave(&data->lock, flags);
+	if (data->pending.status)
+		complete(&data->pending.ready);
+	spin_unlock_irqrestore(&data->lock, flags);
+	mfd_remove_devices(&hdev->dev);
+	for (i = 0; i < data->hid_sensor_client_cnt ; ++i)
+		kfree(data->hid_sensor_hub_client_devs[i].name);
+	kfree(data->hid_sensor_hub_client_devs);
+	hid_set_drvdata(hdev, NULL);
+	mutex_destroy(&data->mutex);
+	kfree(data->hsdev);
+	kfree(data);
+}
+
+static const struct hid_device_id sensor_hub_devices[] = {
+	{ HID_USB_DEVICE(USB_VENDOR_ID_INTEL_8086,
+			USB_DEVICE_ID_SENSOR_HUB_1020) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_INTEL_8087,
+			USB_DEVICE_ID_SENSOR_HUB_1020) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_INTEL_8086,
+			USB_DEVICE_ID_SENSOR_HUB_09FA) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_INTEL_8087,
+			USB_DEVICE_ID_SENSOR_HUB_09FA) },
+	{ HID_USB_DEVICE(USB_VENDOR_ID_STANTUM_STM,
+			USB_DEVICE_ID_SENSOR_HUB_7014) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, sensor_hub_devices);
+
+static const struct hid_usage_id sensor_hub_grabbed_usages[] = {
+	{ HID_ANY_ID, HID_ANY_ID, HID_ANY_ID },
+	{ HID_ANY_ID - 1, HID_ANY_ID - 1, HID_ANY_ID - 1 }
+};
+
+static struct hid_driver sensor_hub_driver = {
+	.name = "hid-sensor-hub",
+	.id_table = sensor_hub_devices,
+	.probe = sensor_hub_probe,
+	.remove = sensor_hub_remove,
+	.raw_event = sensor_hub_raw_event,
+#ifdef CONFIG_PM
+	.suspend = sensor_hub_suspend,
+	.resume =  sensor_hub_resume,
+	.reset_resume =  sensor_hub_reset_resume,
+#endif
+};
+
+static int __init sensor_hub_init(void)
+{
+	return hid_register_driver(&sensor_hub_driver);
+}
+
+static void __exit sensor_hub_exit(void)
+{
+	hid_unregister_driver(&sensor_hub_driver);
+}
+
+module_init(sensor_hub_init);
+module_exit(sensor_hub_exit);
+
+MODULE_DESCRIPTION("HID Sensor Hub driver");
+MODULE_AUTHOR("Srinivas Pandruvada <[e-mail]>");
+MODULE_LICENSE("GPL");

include/linux/hid-sensor-hub.h

···
+/*
+ * HID Sensors Driver
+ * Copyright (c) 2012, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+#ifndef _HID_SENSORS_HUB_H
+#define _HID_SENSORS_HUB_H
+
+#include <linux/hid.h>
+#include <linux/hid-sensor-ids.h>
+
+/**
+ * struct hid_sensor_hub_attribute_info - Attribute info
+ * @usage_id:		Parent usage id of a physical device.
+ * @attrib_id:		Attribute id for this attribute.
+ * @report_id:		Report id in which this information resides.
+ * @index:		Field index in the report.
+ * @units:		Measurment unit for this attribute.
+ * @unit_expo:		Exponent used in the data.
+ * @size:		Size in bytes for data size.
+ */
+struct hid_sensor_hub_attribute_info {
+	u32 usage_id;
+	u32 attrib_id;
+	s32 report_id;
+	s32 index;
+	s32 units;
+	s32 unit_expo;
+	s32 size;
+};
+
+/**
+ * struct hid_sensor_hub_device - Stores the hub instance data
+ * @hdev:		Stores the hid instance.
+ * @vendor_id:		Vendor id of hub device.
+ * @product_id:		Product id of hub device.
