clk-fixed-factor.c

  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 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
 50static 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
 62static 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
 73const 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};
 79EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
 80
 81static 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
 93static struct clk_hw *
 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 */
165struct 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}
174EXPORT_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 */
189struct 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}
198EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_parent_hw);
199
200struct 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}
209EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_parent_hw);
210
211struct 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}
220EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
221
222struct 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}
231EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_fwname);
232
233struct 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}
244EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_with_accuracy_fwname);
245
246struct 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}
255EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_index);
256
257struct 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}
269EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
270
271void 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}
282EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
283
284void 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}
293EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor);
294
295struct 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}
304EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor);
305
306struct 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}
315EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_fwname);
316
317struct 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}
328EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_with_accuracy_fwname);
329
330#ifdef CONFIG_OF
331static 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 */
377void __init of_fixed_factor_clk_setup(struct device_node *node)
378{
379	_of_fixed_factor_clk_setup(node);
380}
381CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
382		of_fixed_factor_clk_setup);
383
384static 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
392static 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
409static const struct of_device_id of_fixed_factor_clk_ids[] = {
410	{ .compatible = "fixed-factor-clock" },
411	{ }
412};
413MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids);
414
415static 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};
423builtin_platform_driver(of_fixed_factor_clk_driver);
424#endif