phy: rcar-gen3-usb3: add support for R-Car Gen3 USB 3.0 PHY

The USB 3.0 PHY modules of R-Car Gen3 SoCs have:
 - Spread spectrum clock (ssc).
 - Using USB 2.0 EXTAL clock instead of USB 3.0 clock.
 - Enabling VBUS detection for usb3.0 peripheral.

So, this driver supports these features.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

3 files changed, 234 insertions, 0 deletions

diff --git a/drivers/phy/renesas/Kconfig b/drivers/phy/renesas/Kconfig
index 432e2715e9c4..cb09245e9b4c 100644
--- a/drivers/phy/renesas/Kconfig
+++ b/drivers/phy/renesas/Kconfig
@@ -15,3 +15,10 @@ config PHY_RCAR_GEN3_USB2
 	select GENERIC_PHY
 	help
 	  Support for USB 2.0 PHY found on Renesas R-Car generation 3 SoCs.
+
+config PHY_RCAR_GEN3_USB3
+	tristate "Renesas R-Car generation 3 USB 3.0 PHY driver"
+	depends on ARCH_RENESAS || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Support for USB 3.0 PHY found on Renesas R-Car generation 3 SoCs.
diff --git a/drivers/phy/renesas/Makefile b/drivers/phy/renesas/Makefile
index 695241aebf69..8b6025916a93 100644
--- a/drivers/phy/renesas/Makefile
+++ b/drivers/phy/renesas/Makefile
@@ -1,2 +1,3 @@
 obj-$(CONFIG_PHY_RCAR_GEN2)		+= phy-rcar-gen2.o
 obj-$(CONFIG_PHY_RCAR_GEN3_USB2)	+= phy-rcar-gen3-usb2.o
+obj-$(CONFIG_PHY_RCAR_GEN3_USB3)	+= phy-rcar-gen3-usb3.o
diff --git a/drivers/phy/renesas/phy-rcar-gen3-usb3.c b/drivers/phy/renesas/phy-rcar-gen3-usb3.c
new file mode 100644
index 000000000000..88c83c9b8ff9
--- /dev/null
+++ b/drivers/phy/renesas/phy-rcar-gen3-usb3.c
@@ -0,0 +1,226 @@
+/*
+ * Renesas R-Car Gen3 for USB3.0 PHY driver
+ *
+ * Copyright (C) 2017 Renesas Electronics Corporation
+ *
+ * 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/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#define USB30_CLKSET0		0x034
+#define USB30_CLKSET1		0x036
+#define USB30_SSC_SET		0x038
+#define USB30_PHY_ENABLE	0x060
+#define USB30_VBUS_EN		0x064
+
+/* USB30_CLKSET0 */
+#define CLKSET0_PRIVATE			0x05c0
+#define CLKSET0_USB30_FSEL_USB_EXTAL	0x0002
+
+/* USB30_CLKSET1 */
+#define CLKSET1_USB30_PLL_MULTI_SHIFT		6
+#define CLKSET1_USB30_PLL_MULTI_USB_EXTAL	(0x64 << \
+						 CLKSET1_USB30_PLL_MULTI_SHIFT)
+#define CLKSET1_PHYRESET	BIT(4)	/* 1: reset */
+#define CLKSET1_REF_CLKDIV	BIT(3)	/* 1: USB_EXTAL */
+#define CLKSET1_PRIVATE_2_1	BIT(1)	/* Write B'01 */
+#define CLKSET1_REF_CLK_SEL	BIT(0)	/* 1: USB3S0_CLK_P */
+
+/* USB30_SSC_SET */
+#define SSC_SET_SSC_EN		BIT(12)
+#define SSC_SET_RANGE_SHIFT	9
+#define SSC_SET_RANGE_4980	(0x0 << SSC_SET_RANGE_SHIFT)
+#define SSC_SET_RANGE_4492	(0x1 << SSC_SET_RANGE_SHIFT)
+#define SSC_SET_RANGE_4003	(0x2 << SSC_SET_RANGE_SHIFT)
+
+/* USB30_PHY_ENABLE */
+#define PHY_ENABLE_RESET_EN	BIT(4)
+
+/* USB30_VBUS_EN */
+#define VBUS_EN_VBUS_EN		BIT(1)
+
+struct rcar_gen3_usb3 {
+	void __iomem *base;
+	struct phy *phy;
+	u32 ssc_range;
+	bool usb3s_clk;
+	bool usb_extal;
+};
+
+static void write_clkset1_for_usb_extal(struct rcar_gen3_usb3 *r, bool reset)
+{
+	u16 val = CLKSET1_USB30_PLL_MULTI_USB_EXTAL |
+		  CLKSET1_REF_CLKDIV | CLKSET1_PRIVATE_2_1;
+
+	if (reset)
+		val |= CLKSET1_PHYRESET;
+
+	writew(val, r->base + USB30_CLKSET1);
+}
+
+static void rcar_gen3_phy_usb3_enable_ssc(struct rcar_gen3_usb3 *r)
+{
+	u16 val = SSC_SET_SSC_EN;
+
+	switch (r->ssc_range) {
+	case 4980:
+		val |= SSC_SET_RANGE_4980;
+		break;
+	case 4492:
+		val |= SSC_SET_RANGE_4492;
+		break;
+	case 4003:
+		val |= SSC_SET_RANGE_4003;
+		break;
+	default:
+		dev_err(&r->phy->dev, "%s: unsupported range (%x)\n", __func__,
