phy: meson: add Amlogic G12A USB2 and USB3+PCIE PHY drivers

This adds support for the USB PHYs found in the Amlogic G12A SoC Family.

The USB2 PHY supports Host and/or Peripheral mode, depending on it's position.
The first PHY is only used as Host, but the second supports Dual modes
defined by the USB Control Glue HW in front of the USB Controllers.

The second driver supports USB3 Host mode or PCIE 2.0 mode, depending on
the layout of the board.
Selection is done by the #phy-cells, making the mode static and exclusive.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/drivers/phy/meson-g12a-usb3-pcie.c b/drivers/phy/meson-g12a-usb3-pcie.c
new file mode 100644
index 0000000..920675d
--- /dev/null
+++ b/drivers/phy/meson-g12a-usb3-pcie.c
@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Meson G12A USB3+PCIE Combo PHY driver
+ *
+ * Copyright (C) 2018 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
+ * Copyright (C) 2019 BayLibre, SAS
+ * Author: Neil Armstrong <narmstron@baylibre.com>
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <regmap.h>
+#include <errno.h>
+#include <asm/io.h>
+#include <reset.h>
+#include <bitfield.h>
+#include <generic-phy.h>
+
+#include <linux/bitops.h>
+#include <linux/compat.h>
+#include <linux/bitfield.h>
+
+#define PHY_R0							0x00
+	#define PHY_R0_PCIE_POWER_STATE				GENMASK(4, 0)
+	#define PHY_R0_PCIE_USB3_SWITCH				GENMASK(6, 5)
+
+#define PHY_R1							0x04
+	#define PHY_R1_PHY_TX1_TERM_OFFSET			GENMASK(4, 0)
+	#define PHY_R1_PHY_TX0_TERM_OFFSET			GENMASK(9, 5)
+	#define PHY_R1_PHY_RX1_EQ				GENMASK(12, 10)
+	#define PHY_R1_PHY_RX0_EQ				GENMASK(15, 13)
+	#define PHY_R1_PHY_LOS_LEVEL				GENMASK(20, 16)
+	#define PHY_R1_PHY_LOS_BIAS				GENMASK(23, 21)
+	#define PHY_R1_PHY_REF_CLKDIV2				BIT(24)
+	#define PHY_R1_PHY_MPLL_MULTIPLIER			GENMASK(31, 25)
+
+#define PHY_R2							0x08
+	#define PHY_R2_PCS_TX_DEEMPH_GEN2_6DB			GENMASK(5, 0)
+	#define PHY_R2_PCS_TX_DEEMPH_GEN2_3P5DB			GENMASK(11, 6)
+	#define PHY_R2_PCS_TX_DEEMPH_GEN1			GENMASK(17, 12)
+	#define PHY_R2_PHY_TX_VBOOST_LVL			GENMASK(20, 18)
+
+#define PHY_R4							0x10
+	#define PHY_R4_PHY_CR_WRITE				BIT(0)
+	#define PHY_R4_PHY_CR_READ				BIT(1)
+	#define PHY_R4_PHY_CR_DATA_IN				GENMASK(17, 2)
+	#define PHY_R4_PHY_CR_CAP_DATA				BIT(18)
+	#define PHY_R4_PHY_CR_CAP_ADDR				BIT(19)
+
+#define PHY_R5							0x14
+	#define PHY_R5_PHY_CR_DATA_OUT				GENMASK(15, 0)
+	#define PHY_R5_PHY_CR_ACK				BIT(16)
+	#define PHY_R5_PHY_BS_OUT				BIT(17)
+
+struct phy_g12a_usb3_pcie_priv {
+	struct regmap		*regmap;
+#if CONFIG_IS_ENABLED(CLK)
+	struct clk		clk;
+#endif
+	struct reset_ctl_bulk	resets;
+};
+
+static int phy_g12a_usb3_pcie_cr_bus_addr(struct phy_g12a_usb3_pcie_priv *priv,
+					  unsigned int addr)
+{
+	unsigned int val, reg;
+	int ret;
+
+	reg = FIELD_PREP(PHY_R4_PHY_CR_DATA_IN, addr);
+
+	regmap_write(priv->regmap, PHY_R4, reg);
+	regmap_write(priv->regmap, PHY_R4, reg);
+
+	regmap_write(priv->regmap, PHY_R4, reg | PHY_R4_PHY_CR_CAP_ADDR);
+
+	ret = regmap_read_poll_timeout(priv->regmap, PHY_R5, val,
+				       (val & PHY_R5_PHY_CR_ACK),
+				       5, 1000);
+	if (ret)
+		return ret;
+
+	regmap_write(priv->regmap, PHY_R4, reg);
+
+	ret = regmap_read_poll_timeout(priv->regmap, PHY_R5, val,
+				       !(val & PHY_R5_PHY_CR_ACK),
+				       5, 1000);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int
+phy_g12a_usb3_pcie_cr_bus_read(struct phy_g12a_usb3_pcie_priv *priv,
+			       unsigned int addr, unsigned int *data)
+{
+	unsigned int val;
+	int ret;
+
+	ret = phy_g12a_usb3_pcie_cr_bus_addr(priv, addr);
+	if (ret)
+		return ret;
+
+	regmap_write(priv->regmap, PHY_R4, 0);
+	regmap_write(priv->regmap, PHY_R4, PHY_R4_PHY_CR_READ);
