[PATCH 1/4] phy: Add Qualcomm DWC3 HS/SS PHY driver

[Andy Gross <agross@codeaurora.org>]

This patch adds a new driver for the Qualcomm USB 3.0 PHY that exists on some
Qualcomm platforms.  This driver uses the generic PHY framework and will
interact with the DWC3 controller.

Signed-off-by: Andy Gross <agross@codeaurora.org>
---
 drivers/phy/Kconfig         |  11 +
 drivers/phy/Makefile        |   1 +
 drivers/phy/phy-qcom-dwc3.c | 483 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 495 insertions(+)
 create mode 100644 drivers/phy/phy-qcom-dwc3.c

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index 7eb5859d..f26bfc9 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -305,6 +305,17 @@ config PHY_QCOM_APQ8064_SATA
 	depends on OF
 	select GENERIC_PHY
 
+config PHY_QCOM_DWC3
+	tristate "Qualcomm DWC3 USB PHY support"
+	depends on ARCH_QCOM
+	depends on HAS_IOMEM
+	depends on OF
+	select GENERIC_PHY
+	help
+	  This option enables support for the Synopsis PHYs present inside the
+	  Qualcomm USB3.0 DWC3 controller.  This driver supports both HS and SS
+	  PHY controllers.
+
 config PHY_QCOM_IPQ806X_SATA
 	tristate "Qualcomm IPQ806x SATA SerDes/PHY driver"
 	depends on ARCH_QCOM
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index 075db1a..0610e0d 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -48,3 +48,4 @@ obj-$(CONFIG_PHY_TUSB1210)		+= phy-tusb1210.o
 obj-$(CONFIG_PHY_BRCMSTB_SATA)		+= phy-brcmstb-sata.o
 obj-$(CONFIG_PHY_PISTACHIO_USB)		+= phy-pistachio-usb.o
 obj-$(CONFIG_PHY_CYGNUS_PCIE)		+= phy-bcm-cygnus-pcie.o
+obj-$(CONFIG_PHY_QCOM_DWC3)		+= phy-qcom-dwc3.o
diff --git a/drivers/phy/phy-qcom-dwc3.c b/drivers/phy/phy-qcom-dwc3.c
new file mode 100644
index 0000000..9398f6b
--- /dev/null
+++ b/drivers/phy/phy-qcom-dwc3.c
@@ -0,0 +1,483 @@
+/* Copyright (c) 2014-2015, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/delay.h>
+
+/**
+ *  USB QSCRATCH Hardware registers
+ */
+#define QSCRATCH_GENERAL_CFG		(0x08)
+#define HSUSB_PHY_CTRL_REG		(0x10)
+
+/* PHY_CTRL_REG */
+#define HSUSB_CTRL_DMSEHV_CLAMP			BIT(24)
+#define HSUSB_CTRL_USB2_SUSPEND			BIT(23)
+#define HSUSB_CTRL_UTMI_CLK_EN			BIT(21)
+#define HSUSB_CTRL_UTMI_OTG_VBUS_VALID		BIT(20)
+#define HSUSB_CTRL_USE_CLKCORE			BIT(18)
+#define HSUSB_CTRL_DPSEHV_CLAMP			BIT(17)
+#define HSUSB_CTRL_COMMONONN			BIT(11)
+#define HSUSB_CTRL_ID_HV_CLAMP			BIT(9)
