phy: qcom: Add Qualcomm PCIe2 PHY driver

The Qualcomm PCIe2 PHY is based on design from Synopsys and found in
several different platforms where the QMP PHY isn't used.

Reviewed-by: Niklas Cassel <[e-mail]>
Signed-off-by: Bjorn Andersson <[e-mail]>
Signed-off-by: Kishon Vijay Abraham I <[e-mail]>

drivers/phy/qualcomm/Kconfig

···
 	depends on OF
 	select GENERIC_PHY
 
+config PHY_QCOM_PCIE2
+	tristate "Qualcomm PCIe Gen2 PHY Driver"
+	depends on OF && COMMON_CLK && (ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Enable this to support the Qualcomm PCIe PHY, used with the Synopsys
+	  based PCIe controller.
+
 config PHY_QCOM_QMP
 	tristate "Qualcomm QMP PHY Driver"
 	depends on OF && COMMON_CLK && (ARCH_QCOM || COMPILE_TEST)

drivers/phy/qualcomm/Makefile

···
 obj-$(CONFIG_PHY_ATH79_USB)		+= phy-ath79-usb.o
 obj-$(CONFIG_PHY_QCOM_APQ8064_SATA)	+= phy-qcom-apq8064-sata.o
 obj-$(CONFIG_PHY_QCOM_IPQ806X_SATA)	+= phy-qcom-ipq806x-sata.o
+obj-$(CONFIG_PHY_QCOM_PCIE2)		+= phy-qcom-pcie2.o
 obj-$(CONFIG_PHY_QCOM_QMP)		+= phy-qcom-qmp.o
 obj-$(CONFIG_PHY_QCOM_QUSB2)		+= phy-qcom-qusb2.o
 obj-$(CONFIG_PHY_QCOM_UFS)		+= phy-qcom-ufs.o

