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
22struct 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
31static 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
42static 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
56static 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
64static 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
71static int vexpress_osc_probe(struct platform_device *pdev)
72{
73	struct clk_init_data init;
74	struct vexpress_osc *osc;
75	struct clk *clk;
76	u32 range[2];
77
78	osc = devm_kzalloc(&pdev->dev, sizeof(*osc), GFP_KERNEL);
79	if (!osc)
80		return -ENOMEM;
81
82	osc->reg = devm_regmap_init_vexpress_config(&pdev->dev);
83	if (IS_ERR(osc->reg))
84		return PTR_ERR(osc->reg);
85
86	if (of_property_read_u32_array(pdev->dev.of_node, "freq-range", range,
87			ARRAY_SIZE(range)) == 0) {
88		osc->rate_min = range[0];
89		osc->rate_max = range[1];
90	}
91
92	if (of_property_read_string(pdev->dev.of_node, "clock-output-names",
93			&init.name) != 0)
94		init.name = dev_name(&pdev->dev);
95
96	init.ops = &vexpress_osc_ops;
97	init.flags = CLK_IS_ROOT;
98	init.num_parents = 0;
99
100	osc->hw.init = &init;
101
102	clk = clk_register(NULL, &osc->hw);
103	if (IS_ERR(clk))
104		return PTR_ERR(clk);
105
106	of_clk_add_provider(pdev->dev.of_node, of_clk_src_simple_get, clk);
107
108	dev_dbg(&pdev->dev, "Registered clock '%s'\n", init.name);
109
110	return 0;
111}
112
113static const struct of_device_id vexpress_osc_of_match[] = {
114	{ .compatible = "arm,vexpress-osc", },
115	{}
116};
117
118static struct platform_driver vexpress_osc_driver = {
119	.driver	= {
120		.name = "vexpress-osc",
121		.of_match_table = vexpress_osc_of_match,
122	},
123	.probe = vexpress_osc_probe,
124};
125
126static int __init vexpress_osc_init(void)
127{
128	return platform_driver_register(&vexpress_osc_driver);
129}
130core_initcall(vexpress_osc_init);
131