1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C) 2016 Maxime Ripard
4 * Maxime Ripard <maxime.ripard@free-electrons.com>
5 */
6
7#include <linux/clk-provider.h>
8#include <linux/io.h>
9
10#include "ccu_gate.h"
11#include "ccu_nk.h"
12
13struct _ccu_nk {
14	unsigned long	n, min_n, max_n;
15	unsigned long	k, min_k, max_k;
16};
17
18static void ccu_nk_find_best(unsigned long parent, unsigned long rate,
19			     struct _ccu_nk *nk)
20{
21	unsigned long best_rate = 0;
22	unsigned int best_k = 0, best_n = 0;
23	unsigned int _k, _n;
24
25	for (_k = nk->min_k; _k <= nk->max_k; _k++) {
26		for (_n = nk->min_n; _n <= nk->max_n; _n++) {
27			unsigned long tmp_rate = parent * _n * _k;
28
29			if (tmp_rate > rate)
30				continue;
31
32			if ((rate - tmp_rate) < (rate - best_rate)) {
33				best_rate = tmp_rate;
34				best_k = _k;
35				best_n = _n;
36			}
37		}
38	}
39
40	nk->k = best_k;
41	nk->n = best_n;
42}
43
44static void ccu_nk_disable(struct clk_hw *hw)
45{
46	struct ccu_nk *nk = hw_to_ccu_nk(hw);
47
48	return ccu_gate_helper_disable(&nk->common, nk->enable);
49}
50
51static int ccu_nk_enable(struct clk_hw *hw)
52{
53	struct ccu_nk *nk = hw_to_ccu_nk(hw);
54
55	return ccu_gate_helper_enable(&nk->common, nk->enable);
56}
57
58static int ccu_nk_is_enabled(struct clk_hw *hw)
59{
60	struct ccu_nk *nk = hw_to_ccu_nk(hw);
61
62	return ccu_gate_helper_is_enabled(&nk->common, nk->enable);
63}
64
65static unsigned long ccu_nk_recalc_rate(struct clk_hw *hw,
66					unsigned long parent_rate)
67{
68	struct ccu_nk *nk = hw_to_ccu_nk(hw);
69	unsigned long rate, n, k;
70	u32 reg;
71
72	reg = readl(nk->common.base + nk->common.reg);
73
74	n = reg >> nk->n.shift;
75	n &= (1 << nk->n.width) - 1;
76	n += nk->n.offset;
77	if (!n)
78		n++;
79
80	k = reg >> nk->k.shift;
81	k &= (1 << nk->k.width) - 1;
82	k += nk->k.offset;
83	if (!k)
84		k++;
85
86	rate = parent_rate * n * k;
87	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
88		rate /= nk->fixed_post_div;
89
90	return rate;
91}
92
93static long ccu_nk_round_rate(struct clk_hw *hw, unsigned long rate,
94			      unsigned long *parent_rate)
95{
96	struct ccu_nk *nk = hw_to_ccu_nk(hw);
97	struct _ccu_nk _nk;
98
99	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
100		rate *= nk->fixed_post_div;
101
102	_nk.min_n = nk->n.min ?: 1;
103	_nk.max_n = nk->n.max ?: 1 << nk->n.width;
104	_nk.min_k = nk->k.min ?: 1;
105	_nk.max_k = nk->k.max ?: 1 << nk->k.width;
106
107	ccu_nk_find_best(*parent_rate, rate, &_nk);
108	rate = *parent_rate * _nk.n * _nk.k;
109
110	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
111		rate = rate / nk->fixed_post_div;
112
113	return rate;
114}
115
116static int ccu_nk_set_rate(struct clk_hw *hw, unsigned long rate,
117			   unsigned long parent_rate)
118{
119	struct ccu_nk *nk = hw_to_ccu_nk(hw);
120	unsigned long flags;
121	struct _ccu_nk _nk;
122	u32 reg;
123
124	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
125		rate = rate * nk->fixed_post_div;
126
127	_nk.min_n = nk->n.min ?: 1;
128	_nk.max_n = nk->n.max ?: 1 << nk->n.width;
129	_nk.min_k = nk->k.min ?: 1;
130	_nk.max_k = nk->k.max ?: 1 << nk->k.width;
131
132	ccu_nk_find_best(parent_rate, rate, &_nk);
133
134	spin_lock_irqsave(nk->common.lock, flags);
135
136	reg = readl(nk->common.base + nk->common.reg);
137	reg &= ~GENMASK(nk->n.width + nk->n.shift - 1, nk->n.shift);
138	reg &= ~GENMASK(nk->k.width + nk->k.shift - 1, nk->k.shift);
139
140	reg |= (_nk.k - nk->k.offset) << nk->k.shift;
141	reg |= (_nk.n - nk->n.offset) << nk->n.shift;
142	writel(reg, nk->common.base + nk->common.reg);
143
144	spin_unlock_irqrestore(nk->common.lock, flags);
145
146	ccu_helper_wait_for_lock(&nk->common, nk->lock);
147
148	return 0;
149}
150
151const struct clk_ops ccu_nk_ops = {
152	.disable	= ccu_nk_disable,
153	.enable		= ccu_nk_enable,
154	.is_enabled	= ccu_nk_is_enabled,
155
156	.recalc_rate	= ccu_nk_recalc_rate,
157	.round_rate	= ccu_nk_round_rate,
158	.set_rate	= ccu_nk_set_rate,
159};
160