1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * mmp factor clock operation source file 4 * 5 * Copyright (C) 2012 Marvell 6 * Chao Xie <xiechao.mail@gmail.com> 7 */ 8 9 #include <linux/clk-provider.h> 10 #include <linux/slab.h> 11 #include <linux/io.h> 12 #include <linux/err.h> 13 14 #include "clk.h" 15 /* 16 * It is M/N clock 17 * 18 * Fout from synthesizer can be given from two equations: 19 * numerator/denominator = Fin / (Fout * factor) 20 */ 21 22 #define to_clk_factor(hw) container_of(hw, struct mmp_clk_factor, hw) 23 24 static long clk_factor_round_rate(struct clk_hw *hw, unsigned long drate, 25 unsigned long *prate) 26 { 27 struct mmp_clk_factor *factor = to_clk_factor(hw); 28 u64 rate = 0, prev_rate; 29 struct u32_fract *d; 30 int i; 31 32 for (i = 0; i < factor->ftbl_cnt; i++) { 33 d = &factor->ftbl[i]; 34 35 prev_rate = rate; 36 rate = (u64)(*prate) * d->denominator; 37 do_div(rate, d->numerator * factor->masks->factor); 38 if (rate > drate) 39 break; 40 } 41 if ((i == 0) || (i == factor->ftbl_cnt)) { 42 return rate; 43 } else { 44 if ((drate - prev_rate) > (rate - drate)) 45 return rate; 46 else 47 return prev_rate; 48 } 49 } 50 51 static unsigned long clk_factor_recalc_rate(struct clk_hw *hw, 52 unsigned long parent_rate) 53 { 54 struct mmp_clk_factor *factor = to_clk_factor(hw); 55 struct mmp_clk_factor_masks *masks = factor->masks; 56 struct u32_fract d; 57 unsigned int val; 58 u64 rate; 59 60 val = readl_relaxed(factor->base); 61 62 /* calculate numerator */ 63 d.numerator = (val >> masks->num_shift) & masks->num_mask; 64 65 /* calculate denominator */ 66 d.denominator = (val >> masks->den_shift) & masks->den_mask; 67 if (!d.denominator) 68 return 0; 69 70 rate = (u64)parent_rate * d.denominator; 71 do_div(rate, d.numerator * factor->masks->factor); 72 73 return rate; 74 } 75 76 /* Configures new clock rate*/ 77 static int clk_factor_set_rate(struct clk_hw *hw, unsigned long drate, 78 unsigned long prate) 79 { 80 struct mmp_clk_factor *factor = to_clk_factor(hw); 81 struct mmp_clk_factor_masks *masks = factor->masks; 82 int i; 83 unsigned long val; 84 unsigned long flags = 0; 85 struct u32_fract *d; 86 u64 rate = 0; 87 88 for (i = 0; i < factor->ftbl_cnt; i++) { 89 d = &factor->ftbl[i]; 90 91 rate = (u64)prate * d->denominator; 92 do_div(rate, d->numerator * factor->masks->factor); 93 if (rate > drate) 94 break; 95 } 96 d = i ? &factor->ftbl[i - 1] : &factor->ftbl[0]; 97 98 if (factor->lock) 99 spin_lock_irqsave(factor->lock, flags); 100 101 val = readl_relaxed(factor->base); 102 103 val &= ~(masks->num_mask << masks->num_shift); 104 val |= (d->numerator & masks->num_mask) << masks->num_shift; 105 106 val &= ~(masks->den_mask << masks->den_shift); 107 val |= (d->denominator & masks->den_mask) << masks->den_shift; 108 109 writel_relaxed(val, factor->base); 110 111 if (factor->lock) 112 spin_unlock_irqrestore(factor->lock, flags); 113 114 return 0; 115 } 116 117 static int clk_factor_init(struct clk_hw *hw) 118 { 119 struct mmp_clk_factor *factor = to_clk_factor(hw); 120 struct mmp_clk_factor_masks *masks = factor->masks; 121 struct u32_fract d; 122 u32 val; 123 int i; 124 unsigned long flags = 0; 125 126 if (factor->lock) 127 spin_lock_irqsave(factor->lock, flags); 128 129 val = readl(factor->base); 130 131 /* calculate numerator */ 132 d.numerator = (val >> masks->num_shift) & masks->num_mask; 133 134 /* calculate denominator */ 135 d.denominator = (val >> masks->den_shift) & masks->den_mask; 136 137 for (i = 0; i < factor->ftbl_cnt; i++) 138 if (d.denominator == factor->ftbl[i].denominator && 139 d.numerator == factor->ftbl[i].numerator) 140 break; 141 142 if (i >= factor->ftbl_cnt) { 143 val &= ~(masks->num_mask << masks->num_shift); 144 val |= (factor->ftbl[0].numerator & masks->num_mask) << masks->num_shift; 145 146 val &= ~(masks->den_mask << masks->den_shift); 147 val |= (factor->ftbl[0].denominator & masks->den_mask) << masks->den_shift; 148 } 149 150 if (!(val & masks->enable_mask) || i >= factor->ftbl_cnt) { 151 val |= masks->enable_mask; 152 writel(val, factor->base); 153 } 154 155 if (factor->lock) 156 spin_unlock_irqrestore(factor->lock, flags); 157 158 return 0; 159 } 160 161 static const struct clk_ops clk_factor_ops = { 162 .recalc_rate = clk_factor_recalc_rate, 163 .round_rate = clk_factor_round_rate, 164 .set_rate = clk_factor_set_rate, 165 .init = clk_factor_init, 166 }; 167 168 struct clk *mmp_clk_register_factor(const char *name, const char *parent_name, 169 unsigned long flags, void __iomem *base, 170 struct mmp_clk_factor_masks *masks, 171 struct u32_fract *ftbl, unsigned int ftbl_cnt, spinlock_t *lock) 172 { 173 struct mmp_clk_factor *factor; 174 struct clk_init_data init; 175 struct clk *clk; 176 177 if (!masks) { 178 pr_err("%s: must pass a clk_factor_mask\n", __func__); 179 return ERR_PTR(-EINVAL); 180 } 181 182 factor = kzalloc(sizeof(*factor), GFP_KERNEL); 183 if (!factor) 184 return ERR_PTR(-ENOMEM); 185 186 /* struct clk_aux assignments */ 187 factor->base = base; 188 factor->masks = masks; 189 factor->ftbl = ftbl; 190 factor->ftbl_cnt = ftbl_cnt; 191 factor->hw.init = &init; 192 factor->lock = lock; 193 194 init.name = name; 195 init.ops = &clk_factor_ops; 196 init.flags = flags; 197 init.parent_names = &parent_name; 198 init.num_parents = 1; 199 200 clk = clk_register(NULL, &factor->hw); 201 if (IS_ERR_OR_NULL(clk)) 202 kfree(factor); 203 204 return clk; 205 } 206