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Subject[PATCH v6 2/4] phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips
Date
PHY transceiver driver for QUSB2 phy controller that provides
HighSpeed functionality for DWC3 controller present on
Qualcomm chipsets.

Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
---

Changes since v5:
- Rebased on top of phy grouping series. So the driver now sits in
drivers/phy/qualcomm/
- Removed instances of readl_relaxed() and writel_relaxed(), and using
readl() and writel() instead.
- Replaced regulator handling with regulator_bulk() apis, so that
qusb2_phy_toggle_power() method is completely dropped.
- Removed memory barriers from the driver. Instead, using readl() over
the register to ensure that the write is through to the device.
- Fixed nits about return statement from probe() and qusb2_phy_poweron().

Changes since v4:
- Updated the copyright year to 2017.
- Removed unnecessary of_match_ptr() cast for the match table,
since the driver is compiled for CONFIG_OF.

Changes since v3:
- Added 'Reviewed-by' from Stephen.
- Fixed debug message for qusb2_phy_set_tune2_param().
- Replaced devm_reset_control_get() with devm_reset_control_get_by_index()
since we are requesting only one reset.
- Updated devm_nvmem_cell_get() with a NULL cell id.
- Made error labels more idiomatic.
- Refactored qusb2_setbits() and qusb2_clrbits() a little bit to accept
base address and register offset as two separate arguments.

Changes since v2:
- Removed selecting 'RESET_CONTROLLER' config.
- Added error handling for clk_prepare_enable paths.
- Removed explicitly setting ref_clk rate to 19.2 MHz. Don't need to
do that since 'xo' is modeled as parent to this clock.
- Removed 'ref_clk_src' handling. Driver doesn't need to request and
handle this clock.
- Moved nvmem_cell_get() to probe function.
- Simplified phy pll status handling.
- Using of_device_get_match_data() to get match data.
- Uniformly using lowercase for hex numbers.
- Fixed sparse warnings.
- Using shorter variable names in structure and in functions.
- Handling various comment style shortcomings.

Changes since v1:
- removed reference to clk_enabled/pwr_enabled.
- moved clock and regulator enable code to phy_power_on/off() callbacks.
- fixed return on EPROBE_DEFER in qusb2_phy_probe().
- fixed phy create and phy register ordering.
- removed references to non-lkml links from commit message.
- took care of other minor nits.
- Fixed coccinelle warnings -
'PTR_ERR applied after initialization to constant'
- Addressed review comment, regarding qfprom access for tune2 param value.
This driver is now based on qfprom patch[1] that allows byte access now.

drivers/phy/qualcomm/Kconfig | 10 +
drivers/phy/qualcomm/Makefile | 1 +
drivers/phy/qualcomm/phy-qcom-qusb2.c | 491 ++++++++++++++++++++++++++++++++++
3 files changed, 502 insertions(+)
create mode 100644 drivers/phy/qualcomm/phy-qcom-qusb2.c

diff --git a/drivers/phy/qualcomm/Kconfig b/drivers/phy/qualcomm/Kconfig
index 458d224f18a5..f31f05066da8 100644
--- a/drivers/phy/qualcomm/Kconfig
+++ b/drivers/phy/qualcomm/Kconfig
@@ -15,6 +15,16 @@ config PHY_QCOM_IPQ806X_SATA
depends on OF
select GENERIC_PHY

