diff mbox

[2/2] HID: hid-sensor-hub: Add collection device

Message ID 1420655051-6587-3-git-send-email-srinivas.pandruvada@linux.intel.com (mailing list archive)
State New, archived
Delegated to: Jiri Kosina
Headers show

Commit Message

srinivas pandruvada Jan. 7, 2015, 6:24 p.m. UTC
HID sensor hub exports several sensor which are fusion sensors, where
data is interpreted from one or more sensors. Some of them can't be
exported via IIO like sysfs as the user space download some firmware,
which defines what sensor will look like. They can be a part of a
collection.
Creating a MFD cell for a collection to write a standalone driver
to manage collections. Most of the time they will be propritery drivers
may not be even upstreamed. This patch allows framework to have
capability to write such drivers.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/hid/hid-sensor-hub.c   | 50 ++++++++++++++++++++++++++++++++++++++----
 include/linux/hid-sensor-ids.h |  2 ++
 2 files changed, 48 insertions(+), 4 deletions(-)

Comments

Jonathan Cameron Jan. 21, 2015, 9:53 p.m. UTC | #1
On 07/01/15 18:24, Srinivas Pandruvada wrote:
> HID sensor hub exports several sensor which are fusion sensors, where
> data is interpreted from one or more sensors. Some of them can't be
> exported via IIO like sysfs as the user space download some firmware,
> which defines what sensor will look like. They can be a part of a
> collection.
This functionality is beginning to turn up on a number of devices.
I'd argue that where at all possible, we should try for standard
interfaces on the resulting 'fused sensors'.  Still you do indeed
always need a means of uploading the firmware!
> Creating a MFD cell for a collection to write a standalone driver
> to manage collections. Most of the time they will be propritery drivers
> may not be even upstreamed. This patch allows framework to have
> capability to write such drivers.
> 
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
>

A few comments inline...

How does userspace download a firmware?

 
 ---
>  drivers/hid/hid-sensor-hub.c   | 50 ++++++++++++++++++++++++++++++++++++++----
>  include/linux/hid-sensor-ids.h |  2 ++
>  2 files changed, 48 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
> index 865cd56..83b6e15 100644
> --- a/drivers/hid/hid-sensor-hub.c
> +++ b/drivers/hid/hid-sensor-hub.c
> @@ -119,11 +119,12 @@ static struct hid_sensor_hub_callbacks *sensor_hub_get_callback(
>  
>  	spin_lock_irqsave(&pdata->dyn_callback_lock, flags);
>  	list_for_each_entry(callback, &pdata->dyn_callback_list, list)
> -		if (callback->usage_id == usage_id &&
> +		if (callback->usage_id == HID_USAGE_SENSOR_TYPE_COLLECTION ||
> +			(callback->usage_id == usage_id &&
>  			(collection_index >=
>  				callback->hsdev->start_collection_index) &&
>  			(collection_index <
> -				callback->hsdev->end_collection_index)) {
> +				callback->hsdev->end_collection_index))) {
>  			*priv = callback->priv;
>  			*hsdev = callback->hsdev;
>  			spin_unlock_irqrestore(&pdata->dyn_callback_lock,
> @@ -159,7 +160,12 @@ int sensor_hub_register_callback(struct hid_sensor_hub_device *hsdev,
>  	callback->usage_callback = usage_callback;
>  	callback->usage_id = usage_id;
>  	callback->priv = NULL;
> -	list_add_tail(&callback->list, &pdata->dyn_callback_list);
> +	/* Give higher priority to collection device, so add to front */
Comment should probably state why we want to give them higher priorities.

