xref: /linux/drivers/clk/clk-fixed-factor.c (revision 522ba450b56fff29f868b1552bdc2965f55de7ed)
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 
clk_factor_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)22 static 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 
clk_factor_determine_rate(struct clk_hw * hw,struct clk_rate_request * req)33 static int clk_factor_determine_rate(struct clk_hw *hw,
34 				     struct clk_rate_request *req)
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 = (req->rate / fix->mult) * fix->div;
42 		req->best_parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);
43 	}
44 
45 	req->rate = (req->best_parent_rate / fix->div) * fix->mult;
46 
47 	return 0;
48 }
49 
clk_factor_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)50 static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
51 				unsigned long parent_rate)
52 {
53 	/*
54 	 * We must report success but we can do so unconditionally because
55 	 * clk_factor_determine_rate returns values that ensure this call is a
56 	 * nop.
57 	 */
58 
59 	return 0;
60 }
61 
clk_factor_recalc_accuracy(struct clk_hw * hw,unsigned long parent_accuracy)62 static unsigned long clk_factor_recalc_accuracy(struct clk_hw *hw,
63 						unsigned long parent_accuracy)
64 {
65 	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
66 
67 	if (fix->flags & CLK_FIXED_FACTOR_FIXED_ACCURACY)
68 		return fix->acc;
69 
70 	return parent_accuracy;
71 }
72 
73 const struct clk_ops clk_fixed_factor_ops = {
74 	.determine_rate = clk_factor_determine_rate,
75 	.set_rate = clk_factor_set_rate,
76 	.recalc_rate = clk_factor_recalc_rate,
77 	.recalc_accuracy = clk_factor_recalc_accuracy,
78 };
79 EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
80 
devm_clk_hw_register_fixed_factor_release(struct device * dev,void * res)81 static void devm_clk_hw_register_fixed_factor_release(struct device *dev, void *res)
82 {
83 	struct clk_fixed_factor *fix = res;
84 
85 	/*
86 	 * We can not use clk_hw_unregister_fixed_factor, since it will kfree()
87 	 * the hw, resulting in double free. Just unregister the hw and let
88 	 * devres code kfree() it.
89 	 */
90 	clk_hw_unregister(&fix->hw);
91 }
92 
93 static struct clk_hw *
__clk_hw_register_fixed_factor(struct device * dev,struct device_node * np,const char * name,const char * parent_name,const struct clk_hw * parent_hw,const struct clk_parent_data * pdata,unsigned long flags,unsigned int mult,unsigned int div,unsigned long acc,unsigned int fixflags,bool devm)94 __clk_hw_register_fixed_factor(struct device *dev, struct device_node *np,
95 		const char *name, const char *parent_name,
96 		const struct clk_hw *parent_hw, const struct clk_parent_data *pdata,
97 		unsigned long flags, unsigned int mult, unsigned int div,
98 		unsigned long acc, unsigned int fixflags, bool devm)
99 {
100 	struct clk_fixed_factor *fix;
101 	struct clk_init_data init = { };
102 	struct clk_hw *hw;
103 	int ret;
104 
105 	/* You can't use devm without a dev */
106 	if (devm && !dev)
107 		return ERR_PTR(-EINVAL);
108 
109 	if (devm)
110 		fix = devres_alloc(devm_clk_hw_register_fixed_factor_release,
111 				sizeof(*fix), GFP_KERNEL);
112 	else
113 		fix = kmalloc(sizeof(*fix), GFP_KERNEL);
114 	if (!fix)
115 		return ERR_PTR(-ENOMEM);
116 
117 	/* struct clk_fixed_factor assignments */
118 	fix->mult = mult;
119 	fix->div = div;
120 	fix->hw.init = &init;
121 	fix->acc = acc;
122 	fix->flags = fixflags;
123 
124 	init.name = name;
125 	init.ops = &clk_fixed_factor_ops;
126 	init.flags = flags;
127 	if (parent_name)
128 		init.parent_names = &parent_name;
129 	else if (parent_hw)
130 		init.parent_hws = &parent_hw;
131 	else
132 		init.parent_data = pdata;
133 	init.num_parents = 1;
134 
135 	hw = &fix->hw;
136 	if (dev)
137 		ret = clk_hw_register(dev, hw);
138 	else
139 		ret = of_clk_hw_register(np, hw);
140 	if (ret) {
141 		if (devm)
142 			devres_free(fix);
143 		else
144 			kfree(fix);
145 		hw = ERR_PTR(ret);
146 	} else if (devm)
147 		devres_add(dev, fix);
148 
149 	return hw;
150 }
151 
152 /**
153  * devm_clk_hw_register_fixed_factor_index - Register a fixed factor clock with
154  * parent from DT index
155  * @dev: device that is registering this clock
156  * @name: name of this clock
157  * @index: index of phandle in @dev 'clocks' property
158  * @flags: fixed factor flags
159  * @mult: multiplier
160  * @div: divider
161  *
162  * Return: Pointer to fixed factor clk_hw structure that was registered or
163  * an error pointer.
