// SPDX-License-Identifier: GPL-2.0-only
/*
 * Broadcom Northstar USB 2.0 PHY Driver
 *
 * Copyright (C) 2016 Rafał Miłecki <zajec5@gmail.com>
 */

#include <linux/bcma/bcma.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/slab.h>

struct bcm_ns_usb2 {
        struct device *dev;
        struct clk *ref_clk;
        struct phy *phy;
        struct regmap *clkset;
        void __iomem *base;
};

static int bcm_ns_usb2_phy_init(struct phy *phy)
{
        struct bcm_ns_usb2 *usb2 = phy_get_drvdata(phy);
        struct device *dev = usb2->dev;
        u32 ref_clk_rate, usb2ctl, usb_pll_ndiv, usb_pll_pdiv;
        int err = 0;

        err = clk_prepare_enable(usb2->ref_clk);
        if (err < 0) {
                dev_err(dev, "Failed to prepare ref clock: %d\n", err);
                goto err_out;
        }

        ref_clk_rate = clk_get_rate(usb2->ref_clk);
        if (!ref_clk_rate) {
                dev_err(dev, "Failed to get ref clock rate\n");
                err = -EINVAL;
                goto err_clk_off;
        }

        usb2ctl = readl(usb2->base);

        if (usb2ctl & BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK) {
                usb_pll_pdiv = usb2ctl;
                usb_pll_pdiv &= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_MASK;
                usb_pll_pdiv >>= BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_PDIV_SHIFT;
        } else {
                usb_pll_pdiv = 1 << 3;
        }

        /* Calculate ndiv based on a solid 1920 MHz that is for USB2 PHY */
        usb_pll_ndiv = (1920000000 * usb_pll_pdiv) / ref_clk_rate;

        /* Unlock DMU PLL settings with some magic value */
        regmap_write(usb2->clkset, 0, 0x0000ea68);

        /* Write USB 2.0 PLL control setting */
        usb2ctl &= ~BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_MASK;
        usb2ctl |= usb_pll_ndiv << BCMA_DMU_CRU_USB2_CONTROL_USB_PLL_NDIV_SHIFT;

        writel(usb2ctl, usb2->base);

        /* Lock DMU PLL settings */
        regmap_write(usb2->clkset, 0, 0x00000000);

err_clk_off:
        clk_disable_unprepare(usb2->ref_clk);
err_out:
        return err;
}

static const struct phy_ops ops = {
        .init           = bcm_ns_usb2_phy_init,
        .owner          = THIS_MODULE,
};

static int bcm_ns_usb2_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct bcm_ns_usb2 *usb2;
        struct phy_provider *phy_provider;

        usb2 = devm_kzalloc(&pdev->dev, sizeof(*usb2), GFP_KERNEL);
        if (!usb2)
                return -ENOMEM;
        usb2->dev = dev;

        usb2->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(usb2->base)) {
                dev_err(dev, "Failed to map control reg\n");
                return PTR_ERR(usb2->base);
        }

        usb2->clkset = syscon_regmap_lookup_by_phandle(dev->of_node,
                                                       "brcm,syscon-clkset");
        if (IS_ERR(usb2->clkset)) {
                dev_err(dev, "Failed to lookup clkset regmap\n");
                return PTR_ERR(usb2->clkset);
        }

        usb2->ref_clk = devm_clk_get(dev, "phy-ref-clk");
        if (IS_ERR(usb2->ref_clk)) {
                dev_err_probe(dev, PTR_ERR(usb2->ref_clk), "failed to get ref clk\n");
                return PTR_ERR(usb2->ref_clk);
        }

        usb2->phy = devm_phy_create(dev, NULL, &ops);
        if (IS_ERR(usb2->phy))
                return PTR_ERR(usb2->phy);

        phy_set_drvdata(usb2->phy, usb2);
        platform_set_drvdata(pdev, usb2);

        phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
        return PTR_ERR_OR_ZERO(phy_provider);
}

static const struct of_device_id bcm_ns_usb2_id_table[] = {
        { .compatible = "brcm,ns-usb2-phy", },
        {},
};
MODULE_DEVICE_TABLE(of, bcm_ns_usb2_id_table);

static struct platform_driver bcm_ns_usb2_driver = {
        .probe          = bcm_ns_usb2_probe,
        .driver = {
                .name = "bcm_ns_usb2",
                .of_match_table = bcm_ns_usb2_id_table,
        },
};
module_platform_driver(bcm_ns_usb2_driver);

MODULE_DESCRIPTION("Broadcom Northstar USB 2.0 PHY Driver");
MODULE_LICENSE("GPL v2");