1/*
2 * mmp factor clock operation source file
3 *
4 * Copyright (C) 2012 Marvell
5 * Chao Xie <xiechao.mail@gmail.com>
6 *
7 * This file is licensed under the terms of the GNU General Public
8 * License version 2. This program is licensed "as is" without any
9 * warranty of any kind, whether express or implied.
10 */
11
12#include <linux/clk-provider.h>
13#include <linux/slab.h>
14#include <linux/io.h>
15#include <linux/err.h>
16
17#include "clk.h"
18/*
19 * It is M/N clock
20 *
21 * Fout from synthesizer can be given from two equations:
22 * numerator/denominator = Fin / (Fout * factor)
23 */
24
25#define to_clk_factor(hw) container_of(hw, struct mmp_clk_factor, hw)
26
27static long clk_factor_round_rate(struct clk_hw *hw, unsigned long drate,
28		unsigned long *prate)
29{
30	struct mmp_clk_factor *factor = to_clk_factor(hw);
31	u64 rate = 0, prev_rate;
32	int i;
33
34	for (i = 0; i < factor->ftbl_cnt; i++) {
35		prev_rate = rate;
36		rate = *prate;
37		rate *= factor->ftbl[i].den;
38		do_div(rate, factor->ftbl[i].num * factor->masks->factor);
39
40		if (rate > drate)
41			break;
42	}
43	if ((i == 0) || (i == factor->ftbl_cnt)) {
44		return rate;
45	} else {
46		if ((drate - prev_rate) > (rate - drate))
47			return rate;
48		else
49			return prev_rate;
50	}
51}
52
53static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
54		unsigned long parent_rate)
55{
56	struct mmp_clk_factor *factor = to_clk_factor(hw);
57	struct mmp_clk_factor_masks *masks = factor->masks;
58	unsigned int val, num, den;
59	u64 rate;
60
61	val = readl_relaxed(factor->base);
62
63	/* calculate numerator */
64	num = (val >> masks->num_shift) & masks->num_mask;
65
66	/* calculate denominator */
67	den = (val >> masks->den_shift) & masks->den_mask;
68
69	if (!den)
70		return 0;
71
72	rate = parent_rate;
73	rate *= den;
74	do_div(rate, num * factor->masks->factor);
75
76	return rate;
77}
78
79/* Configures new clock rate*/
80static int clk_factor_set_rate(struct clk_hw *hw, unsigned long drate,
81				unsigned long prate)
82{
83	struct mmp_clk_factor *factor = to_clk_factor(hw);
84	struct mmp_clk_factor_masks *masks = factor->masks;
85	int i;
86	unsigned long val;
87	unsigned long flags = 0;
88	u64 rate = 0;
89
90	for (i = 0; i < factor->ftbl_cnt; i++) {
91		rate = prate;
92		rate *= factor->ftbl[i].den;
93		do_div(rate, factor->ftbl[i].num * factor->masks->factor);
94
95		if (rate > drate)
96			break;
97	}
98	if (i > 0)
99		i--;
100
101	if (factor->lock)
102		spin_lock_irqsave(factor->lock, flags);
103
104	val = readl_relaxed(factor->base);
105
106	val &= ~(masks->num_mask << masks->num_shift);
107	val |= (factor->ftbl[i].num & masks->num_mask) << masks->num_shift;
108
109	val &= ~(masks->den_mask << masks->den_shift);
110	val |= (factor->ftbl[i].den & masks->den_mask) << masks->den_shift;
111
112	writel_relaxed(val, factor->base);
113
114	if (factor->lock)
115		spin_unlock_irqrestore(factor->lock, flags);
116
117	return 0;
118}
119
120static int clk_factor_init(struct clk_hw *hw)
121{
122	struct mmp_clk_factor *factor = to_clk_factor(hw);
123	struct mmp_clk_factor_masks *masks = factor->masks;
124	u32 val, num, den;
125	int i;
126	unsigned long flags = 0;
127
128	if (factor->lock)
129		spin_lock_irqsave(factor->lock, flags);
130
131	val = readl(factor->base);
132
133	/* calculate numerator */
134	num = (val >> masks->num_shift) & masks->num_mask;
135
136	/* calculate denominator */
137	den = (val >> masks->den_shift) & masks->den_mask;
138
139	for (i = 0; i < factor->ftbl_cnt; i++)
140		if (den == factor->ftbl[i].den && num == factor->ftbl[i].num)
141			break;
142
143	if (i >= factor->ftbl_cnt) {
144		val &= ~(masks->num_mask << masks->num_shift);
145		val |= (factor->ftbl[0].num & masks->num_mask) <<
146			masks->num_shift;
147
148		val &= ~(masks->den_mask << masks->den_shift);
149		val |= (factor->ftbl[0].den & masks->den_mask) <<
150			masks->den_shift;
151	}
152
153	if (!(val & masks->enable_mask) || i >= factor->ftbl_cnt) {
154		val |= masks->enable_mask;
155		writel(val, factor->base);
156	}
157
158	if (factor->lock)
159		spin_unlock_irqrestore(factor->lock, flags);
160
161	return 0;
162}
163
164static const struct clk_ops clk_factor_ops = {
165	.recalc_rate = clk_factor_recalc_rate,
166	.round_rate = clk_factor_round_rate,
167	.set_rate = clk_factor_set_rate,
168	.init = clk_factor_init,
169};
170
171struct clk *mmp_clk_register_factor(const char *name, const char *parent_name,
172		unsigned long flags, void __iomem *base,
173		struct mmp_clk_factor_masks *masks,
174		struct mmp_clk_factor_tbl *ftbl,
175		unsigned int ftbl_cnt, spinlock_t *lock)
176{
177	struct mmp_clk_factor *factor;
178	struct clk_init_data init;
179	struct clk *clk;
180
181	if (!masks) {
182		pr_err("%s: must pass a clk_factor_mask\n", __func__);
183		return ERR_PTR(-EINVAL);
184	}
185
186	factor = kzalloc(sizeof(*factor), GFP_KERNEL);
187	if (!factor)
188		return ERR_PTR(-ENOMEM);
189
190	/* struct clk_aux assignments */
191	factor->base = base;
192	factor->masks = masks;
193	factor->ftbl = ftbl;
194	factor->ftbl_cnt = ftbl_cnt;
195	factor->hw.init = &init;
196	factor->lock = lock;
197
198	init.name = name;
199	init.ops = &clk_factor_ops;
200	init.flags = flags;
201	init.parent_names = &parent_name;
202	init.num_parents = 1;
203
204	clk = clk_register(NULL, &factor->hw);
205	if (IS_ERR_OR_NULL(clk))
206		kfree(factor);
207
208	return clk;
209}
210