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].num) / 44 (factor->ftbl[i].den * factor->masks->factor)) * 10000; 45 if (rate > drate) 46 break; 47 } 48 if (i == 0) 49 return rate; 50 else 51 return prev_rate; 52 } 53 54 static unsigned long clk_factor_recalc_rate(struct clk_hw *hw, 55 unsigned long parent_rate) 56 { 57 struct clk_factor *factor = to_clk_factor(hw); 58 struct clk_factor_masks *masks = factor->masks; 59 unsigned int val, num, den; 60 61 val = readl_relaxed(factor->base); 62 63 /* calculate numerator */ 64 num = (val >> masks->num_shift) & masks->num_mask; 65 66 /* calculate denominator */ 67 den = (val >> masks->den_shift) & masks->num_mask; 68 69 if (!den) 70 return 0; 71 72 return (((parent_rate / 10000) * den) / 73 (num * factor->masks->factor)) * 10000; 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 clk_factor *factor = to_clk_factor(hw); 81 struct clk_factor_masks *masks = factor->masks; 82 int i; 83 unsigned long val; 84 unsigned long prev_rate, rate = 0; 85 86 for (i = 0; i < factor->ftbl_cnt; i++) { 87 prev_rate = rate; 88 rate = (((prate / 10000) * factor->ftbl[i].num) / 89 (factor->ftbl[i].den * factor->masks->factor)) * 10000; 90 if (rate > drate) 91 break; 92 } 93 if (i > 0) 94 i--; 95 96 val = readl_relaxed(factor->base); 97 98 val &= ~(masks->num_mask << masks->num_shift); 99 val |= (factor->ftbl[i].num & masks->num_mask) << masks->num_shift; 100 101 val &= ~(masks->den_mask << masks->den_shift); 102 val |= (factor->ftbl[i].den & masks->den_mask) << masks->den_shift; 103 104 writel_relaxed(val, factor->base); 105 106 return 0; 107 } 108 109 static struct clk_ops clk_factor_ops = { 110 .recalc_rate = clk_factor_recalc_rate, 111 .round_rate = clk_factor_round_rate, 112 .set_rate = clk_factor_set_rate, 113 }; 114 115 struct clk *mmp_clk_register_factor(const char *name, const char *parent_name, 116 unsigned long flags, void __iomem *base, 117 struct clk_factor_masks *masks, struct clk_factor_tbl *ftbl, 118 unsigned int ftbl_cnt) 119 { 120 struct clk_factor *factor; 121 struct clk_init_data init; 122 struct clk *clk; 123 124 if (!masks) { 125 pr_err("%s: must pass a clk_factor_mask\n", __func__); 126 return ERR_PTR(-EINVAL); 127 } 128 129 factor = kzalloc(sizeof(*factor), GFP_KERNEL); 130 if (!factor) { 131 pr_err("%s: could not allocate factor clk\n", __func__); 132 return ERR_PTR(-ENOMEM); 133 } 134 135 /* struct clk_aux assignments */ 136 factor->base = base; 137 factor->masks = masks; 138 factor->ftbl = ftbl; 139 factor->ftbl_cnt = ftbl_cnt; 140 factor->hw.init = &init; 141 142 init.name = name; 143 init.ops = &clk_factor_ops; 144 init.flags = flags; 145 init.parent_names = &parent_name; 146 init.num_parents = 1; 147 148 clk = clk_register(NULL, &factor->hw); 149 if (IS_ERR_OR_NULL(clk)) 150 kfree(factor); 151 152 return clk; 153 } 154