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 struct at91_clk_pms pms;
24 u8 id;
25 };
26
is_pck(int id)27 static inline int is_pck(int id)
28 {
29 return (id >= 8) && (id <= 15);
30 }
31
clk_system_ready(struct regmap * regmap,int id)32 static inline bool clk_system_ready(struct regmap *regmap, int id)
33 {
34 unsigned int status;
35
36 regmap_read(regmap, AT91_PMC_SR, &status);
37
38 return !!(status & (1 << id));
39 }
40
clk_system_prepare(struct clk_hw * hw)41 static int clk_system_prepare(struct clk_hw *hw)
42 {
43 struct clk_system *sys = to_clk_system(hw);
44
45 regmap_write(sys->regmap, AT91_PMC_SCER, 1 << sys->id);
46
47 if (!is_pck(sys->id))
48 return 0;
49
50 while (!clk_system_ready(sys->regmap, sys->id))
51 cpu_relax();
52
53 return 0;
54 }
55
clk_system_unprepare(struct clk_hw * hw)56 static void clk_system_unprepare(struct clk_hw *hw)
57 {
58 struct clk_system *sys = to_clk_system(hw);
59
60 regmap_write(sys->regmap, AT91_PMC_SCDR, 1 << sys->id);
61 }
62
clk_system_is_prepared(struct clk_hw * hw)63 static int clk_system_is_prepared(struct clk_hw *hw)
64 {
65 struct clk_system *sys = to_clk_system(hw);
66 unsigned int status;
67
68 regmap_read(sys->regmap, AT91_PMC_SCSR, &status);
69
70 if (!(status & (1 << sys->id)))
71 return 0;
72
73 if (!is_pck(sys->id))
74 return 1;
75
76 regmap_read(sys->regmap, AT91_PMC_SR, &status);
77
78 return !!(status & (1 << sys->id));
79 }
80
clk_system_save_context(struct clk_hw * hw)81 static int clk_system_save_context(struct clk_hw *hw)
82 {
83 struct clk_system *sys = to_clk_system(hw);
84
85 sys->pms.status = clk_system_is_prepared(hw);
86
87 return 0;
88 }
89
clk_system_restore_context(struct clk_hw * hw)90 static void clk_system_restore_context(struct clk_hw *hw)
91 {
92 struct clk_system *sys = to_clk_system(hw);
93
94 if (sys->pms.status)
95 clk_system_prepare(&sys->hw);
96 }
97
98 static const struct clk_ops system_ops = {
99 .prepare = clk_system_prepare,
100 .unprepare = clk_system_unprepare,
101 .is_prepared = clk_system_is_prepared,
102 .save_context = clk_system_save_context,
103 .restore_context = clk_system_restore_context,
104 };
105
106 struct clk_hw * __init
at91_clk_register_system(struct regmap * regmap,const char * name,const char * parent_name,struct clk_hw * parent_hw,u8 id,unsigned long flags)107 at91_clk_register_system(struct regmap *regmap, const char *name,
108 const char *parent_name, struct clk_hw *parent_hw, u8 id,
109 unsigned long flags)
110 {
111 struct clk_system *sys;
112 struct clk_hw *hw;
113 struct clk_init_data init = {};
114 int ret;
115
116 if (!(parent_name || parent_hw) || id > SYSTEM_MAX_ID)
117 return ERR_PTR(-EINVAL);
118
119 sys = kzalloc(sizeof(*sys), GFP_KERNEL);
120 if (!sys)
121 return ERR_PTR(-ENOMEM);
122
123 init.name = name;
124 init.ops = &system_ops;
125 if (parent_hw)
126 init.parent_hws = (const struct clk_hw **)&parent_hw;
127 else
128 init.parent_names = &parent_name;
129 init.num_parents = 1;
130 init.flags = CLK_SET_RATE_PARENT | flags;
131
132 sys->id = id;
133 sys->hw.init = &init;
134 sys->regmap = regmap;
135
136 hw = &sys->hw;
137 ret = clk_hw_register(NULL, &sys->hw);
138 if (ret) {
139 kfree(sys);
140 hw = ERR_PTR(ret);
141 }
142
143 return hw;
144 }
145