usb: dwc3: add ULPI interface support

Registers DWC3's ULPI interface with the ULPI bus when it's
available.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: David Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/Kconfig

@@ -11,6 +11,13 @@ config USB_DWC3
 
 if USB_DWC3
 
+config USB_DWC3_ULPI
+	bool "Register ULPI PHY Interface"
+	depends on USB_ULPI_BUS=y || USB_ULPI_BUS=USB_DWC3
+	help
+	  Select this if you have ULPI type PHY attached to your DWC3
+	  controller.
+
 choice
 	bool "DWC3 Mode Selection"
 	default USB_DWC3_DUAL_ROLE if (USB && USB_GADGET)

drivers/usb/dwc3/Makefile

@@ -15,6 +15,10 @@ ifneq ($(filter y,$(CONFIG_USB_DWC3_GADGET) $(CONFIG_USB_DWC3_DUAL_ROLE)),)
 	dwc3-y				+= gadget.o ep0.o
 endif
 
+ifneq ($(CONFIG_USB_DWC3_ULPI),)
+	dwc3-y				+= ulpi.o
+endif
+
 ifneq ($(CONFIG_DEBUG_FS),)
 	dwc3-y				+= debugfs.o
 endif

drivers/usb/dwc3/core.c

@@ -394,10 +394,15 @@ static void dwc3_cache_hwparams(struct dwc3 *dwc)
 /**
  * dwc3_phy_setup - Configure USB PHY Interface of DWC3 Core
  * @dwc: Pointer to our controller context structure
+ *
+ * Returns 0 on success. The USB PHY interfaces are configured but not
+ * initialized. The PHY interfaces and the PHYs get initialized together with
+ * the core in dwc3_core_init.
  */
-static void dwc3_phy_setup(struct dwc3 *dwc)
+static int dwc3_phy_setup(struct dwc3 *dwc)
 {
 	u32 reg;
+	int ret;
 
 	reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
 
@@ -443,13 +448,30 @@ static void dwc3_phy_setup(struct dwc3 *dwc)
 	case DWC3_GHWPARAMS3_HSPHY_IFC_UTMI_ULPI:
 		if (!strncmp(dwc->hsphy_interface, "utmi", 4)) {
 			reg &= ~DWC3_GUSB2PHYCFG_ULPI_UTMI;
+			break;
 		} else if (!strncmp(dwc->hsphy_interface, "ulpi", 4)) {
 			reg |= DWC3_GUSB2PHYCFG_ULPI_UTMI;
+			dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
 		} else {
 			dev_warn(dwc->dev, "HSPHY Interface not defined\n");
-			break;
+
+			/* Relying on default value. */
+			if (!(reg & DWC3_GUSB2PHYCFG_ULPI_UTMI))
+				break;
 		}
 		/* FALLTHROUGH */
+	case DWC3_GHWPARAMS3_HSPHY_IFC_ULPI:
+		/* Making sure the interface and PHY are operational */
+		ret = dwc3_soft_reset(dwc);
+		if (ret)
+			return ret;
+
+		udelay(1);
+
+		ret = dwc3_ulpi_init(dwc);
+		if (ret)
+			return ret;
+		/* FALLTHROUGH */
 	default:
 		break;
 	}
@@ -467,6 +489,8 @@ static void dwc3_phy_setup(struct dwc3 *dwc)
 		reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
 
 	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+
+	return 0;
 }
 
 /**
@@ -906,7 +930,9 @@ static int dwc3_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, dwc);
 	dwc3_cache_hwparams(dwc);
 
-	dwc3_phy_setup(dwc);
+	ret = dwc3_phy_setup(dwc);
+	if (ret)
+		goto err0;
 
 	ret = dwc3_core_get_phy(dwc);
 	if (ret)
@@ -994,6 +1020,7 @@ err2:
 
 err1:
 	dwc3_free_event_buffers(dwc);
+	dwc3_ulpi_exit(dwc);
 
 err0:
 	/*
@@ -1029,6 +1056,7 @@ static int dwc3_remove(struct platform_device *pdev)
 	phy_power_off(dwc->usb3_generic_phy);
 
 	dwc3_core_exit(dwc);
+	dwc3_ulpi_exit(dwc);
 
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);

drivers/usb/dwc3/core.h

@@ -30,6 +30,7 @@
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
 #include <linux/usb/otg.h>
+#include <linux/ulpi/interface.h>
 
