drivers/clk/at91/clk-smd.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 SMD_DIV_SHIFT           8
  21 #define SMD_MAX_DIV             0xf
  22
  23 struct at91sam9x5_clk_smd {
  24         struct clk_hw hw;
  25         struct regmap *regmap;
  26 };
  27
  28 #define to_at91sam9x5_clk_smd(hw) \
  29         container_of(hw, struct at91sam9x5_clk_smd, hw)
  30
  31 static unsigned long at91sam9x5_clk_smd_recalc_rate(struct clk_hw *hw,
  32                                                     unsigned long parent_rate)
  33 {
  34         struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
  35         unsigned int smdr;
  36         u8 smddiv;
  37
  38         regmap_read(smd->regmap, AT91_PMC_SMD, &smdr);
  39         smddiv = (smdr & AT91_PMC_SMD_DIV) >> SMD_DIV_SHIFT;
  40
  41         return parent_rate / (smddiv + 1);
  42 }
  43
  44 static long at91sam9x5_clk_smd_round_rate(struct clk_hw *hw, unsigned long rate,
  45                                           unsigned long *parent_rate)
  46 {
  47         unsigned long div;
  48         unsigned long bestrate;
  49         unsigned long tmp;
  50
  51         if (rate >= *parent_rate)
  52                 return *parent_rate;
  53
  54         div = *parent_rate / rate;
  55         if (div > SMD_MAX_DIV)
  56                 return *parent_rate / (SMD_MAX_DIV + 1);
  57
  58         bestrate = *parent_rate / div;
  59         tmp = *parent_rate / (div + 1);
  60         if (bestrate - rate > rate - tmp)
  61                 bestrate = tmp;
  62
  63         return bestrate;
  64 }
  65
  66 static int at91sam9x5_clk_smd_set_parent(struct clk_hw *hw, u8 index)
  67 {
  68         struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
  69
  70         if (index > 1)
  71                 return -EINVAL;
  72
  73         regmap_update_bits(smd->regmap, AT91_PMC_SMD, AT91_PMC_SMDS,
  74                            index ? AT91_PMC_SMDS : 0);
  75
  76         return 0;
  77 }
  78
  79 static u8 at91sam9x5_clk_smd_get_parent(struct clk_hw *hw)
  80 {
  81         struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
  82         unsigned int smdr;
  83
  84         regmap_read(smd->regmap, AT91_PMC_SMD, &smdr);
  85
  86         return smdr & AT91_PMC_SMDS;
  87 }
  88
  89 static int at91sam9x5_clk_smd_set_rate(struct clk_hw *hw, unsigned long rate,
  90                                        unsigned long parent_rate)
  91 {
  92         struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
  93         unsigned long div = parent_rate / rate;
  94
  95         if (parent_rate % rate || div < 1 || div > (SMD_MAX_DIV + 1))
  96                 return -EINVAL;
  97
  98         regmap_update_bits(smd->regmap, AT91_PMC_SMD, AT91_PMC_SMD_DIV,
  99                            (div - 1) << SMD_DIV_SHIFT);
 100
 101         return 0;
 102 }
 103
 104 static const struct clk_ops at91sam9x5_smd_ops = {
 105         .recalc_rate = at91sam9x5_clk_smd_recalc_rate,
 106         .round_rate = at91sam9x5_clk_smd_round_rate,
 107         .get_parent = at91sam9x5_clk_smd_get_parent,
 108         .set_parent = at91sam9x5_clk_smd_set_parent,
 109         .set_rate = at91sam9x5_clk_smd_set_rate,
 110 };
 111
 112 struct clk_hw * __init
 113 at91sam9x5_clk_register_smd(struct regmap *regmap, const char *name,
 114                             const char **parent_names, u8 num_parents)
 115 {
 116         struct at91sam9x5_clk_smd *smd;
 117         struct clk_hw *hw;
 118         struct clk_init_data init;
 119         int ret;
 120
 121         smd = kzalloc(sizeof(*smd), GFP_KERNEL);
 122         if (!smd)
 123                 return ERR_PTR(-ENOMEM);
 124
 125         init.name = name;
 126         init.ops = &at91sam9x5_smd_ops;
 127         init.parent_names = parent_names;
 128         init.num_parents = num_parents;
 129         init.flags = CLK_SET_RATE_GATE | CLK_SET_PARENT_GATE;
 130
 131         smd->hw.init = &init;
 132         smd->regmap = regmap;
 133
 134         hw = &smd->hw;
 135         ret = clk_hw_register(NULL, &smd->hw);
 136         if (ret) {
 137                 kfree(smd);
 138                 hw = ERR_PTR(ret);
 139         }
 140
 141         return hw;
 142 }