1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Copyright (C) 2021 The Asahi Linux Contributors
  4 *
  5 * PA Semi PWRficient SMBus host driver for Apple SoCs
  6 */
  7
  8#include <linux/clk.h>
  9#include <linux/i2c.h>
 10#include <linux/io.h>
 11#include <linux/kernel.h>
 12#include <linux/module.h>
 13#include <linux/platform_device.h>
 14#include <linux/types.h>
 15
 16#include "i2c-pasemi-core.h"
 17
 18struct pasemi_platform_i2c_data {
 19	struct pasemi_smbus smbus;
 20	struct clk *clk_ref;
 21};
 22
 23static int
 24pasemi_platform_i2c_calc_clk_div(struct pasemi_platform_i2c_data *data,
 25				 u32 frequency)
 26{
 27	unsigned long clk_rate = clk_get_rate(data->clk_ref);
 28
 29	if (!clk_rate)
 30		return -EINVAL;
 31
 32	data->smbus.clk_div = DIV_ROUND_UP(clk_rate, 16 * frequency);
 33	if (data->smbus.clk_div < 4)
 34		return dev_err_probe(data->smbus.dev, -EINVAL,
 35				     "Bus frequency %d is too fast.\n",
 36				     frequency);
 37	if (data->smbus.clk_div > 0xff)
 38		return dev_err_probe(data->smbus.dev, -EINVAL,
 39				     "Bus frequency %d is too slow.\n",
 40				     frequency);
 41
 42	return 0;
 43}
 44
 45static int pasemi_platform_i2c_probe(struct platform_device *pdev)
 46{
 47	struct device *dev = &pdev->dev;
 48	struct pasemi_platform_i2c_data *data;
 49	struct pasemi_smbus *smbus;
 50	u32 frequency;
 51	int error;
 52	int irq_num;
 53
 54	data = devm_kzalloc(dev, sizeof(struct pasemi_platform_i2c_data),
 55			    GFP_KERNEL);
 56	if (!data)
 57		return -ENOMEM;
 58
 59	smbus = &data->smbus;
 60	smbus->dev = dev;
 61
 62	smbus->ioaddr = devm_platform_ioremap_resource(pdev, 0);
 63	if (IS_ERR(smbus->ioaddr))
 64		return PTR_ERR(smbus->ioaddr);
 65
 66	if (of_property_read_u32(dev->of_node, "clock-frequency", &frequency))
 67		frequency = I2C_MAX_STANDARD_MODE_FREQ;
 68
 69	data->clk_ref = devm_clk_get_enabled(dev, NULL);
 70	if (IS_ERR(data->clk_ref))
 71		return PTR_ERR(data->clk_ref);
 72
 73	error = pasemi_platform_i2c_calc_clk_div(data, frequency);
 74	if (error)
 75		return error;
 76
 77	smbus->adapter.dev.of_node = pdev->dev.of_node;
 78	error = pasemi_i2c_common_probe(smbus);
 79	if (error)
 80		return error;
 81
 82	irq_num = platform_get_irq(pdev, 0);
 83	error = devm_request_irq(smbus->dev, irq_num, pasemi_irq_handler, 0, "pasemi_apple_i2c", (void *)smbus);
 84
 85	if (!error)
 86		smbus->use_irq = 1;
 87	platform_set_drvdata(pdev, data);
 88
 89	return 0;
 90}
 91
 92static void pasemi_platform_i2c_remove(struct platform_device *pdev) { }
 93
 94static const struct of_device_id pasemi_platform_i2c_of_match[] = {
 95	{ .compatible = "apple,t8103-i2c" },
 96	{ .compatible = "apple,i2c" },
 97	{},
 98};
 99MODULE_DEVICE_TABLE(of, pasemi_platform_i2c_of_match);
100
101static struct platform_driver pasemi_platform_i2c_driver = {
102	.driver	= {
103		.name			= "i2c-apple",
104		.of_match_table		= pasemi_platform_i2c_of_match,
105	},
106	.probe	= pasemi_platform_i2c_probe,
107	.remove_new = pasemi_platform_i2c_remove,
108};
109module_platform_driver(pasemi_platform_i2c_driver);
110
111MODULE_LICENSE("GPL");
112MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
113MODULE_DESCRIPTION("Apple/PASemi SMBus platform driver");