ec/clevo/it5570e: add driver for EC used on various Clevo laptops

This adds a driver for the ITE IT5570E EC in combination with Clevo
vendor EC firmware. The interface is mostly identical on various laptop
models. Thus, we have implemented one common driver to support them all.

The following features were implemented:
 - Basics like battery, ac, etc.
 - Suspend/hibernate support: S0ix, S3*, S4/S5
 - Save/restore of keyboard backlight level during S0ix without the need
   for Clevo vendor software (ControlCenter)
 - Flexicharger
 - Fn keys (backlight, volume, airplane etc.)
 - Various configuration options via Kconfig / CMOS options

* Note: S3 support works at least on L140CU (Cometlake), but it's not
        enabled for this board because S0ix is used.

Not implemented, yet:
 - Type-C UCSI: the EC firmware seems to be buggy (with vendor fw, too)
 - dGPU support is WIP

An example of how this driver can be hooked up by a board can be seen in
in change CB:59850, where support for the L140MU is added.

Known issues:

 - Touchpad toggle:
   The touchpad toggle (Fn-F1) has two modes, Ctrl-Alt-F9 mode and
   keycodes 0xf7/0xf8 mode. Ctrl-Alt-F9 is the native touchpad toggle
   shortcut on Windows. On Linux this would switch to virtual console 9,
   if enabled.  Thus, one should use the keycodes mode and add udev
   rules as specified in [1]. If VT9 is disabled, Ctrl-Alt-F9 mode could
   be used to set up a keyboard shortcut command toggling the touchpad.

 - Multi-fan systems
   The Clevo NV41MZ (w/o dGPU) has two fans that should be in-sync.
   However, the second fan does not spin. This needs further
   investigation.

[1] https://docs.dasharo.com/variants/clevo_nv41/post_install/

Testing the various functionalities of this EC driver was done in the
changes hooking up this driver for the boards.

Change-Id: Ic8c0bee9002ad9edcd10c83b775fc723744caaa0
Co-authored-by: Michał Kopeć <michal.kopec@3mdeb.com>
Co-authored-by: Michał Żygowski <michal.zygowski@3mdeb.com>
Co-authored-by: Michael Niewöhner <foss@mniewoehner.de>
Signed-off-by: Michał Kopeć <michal.kopec@3mdeb.com>
Signed-off-by: Michał Żygowski <michal.zygowski@3mdeb.com>
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/68791
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/ec/clevo/it5570e/acpi/buttons.asl b/src/ec/clevo/it5570e/acpi/buttons.asl
new file mode 100644
index 0000000000..3f5dd12973
--- /dev/null
+++ b/src/ec/clevo/it5570e/acpi/buttons.asl
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+Device (PWRB)
+{
+	Name (_HID, "PNP0C0C")
+	Name (_PRW, Package () { EC_GPE_PWRB, 4 })
+}
+
+Device (SLPB)
+{
+	Name (_HID, "PNP0C0E")
+	Name (_PRW, Package () { EC_GPE_SLPB, 3 })
+}