+#define HSUSB_CTRL_OTGSESSVLD_CLAMP		BIT(8)
+#define HSUSB_CTRL_CLAMP_EN			BIT(7)
+#define HSUSB_CTRL_RETENABLEN			BIT(1)
+#define HSUSB_CTRL_POR				BIT(0)
+
+/* QSCRATCH_GENERAL_CFG */
+#define HSUSB_GCFG_XHCI_REV		BIT(2)
+
+/**
+ *  USB QSCRATCH Hardware registers
+ */
+#define SSUSB_PHY_CTRL_REG		(0x00)
+#define SSUSB_PHY_PARAM_CTRL_1		(0x04)
+#define SSUSB_PHY_PARAM_CTRL_2		(0x08)
+#define CR_PROTOCOL_DATA_IN_REG		(0x0c)
+#define CR_PROTOCOL_DATA_OUT_REG	(0x10)
+#define CR_PROTOCOL_CAP_ADDR_REG	(0x14)
+#define CR_PROTOCOL_CAP_DATA_REG	(0x18)
+#define CR_PROTOCOL_READ_REG		(0x1c)
+#define CR_PROTOCOL_WRITE_REG		(0x20)
+
+/* PHY_CTRL_REG */
+#define SSUSB_CTRL_REF_USE_PAD		BIT(28)
+#define SSUSB_CTRL_TEST_POWERDOWN	BIT(27)
+#define SSUSB_CTRL_LANE0_PWR_PRESENT	BIT(24)
+#define SSUSB_CTRL_SS_PHY_EN		BIT(8)
+#define SSUSB_CTRL_SS_PHY_RESET		BIT(7)
+
+/* SSPHY control registers */
+#define SSPHY_CTRL_RX_OVRD_IN_HI(lane)	(0x1006 + 0x100 * lane)
+#define SSPHY_CTRL_TX_OVRD_DRV_LO(lane)	(0x1002 + 0x100 * lane)
+
+/* RX OVRD IN HI bits */
+#define RX_OVRD_IN_HI_RX_RESET_OVRD		BIT(13)
+#define RX_OVRD_IN_HI_RX_RX_RESET		BIT(12)
+#define RX_OVRD_IN_HI_RX_EQ_OVRD		BIT(11)
+#define RX_OVRD_IN_HI_RX_EQ_MASK		0x0700
+#define RX_OVRD_IN_HI_RX_EQ_SHIFT		8
+#define RX_OVRD_IN_HI_RX_EQ_EN_OVRD		BIT(7)
+#define RX_OVRD_IN_HI_RX_EQ_EN			BIT(6)
+#define RX_OVRD_IN_HI_RX_LOS_FILTER_OVRD	BIT(5)
+#define RX_OVRD_IN_HI_RX_LOS_FILTER_MASK	0x0018
+#define RX_OVRD_IN_HI_RX_RATE_OVRD		BIT(2)
+#define RX_OVRD_IN_HI_RX_RATE_MASK		0x0003
+
+/* TX OVRD DRV LO register bits */
+#define TX_OVRD_DRV_LO_AMPLITUDE_MASK	0x007F
+#define TX_OVRD_DRV_LO_PREEMPH_MASK	0x3F80
+#define TX_OVRD_DRV_LO_PREEMPH_SHIFT	7
+#define TX_OVRD_DRV_LO_EN		BIT(14)
+
+/* SS CAP register bits */
+#define SS_CR_CAP_ADDR_REG		BIT(0)
+#define SS_CR_CAP_DATA_REG		BIT(0)
+#define SS_CR_READ_REG			BIT(0)
+#define SS_CR_WRITE_REG			BIT(0)
+
+struct qcom_dwc3_usb_phy {
+	void __iomem		*base;
+	struct device		*dev;
+	struct clk		*xo_clk;
+	struct clk		*ref_clk;
+};
+
+struct qcom_dwc3_phy_drvdata {
+	struct phy_ops	ops;
+	u32		clk_rate;
+};
+
+/**
+ * Write register and read back masked value to confirm it is written
+ *
+ * @base - QCOM DWC3 PHY base virtual address.
+ * @offset - register offset.
+ * @mask - register bitmask specifying what should be updated
+ * @val - value to write.