 #include <linux/phy/phy.h>
 
@@ -661,6 +662,7 @@ struct dwc3_scratchpad_array {
  * @usb3_phy: pointer to USB3 PHY
  * @usb2_generic_phy: pointer to USB2 PHY
  * @usb3_generic_phy: pointer to USB3 PHY
+ * @ulpi: pointer to ulpi interface
  * @dcfg: saved contents of DCFG register
  * @gctl: saved contents of GCTL register
  * @isoch_delay: wValue from Set Isochronous Delay request;
@@ -749,6 +751,8 @@ struct dwc3 {
 	struct phy		*usb2_generic_phy;
 	struct phy		*usb3_generic_phy;
 
+	struct ulpi		*ulpi;
+
 	void __iomem		*regs;
 	size_t			regs_size;
 
@@ -1047,4 +1051,14 @@ static inline int dwc3_gadget_resume(struct dwc3 *dwc)
 }
 #endif /* !IS_ENABLED(CONFIG_USB_DWC3_HOST) */
 
+#if IS_ENABLED(CONFIG_USB_DWC3_ULPI)
+int dwc3_ulpi_init(struct dwc3 *dwc);
+void dwc3_ulpi_exit(struct dwc3 *dwc);
+#else
+static inline int dwc3_ulpi_init(struct dwc3 *dwc)
+{ return 0; }
+static inline void dwc3_ulpi_exit(struct dwc3 *dwc)
+{ }
+#endif
+
 #endif /* __DRIVERS_USB_DWC3_CORE_H */

drivers/usb/dwc3/ulpi.c

@@ -0,0 +1,91 @@
+/**
+ * ulpi.c - DesignWare USB3 Controller's ULPI PHY interface
+ *
+ * Copyright (C) 2015 Intel Corporation
+ *
+ * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/ulpi/regs.h>
+
+#include "core.h"
+#include "io.h"
+
+#define DWC3_ULPI_ADDR(a) \
+		((a >= ULPI_EXT_VENDOR_SPECIFIC) ? \
+		DWC3_GUSB2PHYACC_ADDR(ULPI_ACCESS_EXTENDED) | \
+		DWC3_GUSB2PHYACC_EXTEND_ADDR(a) : DWC3_GUSB2PHYACC_ADDR(a))
+
+static int dwc3_ulpi_busyloop(struct dwc3 *dwc)
+{
+	unsigned count = 1000;
+	u32 reg;
+
+	while (count--) {
+		reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
+		if (!(reg & DWC3_GUSB2PHYACC_BUSY))
+			return 0;
+		cpu_relax();
+	}
+
+	return -ETIMEDOUT;
+}
+
+static int dwc3_ulpi_read(struct ulpi_ops *ops, u8 addr)
+{
+	struct dwc3 *dwc = dev_get_drvdata(ops->dev);
+	u32 reg;
+	int ret;
+
+	reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
+	dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg);
+
+	ret = dwc3_ulpi_busyloop(dwc);
+	if (ret)
+		return ret;
+
+	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
+
+	return DWC3_GUSB2PHYACC_DATA(reg);
+}
+
+static int dwc3_ulpi_write(struct ulpi_ops *ops, u8 addr, u8 val)
+{
+	struct dwc3 *dwc = dev_get_drvdata(ops->dev);
+	u32 reg;
+
+	reg = DWC3_GUSB2PHYACC_NEWREGREQ | DWC3_ULPI_ADDR(addr);
+	reg |= DWC3_GUSB2PHYACC_WRITE | val;
+	dwc3_writel(dwc->regs, DWC3_GUSB2PHYACC(0), reg);
+
+	return dwc3_ulpi_busyloop(dwc);
+}
+
+static struct ulpi_ops dwc3_ulpi_ops = {
+	.read = dwc3_ulpi_read,
+	.write = dwc3_ulpi_write,
+};
+
+int dwc3_ulpi_init(struct dwc3 *dwc)
+{
+	/* Register the interface */
+	dwc->ulpi = ulpi_register_interface(dwc->dev, &dwc3_ulpi_ops);
+	if (IS_ERR(dwc->ulpi)) {
+		dev_err(dwc->dev, "failed to register ULPI interface");
+		return PTR_ERR(dwc->ulpi);
+	}
+
+	return 0;
+}
+
+void dwc3_ulpi_exit(struct dwc3 *dwc)
+{
+	if (dwc->ulpi) {
+		ulpi_unregister_interface(dwc->ulpi);
+		dwc->ulpi = NULL;
+	}
+}