drivers/phy/qualcomm/phy-qcom-pcie2.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2014-2017, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2019, Linaro Ltd.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#include <dt-bindings/phy/phy.h>
+
+#define PCIE20_PARF_PHY_STTS         0x3c
+#define PCIE2_PHY_RESET_CTRL         0x44
+#define PCIE20_PARF_PHY_REFCLK_CTRL2 0xa0
+#define PCIE20_PARF_PHY_REFCLK_CTRL3 0xa4
+#define PCIE20_PARF_PCS_SWING_CTRL1  0x88
+#define PCIE20_PARF_PCS_SWING_CTRL2  0x8c
+#define PCIE20_PARF_PCS_DEEMPH1      0x74
+#define PCIE20_PARF_PCS_DEEMPH2      0x78
+#define PCIE20_PARF_PCS_DEEMPH3      0x7c
+#define PCIE20_PARF_CONFIGBITS       0x84
+#define PCIE20_PARF_PHY_CTRL3        0x94
+#define PCIE20_PARF_PCS_CTRL         0x80
+
+#define TX_AMP_VAL                   120
+#define PHY_RX0_EQ_GEN1_VAL          0
+#define PHY_RX0_EQ_GEN2_VAL          4
+#define TX_DEEMPH_GEN1_VAL           24
+#define TX_DEEMPH_GEN2_3_5DB_VAL     26
+#define TX_DEEMPH_GEN2_6DB_VAL       36
+#define PHY_TX0_TERM_OFFST_VAL       0
+
+struct qcom_phy {
+	struct device *dev;
+	void __iomem *base;
+
+	struct regulator_bulk_data vregs[2];
+
+	struct reset_control *phy_reset;
+	struct reset_control *pipe_reset;
+	struct clk *pipe_clk;
+};
+
+static int qcom_pcie2_phy_init(struct phy *phy)
+{
+	struct qcom_phy *qphy = phy_get_drvdata(phy);
+	int ret;
+
+	ret = reset_control_deassert(qphy->phy_reset);
+	if (ret) {
+		dev_err(qphy->dev, "cannot deassert pipe reset\n");
+		return ret;
+	}
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(qphy->vregs), qphy->vregs);
+	if (ret)
+		reset_control_assert(qphy->phy_reset);
+
+	return ret;
+}
+
+static int qcom_pcie2_phy_power_on(struct phy *phy)
+{
+	struct qcom_phy *qphy = phy_get_drvdata(phy);
+	int ret;
+	u32 val;
+
+	/* Program REF_CLK source */
+	val = readl(qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
+	val &= ~BIT(1);
+	writel(val, qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
+
+	usleep_range(1000, 2000);
+
+	/* Don't use PAD for refclock */
+	val = readl(qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
+	val &= ~BIT(0);
+	writel(val, qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL2);
+
+	/* Program SSP ENABLE */
+	val = readl(qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL3);
+	val |= BIT(0);
+	writel(val, qphy->base + PCIE20_PARF_PHY_REFCLK_CTRL3);
+
+	usleep_range(1000, 2000);
+
+	/* Assert Phy SW Reset */
+	val = readl(qphy->base + PCIE2_PHY_RESET_CTRL);
+	val |= BIT(0);
+	writel(val, qphy->base + PCIE2_PHY_RESET_CTRL);
+
+	/* Program Tx Amplitude */
+	val = readl(qphy->base + PCIE20_PARF_PCS_SWING_CTRL1);
+	val &= ~0x7f;
+	val |= TX_AMP_VAL;
+	writel(val, qphy->base + PCIE20_PARF_PCS_SWING_CTRL1);
+
+	val = readl(qphy->base + PCIE20_PARF_PCS_SWING_CTRL2);
+	val &= ~0x7f;
+	val |= TX_AMP_VAL;
+	writel(val, qphy->base + PCIE20_PARF_PCS_SWING_CTRL2);
+
+	/* Program De-Emphasis */
+	val = readl(qphy->base + PCIE20_PARF_PCS_DEEMPH1);
+	val &= ~0x3f;
+	val |= TX_DEEMPH_GEN2_6DB_VAL;
+	writel(val, qphy->base + PCIE20_PARF_PCS_DEEMPH1);
+
+	val = readl(qphy->base + PCIE20_PARF_PCS_DEEMPH2);
+	val &= ~0x3f;
+	val |= TX_DEEMPH_GEN2_3_5DB_VAL;
+	writel(val, qphy->base + PCIE20_PARF_PCS_DEEMPH2);
+
+	val = readl(qphy->base + PCIE20_PARF_PCS_DEEMPH3);
+	val &= ~0x3f;
+	val |= TX_DEEMPH_GEN1_VAL;
+	writel(val, qphy->base + PCIE20_PARF_PCS_DEEMPH3);
+
+	/* Program Rx_Eq */
+	val = readl(qphy->base + PCIE20_PARF_CONFIGBITS);
+	val &= ~0x7;
+	val |= PHY_RX0_EQ_GEN2_VAL;
+	writel(val, qphy->base + PCIE20_PARF_CONFIGBITS);
+
+	/* Program Tx0_term_offset */
+	val = readl(qphy->base + PCIE20_PARF_PHY_CTRL3);
+	val &= ~0x1f;
+	val |= PHY_TX0_TERM_OFFST_VAL;
+	writel(val, qphy->base + PCIE20_PARF_PHY_CTRL3);
+
+	/* disable Tx2Rx Loopback */
+	val = readl(qphy->base + PCIE20_PARF_PCS_CTRL);
+	val &= ~BIT(1);
+	writel(val, qphy->base + PCIE20_PARF_PCS_CTRL);
+
+	/* De-assert Phy SW Reset */
+	val = readl(qphy->base + PCIE2_PHY_RESET_CTRL);
+	val &= ~BIT(0);
+	writel(val, qphy->base + PCIE2_PHY_RESET_CTRL);
+
+	usleep_range(1000, 2000);
+
+	ret = reset_control_deassert(qphy->pipe_reset);
+	if (ret) {
+		dev_err(qphy->dev, "cannot deassert pipe reset\n");
+		goto out;
+	}
+
+	clk_set_rate(qphy->pipe_clk, 250000000);
+
+	ret = clk_prepare_enable(qphy->pipe_clk);
+	if (ret) {
+		dev_err(qphy->dev, "failed to enable pipe clock\n");
+		goto out;
+	}
+
+	ret = readl_poll_timeout(qphy->base + PCIE20_PARF_PHY_STTS, val,
+				 !(val & BIT(0)), 1000, 10);
+	if (ret)
+		dev_err(qphy->dev, "phy initialization failed\n");
