root/drivers/phy/phy-lgm-usb.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Intel LGM USB PHY driver
 *
 * Copyright (C) 2020 Intel Corporation.
 */

#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/reset.h>
#include <linux/usb/phy.h>
#include <linux/workqueue.h>

#define CTRL1_OFFSET            0x14
#define SRAM_EXT_LD_DONE        BIT(25)
#define SRAM_INIT_DONE          BIT(26)

#define TCPC_OFFSET             0x1014
#define TCPC_MUX_CTL            GENMASK(1, 0)
#define MUX_NC                  0
#define MUX_USB                 1
#define MUX_DP                  2
#define MUX_USBDP               3
#define TCPC_FLIPPED            BIT(2)
#define TCPC_LOW_POWER_EN       BIT(3)
#define TCPC_VALID              BIT(4)
#define TCPC_CONN               \
        (TCPC_VALID | FIELD_PREP(TCPC_MUX_CTL, MUX_USB))
#define TCPC_DISCONN            \
        (TCPC_VALID | FIELD_PREP(TCPC_MUX_CTL, MUX_NC) | TCPC_LOW_POWER_EN)

static const char *const PHY_RESETS[] = { "phy31", "phy", };
static const char *const CTL_RESETS[] = { "apb", "ctrl", };

struct tca_apb {
        struct reset_control *resets[ARRAY_SIZE(PHY_RESETS)];
        struct regulator *vbus;
        struct work_struct wk;
        struct usb_phy phy;

        bool regulator_enabled;
        bool phy_initialized;
        bool connected;
};

static int get_flipped(struct tca_apb *ta, bool *flipped)
{
        union extcon_property_value property;
        int ret;

        ret = extcon_get_property(ta->phy.edev, EXTCON_USB_HOST,
                                  EXTCON_PROP_USB_TYPEC_POLARITY, &property);
        if (ret) {
                dev_err(ta->phy.dev, "no polarity property from extcon\n");
                return ret;
        }

        *flipped = property.intval;

        return 0;
}

static int phy_init(struct usb_phy *phy)
{
        struct tca_apb *ta = container_of(phy, struct tca_apb, phy);
        void __iomem *ctrl1 = phy->io_priv + CTRL1_OFFSET;
        int val, ret, i;

        if (ta->phy_initialized)
                return 0;

        for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++)
                reset_control_deassert(ta->resets[i]);

        ret = readl_poll_timeout(ctrl1, val, val & SRAM_INIT_DONE, 10, 10 * 1000);
        if (ret) {
                dev_err(ta->phy.dev, "SRAM init failed, 0x%x\n", val);
                return ret;
        }

        writel(readl(ctrl1) | SRAM_EXT_LD_DONE, ctrl1);

        ta->phy_initialized = true;
        if (!ta->phy.edev) {
                writel(TCPC_CONN, ta->phy.io_priv + TCPC_OFFSET);
                return phy->set_vbus(phy, true);
        }

        schedule_work(&ta->wk);

        return ret;
}

static void phy_shutdown(struct usb_phy *phy)
{
        struct tca_apb *ta = container_of(phy, struct tca_apb, phy);
        int i;

        if (!ta->phy_initialized)
                return;

        ta->phy_initialized = false;
        flush_work(&ta->wk);
        ta->phy.set_vbus(&ta->phy, false);

        ta->connected = false;
        writel(TCPC_DISCONN, ta->phy.io_priv + TCPC_OFFSET);

        for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++)
                reset_control_assert(ta->resets[i]);
}

static int phy_set_vbus(struct usb_phy *phy, int on)
{
        struct tca_apb *ta = container_of(phy, struct tca_apb, phy);
        int ret;

        if (!!on == ta->regulator_enabled)
                return 0;

        if (on)
                ret = regulator_enable(ta->vbus);
        else
                ret = regulator_disable(ta->vbus);

        if (!ret)
                ta->regulator_enabled = on;

        dev_dbg(ta->phy.dev, "set vbus: %d\n", on);
        return ret;
}

static void tca_work(struct work_struct *work)
{
        struct tca_apb *ta = container_of(work, struct tca_apb, wk);
        bool connected;
        bool flipped = false;
        u32 val;
        int ret;

        ret = get_flipped(ta, &flipped);
        if (ret)
                return;

        connected = extcon_get_state(ta->phy.edev, EXTCON_USB_HOST);
        if (connected == ta->connected)
                return;

