drivers/clk/sunxi-ng/ccu_nkm.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_nkm.h"
  15
  16 struct _ccu_nkm {
  17         unsigned long   n, min_n, max_n;
  18         unsigned long   k, min_k, max_k;
  19         unsigned long   m, min_m, max_m;
  20 };
  21
  22 static void ccu_nkm_find_best(unsigned long parent, unsigned long rate,
  23                               struct _ccu_nkm *nkm)
  24 {
  25         unsigned long best_rate = 0;
  26         unsigned long best_n = 0, best_k = 0, best_m = 0;
  27         unsigned long _n, _k, _m;
  28
  29         for (_k = nkm->min_k; _k <= nkm->max_k; _k++) {
  30                 for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
  31                         for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
  32                                 unsigned long tmp_rate;
  33
  34                                 tmp_rate = parent * _n * _k / _m;
  35
  36                                 if (tmp_rate > rate)
  37                                         continue;
  38                                 if ((rate - tmp_rate) < (rate - best_rate)) {
  39                                         best_rate = tmp_rate;
  40                                         best_n = _n;
  41                                         best_k = _k;
  42                                         best_m = _m;
  43                                 }
  44                         }
  45                 }
  46         }
  47
  48         nkm->n = best_n;
  49         nkm->k = best_k;
  50         nkm->m = best_m;
  51 }
  52
  53 static void ccu_nkm_disable(struct clk_hw *hw)
  54 {
  55         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
  56
  57         return ccu_gate_helper_disable(&nkm->common, nkm->enable);
  58 }
  59
  60 static int ccu_nkm_enable(struct clk_hw *hw)
  61 {
  62         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
  63
  64         return ccu_gate_helper_enable(&nkm->common, nkm->enable);
  65 }
  66
  67 static int ccu_nkm_is_enabled(struct clk_hw *hw)
  68 {
  69         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
  70
  71         return ccu_gate_helper_is_enabled(&nkm->common, nkm->enable);
  72 }
  73
  74 static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
  75                                         unsigned long parent_rate)
  76 {
  77         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
  78         unsigned long n, m, k;
  79         u32 reg;
  80
  81         reg = readl(nkm->common.base + nkm->common.reg);
  82
  83         n = reg >> nkm->n.shift;
  84         n &= (1 << nkm->n.width) - 1;
  85
  86         k = reg >> nkm->k.shift;
  87         k &= (1 << nkm->k.width) - 1;
  88
  89         m = reg >> nkm->m.shift;
  90         m &= (1 << nkm->m.width) - 1;
  91
  92         return parent_rate * (n + 1) * (k + 1) / (m + 1);
  93 }
  94
  95 static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
  96                                         unsigned long parent_rate,
  97                                         unsigned long rate,
  98                                         void *data)
  99 {
 100         struct ccu_nkm *nkm = data;
 101         struct _ccu_nkm _nkm;
 102
 103         _nkm.min_n = nkm->n.min;
 104         _nkm.max_n = 1 << nkm->n.width;
 105         _nkm.min_k = nkm->k.min;
 106         _nkm.max_k = 1 << nkm->k.width;
 107         _nkm.min_m = 1;
 108         _nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;
 109
 110         ccu_nkm_find_best(parent_rate, rate, &_nkm);
 111
 112         return parent_rate * _nkm.n * _nkm.k / _nkm.m;
 113 }
 114
 115 static int ccu_nkm_determine_rate(struct clk_hw *hw,
 116                                   struct clk_rate_request *req)
 117 {
 118         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 119
 120         return ccu_mux_helper_determine_rate(&nkm->common, &nkm->mux,
 121                                              req, ccu_nkm_round_rate, nkm);
 122 }
 123
 124 static int ccu_nkm_set_rate(struct clk_hw *hw, unsigned long rate,
 125                            unsigned long parent_rate)
 126 {
 127         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 128         struct _ccu_nkm _nkm;
 129         unsigned long flags;
 130         u32 reg;
 131
 132         _nkm.min_n = nkm->n.min;
 133         _nkm.max_n = 1 << nkm->n.width;
 134         _nkm.min_k = nkm->k.min;
 135         _nkm.max_k = 1 << nkm->k.width;
 136         _nkm.min_m = 1;
 137         _nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;
 138
 139         ccu_nkm_find_best(parent_rate, rate, &_nkm);
 140
 141         spin_lock_irqsave(nkm->common.lock, flags);
 142
 143         reg = readl(nkm->common.base + nkm->common.reg);
 144         reg &= ~GENMASK(nkm->n.width + nkm->n.shift - 1, nkm->n.shift);
 145         reg &= ~GENMASK(nkm->k.width + nkm->k.shift - 1, nkm->k.shift);
 146         reg &= ~GENMASK(nkm->m.width + nkm->m.shift - 1, nkm->m.shift);
 147
 148         reg |= (_nkm.n - 1) << nkm->n.shift;
 149         reg |= (_nkm.k - 1) << nkm->k.shift;
 150         reg |= (_nkm.m - 1) << nkm->m.shift;
 151
 152         writel(reg, nkm->common.base + nkm->common.reg);
 153
 154         spin_unlock_irqrestore(nkm->common.lock, flags);
 155
 156         ccu_helper_wait_for_lock(&nkm->common, nkm->lock);
 157
 158         return 0;
 159 }
 160
 161 static u8 ccu_nkm_get_parent(struct clk_hw *hw)
 162 {
 163         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 164
 165         return ccu_mux_helper_get_parent(&nkm->common, &nkm->mux);
 166 }
 167
 168 static int ccu_nkm_set_parent(struct clk_hw *hw, u8 index)
 169 {
 170         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 171
 172         return ccu_mux_helper_set_parent(&nkm->common, &nkm->mux, index);
 173 }
 174
 175 const struct clk_ops ccu_nkm_ops = {
 176         .disable        = ccu_nkm_disable,
 177         .enable         = ccu_nkm_enable,
 178         .is_enabled     = ccu_nkm_is_enabled,
 179
 180         .get_parent     = ccu_nkm_get_parent,
 181         .set_parent     = ccu_nkm_set_parent,
 182
 183         .determine_rate = ccu_nkm_determine_rate,
 184         .recalc_rate    = ccu_nkm_recalc_rate,
 185         .set_rate       = ccu_nkm_set_rate,
 186 };