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 #define pr_fmt(fmt) "vexpress-osc: " fmt
15 
16 #include <linux/clkdev.h>
17 #include <linux/clk-provider.h>
18 #include <linux/err.h>
19 #include <linux/of.h>
20 #include <linux/platform_device.h>
21 #include <linux/slab.h>
22 #include <linux/vexpress.h>
23 
24 struct vexpress_osc {
25 	struct vexpress_config_func *func;
26 	struct clk_hw hw;
27 	unsigned long rate_min;
28 	unsigned long rate_max;
29 };
30 
31 #define to_vexpress_osc(osc) container_of(osc, struct vexpress_osc, hw)
32 
33 static unsigned long vexpress_osc_recalc_rate(struct clk_hw *hw,
34 		unsigned long parent_rate)
35 {
36 	struct vexpress_osc *osc = to_vexpress_osc(hw);
37 	u32 rate;
38 
39 	vexpress_config_read(osc->func, 0, &rate);
40 
41 	return rate;
42 }
43 
44 static long vexpress_osc_round_rate(struct clk_hw *hw, unsigned long rate,
45 		unsigned long *parent_rate)
46 {
47 	struct vexpress_osc *osc = to_vexpress_osc(hw);
48 
49 	if (WARN_ON(osc->rate_min && rate < osc->rate_min))
50 		rate = osc->rate_min;
51 
52 	if (WARN_ON(osc->rate_max && rate > osc->rate_max))
53 		rate = osc->rate_max;
54 
55 	return rate;
56 }
57 
58 static int vexpress_osc_set_rate(struct clk_hw *hw, unsigned long rate,
59 		unsigned long parent_rate)
60 {
61 	struct vexpress_osc *osc = to_vexpress_osc(hw);
62 
63 	return vexpress_config_write(osc->func, 0, rate);
64 }
65 
66 static struct clk_ops vexpress_osc_ops = {
67 	.recalc_rate = vexpress_osc_recalc_rate,
68 	.round_rate = vexpress_osc_round_rate,
69 	.set_rate = vexpress_osc_set_rate,
70 };
71 
72 
73 struct clk * __init vexpress_osc_setup(struct device *dev)
74 {
75 	struct clk_init_data init;
76 	struct vexpress_osc *osc = kzalloc(sizeof(*osc), GFP_KERNEL);
77 
78 	if (!osc)
79 		return NULL;
80 
81 	osc->func = vexpress_config_func_get_by_dev(dev);
82 	if (!osc->func) {
83 		kfree(osc);
84 		return NULL;
85 	}
86 
87 	init.name = dev_name(dev);
88 	init.ops = &vexpress_osc_ops;
89 	init.flags = CLK_IS_ROOT;
90 	init.num_parents = 0;
91 	osc->hw.init = &init;
92 
93 	return clk_register(NULL, &osc->hw);
94 }
95 
96 void __init vexpress_osc_of_setup(struct device_node *node)
97 {
98 	struct clk_init_data init;
99 	struct vexpress_osc *osc;
100 	struct clk *clk;
101 	u32 range[2];
102 
103 	osc = kzalloc(sizeof(*osc), GFP_KERNEL);
104 	if (!osc)
105 		return;
106 
107 	osc->func = vexpress_config_func_get_by_node(node);
108 	if (!osc->func) {
109 		pr_err("Failed to obtain config func for node '%s'!\n",
110 				node->full_name);
111 		goto error;
112 	}
113 
114 	if (of_property_read_u32_array(node, "freq-range", range,
115 			ARRAY_SIZE(range)) == 0) {
116 		osc->rate_min = range[0];
117 		osc->rate_max = range[1];
118 	}
119 
120 	of_property_read_string(node, "clock-output-names", &init.name);
121 	if (!init.name)
122 		init.name = node->full_name;
123 
124 	init.ops = &vexpress_osc_ops;
125 	init.flags = CLK_IS_ROOT;
126 	init.num_parents = 0;
127 
128 	osc->hw.init = &init;
129 
130 	clk = clk_register(NULL, &osc->hw);
131 	if (IS_ERR(clk)) {
132 		pr_err("Failed to register clock '%s'!\n", init.name);
133 		goto error;
134 	}
135 
136 	of_clk_add_provider(node, of_clk_src_simple_get, clk);
137 
138 	pr_debug("Registered clock '%s'\n", init.name);
139 
140 	return;
141 
142 error:
143 	if (osc->func)
144 		vexpress_config_func_put(osc->func);
145 	kfree(osc);
146 }
147 CLK_OF_DECLARE(vexpress_soc, "arm,vexpress-osc", vexpress_osc_of_setup);
148