treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

Based on 1 normalized pattern(s):

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

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tools/power/acpi: Enable build for EC userspace tool

This patch allows EC userspace tool to be built as an ACPI tool.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI / tools: Introduce ec_access.c - tool to access the EC

This userspace tool accesses the EC through the ec_sys debug driver
(through /sys/kernel/debug/ec/ec0/io).

The EC command/data registers cannot be accessed directly, because they
may be manipulated by the AML interpreter in parallel.

The ec_sys driver synchronizes user space (debug) access with the AML
interpreter.

Signed-off-by: Thomas Renninger <trenn@suse.de>
[rjw: Changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>