usb: phy: add Keystone usb phy driver

Add Keystone platform USB PHY driver support. Current main purpose
of this driver is to enable the PHY reference clock gate on the
Keystone SoC. Otherwise it is a nop PHY.

[ balbi@ti.com : add COMPILE_TEST as a possible dependency
	make sure drvdata is initialized before adding PHY ]

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: WingMan Kwok <w-kwok2@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/phy/Kconfig

@@ -48,6 +48,15 @@ config ISP1301_OMAP
 	  This driver can also be built as a module.  If so, the module
 	  will be called isp1301_omap.
 
+config KEYSTONE_USB_PHY
+	tristate "Keystone USB PHY Driver"
+	depends on ARCH_KEYSTONE || COMPILE_TEST
+	select NOP_USB_XCEIV
+	help
+	  Enable this to support Keystone USB phy. This driver provides
+	  interface to interact with USB 2.0 and USB 3.0 PHY that is part
+	  of the Keystone SOC.
+
 config MV_U3D_PHY
 	bool "Marvell USB 3.0 PHY controller Driver"
 	depends on CPU_MMP3

drivers/usb/phy/Makefile

@@ -32,3 +32,4 @@ obj-$(CONFIG_USB_RCAR_PHY)		+= phy-rcar-usb.o
 obj-$(CONFIG_USB_RCAR_GEN2_PHY)		+= phy-rcar-gen2-usb.o
 obj-$(CONFIG_USB_ULPI)			+= phy-ulpi.o
 obj-$(CONFIG_USB_ULPI_VIEWPORT)		+= phy-ulpi-viewport.o
+obj-$(CONFIG_KEYSTONE_USB_PHY)		+= phy-keystone.o

drivers/usb/phy/phy-keystone.c

+/*
+ * phy-keystone - USB PHY, talking to dwc3 controller in Keystone.
+ *
+ * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Author: WingMan Kwok <w-kwok2@ti.com>
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/usb/usb_phy_gen_xceiv.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+#include "phy-generic.h"
+
+/* USB PHY control register offsets */
+#define USB_PHY_CTL_UTMI		0x0000
+#define USB_PHY_CTL_PIPE		0x0004
+#define USB_PHY_CTL_PARAM_1		0x0008
+#define USB_PHY_CTL_PARAM_2		0x000c
+#define USB_PHY_CTL_CLOCK		0x0010
+#define USB_PHY_CTL_PLL			0x0014
+
+#define PHY_REF_SSP_EN			BIT(29)
+
+struct keystone_usbphy {
+	struct usb_phy_gen_xceiv	usb_phy_gen;
+	void __iomem			*phy_ctrl;
+};
+
+static inline u32 keystone_usbphy_readl(void __iomem *base, u32 offset)
+{
+	return readl(base + offset);
+}
+
+static inline void keystone_usbphy_writel(void __iomem *base,
+					  u32 offset, u32 value)
+{
+	writel(value, base + offset);
+}
+
+static int keystone_usbphy_init(struct usb_phy *phy)
+{
+	struct keystone_usbphy *k_phy = dev_get_drvdata(phy->dev);
+	u32 val;
+
+	val  = keystone_usbphy_readl(k_phy->phy_ctrl, USB_PHY_CTL_CLOCK);
+	keystone_usbphy_writel(k_phy->phy_ctrl, USB_PHY_CTL_CLOCK,
+				val | PHY_REF_SSP_EN);
+	return 0;
+}
+
+static void keystone_usbphy_shutdown(struct usb_phy *phy)
+{
+	struct keystone_usbphy *k_phy = dev_get_drvdata(phy->dev);
+	u32 val;
+
+	val  = keystone_usbphy_readl(k_phy->phy_ctrl, USB_PHY_CTL_CLOCK);
+	keystone_usbphy_writel(k_phy->phy_ctrl, USB_PHY_CTL_CLOCK,
+				val &= ~PHY_REF_SSP_EN);
+}
+
+static int keystone_usbphy_probe(struct platform_device *pdev)
+{
+	struct device		*dev = &pdev->dev;
+	struct keystone_usbphy	*k_phy;
+	struct resource		*res;
+	int ret;
+
+	k_phy = devm_kzalloc(dev, sizeof(*k_phy), GFP_KERNEL);
+	if (!k_phy)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "missing usb phy resource\n");
+		return -EINVAL;
+	}
+
+	k_phy->phy_ctrl = devm_ioremap_resource(dev, res);
+	if (IS_ERR(k_phy->phy_ctrl))
+		return PTR_ERR(k_phy->phy_ctrl);
+
+	ret = usb_phy_gen_create_phy(dev, &k_phy->usb_phy_gen,
+			USB_PHY_TYPE_USB2, 0, false);
+	if (ret)
+		return ret;
+
+	k_phy->usb_phy_gen.phy.init = keystone_usbphy_init;
+	k_phy->usb_phy_gen.phy.shutdown = keystone_usbphy_shutdown;
+
+	platform_set_drvdata(pdev, k_phy);
+
+	ret = usb_add_phy_dev(&k_phy->usb_phy_gen.phy);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int keystone_usbphy_remove(struct platform_device *pdev)
+{
+	struct keystone_usbphy *k_phy = platform_get_drvdata(pdev);
+
+	usb_remove_phy(&k_phy->usb_phy_gen.phy);
+
+	return 0;
+}
+
+static const struct of_device_id keystone_usbphy_ids[] = {
+	{ .compatible = "ti,keystone-usbphy" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, keystone_usbphy_ids);
+
+static struct platform_driver keystone_usbphy_driver = {
+	.probe          = keystone_usbphy_probe,
+	.remove         = keystone_usbphy_remove,
+	.driver         = {
+		.name   = "keystone-usbphy",
+		.owner  = THIS_MODULE,
+		.of_match_table = of_match_ptr(keystone_usbphy_ids),
+	},
+};
+
+module_platform_driver(keystone_usbphy_driver);
+
+MODULE_ALIAS("platform:keystone-usbphy");
+MODULE_AUTHOR("Texas Instruments Inc.");
+MODULE_DESCRIPTION("Keystone USB phy driver");
+MODULE_LICENSE("GPL v2");