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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
4 */
5#include <linux/module.h>
6#include <linux/clk-provider.h>
7#include <linux/slab.h>
8#include <linux/err.h>
9#include <linux/of.h>
10#include <linux/platform_device.h>
11
12/*
13 * DOC: basic fixed multiplier and divider clock that cannot gate
14 *
15 * Traits of this clock:
16 * prepare - clk_prepare only ensures that parents are prepared
17 * enable - clk_enable only ensures that parents are enabled
18 * rate - rate is fixed. clk->rate = parent->rate / div * mult
19 * parent - fixed parent. No clk_set_parent support
20 */
21
22static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
23 unsigned long parent_rate)
24{
25 struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
26 unsigned long long int rate;
27
28 rate = (unsigned long long int)parent_rate * fix->mult;
29 do_div(rate, fix->div);
30 return (unsigned long)rate;
31}
32
33static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
34 unsigned long *prate)
35{
36 struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
37
38 if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
39 unsigned long best_parent;
40
41 best_parent = (rate / fix->mult) * fix->div;
42 *prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);
43 }
44
45 return (*prate / fix->div) * fix->mult;
46}
47
48static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
49 unsigned long parent_rate)
50{
51 /*
52 * We must report success but we can do so unconditionally because
53 * clk_factor_round_rate returns values that ensure this call is a
54 * nop.
55 */
56
57 return 0;
58}
59
60const struct clk_ops clk_fixed_factor_ops = {
61 .round_rate = clk_factor_round_rate,
62 .set_rate = clk_factor_set_rate,
63 .recalc_rate = clk_factor_recalc_rate,
64};
65EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
66
67static void devm_clk_hw_register_fixed_factor_release(struct device *dev, void *res)
68{
69 struct clk_fixed_factor *fix = res;
70
71 /*
72 * We can not use clk_hw_unregister_fixed_factor, since it will kfree()
73 * the hw, resulting in double free. Just unregister the hw and let
74 * devres code kfree() it.
75 */
76 clk_hw_unregister(&fix->hw);
77}
78
79static struct clk_hw *
80__clk_hw_register_fixed_factor(struct device *dev, struct device_node *np,
81 const char *name, const char *parent_name,
82 const struct clk_hw *parent_hw, int index,
83 unsigned long flags, unsigned int mult, unsigned int div,
84 bool devm)
85{
86 struct clk_fixed_factor *fix;
87 struct clk_init_data init = { };
88 struct clk_parent_data pdata = { .index = index };
89 struct clk_hw *hw;
90 int ret;
91
92 /* You can't use devm without a dev */
93 if (devm && !dev)
94 return ERR_PTR(-EINVAL);
95
96 if (devm)
97 fix = devres_alloc(devm_clk_hw_register_fixed_factor_release,
98 sizeof(*fix), GFP_KERNEL);
99 else
100 fix = kmalloc(sizeof(*fix), GFP_KERNEL);
101 if (!fix)
102 return ERR_PTR(-ENOMEM);
103
104 /* struct clk_fixed_factor assignments */
105 fix->mult = mult;
106 fix->div = div;
107 fix->hw.init = &init;
108
109 init.name = name;
110 init.ops = &clk_fixed_factor_ops;
111 init.flags = flags;
112 if (parent_name)
113 init.parent_names = &parent_name;
114 else if (parent_hw)
115 init.parent_hws = &parent_hw;
116 else
117 init.parent_data = &pdata;
118 init.num_parents = 1;
119
120 hw = &fix->hw;
121 if (dev)
122 ret = clk_hw_register(dev, hw);
123 else
124 ret = of_clk_hw_register(np, hw);
125 if (ret) {
126 if (devm)
127 devres_free(fix);
128 else
129 kfree(fix);
130 hw = ERR_PTR(ret);
131 } else if (devm)
132 devres_add(dev, fix);
133
134 return hw;
135}
136
137/**
138 * devm_clk_hw_register_fixed_factor_index - Register a fixed factor clock with
139 * parent from DT index
140 * @dev: device that is registering this clock
141 * @name: name of this clock
142 * @index: index of phandle in @dev 'clocks' property
143 * @flags: fixed factor flags
144 * @mult: multiplier
145 * @div: divider
146 *
147 * Return: Pointer to fixed factor clk_hw structure that was registered or
148 * an error pointer.
149 */
150struct clk_hw *devm_clk_hw_register_fixed_factor_index(struct device *dev,
151 const char *name, unsigned int index, unsigned long flags,
152 unsigned int mult, unsigned int div)
153{
154 return __clk_hw_register_fixed_factor(dev, NULL, name, NULL, NULL, index,
155 flags, mult, div, true);
156}
157EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_index);
158
159/**
160 * devm_clk_hw_register_fixed_factor_parent_hw - Register a fixed factor clock with
161 * pointer to parent clock
162 * @dev: device that is registering this clock
163 * @name: name of this clock
164 * @parent_hw: pointer to parent clk
165 * @flags: fixed factor flags
166 * @mult: multiplier
167 * @div: divider
168 *
169 * Return: Pointer to fixed factor clk_hw structure that was registered or
170 * an error pointer.
