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 
13 struct _ccu_nk {
14 	unsigned long	n, min_n, max_n;
15 	unsigned long	k, min_k, max_k;
16 };
17 
ccu_nk_find_best(unsigned long parent,unsigned long rate,struct _ccu_nk * nk)18 static 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 
ccu_nk_disable(struct clk_hw * hw)44 static 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 
ccu_nk_enable(struct clk_hw * hw)51 static 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 
ccu_nk_is_enabled(struct clk_hw * hw)58 static 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 
ccu_nk_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)65 static 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 
ccu_nk_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * parent_rate)93 static 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 
ccu_nk_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)116 static 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 
151 const 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