drivers/clk/uniphier/clk-uniphier-gate.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 Socionext Inc.
   4  *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
   5  */
   6
   7 #include <linux/clk-provider.h>
   8 #include <linux/device.h>
   9 #include <linux/regmap.h>
  10
  11 #include "clk-uniphier.h"
  12
  13 struct uniphier_clk_gate {
  14         struct clk_hw hw;
  15         struct regmap *regmap;
  16         unsigned int reg;
  17         unsigned int bit;
  18 };
  19
  20 #define to_uniphier_clk_gate(_hw) \
  21                                 container_of(_hw, struct uniphier_clk_gate, hw)
  22
  23 static int uniphier_clk_gate_endisable(struct clk_hw *hw, int enable)
  24 {
  25         struct uniphier_clk_gate *gate = to_uniphier_clk_gate(hw);
  26
  27         return regmap_write_bits(gate->regmap, gate->reg, BIT(gate->bit),
  28                                  enable ? BIT(gate->bit) : 0);
  29 }
  30
  31 static int uniphier_clk_gate_enable(struct clk_hw *hw)
  32 {
  33         return uniphier_clk_gate_endisable(hw, 1);
  34 }
  35
  36 static void uniphier_clk_gate_disable(struct clk_hw *hw)
  37 {
  38         if (uniphier_clk_gate_endisable(hw, 0) < 0)
  39                 pr_warn("failed to disable clk\n");
  40 }
  41
  42 static int uniphier_clk_gate_is_enabled(struct clk_hw *hw)
  43 {
  44         struct uniphier_clk_gate *gate = to_uniphier_clk_gate(hw);
  45         unsigned int val;
  46
  47         if (regmap_read(gate->regmap, gate->reg, &val) < 0)
  48                 pr_warn("is_enabled() may return wrong result\n");
  49
  50         return !!(val & BIT(gate->bit));
  51 }
  52
  53 static const struct clk_ops uniphier_clk_gate_ops = {
  54         .enable = uniphier_clk_gate_enable,
  55         .disable = uniphier_clk_gate_disable,
  56         .is_enabled = uniphier_clk_gate_is_enabled,
  57 };
  58
  59 struct clk_hw *uniphier_clk_register_gate(struct device *dev,
  60                                           struct regmap *regmap,
  61                                           const char *name,
  62                                 const struct uniphier_clk_gate_data *data)
  63 {
  64         struct uniphier_clk_gate *gate;
  65         struct clk_init_data init;
  66         int ret;
  67
  68         gate = devm_kzalloc(dev, sizeof(*gate), GFP_KERNEL);
  69         if (!gate)
  70                 return ERR_PTR(-ENOMEM);
  71
  72         init.name = name;
  73         init.ops = &uniphier_clk_gate_ops;
  74         init.flags = data->parent_name ? CLK_SET_RATE_PARENT : 0;
  75         init.parent_names = data->parent_name ? &data->parent_name : NULL;
  76         init.num_parents = data->parent_name ? 1 : 0;
  77
  78         gate->regmap = regmap;
  79         gate->reg = data->reg;
  80         gate->bit = data->bit;
  81         gate->hw.init = &init;
  82
  83         ret = devm_clk_hw_register(dev, &gate->hw);
  84         if (ret)
  85                 return ERR_PTR(ret);
  86
  87         return &gate->hw;
  88 }