phy: rcar-gen3-usb2: Add R-Car Gen3 USB2 PHY driver

This patch adds support for R-Car generation 3 USB2 PHY driver.
This SoC has 3 EHCI/OHCI channels, and the channel 0 is shared
with the HSUSB (USB2.0 peripheral) device. And each channel has
independent registers about the PHYs.

So, the purpose of this driver is:
 1) initializes some registers of SoC specific to use the
    {ehci,ohci}-platform driver.

 2) detects id pin to select host or peripheral on the channel 0.

For now, this driver only supports 1) above.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt

@@ -0,0 +1,37 @@
+* Renesas R-Car generation 3 USB 2.0 PHY
+
+This file provides information on what the device node for the R-Car generation
+3 USB 2.0 PHY contains.
+
+Required properties:
+- compatible: "renesas,usb2-phy-r8a7795" if the device is a part of an R8A7795
+	      SoC.
+- reg: offset and length of the partial USB 2.0 Host register block.
+- reg-names: must be "usb2_host".
+- clocks: clock phandle and specifier pair(s).
+- #phy-cells: see phy-bindings.txt in the same directory, must be <0>.
+
+Optional properties:
+To use a USB channel where USB 2.0 Host and HSUSB (USB 2.0 Peripheral) are
+combined, the device tree node should set HSUSB properties to reg and reg-names
+properties. This is because HSUSB has registers to select USB 2.0 host or
+peripheral at that channel:
+- reg: offset and length of the partial HSUSB register block.
+- reg-names: must be "hsusb".
+
+Example (R-Car H3):
+
+	usb-phy@ee080200 {
+		compatible = "renesas,usb2-phy-r8a7795";
+		reg = <0 0xee080200 0 0x700>, <0 0xe6590100 0 0x100>;
+		reg-names = "usb2_host", "hsusb";
+		clocks = <&mstp7_clks R8A7795_CLK_EHCI0>,
+			 <&mstp7_clks R8A7795_CLK_HSUSB>;
+	};
+
+	usb-phy@ee0a0200 {
+		compatible = "renesas,usb2-phy-r8a7795";
+		reg = <0 0xee0a0200 0 0x700>;
+		reg-names = "usb2_host";
+		clocks = <&mstp7_clks R8A7795_CLK_EHCI0>;
+	};

drivers/phy/Kconfig

@@ -118,6 +118,13 @@ config PHY_RCAR_GEN2
 	help
 	  Support for USB PHY found on Renesas R-Car generation 2 SoCs.
 
+config PHY_RCAR_GEN3_USB2
+	tristate "Renesas R-Car generation 3 USB 2.0 PHY driver"
+	depends on OF && ARCH_SHMOBILE
+	select GENERIC_PHY
+	help
+	  Support for USB 2.0 PHY found on Renesas R-Car generation 3 SoCs.
+
 config OMAP_CONTROL_PHY
 	tristate "OMAP CONTROL PHY Driver"
 	depends on ARCH_OMAP2PLUS || COMPILE_TEST

drivers/phy/Makefile

@@ -17,6 +17,7 @@ obj-$(CONFIG_PHY_MVEBU_SATA)		+= phy-mvebu-sata.o
 obj-$(CONFIG_PHY_MIPHY28LP) 		+= phy-miphy28lp.o
 obj-$(CONFIG_PHY_MIPHY365X)		+= phy-miphy365x.o
 obj-$(CONFIG_PHY_RCAR_GEN2)		+= phy-rcar-gen2.o
+obj-$(CONFIG_PHY_RCAR_GEN3_USB2)	+= phy-rcar-gen3-usb2.o
 obj-$(CONFIG_OMAP_CONTROL_PHY)		+= phy-omap-control.o
 obj-$(CONFIG_OMAP_USB2)			+= phy-omap-usb2.o
 obj-$(CONFIG_TI_PIPE3)			+= phy-ti-pipe3.o

