Subject: Re: [PATCH v7 2/3] phy:phy-bcm-ns2-usbdrd:Broadcom USB DRD Phy driver
 for Northstar2
To: Raviteja Garimella <raviteja.garimella@broadcom.com>,
        Rob Herring <robh+dt@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
        Ray Jui <rjui@broadcom.com>, Scott Branden <sbranden@broadcom.com>,
        Jon Mason <jonmason@broadcom.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>
References: <1496408439-30431-1-git-send-email-raviteja.garimella@broadcom.com>
 <1496408439-30431-3-git-send-email-raviteja.garimella@broadcom.com>
CC: <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <bcm-kernel-feedback-list@broadcom.com>,
        <linux-arm-kernel@lists.infradead.org>
From: Kishon Vijay Abraham I <kishon@ti.com>
Message-ID: <98ce8a1c-5c89-ac2a-b2c4-b66c079355b5@ti.com>
Date: Wed, 7 Jun 2017 19:08:41 +0530
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Hi,

On Friday 02 June 2017 06:30 PM, Raviteja Garimella wrote:
> This is driver for USB DRD Phy used in Broadcom's Northstar2
> SoC. The phy can be configured to be in Device mode or Host
> mode based on the type of cable connected to the port. The
> driver registers to  extcon framework to get appropriate
> connect events for Host/Device cables connect/disconnect
> states based on VBUS and ID interrupts.
> 
> Signed-off-by: Raviteja Garimella <raviteja.garimella@broadcom.com>
> ---
>  drivers/phy/Kconfig              |  13 ++
>  drivers/phy/Makefile             |   1 +
>  drivers/phy/phy-bcm-ns2-usbdrd.c | 450 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 464 insertions(+)
>  create mode 100644 drivers/phy/phy-bcm-ns2-usbdrd.c
> 
> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> index afaf7b6..8028da7 100644
> --- a/drivers/phy/Kconfig
> +++ b/drivers/phy/Kconfig
> @@ -507,6 +507,19 @@ config PHY_CYGNUS_PCIE
>  	  Enable this to support the Broadcom Cygnus PCIe PHY.
>  	  If unsure, say N.
>  
> +config PHY_NS2_USB_DRD
> +	tristate "Broadcom Northstar2 USB DRD PHY support"
> +	depends on OF && (ARCH_BCM_IPROC || COMPILE_TEST)
> +	select GENERIC_PHY
> +	select EXTCON
> +	default ARCH_BCM_IPROC
> +	help
> +	  Enable this to support the Broadcom Northstar2 USB DRD PHY.
> +	  This driver initializes the PHY in either HOST or DEVICE mode.
> +	  The host or device configuration is read from device tree.
> +
> +	  If unsure, say N.
> +
>  source "drivers/phy/tegra/Kconfig"
>  
>  config PHY_NS2_PCIE
> diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
> index f8047b4..e5fbb0e 100644
> --- a/drivers/phy/Makefile
> +++ b/drivers/phy/Makefile
> @@ -61,6 +61,7 @@ obj-$(CONFIG_PHY_TUSB1210)		+= phy-tusb1210.o
>  obj-$(CONFIG_PHY_BRCM_SATA)		+= phy-brcm-sata.o
>  obj-$(CONFIG_PHY_PISTACHIO_USB)		+= phy-pistachio-usb.o
>  obj-$(CONFIG_PHY_CYGNUS_PCIE)		+= phy-bcm-cygnus-pcie.o
> +obj-$(CONFIG_PHY_NS2_USB_DRD)		+= phy-bcm-ns2-usbdrd.o
>  obj-$(CONFIG_ARCH_TEGRA) += tegra/
>  obj-$(CONFIG_PHY_NS2_PCIE)		+= phy-bcm-ns2-pcie.o
>  obj-$(CONFIG_PHY_MESON8B_USB2)		+= phy-meson8b-usb2.o
> diff --git a/drivers/phy/phy-bcm-ns2-usbdrd.c b/drivers/phy/phy-bcm-ns2-usbdrd.c
> new file mode 100644
> index 0000000..4a1e181
> --- /dev/null
> +++ b/drivers/phy/phy-bcm-ns2-usbdrd.c
> @@ -0,0 +1,450 @@
> +/*
> + * Copyright (C) 2017 Broadcom
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation version 2.
