123 lines
2.9 KiB
C
123 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2021 The Asahi Linux Contributors
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*
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* PA Semi PWRficient SMBus host driver for Apple SoCs
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*/
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#include <linux/clk.h>
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#include <linux/i2c.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/types.h>
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#include "i2c-pasemi-core.h"
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struct pasemi_platform_i2c_data {
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struct pasemi_smbus smbus;
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struct clk *clk_ref;
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};
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static int
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pasemi_platform_i2c_calc_clk_div(struct pasemi_platform_i2c_data *data,
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u32 frequency)
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{
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unsigned long clk_rate = clk_get_rate(data->clk_ref);
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if (!clk_rate)
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return -EINVAL;
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data->smbus.clk_div = DIV_ROUND_UP(clk_rate, 16 * frequency);
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if (data->smbus.clk_div < 4)
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return dev_err_probe(data->smbus.dev, -EINVAL,
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"Bus frequency %d is too fast.\n",
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frequency);
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if (data->smbus.clk_div > 0xff)
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return dev_err_probe(data->smbus.dev, -EINVAL,
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"Bus frequency %d is too slow.\n",
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frequency);
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return 0;
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}
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static int pasemi_platform_i2c_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct pasemi_platform_i2c_data *data;
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struct pasemi_smbus *smbus;
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u32 frequency;
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int error;
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data = devm_kzalloc(dev, sizeof(struct pasemi_platform_i2c_data),
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GFP_KERNEL);
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if (!data)
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return -ENOMEM;
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smbus = &data->smbus;
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smbus->dev = dev;
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smbus->ioaddr = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(smbus->ioaddr))
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return PTR_ERR(smbus->ioaddr);
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if (of_property_read_u32(dev->of_node, "clock-frequency", &frequency))
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frequency = I2C_MAX_STANDARD_MODE_FREQ;
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data->clk_ref = devm_clk_get(dev, NULL);
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if (IS_ERR(data->clk_ref))
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return PTR_ERR(data->clk_ref);
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error = clk_prepare_enable(data->clk_ref);
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if (error)
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return error;
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error = pasemi_platform_i2c_calc_clk_div(data, frequency);
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if (error)
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goto out_clk_disable;
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smbus->adapter.dev.of_node = pdev->dev.of_node;
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error = pasemi_i2c_common_probe(smbus);
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if (error)
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goto out_clk_disable;
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platform_set_drvdata(pdev, data);
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return 0;
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out_clk_disable:
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clk_disable_unprepare(data->clk_ref);
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return error;
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}
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static int pasemi_platform_i2c_remove(struct platform_device *pdev)
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{
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struct pasemi_platform_i2c_data *data = platform_get_drvdata(pdev);
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clk_disable_unprepare(data->clk_ref);
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return 0;
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}
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static const struct of_device_id pasemi_platform_i2c_of_match[] = {
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{ .compatible = "apple,t8103-i2c" },
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{ .compatible = "apple,i2c" },
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{},
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};
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MODULE_DEVICE_TABLE(of, pasemi_platform_i2c_of_match);
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static struct platform_driver pasemi_platform_i2c_driver = {
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.driver = {
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.name = "i2c-apple",
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.of_match_table = pasemi_platform_i2c_of_match,
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},
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.probe = pasemi_platform_i2c_probe,
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.remove = pasemi_platform_i2c_remove,
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};
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module_platform_driver(pasemi_platform_i2c_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
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MODULE_DESCRIPTION("Apple/PASemi SMBus platform driver");
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