lantiq: add device tree binding for the phy clock source

Signed-off-by: Mathias Kresin <openwrt@kresin.me>

SVN-Revision: 49283

target/linux/lantiq/patches-4.4/0301-xrx200-add-gphy-clk-src-device-tree-binding.patch

@@ -0,0 +1,30 @@
+--- a/arch/mips/lantiq/xway/sysctrl.c
++++ b/arch/mips/lantiq/xway/sysctrl.c
+@@ -423,6 +423,20 @@ static void clkdev_add_clkout(void)
+ 	}
+ }
+ 
++static void set_phy_clock_source(struct device_node *np_cgu)
++{
++	u32 phy_clk_src, ifcc;
++
++	if (!np_cgu)
++		return;
++
++	if (of_property_read_u32(np_cgu, "lantiq,phy-clk-src", &phy_clk_src))
++		return;
++
++	ifcc = ltq_cgu_r32(ifccr) & ~(0x1c);
++	ltq_cgu_w32(ifcc | (phy_clk_src << 2), ifccr);
++}
++
+ /* bring up all register ranges that we need for basic system control */
+ void __init ltq_soc_init(void)
+ {
+@@ -608,4 +622,6 @@ void __init ltq_soc_init(void)
+ 
+ 	if (of_machine_is_compatible("lantiq,vr9"))
+ 		xbar_fpi_burst_disable();
++
++	set_phy_clock_source(np_cgu);
+ }