samsung: usb: phy: Support for DWC3 PHY

New files, namely samsung_usb_phy.c and samsung-usb-phy-uboot.h have
been added to u-boot to provide proper PHY handling at Exynos5 SoCs.

This code is used thereafter in the board_usb_init() call.

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Cc: Minkyu Kang <mk7.kang@samsung.com>
Cc: Marek Vasut <marex@denx.de>

drivers/usb/dwc3/Makefile

@@ -6,3 +6,4 @@ dwc3-y					+= gadget.o ep0.o
 
 obj-$(CONFIG_USB_DWC3_OMAP)		+= dwc3-omap.o
 obj-$(CONFIG_USB_DWC3_PHY_OMAP)		+= ti_usb_phy.o
+obj-$(CONFIG_USB_DWC3_PHY_SAMSUNG)	+= samsung_usb_phy.o

drivers/usb/dwc3/samsung_usb_phy.c

@@ -0,0 +1,78 @@
+/**
+ * samsung_usb_phy.c - DesignWare USB3 (DWC3) PHY handling file
+ *
+ * Copyright (C) 2015 Samsung Electronics
+ *
+ * Author: Joonyoung Shim <jy0922.shim@samsung.com>
+ *
+ * SPDX-License-Identifier:     GPL-2.0
+ */
+
+#include <common.h>
+#include <asm/arch/power.h>
+#include <asm/arch/xhci-exynos.h>
+
+void exynos5_usb3_phy_init(struct exynos_usb3_phy *phy)
+{
+	u32 reg;
+
+	/* Reset USB 3.0 PHY */
+	writel(0x0, &phy->phy_reg0);
+
+	clrbits_le32(&phy->phy_param0,
+			/* Select PHY CLK source */
+			PHYPARAM0_REF_USE_PAD |
+			/* Set Loss-of-Signal Detector sensitivity */
+			PHYPARAM0_REF_LOSLEVEL_MASK);
+	setbits_le32(&phy->phy_param0, PHYPARAM0_REF_LOSLEVEL);
+
+
+	writel(0x0, &phy->phy_resume);
+
+	/*
+	 * Setting the Frame length Adj value[6:1] to default 0x20
+	 * See xHCI 1.0 spec, 5.2.4
+	 */
+	setbits_le32(&phy->link_system,
+			LINKSYSTEM_XHCI_VERSION_CONTROL |
+			LINKSYSTEM_FLADJ(0x20));
+
+	/* Set Tx De-Emphasis level */
+	clrbits_le32(&phy->phy_param1, PHYPARAM1_PCS_TXDEEMPH_MASK);
+	setbits_le32(&phy->phy_param1, PHYPARAM1_PCS_TXDEEMPH);
+
+	setbits_le32(&phy->phy_batchg, PHYBATCHG_UTMI_CLKSEL);
+
+	/* PHYTEST POWERDOWN Control */
+	clrbits_le32(&phy->phy_test,
+			PHYTEST_POWERDOWN_SSP |
+			PHYTEST_POWERDOWN_HSP);
+
+	/* UTMI Power Control */
+	writel(PHYUTMI_OTGDISABLE, &phy->phy_utmi);
+
+		/* Use core clock from main PLL */
+	reg = PHYCLKRST_REFCLKSEL_EXT_REFCLK |
+		/* Default 24Mhz crystal clock */
+		PHYCLKRST_FSEL(FSEL_CLKSEL_24M) |
+		PHYCLKRST_MPLL_MULTIPLIER_24MHZ_REF |
+		PHYCLKRST_SSC_REFCLKSEL(0) |
+		/* Force PortReset of PHY */
+		PHYCLKRST_PORTRESET |
+		/* Digital power supply in normal operating mode */
+		PHYCLKRST_RETENABLEN |
+		/* Enable ref clock for SS function */
+		PHYCLKRST_REF_SSP_EN |
+		/* Enable spread spectrum */
+		PHYCLKRST_SSC_EN |
+		/* Power down HS Bias and PLL blocks in suspend mode */
+		PHYCLKRST_COMMONONN;
+
+	writel(reg, &phy->phy_clk_rst);
+
+	/* giving time to Phy clock to settle before resetting */
+	udelay(10);
+
+	reg &= ~PHYCLKRST_PORTRESET;
+	writel(reg, &phy->phy_clk_rst);
+}

include/samsung-usb-phy-uboot.h

@@ -0,0 +1,16 @@
+/* include/samsung-usb-phy-uboot.h
+ *
+ * Copyright (c) 2015 Samsung Electronics
+ *
+ * USB3 (DWC3) PHY uboot init
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#ifndef __SAMSUNG_USB_PHY_UBOOT_H_
+#define __SAMSUNG_USB_PHY_UBOOT_H_
+
+#include <asm/arch/xhci-exynos.h>
+
+void exynos5_usb3_phy_init(struct exynos_usb3_phy *phy);
+#endif /* __SAMSUNG_USB_PHY_UBOOT_H_ */