Message-ID: <588A190D.3000606@ti.com>
Date:   Thu, 26 Jan 2017 21:13:09 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Raviteja Garimella <raviteja.garimella@...adcom.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Ray Jui <rjui@...adcom.com>,
        Scott Branden <sbranden@...adcom.com>,
        Jon Mason <jonmason@...adcom.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>
CC:     <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <bcm-kernel-feedback-list@...adcom.com>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2 2/3] Broadcom USB DRD Phy driver for Northstar2

Hi,

On Wednesday 18 January 2017 05:50 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@...adcom.com>
> ---
>  drivers/phy/Kconfig              |  13 +
>  drivers/phy/Makefile             |   1 +
>  drivers/phy/phy-bcm-ns2-usbdrd.c | 588 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 602 insertions(+)
>  create mode 100644 drivers/phy/phy-bcm-ns2-usbdrd.c
> 
> diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
> index e8eb7f2..1b3de42 100644
> --- a/drivers/phy/Kconfig
> +++ b/drivers/phy/Kconfig
> @@ -463,6 +463,19 @@ 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 65eb2f4..cfbdd9a 100644
> --- a/drivers/phy/Makefile
> +++ b/drivers/phy/Makefile
> @@ -56,6 +56,7 @@ 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..e9478d1
> --- /dev/null
> +++ b/drivers/phy/phy-bcm-ns2-usbdrd.c
> @@ -0,0 +1,588 @@
> +/*
> + * Copyright (C) 2016 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 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 EVT_IDLE		2
> +
> +#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
> +#define PHY_WQ_DELAY		msecs_to_jiffies(600)
> +
> +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;
> +	spinlock_t lock; /* spin lock for phy driver */
> +	bool host_mode;
> +	struct ns2_phy_data *data;
> +	struct extcon_specific_cable_nb extcon_dev;
> +	struct extcon_specific_cable_nb extcon_host;
> +	struct notifier_block host_nb;
> +	struct notifier_block dev_nb;
> +	struct delayed_work conn_work;
> +	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;
> +	bool poweron;
> +};
> +
> +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;
> +	unsigned long flags;
> +	u32 val;
> +
> +	spin_lock_irqsave(&driver->lock, flags);

Is this a multi-phy phy driver? if not remove the spinlock used in this driver.
> +
> +	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);
> +
> +	spin_unlock_irqrestore(&driver->lock, flags);
> +	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;
> +	unsigned long flags;
> +	u32 val;
> +
> +	spin_lock_irqsave(&driver->lock, flags);
> +	if (!data->poweron)
> +		goto exit;
> +
> +	val = readl(driver->crmu_usb2_ctrl);
> +	val &= ~AFE_CORERDY_VDDC;
> +	writel(val, driver->crmu_usb2_ctrl);
> +
> +	driver->host_mode = 0;
> +	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);
> +
> +	data->poweron = 0;
> +exit:
> +	spin_unlock_irqrestore(&driver->lock, flags);
> +	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;
> +	unsigned long flags;
> +	int ret;
> +	u32 val;
> +
> +	spin_lock_irqsave(&driver->lock, flags);
> +	if (extcon_event == EVT_DEVICE) {
> +		if (data->poweron)
> +			goto exit;
> +
> +		writel(DRD_DEV_VAL, driver->icfgdrd_regs + ICFG_DRD_P0CTL);
> +
> +		val = readl(driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +		val &= ~(DRD_HOST_MODE | ICFG_OFF_MODE);
> +		val |= DRD_DEVICE_MODE;
> +		writel(val, driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +
> +		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");
> +			goto err_shutdown;
> +		}
> +	} else {
> +		if (data->poweron && driver->host_mode)
> +			goto exit;
> +
> +		writel(DRD_HOST_VAL, driver->icfgdrd_regs + ICFG_DRD_P0CTL);
> +
> +		val = readl(driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +		val &= ~(DRD_DEVICE_MODE | ICFG_OFF_MODE);
> +		val |= DRD_HOST_MODE;
> +		writel(val, driver->icfgdrd_regs + ICFG_FSM_CTRL);
> +
> +		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");
> +			goto err_shutdown;
> +		}
> +
> +		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);
> +
> +		driver->host_mode = 1;
> +	}
> +
> +	data->poweron = 1;

phy-core performs the reference counting. This should be not needed here.
> +exit:
> +	spin_unlock_irqrestore(&driver->lock, flags);
> +	return 0;
> +
> +err_shutdown:
> +	data->poweron = 1;
> +	spin_unlock_irqrestore(&driver->lock, flags);
> +	ns2_drd_phy_shutdown(phy);
> +	return ret;
> +}
> +
> +static void connect_work(struct work_struct *work)
> +{
> +	struct ns2_phy_driver *driver;
> +	struct ns2_phy_data *data;
> +	u32 extcon_event;
> +
> +	driver  = container_of(to_delayed_work(work),
> +			       struct ns2_phy_driver, conn_work);
> +	data = driver->data;
> +	extcon_event = data->new_state;
> +
> +	if (extcon_event == EVT_DEVICE || extcon_event == EVT_HOST) {
> +		ns2_drd_phy_init(data->phy);
> +		ns2_drd_phy_poweron(data->phy);

Ah, there are two ways in which you can phy_init/poweron can be done. That's
why you used spinlock.

If it's based on what cable is connected, why do you even need phy ops? I think
the phy ops should be split so that the init/poweron should be done in phy ops
and host/device mode specific config should be done in extcon event.

Thanks
Kishon

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