drivers/clk/uniphier/clk-uniphier-cpugear.c

   1 /*
   2  * Copyright (C) 2016 Socionext Inc.
   3  *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/clk-provider.h>
  17 #include <linux/delay.h>
  18 #include <linux/device.h>
  19 #include <linux/regmap.h>
  20
  21 #include "clk-uniphier.h"
  22
  23 #define UNIPHIER_CLK_CPUGEAR_STAT       0       /* status */
  24 #define UNIPHIER_CLK_CPUGEAR_SET        4       /* set */
  25 #define UNIPHIER_CLK_CPUGEAR_UPD        8       /* update */
  26 #define   UNIPHIER_CLK_CPUGEAR_UPD_BIT  BIT(0)
  27
  28 struct uniphier_clk_cpugear {
  29         struct clk_hw hw;
  30         struct regmap *regmap;
  31         unsigned int regbase;
  32         unsigned int mask;
  33 };
  34
  35 #define to_uniphier_clk_cpugear(_hw) \
  36                         container_of(_hw, struct uniphier_clk_cpugear, hw)
  37
  38 static int uniphier_clk_cpugear_set_parent(struct clk_hw *hw, u8 index)
  39 {
  40         struct uniphier_clk_cpugear *gear = to_uniphier_clk_cpugear(hw);
  41         int ret;
  42         unsigned int val;
  43
  44         ret = regmap_write_bits(gear->regmap,
  45                                 gear->regbase + UNIPHIER_CLK_CPUGEAR_SET,
  46                                 gear->mask, index);
  47         if (ret)
  48                 return ret;
  49
  50         ret = regmap_write_bits(gear->regmap,
  51                                 gear->regbase + UNIPHIER_CLK_CPUGEAR_SET,
  52                                 UNIPHIER_CLK_CPUGEAR_UPD_BIT,
  53                                 UNIPHIER_CLK_CPUGEAR_UPD_BIT);
  54         if (ret)
  55                 return ret;
  56
  57         return regmap_read_poll_timeout(gear->regmap,
  58                                 gear->regbase + UNIPHIER_CLK_CPUGEAR_UPD,
  59                                 val, !(val & UNIPHIER_CLK_CPUGEAR_UPD_BIT),
  60                                 0, 1);
  61 }
  62
  63 static u8 uniphier_clk_cpugear_get_parent(struct clk_hw *hw)
  64 {
  65         struct uniphier_clk_cpugear *gear = to_uniphier_clk_cpugear(hw);
  66         int num_parents = clk_hw_get_num_parents(hw);
  67         int ret;
  68         unsigned int val;
  69
  70         ret = regmap_read(gear->regmap,
  71                           gear->regbase + UNIPHIER_CLK_CPUGEAR_STAT, &val);
  72         if (ret)
  73                 return ret;
  74
  75         val &= gear->mask;
  76
  77         return val < num_parents ? val : -EINVAL;
  78 }
  79
  80 static const struct clk_ops uniphier_clk_cpugear_ops = {
  81         .determine_rate = __clk_mux_determine_rate,
  82         .set_parent = uniphier_clk_cpugear_set_parent,
  83         .get_parent = uniphier_clk_cpugear_get_parent,
  84 };
  85
  86 struct clk_hw *uniphier_clk_register_cpugear(struct device *dev,
  87                                          struct regmap *regmap,
  88                                          const char *name,
  89                                 const struct uniphier_clk_cpugear_data *data)
  90 {
  91         struct uniphier_clk_cpugear *gear;
  92         struct clk_init_data init;
  93         int ret;
  94
  95         gear = devm_kzalloc(dev, sizeof(*gear), GFP_KERNEL);
  96         if (!gear)
  97                 return ERR_PTR(-ENOMEM);
  98
  99         init.name = name;
 100         init.ops = &uniphier_clk_cpugear_ops;
 101         init.flags = CLK_SET_RATE_PARENT;
 102         init.parent_names = data->parent_names;
 103         init.num_parents = data->num_parents,
 104
 105         gear->regmap = regmap;
 106         gear->regbase = data->regbase;
 107         gear->mask = data->mask;
 108         gear->hw.init = &init;
 109
 110         ret = devm_clk_hw_register(dev, &gear->hw);
 111         if (ret)
 112                 return ERR_PTR(ret);
 113
 114         return &gear->hw;
 115 }