clk: Add GPIO-controlled clock gate driver

Add driver which implements GPIO-controlled clock. The GPIO is used
as a gate to enable/disable the clock. This matches linux clk-gpio.c
driver, however this does not implement the GPIO mux part, which in
U-Boot DM would be better fit in separate driver.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
diff --git a/drivers/clk/Kconfig b/drivers/clk/Kconfig
index 29859cd..bfd23a9 100644
--- a/drivers/clk/Kconfig
+++ b/drivers/clk/Kconfig
@@ -83,6 +83,19 @@
 	  Enable this option if you want to (re-)use the Linux kernel's Common
 	  Clock Framework [CCF] composite code in U-Boot's clock driver.
 
+config CLK_GPIO
+	bool "GPIO-controlled clock gate driver"
+	depends on CLK
+	help
+	  Enable this option to add GPIO-controlled clock gate driver.
+
+config SPL_CLK_GPIO
+	bool "GPIO-controlled clock gate driver in SPL"
+	depends on SPL_CLK
+	help
+	  Enable this option to add GPIO-controlled clock gate driver
+	  in U-Boot SPL.
+
 config CLK_BCM6345
 	bool "Clock controller driver for BCM6345"
 	depends on CLK && ARCH_BMIPS