Date:   Thu, 2 Apr 2020 17:32:35 -0700
From:   Wesley Cheng <wcheng@...eaurora.org>
To:     Manu Gautam <mgautam@...eaurora.org>, agross@...nel.org,
        bjorn.andersson@...aro.org, kishon@...com, robh+dt@...nel.org,
        mark.rutland@....com, p.zabel@...gutronix.de
Cc:     linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH v4 2/4] phy: qcom-snps: Add SNPS USB PHY driver for QCOM
 based SOCs

Hi Manu,

On 4/1/2020 11:43 PM, Manu Gautam wrote:
> 
> On 3/31/2020 1:06 AM, Wesley Cheng wrote:
>> This adds the SNPS FemtoPHY driver used in QCOM SOCs.  There
>> are potentially multiple instances of this UTMI PHY on the
>> SOC, all which can utilize this driver.
>>
>> Signed-off-by: Wesley Cheng <wcheng@...eaurora.org>
>> Reviewed-by: Philipp Zabel <pza@...gutronix.de>
>> ---
>>  drivers/phy/qualcomm/Kconfig             |  10 ++
>>  drivers/phy/qualcomm/Makefile            |   1 +
>>  drivers/phy/qualcomm/phy-qcom-snps-7nm.c | 294 +++++++++++++++++++++++++++++++
>>  3 files changed, 305 insertions(+)
>>  create mode 100644 drivers/phy/qualcomm/phy-qcom-snps-7nm.c
>>
>> diff --git a/drivers/phy/qualcomm/Kconfig b/drivers/phy/qualcomm/Kconfig
>> index e46824d..3158c14 100644
>> --- a/drivers/phy/qualcomm/Kconfig
>> +++ b/drivers/phy/qualcomm/Kconfig
>> @@ -85,6 +85,16 @@ config PHY_QCOM_USB_HS
>>  	  Support for the USB high-speed ULPI compliant phy on Qualcomm
>>  	  chipsets.
>>  
>> +config PHY_QCOM_USB_SNPS_HS_7NM
>> +	tristate "Qualcomm 7nm USB HS PHY module"
> 
> Should we really refer this as 7nm PHY or just femto-v2 PHY? femto-v1 being the
> one that is used on 28nm.
> And we can add this to binding as well -
> 
> - "qcom,usb-snps-femto-v2-phy",
> - "qcom,usb-snps-hs-7nm-phy",
> - "qcom,sm8150-usb-hs-phy",
> 

Thanks for the suggestion.  We were trying to see what the best naming
convention would be as well.

I went and checked again to see if we can use the v1/v2 label, and seems
like its a possibility as the PHY major revision would correspond
accordingly to v1 being applicable to the 28nm Femto PHY and v2 being
applicable to the <=7nm Femto PHY.  I will go and modify the naming for
this driver.

>> +	depends on OF && (ARCH_QCOM || COMPILE_TEST)
>> +	select GENERIC_PHY
>> +	help
>> +	  Enable support for the USB high-speed SNPS phy on Qualcomm 7nm
>> +	  chipsets.  This PHY has differences in the register map compared
>> +	  to the 28nm variant.  The PHY is paired with a Synopsys DWC3 USB
>> +	  controller on MSM SOCs.
