Documentation/hid/hid-alps.rst

Source file repositories/reference/linux-study-clean/Documentation/hid/hid-alps.rst

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Linux kernel
Corpus path
Documentation/hid/hid-alps.rst
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.rst
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5418 bytes
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185
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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Annotated Snippet

==========================
ALPS HID Touchpad Protocol
==========================

Introduction
------------
Currently ALPS HID driver supports U1 Touchpad device.

U1 device basic information.

==========	======
Vendor ID	0x044E
Product ID	0x120B
Version ID	0x0121
==========	======


HID Descriptor
--------------

=======	====================	=====	=======================================
Byte	Field			Value	Notes
=======	====================	=====	=======================================
0	wHIDDescLength		001E	Length of HID Descriptor : 30 bytes
2	bcdVersion		0100	Compliant with Version 1.00
4	wReportDescLength	00B2	Report Descriptor is 178 Bytes (0x00B2)
6	wReportDescRegister	0002	Identifier to read Report Descriptor
8	wInputRegister		0003	Identifier to read Input Report
10	wMaxInputLength		0053	Input Report is 80 Bytes + 2
12	wOutputRegister		0000	Identifier to read Output Report
14	wMaxOutputLength	0000	No Output Reports
16	wCommandRegister	0005	Identifier for Command Register
18	wDataRegister		0006	Identifier for Data Register
20	wVendorID		044E	Vendor ID 0x044E
22	wProductID		120B	Product ID 0x120B
24	wVersionID		0121	Version 01.21
26	RESERVED		0000	RESERVED
=======	====================	=====	=======================================


Report ID
---------

==========	=================  =========================================
ReportID-1	(Input Reports)	   (HIDUsage-Mouse) for TP&SP
ReportID-2	(Input Reports)	   (HIDUsage-keyboard) for TP
ReportID-3	(Input Reports)	   (Vendor Usage: Max 10 finger data) for TP
ReportID-4	(Input Reports)	   (Vendor Usage: ON bit data) for GP
ReportID-5	(Feature Reports)  Feature Reports
ReportID-6	(Input Reports)	   (Vendor Usage: StickPointer data) for SP
ReportID-7	(Feature Reports)  Flash update (Bootloader)
==========	=================  =========================================


Data pattern
------------

=====	==========	=====	=================
Case1	ReportID_1	TP/SP	Relative/Relative
Case2	ReportID_3	TP	Absolute
	ReportID_6	SP	Absolute
=====	==========	=====	=================


Command Read/Write
------------------
To read/write to RAM, need to send a command to the device.

The command format is as below.

Annotation

Implementation Notes