diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/common/icst525.c |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/arm/common/icst525.c')
-rw-r--r-- | arch/arm/common/icst525.c | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/arch/arm/common/icst525.c b/arch/arm/common/icst525.c new file mode 100644 index 000000000000..943ef88c0379 --- /dev/null +++ b/arch/arm/common/icst525.c | |||
@@ -0,0 +1,160 @@ | |||
1 | /* | ||
2 | * linux/arch/arm/common/icst525.c | ||
3 | * | ||
4 | * Copyright (C) 2003 Deep Blue Solutions, Ltd, All Rights Reserved. | ||
5 | * | ||
6 | * This program is free software; you can redistribute it and/or modify | ||
7 | * it under the terms of the GNU General Public License version 2 as | ||
8 | * published by the Free Software Foundation. | ||
9 | * | ||
10 | * Support functions for calculating clocks/divisors for the ICST525 | ||
11 | * clock generators. See http://www.icst.com/ for more information | ||
12 | * on these devices. | ||
13 | */ | ||
14 | #include <linux/module.h> | ||
15 | #include <linux/kernel.h> | ||
16 | |||
17 | #include <asm/hardware/icst525.h> | ||
18 | |||
19 | /* | ||
20 | * Divisors for each OD setting. | ||
21 | */ | ||
22 | static unsigned char s2div[8] = { 10, 2, 8, 4, 5, 7, 9, 6 }; | ||
23 | |||
24 | unsigned long icst525_khz(const struct icst525_params *p, struct icst525_vco vco) | ||
25 | { | ||
26 | return p->ref * 2 * (vco.v + 8) / ((vco.r + 2) * s2div[vco.s]); | ||
27 | } | ||
28 | |||
29 | EXPORT_SYMBOL(icst525_khz); | ||
30 | |||
31 | /* | ||
32 | * Ascending divisor S values. | ||
33 | */ | ||
34 | static unsigned char idx2s[] = { 1, 3, 4, 7, 5, 2, 6, 0 }; | ||
35 | |||
36 | struct icst525_vco | ||
37 | icst525_khz_to_vco(const struct icst525_params *p, unsigned long freq) | ||
38 | { | ||
39 | struct icst525_vco vco = { .s = 1, .v = p->vd_max, .r = p->rd_max }; | ||
40 | unsigned long f; | ||
41 | unsigned int i = 0, rd, best = (unsigned int)-1; | ||
42 | |||
43 | /* | ||
44 | * First, find the PLL output divisor such | ||
45 | * that the PLL output is within spec. | ||
46 | */ | ||
47 | do { | ||
48 | f = freq * s2div[idx2s[i]]; | ||
49 | |||
50 | /* | ||
51 | * f must be between 10MHz and | ||
52 | * 320MHz (5V) or 200MHz (3V) | ||
53 | */ | ||
54 | if (f > 10000 && f <= p->vco_max) | ||
55 | break; | ||
56 | } while (i < ARRAY_SIZE(idx2s)); | ||
57 | |||
58 | if (i > ARRAY_SIZE(idx2s)) | ||
59 | return vco; | ||
60 | |||
61 | vco.s = idx2s[i]; | ||
62 | |||
63 | /* | ||
64 | * Now find the closest divisor combination | ||
65 | * which gives a PLL output of 'f'. | ||
66 | */ | ||
67 | for (rd = p->rd_min; rd <= p->rd_max; rd++) { | ||
68 | unsigned long fref_div, f_pll; | ||
69 | unsigned int vd; | ||
70 | int f_diff; | ||
71 | |||
72 | fref_div = (2 * p->ref) / rd; | ||
73 | |||
74 | vd = (f + fref_div / 2) / fref_div; | ||
75 | if (vd < p->vd_min || vd > p->vd_max) | ||
76 | continue; | ||
77 | |||
78 | f_pll = fref_div * vd; | ||
79 | f_diff = f_pll - f; | ||
80 | if (f_diff < 0) | ||
81 | f_diff = -f_diff; | ||
82 | |||
83 | if ((unsigned)f_diff < best) { | ||
84 | vco.v = vd - 8; | ||
85 | vco.r = rd - 2; | ||
86 | if (f_diff == 0) | ||
87 | break; | ||
88 | best = f_diff; | ||
89 | } | ||
90 | } | ||
91 | |||
92 | return vco; | ||
93 | } | ||
94 | |||
95 | EXPORT_SYMBOL(icst525_khz_to_vco); | ||
96 | |||
97 | struct icst525_vco | ||
98 | icst525_ps_to_vco(const struct icst525_params *p, unsigned long period) | ||
99 | { | ||
100 | struct icst525_vco vco = { .s = 1, .v = p->vd_max, .r = p->rd_max }; | ||
101 | unsigned long f, ps; | ||
102 | unsigned int i = 0, rd, best = (unsigned int)-1; | ||
103 | |||
104 | ps = 1000000000UL / p->vco_max; | ||
105 | |||
106 | /* | ||
107 | * First, find the PLL output divisor such | ||
108 | * that the PLL output is within spec. | ||
109 | */ | ||
110 | do { | ||
111 | f = period / s2div[idx2s[i]]; | ||
112 | |||
113 | /* | ||
114 | * f must be between 10MHz and | ||
115 | * 320MHz (5V) or 200MHz (3V) | ||
116 | */ | ||
117 | if (f >= ps && f < 100000) | ||
118 | break; | ||
119 | } while (i < ARRAY_SIZE(idx2s)); | ||
120 | |||
121 | if (i > ARRAY_SIZE(idx2s)) | ||
122 | return vco; | ||
123 | |||
124 | vco.s = idx2s[i]; | ||
125 | |||
126 | ps = 500000000UL / p->ref; | ||
127 | |||
128 | /* | ||
129 | * Now find the closest divisor combination | ||
130 | * which gives a PLL output of 'f'. | ||
131 | */ | ||
132 | for (rd = p->rd_min; rd <= p->rd_max; rd++) { | ||
133 | unsigned long f_in_div, f_pll; | ||
134 | unsigned int vd; | ||
135 | int f_diff; | ||
136 | |||
137 | f_in_div = ps * rd; | ||
138 | |||
139 | vd = (f_in_div + f / 2) / f; | ||
140 | if (vd < p->vd_min || vd > p->vd_max) | ||
141 | continue; | ||
142 | |||
143 | f_pll = (f_in_div + vd / 2) / vd; | ||
144 | f_diff = f_pll - f; | ||
145 | if (f_diff < 0) | ||
146 | f_diff = -f_diff; | ||
147 | |||
148 | if ((unsigned)f_diff < best) { | ||
149 | vco.v = vd - 8; | ||
150 | vco.r = rd - 2; | ||
151 | if (f_diff == 0) | ||
152 | break; | ||
153 | best = f_diff; | ||
154 | } | ||
155 | } | ||
156 | |||
157 | return vco; | ||
158 | } | ||
159 | |||
160 | EXPORT_SYMBOL(icst525_ps_to_vco); | ||