lib: utils/gpio: Use kconfig for enabling/disabling drivers

We update gpio drivers makefile to use kconfig for enabling/disabling
drivers. To avoid compile errors, we also enable appropriate gpio
drivers for each platform.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Tested-by: Andrew Jones <ajones@ventanamicro.com>
Acked-by: Atish Patra <atishp@rivosinc.com>
Tested-by: Atish Patra <atishp@rivosinc.com>

lib/utils/Kconfig

@@ -2,6 +2,8 @@
 
 menu "Utils and Drivers Support"
 
+source "$(OPENSBI_SRC_DIR)/lib/utils/gpio/Kconfig"
+
 source "$(OPENSBI_SRC_DIR)/lib/utils/i2c/Kconfig"
 
 source "$(OPENSBI_SRC_DIR)/lib/utils/ipi/Kconfig"

lib/utils/gpio/Kconfig

@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: BSD-2-Clause
+
+menu "GPIO Support"
+
+config FDT_GPIO
+	bool "FDT based GPIO drivers"
+	select GPIO
+	default n
+
+if FDT_GPIO
+
+config FDT_GPIO_SIFIVE
+	bool "SiFive GPIO FDT driver"
+	default n
+
+endif
+
+config GPIO
+	bool "GPIO support"
+	default n
+
+endmenu

lib/utils/gpio/objects.mk

@@ -7,10 +7,10 @@
 #   Anup Patel <anup.patel@wdc.com>
 #
 
-libsbiutils-objs-y += gpio/fdt_gpio.o
-libsbiutils-objs-y += gpio/fdt_gpio_drivers.o
+libsbiutils-objs-$(CONFIG_FDT_GPIO) += gpio/fdt_gpio.o
+libsbiutils-objs-$(CONFIG_FDT_GPIO) += gpio/fdt_gpio_drivers.o
 
-carray-fdt_gpio_drivers-y += fdt_gpio_sifive
-libsbiutils-objs-y += gpio/fdt_gpio_sifive.o
+carray-fdt_gpio_drivers-$(CONFIG_FDT_GPIO_SIFIVE) += fdt_gpio_sifive
+libsbiutils-objs-$(CONFIG_FDT_GPIO_SIFIVE) += gpio/fdt_gpio_sifive.o
 
-libsbiutils-objs-y += gpio/gpio.o
+libsbiutils-objs-$(CONFIG_GPIO) += gpio/gpio.o

lib/utils/reset/Kconfig

@@ -10,6 +10,7 @@ if FDT_RESET
 
 config FDT_RESET_GPIO
 	bool "GPIO FDT reset driver"
+	depends on FDT_GPIO
 	default n
 
 config FDT_RESET_HTIF

platform/generic/configs/defconfig

@@ -1,3 +1,5 @@
+CONFIG_FDT_GPIO=y
+CONFIG_FDT_GPIO_SIFIVE=y
 CONFIG_FDT_I2C=y
 CONFIG_FDT_I2C_SIFIVE=y
 CONFIG_FDT_IPI=y