> +	if (usage_id == HID_USAGE_SENSOR_TYPE_COLLECTION)
> +		list_add(&callback->list, &pdata->dyn_callback_list);
> +	else
> +		list_add_tail(&callback->list, &pdata->dyn_callback_list);
> +
>  	spin_unlock_irqrestore(&pdata->dyn_callback_lock, flags);
>  
>  	return 0;
> @@ -547,6 +553,37 @@ static __u8 *sensor_hub_report_fixup(struct hid_device *hdev, __u8 *rdesc,
>  	return rdesc;
>  }
>  
> +static int sensor_hub_add_collection_device(struct hid_device *hdev,
> +					    struct sensor_hub_data *sd)
> +{
> +	struct hid_sensor_hub_device *hsdev;
> +	char *name;
> +
> +	hsdev = devm_kzalloc(&hdev->dev, sizeof(*hsdev), GFP_KERNEL);
> +	if (!hsdev)
> +		return -ENOMEM;
> +
> +	hsdev->hdev = hdev;
> +	hsdev->vendor_id = hdev->vendor;
> +	hsdev->product_id = hdev->product;
> +	hsdev->usage = HID_USAGE_SENSOR_TYPE_COLLECTION;
> +	mutex_init(&hsdev->mutex);
> +	name = devm_kasprintf(&hdev->dev, GFP_KERNEL, "HID-SENSOR-%x",
> +			      HID_USAGE_SENSOR_TYPE_COLLECTION);
> +	if (name == NULL) {
> +		hid_err(hdev, "Failed MFD device name\n");
> +		return -ENOMEM;
> +	}
> +	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 = hsdev;
Odd breaking up of the line...  Perhaps break before .platform_data instead?
> +	sd->hid_sensor_hub_client_devs[
> +			sd->hid_sensor_client_cnt].pdata_size = sizeof(*hsdev);
> +	sd->hid_sensor_client_cnt++;
> +
> +	return 0;
> +}
> +
>  static int sensor_hub_probe(struct hid_device *hdev,
>  				const struct hid_device_id *id)
>  {
> @@ -591,7 +628,8 @@ static int sensor_hub_probe(struct hid_device *hdev,
>  		ret = -EINVAL;
>  		goto err_stop_hw;
>  	}
> -	sd->hid_sensor_hub_client_devs = devm_kzalloc(&hdev->dev, dev_cnt *
> +	sd->hid_sensor_hub_client_devs = devm_kzalloc(&hdev->dev,
> +						      (dev_cnt + 1) *
>  						      sizeof(struct mfd_cell),
>  						      GFP_KERNEL);
>  	if (sd->hid_sensor_hub_client_devs == NULL) {
> @@ -645,6 +683,10 @@ static int sensor_hub_probe(struct hid_device *hdev,
>  	if (last_hsdev)
>  		last_hsdev->end_collection_index = i;
>  
> +	ret = sensor_hub_add_collection_device(hdev, sd);
> +	if (ret)
> +		goto err_stop_hw;
> +
>  	ret = mfd_add_hotplug_devices(&hdev->dev,
>  			sd->hid_sensor_hub_client_devs,
>  			sd->hid_sensor_client_cnt);
> diff --git a/include/linux/hid-sensor-ids.h b/include/linux/hid-sensor-ids.h
> index 109f0e6..300ffea 100644
> --- a/include/linux/hid-sensor-ids.h
> +++ b/include/linux/hid-sensor-ids.h
> @@ -21,6 +21,8 @@
>  
>  #define HID_MAX_PHY_DEVICES					0xFF
>  
> +#define HID_USAGE_SENSOR_TYPE_COLLECTION			0x200001
> +
>  /* Accel 3D (200073) */
>  #define HID_USAGE_SENSOR_ACCEL_3D				0x200073
>  #define HID_USAGE_SENSOR_DATA_ACCELERATION			0x200452
> 

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Jiri Kosina Feb. 17, 2015, 12:36 p.m. UTC | #2
On Wed, 21 Jan 2015, Jonathan Cameron wrote:

> On 07/01/15 18:24, Srinivas Pandruvada wrote:
> > HID sensor hub exports several sensor which are fusion sensors, where
> > data is interpreted from one or more sensors. Some of them can't be
> > exported via IIO like sysfs as the user space download some firmware,
> > which defines what sensor will look like. They can be a part of a
> > collection.
> This functionality is beginning to turn up on a number of devices.
> I'd argue that where at all possible, we should try for standard
> interfaces on the resulting 'fused sensors'.  Still you do indeed
> always need a means of uploading the firmware!
> > Creating a MFD cell for a collection to write a standalone driver
> > to manage collections. Most of the time they will be propritery drivers
> > may not be even upstreamed. This patch allows framework to have
> > capability to write such drivers.

