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(clk: 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(dev: data->smbus.dev, err: -EINVAL,
35 fmt: "Bus frequency %d is too fast.\n",
36 frequency);
37 if (data->smbus.clk_div > 0xff)
38 return dev_err_probe(dev: data->smbus.dev, err: -EINVAL,
39 fmt: "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, size: 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, index: 0);
63 if (IS_ERR(ptr: smbus->ioaddr))
64 return PTR_ERR(ptr: smbus->ioaddr);
65
66 if (of_property_read_u32(np: dev->of_node, propname: "clock-frequency", out_value: &frequency))
67 frequency = I2C_MAX_STANDARD_MODE_FREQ;
68
69 data->clk_ref = devm_clk_get_enabled(dev, NULL);
70 if (IS_ERR(ptr: data->clk_ref))
71 return PTR_ERR(ptr: 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(dev: smbus->dev, irq: irq_num, handler: pasemi_irq_handler, irqflags: 0, devname: "pasemi_apple_i2c", dev_id: (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 = 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

source code of linux/drivers/i2c/busses/i2c-pasemi-platform.c