Re: [PATCH v1 2/2] usb: phy: Add USB3 PHY support for Intel LGM SoC

[Philipp Zabel <p.zabel@pengutronix.de>]

Hi Ramuthevar,

On Tue, 2020-06-09 at 19:08 +0800, Ramuthevar,Vadivel MuruganX wrote:
> From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
> 
> Add support for USB PHY on Intel LGM SoC.
> 
> Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
> ---
>  drivers/usb/phy/Kconfig       |  11 ++
>  drivers/usb/phy/Makefile      |   1 +
>  drivers/usb/phy/phy-lgm-usb.c | 269 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 281 insertions(+)
>  create mode 100644 drivers/usb/phy/phy-lgm-usb.c
> 
> diff --git a/drivers/usb/phy/Kconfig b/drivers/usb/phy/Kconfig
> index 4b3fa78995cf..95f2e737d663 100644
> --- a/drivers/usb/phy/Kconfig
> +++ b/drivers/usb/phy/Kconfig
> @@ -192,4 +192,15 @@ config JZ4770_PHY
>  	  This driver provides PHY support for the USB controller found
>  	  on the JZ4770 SoC from Ingenic.
>  
> +config USB_LGM_PHY
> +	tristate "INTEL Lightning Mountain USB PHY Driver"
> +	depends on USB_SUPPORT
> +	select USB_PHY
> +	select REGULATOR
> +	select REGULATOR_FIXED_VOLTAGE
> +	help
> +	  Enable this to support Intel DWC3 PHY USB phy. This driver provides
> +	  interface to interact with USB GEN-II and USB 3.x PHY that is part
> +	  of the Intel network SOC.
> +
>  endmenu
> diff --git a/drivers/usb/phy/Makefile b/drivers/usb/phy/Makefile
> index b352bdbe8712..ef5345164e10 100644
> --- a/drivers/usb/phy/Makefile
> +++ b/drivers/usb/phy/Makefile
> @@ -25,3 +25,4 @@ obj-$(CONFIG_USB_ULPI)			+= phy-ulpi.o
>  obj-$(CONFIG_USB_ULPI_VIEWPORT)		+= phy-ulpi-viewport.o
>  obj-$(CONFIG_KEYSTONE_USB_PHY)		+= phy-keystone.o
>  obj-$(CONFIG_JZ4770_PHY)		+= phy-jz4770.o
> +obj-$(CONFIG_USB_LGM_PHY)		+= phy-lgm-usb.o
> diff --git a/drivers/usb/phy/phy-lgm-usb.c b/drivers/usb/phy/phy-lgm-usb.c
> new file mode 100644
> index 000000000000..66cb327b7b71
> --- /dev/null
> +++ b/drivers/usb/phy/phy-lgm-usb.c
> @@ -0,0 +1,269 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Intel LGM USB PHY driver
> + *
> + * Copyright (C) 2020 Intel Corporation.
> + */
> +
> +#include <linux/bitfield.h>
> +#include <linux/delay.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/reset.h>
> +#include <linux/usb/phy.h>
> +#include <linux/workqueue.h>
> +
> +#define CTRL1_OFFSET		0x14
> +#define SRAM_EXT_LD_DONE	BIT(25)
> +#define SRAM_INIT_DONE		BIT(26)
> +
> +#define TCPC_OFFSET		0x1014
> +#define TCPC_MUX_CTL		GENMASK(1, 0)
> +#define MUX_NC			0
> +#define MUX_USB			1
> +#define MUX_DP			2
> +#define MUX_USBDP		3
> +#define TCPC_FLIPPED		BIT(2)
> +#define TCPC_LOW_POWER_EN	BIT(3)
> +#define TCPC_VALID		BIT(4)
> +#define TCPC_DISCONN		\
> +	(TCPC_VALID | FIELD_PREP(TCPC_MUX_CTL, MUX_NC) | TCPC_LOW_POWER_EN)
> +
> +static const char *const PHY_RESETS[] = { "phy31", "phy", };
> +static const char *const CTL_RESETS[] = { "apb", "ctrl", };
> +
> +struct tca_apb {
> +	struct reset_control *resets[ARRAY_SIZE(PHY_RESETS)];
> +	struct regulator *vbus;
> +	struct work_struct wk;
> +	struct usb_phy phy;
> +
> +	bool phy_initialized;
> +	bool connected;
> +};
> +
> +static int get_flipped(struct tca_apb *ta, bool *flipped)
> +{
> +	union extcon_property_value property;
> +	int ret;
> +
> +	ret = extcon_get_property(ta->phy.edev, EXTCON_USB_HOST,
> +				  EXTCON_PROP_USB_TYPEC_POLARITY, &property);
> +	if (ret) {
> +		dev_err(ta->phy.dev, "no polarity property from extcon\n");
> +		return false;
> +	}
> +
> +	*flipped = property.intval;
> +
> +	return *flipped;
> +}
> +
> +static int phy_init(struct usb_phy *phy)
> +{
> +	struct tca_apb *ta = container_of(phy, struct tca_apb, phy);
> +	void __iomem *ctrl1 = phy->io_priv + CTRL1_OFFSET;
> +	int val, ret, i;
> +
> +	if (ta->phy_initialized)
> +		return 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++)
