// SPDX-License-Identifier: GPL-2.0-only
/*
 *  i2c-versatile.c
 *
 *  Copyright (C) 2006 ARM Ltd.
 *  written by Russell King, Deep Blue Solutions Ltd.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-bit.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/io.h>

#define I2C_CONTROL     0x00
#define I2C_CONTROLS    0x00
#define I2C_CONTROLC    0x04
#define SCL             (1 << 0)
#define SDA             (1 << 1)

struct i2c_versatile {
        struct i2c_adapter       adap;
        struct i2c_algo_bit_data algo;
        void __iomem             *base;
};

static void i2c_versatile_setsda(void *data, int state)
{
        struct i2c_versatile *i2c = data;

        writel(SDA, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
}

static void i2c_versatile_setscl(void *data, int state)
{
        struct i2c_versatile *i2c = data;

        writel(SCL, i2c->base + (state ? I2C_CONTROLS : I2C_CONTROLC));
}

static int i2c_versatile_getsda(void *data)
{
        struct i2c_versatile *i2c = data;
        return !!(readl(i2c->base + I2C_CONTROL) & SDA);
}

static int i2c_versatile_getscl(void *data)
{
        struct i2c_versatile *i2c = data;
        return !!(readl(i2c->base + I2C_CONTROL) & SCL);
}

static const struct i2c_algo_bit_data i2c_versatile_algo = {
        .setsda = i2c_versatile_setsda,
        .setscl = i2c_versatile_setscl,
        .getsda = i2c_versatile_getsda,
        .getscl = i2c_versatile_getscl,
        .udelay = 30,
        .timeout = HZ,
};

static int i2c_versatile_probe(struct platform_device *dev)
{
        struct i2c_versatile *i2c;
        int ret;

        i2c = devm_kzalloc(&dev->dev, sizeof(struct i2c_versatile), GFP_KERNEL);
        if (!i2c)
                return -ENOMEM;

        i2c->base = devm_platform_get_and_ioremap_resource(dev, 0, NULL);
        if (IS_ERR(i2c->base))
                return PTR_ERR(i2c->base);

        writel(SCL | SDA, i2c->base + I2C_CONTROLS);

        i2c->adap.owner = THIS_MODULE;
        strscpy(i2c->adap.name, "Versatile I2C adapter", sizeof(i2c->adap.name));
        i2c->adap.algo_data = &i2c->algo;
        i2c->adap.dev.parent = &dev->dev;
        i2c->adap.dev.of_node = dev->dev.of_node;
        i2c->algo = i2c_versatile_algo;
        i2c->algo.data = i2c;

        i2c->adap.nr = dev->id;
        ret = i2c_bit_add_numbered_bus(&i2c->adap);
        if (ret < 0)
                return ret;

        platform_set_drvdata(dev, i2c);

        return 0;
}

static void i2c_versatile_remove(struct platform_device *dev)
{
        struct i2c_versatile *i2c = platform_get_drvdata(dev);

        i2c_del_adapter(&i2c->adap);
}

static const struct of_device_id i2c_versatile_match[] = {
        { .compatible = "arm,versatile-i2c", },
        {},
};
MODULE_DEVICE_TABLE(of, i2c_versatile_match);

static struct platform_driver i2c_versatile_driver = {
        .probe          = i2c_versatile_probe,
        .remove         = i2c_versatile_remove,
        .driver         = {
                .name   = "versatile-i2c",
                .of_match_table = i2c_versatile_match,
        },
};

static int __init i2c_versatile_init(void)
{
        return platform_driver_register(&i2c_versatile_driver);
}

static void __exit i2c_versatile_exit(void)
{
        platform_driver_unregister(&i2c_versatile_driver);
}

subsys_initcall(i2c_versatile_init);
module_exit(i2c_versatile_exit);

MODULE_DESCRIPTION("ARM Versatile I2C bus driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:versatile-i2c");