phy: spacemit: support K1 USB2.0 PHY controller

The SpacemiT K1 SoC includes three USB ports:

- One USB2.0 OTG port
- One USB2.0 host-only port
- One USB3.0 port with an integrated USB2.0 DRD interface

Each of these ports is connected to a USB2.0 PHY responsible for USB2
transmission.

This commit adds support for the SpacemiT K1 USB2.0 PHY, which is
compliant with the USB 2.0 specification and supports both 8-bit 60MHz
and 16-bit 30MHz parallel interfaces.

Signed-off-by: Ze Huang <huang.ze@linux.dev>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: Junzhong Pan <panjunzhong@linux.spacemit.com>
Link: https://patch.msgid.link/20251017-k1-usb2phy-v6-2-7cf9ea2477a1@linux.dev
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/Kconfig

@@ -136,6 +136,7 @@ source "drivers/phy/rockchip/Kconfig"
 source "drivers/phy/samsung/Kconfig"
 source "drivers/phy/socionext/Kconfig"
 source "drivers/phy/sophgo/Kconfig"
+source "drivers/phy/spacemit/Kconfig"
 source "drivers/phy/st/Kconfig"
 source "drivers/phy/starfive/Kconfig"
 source "drivers/phy/sunplus/Kconfig"

drivers/phy/Makefile

@@ -38,6 +38,7 @@ obj-y					+= allwinner/	\
 					   samsung/	\
 					   socionext/	\
 					   sophgo/	\
+					   spacemit/	\
 					   st/		\
 					   starfive/	\
 					   sunplus/	\

drivers/phy/spacemit/Kconfig

@@ -0,0 +1,13 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Phy drivers for SpacemiT platforms
+#
+config PHY_SPACEMIT_K1_USB2
+	tristate "SpacemiT K1 USB 2.0 PHY support"
+	depends on (ARCH_SPACEMIT || COMPILE_TEST) && OF
+	depends on COMMON_CLK
+	depends on USB_COMMON
+	select GENERIC_PHY
+	help
+	  Enable this to support K1 USB 2.0 PHY driver. This driver takes care of
+	  enabling and clock setup and will be used by K1 udc/ehci/otg/xhci driver.

drivers/phy/spacemit/Makefile

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_PHY_SPACEMIT_K1_USB2)		+= phy-k1-usb2.o

