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Date:   Mon, 24 Apr 2023 12:23:09 +0300
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Subject: Re: [PATCH v5 4/7] phy: starfive: Add JH7110 PCIE 2.0 PHY driver
Content-Language: en-US
To:     Minda Chen <minda.chen@starfivetech.com>,
        Emil Renner Berthing <emil.renner.berthing@canonical.com>,
        Conor Dooley <conor@kernel.org>, Vinod Koul <vkoul@kernel.org>,
        Kishon Vijay Abraham I <kishon@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Pawel Laszczak <pawell@cadence.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Peter Chen <peter.chen@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>
Cc:     devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-phy@lists.infradead.org, linux-usb@vger.kernel.org,
        linux-riscv@lists.infradead.org,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Mason Huo <mason.huo@starfivetech.com>
References: <20230420110052.3182-1-minda.chen@starfivetech.com>
 <20230420110052.3182-5-minda.chen@starfivetech.com>
From:   Roger Quadros <rogerq@kernel.org>
In-Reply-To: <20230420110052.3182-5-minda.chen@starfivetech.com>
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Precedence: bulk


On 20/04/2023 14:00, Minda Chen wrote:
> Add Starfive JH7110 SoC PCIe 2.0 PHY driver support.
> PCIe 2.0 PHY default connect to PCIe controller.
> But pcie0 PHY can connect to USB 3.0 controlller.

s/controlller/controller

> 
> Signed-off-by: Minda Chen <minda.chen@starfivetech.com>
> ---
>  MAINTAINERS                            |   4 +-
>  drivers/phy/starfive/Kconfig           |  11 ++
>  drivers/phy/starfive/Makefile          |   1 +
>  drivers/phy/starfive/phy-jh7110-pcie.c | 202 +++++++++++++++++++++++++
>  4 files changed, 217 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/phy/starfive/phy-jh7110-pcie.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c09ea66dcd5a..8e0f755ba91b 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19968,10 +19968,12 @@ M:	William Qiu <william.qiu@starfivetech.com>
>  S:	Supported
>  F:	Documentation/devicetree/bindings/soc/starfive/starfive,jh7110-syscon.yaml
>  
> -STARFIVE JH71X0 USB PHY DRIVER
> +STARFIVE JH71X0 PCIE AND USB PHY DRIVER
>  M:	Minda Chen <minda.chen@starfivetech.com>
>  S:	Supported
> +F:	Documentation/devicetree/bindings/phy/starfive,jh7110-pcie-phy.yaml
>  F:	Documentation/devicetree/bindings/phy/starfive,jh7110-usb-phy.yaml
> +F:	drivers/phy/starfive/phy-jh7110-pcie.c
>  F:	drivers/phy/starfive/phy-jh7110-usb.c
>  
>  STATIC BRANCH/CALL
> diff --git a/drivers/phy/starfive/Kconfig b/drivers/phy/starfive/Kconfig
> index 2c013c390dee..c21c21d284a6 100644
> --- a/drivers/phy/starfive/Kconfig
> +++ b/drivers/phy/starfive/Kconfig
> @@ -12,6 +12,17 @@ config PHY_STARFIVE_DPHY_RX
>  	  system. If M is selected, the module will be called
>  	  phy-starfive-dphy-rx.
>  
> +config PHY_STARFIVE_JH7110_PCIE
> +	tristate "Starfive JH7110 PCIE 2.0/USB 3.0 PHY support"
> +	depends on USB_SUPPORT

What if system has PCIE and no USB. Then they can't use this PHY
as it cannot be built?

