1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *
4  * Copyright (C) 2012 ARM Limited
5  */
6 
7 #include <linux/clkdev.h>
8 #include <linux/clk-provider.h>
9 #include <linux/err.h>
10 #include <linux/of.h>
11 #include <linux/platform_device.h>
12 #include <linux/slab.h>
13 #include <linux/vexpress.h>
14 
15 struct vexpress_osc {
16 	struct regmap *reg;
17 	struct clk_hw hw;
18 	unsigned long rate_min;
19 	unsigned long rate_max;
20 };
21 
22 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
23 
24 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
25 		unsigned long parent_rate)
26 {
27 	struct vexpress_osc *osc = to_vexpress_osc(hw);
28 	u32 rate;
29 
30 	regmap_read(osc->reg, 0, &rate);
31 
32 	return rate;
33 }
34 
35 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
36 		unsigned long *parent_rate)
37 {
38 	struct vexpress_osc *osc = to_vexpress_osc(hw);
39 
40 	if (osc->rate_min && rate < osc->rate_min)
41 		rate = osc->rate_min;
42 
43 	if (osc->rate_max && rate > osc->rate_max)
44 		rate = osc->rate_max;
45 
46 	return rate;
47 }
48 
49 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
50 		unsigned long parent_rate)
51 {
52 	struct vexpress_osc *osc = to_vexpress_osc(hw);
53 
54 	return regmap_write(osc->reg, 0, rate);
55 }
56 
57 static const struct clk_ops vexpress_osc_ops = {
58 	.recalc_rate = vexpress_osc_recalc_rate,
59 	.round_rate = vexpress_osc_round_rate,
60 	.set_rate = vexpress_osc_set_rate,
61 };
62 
63 
64 static int vexpress_osc_probe(struct platform_device *pdev)
65 {
66 	struct clk_init_data init;
67 	struct vexpress_osc *osc;
68 	u32 range[2];
69 	int ret;
70 
71 	osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
72 	if (!osc)
73 		return -ENOMEM;
74 
75 	osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
76 	if (IS_ERR(osc->reg))
77 		return PTR_ERR(osc->reg);
78 
79 	if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
80 			ARRAY_SIZE(range)) == 0) {
81 		osc->rate_min = range[0];
82 		osc->rate_max = range[1];
83 	}
84 
85 	if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
86 			&init.name) != 0)
87 		init.name = dev_name(&pdev->dev);
88 
89 	init.ops = &vexpress_osc_ops;
90 	init.flags = 0;
91 	init.num_parents = 0;
92 
93 	osc->hw.init = &init;
94 
95 	ret = devm_clk_hw_register(&pdev->dev, &osc->hw);
96 	if (ret < 0)
97 		return ret;
98 
99 	devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_simple_get, &osc->hw);
100 	clk_hw_set_rate_range(&osc->hw, osc->rate_min, osc->rate_max);
101 
102 	dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
103 
104 	return 0;
105 }
106 
107 static const struct of_device_id vexpress_osc_of_match[] = {
108 	{ .compatible = "arm,vexpress-osc", },
109 	{}
110 };
111 
112 static struct platform_driver vexpress_osc_driver = {
113 	.driver	= {
114 		.name = "vexpress-osc",
115 		.of_match_table = vexpress_osc_of_match,
116 	},
117 	.probe = vexpress_osc_probe,
118 };
119 
120 static int __init vexpress_osc_init(void)
121 {
122 	return platform_driver_register(&vexpress_osc_driver);
123 }
124 core_initcall(vexpress_osc_init);
125