root/drivers/usb/misc/usb3503.c
// SPDX-License-Identifier: GPL-2.0+
/*
 * Driver for SMSC USB3503 USB 2.0 hub controller driver
 *
 * Copyright (c) 2012-2013 Dongjin Kim (tobetter@gmail.com)
 */

#include <linux/clk.h>
#include <linux/i2c.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/platform_data/usb3503.h>
#include <linux/regmap.h>

#define USB3503_VIDL            0x00
#define USB3503_VIDM            0x01
#define USB3503_PIDL            0x02
#define USB3503_PIDM            0x03
#define USB3503_DIDL            0x04
#define USB3503_DIDM            0x05

#define USB3503_CFG1            0x06
#define USB3503_SELF_BUS_PWR    (1 << 7)

#define USB3503_CFG2            0x07
#define USB3503_CFG3            0x08
#define USB3503_NRD             0x09

#define USB3503_PDS             0x0a

#define USB3503_SP_ILOCK        0xe7
#define USB3503_SPILOCK_CONNECT (1 << 1)
#define USB3503_SPILOCK_CONFIG  (1 << 0)

#define USB3503_CFGP            0xee
#define USB3503_CLKSUSP         (1 << 7)

#define USB3503_RESET           0xff

struct usb3503 {
        enum usb3503_mode       mode;
        struct regmap           *regmap;
        struct device           *dev;
        struct clk              *clk;
        u8      port_off_mask;
        struct gpio_desc        *bypass;
        struct gpio_desc        *intn;
        struct gpio_desc        *reset;
        struct gpio_desc        *connect;
        bool    secondary_ref_clk;
};

static int usb3503_connect(struct usb3503 *hub)
{
        struct device *dev = hub->dev;
        int err;

        if (hub->regmap) {
                /* SP_ILOCK: set connect_n, config_n for config */
                err = regmap_write(hub->regmap, USB3503_SP_ILOCK,
                           (USB3503_SPILOCK_CONNECT
                                 | USB3503_SPILOCK_CONFIG));
                if (err < 0) {
                        dev_err(dev, "SP_ILOCK failed (%d)\n", err);
                        return err;
                }

                /* PDS : Set the ports which are disabled in self-powered mode. */
                if (hub->port_off_mask) {
                        err = regmap_update_bits(hub->regmap, USB3503_PDS,
                                        hub->port_off_mask,
                                        hub->port_off_mask);
                        if (err < 0) {
                                dev_err(dev, "PDS failed (%d)\n", err);
                                return err;
                        }
                }

                /* CFG1 : Set SELF_BUS_PWR, this enables self-powered operation. */
                err = regmap_update_bits(hub->regmap, USB3503_CFG1,
                                         USB3503_SELF_BUS_PWR,
                                         USB3503_SELF_BUS_PWR);
                if (err < 0) {
                        dev_err(dev, "CFG1 failed (%d)\n", err);
                        return err;
                }

                /* SP_LOCK: clear connect_n, config_n for hub connect */
                err = regmap_update_bits(hub->regmap, USB3503_SP_ILOCK,
                                         (USB3503_SPILOCK_CONNECT
                                          | USB3503_SPILOCK_CONFIG), 0);
                if (err < 0) {
                        dev_err(dev, "SP_ILOCK failed (%d)\n", err);
                        return err;
                }
        }

        if (hub->connect)
                gpiod_set_value_cansleep(hub->connect, 1);

        hub->mode = USB3503_MODE_HUB;
        dev_info(dev, "switched to HUB mode\n");

        return 0;
}

static int usb3503_switch_mode(struct usb3503 *hub, enum usb3503_mode mode)
{
        struct device *dev = hub->dev;
        int rst, bypass, conn;

        switch (mode) {
        case USB3503_MODE_HUB:
                conn = 1;
                rst = 0;
                bypass = 0;
                break;
        case USB3503_MODE_STANDBY:
                conn = 0;
                rst = 1;
                bypass = 1;
                dev_info(dev, "switched to STANDBY mode\n");
                break;
        case USB3503_MODE_BYPASS:
                conn = 0;
                rst = 0;
                bypass = 1;
                break;
        default:
                dev_err(dev, "unknown mode is requested\n");
                return -EINVAL;
        }

        if (!conn && hub->connect)
                gpiod_set_value_cansleep(hub->connect, 0);

        if (hub->reset)
                gpiod_set_value_cansleep(hub->reset, rst);

        if (hub->bypass)
                gpiod_set_value_cansleep(hub->bypass, bypass);

        if (conn) {
                /* Wait T_HUBINIT == 4ms for hub logic to stabilize */
                usleep_range(4000, 10000);
                return usb3503_connect(hub);
        }

        return 0;
}

static const struct regmap_config usb3503_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,

