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, rate;
  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         n += nkm->n.offset;
  86         if (!n)
  87                 n++;
  88
  89         k = reg >> nkm->k.shift;
  90         k &= (1 << nkm->k.width) - 1;
  91         k += nkm->k.offset;
  92         if (!k)
  93                 k++;
  94
  95         m = reg >> nkm->m.shift;
  96         m &= (1 << nkm->m.width) - 1;
  97         m += nkm->m.offset;
  98         if (!m)
  99                 m++;
 100
 101         rate = parent_rate * n  * k / m;
 102
 103         if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 104                 rate /= nkm->fixed_post_div;
 105
 106         return rate;
 107 }
 108
 109 static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
 110                                         struct clk_hw *hw,
 111                                         unsigned long *parent_rate,
 112                                         unsigned long rate,
 113                                         void *data)
 114 {
 115         struct ccu_nkm *nkm = data;
 116         struct _ccu_nkm _nkm;
 117
 118         _nkm.min_n = nkm->n.min ?: 1;
 119         _nkm.max_n = nkm->n.max ?: 1 << nkm->n.width;
 120         _nkm.min_k = nkm->k.min ?: 1;
 121         _nkm.max_k = nkm->k.max ?: 1 << nkm->k.width;
 122         _nkm.min_m = 1;
 123         _nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;
 124
 125         if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 126                 rate *= nkm->fixed_post_div;
 127
 128         ccu_nkm_find_best(*parent_rate, rate, &_nkm);
 129
 130         rate = *parent_rate * _nkm.n * _nkm.k / _nkm.m;
 131
 132         if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 133                 rate /= nkm->fixed_post_div;
 134
 135         return rate;
 136 }
 137
 138 static int ccu_nkm_determine_rate(struct clk_hw *hw,
 139                                   struct clk_rate_request *req)
 140 {
 141         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 142
 143         return ccu_mux_helper_determine_rate(&nkm->common, &nkm->mux,
 144                                              req, ccu_nkm_round_rate, nkm);
 145 }
 146
 147 static int ccu_nkm_set_rate(struct clk_hw *hw, unsigned long rate,
 148                            unsigned long parent_rate)
 149 {
 150         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 151         struct _ccu_nkm _nkm;
 152         unsigned long flags;
 153         u32 reg;
 154
 155         if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 156                 rate *= nkm->fixed_post_div;
 157
 158         _nkm.min_n = nkm->n.min ?: 1;
 159         _nkm.max_n = nkm->n.max ?: 1 << nkm->n.width;
 160         _nkm.min_k = nkm->k.min ?: 1;
 161         _nkm.max_k = nkm->k.max ?: 1 << nkm->k.width;
 162         _nkm.min_m = 1;
 163         _nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;
 164
 165         ccu_nkm_find_best(parent_rate, rate, &_nkm);
 166
 167         spin_lock_irqsave(nkm->common.lock, flags);
 168
 169         reg = readl(nkm->common.base + nkm->common.reg);
 170         reg &= ~GENMASK(nkm->n.width + nkm->n.shift - 1, nkm->n.shift);
 171         reg &= ~GENMASK(nkm->k.width + nkm->k.shift - 1, nkm->k.shift);
 172         reg &= ~GENMASK(nkm->m.width + nkm->m.shift - 1, nkm->m.shift);
 173
 174         reg |= (_nkm.n - nkm->n.offset) << nkm->n.shift;
 175         reg |= (_nkm.k - nkm->k.offset) << nkm->k.shift;
 176         reg |= (_nkm.m - nkm->m.offset) << nkm->m.shift;
 177         writel(reg, nkm->common.base + nkm->common.reg);
 178
 179         spin_unlock_irqrestore(nkm->common.lock, flags);
 180
 181         ccu_helper_wait_for_lock(&nkm->common, nkm->lock);
 182
 183         return 0;
 184 }
 185
 186 static u8 ccu_nkm_get_parent(struct clk_hw *hw)
 187 {
 188         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 189
 190         return ccu_mux_helper_get_parent(&nkm->common, &nkm->mux);
 191 }
 192
 193 static int ccu_nkm_set_parent(struct clk_hw *hw, u8 index)
 194 {
 195         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 196
 197         return ccu_mux_helper_set_parent(&nkm->common, &nkm->mux, index);
 198 }
 199
 200 const struct clk_ops ccu_nkm_ops = {
 201         .disable        = ccu_nkm_disable,
 202         .enable         = ccu_nkm_enable,
 203         .is_enabled     = ccu_nkm_is_enabled,
 204
 205         .get_parent     = ccu_nkm_get_parent,
 206         .set_parent     = ccu_nkm_set_parent,
 207
 208         .determine_rate = ccu_nkm_determine_rate,
 209         .recalc_rate    = ccu_nkm_recalc_rate,
 210         .set_rate       = ccu_nkm_set_rate,
 211 };