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 #include <linux/slab.h> 14 15 #include "owl-factor.h" 16 17 static unsigned int _get_table_maxval(const struct clk_factor_table *table) 18 { 19 unsigned int maxval = 0; 20 const struct clk_factor_table *clkt; 21 22 for (clkt = table; clkt->div; clkt++) 23 if (clkt->val > maxval) 24 maxval = clkt->val; 25 return maxval; 26 } 27 28 static int _get_table_div_mul(const struct clk_factor_table *table, 29 unsigned int val, unsigned int *mul, unsigned int *div) 30 { 31 const struct clk_factor_table *clkt; 32 33 for (clkt = table; clkt->div; clkt++) { 34 if (clkt->val == val) { 35 *mul = clkt->mul; 36 *div = clkt->div; 37 return 1; 38 } 39 } 40 41 return 0; 42 } 43 44 static unsigned int _get_table_val(const struct clk_factor_table *table, 45 unsigned long rate, unsigned long parent_rate) 46 { 47 const struct clk_factor_table *clkt; 48 int val = -1; 49 u64 calc_rate; 50 51 for (clkt = table; clkt->div; clkt++) { 52 calc_rate = parent_rate * clkt->mul; 53 do_div(calc_rate, clkt->div); 54 55 if ((unsigned long)calc_rate <= rate) { 56 val = clkt->val; 57 break; 58 } 59 } 60 61 if (val == -1) 62 val = _get_table_maxval(table); 63 64 return val; 65 } 66 67 static int clk_val_best(struct clk_hw *hw, unsigned long rate, 68 unsigned long *best_parent_rate) 69 { 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; 75 int bestval = 0; 76 77 if (!rate) 78 rate = 1; 79 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); 83 return bestval; 84 } 85 86 for (clkt = factor_hw->table; clkt->div; clkt++) { 87 try_parent_rate = rate * clkt->div / clkt->mul; 88 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, 92 try_parent_rate); 93 /* 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. 97 */ 98 *best_parent_rate = parent_rate_saved; 99 return clkt->val; 100 } 101 102 parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw), 103 try_parent_rate); 104 cur_rate = DIV_ROUND_UP(parent_rate, clkt->div) * clkt->mul; 105 if (cur_rate <= rate && cur_rate > best) { 106 bestval = clkt->val; 107 best = cur_rate; 108 *best_parent_rate = parent_rate; 109 } 110 } 111 112 if (!bestval) { 113 bestval = _get_table_maxval(clkt); 114 *best_parent_rate = clk_hw_round_rate( 115 clk_hw_get_parent(hw), 1); 116 } 117 118 return bestval; 119 } 120 121 long owl_factor_helper_round_rate(struct owl_clk_common *common, 122 const struct owl_factor_hw *factor_hw, 123 unsigned long rate, 124 unsigned long *parent_rate) 125 { 126 const struct clk_factor_table *clkt = factor_hw->table; 127 unsigned int val, mul = 0, div = 1; 128 129 val = clk_val_best(&common->hw, rate, parent_rate); 130 _get_table_div_mul(clkt, val, &mul, &div); 131 132 return *parent_rate * mul / div; 133 } 134 135 static long owl_factor_round_rate(struct clk_hw *hw, unsigned long rate, 136 unsigned long *parent_rate) 137 { 138 struct owl_factor *factor = hw_to_owl_factor(hw); 139 struct owl_factor_hw *factor_hw = &factor->factor_hw; 140 141 return owl_factor_helper_round_rate(&factor->common, factor_hw, 142 rate, parent_rate); 143 } 144 145 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) 148 { 149 const struct clk_factor_table *clkt = factor_hw->table; 150 unsigned long long int rate; 151 u32 reg, val, mul, div; 152 153 div = 0; 154 mul = 0; 155 156 regmap_read(common->regmap, factor_hw->reg, ®); 157 158 val = reg >> factor_hw->shift; 159 val &= div_mask(factor_hw); 160 161 _get_table_div_mul(clkt, val, &mul, &div); 162 if (!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)); 166 return parent_rate; 167 } 168 169 rate = (unsigned long long int)parent_rate * mul; 170 do_div(rate, div); 171 172 return rate; 173 } 174 175 static unsigned long owl_factor_recalc_rate(struct clk_hw *hw, 176 unsigned long parent_rate) 177 { 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; 181 182 return owl_factor_helper_recalc_rate(common, factor_hw, parent_rate); 183 } 184 185 int owl_factor_helper_set_rate(const struct owl_clk_common *common, 186 const struct owl_factor_hw *factor_hw, 187 unsigned long rate, 188 unsigned long parent_rate) 189 { 190 u32 val, reg; 191 192 val = _get_table_val(factor_hw->table, rate, parent_rate); 193 194 if (val > div_mask(factor_hw)) 195 val = div_mask(factor_hw); 196 197 regmap_read(common->regmap, factor_hw->reg, ®); 198 199 reg &= ~(div_mask(factor_hw) << factor_hw->shift); 200 reg |= val << factor_hw->shift; 201 202 regmap_write(common->regmap, factor_hw->reg, reg); 203 204 return 0; 205 } 206 207 static int owl_factor_set_rate(struct clk_hw *hw, unsigned long rate, 208 unsigned long parent_rate) 209 { 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; 213 214 return owl_factor_helper_set_rate(common, factor_hw, 215 rate, parent_rate); 216 } 217 218 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, 222 }; 223