+config PHY_QCOM_QUSB2
+ tristate "Qualcomm QUSB2 PHY Driver"
+ depends on OF && (ARCH_QCOM || COMPILE_TEST)
+ select GENERIC_PHY
+ help
+ Enable this to support the HighSpeed QUSB2 PHY transceiver for USB
+ controllers on Qualcomm chips. This driver supports the high-speed
+ PHY which is usually paired with either the ChipIdea or Synopsys DWC3
+ USB IPs on MSM SOCs.
+
config PHY_QCOM_UFS
tristate "Qualcomm UFS PHY driver"
depends on OF && ARCH_QCOM
diff --git a/drivers/phy/qualcomm/Makefile b/drivers/phy/qualcomm/Makefile
index 07f7c7896f4d..eed5327a9206 100644
--- a/drivers/phy/qualcomm/Makefile
+++ b/drivers/phy/qualcomm/Makefile
@@ -1,5 +1,6 @@
obj-$(CONFIG_PHY_QCOM_APQ8064_SATA) += phy-qcom-apq8064-sata.o
obj-$(CONFIG_PHY_QCOM_IPQ806X_SATA) += phy-qcom-ipq806x-sata.o
+obj-$(CONFIG_PHY_QCOM_QUSB2) += phy-qcom-qusb2.o
obj-$(CONFIG_PHY_QCOM_UFS) += phy-qcom-ufs.o
obj-$(CONFIG_PHY_QCOM_UFS) += phy-qcom-ufs-qmp-20nm.o
obj-$(CONFIG_PHY_QCOM_UFS) += phy-qcom-ufs-qmp-14nm.o
diff --git a/drivers/phy/qualcomm/phy-qcom-qusb2.c b/drivers/phy/qualcomm/phy-qcom-qusb2.c
new file mode 100644
index 000000000000..2b2b2b5222c4
--- /dev/null
+++ b/drivers/phy/qualcomm/phy-qcom-qusb2.c
@@ -0,0 +1,491 @@
+/*
+ * Copyright (c) 2017, The Linux Foundation. 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/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#define QUSB2PHY_PLL_TEST 0x04
+#define CLK_REF_SEL BIT(7)
+
+#define QUSB2PHY_PLL_TUNE 0x08
+#define QUSB2PHY_PLL_USER_CTL1 0x0c
+#define QUSB2PHY_PLL_USER_CTL2 0x10
+#define QUSB2PHY_PLL_AUTOPGM_CTL1 0x1c
+#define QUSB2PHY_PLL_PWR_CTRL 0x18
+
+#define QUSB2PHY_PLL_STATUS 0x38
+#define PLL_LOCKED BIT(5)
+
+#define QUSB2PHY_PORT_TUNE1 0x80
+#define QUSB2PHY_PORT_TUNE2 0x84
+#define QUSB2PHY_PORT_TUNE3 0x88
+#define QUSB2PHY_PORT_TUNE4 0x8c
+#define QUSB2PHY_PORT_TUNE5 0x90
+#define QUSB2PHY_PORT_TEST2 0x9c
+
+#define QUSB2PHY_PORT_POWERDOWN 0xb4
+#define CLAMP_N_EN BIT(5)
+#define FREEZIO_N BIT(1)
+#define POWER_DOWN BIT(0)
+
+#define QUSB2PHY_REFCLK_ENABLE BIT(0)
+
+#define PHY_CLK_SCHEME_SEL BIT(0)
+
+struct qusb2_phy_init_tbl {
+ unsigned int offset;
+ unsigned int val;
+};
+#define QUSB2_PHY_INIT_CFG(o, v) \
+ { \
+ .offset = o, \
+ .val = v, \
+ }
+
+static const struct qusb2_phy_init_tbl msm8996_init_tbl[] = {
+ QUSB2_PHY_INIT_CFG(QUSB2PHY_PORT_TUNE1, 0xf8),
+ QUSB2_PHY_INIT_CFG(QUSB2PHY_PORT_TUNE2, 0xb3),
+ QUSB2_PHY_INIT_CFG(QUSB2PHY_PORT_TUNE3, 0x83),
+ QUSB2_PHY_INIT_CFG(QUSB2PHY_PORT_TUNE4, 0xc0),
+ QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_TUNE, 0x30),
+ QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_USER_CTL1, 0x79),
+ QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_USER_CTL2, 0x21),
+ QUSB2_PHY_INIT_CFG(QUSB2PHY_PORT_TEST2, 0x14),
+ QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_AUTOPGM_CTL1, 0x9f),
+ QUSB2_PHY_INIT_CFG(QUSB2PHY_PLL_PWR_CTRL, 0x00),
+};
+
+struct qusb2_phy_cfg {
+ const struct qusb2_phy_init_tbl *tbl;
+ /* number of entries in the table */
+ unsigned int tbl_num;
+ /* offset to PHY_CLK_SCHEME register in TCSR map */
+ unsigned int clk_scheme_offset;
+};
+
+static const struct qusb2_phy_cfg msm8996_phy_cfg = {
+ .tbl = msm8996_init_tbl,
+ .tbl_num = ARRAY_SIZE(msm8996_init_tbl),
+};
+
+static const char * const qusb2_phy_vreg_names[] = {
+ "vdd-phy", "vdda-pll", "vdda-phy-dpdm",
+};
