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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2010-2011 Canonical Ltd <[email protected]>
4 * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <[email protected]>
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#define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw)
28
29static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw,
30 unsigned long parent_rate)
31{
32 return to_clk_fixed_rate(hw)->fixed_rate;
33}
34
35static unsigned long clk_fixed_rate_recalc_accuracy(struct clk_hw *hw,
36 unsigned long parent_accuracy)
37{
38 struct clk_fixed_rate *fixed = to_clk_fixed_rate(hw);
39
40 if (fixed->flags & CLK_FIXED_RATE_PARENT_ACCURACY)
41 return parent_accuracy;
42
43 return fixed->fixed_accuracy;
44}
45
46const struct clk_ops clk_fixed_rate_ops = {
47 .recalc_rate = clk_fixed_rate_recalc_rate,
48 .recalc_accuracy = clk_fixed_rate_recalc_accuracy,
49};
50EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);
51
52static void devm_clk_hw_register_fixed_rate_release(struct device *dev, void *res)
53{
54 struct clk_fixed_rate *fix = res;
55
56 /*
57 * We can not use clk_hw_unregister_fixed_rate, since it will kfree()
58 * the hw, resulting in double free. Just unregister the hw and let
59 * devres code kfree() it.
60 */
61 clk_hw_unregister(&fix->hw);
62}
63
64struct clk_hw *__clk_hw_register_fixed_rate(struct device *dev,
65 struct device_node *np, const char *name,
66 const char *parent_name, const struct clk_hw *parent_hw,
67 const struct clk_parent_data *parent_data, unsigned long flags,
68 unsigned long fixed_rate, unsigned long fixed_accuracy,
69 unsigned long clk_fixed_flags, bool devm)
70{
71 struct clk_fixed_rate *fixed;
72 struct clk_hw *hw;
73 struct clk_init_data init = {};
74 int ret = -EINVAL;
75
76 /* allocate fixed-rate clock */
77 if (devm)
78 fixed = devres_alloc(devm_clk_hw_register_fixed_rate_release,
79 sizeof(*fixed), GFP_KERNEL);
80 else
81 fixed = kzalloc_obj(*fixed);
82 if (!fixed)
83 return ERR_PTR(-ENOMEM);
84
85 init.name = name;
86 init.ops = &clk_fixed_rate_ops;
87 init.flags = flags;
88 init.parent_names = parent_name ? &parent_name : NULL;
89 init.parent_hws = parent_hw ? &parent_hw : NULL;
90 init.parent_data = parent_data;
91 if (parent_name || parent_hw || parent_data)
92 init.num_parents = 1;
93 else
94 init.num_parents = 0;
95
96 /* struct clk_fixed_rate assignments */
97 fixed->flags = clk_fixed_flags;
98 fixed->fixed_rate = fixed_rate;
99 fixed->fixed_accuracy = fixed_accuracy;
100 fixed->hw.init = &init;
101
102 /* register the clock */
103 hw = &fixed->hw;
104 if (dev || !np)
105 ret = clk_hw_register(dev, hw);
106 else
107 ret = of_clk_hw_register(np, hw);
108 if (ret) {
109 if (devm)
110 devres_free(fixed);
111 else
112 kfree(fixed);
113 hw = ERR_PTR(ret);
114 } else if (devm)
115 devres_add(dev, fixed);
116
117 return hw;
118}
119EXPORT_SYMBOL_GPL(__clk_hw_register_fixed_rate);
120
121struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
122 const char *parent_name, unsigned long flags,
123 unsigned long fixed_rate)
124{
125 struct clk_hw *hw;
126
127 hw = clk_hw_register_fixed_rate_with_accuracy(dev, name, parent_name,
128 flags, fixed_rate, 0);
129 if (IS_ERR(hw))
130 return ERR_CAST(hw);
131 return hw->clk;
132}
133EXPORT_SYMBOL_GPL(clk_register_fixed_rate);
134
135void clk_unregister_fixed_rate(struct clk *clk)
136{
137 struct clk_hw *hw;
138
139 hw = __clk_get_hw(clk);
140 if (!hw)
141 return;
142
143 clk_unregister(clk);
144 kfree(to_clk_fixed_rate(hw));
145}
146EXPORT_SYMBOL_GPL(clk_unregister_fixed_rate);
147
148void clk_hw_unregister_fixed_rate(struct clk_hw *hw)
149{
150 struct clk_fixed_rate *fixed;
151
152 fixed = to_clk_fixed_rate(hw);
153
154 clk_hw_unregister(hw);
155 kfree(fixed);
156}
157EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_rate);
158
159#ifdef CONFIG_OF
160static struct clk_hw *_of_fixed_clk_setup(struct device_node *node)
161{
162 struct clk_hw *hw;
163 const char *clk_name = node->name;
164 u32 rate;
165 u32 accuracy = 0;
166 int ret;
167
168 if (of_property_read_u32(node, "clock-frequency", &rate))
169 return ERR_PTR(-EIO);
170
171 of_property_read_u32(node, "clock-accuracy", &accuracy);
172
173 of_property_read_string(node, "clock-output-names", &clk_name);
174
175 hw = clk_hw_register_fixed_rate_with_accuracy(NULL, clk_name, NULL,
176 0, rate, accuracy);
177 if (IS_ERR(hw))
178 return hw;
179
180 ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw);
181 if (ret) {
182 clk_hw_unregister_fixed_rate(hw);
183 return ERR_PTR(ret);
184 }
185
186 return hw;
187}
188
189/**
190 * of_fixed_clk_setup() - Setup function for simple fixed rate clock
191 * @node: device node for the clock
192 */
193void __init of_fixed_clk_setup(struct device_node *node)
194{
195 _of_fixed_clk_setup(node);
196}
197CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup);
198
199static void of_fixed_clk_remove(struct platform_device *pdev)
200{
201 struct clk_hw *hw = platform_get_drvdata(pdev);
202
203 of_clk_del_provider(pdev->dev.of_node);
204 clk_hw_unregister_fixed_rate(hw);
205}
206
207static int of_fixed_clk_probe(struct platform_device *pdev)
208{
209 struct clk_hw *hw;
210
211 /*
212 * This function is not executed when of_fixed_clk_setup
213 * succeeded.
214 */
215 hw = _of_fixed_clk_setup(pdev->dev.of_node);
216 if (IS_ERR(hw))
217 return PTR_ERR(hw);
218
219 platform_set_drvdata(pdev, hw);
220
221 return 0;
222}
223
224static const struct of_device_id of_fixed_clk_ids[] = {
225 { .compatible = "fixed-clock" },
226 { }
227};
228
229static 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};
237builtin_platform_driver(of_fixed_clk_driver);
238#endif