ARM: OMAP4: USB: power down MUSB PHY during boot

Commit c9e4412ab8eb8ef82d645d8749c4ce96ad490007 removed all of the USB
PHY functions for OMAP4, but this causes a problem with core retention
as the MUSB module remains enabled if omap-usb2 phy driver is not used.
This keeps the USB DPLL enabled and prevents l3_init pwrdm from idling.

Fixed by adding a minimal function back that disables the USB PHY during
boot.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

arch/arm/mach-omap2/omap_phy_internal.c

@@ -33,6 +33,38 @@
 #include "soc.h"
 #include "control.h"
 
+#define CONTROL_DEV_CONF		0x300
+#define PHY_PD				0x1
+
+/**
+ * omap4430_phy_power_down: disable MUSB PHY during early init
+ *
+ * OMAP4 MUSB PHY module is enabled by default on reset, but this will
+ * prevent core retention if not disabled by SW. USB driver will
+ * later on enable this, once and if the driver needs it.
+ */
+static int __init omap4430_phy_power_down(void)
+{
+	void __iomem *ctrl_base;
+
+	if (!cpu_is_omap44xx())
+		return 0;
+
+	ctrl_base = ioremap(OMAP443X_SCM_BASE, SZ_1K);
+	if (!ctrl_base) {
+		pr_err("control module ioremap failed\n");
+		return -ENOMEM;
+	}
+
+	/* Power down the phy */
+	__raw_writel(PHY_PD, ctrl_base + CONTROL_DEV_CONF);
+
+	iounmap(ctrl_base);
+
+	return 0;
+}
+early_initcall(omap4430_phy_power_down);
+
 void am35x_musb_reset(void)
 {
 	u32	regval;