drivers/clk/at91/clk-smd.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 SMD_DIV_SHIFT           8
  16 #define SMD_MAX_DIV             0xf
  17
  18 struct at91sam9x5_clk_smd {
  19         struct clk_hw hw;
  20         struct regmap *regmap;
  21 };
  22
  23 #define to_at91sam9x5_clk_smd(hw) \
  24         container_of(hw, struct at91sam9x5_clk_smd, hw)
  25
  26 static unsigned long at91sam9x5_clk_smd_recalc_rate(struct clk_hw *hw,
  27                                                     unsigned long parent_rate)
  28 {
  29         struct at91sam9x5_clk_smd *smd = to_at91sam9x5_clk_smd(hw);
  30         unsigned int smdr;
  31         u8 smddiv;
  32
  33         regmap_read(smd->regmap, AT91_PMC_SMD, &smdr);
  34         smddiv = (smdr & AT91_PMC_SMD_DIV) >> SMD_DIV_SHIFT;
  35
  36         return parent_rate / (smddiv + 1);
  37 }
  38
  39 static int at91sam9x5_clk_smd_determine_rate(struct clk_hw *hw,
  40                                              struct clk_rate_request *req)
  41 {
  42         unsigned long div;
  43         unsigned long bestrate;
  44         unsigned long tmp;
  45
  46         if (req->rate >= req->best_parent_rate) {
  47                 req->rate = req->best_parent_rate;
  48                 return 0;
  49         }
  50
  51         div = req->best_parent_rate / req->rate;
  52         if (div > SMD_MAX_DIV) {
  53                 req->rate = req->best_parent_rate / (SMD_MAX_DIV + 1);
  54                 return 0;
  55         }
  56
  57         bestrate = req->best_parent_rate / div;
  58         tmp = req->best_parent_rate / (div + 1);
  59         if (bestrate - req->rate > req->rate - tmp)
  60                 bestrate = tmp;
  61
  62         req->rate = bestrate;
  63         return 0;
  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         .determine_rate = at91sam9x5_clk_smd_determine_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 }