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
18 struct pasemi_platform_i2c_data {
19 struct pasemi_smbus smbus;
20 struct clk *clk_ref;
21 };
22
23 static int
pasemi_platform_i2c_calc_clk_div(struct pasemi_platform_i2c_data * data,u32 frequency)24 pasemi_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
pasemi_platform_i2c_probe(struct platform_device * pdev)45 static 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(dev, NULL);
70 if (IS_ERR(data->clk_ref))
71 return PTR_ERR(data->clk_ref);
72
73 error = clk_prepare_enable(data->clk_ref);
74 if (error)
75 return error;
76
77 error = pasemi_platform_i2c_calc_clk_div(data, frequency);
78 if (error)
79 goto out_clk_disable;
80
81 smbus->adapter.dev.of_node = pdev->dev.of_node;
82 error = pasemi_i2c_common_probe(smbus);
83 if (error)
84 goto out_clk_disable;
85
86 irq_num = platform_get_irq(pdev, 0);
87 error = devm_request_irq(smbus->dev, irq_num, pasemi_irq_handler, 0, "pasemi_apple_i2c", (void *)smbus);
88
89 if (!error)
90 smbus->use_irq = 1;
91 platform_set_drvdata(pdev, data);
92
93 return 0;
94
95 out_clk_disable:
96 clk_disable_unprepare(data->clk_ref);
97
98 return error;
99 }
100
pasemi_platform_i2c_remove(struct platform_device * pdev)101 static int pasemi_platform_i2c_remove(struct platform_device *pdev)
102 {
103 struct pasemi_platform_i2c_data *data = platform_get_drvdata(pdev);
104
105 clk_disable_unprepare(data->clk_ref);
106 return 0;
107 }
108
109 static const struct of_device_id pasemi_platform_i2c_of_match[] = {
110 { .compatible = "apple,t8103-i2c" },
111 { .compatible = "apple,i2c" },
112 {},
113 };
114 MODULE_DEVICE_TABLE(of, pasemi_platform_i2c_of_match);
115
116 static struct platform_driver pasemi_platform_i2c_driver = {
117 .driver = {
118 .name = "i2c-apple",
119 .of_match_table = pasemi_platform_i2c_of_match,
120 },
121 .probe = pasemi_platform_i2c_probe,
122 .remove = pasemi_platform_i2c_remove,
123 };
124 module_platform_driver(pasemi_platform_i2c_driver);
125
126 MODULE_LICENSE("GPL");
127 MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
128 MODULE_DESCRIPTION("Apple/PASemi SMBus platform driver");
129