linux/drivers/clk/sunxi-ng/ccu_nkm.c
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   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
  13struct _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
  19static 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
  50static 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
  57static 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
  64static 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
  71static 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
 106static 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
 135static 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
 144static 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
 183static 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
 190static 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
 197const 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};
 209