drivers/clk/at91/clk-plldiv.c

   1 /*
   2  *  Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  */
  10
  11 #include <linux/clk-provider.h>
  12 #include <linux/clkdev.h>
  13 #include <linux/clk/at91_pmc.h>
  14 #include <linux/of.h>
  15 #include <linux/mfd/syscon.h>
  16 #include <linux/regmap.h>
  17
  18 #include "pmc.h"
  19
  20 #define to_clk_plldiv(hw) container_of(hw, struct clk_plldiv, hw)
  21
  22 struct clk_plldiv {
  23         struct clk_hw hw;
  24         struct regmap *regmap;
  25 };
  26
  27 static unsigned long clk_plldiv_recalc_rate(struct clk_hw *hw,
  28                                             unsigned long parent_rate)
  29 {
  30         struct clk_plldiv *plldiv = to_clk_plldiv(hw);
  31         unsigned int mckr;
  32
  33         regmap_read(plldiv->regmap, AT91_PMC_MCKR, &mckr);
  34
  35         if (mckr & AT91_PMC_PLLADIV2)
  36                 return parent_rate / 2;
  37
  38         return parent_rate;
  39 }
  40
  41 static long clk_plldiv_round_rate(struct clk_hw *hw, unsigned long rate,
  42                                         unsigned long *parent_rate)
  43 {
  44         unsigned long div;
  45
  46         if (rate > *parent_rate)
  47                 return *parent_rate;
  48         div = *parent_rate / 2;
  49         if (rate < div)
  50                 return div;
  51
  52         if (rate - div < *parent_rate - rate)
  53                 return div;
  54
  55         return *parent_rate;
  56 }
  57
  58 static int clk_plldiv_set_rate(struct clk_hw *hw, unsigned long rate,
  59                                unsigned long parent_rate)
  60 {
  61         struct clk_plldiv *plldiv = to_clk_plldiv(hw);
  62
  63         if ((parent_rate != rate) && (parent_rate / 2 != rate))
  64                 return -EINVAL;
  65
  66         regmap_update_bits(plldiv->regmap, AT91_PMC_MCKR, AT91_PMC_PLLADIV2,
  67                            parent_rate != rate ? AT91_PMC_PLLADIV2 : 0);
  68
  69         return 0;
  70 }
  71
  72 static const struct clk_ops plldiv_ops = {
  73         .recalc_rate = clk_plldiv_recalc_rate,
  74         .round_rate = clk_plldiv_round_rate,
  75         .set_rate = clk_plldiv_set_rate,
  76 };
  77
  78 struct clk_hw * __init
  79 at91_clk_register_plldiv(struct regmap *regmap, const char *name,
  80                          const char *parent_name)
  81 {
  82         struct clk_plldiv *plldiv;
  83         struct clk_hw *hw;
  84         struct clk_init_data init;
  85         int ret;
  86
  87         plldiv = kzalloc(sizeof(*plldiv), GFP_KERNEL);
  88         if (!plldiv)
  89                 return ERR_PTR(-ENOMEM);
  90
  91         init.name = name;
  92         init.ops = &plldiv_ops;
  93         init.parent_names = parent_name ? &parent_name : NULL;
  94         init.num_parents = parent_name ? 1 : 0;
  95         init.flags = CLK_SET_RATE_GATE;
  96
  97         plldiv->hw.init = &init;
  98         plldiv->regmap = regmap;
  99
 100         hw = &plldiv->hw;
 101         ret = clk_hw_register(NULL, &plldiv->hw);
 102         if (ret) {
 103                 kfree(plldiv);
 104                 hw = ERR_PTR(ret);
 105         }
 106
 107         return hw;
 108 }