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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/of_address.h> | |
16 | #include <linux/io.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 at91_pmc *pmc; | |
28 | u8 id; | |
29 | }; | |
30 | ||
31 | static int clk_system_enable(struct clk_hw *hw) | |
32 | { | |
33 | struct clk_system *sys = to_clk_system(hw); | |
34 | struct at91_pmc *pmc = sys->pmc; | |
35 | ||
36 | pmc_write(pmc, AT91_PMC_SCER, 1 << sys->id); | |
37 | return 0; | |
38 | } | |
39 | ||
40 | static void clk_system_disable(struct clk_hw *hw) | |
41 | { | |
42 | struct clk_system *sys = to_clk_system(hw); | |
43 | struct at91_pmc *pmc = sys->pmc; | |
44 | ||
45 | pmc_write(pmc, AT91_PMC_SCDR, 1 << sys->id); | |
46 | } | |
47 | ||
48 | static int clk_system_is_enabled(struct clk_hw *hw) | |
49 | { | |
50 | struct clk_system *sys = to_clk_system(hw); | |
51 | struct at91_pmc *pmc = sys->pmc; | |
52 | ||
53 | return !!(pmc_read(pmc, AT91_PMC_SCSR) & (1 << sys->id)); | |
54 | } | |
55 | ||
56 | static const struct clk_ops system_ops = { | |
57 | .enable = clk_system_enable, | |
58 | .disable = clk_system_disable, | |
59 | .is_enabled = clk_system_is_enabled, | |
60 | }; | |
61 | ||
62 | static struct clk * __init | |
63 | at91_clk_register_system(struct at91_pmc *pmc, const char *name, | |
64 | const char *parent_name, u8 id) | |
65 | { | |
66 | struct clk_system *sys; | |
67 | struct clk *clk = NULL; | |
68 | struct clk_init_data init; | |
69 | ||
70 | if (!parent_name || id > SYSTEM_MAX_ID) | |
71 | return ERR_PTR(-EINVAL); | |
72 | ||
73 | sys = kzalloc(sizeof(*sys), GFP_KERNEL); | |
74 | if (!sys) | |
75 | return ERR_PTR(-ENOMEM); | |
76 | ||
77 | init.name = name; | |
78 | init.ops = &system_ops; | |
79 | init.parent_names = &parent_name; | |
80 | init.num_parents = 1; | |
81 | /* | |
82 | * CLK_IGNORE_UNUSED is used to avoid ddrck switch off. | |
83 | * TODO : we should implement a driver supporting at91 ddr controller | |
84 | * (see drivers/memory) which would request and enable the ddrck clock. | |
85 | * When this is done we will be able to remove CLK_IGNORE_UNUSED flag. | |
86 | */ | |
87 | init.flags = CLK_IGNORE_UNUSED; | |
88 | ||
89 | sys->id = id; | |
90 | sys->hw.init = &init; | |
91 | sys->pmc = pmc; | |
92 | ||
93 | clk = clk_register(NULL, &sys->hw); | |
94 | if (IS_ERR(clk)) | |
95 | kfree(sys); | |
96 | ||
97 | return clk; | |
98 | } | |
99 | ||
100 | static void __init | |
101 | of_at91_clk_sys_setup(struct device_node *np, struct at91_pmc *pmc) | |
102 | { | |
103 | int num; | |
104 | u32 id; | |
105 | struct clk *clk; | |
106 | const char *name; | |
107 | struct device_node *sysclknp; | |
108 | const char *parent_name; | |
109 | ||
110 | num = of_get_child_count(np); | |
111 | if (num > (SYSTEM_MAX_ID + 1)) | |
112 | return; | |
113 | ||
114 | for_each_child_of_node(np, sysclknp) { | |
115 | if (of_property_read_u32(sysclknp, "reg", &id)) | |
116 | continue; | |
117 | ||
118 | if (of_property_read_string(np, "clock-output-names", &name)) | |
119 | name = sysclknp->name; | |
120 | ||
121 | parent_name = of_clk_get_parent_name(sysclknp, 0); | |
122 | ||
123 | clk = at91_clk_register_system(pmc, name, parent_name, id); | |
124 | if (IS_ERR(clk)) | |
125 | continue; | |
126 | ||
127 | of_clk_add_provider(sysclknp, of_clk_src_simple_get, clk); | |
128 | } | |
129 | } | |
130 | ||
131 | void __init of_at91rm9200_clk_sys_setup(struct device_node *np, | |
132 | struct at91_pmc *pmc) | |
133 | { | |
134 | of_at91_clk_sys_setup(np, pmc); | |
135 | } |