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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com> | |
4 | * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org> | |
5 | * | |
6 | * Fixed rate clock implementation | |
7 | */ | |
8 | ||
9 | #include <linux/clk-provider.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/io.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/of.h> | |
15 | #include <linux/platform_device.h> | |
16 | ||
17 | /* | |
18 | * DOC: basic fixed-rate clock that cannot gate | |
19 | * | |
20 | * Traits of this clock: | |
21 | * prepare - clk_(un)prepare only ensures parents are prepared | |
22 | * enable - clk_enable only ensures parents are enabled | |
23 | * rate - rate is always a fixed value. No clk_set_rate support | |
24 | * parent - fixed parent. No clk_set_parent support | |
25 | */ | |
26 | ||
27 | static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw, | |
28 | unsigned long parent_rate) | |
29 | { | |
30 | return to_clk_fixed_rate(hw)->fixed_rate; | |
31 | } | |
32 | ||
33 | static unsigned long clk_fixed_rate_recalc_accuracy(struct clk_hw *hw, | |
34 | unsigned long parent_accuracy) | |
35 | { | |
36 | return to_clk_fixed_rate(hw)->fixed_accuracy; | |
37 | } | |
38 | ||
39 | const struct clk_ops clk_fixed_rate_ops = { | |
40 | .recalc_rate = clk_fixed_rate_recalc_rate, | |
41 | .recalc_accuracy = clk_fixed_rate_recalc_accuracy, | |
42 | }; | |
43 | EXPORT_SYMBOL_GPL(clk_fixed_rate_ops); | |
44 | ||
45 | /** | |
46 | * clk_hw_register_fixed_rate_with_accuracy - register fixed-rate clock with | |
47 | * the clock framework | |
48 | * @dev: device that is registering this clock | |
49 | * @name: name of this clock | |
50 | * @parent_name: name of clock's parent | |
51 | * @flags: framework-specific flags | |
52 | * @fixed_rate: non-adjustable clock rate | |
53 | * @fixed_accuracy: non-adjustable clock rate | |
54 | */ | |
55 | struct clk_hw *clk_hw_register_fixed_rate_with_accuracy(struct device *dev, | |
56 | const char *name, const char *parent_name, unsigned long flags, | |
57 | unsigned long fixed_rate, unsigned long fixed_accuracy) | |
58 | { | |
59 | struct clk_fixed_rate *fixed; | |
60 | struct clk_hw *hw; | |
61 | struct clk_init_data init; | |
62 | int ret; | |
63 | ||
64 | /* allocate fixed-rate clock */ | |
65 | fixed = kzalloc(sizeof(*fixed), GFP_KERNEL); | |
66 | if (!fixed) | |
67 | return ERR_PTR(-ENOMEM); | |
68 | ||
69 | init.name = name; | |
70 | init.ops = &clk_fixed_rate_ops; | |
71 | init.flags = flags; | |
72 | init.parent_names = (parent_name ? &parent_name: NULL); | |
73 | init.num_parents = (parent_name ? 1 : 0); | |
74 | ||
75 | /* struct clk_fixed_rate assignments */ | |
76 | fixed->fixed_rate = fixed_rate; | |
77 | fixed->fixed_accuracy = fixed_accuracy; | |
78 | fixed->hw.init = &init; | |
79 | ||
80 | /* register the clock */ | |
81 | hw = &fixed->hw; | |
82 | ret = clk_hw_register(dev, hw); | |
83 | if (ret) { | |
84 | kfree(fixed); | |
85 | hw = ERR_PTR(ret); | |
86 | } | |
87 | ||
88 | return hw; | |
89 | } | |
90 | EXPORT_SYMBOL_GPL(clk_hw_register_fixed_rate_with_accuracy); | |
91 | ||
92 | struct clk *clk_register_fixed_rate_with_accuracy(struct device *dev, | |
93 | const char *name, const char *parent_name, unsigned long flags, | |
94 | unsigned long fixed_rate, unsigned long fixed_accuracy) | |
95 | { | |
96 | struct clk_hw *hw; | |
97 | ||
98 | hw = clk_hw_register_fixed_rate_with_accuracy(dev, name, parent_name, | |
99 | flags, fixed_rate, fixed_accuracy); | |
100 | if (IS_ERR(hw)) | |
101 | return ERR_CAST(hw); | |
102 | return hw->clk; | |
103 | } | |
104 | EXPORT_SYMBOL_GPL(clk_register_fixed_rate_with_accuracy); | |
105 | ||
106 | /** | |
107 | * clk_hw_register_fixed_rate - register fixed-rate clock with the clock | |
108 | * framework | |
109 | * @dev: device that is registering this clock | |
110 | * @name: name of this clock | |
111 | * @parent_name: name of clock's parent | |
112 | * @flags: framework-specific flags | |
