1 /*
2 * Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 */
10
11 #include <linux/clk-provider.h>
12 #include <linux/clkdev.h>
13 #include <linux/clk/at91_pmc.h>
14 #include <linux/of.h>
15 #include <linux/mfd/syscon.h>
16 #include <linux/regmap.h>
17
18 #include "pmc.h"
19
20 #define SYSTEM_MAX_ID 31
21
22 #define SYSTEM_MAX_NAME_SZ 32
23
24 #define to_clk_system(hw) container_of(hw, struct clk_system, hw)
25 struct clk_system {
26 struct clk_hw hw;
27 struct regmap *regmap;
28 u8 id;
29 };
30
is_pck(int id)31 static inline int is_pck(int id)
32 {
33 return (id >= 8) && (id <= 15);
34 }
35
clk_system_ready(struct regmap * regmap,int id)36 static inline bool clk_system_ready(struct regmap *regmap, int id)
37 {
38 unsigned int status;
39
40 regmap_read(regmap, AT91_PMC_SR, &status);
41
42 return status & (1 << id) ? 1 : 0;
43 }
44
clk_system_prepare(struct clk_hw * hw)45 static int clk_system_prepare(struct clk_hw *hw)
46 {
47 struct clk_system *sys = to_clk_system(hw);
48
49 regmap_write(sys->regmap, AT91_PMC_SCER, 1 << sys->id);
50
51 if (!is_pck(sys->id))
52 return 0;
53
54 while (!clk_system_ready(sys->regmap, sys->id))
55 cpu_relax();
56
57 return 0;
58 }
59
clk_system_unprepare(struct clk_hw * hw)60 static void clk_system_unprepare(struct clk_hw *hw)
61 {
62 struct clk_system *sys = to_clk_system(hw);
63
64 regmap_write(sys->regmap, AT91_PMC_SCDR, 1 << sys->id);
65 }
66
clk_system_is_prepared(struct clk_hw * hw)67 static int clk_system_is_prepared(struct clk_hw *hw)
68 {
69 struct clk_system *sys = to_clk_system(hw);
70 unsigned int status;
71
72 regmap_read(sys->regmap, AT91_PMC_SCSR, &status);
73
74 if (!(status & (1 << sys->id)))
75 return 0;
76
77 if (!is_pck(sys->id))
78 return 1;
79
80 regmap_read(sys->regmap, AT91_PMC_SR, &status);
81
82 return status & (1 << sys->id) ? 1 : 0;
83 }
84
85 static const struct clk_ops system_ops = {
86 .prepare = clk_system_prepare,
87 .unprepare = clk_system_unprepare,
88 .is_prepared = clk_system_is_prepared,
89 };
90
91 static struct clk_hw * __init
at91_clk_register_system(struct regmap * regmap,const char * name,const char * parent_name,u8 id)92 at91_clk_register_system(struct regmap *regmap, const char *name,
93 const char *parent_name, u8 id)
94 {
95 struct clk_system *sys;
96 struct clk_hw *hw;
97 struct clk_init_data init;
98 int ret;
99
100 if (!parent_name || id > SYSTEM_MAX_ID)
101 return ERR_PTR(-EINVAL);
102
103 sys = kzalloc(sizeof(*sys), GFP_KERNEL);
104 if (!sys)
105 return ERR_PTR(-ENOMEM);
106
107 init.name = name;
108 init.ops = &system_ops;
109 init.parent_names = &parent_name;
110 init.num_parents = 1;
111 init.flags = CLK_SET_RATE_PARENT;
112
113 sys->id = id;
114 sys->hw.init = &init;
115 sys->regmap = regmap;
116
117 hw = &sys->hw;
118 ret = clk_hw_register(NULL, &sys->hw);
119 if (ret) {
120 kfree(sys);
121 hw = ERR_PTR(ret);
122 }
123
124 return hw;
125 }
126
of_at91rm9200_clk_sys_setup(struct device_node * np)127 static void __init of_at91rm9200_clk_sys_setup(struct device_node *np)
128 {
129 int num;
130 u32 id;
131 struct clk_hw *hw;
132 const char *name;
133 struct device_node *sysclknp;
134 const char *parent_name;
135 struct regmap *regmap;
136
137 num = of_get_child_count(np);
138 if (num > (SYSTEM_MAX_ID + 1))
139 return;
140
141 regmap = syscon_node_to_regmap(of_get_parent(np));
142 if (IS_ERR(regmap))
143 return;
144
145 for_each_child_of_node(np, sysclknp) {
146 if (of_property_read_u32(sysclknp, "reg", &id))
147 continue;
148
149 if (of_property_read_string(np, "clock-output-names", &name))
150 name = sysclknp->name;
151
152 parent_name = of_clk_get_parent_name(sysclknp, 0);
153
154 hw = at91_clk_register_system(regmap, name, parent_name, id);
155 if (IS_ERR(hw))
156 continue;
157
158 of_clk_add_hw_provider(sysclknp, of_clk_hw_simple_get, hw);
159 }
160 }
161 CLK_OF_DECLARE(at91rm9200_clk_sys, "atmel,at91rm9200-clk-system",
162 of_at91rm9200_clk_sys_setup);
163