+#define QUSB2_NUM_VREGS ARRAY_SIZE(qusb2_phy_vreg_names)
+
+/**
+ * struct qusb2_phy - structure holding qusb2 phy attributes
+ *
+ * @phy: generic phy
+ * @base: iomapped memory space for qubs2 phy
+ *
+ * @cfg_ahb_clk: AHB2PHY interface clock
+ * @ref_clk: phy reference clock
+ * @iface_clk: phy interface clock
+ * @phy_reset: phy reset control
+ * @vregs: regulator supplies bulk data
+ *
+ * @tcsr: TCSR syscon register map
+ * @cell: nvmem cell containing phy tuning value
+ *
+ * @cfg: phy config data
+ * @has_se_clk_scheme: indicate if PHY has single-ended ref clock scheme
+ */
+struct qusb2_phy {
+ struct phy *phy;
+ void __iomem *base;
+
+ struct clk *cfg_ahb_clk;
+ struct clk *ref_clk;
+ struct clk *iface_clk;
+ struct reset_control *phy_reset;
+ struct regulator_bulk_data vregs[QUSB2_NUM_VREGS];
+
+ struct regmap *tcsr;
+ struct nvmem_cell *cell;
+
+ const struct qusb2_phy_cfg *cfg;
+ bool has_se_clk_scheme;
+};
+
+static inline void qusb2_setbits(void __iomem *base, u32 offset, u32 val)
+{
+ u32 reg;
+
+ reg = readl(base + offset);
+ reg |= val;
+ writel(reg, base + offset);
+
+ /* Ensure above write is completed */
+ readl(base + offset);
+}
+
+static inline void qusb2_clrbits(void __iomem *base, u32 offset, u32 val)
+{
+ u32 reg;
+
+ reg = readl(base + offset);
+ reg &= ~val;
+ writel(reg, base + offset);
+
+ /* Ensure above write is completed */
+ readl(base + offset);
+}
+
+static inline void qcom_qusb2_phy_configure(void __iomem *base,
+ const struct qusb2_phy_init_tbl tbl[],
+ int num)
+{
+ int i;
+
+ for (i = 0; i < num; i++)
+ writel(tbl[i].val, base + tbl[i].offset);
+}
+
+/*
+ * Fetches HS Tx tuning value from nvmem and sets the
+ * QUSB2PHY_PORT_TUNE2 register.
+ * For error case, skip setting the value and use the default value.
+ */
+static void qusb2_phy_set_tune2_param(struct qusb2_phy *qphy)
+{
+ struct device *dev = &qphy->phy->dev;
+ u8 *val;
+
+ /*
+ * Read efuse register having TUNE2 parameter's high nibble.
+ * If efuse register shows value as 0x0, or if we fail to find
+ * a valid efuse register settings, then use default value
+ * as 0xB for high nibble that we have already set while
+ * configuring phy.
+ */
+ val = nvmem_cell_read(qphy->cell, NULL);
+ if (IS_ERR(val) || !val[0]) {
+ dev_dbg(dev, "failed to read a valid hs-tx trim value\n");
+ return;
+ }
+
+ /* Fused TUNE2 value is the higher nibble only */
+ qusb2_setbits(qphy->base, QUSB2PHY_PORT_TUNE2, val[0] << 0x4);
+}
+
+static int qusb2_phy_poweron(struct phy *phy)
+{
+ struct qusb2_phy *qphy = phy_get_drvdata(phy);
+ int num = ARRAY_SIZE(qphy->vregs);
+ int ret;
+
+ dev_vdbg(&phy->dev, "%s(): Powering-on QUSB2 phy\n", __func__);
+
+ /* turn on regulator supplies */
+ ret = regulator_bulk_enable(num, qphy->vregs);
+ if (ret)
+ return ret;
+
+ ret = clk_prepare_enable(qphy->iface_clk);
+ if (ret) {
+ dev_err(&phy->dev, "failed to enable iface_clk, %d\n", ret);
+ regulator_bulk_disable(num, qphy->vregs);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int qusb2_phy_poweroff(struct phy *phy)
+{
+ struct qusb2_phy *qphy = phy_get_drvdata(phy);
+
+ clk_disable_unprepare(qphy->iface_clk);
+
+ regulator_bulk_disable(ARRAY_SIZE(qphy->vregs), qphy->vregs);
+
+ return 0;
+}
+
+static int qusb2_phy_init(struct phy *phy)
+{
+ struct qusb2_phy *qphy = phy_get_drvdata(phy);
+ unsigned int val;
+ unsigned int clk_scheme;
+ int ret;
