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 rate = 0;
 82	unsigned long flags = 0;
 83
 84	for (i = 0; i < factor->ftbl_cnt; i++) {
 85		rate = (((prate / 10000) * factor->ftbl[i].den) /
 86			(factor->ftbl[i].num * factor->masks->factor)) * 10000;
 87		if (rate > drate)
 88			break;
 89	}
 90	if (i > 0)
 91		i--;
 92
 93	if (factor->lock)
 94		spin_lock_irqsave(factor->lock, flags);
 95
 96	val = readl_relaxed(factor->base);
 97
 98	val &= ~(masks->num_mask << masks->num_shift);
 99	val |= (factor->ftbl[i].num & masks->num_mask) << masks->num_shift;
100
101	val &= ~(masks->den_mask << masks->den_shift);
102	val |= (factor->ftbl[i].den & masks->den_mask) << masks->den_shift;
103
104	writel_relaxed(val, factor->base);
105
106	if (factor->lock)
107		spin_unlock_irqrestore(factor->lock, flags);
108
109	return 0;
110}
111
112static void clk_factor_init(struct clk_hw *hw)
113{
114	struct mmp_clk_factor *factor = to_clk_factor(hw);
115	struct mmp_clk_factor_masks *masks = factor->masks;
116	u32 val, num, den;
117	int i;
118	unsigned long flags = 0;
119
120	if (factor->lock)
121		spin_lock_irqsave(factor->lock, flags);
122
123	val = readl(factor->base);
124
125	/* calculate numerator */
126	num = (val >> masks->num_shift) & masks->num_mask;
127
128	/* calculate denominator */
129	den = (val >> masks->den_shift) & masks->den_mask;
130
131	for (i = 0; i < factor->ftbl_cnt; i++)
132		if (den == factor->ftbl[i].den && num == factor->ftbl[i].num)
133			break;
134
135	if (i >= factor->ftbl_cnt) {
136		val &= ~(masks->num_mask << masks->num_shift);
137		val |= (factor->ftbl[0].num & masks->num_mask) <<
138			masks->num_shift;
139
140		val &= ~(masks->den_mask << masks->den_shift);
141		val |= (factor->ftbl[0].den & masks->den_mask) <<
142			masks->den_shift;
143
144		writel(val, factor->base);
145	}
146
147	if (factor->lock)
148		spin_unlock_irqrestore(factor->lock, flags);
149}
150
151static const struct clk_ops clk_factor_ops = {
152	.recalc_rate = clk_factor_recalc_rate,
153	.round_rate = clk_factor_round_rate,
154	.set_rate = clk_factor_set_rate,
155	.init = clk_factor_init,
156};
157
158struct clk *mmp_clk_register_factor(const char *name, const char *parent_name,
159		unsigned long flags, void __iomem *base,
160		struct mmp_clk_factor_masks *masks,
161		struct mmp_clk_factor_tbl *ftbl,
162		unsigned int ftbl_cnt, spinlock_t *lock)
163{
164	struct mmp_clk_factor *factor;
165	struct clk_init_data init;
166	struct clk *clk;
167
168	if (!masks) {
169		pr_err("%s: must pass a clk_factor_mask\n", __func__);
170		return ERR_PTR(-EINVAL);
171	}
172
173	factor = kzalloc(sizeof(*factor), GFP_KERNEL);
174	if (!factor)
175		return ERR_PTR(-ENOMEM);
176
177	/* struct clk_aux assignments */
178	factor->base = base;
179	factor->masks = masks;
180	factor->ftbl = ftbl;
181	factor->ftbl_cnt = ftbl_cnt;
182	factor->hw.init = &init;
183	factor->lock = lock;
184
185	init.name = name;
186	init.ops = &clk_factor_ops;
187	init.flags = flags;
188	init.parent_names = &parent_name;
189	init.num_parents = 1;
190
191	clk = clk_register(NULL, &factor->hw);
192	if (IS_ERR_OR_NULL(clk))
193		kfree(factor);
194
195	return clk;
196}