113 | * @fixed_rate: non-adjustable clock rate | |
114 | */ | |
115 | struct clk_hw *clk_hw_register_fixed_rate(struct device *dev, const char *name, | |
116 | const char *parent_name, unsigned long flags, | |
117 | unsigned long fixed_rate) | |
118 | { | |
119 | return clk_hw_register_fixed_rate_with_accuracy(dev, name, parent_name, | |
120 | flags, fixed_rate, 0); | |
121 | } | |
122 | EXPORT_SYMBOL_GPL(clk_hw_register_fixed_rate); | |
123 | ||
124 | struct clk *clk_register_fixed_rate(struct device *dev, const char *name, | |
125 | const char *parent_name, unsigned long flags, | |
126 | unsigned long fixed_rate) | |
127 | { | |
128 | return clk_register_fixed_rate_with_accuracy(dev, name, parent_name, | |
129 | flags, fixed_rate, 0); | |
130 | } | |
131 | EXPORT_SYMBOL_GPL(clk_register_fixed_rate); | |
132 | ||
133 | void clk_unregister_fixed_rate(struct clk *clk) | |
134 | { | |
135 | struct clk_hw *hw; | |
136 | ||
137 | hw = __clk_get_hw(clk); | |
138 | if (!hw) | |
139 | return; | |
140 | ||
141 | clk_unregister(clk); | |
142 | kfree(to_clk_fixed_rate(hw)); | |
143 | } | |
144 | EXPORT_SYMBOL_GPL(clk_unregister_fixed_rate); | |
145 | ||
146 | void clk_hw_unregister_fixed_rate(struct clk_hw *hw) | |
147 | { | |
148 | struct clk_fixed_rate *fixed; | |
149 | ||
150 | fixed = to_clk_fixed_rate(hw); | |
151 | ||
152 | clk_hw_unregister(hw); | |
153 | kfree(fixed); | |
154 | } | |
155 | EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_rate); | |
156 | ||
157 | #ifdef CONFIG_OF | |
158 | static struct clk *_of_fixed_clk_setup(struct device_node *node) | |
159 | { | |
160 | struct clk *clk; | |
161 | const char *clk_name = node->name; | |
162 | u32 rate; | |
163 | u32 accuracy = 0; | |
164 | int ret; | |
165 | ||
166 | if (of_property_read_u32(node, "clock-frequency", &rate)) | |
167 | return ERR_PTR(-EIO); | |
168 | ||
169 | of_property_read_u32(node, "clock-accuracy", &accuracy); | |
170 | ||
171 | of_property_read_string(node, "clock-output-names", &clk_name); | |
172 | ||
173 | clk = clk_register_fixed_rate_with_accuracy(NULL, clk_name, NULL, | |
174 | 0, rate, accuracy); | |
175 | if (IS_ERR(clk)) | |
176 | return clk; | |
177 | ||
178 | ret = of_clk_add_provider(node, of_clk_src_simple_get, clk); | |
179 | if (ret) { | |
180 | clk_unregister(clk); | |
181 | return ERR_PTR(ret); | |
182 | } | |
183 | ||
184 | return clk; | |
185 | } | |
186 | ||
187 | /** | |
188 | * of_fixed_clk_setup() - Setup function for simple fixed rate clock | |
189 | */ | |
190 | void __init of_fixed_clk_setup(struct device_node *node) | |
191 | { | |
192 | _of_fixed_clk_setup(node); | |
193 | } | |
194 | CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup); | |
195 | ||
196 | static int of_fixed_clk_remove(struct platform_device *pdev) | |
197 | { | |
198 | struct clk *clk = platform_get_drvdata(pdev); | |
199 | ||
200 | of_clk_del_provider(pdev->dev.of_node); | |
201 | clk_unregister_fixed_rate(clk); | |
202 | ||
203 | return 0; | |
204 | } | |
205 | ||
206 | static int of_fixed_clk_probe(struct platform_device *pdev) | |
207 | { | |
208 | struct clk *clk; | |
209 | ||
210 | /* | |
211 | * This function is not executed when of_fixed_clk_setup | |
212 | * succeeded. | |
213 | */ | |
214 | clk = _of_fixed_clk_setup(pdev->dev.of_node); | |
215 | if (IS_ERR(clk)) | |
216 | return PTR_ERR(clk); | |
217 | ||
218 | platform_set_drvdata(pdev, clk); | |
219 | ||
220 | return 0; | |
221 | } | |
222 | ||
223 | static const struct of_device_id of_fixed_clk_ids[] = { | |
224 | { .compatible = "fixed-clock" }, | |
225 | { } | |
226 | }; | |
227 | MODULE_DEVICE_TABLE(of, of_fixed_clk_ids); | |
228 | ||
229 | static struct platform_driver of_fixed_clk_driver = { | |
230 | .driver = { | |
231 | .name = "of_fixed_clk", | |
232 | .of_match_table = of_fixed_clk_ids, | |
233 | }, | |
234 | .probe = of_fixed_clk_probe, | |
235 | .remove = of_fixed_clk_remove, | |
236 | }; | |
237 | builtin_platform_driver(of_fixed_clk_driver); | |
238 | #endif |