root/drivers/misc/hisi_hikey_usb.c
// SPDX-License-Identifier: GPL-2.0
/*
 * Support for usb functionality of Hikey series boards
 * based on Hisilicon Kirin Soc.
 *
 * Copyright (C) 2017-2018 Hilisicon Electronics Co., Ltd.
 *              http://www.huawei.com
 *
 * Authors: Yu Chen <chenyu56@huawei.com>
 */

#include <linux/gpio/consumer.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/platform_device.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/string_choices.h>
#include <linux/usb/role.h>

#define DEVICE_DRIVER_NAME "hisi_hikey_usb"

#define HUB_VBUS_POWER_ON 1
#define HUB_VBUS_POWER_OFF 0
#define USB_SWITCH_TO_HUB 1
#define USB_SWITCH_TO_TYPEC 0
#define TYPEC_VBUS_POWER_ON 1
#define TYPEC_VBUS_POWER_OFF 0

struct hisi_hikey_usb {
        struct device *dev;
        struct gpio_desc *otg_switch;
        struct gpio_desc *typec_vbus;
        struct gpio_desc *reset;

        struct regulator *regulator;

        struct usb_role_switch *hub_role_sw;

        struct usb_role_switch *dev_role_sw;
        enum usb_role role;

        struct mutex lock;
        struct work_struct work;

        struct notifier_block nb;
};

static void hub_power_ctrl(struct hisi_hikey_usb *hisi_hikey_usb, int value)
{
        int ret, status;

        if (!hisi_hikey_usb->regulator)
                return;

        status = regulator_is_enabled(hisi_hikey_usb->regulator);
        if (status == !!value)
                return;

        if (value)
                ret = regulator_enable(hisi_hikey_usb->regulator);
        else
                ret = regulator_disable(hisi_hikey_usb->regulator);

        if (ret)
                dev_err(hisi_hikey_usb->dev,
                        "Can't switch regulator state to %s\n",
                        str_enabled_disabled(value));
}

static void usb_switch_ctrl(struct hisi_hikey_usb *hisi_hikey_usb,
                            int switch_to)
{
        if (!hisi_hikey_usb->otg_switch)
                return;

        gpiod_set_value_cansleep(hisi_hikey_usb->otg_switch, switch_to);
}

static void usb_typec_power_ctrl(struct hisi_hikey_usb *hisi_hikey_usb,
                                 int value)
{
        if (!hisi_hikey_usb->typec_vbus)
                return;

        gpiod_set_value_cansleep(hisi_hikey_usb->typec_vbus, value);
}

static void relay_set_role_switch(struct work_struct *work)
{
        struct hisi_hikey_usb *hisi_hikey_usb = container_of(work,
                                                        struct hisi_hikey_usb,
                                                        work);
        struct usb_role_switch *sw;
        enum usb_role role;

        if (!hisi_hikey_usb || !hisi_hikey_usb->dev_role_sw)
                return;

        mutex_lock(&hisi_hikey_usb->lock);
        switch (hisi_hikey_usb->role) {
        case USB_ROLE_NONE:
                usb_typec_power_ctrl(hisi_hikey_usb, TYPEC_VBUS_POWER_OFF);
                usb_switch_ctrl(hisi_hikey_usb, USB_SWITCH_TO_HUB);
                hub_power_ctrl(hisi_hikey_usb, HUB_VBUS_POWER_ON);
                break;
        case USB_ROLE_HOST:
                hub_power_ctrl(hisi_hikey_usb, HUB_VBUS_POWER_OFF);
                usb_switch_ctrl(hisi_hikey_usb, USB_SWITCH_TO_TYPEC);
                usb_typec_power_ctrl(hisi_hikey_usb, TYPEC_VBUS_POWER_ON);
                break;
        case USB_ROLE_DEVICE:
                hub_power_ctrl(hisi_hikey_usb, HUB_VBUS_POWER_OFF);
                usb_typec_power_ctrl(hisi_hikey_usb, TYPEC_VBUS_POWER_OFF);
                usb_switch_ctrl(hisi_hikey_usb, USB_SWITCH_TO_TYPEC);
                break;
        default:
                break;
        }
        sw = hisi_hikey_usb->dev_role_sw;
        role = hisi_hikey_usb->role;
        mutex_unlock(&hisi_hikey_usb->lock);

        usb_role_switch_set_role(sw, role);
}

static int hub_usb_role_switch_set(struct usb_role_switch *sw, enum usb_role role)
{
        struct hisi_hikey_usb *hisi_hikey_usb = usb_role_switch_get_drvdata(sw);

        if (!hisi_hikey_usb || !hisi_hikey_usb->dev_role_sw)
                return -EINVAL;

        mutex_lock(&hisi_hikey_usb->lock);
        hisi_hikey_usb->role = role;
        mutex_unlock(&hisi_hikey_usb->lock);

        schedule_work(&hisi_hikey_usb->work);

        return 0;
}

static int hisi_hikey_usb_of_role_switch(struct platform_device *pdev,
                                         struct hisi_hikey_usb *hisi_hikey_usb)
{
        struct device *dev = &pdev->dev;
        struct usb_role_switch_desc hub_role_switch = {NULL};