+ */
+static inline void qcom_dwc3_phy_write_readback(
+	struct qcom_dwc3_usb_phy *phy_dwc3, u32 offset,
+	const u32 mask, u32 val)
+{
+	u32 write_val, tmp = readl(phy_dwc3->base + offset);
+
+	tmp &= ~mask;		/* retain other bits */
+	write_val = tmp | val;
+
+	writel(write_val, phy_dwc3->base + offset);
+
+	/* Read back to see if val was written */
+	tmp = readl(phy_dwc3->base + offset);
+	tmp &= mask;		/* clear other bits */
+
+	if (tmp != val)
+		dev_err(phy_dwc3->dev, "write: %x to QSCRATCH: %x FAILED\n",
+			val, offset);
+}
+
+static int wait_for_latch(void __iomem *addr)
+{
+	u32 retry = 10;
+
+	while (true) {
+		if (!readl(addr))
+			break;
+
+		if (--retry == 0)
+			return -ETIMEDOUT;
+
+		usleep_range(10, 20);
+	}
+
+	return 0;
+}
+
+/**
+ * Write SSPHY register
+ *
+ * @base - QCOM DWC3 PHY base virtual address.
+ * @addr - SSPHY address to write.
+ * @val - value to write.
+ */
+static int qcom_dwc3_ss_write_phycreg(struct qcom_dwc3_usb_phy *phy_dwc3,
+					u32 addr, u32 val)
+{
+	int ret;
+
+	writel(addr, phy_dwc3->base + CR_PROTOCOL_DATA_IN_REG);
+	writel(SS_CR_CAP_ADDR_REG, phy_dwc3->base + CR_PROTOCOL_CAP_ADDR_REG);
+
+	ret = wait_for_latch(phy_dwc3->base + CR_PROTOCOL_CAP_ADDR_REG);
+	if (ret)
+		goto err_wait;
+
+	writel(val, phy_dwc3->base + CR_PROTOCOL_DATA_IN_REG);
+	writel(SS_CR_CAP_DATA_REG, phy_dwc3->base + CR_PROTOCOL_CAP_DATA_REG);
+
+	ret = wait_for_latch(phy_dwc3->base + CR_PROTOCOL_CAP_DATA_REG);
+	if (ret)
+		goto err_wait;
+
+	writel(SS_CR_WRITE_REG, phy_dwc3->base + CR_PROTOCOL_WRITE_REG);
+
+	ret = wait_for_latch(phy_dwc3->base + CR_PROTOCOL_WRITE_REG);
+
+err_wait:
+	dev_err(phy_dwc3->dev, "timeout waiting for latch\n");
+	return ret;
+}
+
+/**
+ * Read SSPHY register.
+ *
+ * @base - QCOM DWC3 PHY base virtual address.
+ * @addr - SSPHY address to read.
+ */
+static int qcom_dwc3_ss_read_phycreg(void __iomem *base, u32 addr, u32 *val)
+{
+	int ret;
+
+	writel(addr, base + CR_PROTOCOL_DATA_IN_REG);
+	writel(SS_CR_CAP_ADDR_REG, base + CR_PROTOCOL_CAP_ADDR_REG);
+
+	ret = wait_for_latch(base + CR_PROTOCOL_CAP_ADDR_REG);
+	if (ret)
+		goto err_wait;
+
+	/*
+	 * Due to hardware bug, first read of SSPHY register might be
+	 * incorrect. Hence as workaround, SW should perform SSPHY register
+	 * read twice, but use only second read and ignore first read.
