phy: sun50i-usb3: Add a driver for the H6 USB3 PHY

This driver is needed for XHCI to work on the Allwinner H6 SoC. The
driver is copied from Linux v5.10.

Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

drivers/phy/allwinner/Kconfig

@@ -11,3 +11,11 @@ config PHY_SUN4I_USB
 
 	  This driver controls the entire USB PHY block, both the USB OTG
 	  parts, as well as the 2 regular USB 2 host PHYs.
+
+config PHY_SUN50I_USB3
+	bool "Allwinner sun50i USB3 PHY driver"
+	depends on ARCH_SUNXI
+	select PHY
+	help
+	  Enable this to support the USB3 transceiver that is part of
+	  Allwinner sun50i SoCs.

drivers/phy/allwinner/Makefile

@@ -4,3 +4,4 @@
 #
 
 obj-$(CONFIG_PHY_SUN4I_USB)		+= phy-sun4i-usb.o
+obj-$(CONFIG_PHY_SUN50I_USB3)		+= phy-sun50i-usb3.o

drivers/phy/allwinner/phy-sun50i-usb3.c

@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Allwinner sun50i(H6) USB 3.0 phy driver
+ *
+ * Copyright (C) 2020 Samuel Holland <samuel@sholland.org>
+ *
+ * Based on the Linux driver, which is:
+ *
+ * Copyright (C) 2017 Icenowy Zheng <icenowy@aosc.io>
+ *
+ * Based on phy-sun9i-usb.c, which is:
+ *
+ * Copyright (C) 2014-2015 Chen-Yu Tsai <wens@csie.org>
+ *
+ * Based on code from Allwinner BSP, which is:
+ *
+ * Copyright (c) 2010-2015 Allwinner Technology Co., Ltd.
+ */
+
+#include <asm/io.h>
+#include <clk.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <generic-phy.h>
+#include <linux/bitops.h>
+#include <reset.h>
+
+/* Interface Status and Control Registers */
+#define SUNXI_ISCR			0x00
+#define SUNXI_PIPE_CLOCK_CONTROL	0x14
+#define SUNXI_PHY_TUNE_LOW		0x18
+#define SUNXI_PHY_TUNE_HIGH		0x1c
+#define SUNXI_PHY_EXTERNAL_CONTROL	0x20
+
+/* USB2.0 Interface Status and Control Register */
+#define SUNXI_ISCR_FORCE_VBUS		(3 << 12)
+
+/* PIPE Clock Control Register */
+#define SUNXI_PCC_PIPE_CLK_OPEN		(1 << 6)
+
+/* PHY External Control Register */
+#define SUNXI_PEC_EXTERN_VBUS		(3 << 1)
+#define SUNXI_PEC_SSC_EN		(1 << 24)
+#define SUNXI_PEC_REF_SSP_EN		(1 << 26)
+
+/* PHY Tune High Register */
+#define SUNXI_TX_DEEMPH_3P5DB(n)	((n) << 19)
+#define SUNXI_TX_DEEMPH_3P5DB_MASK	GENMASK(24, 19)
+#define SUNXI_TX_DEEMPH_6DB(n)		((n) << 13)
+#define SUNXI_TX_DEEMPH_6GB_MASK	GENMASK(18, 13)
+#define SUNXI_TX_SWING_FULL(n)		((n) << 6)
+#define SUNXI_TX_SWING_FULL_MASK	GENMASK(12, 6)
+#define SUNXI_LOS_BIAS(n)		((n) << 3)
+#define SUNXI_LOS_BIAS_MASK		GENMASK(5, 3)
+#define SUNXI_TXVBOOSTLVL(n)		((n) << 0)
+#define SUNXI_TXVBOOSTLVL_MASK		GENMASK(2, 0)
+
+struct sun50i_usb3_phy_priv {
+	void __iomem *regs;
+	struct reset_ctl reset;
+	struct clk clk;
+};
+
+static void sun50i_usb3_phy_open(struct sun50i_usb3_phy_priv *phy)
