root/drivers/usb/typec/mux/it5205.c
// SPDX-License-Identifier: GPL-2.0
/*
 * ITE IT5205 Type-C USB alternate mode passive mux
 *
 * Copyright (c) 2020 MediaTek Inc.
 * Copyright (c) 2024 Collabora Ltd.
 *                    AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
 *
 */

#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/usb/tcpm.h>
#include <linux/usb/typec.h>
#include <linux/usb/typec_dp.h>
#include <linux/usb/typec_mux.h>

#define IT5205_REG_CHIP_ID(x)   (0x4 + (x))
#define IT5205FN_CHIP_ID        0x35303235 /* "5025" -> "5205" */

/* MUX power down register */
#define IT5205_REG_MUXPDR        0x10
#define IT5205_MUX_POWER_DOWN    BIT(0)

/* MUX control register */
#define IT5205_REG_MUXCR         0x11
#define IT5205_POLARITY_INVERTED BIT(4)
#define IT5205_DP_USB_CTRL_MASK  GENMASK(3, 0)
#define IT5205_DP                0x0f
#define IT5205_DP_USB            0x03
#define IT5205_USB               0x07

/* Vref Select Register */
#define IT5205_REG_VSR            0x10
#define IT5205_VREF_SELECT_MASK   GENMASK(5, 4)
#define IT5205_VREF_SELECT_3_3V   0x00
#define IT5205_VREF_SELECT_OFF    0x20

/* CSBU Over Voltage Protection Register */
#define IT5205_REG_CSBUOVPSR      0x1e
#define IT5205_OVP_SELECT_MASK    GENMASK(5, 4)
#define IT5205_OVP_3_90V          0x00
#define IT5205_OVP_3_68V          0x10
#define IT5205_OVP_3_62V          0x20
#define IT5205_OVP_3_57V          0x30

/* CSBU Switch Register */
#define IT5205_REG_CSBUSR         0x22
#define IT5205_CSBUSR_SWITCH      BIT(0)

/* Interrupt Switch Register */
#define IT5205_REG_ISR            0x25
#define IT5205_ISR_CSBU_MASK      BIT(4)
#define IT5205_ISR_CSBU_OVP       BIT(0)

struct it5205 {
        struct i2c_client *client;
        struct regmap *regmap;
        struct typec_switch_dev *sw;
        struct typec_mux_dev *mux;
};

static int it5205_switch_set(struct typec_switch_dev *sw, enum typec_orientation orientation)
{
        struct it5205 *it = typec_switch_get_drvdata(sw);

        switch (orientation) {
        case TYPEC_ORIENTATION_NORMAL:
                regmap_update_bits(it->regmap, IT5205_REG_MUXCR,
                                   IT5205_POLARITY_INVERTED, 0);
                break;
        case TYPEC_ORIENTATION_REVERSE:
                regmap_update_bits(it->regmap, IT5205_REG_MUXCR,
                                   IT5205_POLARITY_INVERTED, IT5205_POLARITY_INVERTED);
                break;
        case TYPEC_ORIENTATION_NONE:
                fallthrough;
        default:
                regmap_write(it->regmap, IT5205_REG_MUXCR, 0);
                break;
        }

        return 0;
}

static int it5205_mux_set(struct typec_mux_dev *mux, struct typec_mux_state *state)
{
        struct it5205 *it = typec_mux_get_drvdata(mux);
        u8 val;

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

        switch (state->mode) {
        case TYPEC_STATE_USB:
                val = IT5205_USB;
                break;
        case TYPEC_DP_STATE_C:
                fallthrough;
        case TYPEC_DP_STATE_E:
                val = IT5205_DP;
                break;
        case TYPEC_DP_STATE_D:
                val = IT5205_DP_USB;
                break;
        case TYPEC_STATE_SAFE:
                fallthrough;
        default:
                val = 0;
                break;
        }

        return regmap_update_bits(it->regmap, IT5205_REG_MUXCR,
                                  IT5205_DP_USB_CTRL_MASK, val);
}

static irqreturn_t it5205_irq_handler(int irq, void *data)
{
        struct it5205 *it = data;
        int ret;
        u32 val;

        ret = regmap_read(it->regmap, IT5205_REG_ISR, &val);
        if (ret)
                return IRQ_NONE;

        if (val & IT5205_ISR_CSBU_OVP) {
                dev_warn(&it->client->dev, "Overvoltage detected!\n");

                /* Reset CSBU */
                regmap_update_bits(it->regmap, IT5205_REG_CSBUSR,
                                   IT5205_CSBUSR_SWITCH, 0);
                regmap_update_bits(it->regmap, IT5205_REG_CSBUSR,
                                   IT5205_CSBUSR_SWITCH, IT5205_CSBUSR_SWITCH);
        }

        return IRQ_HANDLED;
}

static void it5205_enable_ovp(struct it5205 *it)
{
        /* Select Vref 3.3v */
        regmap_update_bits(it->regmap, IT5205_REG_VSR,
                           IT5205_VREF_SELECT_MASK, IT5205_VREF_SELECT_3_3V);