>> +
>>  config PHY_QCOM_USB_HSIC
>>  	tristate "Qualcomm USB HSIC ULPI PHY module"
>>  	depends on USB_ULPI_BUS
>> diff --git a/drivers/phy/qualcomm/Makefile b/drivers/phy/qualcomm/Makefile
>> index 283251d..06bdb40 100644
>> --- a/drivers/phy/qualcomm/Makefile
>> +++ b/drivers/phy/qualcomm/Makefile
>> @@ -10,3 +10,4 @@ obj-$(CONFIG_PHY_QCOM_UFS_14NM)		+= phy-qcom-ufs-qmp-14nm.o
>>  obj-$(CONFIG_PHY_QCOM_UFS_20NM)		+= phy-qcom-ufs-qmp-20nm.o
>>  obj-$(CONFIG_PHY_QCOM_USB_HS) 		+= phy-qcom-usb-hs.o
>>  obj-$(CONFIG_PHY_QCOM_USB_HSIC) 	+= phy-qcom-usb-hsic.o
>> +obj-$(CONFIG_PHY_QCOM_USB_SNPS_HS_7NM)		+= phy-qcom-snps-7nm.o
>> diff --git a/drivers/phy/qualcomm/phy-qcom-snps-7nm.c b/drivers/phy/qualcomm/phy-qcom-snps-7nm.c
>> new file mode 100644
>> index 0000000..00a46cd
>> --- /dev/null
>> +++ b/drivers/phy/qualcomm/phy-qcom-snps-7nm.c
>> @@ -0,0 +1,294 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2020, The Linux Foundation. All rights reserved.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/delay.h>
>> +#include <linux/err.h>
>> +#include <linux/io.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.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 USB2_PHY_USB_PHY_UTMI_CTRL0		(0x3c)
>> +#define OPMODE_MASK					GENMASK(4, 3)
>> +#define OPMODE_NORMAL				(0x00)
>> +#define OPMODE_NONDRIVING			BIT(3)
>> +#define SLEEPM						BIT(0)
>> +#define TERMSEL						BIT(5)
>> +
>> +#define USB2_PHY_USB_PHY_UTMI_CTRL1		(0x40)
>> +#define XCVRSEL						BIT(0)
>> +
>> +#define USB2_PHY_USB_PHY_UTMI_CTRL5		(0x50)
>> +#define POR							BIT(1)
>> +
>> +#define USB2_PHY_USB_PHY_HS_PHY_CTRL_COMMON0	(0x54)
>> +#define RETENABLEN							BIT(3)
>> +#define FSEL_MASK							GENMASK(7, 5)
>> +#define FSEL_DEFAULT						(0x3 << 4)
>> +
>> +#define USB2_PHY_USB_PHY_HS_PHY_CTRL_COMMON1	(0x58)
>> +#define VBUSVLDEXTSEL0						BIT(4)
>> +#define PLLBTUNE							BIT(5)
>> +
>> +#define USB2_PHY_USB_PHY_HS_PHY_CTRL_COMMON2	(0x5c)
>> +#define VREGBYPASS							BIT(0)
>> +
>> +#define USB2_PHY_USB_PHY_HS_PHY_CTRL1	(0x60)
>> +#define VBUSVLDEXT0					BIT(0)
>> +
>> +#define USB2_PHY_USB_PHY_HS_PHY_CTRL2	(0x64)
>> +#define USB2_AUTO_RESUME			BIT(0)
>> +#define USB2_SUSPEND_N				BIT(2)
>> +#define USB2_SUSPEND_N_SEL			BIT(3)
>> +
>> +#define USB2_PHY_USB_PHY_CFG0					(0x94)
>> +#define UTMI_PHY_DATAPATH_CTRL_OVERRIDE_EN	BIT(0)
>> +#define UTMI_PHY_CMN_CTRL_OVERRIDE_EN		BIT(1)
>> +
>> +#define USB2_PHY_USB_PHY_REFCLK_CTRL	(0xa0)
>> +#define REFCLK_SEL_MASK				GENMASK(1, 0)
>> +#define REFCLK_SEL_DEFAULT			(0x2 << 0)
>> +
>> +static const char * const qcom_snps_hsphy_vreg_names[] = {
>> +	"vdda-pll", "vdda33", "vdda18",
>> +};
>> +
>> +#define SNPS_HS_NUM_VREGS		ARRAY_SIZE(qcom_snps_hsphy_vreg_names)
>> +
>> +/**
>> + * struct qcom_snps_hsphy - structure holding snps hs 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
>> +
>> + * @phy_initialized: if PHY has been initialized correctly
>> + *
>> + */
>> +struct qcom_snps_hsphy {
>> +	struct phy *phy;
>> +	void __iomem *base;
>> +
>> +	struct clk *cfg_ahb_clk;
