1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * mmp factor clock operation source file
  4 *
  5 * Copyright (C) 2012 Marvell
  6 * Chao Xie <xiechao.mail@gmail.com>
  7 */
  8
  9#include <linux/clk-provider.h>
 10#include <linux/slab.h>
 11#include <linux/io.h>
 12#include <linux/err.h>
 13
 14#include "clk.h"
 15/*
 16 * It is M/N clock
 17 *
 18 * Fout from synthesizer can be given from two equations:
 19 * numerator/denominator = Fin / (Fout * factor)
 20 */
 21
 22#define to_clk_factor(hw) container_of(hw, struct mmp_clk_factor, hw)
 23
 24static long clk_factor_round_rate(struct clk_hw *hw, unsigned long drate,
 25		unsigned long *prate)
 26{
 27	struct mmp_clk_factor *factor = to_clk_factor(hw);
 28	u64 rate = 0, prev_rate;
 29	int i;
 30
 31	for (i = 0; i < factor->ftbl_cnt; i++) {
 32		prev_rate = rate;
 33		rate = *prate;
 34		rate *= factor->ftbl[i].den;
 35		do_div(rate, factor->ftbl[i].num * factor->masks->factor);
 36
 37		if (rate > drate)
 38			break;
 39	}
 40	if ((i == 0) || (i == factor->ftbl_cnt)) {
 41		return rate;
 42	} else {
 43		if ((drate - prev_rate) > (rate - drate))
 44			return rate;
 45		else
 46			return prev_rate;
 47	}
 48}
 49
 50static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
 51		unsigned long parent_rate)
 52{
 53	struct mmp_clk_factor *factor = to_clk_factor(hw);
 54	struct mmp_clk_factor_masks *masks = factor->masks;
 55	unsigned int val, num, den;
 56	u64 rate;
 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	rate = parent_rate;
 70	rate *= den;
 71	do_div(rate, num * factor->masks->factor);
 72
 73	return rate;
 74}
 75
 76/* Configures new clock rate*/
 77static int clk_factor_set_rate(struct clk_hw *hw, unsigned long drate,
 78				unsigned long prate)
 79{
 80	struct mmp_clk_factor *factor = to_clk_factor(hw);
 81	struct mmp_clk_factor_masks *masks = factor->masks;
 82	int i;
 83	unsigned long val;
 84	unsigned long flags = 0;
 85	u64 rate = 0;
 86
 87	for (i = 0; i < factor->ftbl_cnt; i++) {
 88		rate = prate;
 89		rate *= factor->ftbl[i].den;
 90		do_div(rate, factor->ftbl[i].num * factor->masks->factor);
 91
 92		if (rate > drate)
 93			break;
 94	}
 95	if (i > 0)
 96		i--;
 97
 98	if (factor->lock)
 99		spin_lock_irqsave(factor->lock, flags);
100
101	val = readl_relaxed(factor->base);
102
103	val &= ~(masks->num_mask << masks->num_shift);
104	val |= (factor->ftbl[i].num & masks->num_mask) << masks->num_shift;
105
106	val &= ~(masks->den_mask << masks->den_shift);
107	val |= (factor->ftbl[i].den & masks->den_mask) << masks->den_shift;
108
109	writel_relaxed(val, factor->base);
110
111	if (factor->lock)
112		spin_unlock_irqrestore(factor->lock, flags);
113
114	return 0;
115}
116
117static int clk_factor_init(struct clk_hw *hw)
118{
119	struct mmp_clk_factor *factor = to_clk_factor(hw);
120	struct mmp_clk_factor_masks *masks = factor->masks;
121	u32 val, num, den;
122	int i;
123	unsigned long flags = 0;
124
125	if (factor->lock)
126		spin_lock_irqsave(factor->lock, flags);
127
128	val = readl(factor->base);
129
130	/* calculate numerator */
131	num = (val >> masks->num_shift) & masks->num_mask;
132
133	/* calculate denominator */
134	den = (val >> masks->den_shift) & masks->den_mask;
135
136	for (i = 0; i < factor->ftbl_cnt; i++)
137		if (den == factor->ftbl[i].den && num == factor->ftbl[i].num)
138			break;
139
140	if (i >= factor->ftbl_cnt) {
141		val &= ~(masks->num_mask << masks->num_shift);
142		val |= (factor->ftbl[0].num & masks->num_mask) <<
143			masks->num_shift;
144
145		val &= ~(masks->den_mask << masks->den_shift);
146		val |= (factor->ftbl[0].den & masks->den_mask) <<
147			masks->den_shift;
148	}
149
150	if (!(val & masks->enable_mask) || i >= factor->ftbl_cnt) {
151		val |= masks->enable_mask;
152		writel(val, factor->base);
153	}
154
155	if (factor->lock)
156		spin_unlock_irqrestore(factor->lock, flags);
157
158	return 0;
159}
160
161static const struct clk_ops clk_factor_ops = {
162	.recalc_rate = clk_factor_recalc_rate,
163	.round_rate = clk_factor_round_rate,
164	.set_rate = clk_factor_set_rate,
165	.init = clk_factor_init,
166};
167
168struct clk *mmp_clk_register_factor(const char *name, const char *parent_name,
169		unsigned long flags, void __iomem *base,
170		struct mmp_clk_factor_masks *masks,
171		struct mmp_clk_factor_tbl *ftbl,
172		unsigned int ftbl_cnt, spinlock_t *lock)
173{
174	struct mmp_clk_factor *factor;
175	struct clk_init_data init;
176	struct clk *clk;
177
178	if (!masks) {
179		pr_err("%s: must pass a clk_factor_mask\n", __func__);
180		return ERR_PTR(-EINVAL);
181	}
182
183	factor = kzalloc(sizeof(*factor), GFP_KERNEL);
184	if (!factor)
185		return ERR_PTR(-ENOMEM);
186
187	/* struct clk_aux assignments */
188	factor->base = base;
189	factor->masks = masks;
190	factor->ftbl = ftbl;
191	factor->ftbl_cnt = ftbl_cnt;
192	factor->hw.init = &init;
193	factor->lock = lock;
194
195	init.name = name;
196	init.ops = &clk_factor_ops;
197	init.flags = flags;
198	init.parent_names = &parent_name;
199	init.num_parents = 1;
200
201	clk = clk_register(NULL, &factor->hw);
202	if (IS_ERR_OR_NULL(clk))
203		kfree(factor);
204
205	return clk;
206}