1 /*
2  * This program is free software; you can redistribute it and/or modify
3  * it under the terms of the GNU General Public License version 2 as
4  * published by the Free Software Foundation.
5  *
6  * This program is distributed in the hope that it will be useful,
7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
9  * GNU General Public License for more details.
10  *
11  * Copyright (C) 2012 ARM Limited
12  */
13 
14 #include <linux/clkdev.h>
15 #include <linux/clk-provider.h>
16 #include <linux/err.h>
17 #include <linux/of.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/vexpress.h>
21 
22 struct vexpress_osc {
23 	struct regmap *reg;
24 	struct clk_hw hw;
25 	unsigned long rate_min;
26 	unsigned long rate_max;
27 };
28 
29 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
30 
31 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
32 		unsigned long parent_rate)
33 {
34 	struct vexpress_osc *osc = to_vexpress_osc(hw);
35 	u32 rate;
36 
37 	regmap_read(osc->reg, 0, &rate);
38 
39 	return rate;
40 }
41 
42 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
43 		unsigned long *parent_rate)
44 {
45 	struct vexpress_osc *osc = to_vexpress_osc(hw);
46 
47 	if (WARN_ON(osc->rate_min && rate < osc->rate_min))
48 		rate = osc->rate_min;
49 
50 	if (WARN_ON(osc->rate_max && rate > osc->rate_max))
51 		rate = osc->rate_max;
52 
53 	return rate;
54 }
55 
56 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
57 		unsigned long parent_rate)
58 {
59 	struct vexpress_osc *osc = to_vexpress_osc(hw);
60 
61 	return regmap_write(osc->reg, 0, rate);
62 }
63 
64 static struct clk_ops vexpress_osc_ops = {
65 	.recalc_rate = vexpress_osc_recalc_rate,
66 	.round_rate = vexpress_osc_round_rate,
67 	.set_rate = vexpress_osc_set_rate,
68 };
69 
70 
71 static int vexpress_osc_probe(struct platform_device *pdev)
72 {
73 	struct clk_lookup *cl = pdev->dev.platform_data; /* Non-DT lookup */
74 	struct clk_init_data init;
75 	struct vexpress_osc *osc;
76 	struct clk *clk;
77 	u32 range[2];
78 
79 	osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
80 	if (!osc)
81 		return -ENOMEM;
82 
83 	osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
84 	if (IS_ERR(osc->reg))
85 		return PTR_ERR(osc->reg);
86 
87 	if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
88 			ARRAY_SIZE(range)) == 0) {
89 		osc->rate_min = range[0];
90 		osc->rate_max = range[1];
91 	}
92 
93 	if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
94 			&init.name) != 0)
95 		init.name = dev_name(&pdev->dev);
96 
97 	init.ops = &vexpress_osc_ops;
98 	init.flags = CLK_IS_ROOT;
99 	init.num_parents = 0;
100 
101 	osc->hw.init = &init;
102 
103 	clk = clk_register(NULL, &osc->hw);
104 	if (IS_ERR(clk))
105 		return PTR_ERR(clk);
106 
107 	of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
108 
109 	/* Only happens for non-DT cases */
110 	if (cl) {
111 		cl->clk = clk;
112 		clkdev_add(cl);
113 	}
114 
115 	dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
116 
117 	return 0;
118 }
119 
120 static struct of_device_id vexpress_osc_of_match[] = {
121 	{ .compatible = "arm,vexpress-osc", },
122 	{}
123 };
124 
125 static struct platform_driver vexpress_osc_driver = {
126 	.driver	= {
127 		.name = "vexpress-osc",
128 		.of_match_table = vexpress_osc_of_match,
129 	},
130 	.probe = vexpress_osc_probe,
131 };
132 
133 static int __init vexpress_osc_init(void)
134 {
135 	return platform_driver_register(&vexpress_osc_driver);
136 }
137 core_initcall(vexpress_osc_init);
138