phy: Add an USB PHY driver for the Lantiq SoCs using the RCU module

This driver starts the DWC2 core(s) built into the XWAY SoCs and provides
the PHY interfaces for each core. The phy instances can be passed to the
dwc2 driver, which already supports the generic phy interface.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Rob Herring <robh@kernel.org>
Cc: martin.blumenstingl@googlemail.com
Cc: john@phrozen.org
Cc: andy.shevchenko@gmail.com
Cc: p.zabel@pengutronix.de
Cc: mark.rutland@arm.com
Cc: linux-mips@linux-mips.org
Cc: linux-mtd@lists.infradead.org
Cc: linux-watchdog@vger.kernel.org
Cc: devicetree@vger.kernel.org
Cc: linux-spi@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17127/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

3 files changed, 264 insertions, 0 deletions

diff --git a/drivers/phy/lantiq/Kconfig b/drivers/phy/lantiq/Kconfig
new file mode 100644
index 000000000000..326d88a6417d
--- /dev/null
+++ b/drivers/phy/lantiq/Kconfig
@@ -0,0 +1,9 @@
+#
+# Phy drivers for Lantiq / Intel platforms
+#
+config PHY_LANTIQ_RCU_USB2
+	tristate "Lantiq XWAY SoC RCU based USB PHY"
+	depends on OF && (SOC_TYPE_XWAY || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Support for the USB PHY(s) on the Lantiq / Intel XWAY family SoCs.
diff --git a/drivers/phy/lantiq/Makefile b/drivers/phy/lantiq/Makefile
new file mode 100644
index 000000000000..f73eb56a5416
--- /dev/null
+++ b/drivers/phy/lantiq/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_PHY_LANTIQ_RCU_USB2)	+= phy-lantiq-rcu-usb2.o
diff --git a/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c b/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c
new file mode 100644
index 000000000000..986224fca9e9
--- /dev/null
+++ b/drivers/phy/lantiq/phy-lantiq-rcu-usb2.c
@@ -0,0 +1,254 @@
+/*
+ * Lantiq XWAY SoC RCU module based USB 1.1/2.0 PHY driver
+ *
+ * Copyright (C) 2016 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+ * Copyright (C) 2017 Hauke Mehrtens <hauke@hauke-m.de>
+ *
+ * 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/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+/* Transmitter HS Pre-Emphasis Enable */
+#define RCU_CFG1_TX_PEE		BIT(0)
+/* Disconnect Threshold */
+#define RCU_CFG1_DIS_THR_MASK	0x00038000
+#define RCU_CFG1_DIS_THR_SHIFT	15
+
+struct ltq_rcu_usb2_bits {
+	u8 hostmode;
+	u8 slave_endianness;
+	u8 host_endianness;
+	bool have_ana_cfg;
+};
+
+struct ltq_rcu_usb2_priv {
+	struct regmap			*regmap;
+	unsigned int			phy_reg_offset;
+	unsigned int			ana_cfg1_reg_offset;
+	const struct ltq_rcu_usb2_bits	*reg_bits;
+	struct device			*dev;
+	struct phy			*phy;
+	struct clk			*phy_gate_clk;
+	struct reset_control		*ctrl_reset;
+	struct reset_control		*phy_reset;
+};
+
+static const struct ltq_rcu_usb2_bits xway_rcu_usb2_reg_bits = {
+	.hostmode = 11,
+	.slave_endianness = 9,
+	.host_endianness = 10,
+	.have_ana_cfg = false,
+};
+
+static const struct ltq_rcu_usb2_bits xrx100_rcu_usb2_reg_bits = {
+	.hostmode = 11,
+	.slave_endianness = 17,
+	.host_endianness = 10,
+	.have_ana_cfg = false,
+};
+
+static const struct ltq_rcu_usb2_bits xrx200_rcu_usb2_reg_bits = {
+	.hostmode = 11,
+	.slave_endianness = 9,
+	.host_endianness = 10,
+	.have_ana_cfg = true,
+};
+
+static const struct of_device_id ltq_rcu_usb2_phy_of_match[] = {
+	{
+		.compatible = "lantiq,ase-usb2-phy",
+		.data = &xway_rcu_usb2_reg_bits,
+	},
+	{
+		.compatible = "lantiq,danube-usb2-phy",
+		.data = &xway_rcu_usb2_reg_bits,
+	},
+	{
+		.compatible = "lantiq,xrx100-usb2-phy",
+		.data = &xrx100_rcu_usb2_reg_bits,
+	},
+	{
+		.compatible = "lantiq,xrx200-usb2-phy",
+		.data = &xrx200_rcu_usb2_reg_bits,
+	},
+	{
+		.compatible = "lantiq,xrx300-usb2-phy",
+		.data = &xrx200_rcu_usb2_reg_bits,
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ltq_rcu_usb2_phy_of_match);
+
+static int ltq_rcu_usb2_phy_init(struct phy *phy)
+{
+	struct ltq_rcu_usb2_priv *priv = phy_get_drvdata(phy);
+
+	if (priv->reg_bits->have_ana_cfg) {
+		regmap_update_bits(priv->regmap, priv->ana_cfg1_reg_offset,