        if (!device_property_read_bool(dev, "usb-role-switch"))
                return 0;

        hisi_hikey_usb->otg_switch = devm_gpiod_get(dev, "otg-switch",
                                                    GPIOD_OUT_HIGH);
        if (IS_ERR(hisi_hikey_usb->otg_switch)) {
                dev_err(dev, "get otg-switch failed with error %ld\n",
                        PTR_ERR(hisi_hikey_usb->otg_switch));
                return PTR_ERR(hisi_hikey_usb->otg_switch);
        }

        hisi_hikey_usb->typec_vbus = devm_gpiod_get(dev, "typec-vbus",
                                                    GPIOD_OUT_LOW);
        if (IS_ERR(hisi_hikey_usb->typec_vbus)) {
                dev_err(dev, "get typec-vbus failed with error %ld\n",
                        PTR_ERR(hisi_hikey_usb->typec_vbus));
                return PTR_ERR(hisi_hikey_usb->typec_vbus);
        }

        hisi_hikey_usb->reset = devm_gpiod_get_optional(dev,
                                                        "hub-reset-en",
                                                        GPIOD_OUT_HIGH);
        if (IS_ERR(hisi_hikey_usb->reset)) {
                dev_err(dev, "get hub-reset-en failed with error %ld\n",
                        PTR_ERR(hisi_hikey_usb->reset));
                return PTR_ERR(hisi_hikey_usb->reset);
        }

        hisi_hikey_usb->dev_role_sw = usb_role_switch_get(dev);
        if (!hisi_hikey_usb->dev_role_sw)
                return -EPROBE_DEFER;
        if (IS_ERR(hisi_hikey_usb->dev_role_sw)) {
                dev_err(dev, "get device role switch failed with error %ld\n",
                        PTR_ERR(hisi_hikey_usb->dev_role_sw));
                return PTR_ERR(hisi_hikey_usb->dev_role_sw);
        }

        INIT_WORK(&hisi_hikey_usb->work, relay_set_role_switch);

        hub_role_switch.fwnode = dev_fwnode(dev);
        hub_role_switch.set = hub_usb_role_switch_set;
        hub_role_switch.driver_data = hisi_hikey_usb;

        hisi_hikey_usb->hub_role_sw = usb_role_switch_register(dev,
                                                               &hub_role_switch);

        if (IS_ERR(hisi_hikey_usb->hub_role_sw)) {
                dev_err(dev,
                        "failed to register hub role with error %ld\n",
                        PTR_ERR(hisi_hikey_usb->hub_role_sw));
                usb_role_switch_put(hisi_hikey_usb->dev_role_sw);
                return PTR_ERR(hisi_hikey_usb->hub_role_sw);
        }

        return 0;
}

static int hisi_hikey_usb_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct hisi_hikey_usb *hisi_hikey_usb;
        int ret;

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

        hisi_hikey_usb->dev = &pdev->dev;
        mutex_init(&hisi_hikey_usb->lock);

        hisi_hikey_usb->regulator = devm_regulator_get(dev, "hub-vdd");
        if (IS_ERR(hisi_hikey_usb->regulator)) {
                if (PTR_ERR(hisi_hikey_usb->regulator) == -EPROBE_DEFER) {
                        dev_info(dev, "waiting for hub-vdd-supply\n");
                        return PTR_ERR(hisi_hikey_usb->regulator);
                }
                dev_err(dev, "get hub-vdd-supply failed with error %ld\n",
                        PTR_ERR(hisi_hikey_usb->regulator));
                return PTR_ERR(hisi_hikey_usb->regulator);
        }

        ret = hisi_hikey_usb_of_role_switch(pdev, hisi_hikey_usb);
        if (ret)
                return ret;

        platform_set_drvdata(pdev, hisi_hikey_usb);

        return 0;
}

static void hisi_hikey_usb_remove(struct platform_device *pdev)
{
        struct hisi_hikey_usb *hisi_hikey_usb = platform_get_drvdata(pdev);

        if (hisi_hikey_usb->hub_role_sw) {
                usb_role_switch_unregister(hisi_hikey_usb->hub_role_sw);

                if (hisi_hikey_usb->dev_role_sw)
                        usb_role_switch_put(hisi_hikey_usb->dev_role_sw);
        } else {
                hub_power_ctrl(hisi_hikey_usb, HUB_VBUS_POWER_OFF);
        }
}

static const struct of_device_id id_table_hisi_hikey_usb[] = {
        { .compatible = "hisilicon,usbhub" },
        {}
};
MODULE_DEVICE_TABLE(of, id_table_hisi_hikey_usb);

static struct platform_driver hisi_hikey_usb_driver = {
        .probe = hisi_hikey_usb_probe,
        .remove = hisi_hikey_usb_remove,
        .driver = {
                .name = DEVICE_DRIVER_NAME,
                .of_match_table = id_table_hisi_hikey_usb,
        },
};

module_platform_driver(hisi_hikey_usb_driver);

MODULE_AUTHOR("Yu Chen <chenyu56@huawei.com>");
MODULE_DESCRIPTION("Driver Support for USB functionality of Hikey");
MODULE_LICENSE("GPL v2");