> + *
> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> + * kind, whether express or implied; without even the implied warranty
> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/extcon.h>
> +#include <linux/gpio.h>
> +#include <linux/gpio/consumer.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/phy/phy.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/workqueue.h>
> +
> +#define ICFG_DRD_AFE		0x0
> +#define ICFG_MISC_STAT		0x18
> +#define ICFG_DRD_P0CTL		0x1C
> +#define ICFG_STRAP_CTRL		0x20
> +#define ICFG_FSM_CTRL		0x24
> +
> +#define ICFG_DEV_BIT		BIT(2)
> +#define IDM_RST_BIT		BIT(0)
> +#define AFE_CORERDY_VDDC	BIT(18)
> +#define PHY_PLL_RESETB		BIT(15)
> +#define PHY_RESETB		BIT(14)
> +#define PHY_PLL_LOCK		BIT(0)
> +
> +#define DRD_DEV_MODE		BIT(20)
> +#define OHCI_OVRCUR_POL		BIT(11)
> +#define ICFG_OFF_MODE		BIT(6)
> +#define PLL_LOCK_RETRY		1000
> +
> +#define EVT_DEVICE		0
> +#define EVT_HOST		1
> +
> +#define DRD_HOST_MODE		(BIT(2) | BIT(3))
> +#define DRD_DEVICE_MODE		(BIT(4) | BIT(5))
> +#define DRD_HOST_VAL		0x803
> +#define DRD_DEV_VAL		0x807
> +#define GPIO_DELAY		20
> +
> +struct ns2_phy_data;
> +struct ns2_phy_driver {
> +	void __iomem *icfgdrd_regs;
> +	void __iomem *idmdrd_rst_ctrl;
> +	void __iomem *crmu_usb2_ctrl;
> +	void __iomem *usb2h_strap_reg;
> +	struct ns2_phy_data *data;
> +	struct extcon_dev *edev;
> +	struct gpio_desc *vbus_gpiod;
> +	struct gpio_desc *id_gpiod;
> +	int id_irq;
> +	int vbus_irq;
> +	unsigned long debounce_jiffies;
> +	struct delayed_work wq_extcon;
> +};
> +
> +struct ns2_phy_data {
> +	struct ns2_phy_driver *driver;
> +	struct phy *phy;
> +	int new_state;
> +};
> +
> +static const unsigned int usb_extcon_cable[] = {
> +	EXTCON_USB,
> +	EXTCON_USB_HOST,
> +	EXTCON_NONE,
> +};
> +
> +static inline int pll_lock_stat(u32 usb_reg, int reg_mask,
> +				struct ns2_phy_driver *driver)
> +{
> +	int retry = PLL_LOCK_RETRY;
> +	u32 val;
> +
> +	do {
> +		udelay(1);
> +		val = readl(driver->icfgdrd_regs + usb_reg);
> +		if (val & reg_mask)
> +			return 0;
> +	} while (--retry > 0);
> +
> +	return -EBUSY;
> +}
> +
> +static int ns2_drd_phy_init(struct phy *phy)
> +{
> +	struct ns2_phy_data *data = phy_get_drvdata(phy);
> +	struct ns2_phy_driver *driver = data->driver;
> +	u32 val;
> +
> +	val = readl(driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +
> +	if (data->new_state == EVT_HOST) {
> +		val &= ~DRD_DEVICE_MODE;
> +		val |= DRD_HOST_MODE;
> +	} else {
> +		val &= ~DRD_HOST_MODE;
> +		val |= DRD_DEVICE_MODE;
> +	}
> +	writel(val, driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +
> +	return 0;
> +}
> +
> +static int ns2_drd_phy_shutdown(struct phy *phy)
> +{
> +	struct ns2_phy_data *data = phy_get_drvdata(phy);
> +	struct ns2_phy_driver *driver = data->driver;
> +	u32 val;
> +
> +	val = readl(driver->crmu_usb2_ctrl);
> +	val &= ~AFE_CORERDY_VDDC;
> +	writel(val, driver->crmu_usb2_ctrl);
> +
> +	val = readl(driver->crmu_usb2_ctrl);
> +	val &= ~DRD_DEV_MODE;
> +	writel(val, driver->crmu_usb2_ctrl);
> +
> +	/* Disable Host and Device Mode */
> +	val = readl(driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +	val &= ~(DRD_HOST_MODE | DRD_DEVICE_MODE | ICFG_OFF_MODE);
