drivers/clk/sunxi-ng/ccu_mp.c

   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_gate.h"
  14 #include "ccu_mp.h"
  15
  16 static void ccu_mp_find_best(unsigned long parent, unsigned long rate,
  17                              unsigned int max_m, unsigned int max_p,
  18                              unsigned int *m, unsigned int *p)
  19 {
  20         unsigned long best_rate = 0;
  21         unsigned int best_m = 0, best_p = 0;
  22         unsigned int _m, _p;
  23
  24         for (_p = 1; _p <= max_p; _p <<= 1) {
  25                 for (_m = 1; _m <= max_m; _m++) {
  26                         unsigned long tmp_rate = parent / _p / _m;
  27
  28                         if (tmp_rate > rate)
  29                                 continue;
  30
  31                         if ((rate - tmp_rate) < (rate - best_rate)) {
  32                                 best_rate = tmp_rate;
  33                                 best_m = _m;
  34                                 best_p = _p;
  35                         }
  36                 }
  37         }
  38
  39         *m = best_m;
  40         *p = best_p;
  41 }
  42
  43 static unsigned long ccu_mp_round_rate(struct ccu_mux_internal *mux,
  44                                        unsigned long parent_rate,
  45                                        unsigned long rate,
  46                                        void *data)
  47 {
  48         struct ccu_mp *cmp = data;
  49         unsigned int max_m, max_p;
  50         unsigned int m, p;
  51
  52         max_m = cmp->m.max ?: 1 << cmp->m.width;
  53         max_p = cmp->p.max ?: 1 << ((1 << cmp->p.width) - 1);
  54
  55         ccu_mp_find_best(parent_rate, rate, max_m, max_p, &m, &p);
  56
  57         return parent_rate / p / m;
  58 }
  59
  60 static void ccu_mp_disable(struct clk_hw *hw)
  61 {
  62         struct ccu_mp *cmp = hw_to_ccu_mp(hw);
  63
  64         return ccu_gate_helper_disable(&cmp->common, cmp->enable);
  65 }
  66
  67 static int ccu_mp_enable(struct clk_hw *hw)
  68 {
  69         struct ccu_mp *cmp = hw_to_ccu_mp(hw);
  70
  71         return ccu_gate_helper_enable(&cmp->common, cmp->enable);
  72 }
  73
  74 static int ccu_mp_is_enabled(struct clk_hw *hw)
  75 {
  76         struct ccu_mp *cmp = hw_to_ccu_mp(hw);
  77
  78         return ccu_gate_helper_is_enabled(&cmp->common, cmp->enable);
  79 }
  80
  81 static unsigned long ccu_mp_recalc_rate(struct clk_hw *hw,
  82                                         unsigned long parent_rate)
  83 {
  84         struct ccu_mp *cmp = hw_to_ccu_mp(hw);
  85         unsigned int m, p;
  86         u32 reg;
  87
  88         reg = readl(cmp->common.base + cmp->common.reg);
  89
  90         m = reg >> cmp->m.shift;
  91         m &= (1 << cmp->m.width) - 1;
  92
  93         p = reg >> cmp->p.shift;
  94         p &= (1 << cmp->p.width) - 1;
  95
  96         return (parent_rate >> p) / (m + 1);
  97 }
  98
  99 static int ccu_mp_determine_rate(struct clk_hw *hw,
 100                                  struct clk_rate_request *req)
 101 {
 102         struct ccu_mp *cmp = hw_to_ccu_mp(hw);
 103
 104         return ccu_mux_helper_determine_rate(&cmp->common, &cmp->mux,
 105                                              req, ccu_mp_round_rate, cmp);
 106 }
 107
 108 static int ccu_mp_set_rate(struct clk_hw *hw, unsigned long rate,
 109                            unsigned long parent_rate)
 110 {
 111         struct ccu_mp *cmp = hw_to_ccu_mp(hw);
 112         unsigned long flags;
 113         unsigned int max_m, max_p;
 114         unsigned int m, p;
 115         u32 reg;
 116
 117         max_m = cmp->m.max ?: 1 << cmp->m.width;
 118         max_p = cmp->p.max ?: 1 << ((1 << cmp->p.width) - 1);
 119
 120         ccu_mp_find_best(parent_rate, rate, max_m, max_p, &m, &p);
 121
 122         spin_lock_irqsave(cmp->common.lock, flags);
 123
 124         reg = readl(cmp->common.base + cmp->common.reg);
 125         reg &= ~GENMASK(cmp->m.width + cmp->m.shift - 1, cmp->m.shift);
 126         reg &= ~GENMASK(cmp->p.width + cmp->p.shift - 1, cmp->p.shift);
 127
 128         writel(reg | (ilog2(p) << cmp->p.shift) | ((m - 1) << cmp->m.shift),
 129                cmp->common.base + cmp->common.reg);
 130
 131         spin_unlock_irqrestore(cmp->common.lock, flags);
 132
 133         return 0;
 134 }
 135
 136 static u8 ccu_mp_get_parent(struct clk_hw *hw)
 137 {
 138         struct ccu_mp *cmp = hw_to_ccu_mp(hw);
 139
 140         return ccu_mux_helper_get_parent(&cmp->common, &cmp->mux);
 141 }
 142
 143 static int ccu_mp_set_parent(struct clk_hw *hw, u8 index)
 144 {
 145         struct ccu_mp *cmp = hw_to_ccu_mp(hw);
 146
 147         return ccu_mux_helper_set_parent(&cmp->common, &cmp->mux, index);
 148 }
 149
 150 const struct clk_ops ccu_mp_ops = {
 151         .disable        = ccu_mp_disable,
 152         .enable         = ccu_mp_enable,
 153         .is_enabled     = ccu_mp_is_enabled,
 154
 155         .get_parent     = ccu_mp_get_parent,
 156         .set_parent     = ccu_mp_set_parent,
 157
 158         .determine_rate = ccu_mp_determine_rate,
 159         .recalc_rate    = ccu_mp_recalc_rate,
 160         .set_rate       = ccu_mp_set_rate,
 161 };