+ */
+struct hid_sensor_hub_device {
+	struct hid_device *hdev;
+	u32 vendor_id;
+	u32 product_id;
+};
+
+/**
+ * struct hid_sensor_hub_callbacks - Client callback functions
+ * @pdev:		Platform device instance of the client driver.
+ * @suspend:		Suspend callback.
+ * @resume:		Resume callback.
+ * @capture_sample:	Callback to get a sample.
+ * @send_event:		Send notification to indicate all samples are
+ *			captured, process and send event
+ */
+struct hid_sensor_hub_callbacks {
+	struct platform_device *pdev;
+	int (*suspend)(struct hid_sensor_hub_device *hsdev, void *priv);
+	int (*resume)(struct hid_sensor_hub_device *hsdev, void *priv);
+	int (*capture_sample)(struct hid_sensor_hub_device *hsdev,
+			u32 usage_id, size_t raw_len, char *raw_data,
+			void *priv);
+	int (*send_event)(struct hid_sensor_hub_device *hsdev, u32 usage_id,
+			 void *priv);
+};
+
+/* Registration functions */
+
+/**
+* sensor_hub_register_callback() - Register client callbacks
+* @hsdev:	Hub device instance.
+* @usage_id:	Usage id of the client (E.g. 0x200076 for Gyro).
+* @usage_callback: Callback function storage
+*
+* Used to register callbacks by client processing drivers. Sensor
+* hub core driver will call these callbacks to offload processing
+* of data streams and notifications.
+*/
+int sensor_hub_register_callback(struct hid_sensor_hub_device *hsdev,
+			u32 usage_id,
+			struct hid_sensor_hub_callbacks *usage_callback);
+
+/**
+* sensor_hub_remove_callback() - Remove client callbacks
+* @hsdev:	Hub device instance.
+* @usage_id:	Usage id of the client (E.g. 0x200076 for Gyro).
+*
+* If there is a callback registred, this call will remove that
+* callbacks, so that it will stop data and event notifications.
+*/
+int sensor_hub_remove_callback(struct hid_sensor_hub_device *hsdev,
+			u32 usage_id);
+
+
+/* Hid sensor hub core interfaces */
+
+/**
+* sensor_hub_input_get_attribute_info() - Get an attribute information
+* @hsdev:	Hub device instance.
+* @type:	Type of this attribute, input/output/feature
+* @usage_id:	Attribute usage id of parent physical device as per spec
+* @attr_usage_id:	Attribute usage id as per spec
+* @info:	return information about attribute after parsing report
+*
+* Parses report and returns the attribute information such as report id,
+* field index, units and exponet etc.
+*/
+int sensor_hub_input_get_attribute_info(struct hid_sensor_hub_device *hsdev,
+			u8 type,
+			u32 usage_id, u32 attr_usage_id,
+			struct hid_sensor_hub_attribute_info *info);
+
+/**
+* sensor_hub_input_attr_get_raw_value() - Synchronous read request
+* @usage_id:	Attribute usage id of parent physical device as per spec
+* @attr_usage_id:	Attribute usage id as per spec
+* @report_id:	Report id to look for
+*
+* Issues a synchronous read request for an input attribute. Returns
+* data upto 32 bits. Since client can get events, so this call should
+* not be used for data paths, this will impact performance.
+*/
+
+int sensor_hub_input_attr_get_raw_value(struct hid_sensor_hub_device *hsdev,
+			u32 usage_id,
+			u32 attr_usage_id, u32 report_id);
+/**
+* sensor_hub_set_feature() - Feature set request
+* @report_id:	Report id to look for
+* @field_index:	Field index inside a report
+* @value:	Value to set
+*
+* Used to set a field in feature report. For example this can set polling
+* interval, sensitivity, activate/deactivate state.