> +	writel(val, driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +
> +	return 0;
> +}
> +
> +static int ns2_drd_phy_poweron(struct phy *phy)
> +{
> +	struct ns2_phy_data *data = phy_get_drvdata(phy);
> +	struct ns2_phy_driver *driver = data->driver;
> +	u32 extcon_event = data->new_state;
> +	int ret;
> +	u32 val;
> +
> +	if (extcon_event == EVT_DEVICE) {
> +		writel(DRD_DEV_VAL, driver->icfgdrd_regs + ICFG_DRD_P0CTL);
> +
> +		val = readl(driver->idmdrd_rst_ctrl);
> +		val &= ~IDM_RST_BIT;
> +		writel(val, driver->idmdrd_rst_ctrl);
> +
> +		val = readl(driver->crmu_usb2_ctrl);
> +		val |= (AFE_CORERDY_VDDC | DRD_DEV_MODE);
> +		writel(val, driver->crmu_usb2_ctrl);
> +
> +		/* Bring PHY and PHY_PLL out of Reset */
> +		val = readl(driver->crmu_usb2_ctrl);
> +		val |= (PHY_PLL_RESETB | PHY_RESETB);
> +		writel(val, driver->crmu_usb2_ctrl);
> +
> +		ret = pll_lock_stat(ICFG_MISC_STAT, PHY_PLL_LOCK, driver);
> +		if (ret < 0) {
> +			dev_err(&phy->dev, "Phy PLL lock failed\n");
> +			return ret;
> +		}
> +	} else {
> +		writel(DRD_HOST_VAL, driver->icfgdrd_regs + ICFG_DRD_P0CTL);
> +
> +		val = readl(driver->crmu_usb2_ctrl);
> +		val |= AFE_CORERDY_VDDC;
> +		writel(val, driver->crmu_usb2_ctrl);
> +
> +		ret = pll_lock_stat(ICFG_MISC_STAT, PHY_PLL_LOCK, driver);
> +		if (ret < 0) {
> +			dev_err(&phy->dev, "Phy PLL lock failed\n");
> +			return ret;
> +		}
> +
> +		val = readl(driver->idmdrd_rst_ctrl);
> +		val &= ~IDM_RST_BIT;
> +		writel(val, driver->idmdrd_rst_ctrl);
> +
> +		/* port over current Polarity */
> +		val = readl(driver->usb2h_strap_reg);
> +		val |= OHCI_OVRCUR_POL;
> +		writel(val, driver->usb2h_strap_reg);
> +	}
> +
> +	return 0;
> +}
> +
> +static void connect_change(struct ns2_phy_driver *driver)
> +{
> +	u32 extcon_event;
> +	u32 val;
> +
> +	extcon_event = driver->data->new_state;
> +	val = readl(driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +
> +	switch (extcon_event) {
> +	case EVT_DEVICE:
> +		val &= ~(DRD_HOST_MODE | DRD_DEVICE_MODE);
> +		writel(val, driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +
> +		val = (val & ~DRD_HOST_MODE) | DRD_DEVICE_MODE;
> +		writel(val, driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +
> +		val = readl(driver->icfgdrd_regs + ICFG_DRD_P0CTL);
> +		val |= ICFG_DEV_BIT;
> +		writel(val, driver->icfgdrd_regs + ICFG_DRD_P0CTL);
> +		break;
> +
> +	case EVT_HOST:
> +		val &= ~(DRD_HOST_MODE | DRD_DEVICE_MODE);
> +		writel(val, driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +
> +		val = (val & ~DRD_DEVICE_MODE) | DRD_HOST_MODE;
> +		writel(val, driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +
> +		val = readl(driver->usb2h_strap_reg);
> +		val |= OHCI_OVRCUR_POL;
> +		writel(val, driver->usb2h_strap_reg);
> +
> +		val = readl(driver->icfgdrd_regs + ICFG_DRD_P0CTL);
> +		val &= ~ICFG_DEV_BIT;
> +		writel(val, driver->icfgdrd_regs + ICFG_DRD_P0CTL);
> +		break;
> +
> +	default:
> +		pr_err("Invalid extcon event\n");
> +		break;
> +	}
> +}
> +
> +static void extcon_work(struct work_struct *work)
> +{
> +	struct ns2_phy_driver *driver;
