root/drivers/usb/cdns3/cdns3-starfive.c
// SPDX-License-Identifier: GPL-2.0
/*
 * cdns3-starfive.c - StarFive specific Glue layer for Cadence USB Controller
 *
 * Copyright (C) 2023 StarFive Technology Co., Ltd.
 *
 * Author:      Minda Chen <minda.chen@starfivetech.com>
 */

#include <linux/bits.h>
#include <linux/clk.h>
#include <linux/module.h>
#include <linux/mfd/syscon.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/of_platform.h>
#include <linux/reset.h>
#include <linux/regmap.h>
#include <linux/usb/otg.h>
#include "core.h"

#define USB_STRAP_HOST                  BIT(17)
#define USB_STRAP_DEVICE                BIT(18)
#define USB_STRAP_MASK                  GENMASK(18, 16)

#define USB_SUSPENDM_HOST               BIT(19)
#define USB_SUSPENDM_MASK               BIT(19)

#define USB_MISC_CFG_MASK               GENMASK(23, 20)
#define USB_SUSPENDM_BYPS               BIT(20)
#define USB_PLL_EN                      BIT(22)
#define USB_REFCLK_MODE                 BIT(23)

struct cdns_starfive {
        struct device *dev;
        struct regmap *stg_syscon;
        struct reset_control *resets;
        struct clk_bulk_data *clks;
        int num_clks;
        u32 stg_usb_mode;
};

static void cdns_mode_init(struct platform_device *pdev,
                           struct cdns_starfive *data)
{
        enum usb_dr_mode mode;

        regmap_update_bits(data->stg_syscon, data->stg_usb_mode,
                           USB_MISC_CFG_MASK,
                           USB_SUSPENDM_BYPS | USB_PLL_EN | USB_REFCLK_MODE);

        /* dr mode setting */
        mode = usb_get_dr_mode(&pdev->dev);

        switch (mode) {
        case USB_DR_MODE_HOST:
                regmap_update_bits(data->stg_syscon,
                                   data->stg_usb_mode,
                                   USB_STRAP_MASK,
                                   USB_STRAP_HOST);
                regmap_update_bits(data->stg_syscon,
                                   data->stg_usb_mode,
                                   USB_SUSPENDM_MASK,
                                   USB_SUSPENDM_HOST);
                break;

        case USB_DR_MODE_PERIPHERAL:
                regmap_update_bits(data->stg_syscon, data->stg_usb_mode,
                                   USB_STRAP_MASK, USB_STRAP_DEVICE);
                regmap_update_bits(data->stg_syscon, data->stg_usb_mode,
                                   USB_SUSPENDM_MASK, 0);
                break;
        default:
                break;
        }
}

static int cdns_clk_rst_init(struct cdns_starfive *data)
{
        int ret;

        ret = clk_bulk_prepare_enable(data->num_clks, data->clks);
        if (ret)
                return dev_err_probe(data->dev, ret,
                                     "failed to enable clocks\n");

        ret = reset_control_deassert(data->resets);
        if (ret) {
                dev_err(data->dev, "failed to reset clocks\n");
                goto err_clk_init;
        }

        return ret;

err_clk_init:
        clk_bulk_disable_unprepare(data->num_clks, data->clks);
        return ret;
}

static void cdns_clk_rst_deinit(struct cdns_starfive *data)
{
        reset_control_assert(data->resets);
        clk_bulk_disable_unprepare(data->num_clks, data->clks);
}

static int cdns_starfive_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct cdns_starfive *data;
        unsigned int args;
        int ret;

        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->dev = dev;

        data->stg_syscon =
                syscon_regmap_lookup_by_phandle_args(pdev->dev.of_node,
                                                     "starfive,stg-syscon", 1, &args);

        if (IS_ERR(data->stg_syscon))
                return dev_err_probe(dev, PTR_ERR(data->stg_syscon),
                                     "Failed to parse starfive,stg-syscon\n");

        data->stg_usb_mode = args;

        data->num_clks = devm_clk_bulk_get_all(data->dev, &data->clks);
        if (data->num_clks < 0)
                return dev_err_probe(data->dev, -ENODEV,
                                     "Failed to get clocks\n");

        data->resets = devm_reset_control_array_get_exclusive(data->dev);
        if (IS_ERR(data->resets))
                return dev_err_probe(data->dev, PTR_ERR(data->resets),
                                     "Failed to get resets");

        cdns_mode_init(pdev, data);
        ret = cdns_clk_rst_init(data);
        if (ret)
                return ret;

        ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
        if (ret) {
                dev_err(dev, "Failed to create children\n");
                cdns_clk_rst_deinit(data);
                return ret;
        }

        device_set_wakeup_capable(dev, true);
        pm_runtime_set_active(dev);
        pm_runtime_enable(dev);
        platform_set_drvdata(pdev, data);

        return 0;
}

static int cdns_starfive_remove_core(struct device *dev, void *c)
{
        struct platform_device *pdev = to_platform_device(dev);

        platform_device_unregister(pdev);

        return 0;
}

static void cdns_starfive_remove(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct cdns_starfive *data = dev_get_drvdata(dev);

        pm_runtime_get_sync(dev);
        device_for_each_child(dev, NULL, cdns_starfive_remove_core);

        pm_runtime_disable(dev);
        pm_runtime_put_noidle(dev);
        cdns_clk_rst_deinit(data);
        platform_set_drvdata(pdev, NULL);
}

#ifdef CONFIG_PM
static int cdns_starfive_runtime_resume(struct device *dev)
{
        struct cdns_starfive *data = dev_get_drvdata(dev);

        return clk_bulk_prepare_enable(data->num_clks, data->clks);
}

static int cdns_starfive_runtime_suspend(struct device *dev)
{
        struct cdns_starfive *data = dev_get_drvdata(dev);

        clk_bulk_disable_unprepare(data->num_clks, data->clks);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int cdns_starfive_resume(struct device *dev)
{
        struct cdns_starfive *data = dev_get_drvdata(dev);

        return cdns_clk_rst_init(data);
}

static int cdns_starfive_suspend(struct device *dev)
{
        struct cdns_starfive *data = dev_get_drvdata(dev);

        cdns_clk_rst_deinit(data);

        return 0;
}
#endif
#endif

static const struct dev_pm_ops cdns_starfive_pm_ops = {
        SET_RUNTIME_PM_OPS(cdns_starfive_runtime_suspend,
                           cdns_starfive_runtime_resume, NULL)
        SET_SYSTEM_SLEEP_PM_OPS(cdns_starfive_suspend, cdns_starfive_resume)
};

static const struct of_device_id cdns_starfive_of_match[] = {
        { .compatible = "starfive,jh7110-usb", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, cdns_starfive_of_match);

static struct platform_driver cdns_starfive_driver = {
        .probe          = cdns_starfive_probe,
        .remove         = cdns_starfive_remove,
        .driver         = {
                .name   = "cdns3-starfive",
                .of_match_table = cdns_starfive_of_match,
                .pm     = &cdns_starfive_pm_ops,
        },
};
module_platform_driver(cdns_starfive_driver);

MODULE_ALIAS("platform:cdns3-starfive");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Cadence USB3 StarFive Glue Layer");