Srinivas, do you plan to respond to the comments Jonathan had on this 
patch?

Thanks.
srinivas pandruvada Feb. 19, 2015, 11:54 p.m. UTC | #3
On Wed, 2015-01-21 at 21:53 +0000, Jonathan Cameron wrote:
> On 07/01/15 18:24, Srinivas Pandruvada wrote:
> > HID sensor hub exports several sensor which are fusion sensors, where
> > data is interpreted from one or more sensors. Some of them can't be
> > exported via IIO like sysfs as the user space download some firmware,
> > which defines what sensor will look like. They can be a part of a
> > collection.
> This functionality is beginning to turn up on a number of devices.
> I'd argue that where at all possible, we should try for standard
> interfaces on the resulting 'fused sensors'.  Still you do indeed
> always need a means of uploading the firmware!
I will submitted RFCs, once I see in production releases.

Currently planning to use misc driver for FW update.
What do you think about using dev/iio:deviceX for such case to download
FW for each sensor? We also need mechanism to initiate and reset after
FW download.

Thanks,
Srinivas

> > Creating a MFD cell for a collection to write a standalone driver
> > to manage collections. Most of the time they will be propritery drivers
> > may not be even upstreamed. This patch allows framework to have
> > capability to write such drivers.
> > 
> > Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> >
> 
> A few comments inline...
> 
> How does userspace download a firmware?
> 
>  
>  ---
> >  drivers/hid/hid-sensor-hub.c   | 50 ++++++++++++++++++++++++++++++++++++++----
> >  include/linux/hid-sensor-ids.h |  2 ++
> >  2 files changed, 48 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
> > index 865cd56..83b6e15 100644
> > --- a/drivers/hid/hid-sensor-hub.c
> > +++ b/drivers/hid/hid-sensor-hub.c
> > @@ -119,11 +119,12 @@ static struct hid_sensor_hub_callbacks *sensor_hub_get_callback(
> >  
> >  	spin_lock_irqsave(&pdata->dyn_callback_lock, flags);
> >  	list_for_each_entry(callback, &pdata->dyn_callback_list, list)
> > -		if (callback->usage_id == usage_id &&
> > +		if (callback->usage_id == HID_USAGE_SENSOR_TYPE_COLLECTION ||
> > +			(callback->usage_id == usage_id &&
> >  			(collection_index >=
> >  				callback->hsdev->start_collection_index) &&
> >  			(collection_index <
> > -				callback->hsdev->end_collection_index)) {
> > +				callback->hsdev->end_collection_index))) {
> >  			*priv = callback->priv;
> >  			*hsdev = callback->hsdev;
> >  			spin_unlock_irqrestore(&pdata->dyn_callback_lock,
> > @@ -159,7 +160,12 @@ int sensor_hub_register_callback(struct hid_sensor_hub_device *hsdev,
> >  	callback->usage_callback = usage_callback;
> >  	callback->usage_id = usage_id;
> >  	callback->priv = NULL;
> > -	list_add_tail(&callback->list, &pdata->dyn_callback_list);
> > +	/* Give higher priority to collection device, so add to front */
> Comment should probably state why we want to give them higher priorities.
> 
> > +	if (usage_id == HID_USAGE_SENSOR_TYPE_COLLECTION)
> > +		list_add(&callback->list, &pdata->dyn_callback_list);
> > +	else
> > +		list_add_tail(&callback->list, &pdata->dyn_callback_list);
> > +
> >  	spin_unlock_irqrestore(&pdata->dyn_callback_lock, flags);
> >  
> >  	return 0;
> > @@ -547,6 +553,37 @@ static __u8 *sensor_hub_report_fixup(struct hid_device *hdev, __u8 *rdesc,
> >  	return rdesc;
> >  }
> >  
> > +static int sensor_hub_add_collection_device(struct hid_device *hdev,
> > +					    struct sensor_hub_data *sd)
> > +{
> > +	struct hid_sensor_hub_device *hsdev;
> > +	char *name;
> > +
