root/drivers/usb/host/ehci-exynos.c
// SPDX-License-Identifier: GPL-2.0+
/*
 * Samsung Exynos USB HOST EHCI Controller
 *
 * Copyright (C) 2011 Samsung Electronics Co.Ltd
 * Author: Jingoo Han <jg1.han@samsung.com>
 * Author: Joonyoung Shim <jy0922.shim@samsung.com>
 */

#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/gpio/consumer.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>

#include "ehci.h"

#define DRIVER_DESC "EHCI Exynos driver"

#define EHCI_INSNREG00(base)                    (base + 0x90)
#define EHCI_INSNREG00_ENA_INCR16               (0x1 << 25)
#define EHCI_INSNREG00_ENA_INCR8                (0x1 << 24)
#define EHCI_INSNREG00_ENA_INCR4                (0x1 << 23)
#define EHCI_INSNREG00_ENA_INCRX_ALIGN          (0x1 << 22)
#define EHCI_INSNREG00_ENABLE_DMA_BURST \
        (EHCI_INSNREG00_ENA_INCR16 | EHCI_INSNREG00_ENA_INCR8 | \
         EHCI_INSNREG00_ENA_INCR4 | EHCI_INSNREG00_ENA_INCRX_ALIGN)

static struct hc_driver __read_mostly exynos_ehci_hc_driver;

#define PHY_NUMBER 3

struct exynos_ehci_hcd {
        struct clk *clk;
        struct device_node *of_node;
        struct phy *phy[PHY_NUMBER];
        bool legacy_phy;
};

#define to_exynos_ehci(hcd) (struct exynos_ehci_hcd *)(hcd_to_ehci(hcd)->priv)

static int exynos_ehci_get_phy(struct device *dev,
                                struct exynos_ehci_hcd *exynos_ehci)
{
        struct phy *phy;
        int phy_number, num_phys;
        int ret;

        /* Get PHYs for the controller */
        num_phys = of_count_phandle_with_args(dev->of_node, "phys",
                                              "#phy-cells");
        for (phy_number = 0; phy_number < num_phys; phy_number++) {
                phy = devm_of_phy_get_by_index(dev, dev->of_node, phy_number);
                if (IS_ERR(phy))
                        return PTR_ERR(phy);
                exynos_ehci->phy[phy_number] = phy;
        }
        if (num_phys > 0)
                return 0;

        /* Get PHYs using legacy bindings */
        for_each_available_child_of_node_scoped(dev->of_node, child) {
                ret = of_property_read_u32(child, "reg", &phy_number);
                if (ret) {
                        dev_err(dev, "Failed to parse device tree\n");
                        return ret;
                }

                if (phy_number >= PHY_NUMBER) {
                        dev_err(dev, "Invalid number of PHYs\n");
                        return -EINVAL;
                }

                phy = devm_of_phy_optional_get(dev, child, NULL);
                exynos_ehci->phy[phy_number] = phy;
                if (IS_ERR(phy))
                        return PTR_ERR(phy);
        }

        exynos_ehci->legacy_phy = true;
        return 0;
}

static int exynos_ehci_phy_enable(struct device *dev)
{
        struct usb_hcd *hcd = dev_get_drvdata(dev);
        struct exynos_ehci_hcd *exynos_ehci = to_exynos_ehci(hcd);
        int i;
        int ret = 0;

        for (i = 0; ret == 0 && i < PHY_NUMBER; i++)
                ret = phy_power_on(exynos_ehci->phy[i]);
        if (ret)
                for (i--; i >= 0; i--)
                        phy_power_off(exynos_ehci->phy[i]);

        return ret;
}

static void exynos_ehci_phy_disable(struct device *dev)
{
        struct usb_hcd *hcd = dev_get_drvdata(dev);
        struct exynos_ehci_hcd *exynos_ehci = to_exynos_ehci(hcd);
        int i;

        for (i = 0; i < PHY_NUMBER; i++)
                phy_power_off(exynos_ehci->phy[i]);
}

static void exynos_setup_vbus_gpio(struct device *dev)
{
        struct gpio_desc *gpio;
        int err;

        gpio = devm_gpiod_get_optional(dev, "samsung,vbus", GPIOD_OUT_HIGH);
        err = PTR_ERR_OR_ZERO(gpio);
        if (err)
                dev_err(dev, "can't request ehci vbus gpio: %d\n", err);
}

static int exynos_ehci_probe(struct platform_device *pdev)
{
        struct exynos_ehci_hcd *exynos_ehci;
        struct usb_hcd *hcd;
        struct ehci_hcd *ehci;
        struct resource *res;
        int irq;
        int err;

        /*
         * Right now device-tree probed devices don't get dma_mask set.
         * Since shared usb code relies on it, set it here for now.
         * Once we move to full device tree support this will vanish off.
         */
        err = dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
        if (err)
                return err;

        exynos_setup_vbus_gpio(&pdev->dev);

        hcd = usb_create_hcd(&exynos_ehci_hc_driver,
                             &pdev->dev, dev_name(&pdev->dev));
        if (!hcd) {
                dev_err(&pdev->dev, "Unable to create HCD\n");
                return -ENOMEM;
        }
        exynos_ehci = to_exynos_ehci(hcd);

        err = exynos_ehci_get_phy(&pdev->dev, exynos_ehci);
        if (err)
                goto fail_io;

        exynos_ehci->clk = devm_clk_get_enabled(&pdev->dev, "usbhost");

        if (IS_ERR(exynos_ehci->clk)) {
                dev_err(&pdev->dev, "Failed to get usbhost clock\n");
                err = PTR_ERR(exynos_ehci->clk);
                goto fail_io;
        }

        hcd->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
        if (IS_ERR(hcd->regs)) {
                err = PTR_ERR(hcd->regs);
                goto fail_io;
        }

        hcd->rsrc_start = res->start;
        hcd->rsrc_len = resource_size(res);

