1/*
  2 * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
  3 *
  4 * This program is free software; you can redistribute it and/or modify
  5 * it under the terms of the GNU General Public License version 2 as
  6 * published by the Free Software Foundation.
  7 *
  8 * Standard functionality for the common clock API.
  9 */
 10#include <linux/module.h>
 11#include <linux/clk-provider.h>
 12#include <linux/slab.h>
 13#include <linux/err.h>
 14#include <linux/of.h>
 15
 16/*
 17 * DOC: basic fixed multiplier and divider clock that cannot gate
 18 *
 19 * Traits of this clock:
 20 * prepare - clk_prepare only ensures that parents are prepared
 21 * enable - clk_enable only ensures that parents are enabled
 22 * rate - rate is fixed.  clk->rate = parent->rate / div * mult
 23 * parent - fixed parent.  No clk_set_parent support
 24 */
 25
 26static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
 27		unsigned long parent_rate)
 28{
 29	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
 30	unsigned long long int rate;
 31
 32	rate = (unsigned long long int)parent_rate * fix->mult;
 33	do_div(rate, fix->div);
 34	return (unsigned long)rate;
 35}
 36
 37static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
 38				unsigned long *prate)
 39{
 40	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);
 41
 42	if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
 43		unsigned long best_parent;
 44
 45		best_parent = (rate / fix->mult) * fix->div;
 46		*prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);
 47	}
 48
 49	return (*prate / fix->div) * fix->mult;
 50}
 51
 52static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
 53				unsigned long parent_rate)
 54{
 55	/*
 56	 * We must report success but we can do so unconditionally because
 57	 * clk_factor_round_rate returns values that ensure this call is a
 58	 * nop.
 59	 */
 60
 61	return 0;
 62}
 63
 64const struct clk_ops clk_fixed_factor_ops = {
 65	.round_rate = clk_factor_round_rate,
 66	.set_rate = clk_factor_set_rate,
 67	.recalc_rate = clk_factor_recalc_rate,
 68};
 69EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);
 70
 71struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
 72		const char *parent_name, unsigned long flags,
 73		unsigned int mult, unsigned int div)
 74{
 75	struct clk_fixed_factor *fix;
 76	struct clk_init_data init;
 77	struct clk *clk;
 78
 79	fix = kmalloc(sizeof(*fix), GFP_KERNEL);
 80	if (!fix)
 81		return ERR_PTR(-ENOMEM);
 82
 83	/* struct clk_fixed_factor assignments */
 84	fix->mult = mult;
 85	fix->div = div;
 86	fix->hw.init = &init;
 87
 88	init.name = name;
 89	init.ops = &clk_fixed_factor_ops;
 90	init.flags = flags | CLK_IS_BASIC;
 91	init.parent_names = &parent_name;
 92	init.num_parents = 1;
 93
 94	clk = clk_register(dev, &fix->hw);
 95
 96	if (IS_ERR(clk))
 97		kfree(fix);
 98
 99	return clk;
100}
101EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
102
103void clk_unregister_fixed_factor(struct clk *clk)
104{
105	struct clk_hw *hw;
106
107	hw = __clk_get_hw(clk);
108	if (!hw)
109		return;
110
111	clk_unregister(clk);
112	kfree(to_clk_fixed_factor(hw));
113}
114EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);
115
116#ifdef CONFIG_OF
117/**
118 * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
119 */
120void __init of_fixed_factor_clk_setup(struct device_node *node)
121{
122	struct clk *clk;
123	const char *clk_name = node->name;
124	const char *parent_name;
125	u32 div, mult;
126
127	if (of_property_read_u32(node, "clock-div", &div)) {
128		pr_err("%s Fixed factor clock <%s> must have a clock-div property\n",
129			__func__, node->name);
130		return;
131	}
132
133	if (of_property_read_u32(node, "clock-mult", &mult)) {
134		pr_err("%s Fixed factor clock <%s> must have a clock-mult property\n",
135			__func__, node->name);
136		return;
137	}
138
139	of_property_read_string(node, "clock-output-names", &clk_name);
140	parent_name = of_clk_get_parent_name(node, 0);
141
142	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
143					mult, div);
144	if (!IS_ERR(clk))
145		of_clk_add_provider(node, of_clk_src_simple_get, clk);
146}
147EXPORT_SYMBOL_GPL(of_fixed_factor_clk_setup);
148CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
149		of_fixed_factor_clk_setup);
150#endif