> > +	hsdev = devm_kzalloc(&hdev->dev, sizeof(*hsdev), GFP_KERNEL);
> > +	if (!hsdev)
> > +		return -ENOMEM;
> > +
> > +	hsdev->hdev = hdev;
> > +	hsdev->vendor_id = hdev->vendor;
> > +	hsdev->product_id = hdev->product;
> > +	hsdev->usage = HID_USAGE_SENSOR_TYPE_COLLECTION;
> > +	mutex_init(&hsdev->mutex);
> > +	name = devm_kasprintf(&hdev->dev, GFP_KERNEL, "HID-SENSOR-%x",
> > +			      HID_USAGE_SENSOR_TYPE_COLLECTION);
> > +	if (name == NULL) {
> > +		hid_err(hdev, "Failed MFD device name\n");
> > +		return -ENOMEM;
> > +	}
> > +	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 = hsdev;
> Odd breaking up of the line...  Perhaps break before .platform_data instead?
> > +	sd->hid_sensor_hub_client_devs[
> > +			sd->hid_sensor_client_cnt].pdata_size = sizeof(*hsdev);
> > +	sd->hid_sensor_client_cnt++;
> > +
> > +	return 0;
> > +}
> > +
> >  static int sensor_hub_probe(struct hid_device *hdev,
> >  				const struct hid_device_id *id)
> >  {
> > @@ -591,7 +628,8 @@ static int sensor_hub_probe(struct hid_device *hdev,
> >  		ret = -EINVAL;
> >  		goto err_stop_hw;
> >  	}
> > -	sd->hid_sensor_hub_client_devs = devm_kzalloc(&hdev->dev, dev_cnt *
> > +	sd->hid_sensor_hub_client_devs = devm_kzalloc(&hdev->dev,
> > +						      (dev_cnt + 1) *
> >  						      sizeof(struct mfd_cell),
> >  						      GFP_KERNEL);
> >  	if (sd->hid_sensor_hub_client_devs == NULL) {
> > @@ -645,6 +683,10 @@ static int sensor_hub_probe(struct hid_device *hdev,
> >  	if (last_hsdev)
> >  		last_hsdev->end_collection_index = i;
> >  
> > +	ret = sensor_hub_add_collection_device(hdev, sd);
> > +	if (ret)
> > +		goto err_stop_hw;
> > +
> >  	ret = mfd_add_hotplug_devices(&hdev->dev,
> >  			sd->hid_sensor_hub_client_devs,
> >  			sd->hid_sensor_client_cnt);
> > diff --git a/include/linux/hid-sensor-ids.h b/include/linux/hid-sensor-ids.h
> > index 109f0e6..300ffea 100644
> > --- a/include/linux/hid-sensor-ids.h
> > +++ b/include/linux/hid-sensor-ids.h
> > @@ -21,6 +21,8 @@
> >  
> >  #define HID_MAX_PHY_DEVICES					0xFF
> >  
> > +#define HID_USAGE_SENSOR_TYPE_COLLECTION			0x200001
> > +
> >  /* Accel 3D (200073) */
> >  #define HID_USAGE_SENSOR_ACCEL_3D				0x200073
> >  #define HID_USAGE_SENSOR_DATA_ACCELERATION			0x200452
> > 
> 


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Jonathan Cameron Feb. 21, 2015, 7:09 p.m. UTC | #4
On 19/02/15 23:54, Srinivas Pandruvada wrote:
> On Wed, 2015-01-21 at 21:53 +0000, Jonathan Cameron wrote:
>> On 07/01/15 18:24, Srinivas Pandruvada wrote:
>>> HID sensor hub exports several sensor which are fusion sensors, where
>>> data is interpreted from one or more sensors. Some of them can't be
>>> exported via IIO like sysfs as the user space download some firmware,
>>> which defines what sensor will look like. They can be a part of a
>>> collection.
>> This functionality is beginning to turn up on a number of devices.
>> I'd argue that where at all possible, we should try for standard
>> interfaces on the resulting 'fused sensors'.  Still you do indeed
>> always need a means of uploading the firmware!
> I will submitted RFCs, once I see in production releases.
Cool
> 
> Currently planning to use misc driver for FW update.
> What do you think about using dev/iio:deviceX for such case to download
> FW for each sensor? We also need mechanism to initiate and reset after
> FW download.
I think using the main iio device is pushing things a little.  We could add
the ability to get another anonymous cdev like we do for events I suppose.
That way, at least it will be tied to the normal iio device.

