1 /* 2 * mmp factor clock operation source file 3 * 4 * Copyright (C) 2012 Marvell 5 * Chao Xie <xiechao.mail@gmail.com> 6 * 7 * This file is licensed under the terms of the GNU General Public 8 * License version 2. This program is licensed "as is" without any 9 * warranty of any kind, whether express or implied. 10 */ 11 12 #include <linux/clk-provider.h> 13 #include <linux/slab.h> 14 #include <linux/io.h> 15 #include <linux/err.h> 16 17 #include "clk.h" 18 /* 19 * It is M/N clock 20 * 21 * Fout from synthesizer can be given from two equations: 22 * numerator/denominator = Fin / (Fout * factor) 23 */ 24 25 #define to_clk_factor(hw) container_of(hw, struct clk_factor, hw) 26 struct clk_factor { 27 struct clk_hw hw; 28 void __iomem *base; 29 struct clk_factor_masks *masks; 30 struct clk_factor_tbl *ftbl; 31 unsigned int ftbl_cnt; 32 }; 33 34 static long clk_factor_round_rate(struct clk_hw *hw, unsigned long drate, 35 unsigned long *prate) 36 { 37 struct clk_factor *factor = to_clk_factor(hw); 38 unsigned long rate = 0, prev_rate; 39 int i; 40 41 for (i = 0; i < factor->ftbl_cnt; i++) { 42 prev_rate = rate; 43 rate = (((*prate / 10000) * factor->ftbl[i].den) / 44 (factor->ftbl[i].num * factor->masks->factor)) * 10000; 45 if (rate > drate) 46 break; 47 } 48 if ((i == 0) || (i == factor->ftbl_cnt)) { 49 return rate; 50 } else { 51 if ((drate - prev_rate) > (rate - drate)) 52 return rate; 53 else 54 return prev_rate; 55 } 56 } 57 58 static unsigned long clk_factor_recalc_rate(struct clk_hw *hw, 59 unsigned long parent_rate) 60 { 61 struct clk_factor *factor = to_clk_factor(hw); 62 struct clk_factor_masks *masks = factor->masks; 63 unsigned int val, num, den; 64 65 val = readl_relaxed(factor->base); 66 67 /* calculate numerator */ 68 num = (val >> masks->num_shift) & masks->num_mask; 69 70 /* calculate denominator */ 71 den = (val >> masks->den_shift) & masks->den_mask; 72 73 if (!den) 74 return 0; 75 76 return (((parent_rate / 10000) * den) / 77 (num * factor->masks->factor)) * 10000; 78 } 79 80 /* Configures new clock rate*/ 81 static int clk_factor_set_rate(struct clk_hw *hw, unsigned long drate, 82 unsigned long prate) 83 { 84 struct clk_factor *factor = to_clk_factor(hw); 85 struct clk_factor_masks *masks = factor->masks; 86 int i; 87 unsigned long val; 88 unsigned long prev_rate, rate = 0; 89 90 for (i = 0; i < factor->ftbl_cnt; i++) { 91 prev_rate = rate; 92 rate = (((prate / 10000) * factor->ftbl[i].den) / 93 (factor->ftbl[i].num * factor->masks->factor)) * 10000; 94 if (rate > drate) 95 break; 96 } 97 if (i > 0) 98 i--; 99 100 val = readl_relaxed(factor->base); 101 102 val &= ~(masks->num_mask << masks->num_shift); 103 val |= (factor->ftbl[i].num & masks->num_mask) << masks->num_shift; 104 105 val &= ~(masks->den_mask << masks->den_shift); 106 val |= (factor->ftbl[i].den & masks->den_mask) << masks->den_shift; 107 108 writel_relaxed(val, factor->base); 109 110 return 0; 111 } 112 113 static struct clk_ops clk_factor_ops = { 114 .recalc_rate = clk_factor_recalc_rate, 115 .round_rate = clk_factor_round_rate, 116 .set_rate = clk_factor_set_rate, 117 }; 118 119 struct clk *mmp_clk_register_factor(const char *name, const char *parent_name, 120 unsigned long flags, void __iomem *base, 121 struct clk_factor_masks *masks, struct clk_factor_tbl *ftbl, 122 unsigned int ftbl_cnt) 123 { 124 struct clk_factor *factor; 125 struct clk_init_data init; 126 struct clk *clk; 127 128 if (!masks) { 129 pr_err("%s: must pass a clk_factor_mask\n", __func__); 130 return ERR_PTR(-EINVAL); 131 } 132 133 factor = kzalloc(sizeof(*factor), GFP_KERNEL); 134 if (!factor) { 135 pr_err("%s: could not allocate factor clk\n", __func__); 136 return ERR_PTR(-ENOMEM); 137 } 138 139 /* struct clk_aux assignments */ 140 factor->base = base; 141 factor->masks = masks; 142 factor->ftbl = ftbl; 143 factor->ftbl_cnt = ftbl_cnt; 144 factor->hw.init = &init; 145 146 init.name = name; 147 init.ops = &clk_factor_ops; 148 init.flags = flags; 149 init.parent_names = &parent_name; 150 init.num_parents = 1; 151 152 clk = clk_register(NULL, &factor->hw); 153 if (IS_ERR_OR_NULL(clk)) 154 kfree(factor); 155 156 return clk; 157 } 158