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	unsigned long rate = 0, prev_rate;
32	int i;
33
34	for (i = 0; i < factor->ftbl_cnt; i++) {
35		prev_rate = rate;
36		rate = (((*prate / 10000) * factor->ftbl[i].den) /
37			(factor->ftbl[i].num * factor->masks->factor)) * 10000;
38		if (rate > drate)
39			break;
40	}
41	if ((i == 0) || (i == factor->ftbl_cnt)) {
42		return rate;
43	} else {
44		if ((drate - prev_rate) > (rate - drate))
45			return rate;
46		else
47			return prev_rate;
48	}
49}
50
51static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
52		unsigned long parent_rate)
53{
54	struct mmp_clk_factor *factor = to_clk_factor(hw);
55	struct mmp_clk_factor_masks *masks = factor->masks;
56	unsigned int val, num, den;
57
58	val = readl_relaxed(factor->base);
59
60	/* calculate numerator */
61	num = (val >> masks->num_shift) & masks->num_mask;
62
63	/* calculate denominator */
64	den = (val >> masks->den_shift) & masks->den_mask;
65
66	if (!den)
67		return 0;
68
69	return (((parent_rate / 10000)  * den) /
70			(num * factor->masks->factor)) * 10000;
71}
72
73/* Configures new clock rate*/
74static int clk_factor_set_rate(struct clk_hw *hw, unsigned long drate,
75				unsigned long prate)
76{
77	struct mmp_clk_factor *factor = to_clk_factor(hw);
78	struct mmp_clk_factor_masks *masks = factor->masks;
79	int i;
80	unsigned long val;
81	unsigned long prev_rate, rate = 0;
82	unsigned long flags = 0;
83
84	for (i = 0; i < factor->ftbl_cnt; i++) {
85		prev_rate = rate;
86		rate = (((prate / 10000) * factor->ftbl[i].den) /
87			(factor->ftbl[i].num * factor->masks->factor)) * 10000;
88		if (rate > drate)
89			break;
90	}
91	if (i > 0)
92		i--;
93
94	if (factor->lock)
95		spin_lock_irqsave(factor->lock, flags);
96
97	val = readl_relaxed(factor->base);
98
99	val &= ~(masks->num_mask << masks->num_shift);
100	val |= (factor->ftbl[i].num & masks->num_mask) << masks->num_shift;
101
102	val &= ~(masks->den_mask << masks->den_shift);
103	val |= (factor->ftbl[i].den & masks->den_mask) << masks->den_shift;
104
105	writel_relaxed(val, factor->base);
106
107	if (factor->lock)
108		spin_unlock_irqrestore(factor->lock, flags);
109
110	return 0;
111}
112
113static void clk_factor_init(struct clk_hw *hw)
114{
115	struct mmp_clk_factor *factor = to_clk_factor(hw);
116	struct mmp_clk_factor_masks *masks = factor->masks;
117	u32 val, num, den;
118	int i;
119	unsigned long flags = 0;
120
121	if (factor->lock)
122		spin_lock_irqsave(factor->lock, flags);
123
124	val = readl(factor->base);
125
126	/* calculate numerator */
127	num = (val >> masks->num_shift) & masks->num_mask;
128
129	/* calculate denominator */
130	den = (val >> masks->den_shift) & masks->den_mask;
131
132	for (i = 0; i < factor->ftbl_cnt; i++)
133		if (den == factor->ftbl[i].den && num == factor->ftbl[i].num)
134			break;
135
136	if (i >= factor->ftbl_cnt) {
137		val &= ~(masks->num_mask << masks->num_shift);
138		val |= (factor->ftbl[0].num & masks->num_mask) <<
139			masks->num_shift;
140
141		val &= ~(masks->den_mask << masks->den_shift);
142		val |= (factor->ftbl[0].den & masks->den_mask) <<
143			masks->den_shift;
144
145		writel(val, factor->base);
146	}
147
148	if (factor->lock)
149		spin_unlock_irqrestore(factor->lock, flags);
150}
151
152static struct clk_ops clk_factor_ops = {
153	.recalc_rate = clk_factor_recalc_rate,
154	.round_rate = clk_factor_round_rate,
155	.set_rate = clk_factor_set_rate,
156	.init = clk_factor_init,
157};
158
159struct clk *mmp_clk_register_factor(const char *name, const char *parent_name,
160		unsigned long flags, void __iomem *base,
161		struct mmp_clk_factor_masks *masks,
162		struct mmp_clk_factor_tbl *ftbl,
163		unsigned int ftbl_cnt, spinlock_t *lock)
164{
165	struct mmp_clk_factor *factor;
166	struct clk_init_data init;
167	struct clk *clk;
168
169	if (!masks) {
170		pr_err("%s: must pass a clk_factor_mask\n", __func__);
171		return ERR_PTR(-EINVAL);
172	}
173
174	factor = kzalloc(sizeof(*factor), GFP_KERNEL);
175	if (!factor) {
176		pr_err("%s: could not allocate factor  clk\n", __func__);
177		return ERR_PTR(-ENOMEM);
178	}
179
180	/* struct clk_aux assignments */
181	factor->base = base;
182	factor->masks = masks;
183	factor->ftbl = ftbl;
184	factor->ftbl_cnt = ftbl_cnt;
185	factor->hw.init = &init;
186	factor->lock = lock;
187
188	init.name = name;
189	init.ops = &clk_factor_ops;
190	init.flags = flags;
191	init.parent_names = &parent_name;
192	init.num_parents = 1;
193
194	clk = clk_register(NULL, &factor->hw);
195	if (IS_ERR_OR_NULL(clk))
196		kfree(factor);
197
198	return clk;
199}
200