stm32f7: use clock driver to enable sdram controller clock

This patch also removes the sdram/fmc clock enable from board specific
code.

Signed-off-by: Vikas Manocha <vikas.manocha@st.com>
cc: Christophe KERELLO <christophe.kerello@st.com>

arch/arm/dts/stm32f746.dtsi

@@ -74,6 +74,7 @@
 		fmc: fmc@A0000000 {
 			compatible = "st,stm32-fmc";
 			reg = <0xA0000000 0x1000>;
+			clocks = <&rcc 0 64>;
 			u-boot,dm-pre-reloc;
 		};
 

board/st/stm32f746-disco/stm32f746-disco.c

@@ -51,8 +51,6 @@ int dram_init(void)
 	if (rv)
 		return rv;
 
-	clock_setup(FMC_CLOCK_CFG);
-
 	rv = uclass_get_device(UCLASS_RAM, 0, &dev);
 	if (rv) {
 		debug("DRAM init failed: %d\n", rv);

drivers/ram/stm32_sdram.c

@@ -6,6 +6,7 @@
  */
 
 #include <common.h>
+#include <clk.h>
 #include <dm.h>
 #include <ram.h>
 #include <asm/io.h>
@@ -122,6 +123,20 @@ int stm32_sdram_init(void)
 
 static int stm32_fmc_probe(struct udevice *dev)
 {
+#ifdef CONFIG_CLK
+	int ret;
+	struct clk clk;
+	ret = clk_get_by_index(dev, 0, &clk);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_enable(&clk);
+
+	if (ret) {
+		dev_err(dev, "failed to enable clock\n");
+		return ret;
+	}
+#endif
 	stm32_sdram_init();
 	return 0;
 }