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 const 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		return ERR_PTR(-ENOMEM);
177
178	/* struct clk_aux assignments */
179	factor->base = base;
180	factor->masks = masks;
181	factor->ftbl = ftbl;
182	factor->ftbl_cnt = ftbl_cnt;
183	factor->hw.init = &init;
184	factor->lock = lock;
185
186	init.name = name;
187	init.ops = &clk_factor_ops;
188	init.flags = flags;
189	init.parent_names = &parent_name;
190	init.num_parents = 1;
191
192	clk = clk_register(NULL, &factor->hw);
193	if (IS_ERR_OR_NULL(clk))
194		kfree(factor);
195
196	return clk;
197}