+
+out:
+	return ret;
+}
+
+static int qcom_pcie2_phy_power_off(struct phy *phy)
+{
+	struct qcom_phy *qphy = phy_get_drvdata(phy);
+	u32 val;
+
+	val = readl(qphy->base + PCIE2_PHY_RESET_CTRL);
+	val |= BIT(0);
+	writel(val, qphy->base + PCIE2_PHY_RESET_CTRL);
+
+	clk_disable_unprepare(qphy->pipe_clk);
+	reset_control_assert(qphy->pipe_reset);
+
+	return 0;
+}
+
+static int qcom_pcie2_phy_exit(struct phy *phy)
+{
+	struct qcom_phy *qphy = phy_get_drvdata(phy);
+
+	regulator_bulk_disable(ARRAY_SIZE(qphy->vregs), qphy->vregs);
+	reset_control_assert(qphy->phy_reset);
+
+	return 0;
+}
+
+static const struct phy_ops qcom_pcie2_ops = {
+	.init = qcom_pcie2_phy_init,
+	.power_on = qcom_pcie2_phy_power_on,
+	.power_off = qcom_pcie2_phy_power_off,
+	.exit = qcom_pcie2_phy_exit,
+	.owner = THIS_MODULE,
+};
+
+/*
+ * Register a fixed rate pipe clock.
+ *
+ * The <s>_pipe_clksrc generated by PHY goes to the GCC that gate
+ * controls it. The <s>_pipe_clk coming out of the GCC is requested
+ * by the PHY driver for its operations.
+ * We register the <s>_pipe_clksrc here. The gcc driver takes care
+ * of assigning this <s>_pipe_clksrc as parent to <s>_pipe_clk.
+ * Below picture shows this relationship.
+ *
+ *         +---------------+
+ *         |   PHY block   |<<---------------------------------------+
+ *         |               |                                         |
+ *         |   +-------+   |                   +-----+               |
+ *   I/P---^-->|  PLL  |---^--->pipe_clksrc--->| GCC |--->pipe_clk---+
+ *    clk  |   +-------+   |                   +-----+
+ *         +---------------+
+ */
+static int phy_pipe_clksrc_register(struct qcom_phy *qphy)
+{
+	struct device_node *np = qphy->dev->of_node;
+	struct clk_fixed_rate *fixed;
+	struct clk_init_data init = { };
+	int ret;
+
+	ret = of_property_read_string(np, "clock-output-names", &init.name);
+	if (ret) {
+		dev_err(qphy->dev, "%s: No clock-output-names\n", np->name);
+		return ret;
+	}
+
+	fixed = devm_kzalloc(qphy->dev, sizeof(*fixed), GFP_KERNEL);
+	if (!fixed)
+		return -ENOMEM;
+
+	init.ops = &clk_fixed_rate_ops;
+
+	/* controllers using QMP phys use 250MHz pipe clock interface */
+	fixed->fixed_rate = 250000000;
+	fixed->hw.init = &init;
+
+	return devm_clk_hw_register(qphy->dev, &fixed->hw);
+}
+
+static int qcom_pcie2_phy_probe(struct platform_device *pdev)
+{
+	struct phy_provider *phy_provider;
+	struct qcom_phy *qphy;
+	struct resource *res;
+	struct device *dev = &pdev->dev;
+	struct phy *phy;
+	int ret;
+
+	qphy = devm_kzalloc(dev, sizeof(*qphy), GFP_KERNEL);
+	if (!qphy)
+		return -ENOMEM;
+
+	qphy->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	qphy->base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(qphy->base))
+		return PTR_ERR(qphy->base);
+
+	ret = phy_pipe_clksrc_register(qphy);
+	if (ret) {
+		dev_err(dev, "failed to register pipe_clk\n");
+		return ret;
+	}
+
+	qphy->vregs[0].supply = "vdda-vp";
+	qphy->vregs[1].supply = "vdda-vph";
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(qphy->vregs), qphy->vregs);
+	if (ret < 0)
+		return ret;
+
+	qphy->pipe_clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(qphy->pipe_clk)) {
+		dev_err(dev, "failed to acquire pipe clock\n");
+		return PTR_ERR(qphy->pipe_clk);
+	}
+
+	qphy->phy_reset = devm_reset_control_get_exclusive(dev, "phy");
+	if (IS_ERR(qphy->phy_reset)) {
+		dev_err(dev, "failed to acquire phy reset\n");
+		return PTR_ERR(qphy->phy_reset);
+	}
+
+	qphy->pipe_reset = devm_reset_control_get_exclusive(dev, "pipe");
+	if (IS_ERR(qphy->pipe_reset)) {
+		dev_err(dev, "failed to acquire pipe reset\n");
+		return PTR_ERR(qphy->pipe_reset);
+	}
+
+	phy = devm_phy_create(dev, dev->of_node, &qcom_pcie2_ops);
+	if (IS_ERR(phy)) {
+		dev_err(dev, "failed to create phy\n");
+		return PTR_ERR(phy);
+	}
+
+	phy_set_drvdata(phy, qphy);
+
+	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+	if (IS_ERR(phy_provider))
+		dev_err(dev, "failed to register phy provider\n");
+
+	return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id qcom_pcie2_phy_match_table[] = {
+	{ .compatible = "qcom,pcie2-phy" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, qcom_pcie2_phy_match_table);
+
+static struct platform_driver qcom_pcie2_phy_driver = {
+	.probe = qcom_pcie2_phy_probe,
+	.driver = {
+		.name = "phy-qcom-pcie2",
+		.of_match_table = qcom_pcie2_phy_match_table,
+	},
+};
+
+module_platform_driver(qcom_pcie2_phy_driver);
+
+MODULE_DESCRIPTION("Qualcomm PCIe PHY driver");
+MODULE_LICENSE("GPL v2");