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
uniphier_clk_gate_endisable(struct clk_hw * hw,int enable)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
uniphier_clk_gate_enable(struct clk_hw * hw)40 static int uniphier_clk_gate_enable(struct clk_hw *hw)
41 {
42 return uniphier_clk_gate_endisable(hw, 1);
43 }
44
uniphier_clk_gate_disable(struct clk_hw * hw)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
uniphier_clk_gate_is_enabled(struct clk_hw * hw)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
uniphier_clk_register_gate(struct device * dev,struct regmap * regmap,const char * name,const struct uniphier_clk_gate_data * data)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 }
98