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 
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 
33 static 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 
48 static 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 
60 const 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 };
65 EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
66 
67 static 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 
79 static 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  */
150 struct 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 }
157 EXPORT_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  */
172 struct 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 }
179 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor_parent_hw);
180 
181 struct 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 }
189 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor_parent_hw);
190 
191 struct 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 }
198 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
199 
200 struct 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 }
212 EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
213 
214 void 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 }
225 EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
226 
227 void 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 }
236 EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor);
237 
238 struct 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 }
245 EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor);
246 
247 #ifdef CONFIG_OF
248 static 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  */
293 void __init of_fixed_factor_clk_setup(struct device_node *node)
294 {
295 	_of_fixed_factor_clk_setup(node);
296 }
297 CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
298 		of_fixed_factor_clk_setup);
299 
300 static int 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 	return 0;
308 }
309 
310 static int of_fixed_factor_clk_probe(struct platform_device *pdev)
311 {
312 	struct clk_hw *clk;
313 
314 	/*
315 	 * This function is not executed when of_fixed_factor_clk_setup
316 	 * succeeded.
317 	 */
318 	clk = _of_fixed_factor_clk_setup(pdev->dev.of_node);
319 	if (IS_ERR(clk))
320 		return PTR_ERR(clk);
321 
322 	platform_set_drvdata(pdev, clk);
323 
324 	return 0;
325 }
326 
327 static const struct of_device_id of_fixed_factor_clk_ids[] = {
328 	{ .compatible = "fixed-factor-clock" },
329 	{ }
330 };
331 MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids);
332 
333 static struct platform_driver of_fixed_factor_clk_driver = {
334 	.driver = {
335 		.name = "of_fixed_factor_clk",
336 		.of_match_table = of_fixed_factor_clk_ids,
337 	},
338 	.probe = of_fixed_factor_clk_probe,
339 	.remove = of_fixed_factor_clk_remove,
340 };
341 builtin_platform_driver(of_fixed_factor_clk_driver);
342 #endif
343