Sort of feels like there should be a generic / standard way of doing
this sort of firmware update, irrespective of what the device does.
I guess, maybe it's always non generic enough that this isn't
possible.
> 
> Thanks,
> Srinivas
> 
>>> Creating a MFD cell for a collection to write a standalone driver
>>> to manage collections. Most of the time they will be propritery drivers
>>> may not be even upstreamed. This patch allows framework to have
>>> capability to write such drivers.
>>>
>>> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
>>>
>>
>> A few comments inline...
>>
>> How does userspace download a firmware?
>>
>>  
>>  ---
>>>  drivers/hid/hid-sensor-hub.c   | 50 ++++++++++++++++++++++++++++++++++++++----
>>>  include/linux/hid-sensor-ids.h |  2 ++
>>>  2 files changed, 48 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
>>> index 865cd56..83b6e15 100644
>>> --- a/drivers/hid/hid-sensor-hub.c
>>> +++ b/drivers/hid/hid-sensor-hub.c
>>> @@ -119,11 +119,12 @@ static struct hid_sensor_hub_callbacks *sensor_hub_get_callback(
>>>  
>>>  	spin_lock_irqsave(&pdata->dyn_callback_lock, flags);
>>>  	list_for_each_entry(callback, &pdata->dyn_callback_list, list)
>>> -		if (callback->usage_id == usage_id &&
>>> +		if (callback->usage_id == HID_USAGE_SENSOR_TYPE_COLLECTION ||
>>> +			(callback->usage_id == usage_id &&
>>>  			(collection_index >=
>>>  				callback->hsdev->start_collection_index) &&
>>>  			(collection_index <
>>> -				callback->hsdev->end_collection_index)) {
>>> +				callback->hsdev->end_collection_index))) {
>>>  			*priv = callback->priv;
>>>  			*hsdev = callback->hsdev;
>>>  			spin_unlock_irqrestore(&pdata->dyn_callback_lock,
>>> @@ -159,7 +160,12 @@ int sensor_hub_register_callback(struct hid_sensor_hub_device *hsdev,
>>>  	callback->usage_callback = usage_callback;
>>>  	callback->usage_id = usage_id;
>>>  	callback->priv = NULL;
>>> -	list_add_tail(&callback->list, &pdata->dyn_callback_list);
>>> +	/* Give higher priority to collection device, so add to front */
>> Comment should probably state why we want to give them higher priorities.
>>
>>> +	if (usage_id == HID_USAGE_SENSOR_TYPE_COLLECTION)
>>> +		list_add(&callback->list, &pdata->dyn_callback_list);
>>> +	else
>>> +		list_add_tail(&callback->list, &pdata->dyn_callback_list);
>>> +
>>>  	spin_unlock_irqrestore(&pdata->dyn_callback_lock, flags);
>>>  
>>>  	return 0;
>>> @@ -547,6 +553,37 @@ static __u8 *sensor_hub_report_fixup(struct hid_device *hdev, __u8 *rdesc,