>> +	struct clk *ref_clk;
>> +	struct reset_control *phy_reset;
>> +	struct regulator_bulk_data vregs[SNPS_HS_NUM_VREGS];
>> +
>> +	bool phy_initialized;
>> +};
>> +
>> +static inline void qcom_snps_hsphy_write_mask(void __iomem *base, u32 offset,
>> +				    u32 mask, u32 val)
>> +{
>> +	u32 reg;
>> +
>> +	reg = readl(base + offset);
>> +	reg &= ~mask;
>> +	reg |= val & mask;
>> +	writel(reg, base + offset);
>> +
>> +	/* Ensure above write is completed */
>> +	readl(base + offset);
>> +}
>> +
>> +static int qcom_snps_hsphy_init(struct phy *phy)
>> +{
>> +	struct qcom_snps_hsphy *hsphy = phy_get_drvdata(phy);
>> +	int ret;
>> +
>> +	dev_vdbg(&phy->dev, "%s(): Initializing SNPS HS phy\n", __func__);
>> +
>> +	/* turn on regulator supplies */
>> +	ret = regulator_bulk_enable(ARRAY_SIZE(hsphy->vregs), hsphy->vregs);
>> +	if (ret)
>> +		return ret;
>> +
>> +	/* enable ahb interface clock to program phy */
>> +	ret = clk_prepare_enable(hsphy->cfg_ahb_clk);
>> +	if (ret) {
>> +		dev_err(&phy->dev, "failed to enable cfg ahb clock, %d\n", ret);
>> +		goto poweroff_phy;
>> +	}
>> +
>> +	/* Perform phy reset */
>> +	ret = reset_control_assert(hsphy->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(hsphy->phy_reset);
>> +	if (ret) {
>> +		dev_err(&phy->dev, "failed to de-assert phy_reset, %d\n", ret);
>> +		goto disable_ahb_clk;
>> +	}
>> +
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_CFG0,
>> +							UTMI_PHY_CMN_CTRL_OVERRIDE_EN,
>> +							UTMI_PHY_CMN_CTRL_OVERRIDE_EN);
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_UTMI_CTRL5,
>> +							POR, POR);
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL_COMMON0,
>> +							FSEL_MASK, 0);
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL_COMMON1,
>> +					PLLBTUNE, PLLBTUNE);
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_REFCLK_CTRL,
>> +					REFCLK_SEL_DEFAULT, REFCLK_SEL_MASK);
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL_COMMON1,
>> +					VBUSVLDEXTSEL0, VBUSVLDEXTSEL0);
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL1,
>> +					VBUSVLDEXT0, VBUSVLDEXT0);
>> +
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL_COMMON2,
>> +					VREGBYPASS, VREGBYPASS);
>> +
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL2,
>> +					USB2_SUSPEND_N_SEL | USB2_SUSPEND_N,
>> +					USB2_SUSPEND_N_SEL | USB2_SUSPEND_N);
>> +
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_UTMI_CTRL0,
>> +					SLEEPM, SLEEPM);
>> +
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_UTMI_CTRL5,
>> +					POR, 0);
>> +
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_HS_PHY_CTRL2,
>> +					USB2_SUSPEND_N_SEL, 0);
>> +
>> +	qcom_snps_hsphy_write_mask(hsphy->base, USB2_PHY_USB_PHY_CFG0,
>> +					UTMI_PHY_CMN_CTRL_OVERRIDE_EN, 0);
>> +
>> +	hsphy->phy_initialized = true;
>> +
>> +	return 0;
>> +
>> +disable_ahb_clk:
>> +	clk_disable_unprepare(hsphy->cfg_ahb_clk);
>> +poweroff_phy:
>> +	regulator_bulk_disable(ARRAY_SIZE(hsphy->vregs), hsphy->vregs);
>> +
>> +	return ret;
>> +}
>> +
>> +static int qcom_snps_hsphy_exit(struct phy *phy)
