path: root/arch/arm/mach-s3c2440/s3c HID Sensors Framework ====================== HID sensor framework provides necessary interfaces to implement sensor drivers, which are connected to a sensor hub. The sensor hub is a HID device and it provides a report descriptor conforming to HID 1.12 sensor usage tables. Description from the HID 1.12 "HID Sensor Usages" specification: "Standardization of HID usages for sensors would allow (but not require) sensor hardware vendors to provide a consistent Plug And Play interface at the USB boundary, thereby enabling some operating systems to incorporate common device drivers that could be reused between vendors, alleviating any need for the vendors to provide the drivers themselves." This specification describes many usage IDs, which describe the type of sensor and also the individual data fields. Each sensor can have variable number of data fields. The length and order is specified in the report descriptor. For example a part of report descriptor can look like: INPUT(1)[INPUT] .. Field(2) Physical(0020.0073) Usage(1) 0020.045f Logical Minimum(-32767) Logical Maximum(32767) Report Size(8) Report Count(1) Report Offset(16) Flags(Variable Absolute) .. .. The report is indicating "sensor page (0x20)" contains an accelerometer-3D (0x73). This accelerometer-3D has some fields. Here for example field 2 is motion intensity (0x045f) with a logical minimum value of -32767 and