171 */
172struct clk_hw *devm_clk_hw_register_fixed_factor_parent_hw(struct device *dev,
173 const char *name, const struct clk_hw *parent_hw,
174 unsigned long flags, unsigned int mult, unsigned int div)
175{
176 return __clk_hw_register_fixed_factor(dev, NULL, name, NULL, parent_hw,
177 -1, flags, mult, div, true);
178}
179EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_parent_hw);
180
181struct clk_hw *clk_hw_register_fixed_factor_parent_hw(struct device *dev,
182 const char *name, const struct clk_hw *parent_hw,
183 unsigned long flags, unsigned int mult, unsigned int div)
184{
185 return __clk_hw_register_fixed_factor(dev, NULL, name, NULL,
186 parent_hw, -1, flags, mult, div,
187 false);
188}
189EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_parent_hw);
190
191struct clk_hw *clk_hw_register_fixed_factor(struct device *dev,
192 const char *name, const char *parent_name, unsigned long flags,
193 unsigned int mult, unsigned int div)
194{
195 return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, NULL, -1,
196 flags, mult, div, false);
197}
198EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
199
200struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
201 const char *parent_name, unsigned long flags,
202 unsigned int mult, unsigned int div)
203{
204 struct clk_hw *hw;
205
206 hw = clk_hw_register_fixed_factor(dev, name, parent_name, flags, mult,
207 div);
208 if (IS_ERR(hw))
209 return ERR_CAST(hw);
210 return hw->clk;
211}
212EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
213
214void clk_unregister_fixed_factor(struct clk *clk)
215{
216 struct clk_hw *hw;
217
218 hw = __clk_get_hw(clk);
219 if (!hw)
220 return;
221
222 clk_unregister(clk);
223 kfree(to_clk_fixed_factor(hw));
224}
225EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
226
227void clk_hw_unregister_fixed_factor(struct clk_hw *hw)
228{
229 struct clk_fixed_factor *fix;
230
231 fix = to_clk_fixed_factor(hw);
232
233 clk_hw_unregister(hw);
234 kfree(fix);
235}
236EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor);
237
238struct clk_hw *devm_clk_hw_register_fixed_factor(struct device *dev,
239 const char *name, const char *parent_name, unsigned long flags,
240 unsigned int mult, unsigned int div)
241{
242 return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, NULL, -1,
243 flags, mult, div, true);
244}
245EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor);
246
247#ifdef CONFIG_OF
248static struct clk_hw *_of_fixed_factor_clk_setup(struct device_node *node)
249{
250 struct clk_hw *hw;
251 const char *clk_name = node->name;
252 u32 div, mult;
253 int ret;
254
255 if (of_property_read_u32(node, "clock-div", &div)) {
256 pr_err("%s Fixed factor clock <%pOFn> must have a clock-div property\n",
257 __func__, node);
258 return ERR_PTR(-EIO);
259 }
260
261 if (of_property_read_u32(node, "clock-mult", &mult)) {
262 pr_err("%s Fixed factor clock <%pOFn> must have a clock-mult property\n",
263 __func__, node);
264 return ERR_PTR(-EIO);
265 }
266
267 of_property_read_string(node, "clock-output-names", &clk_name);
268
269 hw = __clk_hw_register_fixed_factor(NULL, node, clk_name, NULL, NULL, 0,
270 0, mult, div, false);
271 if (IS_ERR(hw)) {
272 /*
273 * Clear OF_POPULATED flag so that clock registration can be
274 * attempted again from probe function.
275 */
276 of_node_clear_flag(node, OF_POPULATED);
277 return ERR_CAST(hw);
278 }
279
280 ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw);
281 if (ret) {
282 clk_hw_unregister_fixed_factor(hw);
283 return ERR_PTR(ret);
284 }
285
286 return hw;
287}
288
289/**
290 * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
291 * @node: device node for the clock
292 */
293void __init of_fixed_factor_clk_setup(struct device_node *node)
294{
295 _of_fixed_factor_clk_setup(node);
296}
297CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
298 of_fixed_factor_clk_setup);
299
300static void of_fixed_factor_clk_remove(struct platform_device *pdev)
301{
302 struct clk_hw *clk = platform_get_drvdata(pdev);
303
304 of_clk_del_provider(pdev->dev.of_node);
305 clk_hw_unregister_fixed_factor(clk);
306}
307
308static int of_fixed_factor_clk_probe(struct platform_device *pdev)
309{
310 struct clk_hw *clk;
311
312 /*
313 * This function is not executed when of_fixed_factor_clk_setup
314 * succeeded.
315 */
316 clk = _of_fixed_factor_clk_setup(pdev->dev.of_node);
317 if (IS_ERR(clk))
318 return PTR_ERR(clk);
319
320 platform_set_drvdata(pdev, clk);
321
322 return 0;
323}
324
325static const struct of_device_id of_fixed_factor_clk_ids[] = {
326 { .compatible = "fixed-factor-clock" },
327 { }
328};
329MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids);
330
331static struct platform_driver of_fixed_factor_clk_driver = {
332 .driver = {
333 .name = "of_fixed_factor_clk",
334 .of_match_table = of_fixed_factor_clk_ids,
335 },
336 .probe = of_fixed_factor_clk_probe,
337 .remove_new = of_fixed_factor_clk_remove,
338};
339builtin_platform_driver(of_fixed_factor_clk_driver);
340#endif