+
+ dev_vdbg(&phy->dev, "%s(): Initializing QUSB2 phy\n", __func__);
+
+ /* enable ahb interface clock to program phy */
+ ret = clk_prepare_enable(qphy->cfg_ahb_clk);
+ if (ret) {
+ dev_err(&phy->dev, "failed to enable cfg ahb clock, %d\n", ret);
+ return ret;
+ }
+
+ /* Perform phy reset */
+ ret = reset_control_assert(qphy->phy_reset);
+ if (ret) {
+ dev_err(&phy->dev, "failed to assert phy_reset, %d\n", ret);
+ goto disable_ahb_clk;
+ }
+
+ /* 100 us delay to keep PHY in reset mode */
+ usleep_range(100, 150);
+
+ ret = reset_control_deassert(qphy->phy_reset);
+ if (ret) {
+ dev_err(&phy->dev, "failed to de-assert phy_reset, %d\n", ret);
+ goto disable_ahb_clk;
+ }
+
+ /* Disable the PHY */
+ qusb2_setbits(qphy->base, QUSB2PHY_PORT_POWERDOWN,
+ CLAMP_N_EN | FREEZIO_N | POWER_DOWN);
+
+ /* save reset value to override reference clock scheme later */
+ val = readl(qphy->base + QUSB2PHY_PLL_TEST);
+
+ qcom_qusb2_phy_configure(qphy->base, qphy->cfg->tbl,
+ qphy->cfg->tbl_num);
+
+ /* Set efuse value for tuning the PHY */
+ qusb2_phy_set_tune2_param(qphy);
+
+ /* Enable the PHY */
+ qusb2_clrbits(qphy->base, QUSB2PHY_PORT_POWERDOWN, POWER_DOWN);
+
+ /* Required to get phy pll lock successfully */
+ usleep_range(150, 160);
+
+ /* Default is single-ended clock on msm8996 */
+ qphy->has_se_clk_scheme = true;
+ /*
+ * read TCSR_PHY_CLK_SCHEME register to check if single-ended
+ * clock scheme is selected. If yes, then disable differential
+ * ref_clk and use single-ended clock, otherwise use differential
+ * ref_clk only.
+ */
+ if (qphy->tcsr) {
+ ret = regmap_read(qphy->tcsr, qphy->cfg->clk_scheme_offset,
+ &clk_scheme);
+ if (ret) {
+ dev_err(&phy->dev, "failed to read clk scheme reg\n");
+ goto assert_phy_reset;
+ }
+
+ /* is it a differential clock scheme ? */
+ if (!(clk_scheme & PHY_CLK_SCHEME_SEL)) {
+ dev_vdbg(&phy->dev, "%s(): select differential clk\n",
+ __func__);
+ qphy->has_se_clk_scheme = false;
+ } else {
+ dev_vdbg(&phy->dev, "%s(): select single-ended clk\n",
+ __func__);
+ }
+ }
+
+ if (!qphy->has_se_clk_scheme) {
+ val &= ~CLK_REF_SEL;
+ ret = clk_prepare_enable(qphy->ref_clk);
+ if (ret) {
+ dev_err(&phy->dev, "failed to enable ref clk, %d\n",
+ ret);
+ goto assert_phy_reset;
+ }
+ } else {
+ val |= CLK_REF_SEL;
+ }
+
+ writel(val, qphy->base + QUSB2PHY_PLL_TEST);
+
+ /* ensure above write is through */
+ readl(qphy->base + QUSB2PHY_PLL_TEST);
+
+ /* Required to get phy pll lock successfully */
+ usleep_range(100, 110);
+
+ val = readb(qphy->base + QUSB2PHY_PLL_STATUS);
+ if (!(val & PLL_LOCKED)) {
+ dev_err(&phy->dev,
+ "QUSB2PHY pll lock failed: status reg = %x\n", val);
+ ret = -EBUSY;
+ goto disable_ref_clk;
+ }
+
+ return 0;
+
+disable_ref_clk:
+ if (!qphy->has_se_clk_scheme)
+ clk_disable_unprepare(qphy->ref_clk);
+assert_phy_reset:
+ reset_control_assert(qphy->phy_reset);
+disable_ahb_clk:
+ clk_disable_unprepare(qphy->cfg_ahb_clk);
+ return ret;
+}
+
+static int qusb2_phy_exit(struct phy *phy)
+{
+ struct qusb2_phy *qphy = phy_get_drvdata(phy);
+
+ /* Disable the PHY */
+ qusb2_setbits(qphy->base, QUSB2PHY_PORT_POWERDOWN,
+ CLAMP_N_EN | FREEZIO_N | POWER_DOWN);
+
+ if (!qphy->has_se_clk_scheme)
+ clk_disable_unprepare(qphy->ref_clk);
+
+ reset_control_assert(qphy->phy_reset);
+
+ clk_disable_unprepare(qphy->cfg_ahb_clk);
+
+ return 0;
+}
+
+static const struct phy_ops qusb2_phy_gen_ops = {
