// 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");