/*
 * Intel Cherry Trail ACPI INT33FE pseudo device driver
 *
 * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Some Intel Cherry Trail based device which ship with Windows 10, have
 * this weird INT33FE ACPI device with a CRS table with 4 I2cSerialBusV2
 * resources, for 4 different chips attached to various i2c busses:
 * 1. The Whiskey Cove pmic, which is also described by the INT34D3 ACPI device
 * 2. Maxim MAX17047 Fuel Gauge Controller
 * 3. FUSB302 USB Type-C Controller
 * 4. PI3USB30532 USB switch
 *
 * So this driver is a stub / pseudo driver whose only purpose is to
 * instantiate i2c-clients for chips 2 - 4, so that standard i2c drivers
 * for these chips can bind to the them.
 */

#include <linux/acpi.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

#define EXPECTED_PTYPE          4

struct cht_int33fe_data {
        struct i2c_client *max17047;
        struct i2c_client *fusb302;
        struct i2c_client *pi3usb30532;
        /* Contain a list-head must be per device */
        struct device_connection connections[3];
};

/*
 * Grrr I severly dislike buggy BIOS-es. At least one BIOS enumerates
 * the max17047 both through the INT33FE ACPI device (it is right there
 * in the resources table) as well as through a separate MAX17047 device.
 *
 * These helpers are used to work around this by checking if an i2c-client
 * for the max17047 has already been registered.
 */
static int cht_int33fe_check_for_max17047(struct device *dev, void *data)
{
        struct i2c_client **max17047 = data;
        struct acpi_device *adev;
        const char *hid;

        adev = ACPI_COMPANION(dev);
        if (!adev)
                return 0;

        hid = acpi_device_hid(adev);

        /* The MAX17047 ACPI node doesn't have an UID, so we don't check that */
        if (strcmp(hid, "MAX17047"))
                return 0;

        *max17047 = to_i2c_client(dev);
        return 1;
}

static struct i2c_client *cht_int33fe_find_max17047(void)
{
        struct i2c_client *max17047 = NULL;

        i2c_for_each_dev(&max17047, cht_int33fe_check_for_max17047);
        return max17047;
}

static const char * const max17047_suppliers[] = { "bq24190-charger" };

static const struct property_entry max17047_props[] = {
        PROPERTY_ENTRY_STRING_ARRAY("supplied-from", max17047_suppliers),
        { }
};

static const struct property_entry fusb302_props[] = {
        PROPERTY_ENTRY_STRING("fcs,extcon-name", "cht_wcove_pwrsrc"),
        PROPERTY_ENTRY_U32("fcs,max-sink-microvolt", 12000000),
        PROPERTY_ENTRY_U32("fcs,max-sink-microamp",   3000000),
        PROPERTY_ENTRY_U32("fcs,max-sink-microwatt", 36000000),
        { }
};

static int cht_int33fe_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct i2c_board_info board_info;
        struct cht_int33fe_data *data;
        struct i2c_client *max17047;
        struct regulator *regulator;
        unsigned long long ptyp;
        acpi_status status;
        int fusb302_irq;
        int ret;

        status = acpi_evaluate_integer(ACPI_HANDLE(dev), "PTYP", NULL, &ptyp);
        if (ACPI_FAILURE(status)) {
                dev_err(dev, "Error getting PTYPE\n");
                return -ENODEV;
        }

        /*
         * The same ACPI HID is used for different configurations check PTYP
         * to ensure that we are dealing with the expected config.
         */
        if (ptyp != EXPECTED_PTYPE)
                return -ENODEV;

        /* Check presence of INT34D3 (hardware-rev 3) expected for ptype == 4 */
        if (!acpi_dev_present("INT34D3", "1", 3)) {
                dev_err(dev, "Error PTYPE == %d, but no INT34D3 device\n",
                        EXPECTED_PTYPE);
                return -ENODEV;
        }

        /*
         * We expect the WC PMIC to be paired with a TI bq24292i charger-IC.
         * We check for the bq24292i vbus regulator here, this has 2 purposes:
         * 1) The bq24292i allows charging with up to 12V, setting the fusb302's
         *    max-snk voltage to 12V with another charger-IC is not good.
         * 2) For the fusb302 driver to get the bq24292i vbus regulator, the
         *    regulator-map, which is part of the bq24292i regulator_init_data,
         *    must be registered before the fusb302 is instantiated, otherwise
         *    it will end up with a dummy-regulator.
         * Note "cht_wc_usb_typec_vbus" comes from the regulator_init_data
         * which is defined in i2c-cht-wc.c from where the bq24292i i2c-client
         * gets instantiated. We use regulator_get_optional here so that we
         * don't end up getting a dummy-regulator ourselves.
         */
        regulator = regulator_get_optional(dev, "cht_wc_usb_typec_vbus");
        if (IS_ERR(regulator)) {
                ret = PTR_ERR(regulator);
                return (ret == -ENODEV) ? -EPROBE_DEFER : ret;
        }
        regulator_put(regulator);

