ec: Add support for EC used on Purism Librem laptops

This adds basic ACPI support for the EC used on Purism Librem laptops.
The EC firmware appears to use the topstar laptop interface that has
support in the linux kernel for handling the special keys.

Supported functions:
- Battery information
- AC presence
- Lid switch
- Special keys (after loading topstar-laptop driver in linux)
- EC events for turbo enable/disable when on AC power

Things it does not do:
- EC SMI handling
- Fan is left under EC control

This was developed and tested on a Librem 13 laptop, and has not
been directly tested on an Librem 15.

Change-Id: Ib85a24e4cc8ab09b14147060043cff372863c2d1
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/13025
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/src/ec/purism/librem/acpi/ac.asl b/src/ec/purism/librem/acpi/ac.asl
new file mode 100644
index 0000000000..99d17ee104
--- /dev/null
+++ b/src/ec/purism/librem/acpi/ac.asl
@@ -0,0 +1,30 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 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.
+ */
+
+Device (AC)
+{
+	Name (_HID, "ACPI0003")
+	Name (_PCL, Package () { \_SB })
+
+	Method (_PSR)
+	{
+		Return (ACEX)
+	}
+
+	Method (_STA)
+	{
+		Return (0x0F)
+	}
+}