> +	select GENERIC_PHY
> +	select USB_PHY
> +	help
> +	  Enable this to support the StarFive PCIe 2.0 PHY,
> +	  or used as USB 3.0 PHY.
> +	  If M is selected, the module will be called
> +	  phy-jh7110-pcie.ko.
> +
>  config PHY_STARFIVE_JH7110_USB
>  	tristate "Starfive JH7110 USB 2.0 PHY support"
>  	depends on USB_SUPPORT
> diff --git a/drivers/phy/starfive/Makefile b/drivers/phy/starfive/Makefile
> index 176443852f4d..03a55aad53a2 100644
> --- a/drivers/phy/starfive/Makefile
> +++ b/drivers/phy/starfive/Makefile
> @@ -1,3 +1,4 @@
>  # SPDX-License-Identifier: GPL-2.0
>  obj-$(CONFIG_PHY_STARFIVE_DPHY_RX)      += phy-starfive-dphy-rx.o
> +obj-$(CONFIG_PHY_STARFIVE_JH7110_PCIE)	+= phy-jh7110-pcie.o
>  obj-$(CONFIG_PHY_STARFIVE_JH7110_USB)	+= phy-jh7110-usb.o
> diff --git a/drivers/phy/starfive/phy-jh7110-pcie.c b/drivers/phy/starfive/phy-jh7110-pcie.c
> new file mode 100644
> index 000000000000..fe029daef62e
> --- /dev/null
> +++ b/drivers/phy/starfive/phy-jh7110-pcie.c
> @@ -0,0 +1,202 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * StarFive JH7110 PCIe 2.0 PHY driver
> + *
> + * Copyright (C) 2023 StarFive Technology Co., Ltd.
> + * Author: Minda Chen <minda.chen@starfivetech.com>
> + */
> +
> +#include <linux/bits.h>
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +
> +#define PCIE_KVCO_LEVEL_OFF		(0x28)
> +#define PCIE_USB3_PHY_PLL_CTL_OFF	(0x7c)
> +#define PCIE_KVCO_TUNE_SIGNAL_OFF	(0x80)

Brackets not required.

> +#define PCIE_USB3_PHY_ENABLE		BIT(4)
> +#define PHY_KVCO_FINE_TUNE_LEVEL	0x91
> +#define PHY_KVCO_FINE_TUNE_SIGNALS	0xc
> +
> +#define USB_PDRSTN_SPLIT		BIT(17)
> +
> +#define PCIE_PHY_MODE			BIT(20)
> +#define PCIE_PHY_MODE_MASK		GENMASK(21, 20)
> +#define PCIE_USB3_BUS_WIDTH_MASK	GENMASK(3, 2)
> +#define PCIE_USB3_RATE_MASK		GENMASK(6, 5)
> +#define PCIE_USB3_RX_STANDBY_MASK	BIT(7)
> +#define PCIE_USB3_PHY_ENABLE		BIT(4)
> +
> +struct jh7110_pcie_phy {
> +	struct phy *phy;
> +	struct regmap *stg_syscon;
> +	struct regmap *sys_syscon;
> +	void __iomem *regs;
> +	u32 sys_phy_connect;
> +	u32 stg_pcie_mode;
> +	u32 stg_pcie_usb;
> +	enum phy_mode mode;
> +};
> +
> +static int jh7110_usb3_mode_set(struct jh7110_pcie_phy *data)
> +{
> +	if (!data->stg_syscon || !data->sys_syscon) {
> +		dev_info(&data->phy->dev, "don't support usb3 mode\n");

s/don't/doesn't

dev_err()

> +		return -EINVAL;
> +	}
> +
> +	regmap_update_bits(data->stg_syscon, data->stg_pcie_mode,
> +			   PCIE_PHY_MODE_MASK, PCIE_PHY_MODE);
> +	regmap_update_bits(data->stg_syscon, data->stg_pcie_usb,
> +			   PCIE_USB3_BUS_WIDTH_MASK, 0);
> +	regmap_update_bits(data->stg_syscon, data->stg_pcie_usb,
> +			   PCIE_USB3_RATE_MASK, 0);
> +	regmap_update_bits(data->stg_syscon, data->stg_pcie_usb,
> +			   PCIE_USB3_RX_STANDBY_MASK, 0);
> +	regmap_update_bits(data->stg_syscon, data->stg_pcie_usb,
> +			   PCIE_USB3_PHY_ENABLE, PCIE_USB3_PHY_ENABLE);
> +
> +	/* Connect usb 3.0 phy mode */
> +	regmap_update_bits(data->sys_syscon, data->sys_phy_connect,
> +			   USB_PDRSTN_SPLIT, 0);
> +
> +	/* Configuare spread-spectrum mode: down-spread-spectrum */
> +	writel(PCIE_USB3_PHY_ENABLE, data->regs + PCIE_USB3_PHY_PLL_CTL_OFF);
> +
> +	return 0;
> +}
> +
> +static void jh7110_pcie_mode_set(struct jh7110_pcie_phy *phy)
> +{
> +	/* PCIe Multi-PHY PLL KVCO Gain fine tune settings: */
> +	writel(PHY_KVCO_FINE_TUNE_LEVEL, phy->regs + PCIE_KVCO_LEVEL_OFF);
> +	writel(PHY_KVCO_FINE_TUNE_SIGNALS, phy->regs + PCIE_KVCO_TUNE_SIGNAL_OFF);

In cases where PHY can be connected to both USB and PCIe don't you have to
make sure PHY is connected to PCIe controller by setting data->sys_syscon
and data->stg_syscon appropriately?