+			RCU_CFG1_TX_PEE, RCU_CFG1_TX_PEE);
+		regmap_update_bits(priv->regmap, priv->ana_cfg1_reg_offset,
+			RCU_CFG1_DIS_THR_MASK, 7 << RCU_CFG1_DIS_THR_SHIFT);
+	}
+
+	/* Configure core to host mode */
+	regmap_update_bits(priv->regmap, priv->phy_reg_offset,
+			   BIT(priv->reg_bits->hostmode), 0);
+
+	/* Select DMA endianness (Host-endian: big-endian) */
+	regmap_update_bits(priv->regmap, priv->phy_reg_offset,
+		BIT(priv->reg_bits->slave_endianness), 0);
+	regmap_update_bits(priv->regmap, priv->phy_reg_offset,
+		BIT(priv->reg_bits->host_endianness),
+		BIT(priv->reg_bits->host_endianness));
+
+	return 0;
+}
+
+static int ltq_rcu_usb2_phy_power_on(struct phy *phy)
+{
+	struct ltq_rcu_usb2_priv *priv = phy_get_drvdata(phy);
+	struct device *dev = priv->dev;
+	int ret;
+
+	reset_control_deassert(priv->phy_reset);
+
+	ret = clk_prepare_enable(priv->phy_gate_clk);
+	if (ret)
+		dev_err(dev, "failed to enable PHY gate\n");
+
+	return ret;
+}
+
+static int ltq_rcu_usb2_phy_power_off(struct phy *phy)
+{
+	struct ltq_rcu_usb2_priv *priv = phy_get_drvdata(phy);
+
+	reset_control_assert(priv->phy_reset);
+
+	clk_disable_unprepare(priv->phy_gate_clk);
+
+	return 0;
+}
+
+static struct phy_ops ltq_rcu_usb2_phy_ops = {
+	.init		= ltq_rcu_usb2_phy_init,
+	.power_on	= ltq_rcu_usb2_phy_power_on,
+	.power_off	= ltq_rcu_usb2_phy_power_off,
+	.owner		= THIS_MODULE,
+};
+
+static int ltq_rcu_usb2_of_parse(struct ltq_rcu_usb2_priv *priv,
+				 struct platform_device *pdev)
+{
+	struct device *dev = priv->dev;
+	const __be32 *offset;
+	int ret;
+
+	priv->reg_bits = of_device_get_match_data(dev);
+
+	priv->regmap = syscon_node_to_regmap(dev->of_node->parent);
+	if (IS_ERR(priv->regmap)) {
+		dev_err(dev, "Failed to lookup RCU regmap\n");
+		return PTR_ERR(priv->regmap);
+	}
+
+	offset = of_get_address(dev->of_node, 0, NULL, NULL);
+	if (!offset) {
+		dev_err(dev, "Failed to get RCU PHY reg offset\n");
+		return -ENOENT;
+	}
+	priv->phy_reg_offset = __be32_to_cpu(*offset);
+
+	if (priv->reg_bits->have_ana_cfg) {
+		offset = of_get_address(dev->of_node, 1, NULL, NULL);
+		if (!offset) {
+			dev_err(dev, "Failed to get RCU ANA CFG1 reg offset\n");
+			return -ENOENT;
+		}
+		priv->ana_cfg1_reg_offset = __be32_to_cpu(*offset);
+	}
+
+	priv->phy_gate_clk = devm_clk_get(dev, "phy");
+	if (IS_ERR(priv->phy_gate_clk)) {
+		dev_err(dev, "Unable to get USB phy gate clk\n");
+		return PTR_ERR(priv->phy_gate_clk);
+	}
+
+	priv->ctrl_reset = devm_reset_control_get_shared(dev, "ctrl");
+	if (IS_ERR(priv->ctrl_reset)) {
+		if (PTR_ERR(priv->ctrl_reset) != -EPROBE_DEFER)
+			dev_err(dev, "failed to get 'ctrl' reset\n");
+		return PTR_ERR(priv->ctrl_reset);
+	}
+
+	priv->phy_reset = devm_reset_control_get_optional(dev, "phy");
+	if (IS_ERR(priv->phy_reset))
+		return PTR_ERR(priv->phy_reset);
+
+	return 0;
+}
+
+static int ltq_rcu_usb2_phy_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ltq_rcu_usb2_priv *priv;
+	struct phy_provider *provider;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->dev = dev;
+
+	ret = ltq_rcu_usb2_of_parse(priv, pdev);
+	if (ret)
+		return ret;
+
+	/* Reset USB core through reset controller */
+	reset_control_deassert(priv->ctrl_reset);
+
+	reset_control_assert(priv->phy_reset);
+
+	priv->phy = devm_phy_create(dev, dev->of_node, &ltq_rcu_usb2_phy_ops);
+	if (IS_ERR(priv->phy)) {
+		dev_err(dev, "failed to create PHY\n");
+		return PTR_ERR(priv->phy);
+	}
+
+	phy_set_drvdata(priv->phy, priv);
+
+	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(provider))
+		return PTR_ERR(provider);
+
+	dev_set_drvdata(priv->dev, priv);
+	return 0;
+}
+
+static struct platform_driver ltq_rcu_usb2_phy_driver = {
+	.probe	= ltq_rcu_usb2_phy_probe,
+	.driver = {
+		.name	= "lantiq-rcu-usb2-phy",
+		.of_match_table	= ltq_rcu_usb2_phy_of_match,
+	}
+};
+module_platform_driver(ltq_rcu_usb2_phy_driver);
+
+MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
+MODULE_DESCRIPTION("Lantiq XWAY USB2 PHY driver");
+MODULE_LICENSE("GPL v2");