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https://github.com/torvalds/linux
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e826192cc2
This patch adds IRQ support to the PASemi I2C controller driver to increase the performace of I2C transactions on platforms with PASemi I2C controllers. While primarily intended for Apple silicon platforms, this patch should also help in enabling IRQ support for older PASemi hardware as well should the need arise. This version of the patch has been tested on an M1 Ultra Mac Studio, as well as an M1 MacBook Pro, and userspace launches successfully while using the IRQ path for I2C transactions. Signed-off-by: Arminder Singh <arminders208@outlook.com> Reviewed-by: Sven Peter <sven@svenpeter.dev> Reviewed-by: Hector Martin <marcan@marcan.st> Signed-off-by: Wolfram Sang <wsa@kernel.org>
129 lines
3.1 KiB
C
129 lines
3.1 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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int irq_num;
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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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irq_num = platform_get_irq(pdev, 0);
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error = devm_request_irq(smbus->dev, irq_num, pasemi_irq_handler, 0, "pasemi_apple_i2c", (void *)smbus);
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if (!error)
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smbus->use_irq = 1;
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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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