+
+	ret = regmap_read_poll_timeout(priv->regmap, PHY_R5, val,
+				       (val & PHY_R5_PHY_CR_ACK),
+				       5, 1000);
+	if (ret)
+		return ret;
+
+	*data = FIELD_GET(PHY_R5_PHY_CR_DATA_OUT, val);
+
+	regmap_write(priv->regmap, PHY_R4, 0);
+
+	ret = regmap_read_poll_timeout(priv->regmap, PHY_R5, val,
+				       !(val & PHY_R5_PHY_CR_ACK),
+				       5, 1000);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int
+phy_g12a_usb3_pcie_cr_bus_write(struct phy_g12a_usb3_pcie_priv *priv,
+			        unsigned int addr, unsigned int data)
+{
+	unsigned int val, reg;
+	int ret;
+
+	ret = phy_g12a_usb3_pcie_cr_bus_addr(priv, addr);
+	if (ret)
+		return ret;
+
+	reg = FIELD_PREP(PHY_R4_PHY_CR_DATA_IN, data);
+
+	regmap_write(priv->regmap, PHY_R4, reg);
+	regmap_write(priv->regmap, PHY_R4, reg);
+
+	regmap_write(priv->regmap, PHY_R4, reg | PHY_R4_PHY_CR_CAP_DATA);
+
+	ret = regmap_read_poll_timeout(priv->regmap, PHY_R5, val,
+				       (val & PHY_R5_PHY_CR_ACK),
+				       5, 1000);
+	if (ret)
+		return ret;
+
+	regmap_write(priv->regmap, PHY_R4, reg);
+
+	ret = regmap_read_poll_timeout(priv->regmap, PHY_R5, val,
+				       (val & PHY_R5_PHY_CR_ACK) == 0,
+				       5, 1000);
+	if (ret)
+		return ret;
+
+	regmap_write(priv->regmap, PHY_R4, reg);
+
+	regmap_write(priv->regmap, PHY_R4, reg | PHY_R4_PHY_CR_WRITE);
+
+	ret = regmap_read_poll_timeout(priv->regmap, PHY_R5, val,
+				       (val & PHY_R5_PHY_CR_ACK),
+				       5, 1000);
+	if (ret)
+		return ret;
+
+	regmap_write(priv->regmap, PHY_R4, reg);
+
+	ret = regmap_read_poll_timeout(priv->regmap, PHY_R5, val,
+				       (val & PHY_R5_PHY_CR_ACK) == 0,
+				       5, 1000);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int
+phy_g12a_usb3_pcie_cr_bus_update_bits(struct phy_g12a_usb3_pcie_priv *priv,
+				      uint offset, uint mask, uint val)
+{
+	uint reg;
+	int ret;
+
+	ret = phy_g12a_usb3_pcie_cr_bus_read(priv, offset, &reg);
+	if (ret)
+		return ret;
+
+	reg &= ~mask;
+
+	return phy_g12a_usb3_pcie_cr_bus_write(priv, offset, reg | val);
+}
+
+static int phy_meson_g12a_usb3_init(struct phy *phy)
+{
+	struct udevice *dev = phy->dev;
+	struct phy_g12a_usb3_pcie_priv *priv = dev_get_priv(dev);
+	unsigned int data;
+	int ret;
+
+	/* TOFIX Handle PCIE mode */
+
+	ret = reset_assert_bulk(&priv->resets);
+	udelay(1);
+	ret |= reset_deassert_bulk(&priv->resets);
+	if (ret)
+		return ret;
+
+	/* Switch PHY to USB3 */
+	regmap_update_bits(priv->regmap, PHY_R0,
+			   PHY_R0_PCIE_USB3_SWITCH,
+			   PHY_R0_PCIE_USB3_SWITCH);
+
+	/*
+	 * WORKAROUND: There is SSPHY suspend bug due to
+	 * which USB enumerates
+	 * in HS mode instead of SS mode. Workaround it by asserting
+	 * LANE0.TX_ALT_BLOCK.EN_ALT_BUS to enable TX to use alt bus
+	 * mode
+	 */
+	ret = phy_g12a_usb3_pcie_cr_bus_update_bits(priv, 0x102d,
+						    BIT(7), BIT(7));
+	if (ret)
+		return ret;
+
+	ret = phy_g12a_usb3_pcie_cr_bus_update_bits(priv, 0x1010, 0xff0, 20);
+	if (ret)
+		return ret;
+
+	/*
+	 * Fix RX Equalization setting as follows
+	 * LANE0.RX_OVRD_IN_HI. RX_EQ_EN set to 0
+	 * LANE0.RX_OVRD_IN_HI.RX_EQ_EN_OVRD set to 1
+	 * LANE0.RX_OVRD_IN_HI.RX_EQ set to 3
+	 * LANE0.RX_OVRD_IN_HI.RX_EQ_OVRD set to 1
+	 */
+	ret = phy_g12a_usb3_pcie_cr_bus_read(priv, 0x1006, &data);
+	if (ret)
+		return ret;
+
+	data &= ~BIT(6);
+	data |= BIT(7);
+	data &= ~(0x7 << 8);
+	data |= (0x3 << 8);
+	data |= (1 << 11);
+	ret = phy_g12a_usb3_pcie_cr_bus_write(priv, 0x1006, data);
+	if (ret)
+		return ret;
+
+	/*
+	 * Set EQ and TX launch amplitudes as follows
+	 * LANE0.TX_OVRD_DRV_LO.PREEMPH set to 22
+	 * LANE0.TX_OVRD_DRV_LO.AMPLITUDE set to 127
+	 * LANE0.TX_OVRD_DRV_LO.EN set to 1.