drivers/phy/phy-rcar-gen3-usb2.c

@@ -0,0 +1,217 @@
+/*
+ * Renesas R-Car Gen3 for USB2.0 PHY driver
+ *
+ * Copyright (C) 2015 Renesas Electronics Corporation
+ *
+ * This is based on the phy-rcar-gen2 driver:
+ * Copyright (C) 2014 Renesas Solutions Corp.
+ * Copyright (C) 2014 Cogent Embedded, Inc.
+ *
+ * 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/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+
+/******* USB2.0 Host registers (original offset is +0x200) *******/
+#define USB2_INT_ENABLE		0x000
+#define USB2_USBCTR		0x00c
+#define USB2_SPD_RSM_TIMSET	0x10c
+#define USB2_OC_TIMSET		0x110
+
+/* INT_ENABLE */
+#define USB2_INT_ENABLE_USBH_INTB_EN	BIT(2)
+#define USB2_INT_ENABLE_USBH_INTA_EN	BIT(1)
+#define USB2_INT_ENABLE_INIT		(USB2_INT_ENABLE_USBH_INTB_EN | \
+					 USB2_INT_ENABLE_USBH_INTA_EN)
+
+/* USBCTR */
+#define USB2_USBCTR_DIRPD	BIT(2)
+#define USB2_USBCTR_PLL_RST	BIT(1)
+
+/* SPD_RSM_TIMSET */
+#define USB2_SPD_RSM_TIMSET_INIT	0x014e029b
+
+/* OC_TIMSET */
+#define USB2_OC_TIMSET_INIT		0x000209ab
+
+/******* HSUSB registers (original offset is +0x100) *******/
+#define HSUSB_LPSTS			0x02
+#define HSUSB_UGCTRL2			0x84
+
+/* Low Power Status register (LPSTS) */
+#define HSUSB_LPSTS_SUSPM		0x4000
+
+/* USB General control register 2 (UGCTRL2) */
+#define HSUSB_UGCTRL2_MASK		0x00000031 /* bit[31:6] should be 0 */
+#define HSUSB_UGCTRL2_USB0SEL		0x00000030
+#define HSUSB_UGCTRL2_USB0SEL_HOST	0x00000010
+#define HSUSB_UGCTRL2_USB0SEL_HS_USB	0x00000020
+#define HSUSB_UGCTRL2_USB0SEL_OTG	0x00000030
+
+struct rcar_gen3_data {
+	void __iomem *base;
+	struct clk *clk;
+};
+
+struct rcar_gen3_chan {
+	struct rcar_gen3_data usb2;
+	struct rcar_gen3_data hsusb;
+	struct phy *phy;
+};
+
+static int rcar_gen3_phy_usb2_init(struct phy *p)
+{
+	struct rcar_gen3_chan *channel = phy_get_drvdata(p);
+	void __iomem *usb2_base = channel->usb2.base;
+	void __iomem *hsusb_base = channel->hsusb.base;
+	u32 val;
+
+	/* Initialize USB2 part */
+	writel(USB2_INT_ENABLE_INIT, usb2_base + USB2_INT_ENABLE);
+	writel(USB2_SPD_RSM_TIMSET_INIT, usb2_base + USB2_SPD_RSM_TIMSET);
+	writel(USB2_OC_TIMSET_INIT, usb2_base + USB2_OC_TIMSET);
+
+	/* Initialize HSUSB part */
+	if (hsusb_base) {
+		/* TODO: support "OTG" mode */
+		val = readl(hsusb_base + HSUSB_UGCTRL2);
+		val = (val & ~HSUSB_UGCTRL2_USB0SEL) |
+		      HSUSB_UGCTRL2_USB0SEL_HOST;
+		writel(val & HSUSB_UGCTRL2_MASK, hsusb_base + HSUSB_UGCTRL2);
+	}
+
+	return 0;
+}
+
+static int rcar_gen3_phy_usb2_exit(struct phy *p)
+{
+	struct rcar_gen3_chan *channel = phy_get_drvdata(p);
+
+	writel(0, channel->usb2.base + USB2_INT_ENABLE);
+
+	return 0;
+}
+
+static int rcar_gen3_phy_usb2_power_on(struct phy *p)
+{
+	struct rcar_gen3_chan *channel = phy_get_drvdata(p);
+	void __iomem *usb2_base = channel->usb2.base;
+	void __iomem *hsusb_base = channel->hsusb.base;
+	u32 val;
+
+	val = readl(usb2_base + USB2_USBCTR);
+	val |= USB2_USBCTR_PLL_RST;