+{
+	u32 val;
+
+	val = readl(phy->regs + SUNXI_PHY_EXTERNAL_CONTROL);
+	val |= SUNXI_PEC_EXTERN_VBUS;
+	val |= SUNXI_PEC_SSC_EN | SUNXI_PEC_REF_SSP_EN;
+	writel(val, phy->regs + SUNXI_PHY_EXTERNAL_CONTROL);
+
+	val = readl(phy->regs + SUNXI_PIPE_CLOCK_CONTROL);
+	val |= SUNXI_PCC_PIPE_CLK_OPEN;
+	writel(val, phy->regs + SUNXI_PIPE_CLOCK_CONTROL);
+
+	val = readl(phy->regs + SUNXI_ISCR);
+	val |= SUNXI_ISCR_FORCE_VBUS;
+	writel(val, phy->regs + SUNXI_ISCR);
+
+	/*
+	 * All the magic numbers written to the PHY_TUNE_{LOW_HIGH}
+	 * registers are directly taken from the BSP USB3 driver from
+	 * Allwiner.
+	 */
+	writel(0x0047fc87, phy->regs + SUNXI_PHY_TUNE_LOW);
+
+	val = readl(phy->regs + SUNXI_PHY_TUNE_HIGH);
+	val &= ~(SUNXI_TXVBOOSTLVL_MASK | SUNXI_LOS_BIAS_MASK |
+		 SUNXI_TX_SWING_FULL_MASK | SUNXI_TX_DEEMPH_6GB_MASK |
+		 SUNXI_TX_DEEMPH_3P5DB_MASK);
+	val |= SUNXI_TXVBOOSTLVL(0x7);
+	val |= SUNXI_LOS_BIAS(0x7);
+	val |= SUNXI_TX_SWING_FULL(0x55);
+	val |= SUNXI_TX_DEEMPH_6DB(0x20);
+	val |= SUNXI_TX_DEEMPH_3P5DB(0x15);
+	writel(val, phy->regs + SUNXI_PHY_TUNE_HIGH);
+}
+
+static int sun50i_usb3_phy_init(struct phy *phy)
+{
+	struct sun50i_usb3_phy_priv *priv = dev_get_priv(phy->dev);
+	int ret;
+
+	ret = clk_prepare_enable(&priv->clk);
+	if (ret)
+		return ret;
+
+	ret = reset_deassert(&priv->reset);
+	if (ret) {
+		clk_disable_unprepare(&priv->clk);
+		return ret;
+	}
+
+	sun50i_usb3_phy_open(priv);
+
+	return 0;
+}
+
+static int sun50i_usb3_phy_exit(struct phy *phy)
+{
+	struct sun50i_usb3_phy_priv *priv = dev_get_priv(phy->dev);
+
+	reset_assert(&priv->reset);
+	clk_disable_unprepare(&priv->clk);
+
+	return 0;
+}
+
+static const struct phy_ops sun50i_usb3_phy_ops = {
+	.init		= sun50i_usb3_phy_init,
+	.exit		= sun50i_usb3_phy_exit,
+};
+
+static int sun50i_usb3_phy_probe(struct udevice *dev)
+{
+	struct sun50i_usb3_phy_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = clk_get_by_index(dev, 0, &priv->clk);
+	if (ret) {
+		dev_err(dev, "failed to get phy clock\n");
+		return ret;
+	}
+
+	ret = reset_get_by_index(dev, 0, &priv->reset);
+	if (ret) {
+		dev_err(dev, "failed to get reset control\n");
+		return ret;
+	}
+
+	priv->regs = (void __iomem *)dev_read_addr(dev);
+	if (IS_ERR(priv->regs))
+		return PTR_ERR(priv->regs);
+
+	return 0;
+}
+
+static const struct udevice_id sun50i_usb3_phy_ids[] = {
+	{ .compatible = "allwinner,sun50i-h6-usb3-phy" },
+	{ },
+};
+
+U_BOOT_DRIVER(sun50i_usb3_phy) = {
+	.name		= "sun50i-usb3-phy",
+	.id		= UCLASS_PHY,
+	.of_match	= sun50i_usb3_phy_ids,
+	.ops		= &sun50i_usb3_phy_ops,
+	.probe		= sun50i_usb3_phy_probe,
+	.priv_auto	= sizeof(struct sun50i_usb3_phy_priv),
+};