+	 */
+	ret = phy_g12a_usb3_pcie_cr_bus_read(priv, 0x1002, &data);
+	if (ret)
+		return ret;
+
+	data &= ~0x3f80;
+	data |= (0x16 << 7);
+	data &= ~0x7f;
+	data |= (0x7f | BIT(14));
+	ret = phy_g12a_usb3_pcie_cr_bus_write(priv, 0x1002, data);
+	if (ret)
+		return ret;
+
+	/*
+	 * MPLL_LOOP_CTL.PROP_CNTRL = 8
+	 */
+	ret = phy_g12a_usb3_pcie_cr_bus_update_bits(priv, 0x30,
+						    0xf << 4, 8 << 4);
+	if (ret)
+		return ret;
+
+	regmap_update_bits(priv->regmap, PHY_R2,
+			PHY_R2_PHY_TX_VBOOST_LVL,
+			FIELD_PREP(PHY_R2_PHY_TX_VBOOST_LVL, 0x4));
+
+	regmap_update_bits(priv->regmap, PHY_R1,
+			PHY_R1_PHY_LOS_BIAS | PHY_R1_PHY_LOS_LEVEL,
+			FIELD_PREP(PHY_R1_PHY_LOS_BIAS, 4) |
+			FIELD_PREP(PHY_R1_PHY_LOS_LEVEL, 9));
+
+	return ret;
+}
+
+static int phy_meson_g12a_usb3_exit(struct phy *phy)
+{
+	struct phy_g12a_usb3_pcie_priv *priv = dev_get_priv(phy->dev);
+
+	return reset_assert_bulk(&priv->resets);
+}
+
+struct phy_ops meson_g12a_usb3_pcie_phy_ops = {
+	.init = phy_meson_g12a_usb3_init,
+	.exit = phy_meson_g12a_usb3_exit,
+};
+
+int meson_g12a_usb3_pcie_phy_probe(struct udevice *dev)
+{
+	struct phy_g12a_usb3_pcie_priv *priv = dev_get_priv(dev);
+	int ret;
+
+	ret = regmap_init_mem(dev_ofnode(dev), &priv->regmap);
+	if (ret)
+		return ret;
+
+	ret = reset_get_bulk(dev, &priv->resets);
+	if (ret == -ENOTSUPP)
+		return 0;
+	else if (ret)
+		return ret;
+
+#if CONFIG_IS_ENABLED(CLK)
+	ret = clk_get_by_index(dev, 0, &priv->clk);
+	if (ret < 0)
+		return ret;
+
+	ret = clk_enable(&priv->clk);
+	if (ret && ret != -ENOENT && ret != -ENOTSUPP) {
+		pr_err("failed to enable PHY clock\n");
+		clk_free(&priv->clk);
+		return ret;
+	}
+#endif
+
+	return 0;
+}
+
+static const struct udevice_id meson_g12a_usb3_pcie_phy_ids[] = {
+	{ .compatible = "amlogic,g12a-usb3-pcie-phy" },
+	{ }
+};
+
+U_BOOT_DRIVER(meson_g12a_usb3_pcie_phy) = {
+	.name = "meson_g12a_usb3_pcie_phy",
+	.id = UCLASS_PHY,
+	.of_match = meson_g12a_usb3_pcie_phy_ids,
+	.probe = meson_g12a_usb3_pcie_phy_probe,
+	.ops = &meson_g12a_usb3_pcie_phy_ops,
+	.priv_auto_alloc_size = sizeof(struct phy_g12a_usb3_pcie_priv),
+};