> +	int vbus;
> +	int id;
> +
> +	driver  = container_of(to_delayed_work(work),
> +			       struct ns2_phy_driver, wq_extcon);
> +
> +	id = gpiod_get_value_cansleep(driver->id_gpiod);
> +	vbus = gpiod_get_value_cansleep(driver->vbus_gpiod);
> +
> +	if (!id && vbus) { /* Host connected */
> +		extcon_set_cable_state_(driver->edev, EXTCON_USB_HOST, true);
> +		pr_debug("Host cable connected\n");
> +		driver->data->new_state = EVT_HOST;
> +		connect_change(driver);
> +	} else if (id && !vbus) { /* Disconnected */
> +		extcon_set_cable_state_(driver->edev, EXTCON_USB_HOST, false);
> +		extcon_set_cable_state_(driver->edev, EXTCON_USB, false);
> +		pr_debug("Cable disconnected\n");
> +	} else if (id && vbus) { /* Device connected */
> +		extcon_set_cable_state_(driver->edev, EXTCON_USB, true);
> +		pr_debug("Device cable connected\n");
> +		driver->data->new_state = EVT_DEVICE;
> +		connect_change(driver);
> +	}
> +}
> +
> +static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
> +{
> +	struct ns2_phy_driver *driver = dev_id;
> +
> +	queue_delayed_work(system_power_efficient_wq, &driver->wq_extcon,
> +			   driver->debounce_jiffies);

The gpio_irq_handler is already executing in threaded context. Why do you again
want to schedule a work?
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static struct phy_ops ops = {
> +	.init		= ns2_drd_phy_init,
> +	.power_on	= ns2_drd_phy_poweron,
> +	.power_off	= ns2_drd_phy_shutdown,

rename it to ns2_drd_phy_poweroff?
> +	.owner		= THIS_MODULE,
> +};
> +
> +static const struct of_device_id ns2_drd_phy_dt_ids[] = {
> +	{ .compatible = "brcm,ns2-drd-phy", },
> +	{ }
> +};
> +
> +static int ns2_drd_phy_probe(struct platform_device *pdev)
> +{
> +	struct phy_provider *phy_provider;
> +	struct device *dev = &pdev->dev;
> +	struct ns2_phy_driver *driver;
> +	struct ns2_phy_data *data;
> +	struct resource *res;
> +	int ret;
> +	u32 val;
> +
> +	driver = devm_kzalloc(dev, sizeof(struct ns2_phy_driver),
> +			      GFP_KERNEL);
> +	if (!driver)
> +		return -ENOMEM;
> +
> +	driver->data = devm_kzalloc(dev, sizeof(struct ns2_phy_data),
> +				  GFP_KERNEL);
> +	if (!driver->data)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "icfg");
> +	driver->icfgdrd_regs = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(driver->icfgdrd_regs))
> +		return PTR_ERR(driver->icfgdrd_regs);
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "rst-ctrl");
> +	driver->idmdrd_rst_ctrl = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(driver->idmdrd_rst_ctrl))
> +		return PTR_ERR(driver->idmdrd_rst_ctrl);
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "crmu-ctrl");
> +	driver->crmu_usb2_ctrl = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(driver->crmu_usb2_ctrl))
> +		return PTR_ERR(driver->crmu_usb2_ctrl);
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "usb2-strap");
> +	driver->usb2h_strap_reg = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(driver->usb2h_strap_reg))
> +		return PTR_ERR(driver->usb2h_strap_reg);
> +
> +	 /* create extcon */
> +	driver->id_gpiod = devm_gpiod_get(&pdev->dev, "id", GPIOD_IN);
> +	if (IS_ERR(driver->id_gpiod)) {
