drivers/clk/sunxi-ng/ccu_nkm.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 Maxime Ripard
   4  * Maxime Ripard <maxime.ripard@free-electrons.com>
   5  */
   6
   7 #include <linux/clk-provider.h>
   8 #include <linux/io.h>
   9
  10 #include "ccu_gate.h"
  11 #include "ccu_nkm.h"
  12
  13 struct _ccu_nkm {
  14         unsigned long   n, min_n, max_n;
  15         unsigned long   k, min_k, max_k;
  16         unsigned long   m, min_m, max_m;
  17 };
  18
  19 static void ccu_nkm_find_best(unsigned long parent, unsigned long rate,
  20                               struct _ccu_nkm *nkm)
  21 {
  22         unsigned long best_rate = 0;
  23         unsigned long best_n = 0, best_k = 0, best_m = 0;
  24         unsigned long _n, _k, _m;
  25
  26         for (_k = nkm->min_k; _k <= nkm->max_k; _k++) {
  27                 for (_n = nkm->min_n; _n <= nkm->max_n; _n++) {
  28                         for (_m = nkm->min_m; _m <= nkm->max_m; _m++) {
  29                                 unsigned long tmp_rate;
  30
  31                                 tmp_rate = parent * _n * _k / _m;
  32
  33                                 if (tmp_rate > rate)
  34                                         continue;
  35                                 if ((rate - tmp_rate) < (rate - best_rate)) {
  36                                         best_rate = tmp_rate;
  37                                         best_n = _n;
  38                                         best_k = _k;
  39                                         best_m = _m;
  40                                 }
  41                         }
  42                 }
  43         }
  44
  45         nkm->n = best_n;
  46         nkm->k = best_k;
  47         nkm->m = best_m;
  48 }
  49
  50 static void ccu_nkm_disable(struct clk_hw *hw)
  51 {
  52         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
  53
  54         return ccu_gate_helper_disable(&nkm->common, nkm->enable);
  55 }
  56
  57 static int ccu_nkm_enable(struct clk_hw *hw)
  58 {
  59         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
  60
  61         return ccu_gate_helper_enable(&nkm->common, nkm->enable);
  62 }
  63
  64 static int ccu_nkm_is_enabled(struct clk_hw *hw)
  65 {
  66         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
  67
  68         return ccu_gate_helper_is_enabled(&nkm->common, nkm->enable);
  69 }
  70
  71 static unsigned long ccu_nkm_recalc_rate(struct clk_hw *hw,
  72                                         unsigned long parent_rate)
  73 {
  74         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
  75         unsigned long n, m, k, rate;
  76         u32 reg;
  77
  78         reg = readl(nkm->common.base + nkm->common.reg);
  79
  80         n = reg >> nkm->n.shift;
  81         n &= (1 << nkm->n.width) - 1;
  82         n += nkm->n.offset;
  83         if (!n)
  84                 n++;
  85
  86         k = reg >> nkm->k.shift;
  87         k &= (1 << nkm->k.width) - 1;
  88         k += nkm->k.offset;
  89         if (!k)
  90                 k++;
  91
  92         m = reg >> nkm->m.shift;
  93         m &= (1 << nkm->m.width) - 1;
  94         m += nkm->m.offset;
  95         if (!m)
  96                 m++;
  97
  98         rate = parent_rate * n  * k / m;
  99
 100         if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 101                 rate /= nkm->fixed_post_div;
 102
 103         return rate;
 104 }
 105
 106 static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux,
 107                                         struct clk_hw *hw,
 108                                         unsigned long *parent_rate,
 109                                         unsigned long rate,
