ec/starlabs: Guard Max Charge in Kconfig

Guard Max Charge EC write in Kconfig so it's only used on
platforms that support it.

Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Change-Id: I7be39cd9543c8253d53070950edc6908a21e864a
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62123
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Andy Pont <andy.pont@sdcsystems.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/ec/starlabs/merlin/Kconfig b/src/ec/starlabs/merlin/Kconfig
index 67582ac..93101b7 100644
--- a/src/ec/starlabs/merlin/Kconfig
+++ b/src/ec/starlabs/merlin/Kconfig
@@ -44,6 +44,13 @@
 	help
 	  Select if the mainboard has a fan.
 
+config EC_STARLABS_MAX_CHARGE
+	bool
+	default n
+	depends on EC_STARLABS_ITE
+	help
+	  Select if the mainboard supports limiting the maximum charge of the battery.
+
 config EC_STARLABS_MERLIN
 	bool "Use open-source Merlin EC Firmware"
 	default n
diff --git a/src/ec/starlabs/merlin/ec.c b/src/ec/starlabs/merlin/ec.c
index 40be138..e8eaa22 100644
--- a/src/ec/starlabs/merlin/ec.c
+++ b/src/ec/starlabs/merlin/ec.c
@@ -130,11 +130,12 @@
 		CHARGE_60
 	};
 
-	ec_write(ECRAM_MAX_CHARGE,
-		get_ec_value_from_option("max_charge",
-					 0,
-					 max_charge,
-					 ARRAY_SIZE(max_charge)));
+	if (CONFIG(EC_STARLABS_MAX_CHARGE))
+		ec_write(ECRAM_MAX_CHARGE,
+			get_ec_value_from_option("max_charge",
+						 0,
+						 max_charge,
+						 ARRAY_SIZE(max_charge)));
 
 	/*
 	 * Fan Mode
diff --git a/src/mainboard/starlabs/labtop/Kconfig b/src/mainboard/starlabs/labtop/Kconfig
index 1700fb1..9bf4273 100644
--- a/src/mainboard/starlabs/labtop/Kconfig
+++ b/src/mainboard/starlabs/labtop/Kconfig
@@ -31,6 +31,7 @@
 	select DRIVERS_INTEL_USB4_RETIMER
 	select EC_STARLABS_KBL_LEVELS
 	select EC_STARLABS_FAN
+	select EC_STARLABS_MAX_CHARGE
 	select EC_STARLABS_NEED_ITE_BIN
 	select MAINBOARD_HAS_LPC_TPM
 	select MAINBOARD_HAS_TPM2