        .max_register = USB3503_RESET,
};

static int usb3503_probe(struct usb3503 *hub)
{
        struct device *dev = hub->dev;
        struct usb3503_platform_data *pdata = dev_get_platdata(dev);
        struct device_node *np = dev->of_node;
        int err;
        bool is_clk_enabled = false;
        u32 mode = USB3503_MODE_HUB;
        const u32 *property;
        enum gpiod_flags flags;
        int len;

        if (pdata) {
                hub->port_off_mask      = pdata->port_off_mask;
                hub->mode               = pdata->initial_mode;
        } else if (np) {
                u32 rate = 0;
                hub->port_off_mask = 0;

                if (!of_property_read_u32(np, "refclk-frequency", &rate)) {
                        switch (rate) {
                        case 38400000:
                        case 26000000:
                        case 19200000:
                        case 12000000:
                                hub->secondary_ref_clk = 0;
                                break;
                        case 24000000:
                        case 27000000:
                        case 25000000:
                        case 50000000:
                                hub->secondary_ref_clk = 1;
                                break;
                        default:
                                dev_err(dev,
                                        "unsupported reference clock rate (%d)\n",
                                        (int) rate);
                                return -EINVAL;
                        }
                }

                hub->clk = devm_clk_get_optional(dev, "refclk");
                if (IS_ERR(hub->clk)) {
                        dev_err(dev, "unable to request refclk (%ld)\n",
                                        PTR_ERR(hub->clk));
                        return PTR_ERR(hub->clk);
                }

                if (rate != 0) {
                        err = clk_set_rate(hub->clk, rate);
                        if (err) {
                                dev_err(dev,
                                        "unable to set reference clock rate to %d\n",
                                        (int)rate);
                                return err;
                        }
                }

                err = clk_prepare_enable(hub->clk);
                if (err) {
                        dev_err(dev, "unable to enable reference clock\n");
                        return err;
                }

                is_clk_enabled = true;
                property = of_get_property(np, "disabled-ports", &len);
                if (property && (len / sizeof(u32)) > 0) {
                        int i;
                        for (i = 0; i < len / sizeof(u32); i++) {
                                u32 port = be32_to_cpu(property[i]);
                                if ((1 <= port) && (port <= 3))
                                        hub->port_off_mask |= (1 << port);
                        }
                }

                of_property_read_u32(np, "initial-mode", &mode);
                hub->mode = mode;
        }

        if (hub->secondary_ref_clk)
                flags = GPIOD_OUT_LOW;
        else
                flags = GPIOD_OUT_HIGH;
        hub->intn = devm_gpiod_get_optional(dev, "intn", flags);
        if (IS_ERR(hub->intn)) {
                err = PTR_ERR(hub->intn);
                goto err_clk;
        }
        if (hub->intn)
                gpiod_set_consumer_name(hub->intn, "usb3503 intn");

        hub->connect = devm_gpiod_get_optional(dev, "connect", GPIOD_OUT_LOW);
        if (IS_ERR(hub->connect)) {
                err = PTR_ERR(hub->connect);
                goto err_clk;
        }
        if (hub->connect)
                gpiod_set_consumer_name(hub->connect, "usb3503 connect");

        hub->bypass = devm_gpiod_get_optional(dev, "bypass", GPIOD_OUT_HIGH);
        if (IS_ERR(hub->bypass)) {
                err = PTR_ERR(hub->bypass);
                goto err_clk;
        }
        if (hub->bypass)
                gpiod_set_consumer_name(hub->bypass, "usb3503 bypass");

        hub->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
        if (IS_ERR(hub->reset)) {
                err = PTR_ERR(hub->reset);
                goto err_clk;
        }
        if (hub->reset) {
                /* Datasheet defines a hardware reset to be at least 100us */
                usleep_range(100, 10000);
                gpiod_set_consumer_name(hub->reset, "usb3503 reset");
        }

        if (hub->port_off_mask && !hub->regmap)
                dev_err(dev, "Ports disabled with no control interface\n");

        usb3503_switch_mode(hub, hub->mode);

        dev_info(dev, "%s: probed in %s mode\n", __func__,
                        (hub->mode == USB3503_MODE_HUB) ? "hub" : "standby");

        return 0;

err_clk:
        if (is_clk_enabled)
                clk_disable_unprepare(hub->clk);
        return err;
}

static int usb3503_i2c_probe(struct i2c_client *i2c)
{
        struct usb3503 *hub;
        int err;

        hub = devm_kzalloc(&i2c->dev, sizeof(struct usb3503), GFP_KERNEL);
        if (!hub)
                return -ENOMEM;