 110                                         void *data)
 111 {
 112         struct ccu_nkm *nkm = data;
 113         struct _ccu_nkm _nkm;
 114
 115         _nkm.min_n = nkm->n.min ?: 1;
 116         _nkm.max_n = nkm->n.max ?: 1 << nkm->n.width;
 117         _nkm.min_k = nkm->k.min ?: 1;
 118         _nkm.max_k = nkm->k.max ?: 1 << nkm->k.width;
 119         _nkm.min_m = 1;
 120         _nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;
 121
 122         if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 123                 rate *= nkm->fixed_post_div;
 124
 125         ccu_nkm_find_best(*parent_rate, rate, &_nkm);
 126
 127         rate = *parent_rate * _nkm.n * _nkm.k / _nkm.m;
 128
 129         if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 130                 rate /= nkm->fixed_post_div;
 131
 132         return rate;
 133 }
 134
 135 static int ccu_nkm_determine_rate(struct clk_hw *hw,
 136                                   struct clk_rate_request *req)
 137 {
 138         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 139
 140         return ccu_mux_helper_determine_rate(&nkm->common, &nkm->mux,
 141                                              req, ccu_nkm_round_rate, nkm);
 142 }
 143
 144 static int ccu_nkm_set_rate(struct clk_hw *hw, unsigned long rate,
 145                            unsigned long parent_rate)
 146 {
 147         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 148         struct _ccu_nkm _nkm;
 149         unsigned long flags;
 150         u32 reg;
 151
 152         if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 153                 rate *= nkm->fixed_post_div;
 154
 155         _nkm.min_n = nkm->n.min ?: 1;
 156         _nkm.max_n = nkm->n.max ?: 1 << nkm->n.width;
 157         _nkm.min_k = nkm->k.min ?: 1;
 158         _nkm.max_k = nkm->k.max ?: 1 << nkm->k.width;
 159         _nkm.min_m = 1;
 160         _nkm.max_m = nkm->m.max ?: 1 << nkm->m.width;
 161
 162         ccu_nkm_find_best(parent_rate, rate, &_nkm);
 163
 164         spin_lock_irqsave(nkm->common.lock, flags);
 165
 166         reg = readl(nkm->common.base + nkm->common.reg);
 167         reg &= ~GENMASK(nkm->n.width + nkm->n.shift - 1, nkm->n.shift);
 168         reg &= ~GENMASK(nkm->k.width + nkm->k.shift - 1, nkm->k.shift);
 169         reg &= ~GENMASK(nkm->m.width + nkm->m.shift - 1, nkm->m.shift);
 170
 171         reg |= (_nkm.n - nkm->n.offset) << nkm->n.shift;
 172         reg |= (_nkm.k - nkm->k.offset) << nkm->k.shift;
 173         reg |= (_nkm.m - nkm->m.offset) << nkm->m.shift;
 174         writel(reg, nkm->common.base + nkm->common.reg);
 175
 176         spin_unlock_irqrestore(nkm->common.lock, flags);
 177
 178         ccu_helper_wait_for_lock(&nkm->common, nkm->lock);
 179
 180         return 0;
 181 }
 182
 183 static u8 ccu_nkm_get_parent(struct clk_hw *hw)
 184 {
 185         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 186
 187         return ccu_mux_helper_get_parent(&nkm->common, &nkm->mux);
 188 }
 189
 190 static int ccu_nkm_set_parent(struct clk_hw *hw, u8 index)
 191 {
 192         struct ccu_nkm *nkm = hw_to_ccu_nkm(hw);
 193
 194         return ccu_mux_helper_set_parent(&nkm->common, &nkm->mux, index);
 195 }
 196
 197 const struct clk_ops ccu_nkm_ops = {
 198         .disable        = ccu_nkm_disable,
 199         .enable         = ccu_nkm_enable,
 200         .is_enabled     = ccu_nkm_is_enabled,
 201
 202         .get_parent     = ccu_nkm_get_parent,
 203         .set_parent     = ccu_nkm_set_parent,
 204
 205         .determine_rate = ccu_nkm_determine_rate,
 206         .recalc_rate    = ccu_nkm_recalc_rate,
 207         .set_rate       = ccu_nkm_set_rate,
 208 };