[PATCH v3 2/2] phy: nuvoton: add new driver for the Nuvoton MA35 SoC USB 2.0 PHY

[Hui-Ping Chen <hpchen0nvt@gmail.com>]

Nuvoton MA35 SoCs support DWC2 USB controller.
Add the driver to drive the USB 2.0 PHY transceivers.

Signed-off-by: Hui-Ping Chen <hpchen0nvt@gmail.com>
---
 drivers/phy/Kconfig                   |   1 +
 drivers/phy/Makefile                  |   1 +
 drivers/phy/nuvoton/Kconfig           |  13 +++
 drivers/phy/nuvoton/Makefile          |   3 +
 drivers/phy/nuvoton/phy-ma35d1-usb2.c | 146 ++++++++++++++++++++++++++
 5 files changed, 164 insertions(+)
 create mode 100644 drivers/phy/nuvoton/Kconfig
 create mode 100644 drivers/phy/nuvoton/Makefile
 create mode 100644 drivers/phy/nuvoton/phy-ma35d1-usb2.c

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index dfab1c66b3e5..f73abff416be 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -95,6 +95,7 @@ source "drivers/phy/mediatek/Kconfig"
 source "drivers/phy/microchip/Kconfig"
 source "drivers/phy/motorola/Kconfig"
 source "drivers/phy/mscc/Kconfig"
+source "drivers/phy/nuvoton/Kconfig"
 source "drivers/phy/qualcomm/Kconfig"
 source "drivers/phy/ralink/Kconfig"
 source "drivers/phy/realtek/Kconfig"
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index 5fcbce5f9ab1..ebc399560da4 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -25,6 +25,7 @@ obj-y					+= allwinner/	\
 					   microchip/	\
 					   motorola/	\
 					   mscc/	\
+					   nuvoton/	\
 					   qualcomm/	\
 					   ralink/	\
 					   realtek/	\
diff --git a/drivers/phy/nuvoton/Kconfig b/drivers/phy/nuvoton/Kconfig
new file mode 100644
index 000000000000..270ee2943287
--- /dev/null
+++ b/drivers/phy/nuvoton/Kconfig
@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# PHY drivers for Nuvoton MA35 platforms
+#
+config PHY_MA35_USB
+	tristate "Nuvoton MA35 USB2.0 PHY driver"
+	depends on ARCH_MA35 || COMPILE_TEST
+	depends on OF
+	select GENERIC_PHY
+	help
+	  Enable this to support the USB2.0 PHY on the Nuvoton MA35
+	  series SoCs.
+
diff --git a/drivers/phy/nuvoton/Makefile b/drivers/phy/nuvoton/Makefile
new file mode 100644
index 000000000000..2937e3921898
--- /dev/null
+++ b/drivers/phy/nuvoton/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_PHY_MA35_USB)		+= phy-ma35d1-usb2.o
diff --git a/drivers/phy/nuvoton/phy-ma35d1-usb2.c b/drivers/phy/nuvoton/phy-ma35d1-usb2.c
new file mode 100644
index 000000000000..8922e5da8e3b
--- /dev/null
+++ b/drivers/phy/nuvoton/phy-ma35d1-usb2.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2024 Nuvoton Technology Corp.
+ */
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* USB PHY Miscellaneous Control Register */
+#define MA35_SYS_REG_USBPMISCR	0x60
+#define PHY0POR			BIT(0)  /* PHY Power-On Reset Control Bit */
+#define PHY0SUSPEND			BIT(1)  /* PHY Suspend; 0: suspend, 1: operaion */
+#define PHY0COMN			BIT(2)  /* PHY Common Block Power-Down Control */
+#define PHY0DEVCKSTB			BIT(10) /* PHY 60 MHz UTMI clock stable bit */
+
+struct ma35_usb_phy {
+	struct clk *clk;
+	struct device *dev;
+	struct regmap *sysreg;
+};
+
+static int ma35_usb_phy_power_on(struct phy *phy)
+{
+	struct ma35_usb_phy *p_phy = phy_get_drvdata(phy);
+	unsigned int val;
+	int ret;
+
+	ret = clk_prepare_enable(p_phy->clk);
