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");
114