IO_Expander: introduce the common interface of IO expander

Implement the common code to provide a friendly interface to control the
IOs of IO expander. It adopts a similar concept to GPIO.

1. Define the IO expander IO in gpio.inc by the format:
    IOEX(name, EXPIN(ioex, port, offset), flags)
    - name: the name of this IO pin
    - EXPIN(ioex, port, offset)
        - ioex: the IO expander port (defined in board.c) this IO
                     pin belongs to.
        - port: the port number in the IO expander chip.
	- offset: the bit offset in the port above.
    - flags: the same as the flags of GPIO.

2. The following APIs are supported:
    1. ioex_get_flags_by_mask
    2. ioex_set_flags_by_mask
    3. ioex_get_flags
    4. ioex_set_flags
    5. ioex_get_level
    6. ioex_set_level
    7. ioex_init

3. The following console commands are supported:
    1. ioexget [IO_EXPANDER_PIN_NAME]
    2. ioexset IO_EXPANDER_PIN_NAME 0/1

BRANCH=none
BUG=none
TEST=No error for "make buildall"
TEST=Apply this and related CLs, manually test each API, make sure each
function works correctly with IO expander chip (NCT3807/NCT3808.)

Change-Id: I79c9813abccc67d5554e2ceb5c119dcf549b7dce
Signed-off-by: CHLin <CHLIN56@nuvoton.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1657858
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>
Commit-Queue: CH Lin <chlin56@nuvoton.com>
Commit-Queue: Aseda Aboagye <aaboagye@chromium.org>
Tested-by: CH Lin <chlin56@nuvoton.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/gpio_signal.h b/include/gpio_signal.h
index 776e84fdae..da34f07b33 100644
--- a/include/gpio_signal.h
+++ b/include/gpio_signal.h
@@ -15,4 +15,11 @@ enum gpio_signal {
 	GPIO_COUNT
 };
 
+#define IOEX(name, expin, flags) IOEX_##name,
+
+enum ioex_signal {
+	#include "gpio.wrap"
+	IOEX_COUNT
+};
+
 #endif /* __CROS_EC_GPIO_SIGNAL_H */