164  */
devm_clk_hw_register_fixed_factor_index(struct device * dev,const char * name,unsigned int index,unsigned long flags,unsigned int mult,unsigned int div)165 struct clk_hw *devm_clk_hw_register_fixed_factor_index(struct device *dev,
166 		const char *name, unsigned int index, unsigned long flags,
167 		unsigned int mult, unsigned int div)
168 {
169 	const struct clk_parent_data pdata = { .index = index };
170 
171 	return __clk_hw_register_fixed_factor(dev, NULL, name, NULL, NULL, &pdata,
172 					      flags, mult, div, 0, 0, true);
173 }
174 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_index);
175 
176 /**
177  * devm_clk_hw_register_fixed_factor_parent_hw - Register a fixed factor clock with
178  * pointer to parent clock
179  * @dev: device that is registering this clock
180  * @name: name of this clock
181  * @parent_hw: pointer to parent clk
182  * @flags: fixed factor flags
183  * @mult: multiplier
184  * @div: divider
185  *
186  * Return: Pointer to fixed factor clk_hw structure that was registered or
187  * an error pointer.
188  */
devm_clk_hw_register_fixed_factor_parent_hw(struct device * dev,const char * name,const struct clk_hw * parent_hw,unsigned long flags,unsigned int mult,unsigned int div)189 struct clk_hw *devm_clk_hw_register_fixed_factor_parent_hw(struct device *dev,
190 		const char *name, const struct clk_hw *parent_hw,
191 		unsigned long flags, unsigned int mult, unsigned int div)
192 {
193 	const struct clk_parent_data pdata = { .index = -1 };
194 
195 	return __clk_hw_register_fixed_factor(dev, NULL, name, NULL, parent_hw,
196 					      &pdata, flags, mult, div, 0, 0, true);
197 }
198 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_parent_hw);
199 
clk_hw_register_fixed_factor_parent_hw(struct device * dev,const char * name,const struct clk_hw * parent_hw,unsigned long flags,unsigned int mult,unsigned int div)200 struct clk_hw *clk_hw_register_fixed_factor_parent_hw(struct device *dev,
201 		const char *name, const struct clk_hw *parent_hw,
202 		unsigned long flags, unsigned int mult, unsigned int div)
203 {
204 	const struct clk_parent_data pdata = { .index = -1 };
205 
206 	return __clk_hw_register_fixed_factor(dev, NULL, name, NULL, parent_hw,
207 					      &pdata, flags, mult, div, 0, 0, false);
208 }
209 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_parent_hw);
210 
clk_hw_register_fixed_factor(struct device * dev,const char * name,const char * parent_name,unsigned long flags,unsigned int mult,unsigned int div)211 struct clk_hw *clk_hw_register_fixed_factor(struct device *dev,
212 		const char *name, const char *parent_name, unsigned long flags,
213 		unsigned int mult, unsigned int div)
214 {
215 	const struct clk_parent_data pdata = { .index = -1 };
216 
217 	return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, NULL,
218 					      &pdata, flags, mult, div, 0, 0, false);
219 }
220 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
221 
clk_hw_register_fixed_factor_fwname(struct device * dev,struct device_node * np,const char * name,const char * fw_name,unsigned long flags,unsigned int mult,unsigned int div)222 struct clk_hw *clk_hw_register_fixed_factor_fwname(struct device *dev,
223 		struct device_node *np, const char *name, const char *fw_name,
224 		unsigned long flags, unsigned int mult, unsigned int div)
225 {
226 	const struct clk_parent_data pdata = { .index = -1, .fw_name = fw_name };
227 
228 	return __clk_hw_register_fixed_factor(dev, np, name, NULL, NULL,
229 			&pdata, flags, mult, div, 0, 0, false);
230 }
231 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_fwname);
232 