>>>  	return rdesc;
>>>  }
>>>  
>>> +static int sensor_hub_add_collection_device(struct hid_device *hdev,
>>> +					    struct sensor_hub_data *sd)
>>> +{
>>> +	struct hid_sensor_hub_device *hsdev;
>>> +	char *name;
>>> +
>>> +	hsdev = devm_kzalloc(&hdev->dev, sizeof(*hsdev), GFP_KERNEL);
>>> +	if (!hsdev)
>>> +		return -ENOMEM;
>>> +
>>> +	hsdev->hdev = hdev;
>>> +	hsdev->vendor_id = hdev->vendor;
>>> +	hsdev->product_id = hdev->product;
>>> +	hsdev->usage = HID_USAGE_SENSOR_TYPE_COLLECTION;
>>> +	mutex_init(&hsdev->mutex);
>>> +	name = devm_kasprintf(&hdev->dev, GFP_KERNEL, "HID-SENSOR-%x",
>>> +			      HID_USAGE_SENSOR_TYPE_COLLECTION);
>>> +	if (name == NULL) {
>>> +		hid_err(hdev, "Failed MFD device name\n");
>>> +		return -ENOMEM;
>>> +	}
>>> +	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 = hsdev;
>> Odd breaking up of the line...  Perhaps break before .platform_data instead?
>>> +	sd->hid_sensor_hub_client_devs[
>>> +			sd->hid_sensor_client_cnt].pdata_size = sizeof(*hsdev);
>>> +	sd->hid_sensor_client_cnt++;
>>> +
>>> +	return 0;
>>> +}
>>> +
>>>  static int sensor_hub_probe(struct hid_device *hdev,
>>>  				const struct hid_device_id *id)
>>>  {
>>> @@ -591,7 +628,8 @@ static int sensor_hub_probe(struct hid_device *hdev,
>>>  		ret = -EINVAL;
>>>  		goto err_stop_hw;
>>>  	}
>>> -	sd->hid_sensor_hub_client_devs = devm_kzalloc(&hdev->dev, dev_cnt *
>>> +	sd->hid_sensor_hub_client_devs = devm_kzalloc(&hdev->dev,
>>> +						      (dev_cnt + 1) *
>>>  						      sizeof(struct mfd_cell),
>>>  						      GFP_KERNEL);
>>>  	if (sd->hid_sensor_hub_client_devs == NULL) {
>>> @@ -645,6 +683,10 @@ static int sensor_hub_probe(struct hid_device *hdev,
>>>  	if (last_hsdev)
>>>  		last_hsdev->end_collection_index = i;
>>>  
>>> +	ret = sensor_hub_add_collection_device(hdev, sd);
>>> +	if (ret)
>>> +		goto err_stop_hw;
>>> +
>>>  	ret = mfd_add_hotplug_devices(&hdev->dev,
>>>  			sd->hid_sensor_hub_client_devs,
>>>  			sd->hid_sensor_client_cnt);
>>> diff --git a/include/linux/hid-sensor-ids.h b/include/linux/hid-sensor-ids.h
>>> index 109f0e6..300ffea 100644
>>> --- a/include/linux/hid-sensor-ids.h
>>> +++ b/include/linux/hid-sensor-ids.h
>>> @@ -21,6 +21,8 @@
>>>  
>>>  #define HID_MAX_PHY_DEVICES					0xFF
>>>  
>>> +#define HID_USAGE_SENSOR_TYPE_COLLECTION			0x200001
>>> +
>>>  /* Accel 3D (200073) */
>>>  #define HID_USAGE_SENSOR_ACCEL_3D				0x200073
>>>  #define HID_USAGE_SENSOR_DATA_ACCELERATION			0x200452
>>>
>>
> 
> 

