drivers/clk/uniphier/clk-uniphier-gate.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/device.h>
  18 #include <linux/regmap.h>
  19
  20 #include "clk-uniphier.h"
  21
  22 struct uniphier_clk_gate {
  23         struct clk_hw hw;
  24         struct regmap *regmap;
  25         unsigned int reg;
  26         unsigned int bit;
  27 };
  28
  29 #define to_uniphier_clk_gate(_hw) \
  30                                 container_of(_hw, struct uniphier_clk_gate, hw)
  31
  32 static int uniphier_clk_gate_endisable(struct clk_hw *hw, int enable)
  33 {
  34         struct uniphier_clk_gate *gate = to_uniphier_clk_gate(hw);
  35
  36         return regmap_write_bits(gate->regmap, gate->reg, BIT(gate->bit),
  37                                  enable ? BIT(gate->bit) : 0);
  38 }
  39
  40 static int uniphier_clk_gate_enable(struct clk_hw *hw)
  41 {
  42         return uniphier_clk_gate_endisable(hw, 1);
  43 }
  44
  45 static void uniphier_clk_gate_disable(struct clk_hw *hw)
  46 {
  47         if (uniphier_clk_gate_endisable(hw, 0) < 0)
  48                 pr_warn("failed to disable clk\n");
  49 }
  50
  51 static int uniphier_clk_gate_is_enabled(struct clk_hw *hw)
  52 {
  53         struct uniphier_clk_gate *gate = to_uniphier_clk_gate(hw);
  54         unsigned int val;
  55
  56         if (regmap_read(gate->regmap, gate->reg, &val) < 0)
  57                 pr_warn("is_enabled() may return wrong result\n");
  58
  59         return !!(val & BIT(gate->bit));
  60 }
  61
  62 static const struct clk_ops uniphier_clk_gate_ops = {
  63         .enable = uniphier_clk_gate_enable,
  64         .disable = uniphier_clk_gate_disable,
  65         .is_enabled = uniphier_clk_gate_is_enabled,
  66 };
  67
  68 struct clk_hw *uniphier_clk_register_gate(struct device *dev,
  69                                           struct regmap *regmap,
  70                                           const char *name,
  71                                 const struct uniphier_clk_gate_data *data)
  72 {
  73         struct uniphier_clk_gate *gate;
  74         struct clk_init_data init;
  75         int ret;
  76
  77         gate = devm_kzalloc(dev, sizeof(*gate), GFP_KERNEL);
  78         if (!gate)
  79                 return ERR_PTR(-ENOMEM);
  80
  81         init.name = name;
  82         init.ops = &uniphier_clk_gate_ops;
  83         init.flags = data->parent_name ? CLK_SET_RATE_PARENT : 0;
  84         init.parent_names = data->parent_name ? &data->parent_name : NULL;
  85         init.num_parents = data->parent_name ? 1 : 0;
  86
  87         gate->regmap = regmap;
  88         gate->reg = data->reg;
  89         gate->bit = data->bit;
  90         gate->hw.init = &init;
  91
  92         ret = devm_clk_hw_register(dev, &gate->hw);
  93         if (ret)
  94                 return ERR_PTR(ret);
  95
  96         return &gate->hw;
  97 }