        ta->connected = connected;
        if (connected) {
                val = TCPC_CONN;
                if (flipped)
                        val |= TCPC_FLIPPED;
                dev_dbg(ta->phy.dev, "connected%s\n", flipped ? " flipped" : "");
        } else {
                val = TCPC_DISCONN;
                dev_dbg(ta->phy.dev, "disconnected\n");
        }

        writel(val, ta->phy.io_priv + TCPC_OFFSET);

        ret = ta->phy.set_vbus(&ta->phy, connected);
        if (ret)
                dev_err(ta->phy.dev, "failed to set VBUS\n");
}

static int id_notifier(struct notifier_block *nb, unsigned long event, void *ptr)
{
        struct tca_apb *ta = container_of(nb, struct tca_apb, phy.id_nb);

        if (ta->phy_initialized)
                schedule_work(&ta->wk);

        return NOTIFY_DONE;
}

static int vbus_notifier(struct notifier_block *nb, unsigned long evnt, void *ptr)
{
        return NOTIFY_DONE;
}

static int phy_probe(struct platform_device *pdev)
{
        struct reset_control *resets[ARRAY_SIZE(CTL_RESETS)];
        struct device *dev = &pdev->dev;
        struct usb_phy *phy;
        struct tca_apb *ta;
        int i;

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

        platform_set_drvdata(pdev, ta);
        INIT_WORK(&ta->wk, tca_work);

        phy = &ta->phy;
        phy->dev = dev;
        phy->label = dev_name(dev);
        phy->type = USB_PHY_TYPE_USB3;
        phy->init = phy_init;
        phy->shutdown = phy_shutdown;
        phy->set_vbus = phy_set_vbus;
        phy->id_nb.notifier_call = id_notifier;
        phy->vbus_nb.notifier_call = vbus_notifier;

        phy->io_priv = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(phy->io_priv))
                return PTR_ERR(phy->io_priv);

        ta->vbus = devm_regulator_get(dev, "vbus");
        if (IS_ERR(ta->vbus))
                return PTR_ERR(ta->vbus);

        for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++) {
                resets[i] = devm_reset_control_get_exclusive(dev, CTL_RESETS[i]);
                if (IS_ERR(resets[i])) {
                        dev_err(dev, "%s reset not found\n", CTL_RESETS[i]);
                        return PTR_ERR(resets[i]);
                }
        }

        for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++) {
                ta->resets[i] = devm_reset_control_get_exclusive(dev, PHY_RESETS[i]);
                if (IS_ERR(ta->resets[i])) {
                        dev_err(dev, "%s reset not found\n", PHY_RESETS[i]);
                        return PTR_ERR(ta->resets[i]);
                }
        }

        for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++)
                reset_control_assert(resets[i]);

        for (i = 0; i < ARRAY_SIZE(PHY_RESETS); i++)
                reset_control_assert(ta->resets[i]);
        /*
         * Out-of-band reset of the controller after PHY reset will cause
         * controller malfunctioning, so we should use in-band controller
         * reset only and leave the controller de-asserted here.
         */
        for (i = 0; i < ARRAY_SIZE(CTL_RESETS); i++)
                reset_control_deassert(resets[i]);

        /* Need to wait at least 20us after de-assert the controller */
        usleep_range(20, 100);

        return usb_add_phy_dev(phy);
}

static void phy_remove(struct platform_device *pdev)
{
        struct tca_apb *ta = platform_get_drvdata(pdev);

        usb_remove_phy(&ta->phy);
}

static const struct of_device_id intel_usb_phy_dt_ids[] = {
        { .compatible = "intel,lgm-usb-phy" },
        { }
};
MODULE_DEVICE_TABLE(of, intel_usb_phy_dt_ids);

static struct platform_driver lgm_phy_driver = {
        .driver = {
                .name = "lgm-usb-phy",
                .of_match_table = intel_usb_phy_dt_ids,
        },
        .probe = phy_probe,
        .remove = phy_remove,
};

module_platform_driver(lgm_phy_driver);

MODULE_DESCRIPTION("Intel LGM USB PHY driver");
MODULE_AUTHOR("Li Yin <yin1.li@intel.com>");
MODULE_AUTHOR("Vadivel Murugan R <vadivel.muruganx.ramuthevar@linux.intel.com>");
MODULE_LICENSE("GPL v2");