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, 36 insertions, 0 deletions

diff --git a/include/gpio_list.h b/include/gpio_list.h
index 70d7bfc4b2..4fed0d60d6 100644
--- a/include/gpio_list.h
+++ b/include/gpio_list.h
@@ -52,3 +52,39 @@ const int gpio_ih_count = ARRAY_SIZE(gpio_irq_handlers);
 #define PIN(a, b...) static const int _pin_ ## a ## _ ## b \
 	__attribute__((unused, section(".unused"))) = __LINE__;
 #include "gpio.wrap"
+
+#include "ioexpander.h"
+/*
+ *  Define the IO expander IO in gpio.inc by the format:
+ *    IOEX(name, EXPIN(ioex_port, 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.
+ *
+ */
+#define IOEX_EXPIN(ioex, port, index) (ioex), (port), BIT(index)
+
+#define IOEX(name, expin, flags) {#name, IOEX_##expin, flags},
+
+/* IO expander signal list. */
+const struct ioex_info ioex_list[] = {
+	#include "gpio.wrap"
+};
+BUILD_ASSERT(ARRAY_SIZE(ioex_list) == IOEX_COUNT);
+
+#define IOEX(name, expin, flags) expin
+
+/* The compiler will complain if we use the same name twice or the controller
+ * number declared is greater or equal to CONFIG_IO_EXPANDER_PORT_COUNT.
+ * The linker ignores anything that gets by.
+ */
+#define EXPIN(a, b, c...) \
+	static const int _expin_ ## a ## _ ## b ## _ ## c \
+	__attribute__((unused, section(".unused"))) = __LINE__; \
+	BUILD_ASSERT(a < CONFIG_IO_EXPANDER_PORT_COUNT);
+
+#include "gpio.wrap"