        i2c_set_clientdata(i2c, hub);
        hub->regmap = devm_regmap_init_i2c(i2c, &usb3503_regmap_config);
        if (IS_ERR(hub->regmap)) {
                err = PTR_ERR(hub->regmap);
                dev_err(&i2c->dev, "Failed to initialise regmap: %d\n", err);
                return err;
        }
        hub->dev = &i2c->dev;

        return usb3503_probe(hub);
}

static void usb3503_i2c_remove(struct i2c_client *i2c)
{
        struct usb3503 *hub;

        hub = i2c_get_clientdata(i2c);
        clk_disable_unprepare(hub->clk);
}

static int usb3503_platform_probe(struct platform_device *pdev)
{
        struct usb3503 *hub;

        hub = devm_kzalloc(&pdev->dev, sizeof(struct usb3503), GFP_KERNEL);
        if (!hub)
                return -ENOMEM;
        hub->dev = &pdev->dev;
        platform_set_drvdata(pdev, hub);

        return usb3503_probe(hub);
}

static void usb3503_platform_remove(struct platform_device *pdev)
{
        struct usb3503 *hub;

        hub = platform_get_drvdata(pdev);
        clk_disable_unprepare(hub->clk);
}

static int __maybe_unused usb3503_suspend(struct usb3503 *hub)
{
        usb3503_switch_mode(hub, USB3503_MODE_STANDBY);
        clk_disable_unprepare(hub->clk);

        return 0;
}

static int __maybe_unused usb3503_resume(struct usb3503 *hub)
{
        clk_prepare_enable(hub->clk);
        usb3503_switch_mode(hub, hub->mode);

        return 0;
}

static int __maybe_unused usb3503_i2c_suspend(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);

        return usb3503_suspend(i2c_get_clientdata(client));
}

static int __maybe_unused usb3503_i2c_resume(struct device *dev)
{
        struct i2c_client *client = to_i2c_client(dev);

        return usb3503_resume(i2c_get_clientdata(client));
}

static int __maybe_unused usb3503_platform_suspend(struct device *dev)
{
        return usb3503_suspend(dev_get_drvdata(dev));
}

static int __maybe_unused usb3503_platform_resume(struct device *dev)
{
        return usb3503_resume(dev_get_drvdata(dev));
}

static SIMPLE_DEV_PM_OPS(usb3503_i2c_pm_ops, usb3503_i2c_suspend,
                usb3503_i2c_resume);

static SIMPLE_DEV_PM_OPS(usb3503_platform_pm_ops, usb3503_platform_suspend,
                usb3503_platform_resume);

static const struct i2c_device_id usb3503_id[] = {
        { USB3503_I2C_NAME },
        { }
};
MODULE_DEVICE_TABLE(i2c, usb3503_id);

#ifdef CONFIG_OF
static const struct of_device_id usb3503_of_match[] = {
        { .compatible = "smsc,usb3503", },
        { .compatible = "smsc,usb3503a", },
        { .compatible = "smsc,usb3803", },
        {},
};
MODULE_DEVICE_TABLE(of, usb3503_of_match);
#endif

static struct i2c_driver usb3503_i2c_driver = {
        .driver = {
                .name = USB3503_I2C_NAME,
                .pm = pm_ptr(&usb3503_i2c_pm_ops),
                .of_match_table = of_match_ptr(usb3503_of_match),
        },
        .probe          = usb3503_i2c_probe,
        .remove         = usb3503_i2c_remove,
        .id_table       = usb3503_id,
};

static struct platform_driver usb3503_platform_driver = {
        .driver = {
                .name = USB3503_I2C_NAME,
                .of_match_table = of_match_ptr(usb3503_of_match),
                .pm = pm_ptr(&usb3503_platform_pm_ops),
        },
        .probe          = usb3503_platform_probe,
        .remove         = usb3503_platform_remove,
};

static int __init usb3503_init(void)
{
        int err;

        err = i2c_add_driver(&usb3503_i2c_driver);
        if (err) {
                pr_err("usb3503: Failed to register I2C driver: %d\n", err);
                return err;
        }

        err = platform_driver_register(&usb3503_platform_driver);
        if (err) {
                pr_err("usb3503: Failed to register platform driver: %d\n",
                       err);
                i2c_del_driver(&usb3503_i2c_driver);
                return err;
        }

        return 0;
}
module_init(usb3503_init);

static void __exit usb3503_exit(void)
{
        platform_driver_unregister(&usb3503_platform_driver);
        i2c_del_driver(&usb3503_i2c_driver);
}
module_exit(usb3503_exit);

MODULE_AUTHOR("Dongjin Kim <tobetter@gmail.com>");
MODULE_DESCRIPTION("USB3503 USB HUB driver");
MODULE_LICENSE("GPL");