+			r->ssc_range);
+		return;
+	}
+
+	writew(val, r->base + USB30_SSC_SET);
+}
+
+static void rcar_gen3_phy_usb3_select_usb_extal(struct rcar_gen3_usb3 *r)
+{
+	write_clkset1_for_usb_extal(r, false);
+	if (r->ssc_range)
+		rcar_gen3_phy_usb3_enable_ssc(r);
+	writew(CLKSET0_PRIVATE | CLKSET0_USB30_FSEL_USB_EXTAL,
+	       r->base + USB30_CLKSET0);
+	writew(PHY_ENABLE_RESET_EN, r->base + USB30_PHY_ENABLE);
+	write_clkset1_for_usb_extal(r, true);
+	usleep_range(10, 20);
+	write_clkset1_for_usb_extal(r, false);
+}
+
+static int rcar_gen3_phy_usb3_init(struct phy *p)
+{
+	struct rcar_gen3_usb3 *r = phy_get_drvdata(p);
+
+	dev_vdbg(&r->phy->dev, "%s: enter (%d, %d, %d)\n", __func__,
+		 r->usb3s_clk, r->usb_extal, r->ssc_range);
+
+	if (!r->usb3s_clk && r->usb_extal)
+		rcar_gen3_phy_usb3_select_usb_extal(r);
+
+	/* Enables VBUS detection anyway */
+	writew(VBUS_EN_VBUS_EN, r->base + USB30_VBUS_EN);
+
+	return 0;
+}
+
+static const struct phy_ops rcar_gen3_phy_usb3_ops = {
+	.init		= rcar_gen3_phy_usb3_init,
+	.owner		= THIS_MODULE,
+};
+
+static const struct of_device_id rcar_gen3_phy_usb3_match_table[] = {
+	{ .compatible = "renesas,rcar-gen3-usb3-phy" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, rcar_gen3_phy_usb3_match_table);
+
+static int rcar_gen3_phy_usb3_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rcar_gen3_usb3 *r;
+	struct phy_provider *provider;
+	struct resource *res;
+	int ret = 0;
+	struct clk *clk;
+
+	if (!dev->of_node) {
+		dev_err(dev, "This driver needs device tree\n");
+		return -EINVAL;
+	}
+
+	r = devm_kzalloc(dev, sizeof(*r), GFP_KERNEL);
+	if (!r)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	r->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(r->base))
+		return PTR_ERR(r->base);
+
+	clk = devm_clk_get(dev, "usb3s_clk");
+	if (!IS_ERR(clk) && !clk_prepare_enable(clk)) {
+		r->usb3s_clk = !!clk_get_rate(clk);
+		clk_disable_unprepare(clk);
+	}
+	clk = devm_clk_get(dev, "usb_extal");
+	if (!IS_ERR(clk) && !clk_prepare_enable(clk)) {
+		r->usb_extal = !!clk_get_rate(clk);
+		clk_disable_unprepare(clk);
+	}
+
+	if (!r->usb3s_clk && !r->usb_extal) {
+		dev_err(dev, "This driver needs usb3s_clk and/or usb_extal\n");
+		ret = -EINVAL;
+		goto error;
+	}
+
+	/*
+	 * devm_phy_create() will call pm_runtime_enable(&phy->dev);
+	 * And then, phy-core will manage runtime pm for this device.
+	 */
+	pm_runtime_enable(dev);
+
+	r->phy = devm_phy_create(dev, NULL, &rcar_gen3_phy_usb3_ops);
+	if (IS_ERR(r->phy)) {
+		dev_err(dev, "Failed to create USB3 PHY\n");
+		ret = PTR_ERR(r->phy);
+		goto error;
+	}
+
+	of_property_read_u32(dev->of_node, "renesas,ssc-range", &r->ssc_range);
+
+	platform_set_drvdata(pdev, r);
+	phy_set_drvdata(r->phy, r);
+
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(provider)) {
+		dev_err(dev, "Failed to register PHY provider\n");
+		ret = PTR_ERR(provider);
+		goto error;
+	}
+
+	return 0;
+
+error:
+	pm_runtime_disable(dev);
+
+	return ret;
+}
+
+static int rcar_gen3_phy_usb3_remove(struct platform_device *pdev)
+{
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+};
+
+static struct platform_driver rcar_gen3_phy_usb3_driver = {
+	.driver = {
+		.name		= "phy_rcar_gen3_usb3",
+		.of_match_table	= rcar_gen3_phy_usb3_match_table,
+	},
+	.probe	= rcar_gen3_phy_usb3_probe,
+	.remove = rcar_gen3_phy_usb3_remove,
+};
+module_platform_driver(rcar_gen3_phy_usb3_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Renesas R-Car Gen3 USB 3.0 PHY");
+MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>");