1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2013 Boris BREZILLON <b.brezillon@overkiz.com>
4 */
5
6 #include <linux/clk-provider.h>
7 #include <linux/clkdev.h>
8 #include <linux/clk/at91_pmc.h>
9 #include <linux/of.h>
10 #include <linux/mfd/syscon.h>
11 #include <linux/regmap.h>
12
13 #include "pmc.h"
14
15 #define SYSTEM_MAX_ID 31
16
17 #define SYSTEM_MAX_NAME_SZ 32
18
19 #define to_clk_system(hw) container_of(hw, struct clk_system, hw)
20 struct clk_system {
21 struct clk_hw hw;
22 struct regmap *regmap;
23 u8 id;
24 };
25
is_pck(int id)26 static inline int is_pck(int id)
27 {
28 return (id >= 8) && (id <= 15);
29 }
30
clk_system_ready(struct regmap * regmap,int id)31 static inline bool clk_system_ready(struct regmap *regmap, int id)
32 {
33 unsigned int status;
34
35 regmap_read(regmap, AT91_PMC_SR, &status);
36
37 return status & (1 << id) ? 1 : 0;
38 }
39
clk_system_prepare(struct clk_hw * hw)40 static int clk_system_prepare(struct clk_hw *hw)
41 {
42 struct clk_system *sys = to_clk_system(hw);
43
44 regmap_write(sys->regmap, AT91_PMC_SCER, 1 << sys->id);
45
46 if (!is_pck(sys->id))
47 return 0;
48
49 while (!clk_system_ready(sys->regmap, sys->id))
50 cpu_relax();
51
52 return 0;
53 }
54
clk_system_unprepare(struct clk_hw * hw)55 static void clk_system_unprepare(struct clk_hw *hw)
56 {
57 struct clk_system *sys = to_clk_system(hw);
58
59 regmap_write(sys->regmap, AT91_PMC_SCDR, 1 << sys->id);
60 }
61
clk_system_is_prepared(struct clk_hw * hw)62 static int clk_system_is_prepared(struct clk_hw *hw)
63 {
64 struct clk_system *sys = to_clk_system(hw);
65 unsigned int status;
66
67 regmap_read(sys->regmap, AT91_PMC_SCSR, &status);
68
69 if (!(status & (1 << sys->id)))
70 return 0;
71
72 if (!is_pck(sys->id))
73 return 1;
74
75 regmap_read(sys->regmap, AT91_PMC_SR, &status);
76
77 return status & (1 << sys->id) ? 1 : 0;
78 }
79
80 static const struct clk_ops system_ops = {
81 .prepare = clk_system_prepare,
82 .unprepare = clk_system_unprepare,
83 .is_prepared = clk_system_is_prepared,
84 };
85
86 struct clk_hw * __init
at91_clk_register_system(struct regmap * regmap,const char * name,const char * parent_name,u8 id)87 at91_clk_register_system(struct regmap *regmap, const char *name,
88 const char *parent_name, u8 id)
89 {
90 struct clk_system *sys;
91 struct clk_hw *hw;
92 struct clk_init_data init;
93 int ret;
94
95 if (!parent_name || id > SYSTEM_MAX_ID)
96 return ERR_PTR(-EINVAL);
97
98 sys = kzalloc(sizeof(*sys), GFP_KERNEL);
99 if (!sys)
100 return ERR_PTR(-ENOMEM);
101
102 init.name = name;
103 init.ops = &system_ops;
104 init.parent_names = &parent_name;
105 init.num_parents = 1;
106 init.flags = CLK_SET_RATE_PARENT;
107
108 sys->id = id;
109 sys->hw.init = &init;
110 sys->regmap = regmap;
111
112 hw = &sys->hw;
113 ret = clk_hw_register(NULL, &sys->hw);
114 if (ret) {
115 kfree(sys);
116 hw = ERR_PTR(ret);
117 }
118
119 return hw;
120 }
121