+	 */
+	writel(SS_CR_READ_REG, base + CR_PROTOCOL_READ_REG);
+
+	ret = wait_for_latch(base + CR_PROTOCOL_READ_REG);
+	if (ret)
+		goto err_wait;
+
+	/* throwaway read */
+	readl(base + CR_PROTOCOL_DATA_OUT_REG);
+
+	writel(SS_CR_READ_REG, base + CR_PROTOCOL_READ_REG);
+
+	ret = wait_for_latch(base + CR_PROTOCOL_READ_REG);
+	if (ret)
+		goto err_wait;
+
+	*val = readl(base + CR_PROTOCOL_DATA_OUT_REG);
+
+err_wait:
+	return ret;
+}
+
+static int qcom_dwc3_phy_power_on(struct phy *phy)
+{
+	int ret;
+	struct qcom_dwc3_usb_phy *phy_dwc3 = phy_get_drvdata(phy);
+
+	ret = clk_prepare_enable(phy_dwc3->xo_clk);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(phy_dwc3->ref_clk);
+	if (ret)
+		clk_disable_unprepare(phy_dwc3->xo_clk);
+
+	return ret;
+}
+
+static int qcom_dwc3_phy_power_off(struct phy *phy)
+{
+	struct qcom_dwc3_usb_phy *phy_dwc3 = phy_get_drvdata(phy);
+
+	clk_disable_unprepare(phy_dwc3->ref_clk);
+	clk_disable_unprepare(phy_dwc3->xo_clk);
+
+	return 0;
+}
+
+static int qcom_dwc3_hs_phy_init(struct phy *phy)
+{
+	struct qcom_dwc3_usb_phy *phy_dwc3 = phy_get_drvdata(phy);
+	u32 val;
+
+	/*
+	 * HSPHY Initialization: Enable UTMI clock, select 19.2MHz fsel
+	 * enable clamping, and disable RETENTION (power-on default is ENABLED)
+	 */
+	val = HSUSB_CTRL_DPSEHV_CLAMP | HSUSB_CTRL_DMSEHV_CLAMP |
+		HSUSB_CTRL_RETENABLEN  | HSUSB_CTRL_COMMONONN |
+		HSUSB_CTRL_OTGSESSVLD_CLAMP | HSUSB_CTRL_ID_HV_CLAMP |
+		HSUSB_CTRL_DPSEHV_CLAMP | HSUSB_CTRL_UTMI_OTG_VBUS_VALID |
+		HSUSB_CTRL_UTMI_CLK_EN | HSUSB_CTRL_CLAMP_EN | 0x70;
+
+	/* use core clock if external reference is not present */
+	if (!phy_dwc3->xo_clk)
+		val |= HSUSB_CTRL_USE_CLKCORE;
+
+	writel(val, phy_dwc3->base + HSUSB_PHY_CTRL_REG);
+	usleep_range(2000, 2200);
+
+	/* Disable (bypass) VBUS and ID filters */
+	writel(HSUSB_GCFG_XHCI_REV, phy_dwc3->base + QSCRATCH_GENERAL_CFG);
+
+	return 0;
+}
+
+static int qcom_dwc3_ss_phy_init(struct phy *phy)
+{
+	struct qcom_dwc3_usb_phy *phy_dwc3 = phy_get_drvdata(phy);
+	int ret;
+	u32 data = 0;
+
+	/* reset phy */
+	data = readl(phy_dwc3->base + SSUSB_PHY_CTRL_REG);
+	writel(data | SSUSB_CTRL_SS_PHY_RESET,
+		phy_dwc3->base + SSUSB_PHY_CTRL_REG);
+	usleep_range(2000, 2200);
+	writel(data, phy_dwc3->base + SSUSB_PHY_CTRL_REG);
+
+	/* clear REF_PAD if we don't have XO clk */
+	if (!phy_dwc3->xo_clk)
+		data &= ~SSUSB_CTRL_REF_USE_PAD;
+	else
+		data |= SSUSB_CTRL_REF_USE_PAD;
+
+	writel(data, phy_dwc3->base + SSUSB_PHY_CTRL_REG);
+
