[coreboot-gerrit] Change in coreboot[master]: ec/kontron/kempld: Add minimal GPIO driver

[Maxim Polyakov (Code Review)]

Attention is currently required from: Angel Pons.
Hello  Felix Singer, build bot (Jenkins), Nico Huber, Patrick Georgi, Martin Roth, Angel Pons, Werner Zeh,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/47595

to look at the new patch set (#10).

Change subject: ec/kontron/kempld: Add minimal GPIO driver
......................................................................

ec/kontron/kempld: Add minimal GPIO driver

The patch adds an interface for configuring GPIOs inside the Kontron
CPLD/EC. This allows to statically define the mode for each pad in
devicetree.cb of the motherboard or carrier board. For example:

chip ec/kontron/kempld
    device gpio 0 on
    	register "gpio[0]"  = "KEMPLD_GPIO_INPUT"
    	register "gpio[4]"  = "KEMPLD_GPIO_OUTPUT_LOW"
    	register "gpio[5]"  = "KEMPLD_GPIO_OUTPUT_HIGH"
    	register "gpio[11]" = "KEMPLD_GPIO_DEFAULT"
    end
end

In this case, <device gpio 0>, like all other devices, is not a real
device inside the EC. These definitions are used to understand the EC
resources and systematize configuration options, but if mark this as
<off>, the initialization step will be skipped in the driver code.

Use KEMPLD_GPIO_DEFAULT or skip it in devicetree.cb to not configure
the pad and keep the default mode after CPLD reset.

This work is based on code from the drivers/gpio/gpio-kempld.c linux
driver. Tested on Kontron mAL-10 COMe module CB:54380 .

Change-Id: Id767aa451fbf2ca1c0dccfc9aa2c024c6f37c1bb
Signed-off-by: Maxim Polyakov 
---
M src/ec/kontron/kempld/Makefile.inc
M src/ec/kontron/kempld/chip.h
M src/ec/kontron/kempld/kempld.c
A src/ec/kontron/kempld/kempld_gpio.c
M src/ec/kontron/kempld/kempld_internal.h
5 files changed, 95 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/95/47595/10