drivers/clk/at91/clk-plldiv.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
   4  */
   5
   6 #include <linux/clk-provider.h>
   7 #include <linux/clkdev.h>
   8 #include <linux/clk/at91_pmc.h>
   9 #include <linux/of.h>
  10 #include <linux/mfd/syscon.h>
  11 #include <linux/regmap.h>
  12
  13 #include "pmc.h"
  14
  15 #define to_clk_plldiv(hw) container_of(hw, struct clk_plldiv, hw)
  16
  17 struct clk_plldiv {
  18         struct clk_hw hw;
  19         struct regmap *regmap;
  20 };
  21
  22 static unsigned long clk_plldiv_recalc_rate(struct clk_hw *hw,
  23                                             unsigned long parent_rate)
  24 {
  25         struct clk_plldiv *plldiv = to_clk_plldiv(hw);
  26         unsigned int mckr;
  27
  28         regmap_read(plldiv->regmap, AT91_PMC_MCKR, &mckr);
  29
  30         if (mckr & AT91_PMC_PLLADIV2)
  31                 return parent_rate / 2;
  32
  33         return parent_rate;
  34 }
  35
  36 static long clk_plldiv_round_rate(struct clk_hw *hw, unsigned long rate,
  37                                         unsigned long *parent_rate)
  38 {
  39         unsigned long div;
  40
  41         if (rate > *parent_rate)
  42                 return *parent_rate;
  43         div = *parent_rate / 2;
  44         if (rate < div)
  45                 return div;
  46
  47         if (rate - div < *parent_rate - rate)
  48                 return div;
  49
  50         return *parent_rate;
  51 }
  52
  53 static int clk_plldiv_set_rate(struct clk_hw *hw, unsigned long rate,
  54                                unsigned long parent_rate)
  55 {
  56         struct clk_plldiv *plldiv = to_clk_plldiv(hw);
  57
  58         if ((parent_rate != rate) && (parent_rate / 2 != rate))
  59                 return -EINVAL;
  60
  61         regmap_update_bits(plldiv->regmap, AT91_PMC_MCKR, AT91_PMC_PLLADIV2,
  62                            parent_rate != rate ? AT91_PMC_PLLADIV2 : 0);
  63
  64         return 0;
  65 }
  66
  67 static const struct clk_ops plldiv_ops = {
  68         .recalc_rate = clk_plldiv_recalc_rate,
  69         .round_rate = clk_plldiv_round_rate,
  70         .set_rate = clk_plldiv_set_rate,
  71 };
  72
  73 struct clk_hw * __init
  74 at91_clk_register_plldiv(struct regmap *regmap, const char *name,
  75                          const char *parent_name)
  76 {
  77         struct clk_plldiv *plldiv;
  78         struct clk_hw *hw;
  79         struct clk_init_data init;
  80         int ret;
  81
  82         plldiv = kzalloc(sizeof(*plldiv), GFP_KERNEL);
  83         if (!plldiv)
  84                 return ERR_PTR(-ENOMEM);
  85
  86         init.name = name;
  87         init.ops = &plldiv_ops;
  88         init.parent_names = parent_name ? &parent_name : NULL;
  89         init.num_parents = parent_name ? 1 : 0;
  90         init.flags = CLK_SET_RATE_GATE;
  91
  92         plldiv->hw.init = &init;
  93         plldiv->regmap = regmap;
  94
  95         hw = &plldiv->hw;
  96         ret = clk_hw_register(NULL, &plldiv->hw);
  97         if (ret) {
  98                 kfree(plldiv);
  99                 hw = ERR_PTR(ret);
 100         }
 101
 102         return hw;
 103 }