+	writel(val, usb2_base + USB2_USBCTR);
+	val &= ~USB2_USBCTR_PLL_RST;
+	writel(val, usb2_base + USB2_USBCTR);
+
+	/*
+	 * TODO: To reduce power consuming, this driver should set the SUSPM
+	 *	after the PHY detects ID pin as peripheral.
+	 */
+	if (hsusb_base) {
+		/* Power on HSUSB PHY */
+		val = readw(hsusb_base + HSUSB_LPSTS);
+		val |= HSUSB_LPSTS_SUSPM;
+		writew(val, hsusb_base + HSUSB_LPSTS);
+	}
+
+	return 0;
+}
+
+static int rcar_gen3_phy_usb2_power_off(struct phy *p)
+{
+	struct rcar_gen3_chan *channel = phy_get_drvdata(p);
+	void __iomem *hsusb_base = channel->hsusb.base;
+	u32 val;
+
+	if (hsusb_base) {
+		/* Power off HSUSB PHY */
+		val = readw(hsusb_base + HSUSB_LPSTS);
+		val &= ~HSUSB_LPSTS_SUSPM;
+		writew(val, hsusb_base + HSUSB_LPSTS);
+	}
+
+	return 0;
+}
+
+static struct phy_ops rcar_gen3_phy_usb2_ops = {
+	.init		= rcar_gen3_phy_usb2_init,
+	.exit		= rcar_gen3_phy_usb2_exit,
+	.power_on	= rcar_gen3_phy_usb2_power_on,
+	.power_off	= rcar_gen3_phy_usb2_power_off,
+	.owner		= THIS_MODULE,
+};
+
+static const struct of_device_id rcar_gen3_phy_usb2_match_table[] = {
+	{ .compatible = "renesas,usb2-phy-r8a7795" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, rcar_gen3_phy_usb2_match_table);
+
+static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rcar_gen3_chan *channel;
+	struct phy_provider *provider;
+	struct resource *res;
+
+	if (!dev->of_node) {
+		dev_err(dev, "This driver needs device tree\n");
+		return -EINVAL;
+	}
+
+	channel = devm_kzalloc(dev, sizeof(*channel), GFP_KERNEL);
+	if (!channel)
+		return -ENOMEM;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "usb2_host");
+	channel->usb2.base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(channel->usb2.base))
+		return PTR_ERR(channel->usb2.base);
+
+	/* "hsusb" memory resource is optional */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "hsusb");
+
+	/* To avoid error message by devm_ioremap_resource() */
+	if (res) {
+		channel->hsusb.base = devm_ioremap_resource(dev, res);
+		if (IS_ERR(channel->hsusb.base))
+			channel->hsusb.base = NULL;
+	}
+
+	/* devm_phy_create() will call pm_runtime_enable(dev); */
+	channel->phy = devm_phy_create(dev, NULL, &rcar_gen3_phy_usb2_ops);
+	if (IS_ERR(channel->phy)) {
+		dev_err(dev, "Failed to create USB2 PHY\n");
+		return PTR_ERR(channel->phy);
+	}
+
+	phy_set_drvdata(channel->phy, channel);
+
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(provider))
+		dev_err(dev, "Failed to register PHY provider\n");
+
+	return PTR_ERR_OR_ZERO(provider);
+}
+
+static struct platform_driver rcar_gen3_phy_usb2_driver = {
+	.driver = {
+		.name		= "phy_rcar_gen3_usb2",
+		.of_match_table	= rcar_gen3_phy_usb2_match_table,
+	},
+	.probe	= rcar_gen3_phy_usb2_probe,
+};
+module_platform_driver(rcar_gen3_phy_usb2_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Renesas R-Car Gen3 USB 2.0 PHY");
+MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");