firmware: arm_scmi: Add initial support for i.MX BBM protocol

i.MX95 has a battery-backed module(BBM), which has persistent storage
(GPR), an RTC, and the ON/OFF button. The System Manager(SM) firmware
use SCMI vendor protocol(SCMI BBM) to let agent be able to use GPR, RTC
and ON/OFF button.

Reviewed-by: Cristian Marussi <[email protected]>
Signed-off-by: Peng Fan <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Sudeep Holla <[email protected]>

Author: MrVan

drivers/firmware/arm_scmi/Kconfig

@@ -70,6 +70,7 @@ config ARM_SCMI_DEBUG_COUNTERS
 	  SCMI monitoring.
 
 source "drivers/firmware/arm_scmi/transports/Kconfig"
+source "drivers/firmware/arm_scmi/vendors/imx/Kconfig"
 
 endif #ARM_SCMI_PROTOCOL
 

drivers/firmware/arm_scmi/Makefile

@@ -11,6 +11,7 @@ scmi-protocols-y += pinctrl.o
 scmi-module-objs := $(scmi-driver-y) $(scmi-protocols-y) $(scmi-transport-y)
 
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += transports/
+obj-$(CONFIG_ARM_SCMI_PROTOCOL) += vendors/imx/
 
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-core.o
 obj-$(CONFIG_ARM_SCMI_PROTOCOL) += scmi-module.o

drivers/firmware/arm_scmi/vendors/imx/Kconfig

@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "ARM SCMI NXP i.MX Vendor Protocols"
+
+config IMX_SCMI_BBM_EXT
+	tristate "i.MX SCMI BBM EXTENSION"
+	depends on ARM_SCMI_PROTOCOL || (COMPILE_TEST && OF)
+	default y if ARCH_MXC
+	help
+	  This enables i.MX System BBM control logic which supports RTC
+	  and BUTTON.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called imx-sm-bbm.
+
+endmenu

drivers/firmware/arm_scmi/vendors/imx/Makefile

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_IMX_SCMI_BBM_EXT) += imx-sm-bbm.o