root/drivers/phy/broadcom/phy-bcm-ns2-usbdrd.c
// SPDX-License-Identifier: GPL-2.0-only
// Copyright (C) 2017 Broadcom

#include <linux/delay.h>
#include <linux/extcon-provider.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/iopoll.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)
{
        u32 val;

        return readl_poll_timeout_atomic(driver->icfgdrd_regs + usb_reg,
                                         val, (val & reg_mask), 1,
                                         PLL_LOCK_RETRY);
}

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_poweroff(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_state_sync(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_state_sync(driver->edev, EXTCON_USB_HOST, false);
                extcon_set_state_sync(driver->edev, EXTCON_USB, false);
                pr_debug("Cable disconnected\n");
        } else if (id && vbus) { /* Device connected */
                extcon_set_state_sync(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);

        return IRQ_HANDLED;
}

static const struct phy_ops ops = {
        .init           = ns2_drd_phy_init,
        .power_on       = ns2_drd_phy_poweron,
        .power_off      = ns2_drd_phy_poweroff,
        .owner          = THIS_MODULE,
};

static const struct of_device_id ns2_drd_phy_dt_ids[] = {
        { .compatible = "brcm,ns2-drd-phy", },
        { }
};
MODULE_DEVICE_TABLE(of, ns2_drd_phy_dt_ids);

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;
        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;

        driver->icfgdrd_regs = devm_platform_ioremap_resource_byname(pdev, "icfg");
        if (IS_ERR(driver->icfgdrd_regs))
                return PTR_ERR(driver->icfgdrd_regs);

        driver->idmdrd_rst_ctrl = devm_platform_ioremap_resource_byname(pdev, "rst-ctrl");
        if (IS_ERR(driver->idmdrd_rst_ctrl))
                return PTR_ERR(driver->idmdrd_rst_ctrl);

        driver->crmu_usb2_ctrl = devm_platform_ioremap_resource_byname(pdev, "crmu-ctrl");
        if (IS_ERR(driver->crmu_usb2_ctrl))
                return PTR_ERR(driver->crmu_usb2_ctrl);

        driver->usb2h_strap_reg = devm_platform_ioremap_resource_byname(pdev, "usb2-strap");
        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");
                return ret;
        }

        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");
                return driver->id_irq;
        }

        driver->vbus_irq = gpiod_to_irq(driver->vbus_gpiod);
        if (driver->vbus_irq < 0) {
                dev_err(dev, "failed to get ID IRQ\n");
                return driver->vbus_irq;
        }

        ret = devm_request_irq(dev, driver->id_irq, gpio_irq_handler,
                               IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
                               "usb_id", driver);
        if (ret < 0) {
                dev_err(dev, "failed to request handler for ID IRQ\n");
                return ret;
        }

        ret = devm_request_irq(dev, driver->vbus_irq, gpio_irq_handler,
                               IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
                               "usb_vbus", driver);
        if (ret < 0) {
                dev_err(dev, "failed to request handler for VBUS IRQ\n");
                return ret;
        }

        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");
                return PTR_ERR(data->phy);
        }

        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");
                return PTR_ERR(phy_provider);
        }

        platform_set_drvdata(pdev, driver);

        queue_delayed_work(system_power_efficient_wq, &driver->wq_extcon,
                           driver->debounce_jiffies);

        return 0;
}

static struct platform_driver ns2_drd_phy_driver = {
        .probe = ns2_drd_phy_probe,
        .driver = {
                .name = "bcm-ns2-usbphy",
                .of_match_table = of_match_ptr(ns2_drd_phy_dt_ids),
        },
};
module_platform_driver(ns2_drd_phy_driver);

MODULE_ALIAS("platform:bcm-ns2-drd-phy");
MODULE_AUTHOR("Broadcom");
MODULE_DESCRIPTION("Broadcom NS2 USB2 PHY driver");
MODULE_LICENSE("GPL v2");