1 // SPDX-License-Identifier: GPL-2.0+
3 // OWL factor clock driver
5 // Copyright (c) 2014 Actions Semi Inc.
6 // Author: David Liu <liuwei@actions-semi.com>
8 // Copyright (c) 2018 Linaro Ltd.
9 // Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
11 #include <linux/clk-provider.h>
12 #include <linux/regmap.h>
13 #include <linux/slab.h>
15 #include "owl-factor.h"
17 static unsigned int _get_table_maxval(const struct clk_factor_table *table)
19 unsigned int maxval = 0;
20 const struct clk_factor_table *clkt;
22 for (clkt = table; clkt->div; clkt++)
23 if (clkt->val > maxval)
28 static int _get_table_div_mul(const struct clk_factor_table *table,
29 unsigned int val, unsigned int *mul, unsigned int *div)
31 const struct clk_factor_table *clkt;
33 for (clkt = table; clkt->div; clkt++) {
34 if (clkt->val == val) {
44 static unsigned int _get_table_val(const struct clk_factor_table *table,
45 unsigned long rate, unsigned long parent_rate)
47 const struct clk_factor_table *clkt;
51 for (clkt = table; clkt->div; clkt++) {
52 calc_rate = parent_rate * clkt->mul;
53 do_div(calc_rate, clkt->div);
55 if ((unsigned long)calc_rate <= rate) {
62 val = _get_table_maxval(table);
67 static int clk_val_best(struct clk_hw *hw, unsigned long rate,
68 unsigned long *best_parent_rate)
70 struct owl_factor *factor = hw_to_owl_factor(hw);
71 struct owl_factor_hw *factor_hw = &factor->factor_hw;
72 const struct clk_factor_table *clkt = factor_hw->table;
73 unsigned long parent_rate, try_parent_rate, best = 0, cur_rate;
74 unsigned long parent_rate_saved = *best_parent_rate;
80 if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
81 parent_rate = *best_parent_rate;
82 bestval = _get_table_val(clkt, rate, parent_rate);
86 for (clkt = factor_hw->table; clkt->div; clkt++) {
87 try_parent_rate = rate * clkt->div / clkt->mul;
89 if (try_parent_rate == parent_rate_saved) {
90 pr_debug("%s: [%d %d %d] found try_parent_rate %ld\n",
91 __func__, clkt->val, clkt->mul, clkt->div,
94 * It's the most ideal case if the requested rate can be
95 * divided from parent clock without any need to change
96 * parent rate, so return the divider immediately.
98 *best_parent_rate = parent_rate_saved;
102 parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
104 cur_rate = DIV_ROUND_UP(parent_rate, clkt->div) * clkt->mul;
105 if (cur_rate <= rate && cur_rate > best) {
108 *best_parent_rate = parent_rate;
113 bestval = _get_table_maxval(clkt);
114 *best_parent_rate = clk_hw_round_rate(
115 clk_hw_get_parent(hw), 1);
121 long owl_factor_helper_round_rate(struct owl_clk_common *common,
122 const struct owl_factor_hw *factor_hw,
124 unsigned long *parent_rate)
126 const struct clk_factor_table *clkt = factor_hw->table;
127 unsigned int val, mul = 0, div = 1;
129 val = clk_val_best(&common->hw, rate, parent_rate);
130 _get_table_div_mul(clkt, val, &mul, &div);
132 return *parent_rate * mul / div;
135 static long owl_factor_round_rate(struct clk_hw *hw, unsigned long rate,
136 unsigned long *parent_rate)
138 struct owl_factor *factor = hw_to_owl_factor(hw);
139 struct owl_factor_hw *factor_hw = &factor->factor_hw;
141 return owl_factor_helper_round_rate(&factor->common, factor_hw,
145 unsigned long owl_factor_helper_recalc_rate(struct owl_clk_common *common,
146 const struct owl_factor_hw *factor_hw,
147 unsigned long parent_rate)
149 const struct clk_factor_table *clkt = factor_hw->table;
150 unsigned long long int rate;
151 u32 reg, val, mul, div;
156 regmap_read(common->regmap, factor_hw->reg, ®);
158 val = reg >> factor_hw->shift;
159 val &= div_mask(factor_hw);
161 _get_table_div_mul(clkt, val, &mul, &div);
163 WARN(!(factor_hw->fct_flags & CLK_DIVIDER_ALLOW_ZERO),
164 "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
165 __clk_get_name(common->hw.clk));
169 rate = (unsigned long long int)parent_rate * mul;
175 static unsigned long owl_factor_recalc_rate(struct clk_hw *hw,
176 unsigned long parent_rate)
178 struct owl_factor *factor = hw_to_owl_factor(hw);
179 struct owl_factor_hw *factor_hw = &factor->factor_hw;
180 struct owl_clk_common *common = &factor->common;
182 return owl_factor_helper_recalc_rate(common, factor_hw, parent_rate);
185 int owl_factor_helper_set_rate(const struct owl_clk_common *common,
186 const struct owl_factor_hw *factor_hw,
188 unsigned long parent_rate)
192 val = _get_table_val(factor_hw->table, rate, parent_rate);
194 if (val > div_mask(factor_hw))
195 val = div_mask(factor_hw);
197 regmap_read(common->regmap, factor_hw->reg, ®);
199 reg &= ~(div_mask(factor_hw) << factor_hw->shift);
200 reg |= val << factor_hw->shift;
202 regmap_write(common->regmap, factor_hw->reg, reg);
207 static int owl_factor_set_rate(struct clk_hw *hw, unsigned long rate,
208 unsigned long parent_rate)
210 struct owl_factor *factor = hw_to_owl_factor(hw);
211 struct owl_factor_hw *factor_hw = &factor->factor_hw;
212 struct owl_clk_common *common = &factor->common;
214 return owl_factor_helper_set_rate(common, factor_hw,
218 const struct clk_ops owl_factor_ops = {
219 .round_rate = owl_factor_round_rate,
220 .recalc_rate = owl_factor_recalc_rate,
221 .set_rate = owl_factor_set_rate,