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/* SPDX-License-Identifier: GPL-2.0-only */
/* This file is part of the coreboot project. */
Scope (\_SB)
{
/*
* Chrome EC Keyboard Backlight interface
*/
Device (KBLT)
{
Name (_HID, "GOOG0002")
Name (_UID, 1)
/* Ask EC if we even have a backlight
* Return 0xf (present, enabled, show in UI, functioning) or 0
*
* With older EC codebases that don't support the Device
* Features bitfield, this reports the keyboard backlight as
* enabled since reads to undefined addresses in EC address
* space return 0xff and so KBLE will be 1.
*/
Method (_STA, 0, NotSerialized)
{
/* If query is unsupported, but this code is compiled
* in, assume the backlight exists physically.
*/
If (LEqual (1, \_SB.PCI0.LPCB.EC0.DFUD)) {
Return (0xf)
}
/* If EC reports that backlight exists, trust it */
If (LEqual (1, \_SB.PCI0.LPCB.EC0.KBLE)) {
Return (0xf)
}
/* Otherwise: no device -> disable */
Return (0)
}
/* Read current backlight value */
Method (KBQC, 0, NotSerialized)
{
Return (\_SB.PCI0.LPCB.EC0.KBLV)
}
/* Write new backlight value */
Method (KBCM, 1, NotSerialized)
{
Store (Arg0, \_SB.PCI0.LPCB.EC0.KBLV)
}
}
}
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