phy: Add support for drivers to enable USB on QCS404 SoC

QCS404 SoC supports two types of PHY, one supports high speed mode or
USB2 PHY and the other supports super speed mode or USB3 PHY. So add
corresponding PHY drivers.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
diff --git a/drivers/phy/qcom/phy-qcom-usb-ss.c b/drivers/phy/qcom/phy-qcom-usb-ss.c
new file mode 100644
index 0000000..4e81687
--- /dev/null
+++ b/drivers/phy/qcom/phy-qcom-usb-ss.c
@@ -0,0 +1,154 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2022 Sumit Garg <sumit.garg@linaro.org>
+ *
+ * Based on Linux driver
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <generic-phy.h>
+#include <linux/bitops.h>
+#include <asm/io.h>
+#include <reset.h>
+#include <clk.h>
+#include <linux/delay.h>
+
+#define PHY_CTRL0			0x6C
+#define PHY_CTRL1			0x70
+#define PHY_CTRL2			0x74
+#define PHY_CTRL4			0x7C
+
+/* PHY_CTRL bits */
+#define REF_PHY_EN			BIT(0)
+#define LANE0_PWR_ON			BIT(2)
+#define SWI_PCS_CLK_SEL			BIT(4)
+#define TST_PWR_DOWN			BIT(4)
+#define PHY_RESET			BIT(7)
+
+struct ssphy_priv {
+	void __iomem *base;
+	struct clk_bulk clks;
+	struct reset_ctl com_rst;
+	struct reset_ctl phy_rst;
+};
+
+static inline void ssphy_updatel(void __iomem *addr, u32 mask, u32 val)
+{
+	writel((readl(addr) & ~mask) | val, addr);
+}
+
+static int ssphy_do_reset(struct ssphy_priv *priv)
+{
+	int ret;
+
+	ret = reset_assert(&priv->com_rst);
+	if (ret)
+		return ret;
+
+	ret = reset_assert(&priv->phy_rst);
+	if (ret)
+		return ret;
+
+	udelay(10);
+
+	ret = reset_deassert(&priv->com_rst);
+	if (ret)
+		return ret;
+
+	ret = reset_deassert(&priv->phy_rst);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int ssphy_power_on(struct phy *phy)
+{
+	struct ssphy_priv *priv = dev_get_priv(phy->dev);
+	int ret;
+
+	ret = ssphy_do_reset(priv);
+	if (ret)
+		return ret;
+
+	writeb(SWI_PCS_CLK_SEL, priv->base + PHY_CTRL0);
+	ssphy_updatel(priv->base + PHY_CTRL4, LANE0_PWR_ON, LANE0_PWR_ON);
+	ssphy_updatel(priv->base + PHY_CTRL2, REF_PHY_EN, REF_PHY_EN);
+	ssphy_updatel(priv->base + PHY_CTRL4, TST_PWR_DOWN, 0);
+
+	return 0;
+}
+
+static int ssphy_power_off(struct phy *phy)
+{
+	struct ssphy_priv *priv = dev_get_priv(phy->dev);
+
+	ssphy_updatel(priv->base + PHY_CTRL4, LANE0_PWR_ON, 0);
+	ssphy_updatel(priv->base + PHY_CTRL2, REF_PHY_EN, 0);
+	ssphy_updatel(priv->base + PHY_CTRL4, TST_PWR_DOWN, TST_PWR_DOWN);
+
+	return 0;
+}
+
+static int ssphy_clk_init(struct udevice *dev, struct ssphy_priv *priv)
+{
+	int ret;
+
+	ret = clk_get_bulk(dev, &priv->clks);
+	if (ret == -ENOSYS || ret == -ENOENT)
+		return 0;
+	if (ret)
+		return ret;
+
+	ret = clk_enable_bulk(&priv->clks);
+	if (ret) {
+		clk_release_bulk(&priv->clks);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ssphy_probe(struct udevice *dev)
+{
+	struct ssphy_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	priv->base = (void *)dev_read_addr(dev);
+	if ((ulong)priv->base == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	ret = ssphy_clk_init(dev, priv);
+	if (ret)
+		return ret;
+
+	ret = reset_get_by_name(dev, "com", &priv->com_rst);
+	if (ret)
+		return ret;
+
+	ret = reset_get_by_name(dev, "phy", &priv->phy_rst);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static struct phy_ops ssphy_ops = {
+	.power_on = ssphy_power_on,
+	.power_off = ssphy_power_off,
+};
+
+static const struct udevice_id ssphy_ids[] = {
+	{ .compatible = "qcom,usb-ss-28nm-phy" },
+	{ }
+};
+
+U_BOOT_DRIVER(qcom_usb_ss) = {
+	.name		= "qcom-usb-ss",
+	.id		= UCLASS_PHY,
+	.of_match	= ssphy_ids,
+	.ops		= &ssphy_ops,
+	.probe		= ssphy_probe,
+	.priv_auto	= sizeof(struct ssphy_priv),
+};