+	if (ret < 0) {
+		dev_err(p_phy->dev, "Failed to enable PHY clock: %d\n", ret);
+		return ret;
+	}
+
+	regmap_read(p_phy->sysreg, MA35_SYS_REG_USBPMISCR, &val);
+	if (val & PHY0SUSPEND) {
+		/*
+		 * USB PHY0 is in operation mode already
+		 * make sure USB PHY 60 MHz UTMI Interface Clock ready
+		 */
+		ret = readl_poll_timeout((void __iomem *)p_phy->sysreg + MA35_SYS_REG_USBPMISCR,
+					 val, val & PHY0DEVCKSTB, 1, 100);
+		if (ret == -ETIMEDOUT) {
+			dev_err(p_phy->dev, "1.Check PHY clock, Timeout: %d\n", val);
+			return ret;
+		}
+		return 0;
+	}
+
+	/*
+	 * reset USB PHY0.
+	 * wait until USB PHY0 60 MHz UTMI Interface Clock ready
+	 */
+	regmap_update_bits(p_phy->sysreg, MA35_SYS_REG_USBPMISCR, 0x7, (PHY0POR | PHY0SUSPEND));
+	udelay(10);
+
+	/* make USB PHY0 enter operation mode */
+	regmap_update_bits(p_phy->sysreg, MA35_SYS_REG_USBPMISCR, 0x7, PHY0SUSPEND);
+
+	/* make sure USB PHY 60 MHz UTMI Interface Clock ready */
+	ret = readl_poll_timeout((void __iomem *)p_phy->sysreg + MA35_SYS_REG_USBPMISCR,
+				 val, val & PHY0DEVCKSTB, 1, 100);
+	if (ret == -ETIMEDOUT) {
+		dev_err(p_phy->dev, "2.Check PHY clock, Timeout: %d\n", ret);
+		return ret;
+	}
+
+	clk_disable_unprepare(p_phy->clk);
+	return 0;
+}
+
+static int ma35_usb_phy_power_off(struct phy *phy)
+{
+	struct ma35_usb_phy *p_phy = phy_get_drvdata(phy);
+
+	clk_disable_unprepare(p_phy->clk);
+	return 0;
+}
+
+static const struct phy_ops ma35_usb_phy_ops = {
+	.power_on = ma35_usb_phy_power_on,
+	.power_off = ma35_usb_phy_power_off,
+	.owner = THIS_MODULE,
+};
+
+static int ma35_usb_phy_probe(struct platform_device *pdev)
+{
+	struct phy_provider *provider;
+	struct ma35_usb_phy *p_phy;
+	struct phy *phy;
+
+	p_phy = devm_kzalloc(&pdev->dev, sizeof(*p_phy), GFP_KERNEL);
+	if (!p_phy)
+		return -ENOMEM;
+
+	p_phy->dev = &pdev->dev;
+	platform_set_drvdata(pdev, p_phy);
+
+	p_phy->sysreg = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "nuvoton,sys");
+	if (IS_ERR(p_phy->sysreg))
+		return dev_err_probe(&pdev->dev, PTR_ERR(p_phy->sysreg),
+				     "Failed to get SYS registers\n");
+
+	p_phy->clk = of_clk_get(pdev->dev.of_node, 0);
+	if (IS_ERR(p_phy->clk))
+		return dev_err_probe(&pdev->dev, PTR_ERR(p_phy->clk),
+				     "failed to find usb_phy clock\n");
+
+	phy = devm_phy_create(&pdev->dev, NULL, &ma35_usb_phy_ops);
+	if (IS_ERR(phy))
+		return dev_err_probe(&pdev->dev, PTR_ERR(phy), "Failed to create PHY\n");
+
+	phy_set_drvdata(phy, p_phy);
+
+	provider = devm_of_phy_provider_register(&pdev->dev, of_phy_simple_xlate);
+	if (IS_ERR(provider))
+		return dev_err_probe(&pdev->dev, PTR_ERR(provider),
+				     "Failed to register PHY provider\n");
+	return 0;
+}
+
+static const struct of_device_id ma35_usb_phy_of_match[] = {
+	{ .compatible = "nuvoton,ma35d1-usb2-phy", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, ma35_usb_phy_of_match);
+
+static struct platform_driver ma35_usb_phy_driver = {
+	.probe		= ma35_usb_phy_probe,
+	.driver	= {
+		.name	= "ma35d1-usb2-phy",
+		.of_match_table = ma35_usb_phy_of_match,
+	},
+};
+module_platform_driver(ma35_usb_phy_driver);
+
+MODULE_DESCRIPTION("Nuvoton ma35d1 USB2.0 PHY driver");
+MODULE_AUTHOR("hpchen0nvt@gmail.com");
+MODULE_LICENSE("GPL");
-- 
2.25.1