+	/* wait for ref clk to become stable, this can take up to 30ms */
+	msleep(30);
+
+	data |= SSUSB_CTRL_SS_PHY_EN | SSUSB_CTRL_LANE0_PWR_PRESENT;
+	writel(data, phy_dwc3->base + SSUSB_PHY_CTRL_REG);
+
+	/*
+	 * 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 = qcom_dwc3_ss_read_phycreg(phy_dwc3->base,
+			SSPHY_CTRL_RX_OVRD_IN_HI(0), &data);
+	if (ret)
+		goto err_phy_trans;
+
+	data &= ~RX_OVRD_IN_HI_RX_EQ_EN;
+	data |= RX_OVRD_IN_HI_RX_EQ_EN_OVRD;
+	data &= ~RX_OVRD_IN_HI_RX_EQ_MASK;
+	data |= 0x3 << RX_OVRD_IN_HI_RX_EQ_SHIFT;
+	data |= RX_OVRD_IN_HI_RX_EQ_OVRD;
+	ret = qcom_dwc3_ss_write_phycreg(phy_dwc3,
+		SSPHY_CTRL_RX_OVRD_IN_HI(0), data);
+	if (ret)
+		goto err_phy_trans;
+
+	/*
+	 * 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 = qcom_dwc3_ss_read_phycreg(phy_dwc3->base,
+		SSPHY_CTRL_TX_OVRD_DRV_LO(0), &data);
+	if (ret)
+		goto err_phy_trans;
+
+	data &= ~TX_OVRD_DRV_LO_PREEMPH_MASK;
+	data |= 0x16 << TX_OVRD_DRV_LO_PREEMPH_SHIFT;
+	data &= ~TX_OVRD_DRV_LO_AMPLITUDE_MASK;
+	data |= 0x7f;
+	data |= TX_OVRD_DRV_LO_EN;
+	ret = qcom_dwc3_ss_write_phycreg(phy_dwc3,
+		SSPHY_CTRL_TX_OVRD_DRV_LO(0), data);
+	if (ret)
+		goto err_phy_trans;
+
+	/*
+	 * Set the QSCRATCH PHY_PARAM_CTRL1 parameters as follows
+	 * TX_FULL_SWING [26:20] amplitude to 127
+	 * TX_DEEMPH_3_5DB [13:8] to 22
+	 * LOS_BIAS [2:0] to 0x5
+	 */
+	qcom_dwc3_phy_write_readback(phy_dwc3, SSUSB_PHY_PARAM_CTRL_1,
+				   0x07f03f07, 0x07f01605);
+
+err_phy_trans:
+	return ret;
+}
+
+static int qcom_dwc3_ss_phy_exit(struct phy *phy)
+{
+	struct qcom_dwc3_usb_phy *phy_dwc3 = phy_get_drvdata(phy);
+
+	/* Sequence to put SSPHY in low power state:
+	 * 1. Clear REF_PHY_EN in PHY_CTRL_REG
+	 * 2. Clear REF_USE_PAD in PHY_CTRL_REG
+	 * 3. Set TEST_POWERED_DOWN in PHY_CTRL_REG to enable PHY retention
+	 */
+	qcom_dwc3_phy_write_readback(phy_dwc3, SSUSB_PHY_CTRL_REG,
+		SSUSB_CTRL_SS_PHY_EN, 0x0);
+	qcom_dwc3_phy_write_readback(phy_dwc3, SSUSB_PHY_CTRL_REG,
+		SSUSB_CTRL_REF_USE_PAD, 0x0);
+	qcom_dwc3_phy_write_readback(phy_dwc3, SSUSB_PHY_CTRL_REG,
+		0x0, SSUSB_CTRL_TEST_POWERDOWN);
+
+	return 0;
+}
+
+static const struct qcom_dwc3_phy_drvdata qcom_dwc3_hs_drvdata = {
+	.ops = {
+		.init		= qcom_dwc3_hs_phy_init,
+		.power_on	= qcom_dwc3_phy_power_on,
+		.power_off	= qcom_dwc3_phy_power_off,
+		.owner		= THIS_MODULE,
+	},
+	.clk_rate = 60000000,
+};
+
+static const struct qcom_dwc3_phy_drvdata qcom_dwc3_ss_drvdata = {
+	.ops = {
+		.init		= qcom_dwc3_ss_phy_init,
+		.exit		= qcom_dwc3_ss_phy_exit,