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diff mbox

Patch

diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
index 865cd56..83b6e15 100644
--- a/drivers/hid/hid-sensor-hub.c
+++ b/drivers/hid/hid-sensor-hub.c
@@ -119,11 +119,12 @@  static struct hid_sensor_hub_callbacks *sensor_hub_get_callback(
 
 	spin_lock_irqsave(&pdata->dyn_callback_lock, flags);
 	list_for_each_entry(callback, &pdata->dyn_callback_list, list)
-		if (callback->usage_id == usage_id &&
+		if (callback->usage_id == HID_USAGE_SENSOR_TYPE_COLLECTION ||
+			(callback->usage_id == usage_id &&
 			(collection_index >=
 				callback->hsdev->start_collection_index) &&
 			(collection_index <
-				callback->hsdev->end_collection_index)) {
+				callback->hsdev->end_collection_index))) {
 			*priv = callback->priv;
 			*hsdev = callback->hsdev;
 			spin_unlock_irqrestore(&pdata->dyn_callback_lock,
@@ -159,7 +160,12 @@  int sensor_hub_register_callback(struct hid_sensor_hub_device *hsdev,
 	callback->usage_callback = usage_callback;
 	callback->usage_id = usage_id;
 	callback->priv = NULL;
-	list_add_tail(&callback->list, &pdata->dyn_callback_list);
+	/* Give higher priority to collection device, so add to front */
+	if (usage_id == HID_USAGE_SENSOR_TYPE_COLLECTION)
+		list_add(&callback->list, &pdata->dyn_callback_list);
+	else
+		list_add_tail(&callback->list, &pdata->dyn_callback_list);
+
 	spin_unlock_irqrestore(&pdata->dyn_callback_lock, flags);
 
 	return 0;
@@ -547,6 +553,37 @@  static __u8 *sensor_hub_report_fixup(struct hid_device *hdev, __u8 *rdesc,
 	return rdesc;
 }
 
+static int sensor_hub_add_collection_device(struct hid_device *hdev,
+					    struct sensor_hub_data *sd)
+{
+	struct hid_sensor_hub_device *hsdev;
+	char *name;
+
+	hsdev = devm_kzalloc(&hdev->dev, sizeof(*hsdev), GFP_KERNEL);
+	if (!hsdev)
+		return -ENOMEM;
+
+	hsdev->hdev = hdev;
+	hsdev->vendor_id = hdev->vendor;
+	hsdev->product_id = hdev->product;
+	hsdev->usage = HID_USAGE_SENSOR_TYPE_COLLECTION;
+	mutex_init(&hsdev->mutex);
+	name = devm_kasprintf(&hdev->dev, GFP_KERNEL, "HID-SENSOR-%x",
+			      HID_USAGE_SENSOR_TYPE_COLLECTION);
+	if (name == NULL) {
+		hid_err(hdev, "Failed MFD device name\n");
+		return -ENOMEM;
+	}
+	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 = hsdev;
+	sd->hid_sensor_hub_client_devs[
+			sd->hid_sensor_client_cnt].pdata_size = sizeof(*hsdev);
+	sd->hid_sensor_client_cnt++;
+
+	return 0;
+}
+
 static int sensor_hub_probe(struct hid_device *hdev,
 				const struct hid_device_id *id)
 {
@@ -591,7 +628,8 @@  static int sensor_hub_probe(struct hid_device *hdev,
 		ret = -EINVAL;
 		goto err_stop_hw;
 	}
-	sd->hid_sensor_hub_client_devs = devm_kzalloc(&hdev->dev, dev_cnt *
+	sd->hid_sensor_hub_client_devs = devm_kzalloc(&hdev->dev,
+						      (dev_cnt + 1) *
 						      sizeof(struct mfd_cell),
 						      GFP_KERNEL);
 	if (sd->hid_sensor_hub_client_devs == NULL) {
@@ -645,6 +683,10 @@  static int sensor_hub_probe(struct hid_device *hdev,
 	if (last_hsdev)
 		last_hsdev->end_collection_index = i;
 
+	ret = sensor_hub_add_collection_device(hdev, sd);
+	if (ret)
+		goto err_stop_hw;
+
 	ret = mfd_add_hotplug_devices(&hdev->dev,
 			sd->hid_sensor_hub_client_devs,
 			sd->hid_sensor_client_cnt);
diff --git a/include/linux/hid-sensor-ids.h b/include/linux/hid-sensor-ids.h
index 109f0e6..300ffea 100644
--- a/include/linux/hid-sensor-ids.h
+++ b/include/linux/hid-sensor-ids.h
@@ -21,6 +21,8 @@ 
 
 #define HID_MAX_PHY_DEVICES					0xFF
 
+#define HID_USAGE_SENSOR_TYPE_COLLECTION			0x200001
+
 /* Accel 3D (200073) */
 #define HID_USAGE_SENSOR_ACCEL_3D				0x200073
 #define HID_USAGE_SENSOR_DATA_ACCELERATION			0x200452