ARM: imx6sl: config iomux-gpr1 to select clock for fec

Config iomux-gpr1 to select clock source for fec system clock.
Clear gpr1[14], gpr1[18-17] bit to select the fec clock source
from internal anatop PLL.

Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

arch/arm/mach-imx/mach-imx6sl.c

@@ -10,16 +10,37 @@
 #include <linux/irqchip.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mfd/syscon/imx6q-iomuxc-gpr.h>
+#include <linux/regmap.h>
 #include <asm/mach/arch.h>
 #include <asm/mach/map.h>
 
 #include "common.h"
 
+static void __init imx6sl_fec_init(void)
+{
+	struct regmap *gpr;
+
+	/* set FEC clock from internal PLL clock source */
+	gpr = syscon_regmap_lookup_by_compatible("fsl,imx6sl-iomuxc-gpr");
+	if (!IS_ERR(gpr)) {
+		regmap_update_bits(gpr, IOMUXC_GPR1,
+			IMX6SL_GPR1_FEC_CLOCK_MUX2_SEL_MASK, 0);
+		regmap_update_bits(gpr, IOMUXC_GPR1,
+			IMX6SL_GPR1_FEC_CLOCK_MUX1_SEL_MASK, 0);
+	} else {
+		pr_err("failed to find fsl,imx6sl-iomux-gpr regmap\n");
+	}
+}
+
 static void __init imx6sl_init_machine(void)
 {
 	mxc_arch_reset_init_dt();
 
 	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
+
+	imx6sl_fec_init();
 }
 
 static void __init imx6sl_init_irq(void)