> +		reset_control_deassert(ta->resets[i]);
> +
> +	ret = readl_poll_timeout(ctrl1, val, val & SRAM_INIT_DONE,
> +				 10, 10 * 1000);
> +	if (IS_ERR(ret)) {
> +		dev_err(ta->phy.dev, "SRAM init failed, 0x%x\n", val);
> +		return PTR_ERR(ret);
> +	}
> +
> +	writel(readl(ctrl1) | SRAM_EXT_LD_DONE, ctrl1);
> +
> +	ta->phy_initialized = true;
> +	if (!ta->phy.edev)
> +		return phy->set_vbus(phy, true);
> +
> +	schedule_work(&ta->wk);
> +
> +	return 0;
> +}
> +
> +static void phy_shutdown(struct usb_phy *phy)
> +{
> +	struct tca_apb *ta = container_of(phy, struct tca_apb, phy);
> +	int i;
> +
> +	if (!ta->phy_initialized)
> +		return;
> +
> +	ta->phy_initialized = false;
> +	flush_work(&ta->wk);
> +	ta->phy.set_vbus(&ta->phy, false);
> +	if (ta->connected) {
> +		ta->connected = false;
> +		writel(TCPC_DISCONN, ta->phy.io_priv + TCPC_OFFSET);
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++)
> +		reset_control_assert(ta->resets[i]);
> +}
> +
> +static int phy_set_vbus(struct usb_phy *phy, int on)
> +{
> +	struct tca_apb *ta = container_of(phy, struct tca_apb, phy);
> +	int ret = 0;
> +
> +	if (on) {
> +		ret = regulator_enable(ta->vbus);
> +		if (ret)
> +			dev_err(ta->phy.dev, "regulator not enabled\n");
> +	} else {
> +		ret = regulator_disable(ta->vbus);
> +		if (ret)
> +			dev_err(ta->phy.dev, "regulator not disabled\n");
> +	}
> +
> +	return ret;
> +}
> +
> +static void tca_work(struct work_struct *work)
> +{
> +	struct tca_apb *ta = container_of(work, struct tca_apb, wk);
> +	union extcon_property_value property;
> +	bool connected;
> +	bool flipped;
> +	u32 val;
> +	int ret;
> +
> +	ret = get_flipped(ta, &flipped);
> +	if (!ret)
> +		dev_err(ta->phy.dev, "no polarity property from extcon\n");
> +
> +	connected = extcon_get_state(ta->phy.edev, EXTCON_USB_HOST);
> +	if (connected == ta->connected)
> +		return;
> +
> +	ta->connected = connected;
> +	if (connected) {
> +		val = TCPC_VALID | FIELD_PREP(TCPC_MUX_CTL, MUX_USB);
> +		if (flipped)
> +			val |= TCPC_FLIPPED;
> +		dev_info(ta->phy.dev, "connected%s\n", flipped ? " flipped" : "");
> +	} else {
> +		val = TCPC_DISCONN;
> +		dev_info(ta->phy.dev, "disconnected\n");
> +	}
> +
> +	writel(val, ta->phy.io_priv + TCPC_OFFSET);
> +
> +	if (ta->phy.set_vbus(&ta->phy, connected))
> +		dev_err(ta->phy.dev, "failed to set VBUS\n");
> +}
> +
> +static int id_notifier(struct notifier_block *nb, unsigned long event, void *ptr)
> +{
> +	struct tca_apb *ta = container_of(nb, struct tca_apb, phy.id_nb);
> +
> +	if (ta->phy_initialized)
> +		schedule_work(&ta->wk);
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static int vbus_notifier(struct notifier_block *nb, unsigned long event, void *ptr)
> +{
> +	return NOTIFY_DONE;
> +}
> +
> +static int phy_probe(struct platform_device *pdev)
> +{
> +	struct reset_control *resets[ARRAY_SIZE(CTL_RESETS)];
> +	struct device *dev = &pdev->dev;
> +	struct usb_phy *phy;
> +	struct tca_apb *ta;
> +	int i;
> +
> +	ta = devm_kzalloc(dev, sizeof(*ta), GFP_KERNEL);
> +	if (!ta)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, ta);
> +	INIT_WORK(&ta->wk, tca_work);
> +
> +	phy = &ta->phy;
> +	phy->dev = dev;
> +	phy->label = dev_name(dev);
> +	phy->type = USB_PHY_TYPE_USB3;
> +	phy->init = phy_init;
> +	phy->shutdown = phy_shutdown;
> +	phy->set_vbus = phy_set_vbus;
> +	phy->id_nb.notifier_call = id_notifier;
> +	phy->vbus_nb.notifier_call = vbus_notifier;
> +
> +	phy->io_priv = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(phy->io_priv))
> +		return PTR_ERR(phy->io_priv);
> +
> +	ta->vbus = devm_regulator_get(dev, "vbus");
> +	if (IS_ERR(ta->vbus))
> +		return PTR_ERR(ta->vbus);
> +
> +	for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++) {
> +		resets[i] = devm_reset_control_get(dev, CTL_RESETS[i]);

