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 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 
109 struct 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 }
116 EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
117 
118 struct 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 }
130 EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
131 
132 void 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 }
143 EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
144 
145 void 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 }
154 EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor);
155 
156 #ifdef CONFIG_OF
157 static const struct of_device_id set_rate_parent_matches[] = {
158 	{ .compatible = "allwinner,sun4i-a10-pll3-2x-clk" },
159 	{ /* Sentinel */ },
160 };
161 
162 static 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  */
210 void __init of_fixed_factor_clk_setup(struct device_node *node)
211 {
212 	_of_fixed_factor_clk_setup(node);
213 }
214 CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
215 		of_fixed_factor_clk_setup);
216 
217 static 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 
227 static 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 
244 static const struct of_device_id of_fixed_factor_clk_ids[] = {
245 	{ .compatible = "fixed-factor-clock" },
246 	{ }
247 };
248 MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids);
249 
250 static 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 };
258 builtin_platform_driver(of_fixed_factor_clk_driver);
259 #endif
260