        /* Trigger OVP at 3.68V */
        regmap_update_bits(it->regmap, IT5205_REG_CSBUOVPSR,
                           IT5205_OVP_SELECT_MASK, IT5205_OVP_3_68V);

        /* Unmask OVP interrupt */
        regmap_update_bits(it->regmap, IT5205_REG_ISR,
                           IT5205_ISR_CSBU_MASK, 0);

        /* Enable CSBU Interrupt */
        regmap_update_bits(it->regmap, IT5205_REG_CSBUSR,
                           IT5205_CSBUSR_SWITCH, IT5205_CSBUSR_SWITCH);
}

static const struct regmap_config it5205_regmap = {
        .max_register = 0x2f,
        .reg_bits = 8,
        .val_bits = 8,
};

static int it5205_probe(struct i2c_client *client)
{
        struct typec_switch_desc sw_desc = { };
        struct typec_mux_desc mux_desc = { };
        struct device *dev = &client->dev;
        struct it5205 *it;
        u32 val, chipid = 0;
        int i, ret;

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

        ret = devm_regulator_get_enable(dev, "vcc");
        if (ret)
                return dev_err_probe(dev, ret, "Failed to get regulator\n");

        it->client = client;

        it->regmap = devm_regmap_init_i2c(client, &it5205_regmap);
        if (IS_ERR(it->regmap))
                return dev_err_probe(dev, PTR_ERR(it->regmap),
                                     "Failed to init regmap\n");

        /* IT5205 needs a long time to power up after enabling regulator */
        msleep(50);

        /* Unset poweroff bit */
        ret = regmap_write(it->regmap, IT5205_REG_MUXPDR, 0);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to set power on\n");

        /* Read the 32 bits ChipID */
        for (i = 3; i >= 0; i--) {
                ret = regmap_read(it->regmap, IT5205_REG_CHIP_ID(i), &val);
                if (ret)
                        return ret;

                chipid |= val << (i * 8);
        }

        if (chipid != IT5205FN_CHIP_ID)
                return dev_err_probe(dev, -EINVAL,
                                     "Unknown ChipID 0x%x\n", chipid);

        /* Initialize as USB mode with default (non-inverted) polarity */
        ret = regmap_write(it->regmap, IT5205_REG_MUXCR, IT5205_USB);
        if (ret)
                return dev_err_probe(dev, ret, "Cannot set mode to USB\n");

        sw_desc.drvdata = it;
        sw_desc.fwnode = dev_fwnode(dev);
        sw_desc.set = it5205_switch_set;

        it->sw = typec_switch_register(dev, &sw_desc);
        if (IS_ERR(it->sw))
                return dev_err_probe(dev, PTR_ERR(it->sw),
                                     "failed to register typec switch\n");

        mux_desc.drvdata = it;
        mux_desc.fwnode = dev_fwnode(dev);
        mux_desc.set = it5205_mux_set;

        it->mux = typec_mux_register(dev, &mux_desc);
        if (IS_ERR(it->mux)) {
                typec_switch_unregister(it->sw);
                return dev_err_probe(dev, PTR_ERR(it->mux),
                                     "failed to register typec mux\n");
        }

        i2c_set_clientdata(client, it);

        if (of_property_read_bool(dev->of_node, "ite,ovp-enable") && client->irq) {
                it5205_enable_ovp(it);

                ret = devm_request_threaded_irq(dev, client->irq, NULL,
                                                it5205_irq_handler,
                                                IRQF_ONESHOT, dev_name(dev), it);
                if (ret) {
                        typec_mux_unregister(it->mux);
                        typec_switch_unregister(it->sw);
                        return dev_err_probe(dev, ret, "Failed to request irq\n");
                }
        }

        return 0;
}

static void it5205_remove(struct i2c_client *client)
{
        struct it5205 *it = i2c_get_clientdata(client);

        typec_mux_unregister(it->mux);
        typec_switch_unregister(it->sw);
}

static const struct i2c_device_id it5205_table[] = {
        { "it5205" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(i2c, it5205_table);

static const struct of_device_id it5205_of_table[] = {
        { .compatible = "ite,it5205" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, it5205_of_table);

static struct i2c_driver it5205_driver = {
        .driver = {
                .name = "it5205",
                .of_match_table = it5205_of_table,
        },
        .probe = it5205_probe,
        .remove = it5205_remove,
        .id_table = it5205_table,
};
module_i2c_driver(it5205_driver);

MODULE_AUTHOR("Tianping Fang <tianping.fang@mediatek.com>");
MODULE_AUTHOR("AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>");
MODULE_DESCRIPTION("ITE IT5205 alternate mode passive MUX driver");
MODULE_LICENSE("GPL");