+*/
+int sensor_hub_set_feature(struct hid_sensor_hub_device *hsdev, u32 report_id,
+			u32 field_index, s32 value);
+
+/**
+* sensor_hub_get_feature() - Feature get request
+* @report_id:	Report id to look for
+* @field_index:	Field index inside a report
+* @value:	Place holder for return value
+*
+* Used to get a field in feature report. For example this can get polling
+* interval, sensitivity, activate/deactivate state.
+*/
+int sensor_hub_get_feature(struct hid_sensor_hub_device *hsdev, u32 report_id,
+			u32 field_index, s32 *value);
+#endif

include/linux/hid-sensor-ids.h

···
+/*
+ * HID Sensors Driver
+ * Copyright (c) 2012, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+#ifndef _HID_SENSORS_IDS_H
+#define _HID_SENSORS_IDS_H
+
+#define HID_UP_SENSOR						0x00200000
+#define HID_MAX_PHY_DEVICES					0xFF
+
+/* Accel 3D (200073) */
+#define HID_USAGE_SENSOR_ACCEL_3D				0x200073
+#define HID_USAGE_SENSOR_ACCEL_X_AXIS				0x200453
+#define HID_USAGE_SENSOR_ACCEL_Y_AXIS				0x200454
+#define HID_USAGE_SENSOR_ACCEL_Z_AXIS				0x200455
+
+/* ALS (200041) */
+#define HID_USAGE_SENSOR_ALS					0x200041
+#define HID_USAGE_SENSOR_LIGHT_ILLUM				0x2004d1
+
+/* Gyro 3D: (200076) */
+#define HID_USAGE_SENSOR_GYRO_3D				0x200076
+#define HID_USAGE_SENSOR_ANGL_VELOCITY_X_AXIS			0x200457
+#define HID_USAGE_SENSOR_ANGL_VELOCITY_Y_AXIS			0x200458
+#define HID_USAGE_SENSOR_ANGL_VELOCITY_Z_AXIS			0x200459
+
+/*ORIENTATION: Compass 3D: (200083) */
+#define HID_USAGE_SENSOR_COMPASS_3D				0x200083
+#define HID_USAGE_SENSOR_ORIENT_MAGN_HEADING			0x200471
+#define HID_USAGE_SENSOR_ORIENT_MAGN_HEADING_X			0x200472
+#define HID_USAGE_SENSOR_ORIENT_MAGN_HEADING_Y			0x200473
+#define HID_USAGE_SENSOR_ORIENT_MAGN_HEADING_Z			0x200474
+
+#define HID_USAGE_SENSOR_ORIENT_COMP_MAGN_NORTH			0x200475
+#define HID_USAGE_SENSOR_ORIENT_COMP_TRUE_NORTH			0x200476
+#define HID_USAGE_SENSOR_ORIENT_MAGN_NORTH			0x200477
+#define HID_USAGE_SENSOR_ORIENT_TRUE_NORTH			0x200478
+
+#define HID_USAGE_SENSOR_ORIENT_DISTANCE			0x200479
+#define HID_USAGE_SENSOR_ORIENT_DISTANCE_X			0x20047A
+#define HID_USAGE_SENSOR_ORIENT_DISTANCE_Y			0x20047B
+#define HID_USAGE_SENSOR_ORIENT_DISTANCE_Z			0x20047C
+#define HID_USAGE_SENSOR_ORIENT_DISTANCE_OUT_OF_RANGE		0x20047D
+#define HID_USAGE_SENSOR_ORIENT_TILT				0x20047E
+#define HID_USAGE_SENSOR_ORIENT_TILT_X				0x20047F
+#define HID_USAGE_SENSOR_ORIENT_TILT_Y				0x200480
+#define HID_USAGE_SENSOR_ORIENT_TILT_Z				0x200481
