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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/common/icst525.c
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
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.c160
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diff --git a/arch/arm/common/icst525.c b/arch/arm/common/icst525.c
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+/*
+ * linux/arch/arm/common/icst525.c
+ *
+ * Copyright (C) 2003 Deep Blue Solutions, Ltd, All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Support functions for calculating clocks/divisors for the ICST525
+ * clock generators. See http://www.icst.com/ for more information
+ * on these devices.
+ */
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+#include <asm/hardware/icst525.h>
+
+/*
+ * Divisors for each OD setting.
+ */
+static unsigned char s2div[8] = { 10, 2, 8, 4, 5, 7, 9, 6 };
+
+unsigned long icst525_khz(const struct icst525_params *p, struct icst525_vco vco)
+{
+ return p->ref * 2 * (vco.v + 8) / ((vco.r + 2) * s2div[vco.s]);
+}
+
+EXPORT_SYMBOL(icst525_khz);
+
+/*
+ * Ascending divisor S values.
+ */
+static unsigned char idx2s[] = { 1, 3, 4, 7, 5, 2, 6, 0 };
+
+struct icst525_vco
+icst525_khz_to_vco(const struct icst525_params *p, unsigned long freq)
+{
+ struct icst525_vco vco = { .s = 1, .v = p->vd_max, .r = p->rd_max };
+ unsigned long f;
+ unsigned int i = 0, rd, best = (unsigned int)-1;
+
+ /*
+ * First, find the PLL output divisor such
+ * that the PLL output is within spec.
+ */
+ do {
+ f = freq * s2div[idx2s[i]];
+
+ /*
+ * f must be between 10MHz and
+ * 320MHz (5V) or 200MHz (3V)
+ */
+ if (f > 10000 && f <= p->vco_max)
+ break;
+ } while (i < ARRAY_SIZE(idx2s));
+
+ if (i > ARRAY_SIZE(idx2s))
+ return vco;
+
+ vco.s = idx2s[i];
+
+ /*
+ * Now find the closest divisor combination
+ * which gives a PLL output of 'f'.
+ */
+ for (rd = p->rd_min; rd <= p->rd_max; rd++) {
+ unsigned long fref_div, f_pll;
+ unsigned int vd;
+ int f_diff;
+
+ fref_div = (2 * p->ref) / rd;
+
+ vd = (f + fref_div / 2) / fref_div;
+ if (vd < p->vd_min || vd > p->vd_max)
+ continue;
+
+ f_pll = fref_div * vd;
+ f_diff = f_pll - f;
+ if (f_diff < 0)
+ f_diff = -f_diff;
+
+ if ((unsigned)f_diff < best) {
+ vco.v = vd - 8;
+ vco.r = rd - 2;
+ if (f_diff == 0)
+ break;
+ best = f_diff;
+ }
+ }
+
+ return vco;
+}
+
+EXPORT_SYMBOL(icst525_khz_to_vco);
+
+struct icst525_vco
+icst525_ps_to_vco(const struct icst525_params *p, unsigned long period)
+{
+ struct icst525_vco vco = { .s = 1, .v = p->vd_max, .r = p->rd_max };
+ unsigned long f, ps;
+ unsigned int i = 0, rd, best = (unsigned int)-1;
+
+ ps = 1000000000UL / p->vco_max;
+
+ /*
+ * First, find the PLL output divisor such
+ * that the PLL output is within spec.
+ */
+ do {
+ f = period / s2div[idx2s[i]];
+
+ /*
+ * f must be between 10MHz and
+ * 320MHz (5V) or 200MHz (3V)
+ */
+ if (f >= ps && f < 100000)
+ break;
+ } while (i < ARRAY_SIZE(idx2s));
+
+ if (i > ARRAY_SIZE(idx2s))
+ return vco;
+
+ vco.s = idx2s[i];
+
+ ps = 500000000UL / p->ref;
+
+ /*
+ * Now find the closest divisor combination
+ * which gives a PLL output of 'f'.
+ */
+ for (rd = p->rd_min; rd <= p->rd_max; rd++) {
+ unsigned long f_in_div, f_pll;
+ unsigned int vd;
+ int f_diff;
+
+ f_in_div = ps * rd;
+
+ vd = (f_in_div + f / 2) / f;
+ if (vd < p->vd_min || vd > p->vd_max)
+ continue;
+
+ f_pll = (f_in_div + vd / 2) / vd;
+ f_diff = f_pll - f;
+ if (f_diff < 0)
+ f_diff = -f_diff;
+
+ if ((unsigned)f_diff < best) {
+ vco.v = vd - 8;
+ vco.r = rd - 2;
+ if (f_diff == 0)
+ break;
+ best = f_diff;
+ }
+ }
+
+ return vco;
+}
+
+EXPORT_SYMBOL(icst525_ps_to_vco);