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 struct clk_hw *
 68__clk_hw_register_fixed_factor(struct device *dev, struct device_node *np,
 69		const char *name, const char *parent_name, int index,
 70		unsigned long flags, unsigned int mult, unsigned int div)
 71{
 72	struct clk_fixed_factor *fix;
 73	struct clk_init_data init = { };
 74	struct clk_parent_data pdata = { .index = index };
 75	struct clk_hw *hw;
 76	int ret;
 77
 78	fix = kmalloc(sizeof(*fix), GFP_KERNEL);
 79	if (!fix)
 80		return ERR_PTR(-ENOMEM);
 81
 82	/* struct clk_fixed_factor assignments */
 83	fix->mult = mult;
 84	fix->div = div;
 85	fix->hw.init = &init;
 86
 87	init.name = name;
 88	init.ops = &clk_fixed_factor_ops;
 89	init.flags = flags;
 90	if (parent_name)
 91		init.parent_names = &parent_name;
 92	else
 93		init.parent_data = &pdata;
 94	init.num_parents = 1;
 95
 96	hw = &fix->hw;
 97	if (dev)
 98		ret = clk_hw_register(dev, hw);
 99	else
100		ret = of_clk_hw_register(np, hw);
101	if (ret) {
102		kfree(fix);
103		hw = ERR_PTR(ret);
104	}
105
106	return hw;
107}
108
109struct clk_hw *clk_hw_register_fixed_factor(struct device *dev,
110		const char *name, const char *parent_name, unsigned long flags,
111		unsigned int mult, unsigned int div)
112{
113	return __clk_hw_register_fixed_factor(dev, NULL, name, parent_name, -1,
114					      flags, mult, div);
115}
116EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
117
118struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
119		const char *parent_name, unsigned long flags,
120		unsigned int mult, unsigned int div)
121{
122	struct clk_hw *hw;
123
124	hw = clk_hw_register_fixed_factor(dev, name, parent_name, flags, mult,
125					  div);
126	if (IS_ERR(hw))
127		return ERR_CAST(hw);
128	return hw->clk;
129}
130EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
131
132void clk_unregister_fixed_factor(struct clk *clk)
133{
134	struct clk_hw *hw;
135
136	hw = __clk_get_hw(clk);
137	if (!hw)
138		return;
139
140	clk_unregister(clk);
141	kfree(to_clk_fixed_factor(hw));
142}
143EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
144
145void clk_hw_unregister_fixed_factor(struct clk_hw *hw)
146{
147	struct clk_fixed_factor *fix;
148
149	fix = to_clk_fixed_factor(hw);
150
151	clk_hw_unregister(hw);
152	kfree(fix);
153}
154EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor);
155
156#ifdef CONFIG_OF
157static const struct of_device_id set_rate_parent_matches[] = {
158	{ .compatible = "allwinner,sun4i-a10-pll3-2x-clk" },
159	{ /* Sentinel */ },
160};
161
162static struct clk_hw *_of_fixed_factor_clk_setup(struct device_node *node)
163{
164	struct clk_hw *hw;
165	const char *clk_name = node->name;
166	unsigned long flags = 0;
167	u32 div, mult;
168	int ret;
169
170	if (of_property_read_u32(node, "clock-div", &div)) {
171		pr_err("%s Fixed factor clock <%pOFn> must have a clock-div property\n",
172			__func__, node);
173		return ERR_PTR(-EIO);
174	}
175
176	if (of_property_read_u32(node, "clock-mult", &mult)) {
177		pr_err("%s Fixed factor clock <%pOFn> must have a clock-mult property\n",
178			__func__, node);
179		return ERR_PTR(-EIO);
180	}
181
182	of_property_read_string(node, "clock-output-names", &clk_name);
183
184	if (of_match_node(set_rate_parent_matches, node))
185		flags |= CLK_SET_RATE_PARENT;
186
187	hw = __clk_hw_register_fixed_factor(NULL, node, clk_name, NULL, 0,
188					    flags, mult, div);
189	if (IS_ERR(hw)) {
190		/*
191		 * Clear OF_POPULATED flag so that clock registration can be
192		 * attempted again from probe function.
193		 */
194		of_node_clear_flag(node, OF_POPULATED);
195		return ERR_CAST(hw);
196	}
197
198	ret = of_clk_add_hw_provider(node, of_clk_hw_simple_get, hw);
199	if (ret) {
200		clk_hw_unregister_fixed_factor(hw);
201		return ERR_PTR(ret);
202	}
203
204	return hw;
205}
206
207/**
208 * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
209 */
210void __init of_fixed_factor_clk_setup(struct device_node *node)
211{
212	_of_fixed_factor_clk_setup(node);
213}
214CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
215		of_fixed_factor_clk_setup);
216
217static int of_fixed_factor_clk_remove(struct platform_device *pdev)
218{
219	struct clk_hw *clk = platform_get_drvdata(pdev);
220
221	of_clk_del_provider(pdev->dev.of_node);
222	clk_hw_unregister_fixed_factor(clk);
223
224	return 0;
225}
226
227static int of_fixed_factor_clk_probe(struct platform_device *pdev)
228{
229	struct clk_hw *clk;
230
231	/*
232	 * This function is not executed when of_fixed_factor_clk_setup
233	 * succeeded.
234	 */
235	clk = _of_fixed_factor_clk_setup(pdev->dev.of_node);
236	if (IS_ERR(clk))
237		return PTR_ERR(clk);
238
239	platform_set_drvdata(pdev, clk);
240
241	return 0;
242}
243
244static const struct of_device_id of_fixed_factor_clk_ids[] = {
245	{ .compatible = "fixed-factor-clock" },
246	{ }
247};
248MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids);
249
250static struct platform_driver of_fixed_factor_clk_driver = {
251	.driver = {
252		.name = "of_fixed_factor_clk",
253		.of_match_table = of_fixed_factor_clk_ids,
254	},
255	.probe = of_fixed_factor_clk_probe,
256	.remove = of_fixed_factor_clk_remove,
257};
258builtin_platform_driver(of_fixed_factor_clk_driver);
259#endif