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                err = irq;
                goto fail_io;
        }

        err = exynos_ehci_phy_enable(&pdev->dev);
        if (err) {
                dev_err(&pdev->dev, "Failed to enable USB phy\n");
                goto fail_io;
        }

        ehci = hcd_to_ehci(hcd);
        ehci->caps = hcd->regs;

        /*
         * Workaround: reset of_node pointer to avoid conflict between legacy
         * Exynos EHCI port subnodes and generic USB device bindings
         */
        exynos_ehci->of_node = pdev->dev.of_node;
        if (exynos_ehci->legacy_phy)
                pdev->dev.of_node = NULL;

        /* DMA burst Enable */
        writel(EHCI_INSNREG00_ENABLE_DMA_BURST, EHCI_INSNREG00(hcd->regs));

        err = usb_add_hcd(hcd, irq, IRQF_SHARED);
        if (err) {
                dev_err(&pdev->dev, "Failed to add USB HCD\n");
                goto fail_add_hcd;
        }
        device_wakeup_enable(hcd->self.controller);

        platform_set_drvdata(pdev, hcd);

        return 0;

fail_add_hcd:
        exynos_ehci_phy_disable(&pdev->dev);
        pdev->dev.of_node = exynos_ehci->of_node;
fail_io:
        usb_put_hcd(hcd);
        return err;
}

static void exynos_ehci_remove(struct platform_device *pdev)
{
        struct usb_hcd *hcd = platform_get_drvdata(pdev);
        struct exynos_ehci_hcd *exynos_ehci = to_exynos_ehci(hcd);

        pdev->dev.of_node = exynos_ehci->of_node;

        usb_remove_hcd(hcd);

        exynos_ehci_phy_disable(&pdev->dev);

        usb_put_hcd(hcd);
}

static int exynos_ehci_suspend(struct device *dev)
{
        struct usb_hcd *hcd = dev_get_drvdata(dev);
        struct exynos_ehci_hcd *exynos_ehci = to_exynos_ehci(hcd);

        bool do_wakeup = device_may_wakeup(dev);
        int rc;

        rc = ehci_suspend(hcd, do_wakeup);
        if (rc)
                return rc;

        exynos_ehci_phy_disable(dev);

        clk_disable_unprepare(exynos_ehci->clk);

        return rc;
}

static int exynos_ehci_resume(struct device *dev)
{
        struct usb_hcd *hcd = dev_get_drvdata(dev);
        struct exynos_ehci_hcd *exynos_ehci = to_exynos_ehci(hcd);
        int ret;

        ret = clk_prepare_enable(exynos_ehci->clk);
        if (ret)
                return ret;

        ret = exynos_ehci_phy_enable(dev);
        if (ret) {
                dev_err(dev, "Failed to enable USB phy\n");
                clk_disable_unprepare(exynos_ehci->clk);
                return ret;
        }

        /* DMA burst Enable */
        writel(EHCI_INSNREG00_ENABLE_DMA_BURST, EHCI_INSNREG00(hcd->regs));

        ehci_resume(hcd, false);
        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(exynos_ehci_pm_ops,
                                exynos_ehci_suspend, exynos_ehci_resume);

#ifdef CONFIG_OF
static const struct of_device_id exynos_ehci_match[] = {
        { .compatible = "samsung,exynos4210-ehci" },
        {},
};
MODULE_DEVICE_TABLE(of, exynos_ehci_match);
#endif

static struct platform_driver exynos_ehci_driver = {
        .probe          = exynos_ehci_probe,
        .remove         = exynos_ehci_remove,
        .shutdown       = usb_hcd_platform_shutdown,
        .driver = {
                .name   = "exynos-ehci",
                .pm     = pm_ptr(&exynos_ehci_pm_ops),
                .of_match_table = of_match_ptr(exynos_ehci_match),
        }
};
static const struct ehci_driver_overrides exynos_overrides __initconst = {
        .extra_priv_size = sizeof(struct exynos_ehci_hcd),
};

static int __init ehci_exynos_init(void)
{
        if (usb_disabled())
                return -ENODEV;

        ehci_init_driver(&exynos_ehci_hc_driver, &exynos_overrides);
        return platform_driver_register(&exynos_ehci_driver);
}
module_init(ehci_exynos_init);

static void __exit ehci_exynos_cleanup(void)
{
        platform_driver_unregister(&exynos_ehci_driver);
}
module_exit(ehci_exynos_cleanup);

MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_ALIAS("platform:exynos-ehci");
MODULE_AUTHOR("Jingoo Han");
MODULE_AUTHOR("Joonyoung Shim");
MODULE_LICENSE("GPL v2");