        /* The FUSB302 uses the irq at index 1 and is the only irq user */
        fusb302_irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 1);
        if (fusb302_irq < 0) {
                if (fusb302_irq != -EPROBE_DEFER)
                        dev_err(dev, "Error getting FUSB302 irq\n");
                return fusb302_irq;
        }

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

        /* Work around BIOS bug, see comment on cht_int33fe_find_max17047 */
        max17047 = cht_int33fe_find_max17047();
        if (max17047) {
                /* Pre-existing i2c-client for the max17047, add device-props */
                ret = device_add_properties(&max17047->dev, max17047_props);
                if (ret)
                        return ret;
                /* And re-probe to get the new device-props applied. */
                ret = device_reprobe(&max17047->dev);
                if (ret)
                        dev_warn(dev, "Reprobing max17047 error: %d\n", ret);
        } else {
                memset(&board_info, 0, sizeof(board_info));
                strlcpy(board_info.type, "max17047", I2C_NAME_SIZE);
                board_info.dev_name = "max17047";
                board_info.properties = max17047_props;
                data->max17047 = i2c_acpi_new_device(dev, 1, &board_info);
                if (!data->max17047)
                        return -EPROBE_DEFER; /* Wait for i2c-adapter to load */
        }

        data->connections[0].endpoint[0] = "i2c-fusb302";
        data->connections[0].endpoint[1] = "i2c-pi3usb30532";
        data->connections[0].id = "typec-switch";
        data->connections[1].endpoint[0] = "i2c-fusb302";
        data->connections[1].endpoint[1] = "i2c-pi3usb30532";
        data->connections[1].id = "typec-mux";
        data->connections[2].endpoint[0] = "i2c-fusb302";
        data->connections[2].endpoint[1] = "intel_xhci_usb_sw-role-switch";
        data->connections[2].id = "usb-role-switch";

        device_connection_add(&data->connections[0]);
        device_connection_add(&data->connections[1]);
        device_connection_add(&data->connections[2]);

        memset(&board_info, 0, sizeof(board_info));
        strlcpy(board_info.type, "typec_fusb302", I2C_NAME_SIZE);
        board_info.dev_name = "fusb302";
        board_info.properties = fusb302_props;
        board_info.irq = fusb302_irq;

        data->fusb302 = i2c_acpi_new_device(dev, 2, &board_info);
        if (!data->fusb302)
                goto out_unregister_max17047;

        memset(&board_info, 0, sizeof(board_info));
        board_info.dev_name = "pi3usb30532";
        strlcpy(board_info.type, "pi3usb30532", I2C_NAME_SIZE);

        data->pi3usb30532 = i2c_acpi_new_device(dev, 3, &board_info);
        if (!data->pi3usb30532)
                goto out_unregister_fusb302;

        i2c_set_clientdata(client, data);

        return 0;

out_unregister_fusb302:
        i2c_unregister_device(data->fusb302);

out_unregister_max17047:
        if (data->max17047)
                i2c_unregister_device(data->max17047);

        device_connection_remove(&data->connections[2]);
        device_connection_remove(&data->connections[1]);
        device_connection_remove(&data->connections[0]);

        return -EPROBE_DEFER; /* Wait for the i2c-adapter to load */
}

static int cht_int33fe_remove(struct i2c_client *i2c)
{
        struct cht_int33fe_data *data = i2c_get_clientdata(i2c);

        i2c_unregister_device(data->pi3usb30532);
        i2c_unregister_device(data->fusb302);
        if (data->max17047)
                i2c_unregister_device(data->max17047);

        device_connection_remove(&data->connections[2]);
        device_connection_remove(&data->connections[1]);
        device_connection_remove(&data->connections[0]);

        return 0;
}

static const struct i2c_device_id cht_int33fe_i2c_id[] = {
        { }
};
MODULE_DEVICE_TABLE(i2c, cht_int33fe_i2c_id);

static const struct acpi_device_id cht_int33fe_acpi_ids[] = {
        { "INT33FE", },
        { }
};
MODULE_DEVICE_TABLE(acpi, cht_int33fe_acpi_ids);

static struct i2c_driver cht_int33fe_driver = {
        .driver = {
                .name = "Intel Cherry Trail ACPI INT33FE driver",
                .acpi_match_table = ACPI_PTR(cht_int33fe_acpi_ids),
        },
        .probe_new = cht_int33fe_probe,
        .remove = cht_int33fe_remove,
        .id_table = cht_int33fe_i2c_id,
        .disable_i2c_core_irq_mapping = true,
};

module_i2c_driver(cht_int33fe_driver);

MODULE_DESCRIPTION("Intel Cherry Trail ACPI INT33FE pseudo device driver");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_LICENSE("GPL");