> +		dev_err(dev, "failed to get ID GPIO\n");
> +		return PTR_ERR(driver->id_gpiod);
> +	}
> +	driver->vbus_gpiod = devm_gpiod_get(&pdev->dev, "vbus", GPIOD_IN);
> +	if (IS_ERR(driver->vbus_gpiod)) {
> +		dev_err(dev, "failed to get VBUS GPIO\n");
> +		return PTR_ERR(driver->vbus_gpiod);
> +	}
> +
> +	driver->edev = devm_extcon_dev_allocate(dev, usb_extcon_cable);
> +	if (IS_ERR(driver->edev)) {
> +		dev_err(dev, "failed to allocate extcon device\n");
> +		return -ENOMEM;
> +	}
> +
> +	ret = devm_extcon_dev_register(dev, driver->edev);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to register extcon device\n");
> +		goto extcon_free;
> +	}
> +
> +	ret = gpiod_set_debounce(driver->id_gpiod, GPIO_DELAY * 1000);
> +	if (ret < 0)
> +		driver->debounce_jiffies = msecs_to_jiffies(GPIO_DELAY);
> +
> +	INIT_DELAYED_WORK(&driver->wq_extcon, extcon_work);
> +
> +	driver->id_irq = gpiod_to_irq(driver->id_gpiod);
> +	if (driver->id_irq < 0) {
> +		dev_err(dev, "failed to get ID IRQ\n");
> +		ret = driver->id_irq;
> +		goto extcon_unregister;
> +	}
> +	driver->vbus_irq = gpiod_to_irq(driver->vbus_gpiod);
> +	if (driver->vbus_irq < 0) {
> +		dev_err(dev, "failed to get ID IRQ\n");
> +		ret = driver->vbus_irq;
> +		goto extcon_unregister;
> +	}
> +
> +	ret = devm_request_threaded_irq(dev, driver->id_irq, NULL,
> +					gpio_irq_handler,
> +					IRQF_TRIGGER_RISING |
> +					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> +					"usb_id", driver);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to request handler for ID IRQ\n");
> +		goto extcon_unregister;
> +	}
> +	ret = devm_request_threaded_irq(dev, driver->vbus_irq, NULL,
> +					gpio_irq_handler,
> +					IRQF_TRIGGER_RISING |
> +					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> +					"usb_vbus", driver);
> +	if (ret < 0) {
> +		dev_err(dev, "failed to request handler for VBUS IRQ\n");
> +		goto extcon_unregister;
> +	}
> +
> +	dev_set_drvdata(dev, driver);
> +
> +	/* Shutdown all ports. They can be powered up as required */
> +	val = readl(driver->crmu_usb2_ctrl);
> +	val &= ~(AFE_CORERDY_VDDC | PHY_RESETB);
> +	writel(val, driver->crmu_usb2_ctrl);
> +
> +	data = driver->data;
> +	data->phy = devm_phy_create(dev, dev->of_node, &ops);
> +	if (IS_ERR(data->phy)) {
> +		dev_err(dev, "Failed to create usb drd phy\n");
> +		ret = PTR_ERR(data->phy);
> +		goto extcon_unregister;
> +	}
> +
> +	data->driver = driver;
> +	phy_set_drvdata(data->phy, data);
> +
> +	phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
> +	if (IS_ERR(phy_provider)) {
> +		dev_err(dev, "Failed to register as phy provider\n");
> +		ret = PTR_ERR(phy_provider);
> +		goto extcon_unregister;
> +	}
> +
> +	platform_set_drvdata(pdev, driver);
> +
> +	dev_info(dev, "Registered NS2 DRD Phy device\n");
> +	queue_delayed_work(system_power_efficient_wq, &driver->wq_extcon,
> +			   driver->debounce_jiffies);
> +
> +	return 0;
> +
> +extcon_unregister:
> +	devm_extcon_dev_unregister(dev, driver->edev);

devm_* api's should take care of cleaning up itself. Do you really need this?
> +extcon_free:
> +	devm_extcon_dev_free(dev, driver->edev);

here too.

Thanks
Kishon