phy: socionext: add PCIe PHY driver support

Add a driver for PHY interface built into PCIe controller implemented
in UniPhier SoCs.
Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/socionext/Kconfig

@@ -23,3 +23,12 @@ config PHY_UNIPHIER_USB3
 	help
 	  Enable this to support USB PHY implemented in USB3 controller
 	  on UniPhier SoCs. This controller supports USB3.0 and lower speed.
+
+config PHY_UNIPHIER_PCIE
+	tristate "Uniphier PHY driver for PCIe controller"
+	depends on (ARCH_UNIPHIER || COMPILE_TEST) && OF
+	default PCIE_UNIPHIER
+	select GENERIC_PHY
+	help
+	  Enable this to support PHY implemented in PCIe controller
+	  on UniPhier SoCs. This driver supports LD20 and PXs3 SoCs.

drivers/phy/socionext/Makefile

@@ -5,3 +5,4 @@
 
 obj-$(CONFIG_PHY_UNIPHIER_USB2)	+= phy-uniphier-usb2.o
 obj-$(CONFIG_PHY_UNIPHIER_USB3)	+= phy-uniphier-usb3hs.o phy-uniphier-usb3ss.o
+obj-$(CONFIG_PHY_UNIPHIER_PCIE)	+= phy-uniphier-pcie.o