> +}
> +
> +static int jh7110_pcie_phy_set_mode(struct phy *_phy,
> +				    enum phy_mode mode, int submode)
> +{
> +	struct jh7110_pcie_phy *phy = phy_get_drvdata(_phy);
> +	int ret;
> +
> +	if (mode == phy->mode)
> +		return 0;
> +
> +	switch (mode) {
> +	case PHY_MODE_USB_HOST:
> +	case PHY_MODE_USB_DEVICE:
> +	case PHY_MODE_USB_OTG:
> +		ret = jh7110_usb3_mode_set(phy);
> +		if (ret)
> +			return ret;
> +		break;
> +	case PHY_MODE_PCIE:
> +		jh7110_pcie_mode_set(phy);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	dev_info(&_phy->dev, "Changing phy mode to %d\n", mode);

dev_dbg()?

> +	phy->mode = mode;
> +
> +	return 0;
> +}
> +
> +static int jh7110_pcie_phy_init(struct phy *_phy)
> +{
> +	return 0;
> +}
> +
> +static int jh7110_pcie_phy_exit(struct phy *_phy)
> +{
> +	return 0;
> +}
> +
> +static const struct phy_ops jh7110_pcie_phy_ops = {
> +	.init		= jh7110_pcie_phy_init,
> +	.exit		= jh7110_pcie_phy_exit,

As you are not doing anything in init/exit, you don't have to set them.

> +	.set_mode	= jh7110_pcie_phy_set_mode,
> +	.owner		= THIS_MODULE,
> +};
> +
> +static int jh7110_pcie_phy_probe(struct platform_device *pdev)
> +{
> +	struct jh7110_pcie_phy *phy;
> +	struct device *dev = &pdev->dev;
> +	struct phy_provider *phy_provider;
> +	u32 args[2];
> +
> +	phy = devm_kzalloc(dev, sizeof(*phy), GFP_KERNEL);
> +	if (!phy)
> +		return -ENOMEM;
> +
> +	phy->regs = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(phy->regs))
> +		return PTR_ERR(phy->regs);
> +
> +	phy->phy = devm_phy_create(dev, NULL, &jh7110_pcie_phy_ops);
> +	if (IS_ERR(phy->phy))
> +		return dev_err_probe(dev, PTR_ERR(phy->regs),
> +			"Failed to map phy base\n");
> +
> +	phy->sys_syscon =
> +		syscon_regmap_lookup_by_phandle_args(pdev->dev.of_node,
> +						     "starfive,sys-syscon",
> +						     1, args);
> +
> +	if (!IS_ERR_OR_NULL(phy->sys_syscon))
> +		phy->sys_phy_connect = args[0];
> +	else
> +		phy->sys_syscon = NULL;
> +
> +	phy->stg_syscon =
> +		syscon_regmap_lookup_by_phandle_args(pdev->dev.of_node,
> +						     "starfive,stg-syscon",
> +						     2, args);
> +
> +	if (!IS_ERR_OR_NULL(phy->stg_syscon)) {
> +		phy->stg_pcie_mode = args[0];
> +		phy->stg_pcie_usb = args[1];
> +	} else {
> +		phy->stg_syscon = NULL;
> +	}
> +
> +	platform_set_drvdata(pdev, phy);
> +	phy_set_drvdata(phy->phy, phy);
> +	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
> +
> +	return PTR_ERR_OR_ZERO(phy_provider);
> +}
> +
> +static int jh7110_pcie_phy_remove(struct platform_device *pdev)
> +{
> +	platform_set_drvdata(pdev, NULL);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id jh7110_pcie_phy_of_match[] = {
> +	{ .compatible = "starfive,jh7110-pcie-phy" },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, jh7110_pcie_phy_of_match);
> +
> +static struct platform_driver jh7110_pcie_phy_driver = {
> +	.probe	= jh7110_pcie_phy_probe,
> +	.remove	= jh7110_pcie_phy_remove,
> +	.driver = {
> +		.of_match_table	= jh7110_pcie_phy_of_match,
> +		.name  = "jh7110-pcie-phy",
> +	}
> +};
> +module_platform_driver(jh7110_pcie_phy_driver);
> +
> +MODULE_DESCRIPTION("StarFive JH7110 PCIe 2.0 PHY driver");
> +MODULE_AUTHOR("Minda Chen <minda.chen@starfivetech.com>");
> +MODULE_LICENSE("GPL");

cheers,
-roger