Commit | Line | Data |
---|---|---|
23b5e15a SG |
1 | /* |
2 | * Copyright 2012 Freescale Semiconductor, Inc. | |
3 | * | |
4 | * The code contained herein is licensed under the GNU General Public | |
5 | * License. You may obtain a copy of the GNU General Public License | |
6 | * Version 2 or later at the following locations: | |
7 | * | |
8 | * http://www.opensource.org/licenses/gpl-license.html | |
9 | * http://www.gnu.org/copyleft/gpl.html | |
10 | */ | |
11 | ||
12 | #include <linux/clk.h> | |
13 | #include <linux/clk-provider.h> | |
14 | #include <linux/err.h> | |
15 | #include <linux/io.h> | |
16 | #include <linux/slab.h> | |
17 | #include "clk.h" | |
18 | ||
19 | /** | |
20 | * struct clk_ref - mxs reference clock | |
21 | * @hw: clk_hw for the reference clock | |
22 | * @reg: register address | |
23 | * @idx: the index of the reference clock within the same register | |
24 | * | |
25 | * The mxs reference clock sources from pll. Every 4 reference clocks share | |
26 | * one register space, and @idx is used to identify them. Each reference | |
27 | * clock has a gate control and a fractional * divider. The rate is calculated | |
28 | * as pll rate * (18 / FRAC), where FRAC = 18 ~ 35. | |
29 | */ | |
30 | struct clk_ref { | |
31 | struct clk_hw hw; | |
32 | void __iomem *reg; | |
33 | u8 idx; | |
34 | }; | |
35 | ||
36 | #define to_clk_ref(_hw) container_of(_hw, struct clk_ref, hw) | |
37 | ||
38 | static int clk_ref_enable(struct clk_hw *hw) | |
39 | { | |
40 | struct clk_ref *ref = to_clk_ref(hw); | |
41 | ||
42 | writel_relaxed(1 << ((ref->idx + 1) * 8 - 1), ref->reg + CLR); | |
43 | ||
44 | return 0; | |
45 | } | |
46 | ||
47 | static void clk_ref_disable(struct clk_hw *hw) | |
48 | { | |
49 | struct clk_ref *ref = to_clk_ref(hw); | |
50 | ||
51 | writel_relaxed(1 << ((ref->idx + 1) * 8 - 1), ref->reg + SET); | |
52 | } | |
53 | ||
54 | static unsigned long clk_ref_recalc_rate(struct clk_hw *hw, | |
55 | unsigned long parent_rate) | |
56 | { | |
57 | struct clk_ref *ref = to_clk_ref(hw); | |
58 | u64 tmp = parent_rate; | |
59 | u8 frac = (readl_relaxed(ref->reg) >> (ref->idx * 8)) & 0x3f; | |
60 | ||
61 | tmp *= 18; | |
62 | do_div(tmp, frac); | |
63 | ||
64 | return tmp; | |
65 | } | |
66 | ||
67 | static long clk_ref_round_rate(struct clk_hw *hw, unsigned long rate, | |
68 | unsigned long *prate) | |
69 | { | |
70 | unsigned long parent_rate = *prate; | |
71 | u64 tmp = parent_rate; | |
72 | u8 frac; | |
73 | ||
74 | tmp = tmp * 18 + rate / 2; | |
75 | do_div(tmp, rate); | |
76 | frac = tmp; | |
77 | ||
78 | if (frac < 18) | |
79 | frac = 18; | |
80 | else if (frac > 35) | |
81 | frac = 35; | |
82 | ||
83 | tmp = parent_rate; | |
84 | tmp *= 18; | |
85 | do_div(tmp, frac); | |
86 | ||
87 | return tmp; | |
88 | } | |
89 | ||
90 | static int clk_ref_set_rate(struct clk_hw *hw, unsigned long rate, | |
91 | unsigned long parent_rate) | |
92 | { | |
93 | struct clk_ref *ref = to_clk_ref(hw); | |
94 | unsigned long flags; | |
95 | u64 tmp = parent_rate; | |
96 | u32 val; | |
97 | u8 frac, shift = ref->idx * 8; | |
98 | ||
99 | tmp = tmp * 18 + rate / 2; | |
100 | do_div(tmp, rate); | |
101 | frac = tmp; | |
102 | ||
103 | if (frac < 18) | |
104 | frac = 18; | |
105 | else if (frac > 35) | |
106 | frac = 35; | |
107 | ||
108 | spin_lock_irqsave(&mxs_lock, flags); | |
109 | ||
110 | val = readl_relaxed(ref->reg); | |
111 | val &= ~(0x3f << shift); | |
112 | val |= frac << shift; | |
113 | writel_relaxed(val, ref->reg); | |
114 | ||
115 | spin_unlock_irqrestore(&mxs_lock, flags); | |
116 | ||
117 | return 0; | |
118 | } | |
119 | ||
120 | static const struct clk_ops clk_ref_ops = { | |
121 | .enable = clk_ref_enable, | |
122 | .disable = clk_ref_disable, | |
123 | .recalc_rate = clk_ref_recalc_rate, | |
124 | .round_rate = clk_ref_round_rate, | |
125 | .set_rate = clk_ref_set_rate, | |
126 | }; | |
127 | ||
128 | struct clk *mxs_clk_ref(const char *name, const char *parent_name, | |
129 | void __iomem *reg, u8 idx) | |
130 | { | |
131 | struct clk_ref *ref; | |
132 | struct clk *clk; | |
133 | struct clk_init_data init; | |
134 | ||
135 | ref = kzalloc(sizeof(*ref), GFP_KERNEL); | |
136 | if (!ref) | |
137 | return ERR_PTR(-ENOMEM); | |
138 | ||
139 | init.name = name; | |
140 | init.ops = &clk_ref_ops; | |
141 | init.flags = 0; | |
142 | init.parent_names = (parent_name ? &parent_name: NULL); | |
143 | init.num_parents = (parent_name ? 1 : 0); | |
144 | ||
145 | ref->reg = reg; | |
146 | ref->idx = idx; | |
147 | ref->hw.init = &init; | |
148 | ||
149 | clk = clk_register(NULL, &ref->hw); | |
150 | if (IS_ERR(clk)) | |
151 | kfree(ref); | |
152 | ||
153 | return clk; | |
154 | } |