+ .init = qusb2_phy_init,
+ .exit = qusb2_phy_exit,
+ .power_on = qusb2_phy_poweron,
+ .power_off = qusb2_phy_poweroff,
+ .owner = THIS_MODULE,
+};
+
+static const struct of_device_id qusb2_phy_of_match_table[] = {
+ {
+ .compatible = "qcom,msm8996-qusb2-phy",
+ .data = &msm8996_phy_cfg,
+ },
+ { },
+};
+MODULE_DEVICE_TABLE(of, qusb2_phy_of_match_table);
+
+static int qusb2_phy_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct qusb2_phy *qphy;
+ struct phy_provider *phy_provider;
+ struct phy *generic_phy;
+ struct resource *res;
+ int ret, i;
+ int num;
+
+ qphy = devm_kzalloc(dev, sizeof(*qphy), GFP_KERNEL);
+ if (!qphy)
+ return -ENOMEM;
+
+ 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);
+
+ qphy->cfg_ahb_clk = devm_clk_get(dev, "cfg_ahb");
+ if (IS_ERR(qphy->cfg_ahb_clk)) {
+ ret = PTR_ERR(qphy->cfg_ahb_clk);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "failed to get cfg ahb clk, %d\n", ret);
+ return ret;
+ }
+
+ qphy->ref_clk = devm_clk_get(dev, "ref");
+ if (IS_ERR(qphy->ref_clk)) {
+ ret = PTR_ERR(qphy->ref_clk);
+ if (ret != -EPROBE_DEFER)
+ dev_err(dev, "failed to get ref clk, %d\n", ret);
+ return ret;
+ }
+
+ qphy->iface_clk = devm_clk_get(dev, "iface");
+ if (IS_ERR(qphy->iface_clk)) {
+ ret = PTR_ERR(qphy->iface_clk);
+ if (ret == -EPROBE_DEFER)
+ return ret;
+ qphy->iface_clk = NULL;
+ dev_dbg(dev, "failed to get iface clk, %d\n", ret);
+ }
+
+ qphy->phy_reset = devm_reset_control_get_by_index(&pdev->dev, 0);
+ if (IS_ERR(qphy->phy_reset)) {
+ dev_err(dev, "failed to get phy core reset\n");
+ return PTR_ERR(qphy->phy_reset);
+ }
+
+ num = ARRAY_SIZE(qphy->vregs);
+ for (i = 0; i < num; i++)
+ qphy->vregs[i].supply = qusb2_phy_vreg_names[i];
+
+ ret = devm_regulator_bulk_get(dev, num, qphy->vregs);
+ if (ret) {
+ dev_err(dev, "failed to get regulator supplies\n");
+ return ret;
+ }
+
+ /* Get the specific init parameters of QMP phy */
+ qphy->cfg = of_device_get_match_data(dev);
+
+ qphy->tcsr = syscon_regmap_lookup_by_phandle(dev->of_node,
+ "qcom,tcsr-syscon");
+ if (IS_ERR(qphy->tcsr)) {
+ dev_dbg(dev, "failed to lookup TCSR regmap\n");
+ qphy->tcsr = NULL;
+ }
+
+ qphy->cell = devm_nvmem_cell_get(dev, NULL);
+ if (IS_ERR(qphy->cell)) {
+ if (PTR_ERR(qphy->cell) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ qphy->cell = NULL;
+ dev_dbg(dev, "failed to lookup tune2 hstx trim value\n");
+ }
+
+ generic_phy = devm_phy_create(dev, NULL, &qusb2_phy_gen_ops);
+ if (IS_ERR(generic_phy)) {
+ ret = PTR_ERR(generic_phy);
+ dev_err(dev, "failed to create phy, %d\n", ret);
+ return ret;
+ }
+ qphy->phy = generic_phy;
+
+ dev_set_drvdata(dev, qphy);
+ phy_set_drvdata(generic_phy, qphy);
+
+ phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+ if (!IS_ERR(phy_provider))
+ dev_info(dev, "Registered Qcom-QUSB2 phy\n");
+
+ return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static struct platform_driver qusb2_phy_driver = {
+ .probe = qusb2_phy_probe,
+ .driver = {
+ .name = "qcom-qusb2-phy",
+ .of_match_table = qusb2_phy_of_match_table,
+ },
+};
+
+module_platform_driver(qusb2_phy_driver);
+
+MODULE_AUTHOR("Vivek Gautam <vivek.gautam@codeaurora.org>");
+MODULE_DESCRIPTION("Qualcomm QUSB2 PHY driver");
+MODULE_LICENSE("GPL v2");
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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