drivers/phy/spacemit/phy-k1-usb2.c

@@ -0,0 +1,200 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * SpacemiT K1 USB 2.0 PHY driver
+ *
+ * Copyright (C) 2025 SpacemiT (Hangzhou) Technology Co. Ltd
+ * Copyright (C) 2025 Ze Huang <huang.ze@linux.dev>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/iopoll.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/usb/of.h>
+
+#define PHY_RST_MODE_CTRL		0x04
+#define  PHY_PLL_RDY			BIT(0)
+#define  PHY_CLK_CDR_EN			BIT(1)
+#define  PHY_CLK_PLL_EN			BIT(2)
+#define  PHY_CLK_MAC_EN			BIT(3)
+#define  PHY_MAC_RSTN			BIT(5)
+#define  PHY_CDR_RSTN			BIT(6)
+#define  PHY_PLL_RSTN			BIT(7)
+/*
+ * hs line state sel (Bit 13):
+ * - 1 (Default): Internal HS line state is set to 01 when usb_hs_tx_en is valid.
+ * - 0: Internal HS line state is always driven by usb_hs_lstate.
+ *
+ * fs line state sel (Bit 14):
+ * - 1 (Default): FS line state is determined by the output data
+ * (usb_fs_datain/b).
+ * - 0: FS line state is always determined by the input data (dmo/dpo).
+ */
+#define  PHY_HS_LINE_TX_MODE		BIT(13)
+#define  PHY_FS_LINE_TX_MODE		BIT(14)
+
+#define  PHY_INIT_MODE_BITS		(PHY_FS_LINE_TX_MODE | PHY_HS_LINE_TX_MODE)
+#define  PHY_CLK_ENABLE_BITS		(PHY_CLK_PLL_EN | PHY_CLK_CDR_EN | \
+					 PHY_CLK_MAC_EN)
+#define  PHY_DEASSERT_RST_BITS		(PHY_PLL_RSTN | PHY_CDR_RSTN | \
+					 PHY_MAC_RSTN)
+
+#define PHY_TX_HOST_CTRL		0x10
+#define  PHY_HST_DISC_AUTO_CLR		BIT(2)		/* autoclear hs host disc when re-connect */
+
+#define PHY_HSTXP_HW_CTRL		0x34
+#define  PHY_HSTXP_RSTN			BIT(2)		/* generate reset for clock hstxp */
+#define  PHY_CLK_HSTXP_EN		BIT(3)		/* clock hstxp enable */
+#define  PHY_HSTXP_MODE			BIT(4)		/* 0: force en_txp to be 1; 1: no force */
+
+#define PHY_PLL_DIV_CFG			0x98
+#define  PHY_FDIV_FRACT_8_15		GENMASK(7, 0)
+#define  PHY_FDIV_FRACT_16_19		GENMASK(11, 8)
+#define  PHY_FDIV_FRACT_20_21		BIT(12)		/* fdiv_reg<21>, <20>, bit21 == bit20 */
+/*
+ * freq_sel<1:0>
+ * if ref clk freq=24.0MHz-->freq_sel<2:0> == 3b'001, then internal divider value == 80
+ */
+#define  PHY_FDIV_FRACT_0_1		GENMASK(14, 13)
+/*
+ * pll divider value selection
+ * 1: divider value will choose internal default value ,dependent on freq_sel<1:0>
+ * 0: divider value will be over ride by fdiv_reg<21:0>
+ */
+#define  PHY_DIV_LOCAL_EN		BIT(15)
+
+#define  PHY_SEL_FREQ_24MHZ		0x01
+#define  FDIV_REG_MASK			(PHY_FDIV_FRACT_20_21 | PHY_FDIV_FRACT_16_19 | \
+					 PHY_FDIV_FRACT_8_15)
+#define  FDIV_REG_VAL			0x1ec4		/* 0x100 selects 24MHz, rest are default */
+
+#define K1_USB2PHY_RESET_TIME_MS	50
+
+struct spacemit_usb2phy {
+	struct phy *phy;
+	struct clk *clk;
+	struct regmap *regmap_base;
+};
+
+static const struct regmap_config phy_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = 0x200,
+};
+
+static int spacemit_usb2phy_init(struct phy *phy)
+{
+	struct spacemit_usb2phy *sphy = phy_get_drvdata(phy);
+	struct regmap *map = sphy->regmap_base;
+	u32 val;
+	int ret;
+
+	ret = clk_enable(sphy->clk);
+	if (ret) {
+		dev_err(&phy->dev, "failed to enable clock\n");
+		clk_disable(sphy->clk);
+		return ret;
+	}
+
+	/*
+	 * make sure the usb controller is not under reset process before
+	 * any configuration
+	 */
+	usleep_range(150, 200);
+
+	/* 24M ref clk */
+	val = FIELD_PREP(FDIV_REG_MASK, FDIV_REG_VAL) |
+	      FIELD_PREP(PHY_FDIV_FRACT_0_1, PHY_SEL_FREQ_24MHZ) |
+	      PHY_DIV_LOCAL_EN;
+	regmap_write(map, PHY_PLL_DIV_CFG, val);
+
+	ret = regmap_read_poll_timeout(map, PHY_RST_MODE_CTRL, val,
+				       (val & PHY_PLL_RDY),
+				       500, K1_USB2PHY_RESET_TIME_MS * 1000);
+	if (ret) {
+		dev_err(&phy->dev, "wait PLLREADY timeout\n");
+		clk_disable(sphy->clk);
+		return ret;
+	}
+
+	/* release usb2 phy internal reset and enable clock gating */
+	val = (PHY_INIT_MODE_BITS | PHY_CLK_ENABLE_BITS | PHY_DEASSERT_RST_BITS);
+	regmap_write(map, PHY_RST_MODE_CTRL, val);
+
+	val = (PHY_HSTXP_RSTN | PHY_CLK_HSTXP_EN | PHY_HSTXP_MODE);
+	regmap_write(map, PHY_HSTXP_HW_CTRL, val);
+
+	/* auto clear host disc */
+	regmap_update_bits(map, PHY_TX_HOST_CTRL, PHY_HST_DISC_AUTO_CLR,
+			   PHY_HST_DISC_AUTO_CLR);
+
+	return 0;
+}
+
+static int spacemit_usb2phy_exit(struct phy *phy)
+{
+	struct spacemit_usb2phy *sphy = phy_get_drvdata(phy);
+
+	clk_disable(sphy->clk);
+
+	return 0;
+}
+
+static const struct phy_ops spacemit_usb2phy_ops = {
+	.init = spacemit_usb2phy_init,
+	.exit = spacemit_usb2phy_exit,
+	.owner = THIS_MODULE,
+};
+
+static int spacemit_usb2phy_probe(struct platform_device *pdev)
+{
+	struct phy_provider *phy_provider;
+	struct device *dev = &pdev->dev;
+	struct spacemit_usb2phy *sphy;
+	void __iomem *base;
+
+	sphy = devm_kzalloc(dev, sizeof(*sphy), GFP_KERNEL);
+	if (!sphy)
+		return -ENOMEM;
+
+	sphy->clk = devm_clk_get_prepared(&pdev->dev, NULL);
+	if (IS_ERR(sphy->clk))
+		return dev_err_probe(dev, PTR_ERR(sphy->clk), "Failed to get clock\n");
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	sphy->regmap_base = devm_regmap_init_mmio(dev, base, &phy_regmap_config);
+	if (IS_ERR(sphy->regmap_base))
+		return dev_err_probe(dev, PTR_ERR(sphy->regmap_base), "Failed to init regmap\n");
+
+	sphy->phy = devm_phy_create(dev, NULL, &spacemit_usb2phy_ops);
+	if (IS_ERR(sphy->phy))
+		return dev_err_probe(dev, PTR_ERR(sphy->phy), "Failed to create phy\n");
+
+	phy_set_drvdata(sphy->phy, sphy);
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id spacemit_usb2phy_dt_match[] = {
+	{ .compatible = "spacemit,k1-usb2-phy", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, spacemit_usb2phy_dt_match);
+
+static struct platform_driver spacemit_usb2_phy_driver = {
+	.probe	= spacemit_usb2phy_probe,
+	.driver = {
+		.name   = "spacemit-usb2-phy",
+		.of_match_table = spacemit_usb2phy_dt_match,
+	},
+};
+module_platform_driver(spacemit_usb2_phy_driver);
+
+MODULE_DESCRIPTION("Spacemit USB 2.0 PHY driver");
+MODULE_LICENSE("GPL");