// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2021 The Asahi Linux Contributors
 *
 * PA Semi PWRficient SMBus host driver for Apple SoCs
 */

#include <linux/clk.h>
#include <linux/i2c.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/types.h>

#include "i2c-pasemi-core.h"

struct pasemi_platform_i2c_data {
        struct pasemi_smbus smbus;
        struct clk *clk_ref;
};

static int
pasemi_platform_i2c_calc_clk_div(struct pasemi_platform_i2c_data *data,
                                 u32 frequency)
{
        unsigned long clk_rate = clk_get_rate(data->clk_ref);

        if (!clk_rate)
                return -EINVAL;

        data->smbus.clk_div = DIV_ROUND_UP(clk_rate, 16 * frequency);
        if (data->smbus.clk_div < 4)
                return dev_err_probe(data->smbus.dev, -EINVAL,
                                     "Bus frequency %d is too fast.\n",
                                     frequency);
        if (data->smbus.clk_div > 0xff)
                return dev_err_probe(data->smbus.dev, -EINVAL,
                                     "Bus frequency %d is too slow.\n",
                                     frequency);

        return 0;
}

static int pasemi_platform_i2c_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct pasemi_platform_i2c_data *data;
        struct pasemi_smbus *smbus;
        u32 frequency;
        int error;
        int irq_num;

        data = devm_kzalloc(dev, sizeof(struct pasemi_platform_i2c_data),
                            GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        smbus = &data->smbus;
        smbus->dev = dev;

        smbus->ioaddr = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(smbus->ioaddr))
                return PTR_ERR(smbus->ioaddr);

        if (of_property_read_u32(dev->of_node, "clock-frequency", &frequency))
                frequency = I2C_MAX_STANDARD_MODE_FREQ;

        data->clk_ref = devm_clk_get_enabled(dev, NULL);
        if (IS_ERR(data->clk_ref))
                return PTR_ERR(data->clk_ref);

        error = pasemi_platform_i2c_calc_clk_div(data, frequency);
        if (error)
                return error;

        smbus->adapter.dev.of_node = pdev->dev.of_node;
        error = pasemi_i2c_common_probe(smbus);
        if (error)
                return error;

        irq_num = platform_get_irq(pdev, 0);
        error = devm_request_irq(smbus->dev, irq_num, pasemi_irq_handler, 0, "pasemi_apple_i2c", (void *)smbus);

        if (!error)
                smbus->use_irq = 1;
        platform_set_drvdata(pdev, data);

        return 0;
}

static void pasemi_platform_i2c_remove(struct platform_device *pdev) { }

static const struct of_device_id pasemi_platform_i2c_of_match[] = {
        { .compatible = "apple,t8103-i2c" },
        { .compatible = "apple,i2c" },
        {},
};
MODULE_DEVICE_TABLE(of, pasemi_platform_i2c_of_match);

static struct platform_driver pasemi_platform_i2c_driver = {
        .driver = {
                .name                   = "i2c-apple",
                .of_match_table         = pasemi_platform_i2c_of_match,
        },
        .probe  = pasemi_platform_i2c_probe,
        .remove = pasemi_platform_i2c_remove,
};
module_platform_driver(pasemi_platform_i2c_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
MODULE_DESCRIPTION("Apple/PASemi SMBus platform driver");