clk_hw_register_fixed_factor_with_accuracy_fwname(struct device * dev,struct device_node * np,const char * name,const char * fw_name,unsigned long flags,unsigned int mult,unsigned int div,unsigned long acc)233 struct clk_hw *clk_hw_register_fixed_factor_with_accuracy_fwname(struct device *dev,
234 		struct device_node *np, const char *name, const char *fw_name,
235 		unsigned long flags, unsigned int mult, unsigned int div,
236 		unsigned long acc)
237 {
238 	const struct clk_parent_data pdata = { .index = -1, .fw_name = fw_name };
239 
240 	return __clk_hw_register_fixed_factor(dev, np, name, NULL, NULL,
241 			&pdata, flags, mult, div, acc,
242 			CLK_FIXED_FACTOR_FIXED_ACCURACY, false);
243 }
244 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_with_accuracy_fwname);
245 
clk_hw_register_fixed_factor_index(struct device * dev,const char * name,unsigned int index,unsigned long flags,unsigned int mult,unsigned int div)246 struct clk_hw *clk_hw_register_fixed_factor_index(struct device *dev,
247 		const char *name, unsigned int index, unsigned long flags,
248 		unsigned int mult, unsigned int div)
249 {
250 	const struct clk_parent_data pdata = { .index = index };
251 
252 	return __clk_hw_register_fixed_factor(dev, NULL, name, NULL, NULL, &pdata,
253 					      flags, mult, div, 0, 0, false);
254 }
255 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_index);
256 
clk_register_fixed_factor(struct device * dev,const char * name,const char * parent_name,unsigned long flags,unsigned int mult,unsigned int div)257 struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
258 		const char *parent_name, unsigned long flags,
259 		unsigned int mult, unsigned int div)
260 {
261 	struct clk_hw *hw;
262 
263 	hw = clk_hw_register_fixed_factor(dev, name, parent_name, flags, mult,
264 					  div);
265 	if (IS_ERR(hw))
266 		return ERR_CAST(hw);
267 	return hw->clk;
268 }
269 EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
270 
clk_unregister_fixed_factor(struct clk * clk)271 void clk_unregister_fixed_factor(struct clk *clk)
272 {
273 	struct clk_hw *hw;
274 
275 	hw = __clk_get_hw(clk);
276 	if (!hw)
277 		return;
278 
279 	clk_unregister(clk);
280 	kfree(to_clk_fixed_factor(hw));
281 }
282 EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
283 
clk_hw_unregister_fixed_factor(struct clk_hw * hw)284 void clk_hw_unregister_fixed_factor(struct clk_hw *hw)
285 {
286 	struct clk_fixed_factor *fix;
287 
288 	fix = to_clk_fixed_factor(hw);
289 
290 	clk_hw_unregister(hw);
291 	kfree(fix);
292 }
293 EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor);
294 
devm_clk_hw_register_fixed_factor(struct device * dev,const char * name,const char * parent_name,unsigned long flags,unsigned int mult,unsigned int div)295 struct clk_hw *devm_clk_hw_register_fixed_factor(struct device *dev,
296 		const char *name, const char *parent_name, unsigned long flags,
297 		unsigned int mult, unsigned int div)
298 {
299 	const struct clk_parent_data pdata = { .index = -1 };
300 
301 	return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, NULL,
302 			&pdata, flags, mult, div, 0, 0, true);
303 }
304 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor);
305 
devm_clk_hw_register_fixed_factor_fwname(struct device * dev,struct device_node * np,const char * name,const char * fw_name,unsigned long flags,unsigned int mult,unsigned int div)306 struct clk_hw *devm_clk_hw_register_fixed_factor_fwname(struct device *dev,
307 		struct device_node *np, const char *name, const char *fw_name,
308 		unsigned long flags, unsigned int mult, unsigned int div)
309 {
310 	const struct clk_parent_data pdata = { .index = -1, .fw_name = fw_name };
311 
312 	return __clk_hw_register_fixed_factor(dev, np, name, NULL, NULL,
313 			&pdata, flags, mult, div, 0, 0, true);
314 }
315 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_fwname);
316 
