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/module.h>
11 #include <linux/of.h>
12 #include <linux/platform_device.h>
13 #include <linux/slab.h>
14 #include <linux/vexpress.h>
15 
16 struct vexpress_osc {
17 	struct regmap *reg;
18 	struct clk_hw hw;
19 	unsigned long rate_min;
20 	unsigned long rate_max;
21 };
22 
23 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
24 
25 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
26 		unsigned long parent_rate)
27 {
28 	struct vexpress_osc *osc = to_vexpress_osc(hw);
29 	u32 rate;
30 
31 	regmap_read(osc->reg, 0, &rate);
32 
33 	return rate;
34 }
35 
36 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
37 		unsigned long *parent_rate)
38 {
39 	struct vexpress_osc *osc = to_vexpress_osc(hw);
40 
41 	if (osc->rate_min && rate < osc->rate_min)
42 		rate = osc->rate_min;
43 
44 	if (osc->rate_max && rate > osc->rate_max)
45 		rate = osc->rate_max;
46 
47 	return rate;
48 }
49 
50 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
51 		unsigned long parent_rate)
52 {
53 	struct vexpress_osc *osc = to_vexpress_osc(hw);
54 
55 	return regmap_write(osc->reg, 0, rate);
56 }
57 
58 static const struct clk_ops vexpress_osc_ops = {
59 	.recalc_rate = vexpress_osc_recalc_rate,
60 	.round_rate = vexpress_osc_round_rate,
61 	.set_rate = vexpress_osc_set_rate,
62 };
63 
64 
65 static int vexpress_osc_probe(struct platform_device *pdev)
66 {
67 	struct clk_init_data init;
68 	struct vexpress_osc *osc;
69 	u32 range[2];
70 	int ret;
71 
72 	osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
73 	if (!osc)
74 		return -ENOMEM;
75 
76 	osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
77 	if (IS_ERR(osc->reg))
78 		return PTR_ERR(osc->reg);
79 
80 	if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
81 			ARRAY_SIZE(range)) == 0) {
82 		osc->rate_min = range[0];
83 		osc->rate_max = range[1];
84 	}
85 
86 	if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
87 			&init.name) != 0)
88 		init.name = dev_name(&pdev->dev);
89 
90 	init.ops = &vexpress_osc_ops;
91 	init.flags = 0;
92 	init.num_parents = 0;
93 
94 	osc->hw.init = &init;
95 
96 	ret = devm_clk_hw_register(&pdev->dev, &osc->hw);
97 	if (ret < 0)
98 		return ret;
99 
100 	devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_simple_get, &osc->hw);
101 	clk_hw_set_rate_range(&osc->hw, osc->rate_min, osc->rate_max);
102 
103 	dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
104 
105 	return 0;
106 }
107 
108 static const struct of_device_id vexpress_osc_of_match[] = {
109 	{ .compatible = "arm,vexpress-osc", },
110 	{}
111 };
112 MODULE_DEVICE_TABLE(of, vexpress_osc_of_match);
113 
114 static struct platform_driver vexpress_osc_driver = {
115 	.driver	= {
116 		.name = "vexpress-osc",
117 		.of_match_table = vexpress_osc_of_match,
118 	},
119 	.probe = vexpress_osc_probe,
120 };
121 module_platform_driver(vexpress_osc_driver);
122 MODULE_LICENSE("GPL v2");
123