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 |
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(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 | |
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, 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 | |
92 | static void pasemi_platform_i2c_remove(struct platform_device *pdev) { } |
93 | |
94 | static const struct of_device_id pasemi_platform_i2c_of_match[] = { |
95 | { .compatible = "apple,t8103-i2c" }, |
96 | { .compatible = "apple,i2c" }, |
97 | {}, |
98 | }; |
99 | MODULE_DEVICE_TABLE(of, pasemi_platform_i2c_of_match); |
100 | |
101 | static 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 | }; |
109 | module_platform_driver(pasemi_platform_i2c_driver); |
110 | |
111 | MODULE_LICENSE("GPL" ); |
112 | MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>" ); |
113 | MODULE_DESCRIPTION("Apple/PASemi SMBus platform driver" ); |
114 | |