devm_clk_hw_register_fixed_factor_with_accuracy_fwname(struct device * dev,struct device_node * np,const char * name,const char * fw_name,unsigned long flags,unsigned int mult,unsigned int div,unsigned long acc)317 struct clk_hw *devm_clk_hw_register_fixed_factor_with_accuracy_fwname(struct device *dev,
318 		struct device_node *np, const char *name, const char *fw_name,
319 		unsigned long flags, unsigned int mult, unsigned int div,
320 		unsigned long acc)
321 {
322 	const struct clk_parent_data pdata = { .index = -1, .fw_name = fw_name };
323 
324 	return __clk_hw_register_fixed_factor(dev, np, name, NULL, NULL,
325 			&pdata, flags, mult, div, acc,
326 			CLK_FIXED_FACTOR_FIXED_ACCURACY, true);
327 }
328 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_with_accuracy_fwname);
329 
330 #ifdef CONFIG_OF
_of_fixed_factor_clk_setup(struct device_node * node)331 static struct clk_hw *_of_fixed_factor_clk_setup(struct device_node *node)
332 {
333 	struct clk_hw *hw;
334 	const char *clk_name = node->name;
335 	const struct clk_parent_data pdata = { .index = 0 };
336 	u32 div, mult;
337 	int ret;
338 
339 	if (of_property_read_u32(node, "clock-div", &div)) {
340 		pr_err("%s Fixed factor clock <%pOFn> must have a clock-div property\n",
341 			__func__, node);
342 		return ERR_PTR(-EIO);
343 	}
344 
345 	if (of_property_read_u32(node, "clock-mult", &mult)) {
346 		pr_err("%s Fixed factor clock <%pOFn> must have a clock-mult property\n",
347 			__func__, node);
348 		return ERR_PTR(-EIO);
349 	}
350 
351 	of_property_read_string(node, "clock-output-names", &clk_name);
352 
353 	hw = __clk_hw_register_fixed_factor(NULL, node, clk_name, NULL, NULL,
354 					    &pdata, 0, mult, div, 0, 0, false);
355 	if (IS_ERR(hw)) {
356 		/*
357 		 * Clear OF_POPULATED flag so that clock registration can be
358 		 * attempted again from probe function.
359 		 */
360 		of_node_clear_flag(node, OF_POPULATED);
361 		return ERR_CAST(hw);
362 	}
363 
364 	ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw);
365 	if (ret) {
366 		clk_hw_unregister_fixed_factor(hw);
367 		return ERR_PTR(ret);
368 	}
369 
370 	return hw;
371 }
372 
373 /**
374  * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
375  * @node:	device node for the clock
376  */
of_fixed_factor_clk_setup(struct device_node * node)377 void __init of_fixed_factor_clk_setup(struct device_node *node)
378 {
379 	_of_fixed_factor_clk_setup(node);
380 }
381 CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
382 		of_fixed_factor_clk_setup);
383 
of_fixed_factor_clk_remove(struct platform_device * pdev)384 static void of_fixed_factor_clk_remove(struct platform_device *pdev)
385 {
386 	struct clk_hw *clk = platform_get_drvdata(pdev);
387 
388 	of_clk_del_provider(pdev->dev.of_node);
389 	clk_hw_unregister_fixed_factor(clk);
390 }
391 
of_fixed_factor_clk_probe(struct platform_device * pdev)392 static int of_fixed_factor_clk_probe(struct platform_device *pdev)
393 {
394 	struct clk_hw *clk;
395 
396 	/*
397 	 * This function is not executed when of_fixed_factor_clk_setup
398 	 * succeeded.
399 	 */
400 	clk = _of_fixed_factor_clk_setup(pdev->dev.of_node);
401 	if (IS_ERR(clk))
402 		return PTR_ERR(clk);
403 
404 	platform_set_drvdata(pdev, clk);
405 
406 	return 0;
407 }
408 
409 static const struct of_device_id of_fixed_factor_clk_ids[] = {
410 	{ .compatible = "fixed-factor-clock" },
411 	{ }
412 };
413 MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids);
414 
415 static struct platform_driver of_fixed_factor_clk_driver = {
416 	.driver = {
417 		.name = "of_fixed_factor_clk",
418 		.of_match_table = of_fixed_factor_clk_ids,
419 	},
420 	.probe = of_fixed_factor_clk_probe,
421 	.remove = of_fixed_factor_clk_remove,
422 };
423 builtin_platform_driver(of_fixed_factor_clk_driver);
424 #endif
425