+#define HID_USAGE_SENSOR_ORIENT_ROTATION_MATRIX			0x200482
+#define HID_USAGE_SENSOR_ORIENT_QUATERNION			0x200483
+#define HID_USAGE_SENSOR_ORIENT_MAGN_FLUX			0x200484
+
+#define HID_USAGE_SENSOR_ORIENT_MAGN_FLUX_X_AXIS		0x200485
+#define HID_USAGE_SENSOR_ORIENT_MAGN_FLUX_Y_AXIS		0x200486
+#define HID_USAGE_SENSOR_ORIENT_MAGN_FLUX_Z_AXIS		0x200487
+
+/* Units */
+#define HID_USAGE_SENSOR_UNITS_NOT_SPECIFIED			0x00
+#define HID_USAGE_SENSOR_UNITS_LUX				0x01
+#define HID_USAGE_SENSOR_UNITS_KELVIN				0x01000100
+#define HID_USAGE_SENSOR_UNITS_FAHRENHEIT			0x03000100
+#define HID_USAGE_SENSOR_UNITS_PASCAL				0xF1E1
+#define HID_USAGE_SENSOR_UNITS_NEWTON				0x11E1
+#define HID_USAGE_SENSOR_UNITS_METERS_PER_SECOND		0x11F0
+#define HID_USAGE_SENSOR_UNITS_METERS_PER_SEC_SQRD		0x11E0
+#define HID_USAGE_SENSOR_UNITS_FARAD				0xE14F2000
+#define HID_USAGE_SENSOR_UNITS_AMPERE				0x01001000
+#define HID_USAGE_SENSOR_UNITS_WATT				0x21d1
+#define HID_USAGE_SENSOR_UNITS_HENRY				0x21E1E000
+#define HID_USAGE_SENSOR_UNITS_OHM				0x21D1E000
+#define HID_USAGE_SENSOR_UNITS_VOLT				0x21D1F000
+#define HID_USAGE_SENSOR_UNITS_HERTZ				0x01F0
+#define HID_USAGE_SENSOR_UNITS_DEGREES_PER_SEC_SQRD		0x14E0
+#define HID_USAGE_SENSOR_UNITS_RADIANS				0x12
+#define HID_USAGE_SENSOR_UNITS_RADIANS_PER_SECOND		0x12F0
+#define HID_USAGE_SENSOR_UNITS_RADIANS_PER_SEC_SQRD		0x12E0
+#define HID_USAGE_SENSOR_UNITS_SECOND				0x0110
+#define HID_USAGE_SENSOR_UNITS_GAUSS				0x01E1F000
+#define HID_USAGE_SENSOR_UNITS_GRAM				0x0101
+#define HID_USAGE_SENSOR_UNITS_CENTIMETER			0x11
+#define HID_USAGE_SENSOR_UNITS_G				0x1A
+#define HID_USAGE_SENSOR_UNITS_MILLISECOND			0x19
+#define HID_USAGE_SENSOR_UNITS_PERCENT				0x17
+#define HID_USAGE_SENSOR_UNITS_DEGREES				0x14
+#define HID_USAGE_SENSOR_UNITS_DEGREES_PER_SECOND		0x15
+
+/* Common selectors */
+#define HID_USAGE_SENSOR_PROP_REPORT_INTERVAL			0x20030E
+#define HID_USAGE_SENSOR_PROP_SENSITIVITY_ABS			0x20030F
+#define HID_USAGE_SENSOR_PROP_SENSITIVITY_RANGE_PCT		0x200310
+#define HID_USAGE_SENSOR_PROP_SENSITIVITY_REL_PCT		0x200311
+#define HID_USAGE_SENSOR_PROP_ACCURACY				0x200312
+#define HID_USAGE_SENSOR_PROP_RESOLUTION			0x200313
+#define HID_USAGE_SENSOR_PROP_RANGE_MAXIMUM			0x200314
+#define HID_USAGE_SENSOR_PROP_RANGE_MINIMUM			0x200315
+#define HID_USAGE_SENSOR_PROP_REPORT_STATE			0x200316
+#define HID_USAGE_SENSOR_PROY_POWER_STATE			0x200319
+
+#endif