drivers/phy/socionext/phy-uniphier-pcie.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * phy-uniphier-pcie.c - PHY driver for UniPhier PCIe controller
+ * Copyright 2018, Socionext Inc.
+ * Author: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/iopoll.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/resource.h>
+
+/* PHY */
+#define PCL_PHY_TEST_I		0x2000
+#define PCL_PHY_TEST_O		0x2004
+#define TESTI_DAT_MASK		GENMASK(13, 6)
+#define TESTI_ADR_MASK		GENMASK(5, 1)
+#define TESTI_WR_EN		BIT(0)
+
+#define PCL_PHY_RESET		0x200c
+#define PCL_PHY_RESET_N_MNMODE	BIT(8)	/* =1:manual */
+#define PCL_PHY_RESET_N		BIT(0)	/* =1:deasssert */
+
+/* SG */
+#define SG_USBPCIESEL		0x590
+#define SG_USBPCIESEL_PCIE	BIT(0)
+
+#define PCL_PHY_R00		0
+#define   RX_EQ_ADJ_EN		BIT(3)		/* enable for EQ adjustment */
+#define PCL_PHY_R06		6
+#define   RX_EQ_ADJ		GENMASK(5, 0)	/* EQ adjustment value */
+#define   RX_EQ_ADJ_VAL		0
+#define PCL_PHY_R26		26
+#define   VCO_CTRL		GENMASK(7, 4)	/* Tx VCO adjustment value */
+#define   VCO_CTRL_INIT_VAL	5
+
+struct uniphier_pciephy_priv {
+	void __iomem *base;
+	struct device *dev;
+	struct clk *clk;
+	struct reset_control *rst;
+	const struct uniphier_pciephy_soc_data *data;
+};
+
+struct uniphier_pciephy_soc_data {
+	bool has_syscon;
+};
+
+static void uniphier_pciephy_testio_write(struct uniphier_pciephy_priv *priv,
+					  u32 data)
+{
+	/* need to read TESTO twice after accessing TESTI */
+	writel(data, priv->base + PCL_PHY_TEST_I);
+	readl(priv->base + PCL_PHY_TEST_O);
+	readl(priv->base + PCL_PHY_TEST_O);
+}
+
+static void uniphier_pciephy_set_param(struct uniphier_pciephy_priv *priv,
+				       u32 reg, u32 mask, u32 param)
+{
+	u32 val;
+
+	/* read previous data */
+	val  = FIELD_PREP(TESTI_DAT_MASK, 1);
+	val |= FIELD_PREP(TESTI_ADR_MASK, reg);
+	uniphier_pciephy_testio_write(priv, val);
+	val = readl(priv->base + PCL_PHY_TEST_O);
+
+	/* update value */
+	val &= ~FIELD_PREP(TESTI_DAT_MASK, mask);
+	val  = FIELD_PREP(TESTI_DAT_MASK, mask & param);
+	val |= FIELD_PREP(TESTI_ADR_MASK, reg);
+	uniphier_pciephy_testio_write(priv, val);
+	uniphier_pciephy_testio_write(priv, val | TESTI_WR_EN);
+	uniphier_pciephy_testio_write(priv, val);
+
+	/* read current data as dummy */
+	val  = FIELD_PREP(TESTI_DAT_MASK, 1);
+	val |= FIELD_PREP(TESTI_ADR_MASK, reg);
+	uniphier_pciephy_testio_write(priv, val);
+	readl(priv->base + PCL_PHY_TEST_O);
+}
+
+static void uniphier_pciephy_assert(struct uniphier_pciephy_priv *priv)
+{
+	u32 val;
+
+	val = readl(priv->base + PCL_PHY_RESET);
+	val &= ~PCL_PHY_RESET_N;
+	val |= PCL_PHY_RESET_N_MNMODE;
+	writel(val, priv->base + PCL_PHY_RESET);
+}
+
+static void uniphier_pciephy_deassert(struct uniphier_pciephy_priv *priv)
+{
+	u32 val;
+
+	val = readl(priv->base + PCL_PHY_RESET);
+	val |= PCL_PHY_RESET_N_MNMODE | PCL_PHY_RESET_N;
+	writel(val, priv->base + PCL_PHY_RESET);
+}
+
+static int uniphier_pciephy_init(struct phy *phy)
+{
+	struct uniphier_pciephy_priv *priv = phy_get_drvdata(phy);
+	int ret;
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		return ret;
+
+	ret = reset_control_deassert(priv->rst);
+	if (ret)
+		goto out_clk_disable;
+
+	uniphier_pciephy_set_param(priv, PCL_PHY_R00,
+				   RX_EQ_ADJ_EN, RX_EQ_ADJ_EN);
+	uniphier_pciephy_set_param(priv, PCL_PHY_R06, RX_EQ_ADJ,
+				   FIELD_PREP(RX_EQ_ADJ, RX_EQ_ADJ_VAL));
+	uniphier_pciephy_set_param(priv, PCL_PHY_R26, VCO_CTRL,
+				   FIELD_PREP(VCO_CTRL, VCO_CTRL_INIT_VAL));
+	usleep_range(1, 10);
+
+	uniphier_pciephy_deassert(priv);
+	usleep_range(1, 10);
+
+	return 0;
+
+out_clk_disable:
+	clk_disable_unprepare(priv->clk);
+
+	return ret;
+}
+
+static int uniphier_pciephy_exit(struct phy *phy)
+{
+	struct uniphier_pciephy_priv *priv = phy_get_drvdata(phy);
+
+	uniphier_pciephy_assert(priv);
+	reset_control_assert(priv->rst);
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static const struct phy_ops uniphier_pciephy_ops = {
+	.init  = uniphier_pciephy_init,
+	.exit  = uniphier_pciephy_exit,
+	.owner = THIS_MODULE,
+};
+
+static int uniphier_pciephy_probe(struct platform_device *pdev)
+{
+	struct uniphier_pciephy_priv *priv;
+	struct phy_provider *phy_provider;
+	struct device *dev = &pdev->dev;
+	struct regmap *regmap;
+	struct resource *res;
+	struct phy *phy;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->data = of_device_get_match_data(dev);
+	if (WARN_ON(!priv->data))
+		return -EINVAL;
+
+	priv->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	priv->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(priv->base))
+		return PTR_ERR(priv->base);
+
+	priv->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(priv->clk))
+		return PTR_ERR(priv->clk);
+
+	priv->rst = devm_reset_control_get_shared(dev, NULL);
+	if (IS_ERR(priv->rst))
+		return PTR_ERR(priv->rst);
+
+	phy = devm_phy_create(dev, dev->of_node, &uniphier_pciephy_ops);
+	if (IS_ERR(phy))
+		return PTR_ERR(phy);
+
+	regmap = syscon_regmap_lookup_by_phandle(dev->of_node,
+						 "socionext,syscon");
+	if (!IS_ERR(regmap) && priv->data->has_syscon)
+		regmap_update_bits(regmap, SG_USBPCIESEL,
+				   SG_USBPCIESEL_PCIE, SG_USBPCIESEL_PCIE);
+
+	phy_set_drvdata(phy, priv);
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct uniphier_pciephy_soc_data uniphier_ld20_data = {
+	.has_syscon = true,
+};
+
+static const struct uniphier_pciephy_soc_data uniphier_pxs3_data = {
+	.has_syscon = false,
+};
+
+static const struct of_device_id uniphier_pciephy_match[] = {
+	{
+		.compatible = "socionext,uniphier-ld20-pcie-phy",
+		.data = &uniphier_ld20_data,
+	},
+	{
+		.compatible = "socionext,uniphier-pxs3-pcie-phy",
+		.data = &uniphier_pxs3_data,
+	},
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, uniphier_pciephy_match);
+
+static struct platform_driver uniphier_pciephy_driver = {
+	.probe = uniphier_pciephy_probe,
+	.driver = {
+		.name = "uniphier-pcie-phy",
+		.of_match_table = uniphier_pciephy_match,
+	},
+};
+module_platform_driver(uniphier_pciephy_driver);
+
+MODULE_AUTHOR("Kunihiko Hayashi <hayashi.kunihiko@socionext.com>");
+MODULE_DESCRIPTION("UniPhier PHY driver for PCIe controller");
+MODULE_LICENSE("GPL v2");