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// 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;
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(dev, NULL);
if (IS_ERR(data->clk_ref))
return PTR_ERR(data->clk_ref);
error = clk_prepare_enable(data->clk_ref);
if (error)
return error;
error = pasemi_platform_i2c_calc_clk_div(data, frequency);
if (error)
goto out_clk_disable;
smbus->adapter.dev.of_node = pdev->dev.of_node;
error = pasemi_i2c_common_probe(smbus);
if (error)
goto out_clk_disable;
platform_set_drvdata(pdev, data);
return 0;
out_clk_disable:
clk_disable_unprepare(data->clk_ref);
return error;
}
static int pasemi_platform_i2c_remove(struct platform_device *pdev)
{
struct pasemi_platform_i2c_data *data = platform_get_drvdata(pdev);
clk_disable_unprepare(data->clk_ref);
return 0;
}
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");
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