soc: aspeed: Add LPC mailbox support

The LPC mailbox controller consists of multiple general
registers for the communication between the Host and the BMC.
The interrupts for data update signaling are also introduced.

Signed-off-by: Chia-Wei Wang <chiawei_wang@aspeedtech.com>

drivers/soc/aspeed/Kconfig

@@ -24,6 +24,16 @@ config ASPEED_LPC_SNOOP
 	  allows the BMC to listen on and save the data written by
 	  the host to an arbitrary LPC I/O port.
 
+config ASPEED_LPC_MAILBOX
+	tristate "ASPEED LPC mailbox support"
+	select REGMAP
+	select MFD_SYSCON
+	default ARCH_ASPEED
+	help
+	  Provides a driver to control the LPC mailbox which possesses
+	  up to 32 data registers for the communication between the Host
+	  and the BMC over LPC.
+
 config ASPEED_P2A_CTRL
 	tristate "ASPEED P2A (VGA MMIO to BMC) bridge control"
 	select REGMAP

drivers/soc/aspeed/Makefile

@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_ASPEED_LPC_CTRL)	+= aspeed-lpc-ctrl.o
-obj-$(CONFIG_ASPEED_LPC_SNOOP)	+= aspeed-lpc-snoop.o
-obj-$(CONFIG_ASPEED_P2A_CTRL)	+= aspeed-p2a-ctrl.o
-obj-$(CONFIG_ASPEED_SOCINFO)	+= aspeed-socinfo.o
+obj-$(CONFIG_ASPEED_LPC_CTRL)		+= aspeed-lpc-ctrl.o
+obj-$(CONFIG_ASPEED_LPC_SNOOP)		+= aspeed-lpc-snoop.o
+obj-$(CONFIG_ASPEED_LPC_MAILBOX)	+= aspeed-lpc-mbox.o
+obj-$(CONFIG_ASPEED_P2A_CTRL)		+= aspeed-p2a-ctrl.o
+obj-$(CONFIG_ASPEED_SOCINFO)		+= aspeed-socinfo.o