Please use devm_reset_control_get_exclusive() instead.

> +		if (IS_ERR(resets[i])) {
> +			dev_err(dev, "%s reset not found\n", CTL_RESETS[i]);
> +			return PTR_ERR(resets[i]);
> +		}
> +		reset_control_assert(resets[i]);
> +	}

You should request all reset controls first, and only then start
asserting / deasserting, otherwise you may end up with partially
asserted resets in case a later reset control is not found.

> +
> +	for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++) {
> +		ta->resets[i] = devm_reset_control_get(dev, PHY_RESETS[i]);

Same as above.

> +		if (IS_ERR(ta->resets[i])) {
> +			dev_err(dev, "%s reset not found\n", PHY_RESETS[i]);
> +			return PTR_ERR(ta->resets[i]);
> +		}
> +		reset_control_assert(ta->resets[i]);
> +	}
> +
> +	for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++)
> +		reset_control_deassert(resets[i]);
> +	/* Need to wait at least 20us before de-assert the PHY */
> +	usleep_range(20, 100);

This waits 20us after de-asserting the reset, not before. Is this in the
correct place?

> +	return usb_add_phy_dev(phy);
> +}
> +
> +static int phy_remove(struct platform_device *pdev)
> +{
> +	struct tca_apb *ta = platform_get_drvdata(pdev);
> +
> +	usb_remove_phy(&ta->phy);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id intel_usb_phy_dt_ids[] = {
> +	{ .compatible = "intel,lgm-usb-phy" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, intel_usb_phy_dt_ids);
> +
> +static struct platform_driver lgm_phy_driver = {
> +	.driver = {
> +		.name = "lgm-usb-phy",
> +		.of_match_table = intel_usb_phy_dt_ids,
> +	},
> +	.probe = phy_probe,
> +	.remove = phy_remove,
> +};
> +
> +module_platform_driver(lgm_phy_driver);
> +
> +MODULE_DESCRIPTION("Intel LGM USB PHY driver");
> +MODULE_AUTHOR("Li Yin <yin1.li@intel.com>");
> +MODULE_LICENSE("GPL v2");

regards
Philipp