Documentation/hid/hid-sensor.rst

2 HID Sensors Framework
4 HID sensor framework provides necessary interfaces to implement sensor drivers,
5 which are connected to a sensor hub. The sensor hub is a HID device and it provides
6 a report descriptor conforming to HID 1.12 sensor usage tables.
8 Description from the HID 1.12 "HID Sensor Usages" specification:
9 "Standardization of HID usages for sensors would allow (but not require) sensor
26         Logical Minimum(-32767)
35 The report is indicating "sensor page (0x20)" contains an accelerometer-3D (0x73).
36 This accelerometer-3D has some fields. Here for example field 2 is motion intensity
37 (0x045f) with a logical minimum value of -32767 and logical maximum of 32767. The
51 - Core HID driver
52 - Individual sensor processing part (sensor drivers)
55 -----------
56 The core driver (hid-sensor-hub) registers as a HID driver. It parses
58 with name HID-SENSOR-xxxx (where xxxx is usage id from the specification).
62 HID-SENSOR-200073 is registered for an Accelerometer 3D driver.
66 with this name and will be probed if there is an accelerometer-3D detected.
73 --------------------------------------------------
86 	int (*suspend)(..): Callback when HID suspend is received
87 	int (*resume)(..): Callback when HID resume is received
147 the usage id of X axis. HID sensors can provide events, so this is not necessary
152 ----------
154 HID Custom and generic Sensors
155 ------------------------------
158 HID Sensor specification defines two special sensor usage types. Since they
174 …/sys/devices/pci0000:00/INT33C2:00/i2c-0/i2c-INT33D1:00/0018:8086:09FA.0001/HID-SENSOR-2000e1.6.au…
177   │   │   ├── feature-0-200316
178   │   │   │   ├── feature-0-200316-maximum
179   │   │   │   ├── feature-0-200316-minimum
180   │   │   │   ├── feature-0-200316-name
181   │   │   │   ├── feature-0-200316-size
182   │   │   │   ├── feature-0-200316-unit-expo
183   │   │   │   ├── feature-0-200316-units
184   │   │   │   ├── feature-0-200316-value
185   │   │   ├── feature-1-200201
186   │   │   │   ├── feature-1-200201-maximum
187   │   │   │   ├── feature-1-200201-minimum
188   │   │   │   ├── feature-1-200201-name
189   │   │   │   ├── feature-1-200201-size
190   │   │   │   ├── feature-1-200201-unit-expo
191   │   │   │   ├── feature-1-200201-units
192   │   │   │   ├── feature-1-200201-value
193   │   │   ├── input-0-200201
194   │   │   │   ├── input-0-200201-maximum
195   │   │   │   ├── input-0-200201-minimum
196   │   │   │   ├── input-0-200201-name
197   │   │   │   ├── input-0-200201-size
198   │   │   │   ├── input-0-200201-unit-expo
199   │   │   │   ├── input-0-200201-units
200   │   │   │   ├── input-0-200201-value
201   │   │   ├── input-1-200202
202   │   │   │   ├── input-1-200202-maximum
203   │   │   │   ├── input-1-200202-minimum
204   │   │   │   ├── input-1-200202-name
205   │   │   │   ├── input-1-200202-size
206   │   │   │   ├── input-1-200202-unit-expo
207   │   │   │   ├── input-1-200202-units
208   │   │   │   ├── input-1-200202-value
212 are read only. The value field is a read-write field.
216   /sys/bus/platform/devices/HID-SENSOR-2000e1.6.auto/feature-0-200316$ grep -r . *
217   feature-0-200316-maximum:6
218   feature-0-200316-minimum:0
219   feature-0-200316-name:property-reporting-state
220   feature-0-200316-size:1
221   feature-0-200316-unit-expo:0
222   feature-0-200316-units:25
223   feature-0-200316-value:1
233 Once enabled and powered on, sensor can report value using HID reports.
236 	/dev$ tree | grep HID-SENSOR-2000e1.6.auto
237 	│   │   │   ├── 10:53 -> ../HID-SENSOR-2000e1.6.auto
238 	│   ├──  HID-SENSOR-2000e1.6.auto
241 consists of a 32-bit usage id, 64-bit time stamp and 32-bit length field of raw