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 unsigned long 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 	return best_rate;
44 }
45 
ccu_nk_disable(struct clk_hw * hw)46 static void ccu_nk_disable(struct clk_hw *hw)
47 {
48 	struct ccu_nk *nk = hw_to_ccu_nk(hw);
49 
50 	return ccu_gate_helper_disable(&nk->common, nk->enable);
51 }
52 
ccu_nk_enable(struct clk_hw * hw)53 static int ccu_nk_enable(struct clk_hw *hw)
54 {
55 	struct ccu_nk *nk = hw_to_ccu_nk(hw);
56 
57 	return ccu_gate_helper_enable(&nk->common, nk->enable);
58 }
59 
ccu_nk_is_enabled(struct clk_hw * hw)60 static int ccu_nk_is_enabled(struct clk_hw *hw)
61 {
62 	struct ccu_nk *nk = hw_to_ccu_nk(hw);
63 
64 	return ccu_gate_helper_is_enabled(&nk->common, nk->enable);
65 }
66 
ccu_nk_recalc_rate(struct clk_hw * hw,unsigned long parent_rate)67 static unsigned long ccu_nk_recalc_rate(struct clk_hw *hw,
68 					unsigned long parent_rate)
69 {
70 	struct ccu_nk *nk = hw_to_ccu_nk(hw);
71 	unsigned long rate, n, k;
72 	u32 reg;
73 
74 	reg = readl(nk->common.base + nk->common.reg);
75 
76 	n = reg >> nk->n.shift;
77 	n &= (1 << nk->n.width) - 1;
78 	n += nk->n.offset;
79 	if (!n)
80 		n++;
81 
82 	k = reg >> nk->k.shift;
83 	k &= (1 << nk->k.width) - 1;
84 	k += nk->k.offset;
85 	if (!k)
86 		k++;
87 
88 	rate = parent_rate * n * k;
89 	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
90 		rate /= nk->fixed_post_div;
91 
92 	return rate;
93 }
94 
ccu_nk_round_rate(struct clk_hw * hw,unsigned long rate,unsigned long * parent_rate)95 static long ccu_nk_round_rate(struct clk_hw *hw, unsigned long rate,
96 			      unsigned long *parent_rate)
97 {
98 	struct ccu_nk *nk = hw_to_ccu_nk(hw);
99 	struct _ccu_nk _nk;
100 
101 	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
102 		rate *= nk->fixed_post_div;
103 
104 	_nk.min_n = nk->n.min ?: 1;
105 	_nk.max_n = nk->n.max ?: 1 << nk->n.width;
106 	_nk.min_k = nk->k.min ?: 1;
107 	_nk.max_k = nk->k.max ?: 1 << nk->k.width;
108 
109 	rate = ccu_nk_find_best(*parent_rate, rate, &_nk);
110 
111 	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
112 		rate = rate / nk->fixed_post_div;
113 
114 	return rate;
115 }
116 
ccu_nk_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)117 static int ccu_nk_set_rate(struct clk_hw *hw, unsigned long rate,
118 			   unsigned long parent_rate)
119 {
120 	struct ccu_nk *nk = hw_to_ccu_nk(hw);
121 	unsigned long flags;
122 	struct _ccu_nk _nk;
123 	u32 reg;
124 
125 	if (nk->common.features & CCU_FEATURE_FIXED_POSTDIV)
126 		rate = rate * nk->fixed_post_div;
127 
128 	_nk.min_n = nk->n.min ?: 1;
129 	_nk.max_n = nk->n.max ?: 1 << nk->n.width;
130 	_nk.min_k = nk->k.min ?: 1;
131 	_nk.max_k = nk->k.max ?: 1 << nk->k.width;
132 
133 	ccu_nk_find_best(parent_rate, rate, &_nk);
134 
135 	spin_lock_irqsave(nk->common.lock, flags);
136 
137 	reg = readl(nk->common.base + nk->common.reg);
138 	reg &= ~GENMASK(nk->n.width + nk->n.shift - 1, nk->n.shift);
139 	reg &= ~GENMASK(nk->k.width + nk->k.shift - 1, nk->k.shift);
140 
141 	reg |= (_nk.k - nk->k.offset) << nk->k.shift;
142 	reg |= (_nk.n - nk->n.offset) << nk->n.shift;
143 	writel(reg, nk->common.base + nk->common.reg);
144 
145 	spin_unlock_irqrestore(nk->common.lock, flags);
146 
147 	ccu_helper_wait_for_lock(&nk->common, nk->lock);
148 
149 	return 0;
150 }
151 
152 const struct clk_ops ccu_nk_ops = {
153 	.disable	= ccu_nk_disable,
154 	.enable		= ccu_nk_enable,
155 	.is_enabled	= ccu_nk_is_enabled,
156 
157 	.recalc_rate	= ccu_nk_recalc_rate,
158 	.round_rate	= ccu_nk_round_rate,
159 	.set_rate	= ccu_nk_set_rate,
160 };
161 EXPORT_SYMBOL_NS_GPL(ccu_nk_ops, SUNXI_CCU);
162