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50cc4caf JK |
1 | // SPDX-License-Identifier: GPL-2.0 |
2 | ||
3 | /* | |
4 | * Memory Mapped IO Fixed clock driver | |
5 | * | |
6 | * Copyright (C) 2018 Cadence Design Systems, Inc. | |
7 | * | |
8 | * Authors: | |
9 | * Jan Kotas <jank@cadence.com> | |
10 | */ | |
11 | ||
12 | #include <linux/clk-provider.h> | |
13 | #include <linux/of_address.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/platform_device.h> | |
16 | ||
17 | static struct clk_hw *fixed_mmio_clk_setup(struct device_node *node) | |
18 | { | |
19 | struct clk_hw *clk; | |
20 | const char *clk_name = node->name; | |
21 | void __iomem *base; | |
22 | u32 freq; | |
23 | int ret; | |
24 | ||
25 | base = of_iomap(node, 0); | |
26 | if (!base) { | |
27 | pr_err("%pOFn: failed to map address\n", node); | |
28 | return ERR_PTR(-EIO); | |
29 | } | |
30 | ||
31 | freq = readl(base); | |
32 | iounmap(base); | |
33 | of_property_read_string(node, "clock-output-names", &clk_name); | |
34 | ||
35 | clk = clk_hw_register_fixed_rate(NULL, clk_name, NULL, 0, freq); | |
36 | if (IS_ERR(clk)) { | |
37 | pr_err("%pOFn: failed to register fixed rate clock\n", node); | |
38 | return clk; | |
39 | } | |
40 | ||
41 | ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, clk); | |
42 | if (ret) { | |
43 | pr_err("%pOFn: failed to add clock provider\n", node); | |
44 | clk_hw_unregister(clk); | |
45 | clk = ERR_PTR(ret); | |
46 | } | |
47 | ||
48 | return clk; | |
49 | } | |
50 | ||
51 | static void __init of_fixed_mmio_clk_setup(struct device_node *node) | |
52 | { | |
53 | fixed_mmio_clk_setup(node); | |
54 | } | |
55 | CLK_OF_DECLARE(fixed_mmio_clk, "fixed-mmio-clock", of_fixed_mmio_clk_setup); | |
56 | ||
57 | /** | |
58 | * This is not executed when of_fixed_mmio_clk_setup succeeded. | |
59 | */ | |
60 | static int of_fixed_mmio_clk_probe(struct platform_device *pdev) | |
61 | { | |
62 | struct clk_hw *clk; | |
63 | ||
64 | clk = fixed_mmio_clk_setup(pdev->dev.of_node); | |
65 | if (IS_ERR(clk)) | |
66 | return PTR_ERR(clk); | |
67 | ||
68 | platform_set_drvdata(pdev, clk); | |
69 | ||
70 | return 0; | |
71 | } | |
72 | ||
73 | static int of_fixed_mmio_clk_remove(struct platform_device *pdev) | |
74 | { | |
75 | struct clk_hw *clk = platform_get_drvdata(pdev); | |
76 | ||
77 | of_clk_del_provider(pdev->dev.of_node); | |
78 | clk_hw_unregister_fixed_rate(clk); | |
79 | ||
80 | return 0; | |
81 | } | |
82 | ||
83 | static const struct of_device_id of_fixed_mmio_clk_ids[] = { | |
84 | { .compatible = "fixed-mmio-clock" }, | |
85 | { } | |
86 | }; | |
87 | MODULE_DEVICE_TABLE(of, of_fixed_mmio_clk_ids); | |
88 | ||
89 | static struct platform_driver of_fixed_mmio_clk_driver = { | |
90 | .driver = { | |
91 | .name = "of_fixed_mmio_clk", | |
92 | .of_match_table = of_fixed_mmio_clk_ids, | |
93 | }, | |
94 | .probe = of_fixed_mmio_clk_probe, | |
95 | .remove = of_fixed_mmio_clk_remove, | |
96 | }; | |
97 | module_platform_driver(of_fixed_mmio_clk_driver); | |
98 | ||
99 | MODULE_AUTHOR("Jan Kotas <jank@cadence.com>"); | |
100 | MODULE_DESCRIPTION("Memory Mapped IO Fixed clock driver"); | |
101 | MODULE_LICENSE("GPL v2"); |