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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2015 Google Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
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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