>> +{
>> +	struct qcom_snps_hsphy *hsphy = phy_get_drvdata(phy);
>> +
>> +	reset_control_assert(hsphy->phy_reset);
>> +	clk_disable_unprepare(hsphy->cfg_ahb_clk);
>> +	regulator_bulk_disable(ARRAY_SIZE(hsphy->vregs), hsphy->vregs);
>> +	hsphy->phy_initialized = false;
>> +
>> +	return 0;
>> +}
>> +
>> +static const struct phy_ops qcom_snps_hsphy_gen_ops = {
>> +	.init		= qcom_snps_hsphy_init,
>> +	.exit		= qcom_snps_hsphy_exit,
>> +	.owner		= THIS_MODULE,
>> +};
>> +
>> +static const struct of_device_id qcom_snps_hsphy_of_match_table[] = {
>> +	{
>> +		.compatible	= "qcom,sm8150-usb-hs-phy",
>> +	},
>> +	{
>> +		.compatible	= "qcom,usb-snps-hs-7nm-phy",
>> +	},
>> +	{ },
>> +};
>> +MODULE_DEVICE_TABLE(of, qcom_snps_hsphy_of_match_table);
>> +
>> +static int qcom_snps_hsphy_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct qcom_snps_hsphy *hsphy;
>> +	struct phy_provider *phy_provider;
>> +	struct phy *generic_phy;
>> +	struct resource *res;
>> +	int ret, i;
>> +	int num;
>> +
>> +	hsphy = devm_kzalloc(dev, sizeof(*hsphy), GFP_KERNEL);
>> +	if (!hsphy)
>> +		return -ENOMEM;
>> +
>> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> +	hsphy->base = devm_ioremap_resource(dev, res);
>> +	if (IS_ERR(hsphy->base))
>> +		return PTR_ERR(hsphy->base);
>> +
>> +	hsphy->ref_clk = devm_clk_get(dev, "ref");
>> +	if (IS_ERR(hsphy->ref_clk)) {
>> +		ret = PTR_ERR(hsphy->ref_clk);
>> +		if (ret != -EPROBE_DEFER)
>> +			dev_err(dev, "failed to get ref clk, %d\n", ret);
>> +		return ret;
>> +	}
>> +
>> +	hsphy->phy_reset = devm_reset_control_get_exclusive(&pdev->dev, NULL);
>> +	if (IS_ERR(hsphy->phy_reset)) {
>> +		dev_err(dev, "failed to get phy core reset\n");
>> +		return PTR_ERR(hsphy->phy_reset);
>> +	}
>> +
>> +	num = ARRAY_SIZE(hsphy->vregs);
>> +	for (i = 0; i < num; i++)
>> +		hsphy->vregs[i].supply = qcom_snps_hsphy_vreg_names[i];
>> +
>> +	ret = devm_regulator_bulk_get(dev, num, hsphy->vregs);
>> +	if (ret) {
>> +		if (ret != -EPROBE_DEFER)
>> +			dev_err(dev, "failed to get regulator supplies: %d\n",
>> +				ret);
>> +		return ret;
>> +	}
>> +
>> +	generic_phy = devm_phy_create(dev, NULL, &qcom_snps_hsphy_gen_ops);
>> +	if (IS_ERR(generic_phy)) {
>> +		ret = PTR_ERR(generic_phy);
>> +		dev_err(dev, "failed to create phy, %d\n", ret);
>> +		return ret;
>> +	}
>> +	hsphy->phy = generic_phy;
>> +
>> +	dev_set_drvdata(dev, hsphy);
>> +	phy_set_drvdata(generic_phy, hsphy);
>> +
>> +	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
>> +	if (!IS_ERR(phy_provider))
>> +		dev_info(dev, "Registered Qcom-SNPS HS phy\n");
>> +
>> +	return PTR_ERR_OR_ZERO(phy_provider);
>> +}
>> +
>> +static struct platform_driver qcom_snps_hsphy_driver = {
>> +	.probe		= qcom_snps_hsphy_probe,
>> +	.driver = {
>> +		.name	= "qcom-snps-hs-7nm-phy",
>> +		.of_match_table = qcom_snps_hsphy_of_match_table,
>> +	},
>> +};
>> +
>> +module_platform_driver(qcom_snps_hsphy_driver);
>> +
>> +MODULE_DESCRIPTION("Qualcomm 7nm USB HS PHY driver");
>> +MODULE_LICENSE("GPL v2");
> 

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