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
vexpress_osc_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)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
vexpress_osc_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * parent_rate)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
vexpress_osc_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)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
vexpress_osc_probe(struct platform_device * pdev)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_DESCRIPTION("Clock driver for Versatile Express OSC clock generators");
123 MODULE_LICENSE("GPL v2");
124