+		.power_on	= qcom_dwc3_phy_power_on,
+		.power_off	= qcom_dwc3_phy_power_off,
+		.owner		= THIS_MODULE,
+	},
+	.clk_rate = 125000000,
+};
+
+static const struct of_device_id qcom_dwc3_phy_table[] = {
+	{ .compatible = "qcom,dwc3-hs-usb-phy", .data = &qcom_dwc3_hs_drvdata },
+	{ .compatible = "qcom,dwc3-ss-usb-phy", .data = &qcom_dwc3_ss_drvdata },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, qcom_dwc3_phy_table);
+
+static int qcom_dwc3_phy_probe(struct platform_device *pdev)
+{
+	struct qcom_dwc3_usb_phy	*phy_dwc3;
+	struct phy_provider		*phy_provider;
+	struct phy			*generic_phy;
+	struct resource			*res;
+	const struct of_device_id *match;
+	const struct qcom_dwc3_phy_drvdata *data;
+
+	phy_dwc3 = devm_kzalloc(&pdev->dev, sizeof(*phy_dwc3), GFP_KERNEL);
+	if (!phy_dwc3)
+		return -ENOMEM;
+
+	match = of_match_node(qcom_dwc3_phy_table, pdev->dev.of_node);
+	data = match->data;
+
+	phy_dwc3->dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	phy_dwc3->base = devm_ioremap_resource(phy_dwc3->dev, res);
+	if (IS_ERR(phy_dwc3->base))
+		return PTR_ERR(phy_dwc3->base);
+
+	phy_dwc3->ref_clk = devm_clk_get(phy_dwc3->dev, "ref");
+	if (IS_ERR(phy_dwc3->ref_clk)) {
+		dev_dbg(phy_dwc3->dev, "cannot get reference clock\n");
+		return PTR_ERR(phy_dwc3->ref_clk);
+	}
+
+	clk_set_rate(phy_dwc3->ref_clk, data->clk_rate);
+
+	phy_dwc3->xo_clk = devm_clk_get(phy_dwc3->dev, "xo");
+	if (IS_ERR(phy_dwc3->xo_clk)) {
+		dev_dbg(phy_dwc3->dev, "cannot get TCXO clock\n");
+		phy_dwc3->xo_clk = NULL;
+	}
+
+	generic_phy = devm_phy_create(phy_dwc3->dev, pdev->dev.of_node,
+				      &data->ops);
+
+	if (IS_ERR(generic_phy))
+		return PTR_ERR(generic_phy);
+
+	phy_set_drvdata(generic_phy, phy_dwc3);
+	platform_set_drvdata(pdev, phy_dwc3);
+
+	phy_provider = devm_of_phy_provider_register(phy_dwc3->dev,
+			of_phy_simple_xlate);
+
+	if (IS_ERR(phy_provider))
+		return PTR_ERR(phy_provider);
+
+	return 0;
+}
+
+static struct platform_driver qcom_dwc3_phy_driver = {
+	.probe		= qcom_dwc3_phy_probe,
+	.driver		= {
+		.name	= "qcom-dwc3-usb-phy",
+		.owner	= THIS_MODULE,
+		.of_match_table = qcom_dwc3_phy_table,
+	},
+};
+
+module_platform_driver(qcom_dwc3_phy_driver);
+
+MODULE_ALIAS("platform:phy-qcom-dwc3");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Andy Gross <agross@codeaurora.org>");
+MODULE_AUTHOR("Ivan T. Ivanov <iivanov@mm-sol.com>");
+MODULE_DESCRIPTION("DesignWare USB3 QCOM PHY driver");
-- 
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