// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for the TUSB1046-DCI USB Type-C crosspoint switch
 *
 * Copyright (C) 2024 Bootlin
 */

#include <linux/bits.h>
#include <linux/i2c.h>
#include <linux/usb/typec_mux.h>
#include <linux/usb/typec_dp.h>
#include <linux/usb/typec_altmode.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/of_device.h>
#include <linux/device.h>
#include <linux/mutex.h>

#define TUSB1046_REG_GENERAL 0xa

/* General register bits */
#define TUSB1046_GENERAL_FLIPSEL BIT(2)
#define TUSB1046_GENERAL_CTLSEL  GENMASK(1, 0)

/* Mux modes */
#define TUSB1046_CTLSEL_DISABLED          0x0
#define TUSB1046_CTLSEL_USB3              0x1
#define TUSB1046_CTLSEL_4LANE_DP          0x2
#define TUSB1046_CTLSEL_USB3_AND_2LANE_DP 0x3

struct tusb1046_priv {
        struct i2c_client *client;
        struct typec_switch_dev *sw;
        struct typec_mux_dev *mux;

        /* Lock General register during accesses */
        struct mutex general_reg_lock;
};

static int tusb1046_mux_set(struct typec_mux_dev *mux,
                            struct typec_mux_state *state)
{
        struct tusb1046_priv *priv = typec_mux_get_drvdata(mux);
        struct i2c_client *client = priv->client;
        struct device *dev = &client->dev;
        int mode, val, ret = 0;

        if (state->mode >= TYPEC_STATE_MODAL &&
            state->alt->svid != USB_TYPEC_DP_SID)
                return -EINVAL;

        dev_dbg(dev, "mux mode requested: %lu\n", state->mode);

        mutex_lock(&priv->general_reg_lock);

        val = i2c_smbus_read_byte_data(client, TUSB1046_REG_GENERAL);
        if (val < 0) {
                dev_err(dev, "failed to read ctlsel status, err %d\n", val);
                ret = val;
                goto out_unlock;
        }

        switch (state->mode) {
        case TYPEC_STATE_USB:
                mode = TUSB1046_CTLSEL_USB3;
                break;
        case TYPEC_DP_STATE_C:
        case TYPEC_DP_STATE_E:
                mode = TUSB1046_CTLSEL_4LANE_DP;
                break;
        case TYPEC_DP_STATE_D:
                mode = TUSB1046_CTLSEL_USB3_AND_2LANE_DP;
                break;
        case TYPEC_STATE_SAFE:
        default:
                mode = TUSB1046_CTLSEL_DISABLED;
                break;
        }

        val &= ~TUSB1046_GENERAL_CTLSEL;
        val |= mode;

        ret = i2c_smbus_write_byte_data(client, TUSB1046_REG_GENERAL, val);

out_unlock:
        mutex_unlock(&priv->general_reg_lock);
        return ret;
}

static int tusb1046_switch_set(struct typec_switch_dev *sw,
                               enum typec_orientation orientation)
{
        struct tusb1046_priv *priv = typec_switch_get_drvdata(sw);
        struct i2c_client *client = priv->client;
        struct device *dev = &client->dev;
        int val, ret = 0;

        dev_dbg(dev, "setting USB3.0 lane flip for orientation %d\n", orientation);

        mutex_lock(&priv->general_reg_lock);

        val = i2c_smbus_read_byte_data(client, TUSB1046_REG_GENERAL);
        if (val < 0) {
                dev_err(dev, "failed to read flipsel status, err %d\n", val);
                ret = val;
                goto out_unlock;
        }

        if (orientation == TYPEC_ORIENTATION_REVERSE)
                val |= TUSB1046_GENERAL_FLIPSEL;
        else
                val &= ~TUSB1046_GENERAL_FLIPSEL;

        ret = i2c_smbus_write_byte_data(client, TUSB1046_REG_GENERAL, val);

out_unlock:
        mutex_unlock(&priv->general_reg_lock);
        return ret;
}

static int tusb1046_i2c_probe(struct i2c_client *client)
{
        struct typec_switch_desc sw_desc = { };
        struct typec_mux_desc mux_desc = { };
        struct device *dev = &client->dev;
        struct tusb1046_priv *priv;
        int ret = 0;

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

        priv->client = client;

        mutex_init(&priv->general_reg_lock);

        sw_desc.drvdata = priv;
        sw_desc.fwnode = dev_fwnode(dev);
        sw_desc.set = tusb1046_switch_set;

        priv->sw = typec_switch_register(dev, &sw_desc);
        if (IS_ERR(priv->sw)) {
                ret = dev_err_probe(dev, PTR_ERR(priv->sw), "failed to register type-c switch\n");
                goto err_destroy_mutex;
        }

        mux_desc.drvdata = priv;
        mux_desc.fwnode = dev_fwnode(dev);
        mux_desc.set = tusb1046_mux_set;

        priv->mux = typec_mux_register(dev, &mux_desc);
        if (IS_ERR(priv->mux)) {
                ret = dev_err_probe(dev, PTR_ERR(priv->mux), "failed to register type-c mux\n");
                goto err_unregister_switch;
        }

        i2c_set_clientdata(client, priv);

        return 0;

err_unregister_switch:
        typec_switch_unregister(priv->sw);
err_destroy_mutex:
        mutex_destroy(&priv->general_reg_lock);
        return ret;
}

static void tusb1046_i2c_remove(struct i2c_client *client)
{
        struct tusb1046_priv *priv = i2c_get_clientdata(client);

        typec_switch_unregister(priv->sw);
        typec_mux_unregister(priv->mux);
        mutex_destroy(&priv->general_reg_lock);
}

static const struct of_device_id tusb1046_match_table[] = {
        {.compatible = "ti,tusb1046"},
        {},
};

static struct i2c_driver tusb1046_driver = {
        .driver = {
                .name = "tusb1046",
                .of_match_table = tusb1046_match_table,
        },
        .probe = tusb1046_i2c_probe,
        .remove = tusb1046_i2c_remove,
};

module_i2c_driver(tusb1046_driver);

MODULE_DESCRIPTION("TUSB1046 USB Type-C switch driver");
MODULE_AUTHOR("Romain Gantois <romain.gantois@bootlin.com>");
MODULE_LICENSE("GPL");