1// SPDX-License-Identifier: GPL-2.0+
2//
3// OWL factor clock driver
4//
5// Copyright (c) 2014 Actions Semi Inc.
6// Author: David Liu <liuwei@actions-semi.com>
7//
8// Copyright (c) 2018 Linaro Ltd.
9// Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
10
11#include <linux/clk-provider.h>
12#include <linux/regmap.h>
13
14#include "owl-factor.h"
15
16static unsigned int _get_table_maxval(const struct clk_factor_table *table)
17{
18 unsigned int maxval = 0;
19 const struct clk_factor_table *clkt;
20
21 for (clkt = table; clkt->div; clkt++)
22 if (clkt->val > maxval)
23 maxval = clkt->val;
24 return maxval;
25}
26
27static int _get_table_div_mul(const struct clk_factor_table *table,
28 unsigned int val, unsigned int *mul, unsigned int *div)
29{
30 const struct clk_factor_table *clkt;
31
32 for (clkt = table; clkt->div; clkt++) {
33 if (clkt->val == val) {
34 *mul = clkt->mul;
35 *div = clkt->div;
36 return 1;
37 }
38 }
39
40 return 0;
41}
42
43static unsigned int _get_table_val(const struct clk_factor_table *table,
44 unsigned long rate, unsigned long parent_rate)
45{
46 const struct clk_factor_table *clkt;
47 int val = -1;
48 u64 calc_rate;
49
50 for (clkt = table; clkt->div; clkt++) {
51 calc_rate = parent_rate * clkt->mul;
52 do_div(calc_rate, clkt->div);
53
54 if ((unsigned long)calc_rate <= rate) {
55 val = clkt->val;
56 break;
57 }
58 }
59
60 if (val == -1)
61 val = _get_table_maxval(table);
62
63 return val;
64}
65
66static int owl_clk_val_best(const struct owl_factor_hw *factor_hw,
67 struct clk_hw *hw, unsigned long rate,
68 unsigned long *best_parent_rate)
69{
70 const struct clk_factor_table *clkt = factor_hw->table;
71 unsigned long parent_rate, try_parent_rate, best = 0, cur_rate;
72 unsigned long parent_rate_saved = *best_parent_rate;
73 int bestval = 0;
74
75 if (!rate)
76 rate = 1;
77
78 if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
79 parent_rate = *best_parent_rate;
80 bestval = _get_table_val(table: clkt, rate, parent_rate);
81 return bestval;
82 }
83
84 for (clkt = factor_hw->table; clkt->div; clkt++) {
85 try_parent_rate = rate * clkt->div / clkt->mul;
86
87 if (try_parent_rate == parent_rate_saved) {
88 pr_debug("%s: [%d %d %d] found try_parent_rate %ld\n",
89 __func__, clkt->val, clkt->mul, clkt->div,
90 try_parent_rate);
91 /*
92 * It's the most ideal case if the requested rate can be
93 * divided from parent clock without any need to change
94 * parent rate, so return the divider immediately.
95 */
96 *best_parent_rate = parent_rate_saved;
97 return clkt->val;
98 }
99
100 parent_rate = clk_hw_round_rate(hw: clk_hw_get_parent(hw),
101 rate: try_parent_rate);
102 cur_rate = DIV_ROUND_UP(parent_rate, clkt->div) * clkt->mul;
103 if (cur_rate <= rate && cur_rate > best) {
104 bestval = clkt->val;
105 best = cur_rate;
106 *best_parent_rate = parent_rate;
107 }
108 }
109
110 if (!bestval) {
111 bestval = _get_table_maxval(table: clkt);
112 *best_parent_rate = clk_hw_round_rate(
113 hw: clk_hw_get_parent(hw), rate: 1);
114 }
115
116 return bestval;
117}
118
119long owl_factor_helper_round_rate(struct owl_clk_common *common,
120 const struct owl_factor_hw *factor_hw,
121 unsigned long rate,
122 unsigned long *parent_rate)
123{
124 const struct clk_factor_table *clkt = factor_hw->table;
125 unsigned int val, mul = 0, div = 1;
126
127 val = owl_clk_val_best(factor_hw, hw: &common->hw, rate, best_parent_rate: parent_rate);
128 _get_table_div_mul(table: clkt, val, mul: &mul, div: &div);
129
130 return *parent_rate * mul / div;
131}
132
133static long owl_factor_round_rate(struct clk_hw *hw, unsigned long rate,
134 unsigned long *parent_rate)
135{
136 struct owl_factor *factor = hw_to_owl_factor(hw);
137 struct owl_factor_hw *factor_hw = &factor->factor_hw;
138
139 return owl_factor_helper_round_rate(common: &factor->common, factor_hw,
140 rate, parent_rate);
141}
142
143unsigned long owl_factor_helper_recalc_rate(struct owl_clk_common *common,
144 const struct owl_factor_hw *factor_hw,
145 unsigned long parent_rate)
146{
147 const struct clk_factor_table *clkt = factor_hw->table;
148 unsigned long long int rate;
149 u32 reg, val, mul, div;
150
151 div = 0;
152 mul = 0;
153
154 regmap_read(map: common->regmap, reg: factor_hw->reg, val: &reg);
155
156 val = reg >> factor_hw->shift;
157 val &= div_mask(factor_hw);
158
159 _get_table_div_mul(table: clkt, val, mul: &mul, div: &div);
160 if (!div) {
161 WARN(!(factor_hw->fct_flags & CLK_DIVIDER_ALLOW_ZERO),
162 "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
163 __clk_get_name(common->hw.clk));
164 return parent_rate;
165 }
166
167 rate = (unsigned long long int)parent_rate * mul;
168 do_div(rate, div);
169
170 return rate;
171}
172
173static unsigned long owl_factor_recalc_rate(struct clk_hw *hw,
174 unsigned long parent_rate)
175{
176 struct owl_factor *factor = hw_to_owl_factor(hw);
177 struct owl_factor_hw *factor_hw = &factor->factor_hw;
178 struct owl_clk_common *common = &factor->common;
179
180 return owl_factor_helper_recalc_rate(common, factor_hw, parent_rate);
181}
182
183int owl_factor_helper_set_rate(const struct owl_clk_common *common,
184 const struct owl_factor_hw *factor_hw,
185 unsigned long rate,
186 unsigned long parent_rate)
187{
188 u32 val, reg;
189
190 val = _get_table_val(table: factor_hw->table, rate, parent_rate);
191
192 if (val > div_mask(factor_hw))
193 val = div_mask(factor_hw);
194
195 regmap_read(map: common->regmap, reg: factor_hw->reg, val: &reg);
196
197 reg &= ~(div_mask(factor_hw) << factor_hw->shift);
198 reg |= val << factor_hw->shift;
199
200 regmap_write(map: common->regmap, reg: factor_hw->reg, val: reg);
201
202 return 0;
203}
204
205static int owl_factor_set_rate(struct clk_hw *hw, unsigned long rate,
206 unsigned long parent_rate)
207{
208 struct owl_factor *factor = hw_to_owl_factor(hw);
209 struct owl_factor_hw *factor_hw = &factor->factor_hw;
210 struct owl_clk_common *common = &factor->common;
211
212 return owl_factor_helper_set_rate(common, factor_hw,
213 rate, parent_rate);
214}
215
216const struct clk_ops owl_factor_ops = {
217 .round_rate = owl_factor_round_rate,
218 .recalc_rate = owl_factor_recalc_rate,
219 .set_rate = owl_factor_set_rate,
220};
221

source code of linux/drivers/clk/actions/owl-factor.c