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, int index,
 82		unsigned long flags, unsigned int mult, unsigned int div,
 83		bool devm)
 84{
 85	struct clk_fixed_factor *fix;
 86	struct clk_init_data init = { };
 87	struct clk_parent_data pdata = { .index = index };
 88	struct clk_hw *hw;
 89	int ret;
 90
 91	/* You can't use devm without a dev */
 92	if (devm && !dev)
 93		return ERR_PTR(-EINVAL);
 94
 95	if (devm)
 96		fix = devres_alloc(devm_clk_hw_register_fixed_factor_release,
 97				sizeof(*fix), GFP_KERNEL);
 98	else
 99		fix = kmalloc(sizeof(*fix), GFP_KERNEL);
100	if (!fix)
101		return ERR_PTR(-ENOMEM);
102
103	/* struct clk_fixed_factor assignments */
104	fix->mult = mult;
105	fix->div = div;
106	fix->hw.init = &init;
107
108	init.name = name;
109	init.ops = &clk_fixed_factor_ops;
110	init.flags = flags;
111	if (parent_name)
112		init.parent_names = &parent_name;
113	else
114		init.parent_data = &pdata;
115	init.num_parents = 1;
116
117	hw = &fix->hw;
118	if (dev)
119		ret = clk_hw_register(dev, hw);
120	else
121		ret = of_clk_hw_register(np, hw);
122	if (ret) {
123		if (devm)
124			devres_free(fix);
125		else
126			kfree(fix);
127		hw = ERR_PTR(ret);
128	} else if (devm)
129		devres_add(dev, fix);
130
131	return hw;
132}
133
134struct clk_hw *clk_hw_register_fixed_factor(struct device *dev,
135		const char *name, const char *parent_name, unsigned long flags,
136		unsigned int mult, unsigned int div)
137{
138	return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, -1,
139					      flags, mult, div, false);
140}
141EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
142
143struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
144		const char *parent_name, unsigned long flags,
145		unsigned int mult, unsigned int div)
146{
147	struct clk_hw *hw;
148
149	hw = clk_hw_register_fixed_factor(dev, name, parent_name, flags, mult,
150					  div);
151	if (IS_ERR(hw))
152		return ERR_CAST(hw);
153	return hw->clk;
154}
155EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
156
157void clk_unregister_fixed_factor(struct clk *clk)
158{
159	struct clk_hw *hw;
160
161	hw = __clk_get_hw(clk);
162	if (!hw)
163		return;
164
165	clk_unregister(clk);
166	kfree(to_clk_fixed_factor(hw));
167}
168EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
169
170void clk_hw_unregister_fixed_factor(struct clk_hw *hw)
171{
172	struct clk_fixed_factor *fix;
173
174	fix = to_clk_fixed_factor(hw);
175
176	clk_hw_unregister(hw);
177	kfree(fix);
178}
179EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor);
180
181struct clk_hw *devm_clk_hw_register_fixed_factor(struct device *dev,
182		const char *name, const char *parent_name, unsigned long flags,
183		unsigned int mult, unsigned int div)
184{
185	return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, -1,
186			flags, mult, div, true);
187}
188EXPORT_SYMBOL_GPL(devm_clk_hw_register_fixed_factor);
189
190#ifdef CONFIG_OF
191static const struct of_device_id set_rate_parent_matches[] = {
192	{ .compatible = "allwinner,sun4i-a10-pll3-2x-clk" },
193	{ /* Sentinel */ },
194};
195
196static struct clk_hw *_of_fixed_factor_clk_setup(struct device_node *node)
197{
198	struct clk_hw *hw;
199	const char *clk_name = node->name;
200	unsigned long flags = 0;
201	u32 div, mult;
202	int ret;
203
204	if (of_property_read_u32(node, "clock-div", &div)) {
205		pr_err("%s Fixed factor clock <%pOFn> must have a clock-div property\n",
206			__func__, node);
207		return ERR_PTR(-EIO);
208	}
209
210	if (of_property_read_u32(node, "clock-mult", &mult)) {
211		pr_err("%s Fixed factor clock <%pOFn> must have a clock-mult property\n",
212			__func__, node);
213		return ERR_PTR(-EIO);
214	}
215
216	of_property_read_string(node, "clock-output-names", &clk_name);
217
218	if (of_match_node(set_rate_parent_matches, node))
219		flags |= CLK_SET_RATE_PARENT;
220
221	hw = __clk_hw_register_fixed_factor(NULL, node, clk_name, NULL, 0,
222					    flags, mult, div, false);
223	if (IS_ERR(hw)) {
224		/*
225		 * Clear OF_POPULATED flag so that clock registration can be
226		 * attempted again from probe function.
227		 */
228		of_node_clear_flag(node, OF_POPULATED);
229		return ERR_CAST(hw);
230	}
231
232	ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw);
233	if (ret) {
234		clk_hw_unregister_fixed_factor(hw);
235		return ERR_PTR(ret);
236	}
237
238	return hw;
239}
240
241/**
242 * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
243 * @node:	device node for the clock
244 */
245void __init of_fixed_factor_clk_setup(struct device_node *node)
246{
247	_of_fixed_factor_clk_setup(node);
248}
249CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
250		of_fixed_factor_clk_setup);
251
252static int of_fixed_factor_clk_remove(struct platform_device *pdev)
253{
254	struct clk_hw *clk = platform_get_drvdata(pdev);
255
256	of_clk_del_provider(pdev->dev.of_node);
257	clk_hw_unregister_fixed_factor(clk);
258
259	return 0;
260}
261
262static int of_fixed_factor_clk_probe(struct platform_device *pdev)
263{
264	struct clk_hw *clk;
265
266	/*
267	 * This function is not executed when of_fixed_factor_clk_setup
268	 * succeeded.
269	 */
270	clk = _of_fixed_factor_clk_setup(pdev->dev.of_node);
271	if (IS_ERR(clk))
272		return PTR_ERR(clk);
273
274	platform_set_drvdata(pdev, clk);
275
276	return 0;
277}
278
279static const struct of_device_id of_fixed_factor_clk_ids[] = {
280	{ .compatible = "fixed-factor-clock" },
281	{ }
282};
283MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids);
284
285static struct platform_driver of_fixed_factor_clk_driver = {
286	.driver = {
287		.name = "of_fixed_factor_clk",
288		.of_match_table = of_fixed_factor_clk_ids,
289	},
290	.probe = of_fixed_factor_clk_probe,
291	.remove = of_fixed_factor_clk_remove,
292};
293builtin_platform_driver(of_fixed_factor_clk_driver);
294#endif