Merge branch 'for-4.1/sensor-hub' into for-linus

the usage id of X axis. HID sensors can provide events, so this is not necessary

to poll for any field. If there is some new sample, the core driver will call

registered callback function to process the sample.

----------

HID Custom and generic Sensors

HID Sensor specification defines two special sensor usage types. Since they

don't represent a standard sensor, it is not possible to define using Linux IIO

type interfaces.

The purpose of these sensors is to extend the functionality or provide a

way to obfuscate the data being communicated by a sensor. Without knowing the

mapping between the data and its encapsulated form, it is difficult for

an application/driver to determine what data is being communicated by the sensor.

This allows some differentiating use cases, where vendor can provide applications.

Some common use cases are debug other sensors or to provide some events like

keyboard attached/detached or lid open/close.

To allow application to utilize these sensors, here they are exported uses sysfs

attribute groups, attributes and misc device interface.

An example of this representation on sysfs:

/sys/devices/pci0000:00/INT33C2:00/i2c-0/i2c-INT33D1:00/0018:8086:09FA.0001/HID-SENSOR-2000e1.6.auto$ tree -R

.

????????? enable_sensor

????????? feature-0-200316

??????? ????????? feature-0-200316-maximum

??????? ????????? feature-0-200316-minimum

??????? ????????? feature-0-200316-name

??????? ????????? feature-0-200316-size

??????? ????????? feature-0-200316-unit-expo

??????? ????????? feature-0-200316-units

??????? ????????? feature-0-200316-value

????????? feature-1-200201

??????? ????????? feature-1-200201-maximum

??????? ????????? feature-1-200201-minimum

??????? ????????? feature-1-200201-name

??????? ????????? feature-1-200201-size

??????? ????????? feature-1-200201-unit-expo

??????? ????????? feature-1-200201-units

??????? ????????? feature-1-200201-value

????????? input-0-200201

??????? ????????? input-0-200201-maximum

??????? ????????? input-0-200201-minimum

??????? ????????? input-0-200201-name

??????? ????????? input-0-200201-size

??????? ????????? input-0-200201-unit-expo

??????? ????????? input-0-200201-units

??????? ????????? input-0-200201-value

????????? input-1-200202

??????? ????????? input-1-200202-maximum

??????? ????????? input-1-200202-minimum

??????? ????????? input-1-200202-name

??????? ????????? input-1-200202-size

??????? ????????? input-1-200202-unit-expo

??????? ????????? input-1-200202-units

??????? ????????? input-1-200202-value

Here there is a custom sensors with four fields, two feature and two inputs.

Each field is represented by a set of attributes. All fields except the "value"

are read only. The value field is a RW field.

Example

/sys/bus/platform/devices/HID-SENSOR-2000e1.6.auto/feature-0-200316$ grep -r . *

feature-0-200316-maximum:6

feature-0-200316-minimum:0

feature-0-200316-name:property-reporting-state

feature-0-200316-size:1

feature-0-200316-unit-expo:0

feature-0-200316-units:25

feature-0-200316-value:1

How to enable such sensor?

By default sensor can be power gated. To enable sysfs attribute "enable" can be

used.

$ echo 1 > enable_sensor

Once enabled and powered on, sensor can report value using HID reports.

These reports are pushed using misc device interface in a FIFO order.

/dev$ tree | grep HID-SENSOR-2000e1.6.auto

??????? ????????? 10:53 -> ../HID-SENSOR-2000e1.6.auto

????????? HID-SENSOR-2000e1.6.auto

Each reports can be of variable length preceded by a header. This header

consist of a 32 bit usage id, 64 bit time stamp and 32 bit length field of raw

data.

	  for events and handle data streams. Each sensor driver can format

	  data and present to user mode using input or IIO interface.

config HID_SENSOR_CUSTOM_SENSOR

	tristate "HID Sensors hub custom sensor support"

	depends on HID_SENSOR_HUB

	default n

	---help---

	  HID Sensor hub specification allows definition of some custom and

	  generic sensors. Unlike other HID sensors, they can't be exported

	  via Linux IIO because of custom fields. This is up to the manufacturer

	  to decide how to interpret these special sensor ids and process in

	  the user space. Currently some manufacturers are using these ids for

	  sensor calibration and debugging other sensors. Manufacturers

	  should't use these special custom sensor ids to export any of the

	  standard sensors.

	  Select this config option for custom/generic sensor support.

endmenu

endif # HID

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_HID_SENSOR_CUSTOM_SENSOR)	+= hid-sensor-custom.o

obj-$(CONFIG_USB_HID)		+= usbhid/

obj-$(CONFIG_USB_MOUSE)		+= usbhid/