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91b87a47 LW |
1 | /* |
2 | * Driver for the ICST307 VCO clock found in the ARM Reference designs. | |
3 | * We wrap the custom interface from <asm/hardware/icst.h> into the generic | |
4 | * clock framework. | |
5 | * | |
401301cc LW |
6 | * Copyright (C) 2012 Linus Walleij |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
91b87a47 LW |
12 | * TODO: when all ARM reference designs are migrated to generic clocks, the |
13 | * ICST clock code from the ARM tree should probably be merged into this | |
14 | * file. | |
15 | */ | |
16 | #include <linux/clk.h> | |
17 | #include <linux/clkdev.h> | |
18 | #include <linux/err.h> | |
19 | #include <linux/clk-provider.h> | |
7a9ad671 | 20 | #include <linux/io.h> |
91b87a47 LW |
21 | |
22 | #include "clk-icst.h" | |
23 | ||
24 | /** | |
25 | * struct clk_icst - ICST VCO clock wrapper | |
26 | * @hw: corresponding clock hardware entry | |
7a9ad671 LW |
27 | * @vcoreg: VCO register address |
28 | * @lockreg: VCO lock register address | |
91b87a47 LW |
29 | * @params: parameters for this ICST instance |
30 | * @rate: current rate | |
91b87a47 LW |
31 | */ |
32 | struct clk_icst { | |
33 | struct clk_hw hw; | |
7a9ad671 LW |
34 | void __iomem *vcoreg; |
35 | void __iomem *lockreg; | |
91b87a47 LW |
36 | const struct icst_params *params; |
37 | unsigned long rate; | |
91b87a47 LW |
38 | }; |
39 | ||
40 | #define to_icst(_hw) container_of(_hw, struct clk_icst, hw) | |
41 | ||
7a9ad671 LW |
42 | /** |
43 | * vco_get() - get ICST VCO settings from a certain register | |
44 | * @vcoreg: register containing the VCO settings | |
45 | */ | |
46 | static struct icst_vco vco_get(void __iomem *vcoreg) | |
47 | { | |
48 | u32 val; | |
49 | struct icst_vco vco; | |
50 | ||
51 | val = readl(vcoreg); | |
52 | vco.v = val & 0x1ff; | |
53 | vco.r = (val >> 9) & 0x7f; | |
54 | vco.s = (val >> 16) & 03; | |
55 | return vco; | |
56 | } | |
57 | ||
58 | /** | |
59 | * vco_set() - commit changes to an ICST VCO | |
60 | * @locreg: register to poke to unlock the VCO for writing | |
61 | * @vcoreg: register containing the VCO settings | |
62 | * @vco: ICST VCO parameters to commit | |
63 | */ | |
64 | static void vco_set(void __iomem *lockreg, | |
65 | void __iomem *vcoreg, | |
66 | struct icst_vco vco) | |
67 | { | |
68 | u32 val; | |
69 | ||
70 | val = readl(vcoreg) & ~0x7ffff; | |
71 | val |= vco.v | (vco.r << 9) | (vco.s << 16); | |
72 | ||
73 | /* This magic unlocks the VCO so it can be controlled */ | |
74 | writel(0xa05f, lockreg); | |
75 | writel(val, vcoreg); | |
76 | /* This locks the VCO again */ | |
77 | writel(0, lockreg); | |
78 | } | |
79 | ||
80 | ||
91b87a47 LW |
81 | static unsigned long icst_recalc_rate(struct clk_hw *hw, |
82 | unsigned long parent_rate) | |
83 | { | |
84 | struct clk_icst *icst = to_icst(hw); | |
85 | struct icst_vco vco; | |
86 | ||
7a9ad671 | 87 | vco = vco_get(icst->vcoreg); |
91b87a47 LW |
88 | icst->rate = icst_hz(icst->params, vco); |
89 | return icst->rate; | |
90 | } | |
91 | ||
92 | static long icst_round_rate(struct clk_hw *hw, unsigned long rate, | |
93 | unsigned long *prate) | |
94 | { | |
95 | struct clk_icst *icst = to_icst(hw); | |
96 | struct icst_vco vco; | |
97 | ||
98 | vco = icst_hz_to_vco(icst->params, rate); | |
99 | return icst_hz(icst->params, vco); | |
100 | } | |
101 | ||
102 | static int icst_set_rate(struct clk_hw *hw, unsigned long rate, | |
103 | unsigned long parent_rate) | |
104 | { | |
105 | struct clk_icst *icst = to_icst(hw); | |
106 | struct icst_vco vco; | |
107 | ||
108 | vco = icst_hz_to_vco(icst->params, rate); | |
109 | icst->rate = icst_hz(icst->params, vco); | |
7a9ad671 | 110 | vco_set(icst->vcoreg, icst->lockreg, vco); |
91b87a47 LW |
111 | return 0; |
112 | } | |
113 | ||
114 | static const struct clk_ops icst_ops = { | |
115 | .recalc_rate = icst_recalc_rate, | |
116 | .round_rate = icst_round_rate, | |
117 | .set_rate = icst_set_rate, | |
118 | }; | |
119 | ||
7a9ad671 LW |
120 | struct clk *icst_clk_register(struct device *dev, |
121 | const struct clk_icst_desc *desc, | |
122 | void __iomem *base) | |
91b87a47 LW |
123 | { |
124 | struct clk *clk; | |
125 | struct clk_icst *icst; | |
126 | struct clk_init_data init; | |
127 | ||
128 | icst = kzalloc(sizeof(struct clk_icst), GFP_KERNEL); | |
129 | if (!icst) { | |
130 | pr_err("could not allocate ICST clock!\n"); | |
131 | return ERR_PTR(-ENOMEM); | |
132 | } | |
133 | init.name = "icst"; | |
134 | init.ops = &icst_ops; | |
135 | init.flags = CLK_IS_ROOT; | |
136 | init.parent_names = NULL; | |
137 | init.num_parents = 0; | |
138 | icst->hw.init = &init; | |
139 | icst->params = desc->params; | |
7a9ad671 LW |
140 | icst->vcoreg = base + desc->vco_offset; |
141 | icst->lockreg = base + desc->lock_offset; | |
91b87a47 LW |
142 | |
143 | clk = clk_register(dev, &icst->hw); | |
144 | if (IS_ERR(clk)) | |
145 | kfree(icst); | |
146 | ||
147 | return clk; | |
148 | } |