1 /* 2 * Copyright (C) 2016 Maxime Ripard 3 * Maxime Ripard <maxime.ripard@free-electrons.com> 4 * 5 * This program is free software; you can redistribute it and/or 6 * modify it under the terms of the GNU General Public License as 7 * published by the Free Software Foundation; either version 2 of 8 * the License, or (at your option) any later version. 9 */ 10 11 #include <linux/clk-provider.h> 12 13 #include "ccu_frac.h" 14 #include "ccu_gate.h" 15 #include "ccu_nm.h" 16 17 struct _ccu_nm { 18 unsigned long n, min_n, max_n; 19 unsigned long m, min_m, max_m; 20 }; 21 22 static void ccu_nm_find_best(unsigned long parent, unsigned long rate, 23 struct _ccu_nm *nm) 24 { 25 unsigned long best_rate = 0; 26 unsigned long best_n = 0, best_m = 0; 27 unsigned long _n, _m; 28 29 for (_n = nm->min_n; _n <= nm->max_n; _n++) { 30 for (_m = nm->min_m; _m <= nm->max_m; _m++) { 31 unsigned long tmp_rate = parent * _n / _m; 32 33 if (tmp_rate > rate) 34 continue; 35 36 if ((rate - tmp_rate) < (rate - best_rate)) { 37 best_rate = tmp_rate; 38 best_n = _n; 39 best_m = _m; 40 } 41 } 42 } 43 44 nm->n = best_n; 45 nm->m = best_m; 46 } 47 48 static void ccu_nm_disable(struct clk_hw *hw) 49 { 50 struct ccu_nm *nm = hw_to_ccu_nm(hw); 51 52 return ccu_gate_helper_disable(&nm->common, nm->enable); 53 } 54 55 static int ccu_nm_enable(struct clk_hw *hw) 56 { 57 struct ccu_nm *nm = hw_to_ccu_nm(hw); 58 59 return ccu_gate_helper_enable(&nm->common, nm->enable); 60 } 61 62 static int ccu_nm_is_enabled(struct clk_hw *hw) 63 { 64 struct ccu_nm *nm = hw_to_ccu_nm(hw); 65 66 return ccu_gate_helper_is_enabled(&nm->common, nm->enable); 67 } 68 69 static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw, 70 unsigned long parent_rate) 71 { 72 struct ccu_nm *nm = hw_to_ccu_nm(hw); 73 unsigned long n, m; 74 u32 reg; 75 76 if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac)) 77 return ccu_frac_helper_read_rate(&nm->common, &nm->frac); 78 79 reg = readl(nm->common.base + nm->common.reg); 80 81 n = reg >> nm->n.shift; 82 n &= (1 << nm->n.width) - 1; 83 n += nm->n.offset; 84 if (!n) 85 n++; 86 87 m = reg >> nm->m.shift; 88 m &= (1 << nm->m.width) - 1; 89 m += nm->m.offset; 90 if (!m) 91 m++; 92 93 return parent_rate * n / m; 94 } 95 96 static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate, 97 unsigned long *parent_rate) 98 { 99 struct ccu_nm *nm = hw_to_ccu_nm(hw); 100 struct _ccu_nm _nm; 101 102 _nm.min_n = nm->n.min; 103 _nm.max_n = 1 << nm->n.width; 104 _nm.min_m = 1; 105 _nm.max_m = nm->m.max ?: 1 << nm->m.width; 106 107 ccu_nm_find_best(*parent_rate, rate, &_nm); 108 109 return *parent_rate * _nm.n / _nm.m; 110 } 111 112 static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate, 113 unsigned long parent_rate) 114 { 115 struct ccu_nm *nm = hw_to_ccu_nm(hw); 116 struct _ccu_nm _nm; 117 unsigned long flags; 118 u32 reg; 119 120 if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) 121 return ccu_frac_helper_set_rate(&nm->common, &nm->frac, rate); 122 else 123 ccu_frac_helper_disable(&nm->common, &nm->frac); 124 125 _nm.min_n = 1; 126 _nm.max_n = 1 << nm->n.width; 127 _nm.min_m = 1; 128 _nm.max_m = nm->m.max ?: 1 << nm->m.width; 129 130 ccu_nm_find_best(parent_rate, rate, &_nm); 131 132 spin_lock_irqsave(nm->common.lock, flags); 133 134 reg = readl(nm->common.base + nm->common.reg); 135 reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift); 136 reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift); 137 138 reg |= (_nm.n - nm->n.offset) << nm->n.shift; 139 reg |= (_nm.m - nm->m.offset) << nm->m.shift; 140 writel(reg, nm->common.base + nm->common.reg); 141 142 spin_unlock_irqrestore(nm->common.lock, flags); 143 144 ccu_helper_wait_for_lock(&nm->common, nm->lock); 145 146 return 0; 147 } 148 149 const struct clk_ops ccu_nm_ops = { 150 .disable = ccu_nm_disable, 151 .enable = ccu_nm_enable, 152 .is_enabled = ccu_nm_is_enabled, 153 154 .recalc_rate = ccu_nm_recalc_rate, 155 .round_rate = ccu_nm_round_rate, 156 .set_rate = ccu_nm_set_rate, 157 }; 158